By Florence Sullivan, MSc Student Oregon State University, Department of Fisheries and Wildlife
It’s been a couple long, busy weeks here at the GEMM lab as my field season has wrapped up and new labmates are just getting started. There are students in the lab at all hours organizing, processing, and analyzing data. Much of our work investigating the spatial and temporal patterns of marine mammals around the globe takes long hours of parsing through information to bring you results. Systematic sampling is an important research tool but, sometimes, exciting discoveries just wash up at your front door.
Just recently on August 7, 2016, a 39 foot, juvenile female Humpback whale stranded at the Fauntleroy Ferry Terminal in West Seattle, WA. This is very close to my home town, and a recent GEMM lab intern was in the area at the time, so we have a photo of this event for you! The humpback came ashore while still alive, but despite efforts to keep it comfortable and wet, the whale died before the tide returned.
Humpback whale stranded at Fauntleroy Ferry Terminal, West Seattle. photo credit: Sarah Wiesner
A cursory necropsy, conducted on site by researchers from NOAA fisheries and the Cascadia Research Collective, showed the animal had multiple internal parasites and injuries associated with beaching, as well as being in poor nutritional condition overall. There were also bites on the lower jaw consistent with killer whale encounters, and a pod of orca had been spotted in the area the previous day. Necropsies are an important source of data about the basic physiology and biology of marine mammals that is not accessible through any other means. The carcass was towed to a deep-water disposal site approved by federal and state agencies and sunk. Humpback whale sightings in the Salish Sea have increased in the last five years. This, together with the fact that this juvenile was in poor nutritional condition, could indicate that there is competition for resources.
New Species Discovered!
There have been two new species of cetaceans discovered in recent months!
The first exciting announcement was published in the journal Marine Mammal Science in July. Japanese fishermen in the North Pacific have long reported a small, black beaked whale they call karasu, “raven.” In 2013, Japanese researchers published a paper about this black, beaked whale variant of the sub-family Berardiinae using three stranded carcasses, but the sample size was too small to make any conclusions. Three years later there is strong genetic evidence that this is a new species of beaked whale based on (1) genetic analysis of samples from a stranded animal on St. George, Alaska (2) skeletons in a high school in Unalaska, Alaska, (3) skeletons in the Smithsonian archives, and (4) skeletons in other museum and institutional collections around the Pacific Rim. The species still needs to be described and named, but some researchers have suggested Berardius beringiae to honor the sea where it was found. What do you think?
This beaked whale stranded in the Aleutian Islands in 2004, and was measured by Reid Brewer of the University of Alaska Southeast. Analysis of tissue samples later identified the whale as one of the new species. Photo Credit: Don Graves
The second announcement of a new species came from the Smithsonian Institution earlier this month. A skull of the newly-named Arktocara yakataga species was found more than 60 years ago near the present day city of Yakutat, Alaska. Obviously belonging to a prehistoric dolphin, the skull was kept at the Smithsonian’s National Museum of Natural History until new research found that it was actually a previously undiscovered species. A. yakatoga is thought to be a relative of the present day South Asian River Dolphin, and is both the northernmost, and one of the oldest dolphin fossils found to date. This new find is a reminder to everyone that not all discoveries are made in the field. Museum and archival collections continue to play an important role in the advancement of science and knowledge. Check out the link above to see some awesome artistic renderings of the new species, as well as a 3D scan of the skull in question.
Sounds like the next big B-Sci-fi movie doesn’t it? Well, this story is the latest to go viral on the internet. Published on July 20, 216 in the journal Marine Mammal Science, the study investigated accounts of humpback whales interfering with killer whale attacks. Researchers looked at 115 interactions between the two species. Humpbacks initiated 57% of the interactions, and 87% of these moments occurred when the killer whales were attacking or feeding on prey. Surprisingly, only 11% of the prey in these events were humpback whales, while the remaining 89% ranged from other cetaceans to pinnipeds, to a sunfish! The authors suggest that the humpback whales were alerted to attacking killer whales in the area by vocalizations, and that this attracts them to the scene regardless of the species being attacked. Although kin selection (care for or defense of relatives to preserve your family’s genetics even though the action may be detrimental to self), or reciprocity (exchange between individuals for mutual benefit) might explain some of this behavior, the fact that humpback whales so often defended other species means that we cannot rule out the possibility of altruistic behavior. This is a pretty fascinating read, and definitely opens up some new questions for researchers!
