Monitoring a Changing Environment
Many factors, both natural and human-caused, affect populations of fish, crab and marine mammals and marine ecosystems. Understanding and predicting the health and productivity of marine ecosystems informs sustainable development.
In the laboratory and in the field, Center scientists broke new ground in understanding more about Alaska ecosystems and how a changing marine environment may affect marine species. Having information like this at the ready enables policymakers and decision-makers to identify ways to sustain these valuable resources while capitalizing on the economic opportunities derived from them.
Monitoring the Eastern Bering Sea Ecosystem
The Alaska Fisheries Science Center helped provide the science to support development of a Fishery Ecosystem Plan for the Eastern Bering Sea, and a first draft of an Ecosystem-Based Fishery Management Roadmap, as part of a national effort to better define and plan our research and data priorities. Center staff conducted a number of ecosystem research
surveys in 2017. Ecosystem information is also incorporated into individual species stock assessment and fishery evaluation reports, which are used by the council to determine annual management measures for Alaska fisheries.
Assessing Impacts of Changing Ice Conditions on Eastern Bering Sea Ecosystem
The eastern Bering Sea is home to some of the nation’s largest groundfish and crab fisheries and is a migratory highway for protected marine mammals and seabirds. The productivity of this area and the distribution of fishes are driven, in part, by the temporary presence of sea ice in the winter and early spring. Climate variability has been altering the southerly extent and thickness of that sea ice. Changes in sea ice distribution, advection of warmer waters from the Gulf of Alaska, and atmospheric conditions have contributed to extended periods of time (e.g., multiple consecutive years) when water temperature are either warmer than average or colder than average (e.g., 2014-2016). This affects fish and crabs distribution.
This past year, we conducted a bottom trawl survey north of where our traditional assessment survey ends. We spent roughly three weeks on two charter vessels collecting data from approx. 60° N all the way to Bering Strait. The last time this northern area was sampled by the Center was in 2010. We saw dramatic shifts in distributions of some fish and crabs compared to 2010 when the waters were colder because the sea ice extended further into the area and stayed longer.
Predicting the Size of Future Fish Stocks through Monitoring and Modelling
We regularly collect data on environmental conditions and larval and juvenile fish abundance and biomass (combined average weight of all fish in a population). Knowing how many larval fish are produced each year, what environmental conditions are necessary for them to grow and survive to become one, two and three year old fish helps us gain insights into how well fish stocks will do in the future. For example, from 2014-2016 there were very few larval and age-0 Pacific cod seen in our surveys. The young fish that were seen were not in the places with optimal environmental conditions for growth, so few survived. This information helped resource managers better understand why the adult population of Pacific cod in the Gulf of Alaska numbers and biomass were so low in 2017.
We entered our third year of a three-year climate-modeling project (the Alaska Climate Project or ACLIM). This multi disciplinary project combines physical oceanography and fisheries science to project what the Bering Sea ecosystem will look like under different climate and fishing scenarios. This information will be valuable to resource managers in making decisions about how best to maximize fish production in the future.
Impacts of Arctic Oil Spills on Arctic Fish
Scientists in our Newport, Oregon laboratory successfully raised Arctic and Saffron cod larvae to better understand how climate variability and loss of arctic sea ice could impact arctic food webs. In collaboration with the Northwest Fisheries Science Center, Alaska Fisheries Science Center scientists briefly exposed arctic cod larvae to very tiny droplets of North Slope crude oil for short periods of time. Delivery of minute doses of oil to the fish rearing tanks was made possible using a very sophisticated device developed in Norway by SINTEF, the largest independent research organization in Scandinavia (Stiftelsen for industriell og teknisk forskning). Scientists were successful in demonstrating morphological and physiological damage to larval fish hearts during the very first series of experiments. Experiments are continuing to better understand the full impact of oil exposure to early life history stages of arctic fishes.
