Fishlines newsletter

Vol. 33, No. 8
August 2013

Alaskans—These events are for you!

Using Strontium Isotope Ratios to Track Salmon Migration in the Nushagak River

Sean BrennanPh.D. candidate Sean Brennan.

Thanks to innovative research at the University of Alaska Fairbanks, funded by Alaska Sea Grant, scientists may be able to identify the stream origin of king salmon stocks in the Nushagak River in southwestern Alaska.

Ph.D. candidate Sean Brennan, advised by professor Matthew Wooller with the School of Fisheries and Ocean Sciences, is developing a strontium isotope map to track natal origins of king salmon. By analyzing the strontium isotope composition in a fish’s otolith (ear bone), and comparing it to Nushagak tributary waters, they can identify different geographic locations in the watershed where a king salmon may have originated.

Brennan has painstakingly measured the ratio of strontium isotopes (each isotope having a different number of neutrons) in the Nushagak River and streams, and in salmon otoliths. The unique strontium isotope ratios occur naturally in the watershed and come from bedrock. The isotope ratios are incorporated into otolith rings, which are added throughout a fish’s life. These stream isotope ratio “signatures” provide researchers useful insight into where the fish have spent their time.

Brennan’s preliminary work has recognized nine different “strontium isotopic” stocks of king salmon in the Nushagak River. He and others are mapping river water chemistry in other areas of Alaska as well, with a goal of identifying salmon stocks and their origins throughout Alaska. Brennan will wrap up his research in spring 2014.

Progress Made in Marine Mammal Stranding Response

Kate WynneMarine mammal specialist Kate Wynne.

Alaska Sea Grant Marine Advisory faculty processed 188 marine mammal coastal strandings, 12 of them alive, from October 2010 to March 2013. As marine mammal specialist Kate Wynne compiled this and other facts into the final report for a NOAA Prescott Grant, MAP Response to Marine Mammal Strandings in Alaska, one event drew particular attention.

Gay Sheffield's handling of the 2011–2013 federally designated Northern Alaska Pinniped Unusual Mortality Event was reported as the project's most notable accomplishment. The disease affected all four arctic species of ice-associated seals in western and northern Alaska, eastern Russia, and western Canada. In the Bering Strait region, Sheffield, who is the Marine Advisory agent in Nome, connected subsistence harvesters with national and international biologists, pathologists, and resource managers as they attempted to identify a novel widespread disease characterized by delayed hair growth, skin sores, and lethargic seals. Working closely with the North Slope Borough Department of Wildlife Management, Eskimo Walrus Commission, and coastal communities, Sheffield provided reports, specimens, and even entire carcasses for further research.

During the event Sheffield worked long and hard to explain the unique food security and human health concerns held by Alaskans who rely on marine mammals as subsistence food, to authorities in the nation's capital. At the same time she interpreted federal issues and progress of the investigation to coastal community members in the Bering Strait region. The seal sickness remains a mystery with no infectious disease identified, but Sheffield has bridged a human gap by communicating the needs of each group that were at times frustratingly baffling to the other.

Four Marine Advisory agents were trained to respond to marine mammal strandings during the Prescott Grant project, from southeast Alaska to the Bering Strait. The calls that were responded to by all nine NMFS-approved Marine Advisory faculty included nine seal or sea lion species, five whale species, sea otters, walruses, and a green sea turtle. Agents also recruited student and public involvement in the responses, sometimes involving carcass necropsy, skeletal reconstruction, and live release.

Marine Advisory Program responders are members of a nationwide stranding network to monitor the health of marine mammals, and collect data that will be useful in long-term studies of marine ecosystems.

Oliveira Joins MAP Faculty Full Time

Alex OliveiraAssociate professor Alex Oliveira.

Alexandra Oliveira, based at the University of Alaska Fairbanks Kodiak Seafood and Marine Science Center, has joined the Alaska Sea Grant Marine Advisory faculty full time. She has been a member of the UAF School of Fisheries and Ocean Sciences faculty since 2001, where her research focuses on analytical seafood chemistry, nutritional value of seafood products, and sensory evaluation of seafood.

Oliveira will provide technical assistance to seafood processors in Alaska on processing and HACCP plans (Hazard Analysis Critical Control Point). She will become certified to teach HACCP classes to seafood processors in September 2013 and she will be part of the team teaching Better Process Control School.

This month Oliveira is gearing up to lead two Kodiak workshops, Smoking Fish for Fun and Profit, scheduled for Aug. 28–30 and Sept. 4–6.

Oliveira is chair of the Aquatic Food Products Division of the Institute of Food Technologists, and program chair of the 65th Pacific Fisheries Technologists Conference to be held in Monterrey, California, in February 2014.

Callers Appreciate Marine Policy Forum

According to a recent survey, Alaskans interested in marine policy news appreciate what they are getting from the Alaska Marine Policy Forum.

Every two months about 30 professionals—in government, commercial fishing industry, NGOs, scientists, etc.—call in to update each other on events and changes in marine policy and regulations. In July, more than 200 participants in the Alaska Marine Policy Forum, sponsored by Alaska Sea Grant and the Alaska Ocean Observing System, had an opportunity to evaluate the forum.

Of the 32 people who answered the survey, 23 percent think the calls are extremely useful and 72 percent say they are fairly useful. The favorite aspects of the call were cited as the broad scope of topics, hearing from congressional and legislative staff, and getting timely information and confirming/refuting rumors. Nearly all respondents regularly access the summary notes for each call.

Molly McCammon, AOOS director and Alaska Sea Grant Advisory Committee member, launched the Marine Policy Forum in 2009. McCammon and Alaska Sea Grant director Paula Cullenberg host the calls and develop each agenda. For more information and to participate, see the AOOS Alaska Marine Policy Forum web page.