By: Cathryn Wood, Lawrence University ’17, summer REU in the GEMM Lab
Greetings from Port Orford! My name is Cathryn, and I am the fourth member of the GEMM Lab’s gray whale foraging ecology research team, which includes Florence, Kelli, and the other Catherine (don’t worry, I go by Cat). Nearly 5 weeks into field season, I am still completely amazed with my first West Coast experience and doing what I’ve always dreamt of: studying marine mammals. Coming from Michigan’s Upper Peninsula, this may seem slightly out of place, but my mom can attest; she read “Baby Beluga” to me every night when I was a toddler. Now a rising senior majoring in biology at Lawrence University, I’ve been focusing my coursework on aquatic and marine ecology to prepare for graduate school where I plan to specialize in marine science. Being part of this research is a very significant step for me into the field.
So how did I end up here, as part of this amazing project and dream, women-in-science team? I am interning through OSU’s Ocean Sciences REU program at the Hatfield Marine Science Center, where the GEMM Lab is located. REU stands for “Research Experience for Undergraduates”, and is an NSF-funded research internship program found in numerous universities around the country. These internships allow undergrads to conduct independent research projects under the guidance of a faculty mentor at the program’s institution. I applied to several REUs this past winter, and was one of 12 undergrads accepted for the program at HMSC. Each of us is paired with different faculty members to work on various projects that cover a diverse range of topics in the marine sciences; everything from estuarine ecology, to bioacoustics. I was ecstatic to learn that I had been paired with Dr. Torres as my faculty mentor to work on Florence’s gray whale project, which had been my first choice during the application process.
My particular research this summer is going to complement Florence’s master’s thesis work by asking new questions regarding the foraging data. While her project focuses on the behavioral states of foraging whales, I will be looking at the whale tracks to see if there are patterns in their foraging behavior found at the individual level. Traditionally, ecological studies have accepted classical niche theory, treating all individuals within a population as ecological equivalents with the same niche width. Any variances present among individuals are often disregarded as having an insignificant consequence on the population dynamics as a whole, but this simplification can overlook the true complexity of that population . The presence of niche variation among conspecifics is known to occur in at least 93 species across a diverse array of taxa, so the concept of individual specialization, and how it can affect ecological processes is gaining recognition progressively in the field (Bolnick et al., 2003). My goal is to determine whether or not the gray whales in this study, and presumably others in the Pacific Coast Feeding Group (PCFG), exhibit individual specialization in their foraging strategies . There are many ways in which individuals can specialize in foraging, but I will be specifically determining if fine scale spatial patterns in the location of foraging bouts exists, regardless of time.
To address my question, I am using the whale tracking data from both 2015 and 2016, and learning to use some very important software in the spatial ecology world along the way through a method that Dr. Torres introduced to me. Starting in ArcGIS, I generate a kernel density layer of a raw track (Fig. 1 ), which describes the relative distribution of where the tracked whale spent time (Fig. 2 ). Next, using the isopleth function in the software Geospatial Modelling Environment, I generate a 50% density contour line that distinguishes where the whale spent at least 50% of its time during the track (Fig. 3 ). Under the assumption that foraging took place in these high density areas, we use these 50% contour lines to describe foraging bout locations. I now go back to ArcGIS to make centroids within each 50% line, which mark the exact foraging bout locations (Fig. 4 ).
Fig. 1 Raw individual whale track.Fig. 2 Kernel Density map of whale track.Fig. 3 50% isopleth contours of locations with highest foraging densitiesFig. 4 Final centroids to signify foraging bouts
These centroids will be determined for every track by an individual whale, and then compared relative to foraging locations of all tracked whales to determine if the individual is foraging in different locations than the population. Then, the tracks of individuals who repeatedly visit the site at least three times will be compared with one another to determine if the repeat whales show spatial and/or temporal patterns in their foraging bout locations, and if specialization at a fine scale is occurring in this population. If you did not quite follow all those methods, no worries, it was a lot for me to take in at first too. I’ve finally gotten the hang of it though, and am grateful to now have these skills going into grad school.
