Tag: Marine Mammals

Looking through the scope: A world of small marine bugs

By Robyn Norman, GEMM Lab summer 2018 intern, OSU undergraduate

Although the average human may think all zooplankton are the same, to a whale, not all zooplankton are created equal. Just like us, different whales tend to favor different types of food over others. Thus, creating a meal perfect for each individual preference. Using a plankton net off the side of our kayak, each day we take different samples, hoping to figure out more about prey and what species the whales, we see, like best. These samples are then transported back to the lab for analysis and identification. After almost a year of identifying zooplankton and countless hours of looking through the microscope you would think I would have seen everything these tiny organisms have to offer.  Identifying mysid shrimp and other zooplankton to species level can be extremely difficult and time consuming, but equally rewarding. Many zooplankton studies often stop counting at 300 or 400 organisms, however in one very long day in July, I counted over 2,000 individuals. Zooplankton tend to be more difficult to work with due to their small size, fragility, and large quantity.

Figure 1. A sample fresh off the kayak in the beginning stages of identification. Photo by Robyn Norman.

A sample that looks quick and easy can turn into a never-ending search for the smallest of mysids. Most of the mysids that I have sorted can be as small as 5 mm in length. Being difficult to identify is an understatement. Figure 1 shows a sample in the beginning stages of analysis, with a wide range of mysids and other zooplankton. Different species of mysid shrimp generally have the same body shape, structure, size, eyes and everything else you can think of. The only way to easily tell them apart is by their telson, which is a unique structure of their tail. Their telsons cannot be seen with the naked eye and it can also be hard to find with a microscope if you do not know exactly what you are looking for.

 

Throughout my time identifying these tiny creatures I have found 9 different species of mysid from this gray whale foraging ecology project in Port Orford from the 2017 summer. But in 2018 three mysid species have been particularly abundant, Holmesimysis sculpta, Neomysis rayii, and Neomysis mercedis.

Figure 2. Picture taken with microscope of a Holmesimysis sculpta telson. Photo by Robyn Norman.

H. sculpta has a unique telson with about 18 lateral spines that stop as they reach the end of the telson (Figure 2). The end of the telson has 4 large spines that slightly curve to make a fork or scoop-like shape. From my own observations I have also noticed that H. sculpta has darker coloring throughout their bodies and are often heavily pregnant (or at least during the month of August). Neomysis rayii and Neomysis mercedis have been extremely difficult to identify and work with. While N. rayii can grow up to 65 mm, they can also often be the same small size as N. mercedis. The telsons of these two species are very similar, making them too similar to compare and differentiate. However, N. rayii can grow substantially bigger than N. mercedis, making the bigger shrimp easier to identify. Unfortunately, the small N. rayii still give birth to even smaller mysid babies, which can be confused as large N. mercedis. Identifying them in a timely manner is almost impossible. After a long discussion, we decided it would be easier to group these two species of Neomysis together and then sub-group by size. Our three categories were 1-10 mm, 11-15 mm, 16+ mm. According to the literature, N. mercedis are typically 11-15 mm meaning that anything over this size should be a N. rayii (McLaughlin 1980).

Figure 3. Microscopic photo of a gammarid. Photo source: WikiMedia.
Figure 4. Caprellidae found in sample with unique coloration. Photo by Robyn Norman.

While mysids comprise the majority of our samples, they are not the only zooplankton that I see. Amphipods are often caught along with the shrimp. Gammarids look like the terrestrial potato bug and can grow larger than some species of mysid (Fig. 3).

As well as, Caprellidae (Fig. 4) that remind me of little tiny aliens as they have large claws compared to their body size, making it hard to get them out of our plankton net. These impressive creatures are surprisingly hardy and can withstand long times in the freezer or being poked with tweezers under a microscope without dying.

In 2017, there was a high abundance of amphipods found in both of our study sites, Mill Rocks and Tichenor Cove. Mill Rocks surprisingly had 4 times the number of amphipods than Tichenor Cove. This result could be one of the possible reasons gray whales were observed more in Mill Rocks last year. Mill Rocks also has a substantial amount of kelp, a popular place for mysid swarms and amphipods. The occurrence of mysids at each of these sites was almost equal, whereas amphipods were almost exclusively found at Mill Rocks. Mill Rocks also had a higher average number of organisms than Tichenor Cove per samples, potentially creating better feeding grounds for gray whales here in Port Orford.

Analyzing the 2018 data I can already see some differences between the two years. In 2018 the main species of mysid that we are finding in both sites are Neomysis sp. and Holmesimysis sculpta, whereas in 2017 Alienacanthomysis macropsis, a species of mysid identified by their long eye stalks and blunt telson, made up the majority of samples from Tichenor Cove. There has also been a large decrease in amphipods from both locations compared to last year. Two samples from Mill Rocks in 2017 had over 300 amphipods, however this year less than 100 have been counted in total. All these differences in zooplankton prey availability may influence whale behavior and movement patterns. Further data analysis aims to uncover this possibility.

Figure 5. 2017 zooplankton community analysis from Tichenor Cove. There was a higher percentage and abundance of Neomysis rayii (yellow) and Alienacanthomysis macropsis (orange) than in Mill Rocks.
Figure 6. 2017 zooplankton community analysis from Mill Rocks. There was a higher abundance and percentage of amphipods (blue) and Holmesimysis sculpta (brown) than in Tichenor cove. Caprellidae (red) increased during the middle of the season, and decreased substantially towards the end.

The past 6 weeks working as part of the 2018 gray whale foraging ecology research team in Port Orford have been nothing short of amazing. We have seen over 50 whales, identified hundreds of zooplankton, and have spent almost every morning on the water in the kayak. An experience like this is a once in a lifetime opportunity that we were fortunate to be a part of. For the past few years, I have been creating videos to document important and exciting times in my life. I have put together a short video that highlights the amazing things we did every day in Port Orford, as well as the creatures that live just below the surface. I hope you enjoy our Gray Whale Foraging Ecology 2018 video with music by Myd – The Sun. 

[B]reaching New Discoveries about Gray Whales in Oregon

By Haley Kent, Marine Studies Initiative (MSI) & summer GEMM Lab intern, OSU senior

“BLOW!”, yells a team “Whale Storm” member, as mist remains above the water from an exhaling gray whale (Eschrichtius robustus). While based at the Port Orford Field Station for 6 weeks of my final summer as an undergrad at Oregon State University my heart has only grown fonder for marine wildlife. I am still in awe of this amazing opportunity of researching the foraging ecology of gray whales as a Marine Studies Initiative and GEMM Lab intern. From this field work I have already learned so much about gray whales and their zooplankton prey, and now it’s time to analyze the data we have collected and see what ecological stories we can uncover.

Figure 1. Robyn and Haley enjoy their time in the research kayak. Photo by Lisa Hildebrand.

WORK IN THE FIELD

This internship is my first field work experience and I have learned many skills and demands needed to study marine wildlife: waking up before the sun (every day begins with screaming alarms), being engulfed by nature (Port Orford is a jaw-dropping location with rich biodiversity), packing up damp gear and equipment to only get my feet wet in the morning ocean waves again, and of course waiting on the weather to cooperate (fog, wind, swell). I wouldn’t want it any other way.

Figure 2. Smokey sunrise from the research kayak. Photo by Haley Kent.

Whether it is standing above the ocean on the ‘Cliff Site’ or sitting in our two-man kayak, every day of this internship has been full of new learning experiences. Using various field work techniques, such as using a theodolite (surveying equipment to track whale location and behavior), Secchi disks (to measure water clarity), GoPro data collection, taking photos of wildlife, and many more tools, have given me a new bank of valuable skills that will stick with me into my future career.

