New and old methods in our gray whale field season 2017

By Leila Lemos, Ph.D. Student, Department of Fisheries and Wildlife, OSU

On June 6th the GEMM Lab officially started the second year of fieldwork of our “Noise Physiology” Project with gray whales along the Oregon coast. To date, we have spent 14 days at sea (12 around the Newport area and 2 in Port Orford, our control area), with a total of 32:31 hrs of effort. In 29 whale sightings of approximately 40 whales we have been able to collect 6 fecal samples for hormonal analysis, to fly the drone 17 times over the whales, to deploy a GoPro 6 times for qualitative prey analysis, and to deploy a light trap 2 times for quantitative prey analysis. While this sounds good, we have only just begun, with our field season extending into October. The graph below displays the sightings and data collection by area.

We have added a couple new components to our project this year. First, we are now using a “the light trap”, as mentioned above, to capture zooplankton prey of gray whales. The light trap (Figure 2), designed by our collaborator of Kim Bernard (OSU, College of Earth, Ocean, and Atmospheric Sciences). The light trap is composed of a water jug with a cut-out cone entrance where prey might enter the jug after being attracted by the chem lights we put in the jug. The jug is weighted down to maintain position, but swivels off the drop line by its own floats; and it’s all connected to a surface float.

The light trap is left overnight and recovered in the next day. Trapped prey are sieved (Figure 4), stored in properly labeled jars or Ziploc bags, and kept frozen until analysis (Figure 5 and 6) including species identification, community analysis, and caloric content.

The second component we have added this year is the fixed-location hydrophone (Figure 7) to record acoustic noise data over the entire summer season. Last year we used a temporarily deployed “drifting hydrophone” that only recorded noise data punctually. Because of the fixed hydrophone, this year we will be able to compare our hormone data with a wider range of acoustic data, and improve our analyses.

We also made our first trip down to Port Orford, our control area, to intensively collect data over only two days (July 5^th and 6^th). Since Port Orford is a smaller city with reduced vessel traffic, we want to evaluate if whales observed in this area show a reduced stress response when compared to the whales that inhabit the area around Newport and Depoe Bay, where vessel traffic is higher. However, we were not able to collect any fecal sample during this trip to Port Orford, so more trips south to come!

The other components we used last year such as photo identification (Figure 10), fecal samples (Figures 11 and 12), drones, and GoPros are still being put to use this year. If you want to know more about our Noise Physiology project, check here.

We are progressively spotting more gray whales along the Oregon coast and we will continue our field efforts and data collection until October. So, for now enjoy some photos taken during the last couple of months. Until next time!