Because I am interested in behavioral ecology and the concept of individuality in animal populations, I am extremely excited to see how this research plays out. Results could be very eye-opening into the fine scale foraging specialization of the PCFG sub-population because they already demonstrate diet specialization on mysid (as opposed to their counterparts in the Bering Sea who feed on benthic organisms) and large scale individual residency patterns along the Pacific Northwest (Newell, 2009; Calambokidis et al., 2012). Most significantly, understanding how individuals vary in their feeding strategies could have very important implications for future conservation measures for the whales, especially during this crucial foraging season where they replenish their energy reserves. Management efforts geared for an “average population” of gray whales could ultimately be ineffective if in fact individuals vary from one another in their foraging strategies. Taking into account the ways in which variation occurs amongst individuals is therefore crucial knowledge for successful conservation approaches.
My project is unique from those of the other REUs because I am simultaneously in the midst of assisting in field season number two of Florence’s project. While most of the other interns are back at Hatfield spending their days in the lab and doing data analyses like a 9-5 job, I am with the team down in Port Orford for field season. This means we’re out doing research every dawn as weather allows. Though I may never have an early bird bone in my body, the sleepy mornings are totally worth it because ecology field work is my favorite part of research. To read more about our methods in the field, check out Florence’s post.
Since Catherine’s last update, we’ve had an eventful week. To our dismay, Downrigger Debacle 2.0 occurred. (To read about the first one, see Kelli’s post). This time it was not the line – our new line has been great. It was a little wire that connected the downrigger line to the pipe that the GoPro and TDR are connected to. It somehow snapped due to what I presume was stress from the currents. Again, it was Catherine and I in the kayak, with a very successful morning on the water coming to a close when it happened. Again, I was in the bow, and she was in the stern deploying the equipment – very déjà vu. When she reeled in an equipment-less line, we at first didn’t know how to break it to Florence and Kelli who were up on the cliff that day. Eventually, Catherine radioed “Brace yourselves…” and we told them the bad news. Once again, they both were very level-headed, methodical, and un-blaming in the moments to follow. We put together the same rescue dive team as last time, and less than a week later, they set off on the mission using the GPS coordinates I had marked while in the kayak. Apparently, between the dredging taking place in the harbor and the phytoplankton bloom, visibility was only about 2 feet during the dive, but they still recovered the equipment, with nothing but baked goods and profuse thanks as payment. We are very grateful for another successful recovery, and are confident that our new attachment mechanism for the downrigger will not require a third rescue mission (Fig. 6-8). Losing the equipment twice now has taught us some very important things about field work. For one, no matter how sound you assume your equipment to be, it is necessary to inspect it for weak points frequently – especially when salt water and currents are in the picture. Perhaps even more importantly, we’ve gotten to practice our problem solving skills and see firsthand how necessary it is to act efficiently and calmly when something goes wrong. In ecological field research you have to be prepared for anything.
Fig. 5 Original setup of GoPro and TDR.Fig. 6 Photo taken after the wire that connected the pole to the downrigger line snapped.Fig. 7 New mechanism for attaching the pole to the downrigger line.Fig. 8 Equipment rescue team: Aaron Galloway and Taylor Eaton diving, Greg Ryder operating the boat, and Florence on board to direct the GPS location of where the equipment was lost.
In other news, unlike our slow-whale days during the first two weeks of the project, we have recently had whales to track nearly every day from the cliff! In fact, the same, small, most likely juvenile, whale pictured in Catherine’s last post has returned several times, and we’ve nicknamed her “Buttons” due to two distinguishing white spots on her tail peduncle near the fluke. Though we tend to refer to Buttons as “her”, we cannot actually tell what the sex is definitively…until now. Remember in Catherine’s post when she described how Buttons defecated a lot, and how our team if, given the opportunity, is supposed to collect the feces when we’re out in the kayak for Leila’s project? Everything from hormone levels to reproductive status to, yes, sex, is held in that poop! Well, Miss (or Mr.) Buttons was in Tichenor Cove today, and to our delight, she performed well in the defecation department once again. Florence and I were on cliff duty tracking her and Kelli and Catherine were in Tichenor on the kayak when we first noticed the defecation. I then radioed down to the kayak team to stop what they were doing and paddle quickly to go collect it before it sank (Fig. 9). Even in these situations, it is important to stay beyond 100 yards of the animal, as required by the MMPA. Florence and I cheered them on and our ladies did indeed get the poop sample, without disturbing the whale (Fig. 10). It was a sight to behold.