Figure 3. Haley drops Secchi disk from the research kayak. Photo by Dylan Gregory.

Data Analysis

To maximize my amazing internship experience, I am conducting a small data analysis project using the data we have collected these past weeks and in previous summers.  There are so many questions that can be asked of these data, but I am particularly interested in how many times individual gray whales return to our study area to forage seasonally or annually, and if these individual whales forage preferentially where certain zooplankton prey are available.

Photo Identification

After many hours of data collection in the field either in the kayak or on the cliff, we get to take a breather in the lab to work on various projects we are each assigned. Some job tasks include processing data, identifying zooplankton, and looking through the photos taken that day to potentially identify a known whale. Once photos are processed and saved onto the rugged laptop, they are ready for some serious one on one. Looking through each of the 300 photos captured each day can be very tedious, but it is worthwhile when a match is found. Within the photos of each individual whale I first determine whether it is the left or right side of the whale – if we are lucky we get both! – and maybe even a fluke (tail) photo!

Figure 4. Buttons’ left side. Photo taken by Gray Whale Team of 2018.
Figure 5. Buttons’ left side. Photo taken by Gray Whale Team of 2017.

The angles of these photos (Fig. 4 & 5) are very different, so it could be difficult to tell these are the same whale. But, have a closer look at the pigmentation patterns on this whale. Focus on a single spot or area of spots, and see how patterns line up. Does that match in the same area in the next photo? If yes, you could have yourself a match!

Buttons, one of the identified gray whales (Fig. 4 & 5), was seen in 2016, 17, and 18. I was so excited to identify Buttons for the 3rd year in a row as this result demonstrates this whale’s preference for foraging in Port Orford.

Zooplankton and whale foraging behavior

By using the theodolite we track the whale’s position from the cliff location. I have plugged these coordinates into Google Earth, and compared the coordinates to our zooplankton sample stations from that same day. These methods allow me to assess where the whale spent time, and where it did not, which I can then relate to the zooplankton species and abundance we caught in our sample tows (we use a net from the research kayak to collect samples throughout the water column).

Figure 6. Holmesimysis sculpta. This species can range between 4-12mm. The size of this zooplankton relative to the large gray whales foraging on it shows the whale’s incredible senses for prey preference. Photo source: Scripps Institute of Oceanography.

Results (preliminary)

‘Eyeball’ is one of our resident whales that we have identified regularly throughout this season here in Port Orford. I have compared the amount of time Eyeball has spent near zooplankton stations to the prey community we captured at each station.

There is a positive trend in the amount of time the whale spent in an area with the percent abundance of Holmesimysis sculpta (Fig. 7: blue trend line).

Figure 7. Comparative plot between the amount of time the whale “Eyeball” spent within 50m of each zooplankton sampling station and the relative amount of zooplankton species caught at each station. Note the positive trend between time and Holmesimysis sculpta, and the negative trend relative to Neomysis sp. or Caprellidae.

Conversely, there is an inverse trend with two other zooplankton species:  Neomysis sp. (grey trend line) and Caprellidae (orange trend line). These results suggest that Eyeball has a foraging preference for areas where Holmesimysis sculpta (Fig. 6) is more abundant. Who would have known a whale could be so picky? Once the season comes to an end, I plan to use more of our data to continue to make discoveries about the foraging preferences of gray whales in Oregon.

Where the Wild Things Are

By Dylan Gregory, GEMM Lab summer 2018 intern, OSU undergraduate transfer

In ecology, biodiversity is a term often touted for its key importance in stable ecosystems. Every organism plays its role in the constant struggle of nature, competing and cooperating with each other for survival. The sun provides the initial energy to primary producers, herbivores eat those producers, and predators then eat the consumers. The food chain is a simplistic way to look at how ecosystems work, and of course, it is more like an intricate web of interactions. Fungus and plants work together to trade nutrients and create a vast network of fertile soils; kelp forests provide habitats and food for a variety of prey that marine predators feed on. There are checks and balances between all these organisms that give breath into the beauty and color we see in ecosystems around the world. And, here in Port Orford is no exception. Coming to the project I expected to see some whales, of course. However only three weeks in and I’ve been absolutely astounded with the amount of marine biodiversity we’ve experienced. These past three weeks have been nothing if, well, wild.

Eschrichtius robustus, The Gray Whale

There was no doubt we would see gray whales, that is what we are here for after all, and studying them in the field has been an incredibly enlightening experience. Watching an animal every day for weeks really gets you into their head. You start to connect with them and think about their behaviors in different ways. You begin to realize that the individuals have unique quirks, habits and tendencies. For example, one whale would feed quickly for a time, and then seem to run out of energy and “log” itself, floating on the surface, taking multiple breaths in succession to recover before diving back down. Many whales come from the south, to feed in Mill Rocks before moving to Tichenor Cove, and then leave our study region through “Hell’s Gate” to the North, often resting a moment, taking multiple breaths and then launching into the open sea. Still, when you think you know these whales, they surprise you with an alarming unpredictability, making tracking them a new experience every day.

Figure 1 A gray whale surprised us by surfacing right next to our kayak during a routine zooplankton sampling. The site has shown to have a significant amount of zooplankton and it must have been very interested in the prey available, completely ignoring our presence. Photo by Haley Kent.

The whale in Fig. 1 surprised us, and honestly, being so close to it was as humbling as it was awesome. I expected to see whales, but never expected such a close encounter. These gentle giants are one of our not so distant relatives in the ocean. Many of us do this kind of research for more than just the science and the data. Many of us do it for the connection we feel to our mammal family.

Phoca vitulina richardii, The Pacific Harbor Seal

I absolutely adore these harbor seals! They’re well known for their friendliness towards humans as their dopey little heads pop up out of the water to greet you with a curious look in their eyes. They like to bob in the surf and stare at us while we’re out sampling in the kayak. At first, we got quite excited seeing one, often startling them as we’d squeal “seal!” to each other and they’d dip back under and scurry away. Now though, they seem more comfortable being around our kayak (Fig. 2).

Figure 2 This harbor seal surfaced next to Haley and me shortly before the whale in Fig 1. We named him Courage, as he stuck around and kept us company during the whole encounter. Photo by Haley Kent.

One day a seal followed Lisa and Hayleigh around the jetty on their way back from sampling, swimming around the kayak and investigating them. Out in Mill Rocks, we often see them stretching on top of the rocks, seemingly doing a little yoga session while basking in the morning sun. Despite their cute and cuddly appearance, they are still predators. With plenty of fish to eat and make them happy, these harbor seals are quite plentiful themselves, and I’d like to think we’ve become quite good friends with the little guys.

Tursiops truncatus, The Bottlenose Dolphin

Figure 3 A shot of the dorsal fin seen on August 9th in Mill Rocks. Photo by Dylan Gregory.

One morning we were in Mill Rocks and a large cloud of fog moved in, so we decided to wait it out before making our passage to Tichenor Cove. While sitting there, enjoying a snack, we noticed some dorsal fins popping up about 100 meters from us. Caught by surprise, Haley and I scrambled for our cameras and lo and behold, we noticed they were a small pod of dolphins! Two adults and a calf. Unfortunately, as you can see from our pictures, it is difficult to identify what species they were exactly.

Figure 4 The head and rostrum of the dolphin seen in Mill Rocks on August 9th. Photo by Dylan Gregory.

After communicating with Lisa and Leigh, we have decided that their dorsal fins were far too big and curved to be harbor porpoises (Fig. 3), and the intersection of the head and rostrum seem to have the classic look of a bottlenose dolphin (Fig. 4).