Fig. 9 Kelli and Catherine on a mission.Fig. 10 Kelli and Catherine collecting the feces.
We were able to track Buttons for the remainder of our time on the cliff, and were extremely content with the day’s work as we packed all the gear up later in the afternoon. Right before we were about to leave, however, Buttons had one more big treat for us. As we looked to the harbor before starting the trek back to the truck, we paused briefly after noticing a large, white splash in the middle of the harbor, not far from the dock. We paused for a second and thought “No, it can’t be, was that —?” and then we see it again and unanimously yelled “BREACH!” Buttons breached about five times on her way back to Tichenor Cove from where she had been foraging in Mill Rocks. It is rare to see a gray whale breach, so this was really special. Florence managed to capture one of the breaches on video:
At first I thought a big ole humpback had arrived, but nope, it was our Buttons! I am in awe of this little whale, and am forever-grateful to be in the presence of these kinds of moments. She’s definitely made her splash here in Port Orford. I think our team has started to as well.
Bolnick, D. I., Svanback, R., Fordyce, J. A., Yang, L. H., Davis, J. M., Hulsey, C. D., & Forrister, M. L. (2003). Ecology of Individuals: Incidence and Implications of Individual Specialization. The American Naturalist, 161(1), 28.
Calambokidis, J., Laake, J. L., & Klimek, A. (2012). Updated analysis of abundance and population structure of seasonal gray whales in the Pacific Northwest, 1998-2010 (Vol. 2010).
Newell, C. (2009). Ecological Interrelationships Between Summer Resident Gray Whales (Eschrichtius robustus) and Their Prey, Mysid Shrimp (Holmesimysis sculpta and Neomysis rayi) along the Central Oregon Coast.
By: Catherine Lo, Research Intern, Oregon State University ‘16
Hello everyone! My name is Catherine Lo and I am a recent graduate from Oregon State University with a Bachelor’s of Science in Biology with a focus in Marine Biology. It has been an incredible whirlwind leading up to this point: long nights studying for finals, completing my degree, and planning the next steps for my future. I am fortunate to be working as a summer research intern for the GEMM Lab under the supervision of Dr. Leigh Torres and Msc. student Florence Sullivan in their research on the foraging ecology of gray whales. I have dreamed of working with marine mammals, potentially as a research veterinarian and so, capturing this position has been a great opportunity to begin my career.
The days go slow, but the weeks go fast. It’s already week 4 of our field season and the team and I are definitely in the groove of our research. The alarm(s) goes off at 5:00 AM…okay maybe closer to 5:30 AM (oops!), getting dressed for either the kayak or cliff based work, scarfing down breakfast that is usually a diet consisting of toast and peanut butter, and then heading off to the beach to launch the kayak. But this week it was different. A dredging event in Port Orford coordinated by the US Army Corps of Engineers is now taking place right next to the port’s jetty near our study site (Figure 1). This is an important process to move the sediment built up during the year in order for ships to safely navigate in and out of the port. We knew this was going to happen at some point over the summer, and worried that it might impact our research methods and objectives, but at the same time it offers some new opportunities: the chance to see how our GoPro and mysid sampling methods in Tichenor Cove are impacted by the sediment flow from the dredging activities.
Figure 1. View of the dredger from the cliff field site in Port Orford.
My teammate Kelli and I were stationed on the cliff during the first deposit of sediment after the dredge’s first night and morning’s worth of scooping sand. None of us knew where the actual deposit site would be so we kept a good eye on it. The ship headed past the jetty. Turned around and, as a concerned feeling mustered within our field team, it began lowering the platform holding the sand just 250 yards away from our primary study site in Tichenor Cove! At this point, we knew things were going to be different in our samples. Unfortunately along with the sediment stirring up from dredging, we think a phytoplankton bloom is occurring simultaneously. Our GoPro footage lately has been rather clouded making it difficult to identify any mysid relative to our past footage. You can compare Figure 2 to the GoPro image found in Figure 2 of a previous post. It is times like these that we learn how dynamic the ocean is, how human activity can alter the ocean ecosystem, and how to adapt to changes, whether these adaptations are within our reach or not. We are interested to see how our sample sites will change again over time as the dredging operation finishes and the phytoplankton bloom ends.
Figure 2. This GoPro image taken in Tichenor Cove illustrates exactly how murky our view of the water column is with the sediment dredging operation in close proximity.
Aside from the current water clarity situation, we’ve also had some exciting moments! Given how few whales we’ve seen thus far and how the ones we have tracked are predominately hanging by Mill Rocks, which is ~1km east of Tichenor Cove, Dr. Leigh Torres—our head advisor—thought it would be a good idea to check out the mysid scene over there to see what the attraction was. So, we sent our kayak team over there to conduct a few GoPro drops and zooplankton net tows and figure out what is so enticing for the whales.
While conducting this sampling work at Mill Rocks, I and my teammate were lucky enough to encounter a gray whale foraging. And believe me, we were going “off-the-walls” as soon as we heard from the cliff team and saw a blow as the whale surfaced nearby. It was one of those “best time of my life” moments where my dreams of kayaking this close to a whale came true. We fumbled around for our waterproof camera to get clear shots of its lateral flanks for photo identification while also trying to contain our excitement to a more decent level, and at the same time we had to make sure we were not in the whale’s path. There it was; surface after surface, we admired the immense size and beauty of a wild animal before our eyes. The worst part of it was when our camera battery died not long after taking a few pictures, but in a way it gave us a chance to really appreciate the existence of these animals. Note to self during research: always check your batteries are fully charged before heading out!
It baffles me how so often people walk along beaches or drive by without knowing an animal as incredible as this whale is just outside of the shoreline. Every time I’m inside pulling out time stamps or doing photo identification, I always think, “I wonder if there’s a whale in Tichenor Cove or at Mill Rocks right now…Yeah, there probably is one”. Alas, the data management work needs to be done and there’s always the next day for an opportunity of a sighting.
For a few days, our kayak team wasn’t able to work due to a small craft advisory. If you’ve ever been to Port Orford, you’d understand the severity of how windy it gets here. Ranging between 15 knots to 25 knots as early as 7am, so it gets rather difficult to maintain position at each of our sampling stations in our kayak. Fortunately our cliff team was able to set out. We were lucky to see a small whale foraging inside Tichenor Cove and later move onto Mill Rocks. This little one was giving us quite a show! Almost every time it came to the surface, defecation was observed shortly after. As unpleasant as feces might be, it can actually provide an abundance of information about a specific whale including sex, reproductive status, hormone levels, and much more. While doing our research, we are always keeping an eye out for signs of defecation in order to collect samples for another lab member’s PhD work. Here you can check out more information about Leila’s research. Figure 3 depicts a great image of defecation captured by our cliff team.
Figure 3. Gray whale defecating as it dives into the water in Tichenor Cove.Figure 4. Gray whale swimming in Tichenor Cove taken by fellow intern Cathryn Wood.
In addition to helping out Leila’s work, we recently began a collaboration with Aaron Galloway from The Oregon Institute of Marine Biology (OIMB). Aaron and his post-doc are looking at the fatty acid composition of mysid as an approach to eventually infer the diet of an aquatic animal. Check out his website which is linked to his name to learn more about the basis of his approach! While we collect mysid samples for them, in return they give us substantial information about the energy content of the mysid. This information on the energetic content of mysid will help the GEMM Lab answer questions about how much mysid gray whales need to eat.
Oregon State University and University of Oregon have a long-standing, intense rivalry. However, as an Alumna from Oregon State, I am amazed and thrilled to see how these two institutions can come together and collaborate. I mean, we’re all here for the same thing. Science, right? It creates the opportunity to apply integrative research by taking advantage of various expertise and resources. If we have those chances to reach out to others, why not make the most of it? In the end, sound science is what really matters, not rooting for the ducks or beavers.
My marine science background is based on my experiences looking at tidepools and hopping around on rocks to understand how vast intertidal communities range from invertebrates to algae. These experiences were an incredible part of my life, but now I look at the ocean unsure of what animals or environmental situations I might encounter. That’s what makes it so attractive. Don’t get me wrong. The intertidal will always hold a special place in my heart, but the endless possibilities of being a part of this marine mammal research team is priceless. I have learned so much about myself including my strengths and weaknesses. Living in Port Orford, which is a small coastal town with just a little over 1,000 people gives you a new perspective. The community has been very welcoming and I have appreciated how so much interest is placed on the kind of work we do. As I eat my nightly bowl of ice cream, I think about how, from here on out, the good and the bad can only bring a lifetime of skills and memories.