If these were in fact bottlenose dolphins, why are they here in Port Orford, Oregon? It’s uncommon for them to be so far north in our colder waters. Were they foraging for food? Finding refuge from predators? Is it because our waters are becoming warmer? A sighting like this gives more weight to how climate change is affecting our oceans and how marine animals are responding by adapting their migratory and feeding behaviors.

Pisaster and Pycnopodia, The Common Sea Star and the Sunflower Star

Figure 5 Pisaster sea stars and anemones on a rock in Mill Rocks. No Pycnopodia (often called sunflower stars for their many legs) have been spotted in our study zone. Photo by Haley Kent.

One of the coolest aspects of living at the Port Orford Field Station is the fact that we have access to a lot of engagement with other scientists. For instance, we were able to attend a webinar about Sea Star Wasting Disease (SSWD) research currently happening at OSU by Post Doc Sarah Gravem. In a nutshell, a bacterial disease has been infecting sea stars along the west coast, causing a rapid plummet in their populations. Pisaster and Pycnopodia (Fig. 5) have been particularly affected. They are keystone predators, and as such, hold an important role in intertidal ecosystems. Feeding on snails, urchins, other sea stars and various mollusks, these sea stars maintain species populations and allow for a diverse and stable intertidal zone, which then supports many other near shore marine species. While SSWD’s cause is relatively unknown, Pisaster seems to be recovering while Pycnopodia is still struggling. I’ve even heard some anecdotal reports that fishermen here in Port Orford have noticed the lack of Pycnopodia as well, but they are rather pleased that these “ragmops” have stopped mucking up their lines and crab pots.

Below the Surface

There is a charm to the deep, a mystery and wonder that has captured the imagination of humans ad nauseam. Stories, movies, music and masterpieces of art have been inspired by The Abyss. Below the surface lies a diverse world teeming with life, full of questions and answers to be found. While marine mammals are why we’re here, there’s an entirely different environment under the water that is unseen from the safety of our dry, oxygen rich air. Our research doesn’t involve any diving, and so our eyes under the water are a GoPro camera attached to a downrigger on our kayak. Although designed to measure zooplankton community density, we’ve seen quite a bit more than itty bitty sea bugs in the depths of our little harbor here in Port Orford.

Strongylocentrotus purpuratus, The Purple Sea Urchin

Urchins are known for their bright colors and spiny ball like exterior. Close relatives to the sea stars, urchins inhabit the intertidal zones and also take residence within kelp beds. During our kayak training, we passed by some rocks near the cliffs and it was an awesome sight seeing the diversity of intertidal critters such as anemones, sea stars and sea urchins. However, a week into data collection, we have noticed something startling: a large quantity of the urchins cover the seafloor and the kelp, or at least what was left of the kelp (Fig. 6).

Figure 6 Sea Urchins decimating a kelp bed in Tichenor Cove. Photo captured from GoPro footage.

Sea urchins are important members in their communities. They graze on algae and control it from overwhelming the waters, but when left unchecked urchins can completely decimate kelp beds. This pattern is often referred to as “urchin barrens”. Sea otters and sea stars are the urchin’s main predator, and due to the absence of otters and the emergence of SSWD, the occurrence of urchin barrens has risen. An assessment of the reintroduction of the sea otters to Oregon by Dominique Kone, a GEMM Lab graduate student, is underway, and there is a lot of new research on SSWD, both of which could support the ‘ecosystem control’ of urchin populations. We’ve already spotted the urchins wreaking their havoc on the kelp in two separate sites in Tichenor Cove. Since gray whales primarily feed within these kelp beds, this increase in urchin populations is something that we are monitoring. An urchin barren can happen quickly and causes significant ecosystem damage, so this is not something to ignore. If we lose the kelp, it’s easy to imagine that we may lose the whales.

Alopias vulpinus, The Thresher Shark

Figure 7 A thresher shark spotted in Tichenor Cove in Port Orford, OR. Photo captured by GoPro footage.

By far, the most exciting thing I’ve seen so far has been this lovely creature (Fig. 7). The thresher shark usually inhabits the oceanic and coastal zones in tropical and temperate waters. They feed on pelagic schooling fish, squid and sometimes even shorebirds. They attack by whipping their tails (which grow to be the size of their body!) at their prey to stun them. Threshers are on the IUCN Red List of Threatened Species as “Vulnerable” due to their declining populations. They are often hunted for shark fin soup, or by trophy hunters due to their elegant and unique tails.

Haley, our resident shark enthusiast, was able to tell that this shark was a female by the lack of claspers (male appendages) on her pelvic fin. Why was she here though? During the summer, threshers will migrate to colder yet productive northern waters to feed, and on some rare occasions, such as this one, they will come closer to shore. Perhaps she was chasing prey into the harbor and found it to be full of yummy food, or she is a juvenile, which often stay near the continental shelf.

Either way, we were all surprised and excited to see such an exotic and beautiful species of shark caught on camera in our study zone. She even does a little strut in front of the GoPro camera, showing off her beautiful caudal fin!

Protecting our Wilds      

These are only a few examples of the many different animals at work in Port Orford’s ecosystem. Perhaps the biodiversity here is why this is such a hot spot for our whale friends. The productive and lively waters have shown us so many critters, and likely many more we have yet to see. But alas, we have three more weeks of data collection and new discoveries, and I couldn’t be more excited.

“It is a curious situation that the sea, from which life first arose should now be threatened by the activities of one form of that life. But the sea, though changed in a sinister way, will continue to exist; the threat is rather to life itself.”

– Rachel Carson, The Sea Around Us

This experience only drives me further into my pursuit of ecological research. I believe it’s incredibly important to understand the world and how it functions, and to do so before it’s too late. All too often we have breakthrough discoveries in science because something has already fallen apart. Ecosystems are fragile, and climate change, pollution, and other anthropogenic disturbances all have an impact which damage and alter ecosystems and the services they provide. However, it’s an impact we can control with a fundamental understanding of how nature works. With a little hope, some integrity, and a whole lot of passion, I believe we have the power to truly make a difference.

Cold Fingers and Carabiners

By Hayleigh Middleton, GEMM Lab summer 2018 intern, entering OSU undergrad 

Cold Fingers and Carabiners: that’s what most of the past three weeks have been about. We’ve progressively been getting up earlier—with many thanks to the coffee pot and multiple alarms— in order to be on the water collecting data before the wind and fog decide to kick in. Working on the ocean at 7 am with wet hands, metal equipment, a tight suit, and a “refreshing” breeze while trying to keep an eight-foot sit-on-top kayak from tipping over is challenging to say the least. Making sure the Theodolite is perfectly level on its tripod resting on sand-covered ground at the top of a cliff? Not much easier. The air is cold, the wind is cold, the equipment is cold, I’m cold, and now, everything is wet.

Rugged laptop on the cliff site. Photo by Hayleigh Middleton.

I absolutely love it.

Of all the ways I could have chosen to spend my summer before starting college at OSU, I’m so glad I took a chance and asked to spend it here. The official goals of our research project are to monitor and record the foraging habits of the Pacific Coast Feeding Group of gray whales, attempt to find out if specific individuals tend to have site fidelity and forage here year after year, and why or how they choose certain spots to feed over others. What does that mean for me? I get to kayak and take pictures of whales for six weeks! Of course, there’s a bunch of technical stuff and expensive equipment that took us two weeks to learn, but now we’re off to a great start and ready to learn more about these amazing creatures.