Figure 5. Me being extremely happy to be out on the kayak on a beautiful morning.
Hello Everyone, and welcome back for season two of our ever-expanding research project(s) about the gray whales of the Oregon coast!
Overall, our goal is document and describe the foraging behavior and ecology of the Pacific Coast Feeding Group of Gray Whales on the Oregon Coast. For a quick recap on the details of this project read these previous posts:
During this summer season, the newest iteration of team ro”buff”stus will be heading back down to Port Orford, Oregon to try to better understand the relationship between gray whales and their mysid prey. Half the team will once again use the theodolite from the top of Graveyard Point to track gray whales foraging in Tichenor Cove, the Port of Port Orford, and the kelp beds near Mill Rocks. Meanwhile, the other half of the team will use the R/V Robustus (i.e. a tandem ocean kayak named after our study species – Eschrichtius robustus, the gray whale) to repeatedly deploy a GoPro camera at several sampling locations in Tichenor cove. We hope that by filming vertical profiles of the water column, we will be able to create an index of abundance for the mysid to describe their temporal and spatial distribution of their swarms. We’re particularly interested in the differences between mysid swarm density before and after a whale forages in an area, and how whale behaviors might change based on the relative density of the available prey.
Ready to take the R/V Robustus out for her maiden voyage in Port Orford to test some of our new equipment. photo credit: Leigh Torres
In theory, asking these questions seems simple – get in the boat, drop the camera, compare images to the whale tracklines, get an answer! In reality, this is not the case. A lot of preparatory work has been going on behind the scenes over the last six months. First, we had to decide what kind of camera to use, and decide what sort of weighted frame to build to get it to sink straight to the bottom. Then came the questions of deployment by hand versus using a downrigger,
Example A why it is a bad idea to try to sample during a diatom bloom – You can’t see anything but green.
what settings to use on the camera, how fast to send it down and bring it back up, what lens filters are needed (magenta) and other logistical concerns. (Huge thank you to our friends at ODFWMarine Reserves Program for the help and advice they provided on many of these subjects.) We spent some time in late May testing our deployment system, and quickly discovered that sampling during a diatom bloom is completely pointless because visibility is close to nil.
However, this week, we were able to test the camera in non-bloom conditions, and it works! We were able to capture images of a few small mysid swarms very near the bottom of the water column, and we didn’t need external lights to do it. We were worried that adding extra lights would artificially attract mysid to the camera, and bias our measurements, as well as potentially disturbing the whale’s foraging behavior. (Its also a relief because diving lights are expensive, and would have been one more logistical thing that could go wrong. General advice: Always follow the KISS method when designing a project – keep it simple, ——!)
This image is taken at a depth of ~10 meters, with no color corrective filter on the lens – notice how blurry the mysid are.This is empty water, in the mid water columnMuch clearer Mysid! This time with a magenta filter on the lens to correct the colors for us.
My advisor recently introduced me to the concept of the “7 Ps”; Proper Prior Planning Prevents Piss Poor Performance. To our knowledge, we are the first group to try to use GoPro cameras to study the spatial and temporal patterns of zooplankton aggregations. With new technology comes new opportunities, but we have to be systematic and creative in how we use them. Trial and error is an integral part of developing new methods – to find the best technique, and so that our work can be replicated by others. Now that we know the GoPro/Kayak set-up is capable of capturing useable imagery, we need to develop a protocol for how to process and quantify the images, but that’s a work in progress and can wait for another blog post. Proper planning also includes checking last year’s equipment to make sure everything is running smoothly, installing needed computer programs on the new field laptop, editing sampling protocols to reflect things that worked well last year, and expanding the troubleshooting appendixes so that we have a quick reference guide for when things go wrong in the field. I am sure that we will run into more weird problems like last year’s “Chinese land whale”, but I also know that we would have many more difficulties if we had not been planning this field effort for the last several months.
Planning our sampling pattern in Tichenor Cove.
Team Ro”buff”stus is from all over the place this year – we will have members from Oregon, North Carolina and Michigan – and we are all meeting for the first time this week. The next two weeks are going to be a whirlwind of introductions, team bonding, and learning how to communicate effectively while using the theodolite, our various computer programs, GoPro, Kayak, and more! We will keep the blog updated with our progress, and each team member will post at least once over the course of the summer. Wish us luck as we watch for whales, and feel free to join in the fun on pretty much any cliff-side in Oregon (as long as you’ve got a kelp bed nearby, chances are you’ll see them!)
Over the past few months I have been slowly (and I do mean SLOWLY – I don’t believe I’ve struggled this much with learning a new skill in a long, long time) learning how to work in “R”. For those unfamiliar with why a simple letter might cause me so much trouble, R is a programming language and free software environment suitable for statistical computing and graphing.
My goal lately has been to interpolate my whale tracklines (i.e. smooth out the gaps where we missed a whale’s surfacing by inserting artificial locations). In order to do this I needed to know (1) How long does a gap between fixes need to be to identify a missed surfacing? (2) How many artificial points should be used to fill a given gap?
The best way to answer these queries was to look at a distribution of all of the time steps between fixes. I started by importing my dataset – the latitude and longitude, date, time, and unique whale identifier for each point (over 5000 of them) we recorded last summer. I converted the locations into x & y coordinates, adjusted the date and time stamp into the proper format, and used the package adehabitatLT to calculate the difference in times between each fix. A package known as ggplot2 was useful for creating exploratory histograms – but my data was incredibly skewed (Fig 1)! It appeared that the majority of our fixes happened less than a minute apart from each other. When you recall that gray whales typically take 3-4 short breathes at the surface between dives, this starts to make a lot of sense, but we had anticipated a bimodal distribution with two peaks: one for the quick surfacings, and one for the surfacings between 4-5 minutes dives. Where was this second peak?
Fig. 1. Histogram of the difference in time (in seconds on x-axis) between whale fixes.
Sometimes, calculating the logarithm of one of your axes can help tease out more patterns in your data – particularly in a heavily skewed distribution like Fig. 1. When I logged the time interval data, our expected bimodal distribution pattern became evident (Fig. 2). And, when I back-calculate from the center of the two peaks we see that the first peak occurs at less than 20 seconds (e^2.5 = 18 secs) representing the short, shallow blow intervals, or interventilation dives, and that the second peak of dives spans ~2.5 minutes to ~5 minutes (e^4.9 = 134 secs, e^5.7 = 298 secs). Reassuringly, these dive intervals are in agreement with the findings of Stelle et al. (2008) who described the mean interval between blows as 15.4 ± 4.73 seconds, and overall dives ranging from 8 seconds to 11 minutes.
Fig. 2. Histogram of the log of time difference between whale fixes.
So, now that we know what the typical dive patterns in this dataset are, the trick was to write a code that would look through each trackline, and identify gaps of greater than 5 minutes. Then, the code calculates how many artificial points to create to fill the gap, and where to put them.
Fig. 3. A check in my code to make sure the artificial points are being plotted correctly. The blue points are the originals, and the red ones are new.
One of the most frustrating parts of this adventure for me has been understanding the syntax of the R language. I know what calculations or comparisons I want to make with my dataset, but translating my thoughts into syntax for the computer to understand has not been easy. With error messages such as:
Error in match.names(clabs, names(xi)) :
names do not match previous names
Solution: I had to go line by line and verify that every single variable name matched, but turned out it was a capital letter in the wrong place throwing the error!
Error in as.POSIXct.default(time1) :
do not know how to convert ‘time1’ to class “POSIXct”
Solution: a weird case where the data was in the correct time format, but not being recognized, so I had to re-import the dataset as a different file format.
Error in data.frame(Whale.ID = Whale.ID, Site = Site, Latitude = Latitude, : arguments imply differing number of rows: 0, 2, 1
Solution: HELP! Yet to be solved….
Is it any wonder that when a friend asks how I am doing, my answer is “R is kicking my butt!”?
Science is a collaborative effort, where we build on the work of researchers who came before us. Rachael, a wonderful post-doc in the GEMM Lab, had already tackled this time-based interpolation problem earlier in the year working with albatross tracks. She graciously allowed me to build on her previous R code and tweak it for my own purposes. Two weeks ago, I was proud because I thought I had the code working – all that I needed to do was adjust the time interval we were looking for, and I could be off to the rest of my analysis! However, this weekend, the code has decided it doesn’t work with any interval except 6 minutes, and I am lost.