We have such a short amount of time to collect all this data to try and fill in the puzzle that is gray whale behavior, and we’re only a few weeks in, but I feel like I’ve already connected with this group of 60,000-pound mammals. That, in essence, is really what we’re doing here. We’re on top of a 33-meter-high cliff watching empty water for hours on the chance that we’ll be able to see a whale, identify it through photo-ID, track it with the theodolite to figure out its behavior, and use our kayak data to figure out its diet and feeding choices. Even though the whales forage up to two kilometers away from our tracking spot, it feels like they know we’re watching them. Sometimes it feels like they’re teasing us—we’ll see one, and once we get the sights fixed on it, it dives down and doesn’t come back up until we’ve turned our attention. One whale got into a very predictable pattern: three blows and then a deep dive, forage for five minutes, pop up half a viewfinder away, three more blows. We set our sights on the third blow and waited for her to resurface.

…and waited.

…and waited.

She swam away and didn’t show herself again.

Other times it’s like they conspire against us. Earlier this week, we spent most of the morning tracking the same whale. A couple hours into the track, another whale popped up right next to the first. Since we use a computerized tracking program, each whale is assigned a group number. That way, we can track each individual’s path and later match it to the photo identification database and sometimes a nickname. The two whales surfaced at just the right frequency and distance apart that deciding which number was currently up was guesswork for a good 15 minutes, but we gave them new track numbers and were able to sort it out later after reviewing our photos.

Searching for whales. Photo by Haley Kent.

On another day, we surveyed for whales until quitting time, which is 3:00 pm. About 2:30 pm, one was finally spotted. I named her Princess because she couldn’t be bothered to bring her body out of the water enough so we could mark her location or take a picture except for when her pectoral fin, the tip of which was “gloved” in white, came out and made a motion like a princess in a parade. When there are whales around, we can’t just say “oh look, 3:00 pm time to go” because this is important data to collect. So, we decided to wait until 3:30 pm to see if she surfaced again within visual range. 3:30 pm came and still no sign of her, so I packed up the theodolite and tripod. As soon as the box was closed, she blew, and another whale surfaced right in front of the cliff. We got some pictures of the closer one for a bit and decided that was enough. As the camera was being lowered into its case, another whale surfaced in the cove. It felt like the first went and told all the whales heading south “hey, these guys want to leave at 3, so show up right around then.” That day we got back to the lab around 5. Even though this meant being on the cliff for almost 10 hours that day, it was thrilling to have seen so many whales in one day.

Then there are times when the whales seem to beg for attention. On our third day on the cliff, we saw what we believe to be a juvenile come swimming into view. We assume that he was a juvenile because he was “small” and quite blank in terms of pigmentation and scarring. He was adorable. He stayed over at Mill Rocks for a while foraging, all of which we “fixed” into the tracking program via the Theodolite, and then he came toward us into the little kelp patch just in front of our cliff site. He would dive down, scoop up some zooplankton to eat, and resurface right in the middle of the kelp. The cutest part is that he would then proceed to roll around in the kelp and further drape himself in it.

Kelp whale. Photo by Lisa Hildebrand.

Having such a young whale come and forage made us wonder if mothers who have site fidelity then teach their young “hey, you don’t have to go all the way north, there’s a ton of good food here in Port Orford.”  Hopefully that’s one of the things we’ll be able to figure out with the data collected with this long–term study. But in the meantime, I still have three weeks of data to collect and a bunch more whales to meet. 

Collaboration – it’s where it’s at.

By Dominique Kone, Masters Student in Marine Resource Management

As I finish my first year of graduate school, I’ve been reflecting on what has helped me develop as a young scientist over the past year. Some of these lessons are somewhat expected: making time for myself outside of academia, reading the literature, and effectively managing my time. Yet, I’ve also learned that working with my peers, other scientists, and experts outside my scientific field can be extremely rewarding.

For my thesis, I will be looking at the potential to reintroduce sea otters to the Oregon coast by identifying suitable habitat and investigating their potential ecological impacts. During this first year, I’ve spent much time getting to know various stakeholder groups, their experiences with this issue, and any advice they may have to inform my work. Through these interactions, I’ve benefitted in ways that would not have been possible if I tried tackling this project on my own.

Source: Seapoint Center for Collaborative Leadership.

When I first started my graduate studies, I was eager to jump head first into my research. However, as someone who had never lived in Oregon before, I didn’t yet have a full grasp of the complexities and context behind my project and was completely unfamiliar with the history of sea otters in Oregon. By engaging with managers, scientists, and advocates, I quickly realized that there was a wealth of knowledge that wasn’t covered in the literature. Information from people who were involved in the initial reintroduction; theories behind the cause of the first failed reintroduction; and most importantly, the various political, social, and culture implications of a potential reintroduction. This information was crucial in developing and honing my research questions, which I would have missed if I had solely relied on the literature.

As my first year in graduate school progressed, I also quickly realized that most people familiar with this issue also had strong opinions and views about how I should conduct my study, whether and how managers should bring sea otters back, and if such an effort will succeed. This input was incredibly helpful in getting to know the issue, and also fostered my development as a scientist as I had to quickly improve my listening and critically-thinking skills to consider my research from different perspectives. One of the benefits of collaboration – particularly with experts outside the marine ecology or sea otter community – is that everyone looks at an issue in a different way. Through my graduate program, I’ve worked with students and faculty in the earth, oceanic, and atmospheric sciences, whom have challenged me to consider other sources of data, other analyses, or different ways of placing my research within various contexts.

Most graduate students when they first start graduate school. Source: Know Your Meme.

One of the major advantages of being a graduate student is that most researchers – including professors, faculty, managers, and fellow graduate students – are more than happy to analyze and discuss my research approach. I’ve obtained advice on statistical analyses, availability and access to data, as well as contacts to other experts. As a graduate student, it’s important for me to consult with more-experienced researchers who can not only explain complex theories or concepts, but who can also validate the appropriateness of my research design and methods. Collaborating with senior researchers is a great way to become established and recognized within the scientific community. Because of this project, I’ve started to become adopted into the marine mammal and sea otter research communities, which is obviously beneficial for my thesis work, but also allows me to start building strong relationships for a career in marine conservation.

Source: Oregon State University.

Looking ahead to my second year of graduate school, I’m eager to make a big push toward completing my thesis, writing manuscripts for journal submission, and communicating my research to various audiences. Throughout this process, it’s still important for me to continue to reach out and collaborate with others within and outside my field as they may help me reach my personal goals. In my opinion, this is exactly what graduate students should be doing. While graduate students may have the ability and some experience to work independently, we are still students, and we are here to learn from and make lasting connections with other researchers and fellow graduate students through these collaborations.

If there’s any advice I would give to an incoming graduate student, it’s this: Collaborate, and collaborate often. Don’t be afraid to work with others because you never know whether you’ll come away with a new perspective, learn something new, come across new research or professional opportunities, or even help others with their research.

Oregon sea otter reintroduction: opinions, perspectives, and theories

By Dominique Kone, Masters Student in Marine Resource Management

Species reintroductions can be hotly contested issues because they can negatively impact other species, ecosystems, and society, as well as failing, altogether. The uncertainty of their outcomes forces stakeholder groups to form their own opinions on whether it’s a good idea to proceed with a reintroduction. When you have several groups with conflicting values and views, managers need to focus on the information most important for them to make a well-informed decision on whether to pursue a reintroduction.

As researchers, we can play an important role by carefully considering and addressing these views through our research, if the appropriate data is available. Despite being in the early days of our study on the potential sea otter reintroduction to Oregon, we have already heard several perspectives regarding its potential success, the type of research we should do, and if sea otters should be brought back to Oregon. Here, I present some of the most interesting and relevant opinions, perspectives, and theories I’ve heard regarding this reintroduction idea.

Source: Suzi Eszterhas

The first reintroduction failed because of X, Y, and Z.

From 1970-1971, managers translocated 93 sea otters to Oregon in a reintroduction effort (Jameson et al. 1982). However, in a matter of 5-6 years, all sea otters disappeared, and the effort was considered a failure. Researchers have theorized that sea otters left Oregon due to a lack of suitable habitat and prey, or to return home to sites from which they were captured. Others have reasoned that managers should have introduced southern sea otters instead of northern sea otters, suggesting one subspecies’ genetic pre-disposition may improve their chance for survival.

Knowing the reasons for this failure may help managers avoid these causes in a future reintroduction attempt and increase its chance of success. We, as scientists, can also gain insight from knowing these causes because this may help us better tailor our research to potentially investigate whether those causes still pose a threat to sea otters during a second attempt. Unfortunately, we lack concrete evidence on what exactly caused this failure, but we can still work to test some these theories.

Source: Mike Baird.

An otter is an otter, no matter where you put it.

There is evidence that northern and southern sea otters are genetically distinct, to a certain degree (Valentine et al. 2008, Larson et al. 2012), and hypotheses have been put forward that the two subspecies may be behaviorally- and ecologically-distinct, too. Studies have shown that northern and southern sea otters have different sized and shaped skulls and teeth, which researchers hypothesize may be a specialized foraging adaptation for consuming different prey species (Campbell & Santana 2017, Timm-Davis et al. 2015). This view suggests that each subspecies has developed unique traits to adapt to the environmental conditions specific to their current ranges. Therefore, when considering which subspecies to bring to Oregon, managers should reintroduce the subspecies with traits better-suited to cope with the types of habitat, prey assemblages, and oceanographic conditions specific to Oregon.

However, other scientists hold the opposite view, and argue that “an otter is an otter” no matter where you put it. This perspective suggests that both subspecies have an equal chance at surviving in any type of suitable habitat because all otters behave in similar ways. Therefore, ecologically, it may not matter which subspecies managers bring to Oregon.

Source: Trover

Oregon doesn’t have enough sea otter habitat.

Kelp is considered important sea otter habitat. In areas with high sea otter densities, such as central and southern California, kelp forests are persistent throughout the year. However, in Oregon, our kelp primarily consists of bull kelp – a slightly more fragile species compared to the durable giant kelp in California. In winter, this bull kelp gets dislodged during intense storms, resulting in seasonal changes in kelp availability. Managers worry that this seasonality could reduce the amount of suitable habitat, to the point where Oregon may not be able to support sea otters.

Yet, we know sea otters used to exist here; therefore, we can assume there must have been some suitable habitat that may persist today. Furthermore, sea otters use a range of habitats, including estuaries, bays, and reefs (Laidre et al. 2009, Lafferty & Tinker 2014, Kvitek et al. 1988). Therefore, even during times when kelp is less abundant, sea otters could use these other forms of habitat along the Oregon coast. Luckily, we have the spatial tools and data to assess how much, where, and when we have suitable habitat, and I will specifically address this in my thesis.

They’ll eat everything!

Sea otters are famous for their voracious appetites for benthic invertebrates, some of which are of commercial and recreational importance to nearshore fisheries. In some cases, sea otters have significantly reduced prey densities, such as sea urchins and Dungeness crab (Garshelis & Garshelis 1984, Estes & Palmisano 1974). However, without a formal analysis, it’s difficult to know if sea otters will have similar impacts on Oregon’s nearshore species, as well as at spatial scale these impacts will occur and whether our fisheries will be affected. We can predict where sea otters are likely to occur based on the presence of suitable habitat, but foraging impacts could be more localized or widespread across sea otter’s entire potential range. To better anticipate these impacts, managers will need an understanding of how much sea otters eat, where foraging could occur based on the availability of prey, and where sea otters and fisheries are likely to interact. I will also address this concern in my thesis.

Source: Suzi Eszterhas

To reintroduce or not to reintroduce? That is the question.

I have found that many scientists and managers have strong opinions on whether it’s appropriate to bring sea otters back to Oregon. Those who argue against a reintroduction often highlight many of the theories already mentioned here – lack of habitat, potential impacts to fisheries, and genetics. While other opponents provided more logistical and practical justifications, such as confounding politics, as well as difficulties in getting public support and regulatory permission to move a federally-listed species.

In contrast, proponents of this idea argue that a reintroduction could augment the recovery of the species by providing additional habitat for the species to rebound to pre-exploitation levels, as well as allowing for increased gene flow between southern and northern sea otter populations. Other proponents have brought up potential benefits to humans, such restoring ecosystem services, providing an economic boost through tourism, or preserving tribal and cultural connections. Such benefits may be worth attempting another reintroduction effort.

As you can see, there are several opinions and perspectives related to a potential sea otter reintroduction to Oregon. While it’s important to consider all opinions, managers still need facts to make key decisions. Scientists can play an important role in providing this information, so managers can make a well-informed decision. Oregon managers have not yet decided whether to proceed with a sea otter reintroduction, but our lab is working to provide them with reliable and accurate science, so they may form their own opinions and arrive at their own decision.

References:

Estes, J. A. and J. F. Palmisano. 1974. Sea otters: the role in structuring nearshore communities. Science. 185: 1058-1060.

Garshelis, D. L. and J. A. Garshelis. 1984. Movements and management of sea otters in Alaska. The Journal of Wildlife Management. 48: 665-678.

Jameson, R. J, Kenyon, K. W., Johnson, A. M., and H. M. Wight. 1982. History and status of translocated sea otter populations in North America. Wildlife Society Bulletin. 10: 100-107.

Lafferty, K. D., and M. T. Tinker. 2014. Sea otters are recolonizing southern California in fits and starts. Ecosphere. 5(5).

Laidre, K. L., Jameson, R. J., Gurarie, E., Jeffries, S. J., and H. Allen. 2009. Spatial habitat use patterns of sea otters in coastal Washington. Journal of Mammalogy. 90(4): 906-917.

Kvitek, R. G. ,Fukayama, A. K., Anderson, B. S., and B. K. Grimm. 1988. Sea otter foraging on deep-burrowing bivalves in a California coastal lagoon. Marine Biology. 98: 157-167.

Larson, S., Jameson, R., Etnier, M., Jones, T., and R. Hall. 2012. Genetic diversity and population parameters of sea otters, Enhydra lutris, before fur trade extirpation from 1741-1911. PLoS ONE. 7(3).

Timm-Davis, L. L, DeWitt, T. J., and C. D. Marshall. 2015. Divergent skull morphology supports two trophic specializations in otters (Lutrinae). PLoS ONE. 10(12).

Valentine et al. 2008. Ancient DNA reveals genotypic relationships among Oregon populations of the sea otter (Enhydra lutris). Conservation Genetics. 9:933-938.

 

 

The Recipe for a “Perfect” Marine Mammal and Seabird Cruise

By Alexa Kownacki, Ph.D. Student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

Science—and fieldwork in particular—is known for its failures. There are websites, blogs, and Twitter pages dedicated to them. This is why, when things go according to plan, I rejoice. When they go even better than expected, I practically tear up from amazement. There is no perfect recipe for a great marine mammal and seabird research cruise, but I would suggest that one would look like this:

 A Great Marine Mammal and Seabird Research Cruise Recipe:

  • A heavy pour of fantastic weather
    • Light on the wind and seas
    • Light on the glare
  • Equal parts amazing crew and good communication
  • A splash of positivity
  • A dash of luck
  • A pinch of delicious food
  • Heaps of marine mammal and seabird sightings
  • Heat to approximately 55-80 degrees F and transit for 10 days along transects at 10-12 knots
The end of another beautiful day at sea on the R/V Shimada. Image source: Alexa K.