But sometimes, when you’ve been staring at the problem for hours, what you really need is a little praise for trying your best. So, if you are an R user, go download this package: praise, load the library, and type praise() into your console. You won’t regret it (See Fig. 4).
Fig. 4. A little compliment goes a long way to solving a headache.
Thank you to Rachael who created the code in the first place, thanks to Solene who helped me trouble shoot, thanks to Amanda for moral support. Go GEMM Lab!
Why do pirates have a hard time learning the alphabet? It’s not because they love aaaR so much, it’s because they get stuck at “c”!
Stelle, L. L., W. M. Megill, and M. R. Kinzel. 2008. Activity budget and diving behavior of gray whales (Eschrichtius robustus) in feeding grounds off coastal British Columbia. Marine mammal science 24:462-478.
Happy Spring everyone! You may be wondering where the gray whale updates have been all winter – and while I haven’t migrated south to Baja California with them, I have spent many hours in the GEMM Lab processing data, and categorizing photos.
You may recall that one of my base questions for this project is:
Do individual whales have different foraging strategies?
In order to answer this question, we must be able to tell individual gray whales apart. Scientists have many methods for recognizing individuals of different species using tags and bands, taking biopsy samples for DNA analysis, and more. But the method we’re using for this project is perhaps the simplest: Photo-Identification, which relies on the unique markings on individual animals, like fingerprints. All you need is a camera and rather a lot of patience.
Bottlenose dolphins were some of the first cetaceans to be documented by photo-identification. Individuals are identified by knicks and notches in their fins. Humpback whales are comparatively easy to identify – the bold black and white patterns on the underside of their frequently displayed flukes are compared. Orcas, one of the most beloved species of cetaceans, are recognized thanks to their saddle patches – again, unique to each individual. Did you know that the coloration and shape of those patches is actually indicative of the different ecotypes of Orca around the world? Check out this beautiful poster by Uko Gorter to see!
Gray whale photo identification is a bit more subtle since these whales don’t have dorsal fins and do not show the undersides of their fluke regularly. Because gray whales can have very different patterns on either side of their body, it is also important to get photos of both their right and left sides, as well as the fluke, to be sure of recognizing an individual if it comes around again. When taking photos of a gray whale, it’s a good idea to include the dorsal hump, where the knuckles start as it dives, as an easy indicator of which side of the body you are looking at when you’re trying to match photos. Some clues that I often use when identifying an individual include the placement of barnacles, and patterns of pigmentation and scars. You can see that patience and a talent for pattern recognition come in handy for this sort of work.
While we were in the field, it was important for my team to quickly find reference features to make sure we were always tracking the same whale. If you stopped by to visit our field station, you may have heard use saying things like “68 has white on both fluke-tips”, “70 has a propeller scar on the left side”, “the barnacles on 54’s head looks like a polyp”, or “27 has a smiley face in front of the first knuckle left side.” Sometimes, if a trait was particularly obvious, and the whale visited our field station more than once, we would give them a name to help us remember them. These notes were often (but to my frustration, not always!) recorded in our field notebook, and have come in handy this winter as I have systematically gone through the 8000+ photos we took last summer, identifying each individual, and noting whenever one was a repeat visitor. With these individuals labeled, I can now assess their level of behavioral and distribution consistency within and between study sites, and over the course of the summer.
Why don’t you try your luck? How many individuals are in this photoset? How many repeats? If I tell you that my team named some of these whales Mitosis, Smiley, Ninja and Keyboard can you figure out which ones they are?
#1#2#3#4#5#6#7#8#9#10
Keep scrolling for the answer key ( I don’t want to spoil it too easily!)
Answers:
There are 7 whales in this photoset. Smiley and Keyboard both have repeat shots for you to find, and Smiley even shows off both left and right sides.
Whale 18 – Mitosis
Whale 70 -Keyboard
Whale 23 -Smiley
Whale 68 – Keyboard
Whale 27 -Smiley
Whale 67
Whale 36 -Ninja
Whale 60 – “60”
Whale 38 – has no nickname even if we’ve seen it 8 times! Have any suggestions? leave it in the comments!
You must be logged in to post a comment.