The Northern California Current Ecosystem (NCCE) is a highly productive area that is home to a wide variety of cetacean species. Many cetaceans are indicator species of ecosystem health as they consume large quantities of prey from different levels in trophic webs and inhabit diverse areas—from deep-diving beaked whales to gray whales traveling thousands of miles along the eastern north Pacific Ocean. Because cetacean surveys are a predominant survey method in large bodies of water, they can be extremely costly. One alternative to dedicated cetacean surveys is using other research vessels as research platforms and effort becomes transect-based and opportunistic—with less flexibility to deviate from predetermined transects. This decreases expenses, creates collaborative research opportunities, and reduces interference in animal behavior as they are never pursued. Observing animals from large, motorized, research vessels (>100ft) at a steady, significant speed (>10kts/hour), provides a baseline for future, joint research efforts. The NCCE is regularly surveyed by government agencies and institutions on transects that have been repeated nearly every season for decades. This historical data provides critical context for environmental and oceanographic dynamics that impact large ecosystems with commercial and recreational implications.

My research cruise took place aboard the 208.5-foot R/V Bell M. Shimada in the first two weeks of May. The cruise was designated for monitoring the NCCE with the additional position of a marine mammal observer. The established guidelines did not allow for deviation from the predetermined transects. Therefore, mammals were surveyed along preset transects. The ship left port in San Francisco, CA and traveled as far north as Cape Meares, OR. The transects ranged from one nautical mile from shore and two hundred miles offshore. Observations occurred during “on effort” which was defined as when the ship was in transit and moving at a speed above 8 knots per hour dependent upon sea state and visibility. All observations took place on the flybridge during conducive weather conditions and in the bridge (one deck below the flybridge) when excessive precipitation was present. The starboard forward quarter: zero to ninety degrees was surveyed—based on the ship’s direction (with the bow at zero degrees). Both naked eye and 7×50 binoculars were used with at least 30 percent of time binoculars in use. To decrease observer fatigue, which could result in fewer detected sightings, the observer (me) rotated on a 40 minutes “on effort”, 20 minutes “off effort” cycle during long transits (>90 minutes).

Alexa on-effort using binoculars to estimate the distance and bearing of a marine mammal sighted off the starboard bow. Image source: Alexa K.

Data was collected using modifications to the SEEbird Wincruz computer program on a ruggedized laptop and a GPS unit was attached. At the beginning of each day and upon changes in conditions, the ship’s heading, weather conditions, visibility, cloud cover, swell height, swell direction, and Beaufort sea state (BSS) were recorded. Once the BSS or visibility was worse than a “5” (1 is “perfect” and 5 is “very poor”) observations ceased until there was improvement in weather. When a marine mammal was sighted the latitude and longitude were recorded with the exact time stamp. Then, I noted how the animal was sighted—either with binoculars or naked eye—and what action was originally noticed—blow, splash, bird, etc. The bearing and distance were noted using binoculars. The animal was given three generalized behavior categories: traveling, feeding, or milling. A sighting was defined as any marine mammal or group of animals. Therefore, a single sighting would have the species and the best, high, and low estimates for group size.

By my definitions, I had the research cruise of my dreams. There were moments when I imagined people joining this trip as a vacation. I *almost* felt guilty. Then, I remember that after watching water for almost 14 hours (thanks to the amazing weather conditions), I worked on data and reports and class work until midnight. That’s the part that no one talks about: the data. Fieldwork is about collecting data. It’s both what I live for and what makes me nervous. The amount of time, effort, and money that is poured into fieldwork is enormous. The acquisition of the data is not as simple as it seems. When I briefly described my position on this research cruise to friends, they interpret it to be something akin to whale-watching. To some extent, this is true. But largely, it’s grueling hours that leave you fatigued. The differences between fieldwork and what I’ll refer to as “everything else” AKA data analysis, proposal writing, manuscript writing, literature reviewing, lab work, and classwork, are the unbroken smile, the vaguely tanned skin, the hours of laughter, the sea spray, and the magical moments that reassure me that I’ve chosen the correct career path.

Alexa photographing a gray whale at sunset near Newport, OR. Image source: Alexa K.

This cruise was the second leg of the Northern California Current Ecosystem (NCCE) survey, I was the sole Marine Mammal and Seabird Observer—a coveted position. Every morning, I would wake up at 0530hrs, grab some breakfast, and climb to the highest deck: the fly-bridge. Akin to being on the top of the world, the fly-bridge has the best views for the widest span. From 0600hrs to 2000hrs I sat, stood, or danced in a one-meter by one-meter corner of the fly-bridge and surveyed. This visual is why people think I’m whale watching. In reality, I am constantly busy. Nonetheless, I had weather and seas that scientists dream about—and for 10 days! To contrast my luck, you can read Florence’s blog about her cruise. On these same transects, in February, Florence experienced 20-foot seas with heavy rain with very few marine mammal sightings—and of those, the only cetaceans she observed were gray whales close to shore. That starkly contrasts my 10 cetacean species with upwards of 45 sightings and my 20-minute hammock power naps on the fly-bridge under the warm sun.

Pacific white-sided dolphins traveling nearby. Image source: Alexa K.

Marine mammal sightings from this cruise included 10 cetacean species: Pacific white-sided dolphin, Dall’s porpoise, unidentified beaked whale, Cuvier’s beaked whale, gray whale, Minke whale, fin whale, Northern right whale dolphin, blue whale, humpback whale, and transient killer whale and one pinniped species: northern fur seal. What better way to illustrate these sightings than with a map? We are a geospatial lab after all.

Cetacean Sightings on the NCCE Cruise in May 2018. Image source: Alexa K.

This map is the result of data collection. However, it does not capture everything that was observed: sea state, weather, ocean conditions, bathymetry, nutrient levels, etc. There are many variables that can be added to maps–like this one (thanks to my GIS classes I can start adding layers!)–that can provide a better understanding of the ecosystem, predator-prey dynamics, animal behavior, and population health.

The catch from a bottom trawl at a station with some fish and a lot of pyrosomes (pink tube-like creatures). Image source: Alexa K.

Being a Ph.D. student can be physically and mentally demanding. So, when I was offered the opportunity to hone my data collection skills, I leapt for it. I’m happiest in the field: the wind in my face, the sunshine on my back, surrounded by cetaceans, and filled with the knowledge that I’m following my passion—and that this data is contributing to the greater scientific community.

Humpback whale photographed traveling southbound. Image source: Alexa K.

Forecasting blue whale presence: Small steps toward big goals

By Dawn Barlow, MSc student, Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

In 2013, Leigh first published a hypothesis that the South Taranaki Bight region between New Zealand’s North and South Islands is important habitat for blue whales  (Torres 2013). Since then, we have collected three years of data and conducted dedicated analyses, so we now understand that a unique population of blue whales is found in New Zealand, and that they are present in the South Taranaki Bight year-round (Barlow et al. in press).

A blue whale surfaces in the South Taranaki Bight. Photo by Leigh Torres.

This research has garnered quite a bit of political and media attention. A major platform item for the New Zealand Green Party around the last election was the establishment of a marine mammal sanctuary in the South Taranaki Bight. When the world’s largest seismic survey vessel began surveying the South Taranaki Bight this summer for more oil and gas reserves using tremendously loud airguns, there were rallies on the lawn in front of Parliament featuring a large inflatable blue whale that the protesters affectionately refer to as “Janet”. Needless to say, blue whales have made their way into the spotlight in New Zealand.

Janet the inflatable blue whale accompanies protesters on the lawn in front of Parliament in Wellington, New Zealand. Image credit: Greenpeace.

Now that we know there is a unique population of blue whales in New Zealand, what is next? What’s next for me is an exciting combination of both ecology and conservation. If an effective sanctuary is to be implemented, it needs to be more than a simple box drawn on a map to check off a political agenda item—the sanctuary should be informed by our best ecological knowledge of the blue whales and their habitat.

In July, Leigh and I will attend the Society for Conservation Biology meeting in Wellington, New Zealand, and I’ll be giving a presentation titled “Cloudy with a chance of whales: Forecasting blue whale presence based on tiered, bottom-up models”. I’ll be the first to admit, I am not yet forecasting blue whale presence. But I am working my way there, step-by-step, through this tiered, bottom-up approach. In cetacean habitat modeling, we often assume that whale distribution on a foraging ground is determined by their prey’s distribution, and that satellite images of temperature and chlorophyll-a provide an accurate picture of what is going on below the surface. Is this true? With our three years of data including in situ oceanography, krill hydroacoustics, and blue whale distribution and behavior, we are in a unique position to test some of those assumptions, as well as provide managers with an informed management tool to predict blue whale distribution.

What questions will we ask using our data? Firstly, can in situ oceanography (i.e., thermocline depth and temperature, mixed layer depth) predict the distribution and density of blue whale prey (krill)? Then, can those prey patterns be accurately predicted in the absence of oceanographic measurements, using just satellite images? Next, we’ll bring the blue whales back into the picture to ask: can we predict blue whale distribution based on our in situ measurements of oceanography and prey? And finally, in the absence of in situ measurements (which is most often the case), can we forecast where the whales will be based just on remotely-sensed images of the region?

The transducer pole in the water off the RV Star Keys (left) deployed with the echosounder to collect prey availability data, including this image (right) of krill swarms near feeding blue whales. Photo by Leigh Torres.

So, cloudy with a chance of whales? Well, you’ll have to stay tuned for that story in the coming months. In the meantime, I can tell you that as daunting as it is to aggregate so many data streams, each step of the way has a piece of the story to tell. I can’t wait to see how it falls together, both from an ecological modeling perspective and a conservation management objective.

A blue whale surfaces in front of a floating production storage and offloading (FPSO) vessel which services the oil rigs in the South Taranaki Bight. Photo by Dawn Barlow.

 

References:

Torres, L. G. (2013). Evidence for an unrecognised blue whale foraging ground in New Zealand. New Zealand Journal of Marine and Freshwater Research, 47(2), 235-248.

Barlow, D. R., Torres, L. G., Hodge, K. B., Steel, D. Baker, C. S., Chandler, T. E., Bott, N., Constantine, R., Double, M. C., Gill, P., Glasgow, D., Hamner, R. M., Lilley, C., Ogle, M., Olson, P. A., Peters, C., Stockin, K. A., Tessaglia-Hymes, C. T., Klinck, H. (in press). Documentation of a New Zealand blue whale population based on multiple lines of evidence. Endangered Species Research. 

Assessing suitable sea otter habitat along Oregon’s coast

By Dominique Kone, Masters Student in Marine Resource Management

When considering a species reintroduction into an area, it is important to assess the suitability of the area’s habitat before such efforts begin. By doing this assessment at the outset, managers and conservationists can gain a better understanding of the capacity of the area to support a viable population overtime, and ultimately the success of the reintroduction. However, to do a habitat assessment, researchers must first have a base understanding of the species’ ecological characteristics, behavior, and the physical habitat features necessary for the species’ survival. For my thesis, I plan to conduct a similar assessment to identify suitable sea otter habitat to inform a potential sea otter reintroduction to the Oregon coast.

Source: The Tribune.

To start my assessment, I conducted a literature review of studies that observed and recorded the various types of habitats where sea otters currently exist. In my research, I learned that sea otters use in a range of environments, each with a unique set of habitat characteristics. With so many features to sort through, I have focused on specific habitat features that are consistent across most of the current range of sea otters – from Alaska to California – and are important for at least some aspects of sea otters’ everyday life or behavior, specifically foraging. Focusing my analysis on foraging habitat makes sense as sea otters require around 30% of their body weight in food every day (Costa 1978, Reidman & Estes 1990). Meaning sea otters spend most of their day searching for food.

Here, I present four habitat features I will incorporate into my analysis and explain why these features are important for sea otter foraging behavior and survival.

Habitat Features:

  1. Kelp: Sea otters are famously known for the benefits they provide to kelp forests. In the classic three-trophic-level model, sea otters allow for the growth of kelp by keeping sea urchins – consumers of kelp – in check (Estes & Palmisano 1974). Additionally, sea otters and kelp have a mutually-beneficial relationship. Sea otters will often wrap themselves amongst the top of kelp stocks while feeding, resting, or grooming to prevent being carried away by surface currents. Meanwhile, it’s thought that kelp provide a refuge for sea otters seeking to avoid predators, such as sharks, as well as their prey.
Source: The Telegraph.
  1. Distance from Kelp: The use of kelp, by sea otters, is relatively straight-forward. Yet, kelp can still have an influence on sea otter behavior even when not used directly. A 2014 study found that sea otters along the southern California coast were almost 10 times more likely to be located within kelp habitat than outside, while outside kelp beds sea otter numbers declined with distance from the edge of kelp canopies. Sea otters will often forage outside or next to kelp canopies when prey’s available, and even sometimes to socialize in age- or sex-specific rafts (Lafferty & Tinker 2014). These findings indicate that sea otters can and do regularly disperse away from kelp habitat, but because they’re so dependent on kelp, they don’t stray very far.

 

  1. Seafloor Substrate: Sea otters forage over a variety of sediment substrates, including rocks, gravel, seagrass, and even sometimes sand. For example, sea otters hunt sea urchins over rocky substrates, while in other areas they may hunt for crabs in seagrass beds (Estes & Palmisano 1974, Hughes et al. 2014). The type of substrate sea otters forage in typically depends on the substrate needs of their target prey species. Despite some variability across their range, sea otters predominantly forage in rocky substrate environments. Rocky substrate is also necessary for kelp, whose holdfasts need to attach to hard, stable surfaces (Carney et al. 2005).
Source: Save our Seas Foundation.
  1. Depth: Seafloor depth plays a pivotal role in sea otter foraging behavior and therefore acts as a natural boundary that determines how far away from shore sea otters distribute. Many of the prey species sea otters eat – including sea urchins, crabs, and snails – live on the seafloor of the inner continental shelf, requiring sea otters to dive when foraging. Interestingly, sea otters exhibit a non-linear relationship with depth, where most individuals forage at intermediate depths as opposed to extremely shallow or deep waters. One study found the average foraging depth to be around 15 meters (Lafferty & Tinker 2014). This behavior results in a hump-shaped distribution of diving patterns as illustrated in Figure 1 below.
Figure 1. Average probability of occurrence as a function of depth for female (A) and male (B) sea otters as predicted by a synoptic model of space-use (Tinker et al. 2017).

Of course, local conditions and available habitat are always a factor. For example, a study found that sea otters along the coast of Washington foraged further from shore and in slightly shallower environments than sea otters in California (Laidre et al. 2009), indicating that local topography is important in determining distribution. Additionally, diving requires energy and limits how deep sea otters are able to forage for prey. Therefore, diving patterns are not only a function of local topography, but also availability of prey and foraging efficiency in exploiting that prey. Regardless, most sea otter populations follow this hump-shaped diving pattern.

Source: Doretta Smith.

These features are not a complete list of all habitat characteristics that support viable sea otter populations, but seem to be the most consistent throughout their entire range, as well as present in Oregon’s nearshore environment – making them ideal features to include in my analysis. Furthermore, other studies that have predicted suitable sea otter habitat (Tinker et al. 2017), estimated carrying capacity as a product of suitable habitat identification (Laidre et al. 2002), or simply observed sea otter foraging behavior (Estes & Palmisano 1974), have echoed the importance of these four habitat features to sea otter survival.

As with most reintroduction efforts, the process of identifying suitable habitat for the species of interest can be complicated. No two ecosystems or habitats are exactly alike and each comprise their own unique set of physical features and are impacted by environmental processes to varying degrees. The Oregon coast consists of a unique combination of oceanographic conditions and drivers that likely impact the degree and amount of available habitat to sea otters. Despite this, by focusing on the habitat features that are consistently preferred by sea otters across most of their range, I will be able to identify habitat most suitable for sea otter survival in Oregon. The questions of where this habitat is and how much is available are what I’ll determine soon, so stay tuned.

References:

Carney, L. T., Robert Waaland, J., Kilinger, T., and K. Ewing. 2005. Restoration of the bull kelp Nereocystis luetkeana in nearshore rocky habitats. Marine Ecology Progress Series. 302: 49-61.

Costas, D. P. 1978. The ecological energetics, waters, and electrolyte balance of the California sea otter (Enhydra lutris). Ph.D. dissertation, University of California, Santa Cruz.

Estes, J. A. and J. F. Palmisano. 1974. Sea otters: their role in structuring nearshore communities. Science. 185(4156): 1058-1060.

Hughes et al. 2014. Recovery of a top predator mediate negative eutrophic effects on seagrass. Proceedings of the National Academy of Sciences. 110(38): 15313-15318.

Lafferty, K. D. and M. T. Tinker. 2014. Sea otters are recolonizing southern California in fits and starts. Ecosphere. 5(5): 1-11.

Laidre et al. 2002. Estimates of carrying capacity for sea otters in Washington state. Wildlife Society Bulletin. 30(4): 1172-1181.

Laidre et al. 2009. Spatial habitat use patterns of sea otters in coastal Washington. Journal of Mammalogy. 90(4): 906-917.

Tinker et al. 2017. Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2017-1001 (OCS Study BOEM 2017-022), 76 p., http://doi.org/10.3133/ofr20171001.

Reidman, M. L. and J. A. Estes. 1990. The sea otter (Enhydra lutris): behavior, ecology, and natural history. United States Department of the Interior, Fish and Wildlife Service, Biological Report. 90: 1-126.

 

 

Sea Otter Management in the U.S.

By Dominique Kone, Masters Student in Marine Resource Management

Since the first official legal protections in 1911, the U.S. has made great strides in recovering sea otter populations. While much of this progress is due to increased emphasis on understanding sea otter behavior, biology, and ecology, there are also several policies that have been just as instrumental in making sea otter conservation efforts successful. Here, I provide a brief overview of the current legal and regulatory policies used to manage sea otters in the U.S. and explain why having a base understanding of these tools can help our lab as we look into the potential reintroduction of sea otters to the Oregon coast.

Sea otter with pup, Prince William Sound, Alaska. Source: Patrick J. Endres

When we talk about sea otter management in the U.S., the two most obvious laws that come to mind are the Marine Mammal Protection Act (MMPA) and the Endangered Species Act (ESA). In short, the MMPA seeks to prevent the take – including kill, harass, capture, or disturb – or importation of marine mammals and marine mammal products[1]. While the ESA seeks to protect and recover imperiled species – not just marine mammals – and the ecosystems which they depend upon[2]. Both laws are similar in the sense that their primary objectives are to protect and recover at-risk species. However, marine mammals will always be protected under the MMPA, but will only be protected under the ESA if the species is considered threatened or endangered.

On the federal level, the U.S. Fish and Wildlife Service (the Service) is primarily responsible for managing sea otter populations. In the U.S., we manage sea otter populations as five distinct stocks, which differ in their population size and geographic distribution – located in California, Washington, and Alaska state waters (Fig. 1). Because sea otters are divided into these single stocks, management decisions – such as recovery targets or reintroductions – are made on a stock-by-stock basis and are dependent on the stock’s population status. Currently, two of these stocks are federally-listed as threatened under the ESA. Therefore, these two stocks are granted protection under both the ESA and MMPA, while the remaining three stocks are only protected by the MMPA (at the federal level; state management may also apply).

Figure 1. Distribution (approximations of population centers) of sea otter stocks in the U.S. (SW = Southwest Alaskan; SC = Southcentral Alaskan; SE = Southeast Alaskan; WA = Washington, SCA = Southern/Californian)

While the MMPA and ESA are important federal laws, I would be remiss if I didn’t mention the important role that state laws and state agencies have in managing sea otters. According to the MMPA and ESA, if a state develops and maintains a conservation or recovery program with protections consistent with the standards and policies of the MMPA and/or ESA, then the Service may transfer management authority over to the state1,2. However, typically, the Service has opted to manage any stocks listed under the ESA, while states manage all other stocks not listed under the ESA.

Sea otter management in the states of Washington and California is a clear example of this dichotomy. The Washington sea otter stock is not listed under the ESA, and is therefore, managed by the Washington Department of Fish and Wildlife (WDFW), which developed the stock’s recovery plan[3]. In contrast, sea otters along the California coast are listed as threatened under the ESA, and the Service primarily manages the stock’s recovery[4].

Interestingly, sea otter management in Alaska is an exception to this rule. The Southeast and Southcentral sea otter stocks are not listed under the ESA, yet are still managed by the Service. However, the state recognizes sea otters as a species of greatest conservation need in the state’s Wildlife Action Plan, which acts as a recommendation framework for the management and protection of important species and ecosystems[5]. Therefore, even though the state is not the primary management authority for sea otters by law, they still play a role in protecting Alaskan sea otter populations through this action plan.

Table 1. Federal and state listing status of all sea otter stocks within U.S. coastal waters.

States have also implemented their own laws for protecting at-risk species. For instance, while the Washington sea otter stock is not listed under the ESA, it is listed as endangered under Washington state law4. This example raises an important example demonstrating that even if a stock isn’t federally-listed, it may still be protected on the state level, and is always protected under the MMPA. Therefore, if the federal and state listing status do not match, which is the case for most sea otter stocks in the U.S. (Table 1.), the stock still receives management protection at some level.

So why does this matter?

Each of the previously mentioned laws are prohibitive in nature, where the objectives are to prevent and discourage activities which may harm the stock of interest. Yet, agencies may grant exceptions – in the form of permits – for activities, such as scientific research, translocations, commercial/recreational fisheries operations, etc. The permit approval process will oftentimes depend on: (1) the severity or likelihood of that action to harm the species, (2) the species’ federal and state listing status, and (3) the unique approval procedures enforced by the agency. Activities that are perceived to have a high likelihood of harming a species, or involve a species that’s listed under the ESA, will likely require a longer and more arduous approval process.

A sea otter release in Monterey Bay, California. Source: Monterey Bay Aquarium Newsroom.

Understanding these various approval processes is vitally important for our work on the potential reintroduction of sea otters to Oregon because such an effort will no doubt require many permits and a thoughtful permit approval process. Each agency may have their own set of permits, administrative procedures, and approval processes. Therefore, it behooves us to have a clear understanding of these various processes relative to the state, agency, or stock involved. If, hypothetically, a stock is determined as a suitable candidate for reintroduction into Oregon waters, having this understanding will allow us to determine where our research can best inform the effort, what types of information and data are needed to inform the process, and to which agency or stakeholders we must communicate our research.

 

References:

[1] Marine Mammal Protection Act of 1972

[2] Endangered Species Act of 1973

[3] State of Washington. 2004. Sea Otter Recovery Plan. Washington Department of Fish and Wildlife: Wildlife Program

[4] U.S. Fish & Wildlife Service. 2003. Final Revised Recovery Plan for the Southern Sea Otter (Enydra lutris nereis).

[5] Alaska Department of Fish and Game. 2015. Alaska wildlife action plan. Juneau.