Integrated Ecosystem Research Implemented
The U.S. arctic ecosystems are the least studied of all the large marine ecosystems in the U.S. Exclusive Economic Zone. Alaska Fisheries Science Center researchers are collaborating with university, federal, and Alaska state partners in two arctic research programs: the Arctic Integrated Ecosystem Research Program, sponsored in part by the North Pacific Research Board and the U.S. Bureau of Ocean Energy Management and the Distributed Biological Observatory sponsored by NOAA’s Arctic Research Program. Surveys were carried out in 2017 in the northern Bering and Chukchi Seas, along the Chukchi Sea shelf Arctic basin to investigate distributions and abundance of phytoplankton, zooplankton, larval fish, small pelagic fishes, benthic fishes and invertebrates. The ultimate goal is to advance our understanding of the physical, chemical, and biological processes that structure marine food webs in the northern Bering, Chukchi and Beaufort seas. During the Arctic Integrated Ecosystem Research Program, several upward looking fish echosounder moorings were also deployed to measure fish abundance and behavior over the winter in the northern Bering Sea and Chukchi Sea when the area is inaccessible to most research vessels. All of these efforts will help us learn more about the Arctic marine environment and better time our survey efforts to capture needed biological and ecological information.
Our scientists also spent 56 days surveying the Gulf of Alaska to understand the impact of climate variability on ecosystem function and fish distribution and fitness (growth and survival). Targeted fish species include walleye pollock, Pacific cod, rockfish, sablefish, arrowtooth flounder, Pacific salmon, herring and capelin.
22nd Ecosystem Report: Alaska Marine Ecosystem Considerations
Each year, the center assembles a comprehensive report of research conducted by academic and government scientists, Alaska Marine Ecosystem Considerations. This research provides a picture of the health and productivity of distinct large marine ecosystems by monitoring various indicators (e.g., temperature, lower trophic level biomass, biomass of forage fishes, changes in current patterns that transport fish and crab larvae, and unusual phenomena such as coccolithophore blooms), generating a “report card” of indicator condition. This report and other efforts by Center scientists to develop integrated ecosystem assessments enables fisheries managers at the North Pacific Fishery Management Council to better understand and consider how changes in the environment affect the species they are managing and plan for the future to promote sustainable development.
Fisheries Models Updated to Account for Whale Depredation
Killer whales are known to “depredate” or remove fish from fishing pots, fishing lines and survey nets in Alaska. In recent years, sperm whales have also been known to engage in this behavior. Most affected are the commercial sablefish fishery and the Alaska Fisheries Science Center longline survey. Accounting for the effects of this whale depredation on the longline survey index of abundance and fishery catches for sablefish is an important research focus. In 2017 for the first time, we were able to incorporate model-derived estimates of whale depredation in both the survey and fishery into the sablefish stock assessment model.
Laboratory Studies Explore How Ocean Acidification may Impact Commercially Important Fish and Crab Stocks
Ongoing studies by scientists at our Kodiak and Newport laboratories are exploring how declining pH levels in Alaskan waters or ocean acidification will affect commercially important crab and fish species. For crabs, more acidic conditions makes it difficult for them to make shells so fewer crabs make it to adulthood. Scientists are exploring whether it is possible for crabs to adapt to changes in pH over time. Lab tests have shown that some crabs survive at lower pH levels. Experimental data on the impacts of ocean acidification on individual commercial species is also used to better understand and predict future mitigation efforts. For example, knowing the impact of OA on individual species, we can calculate the economic and food security impact that OA will have on particular coastal communities that are marine resource dependent.
Distinguished Career Award
Ann Matarese, Resource Assessment and Conservation Engineering Division, was awarded a Distinguished Career Award for Scientific Achievement, for achievement in life history research that provided foundational knowledge for ecosystem approaches to management.
NOAA Office of Oceanic and Atmospheric Research Best Papers – 2017
Tom Hurst, Resource Assessment and Conservation Engineering Division, received an OAR Outstanding Paper Award as a co-author on a paper demonstrating the value of combining physical and social sciences.
Mathis, J.T., S. R. Cooley, N. Lucey, S. Colt, J. Ekstrom, T. Hurst, C. Hauri, W. Evans, J. N Cross, and R. A. Feely. (2015) Ocean Acidification Risk Assessment for Alaska’s Fishery Sector. Process in Oceanography. 136, 71-91. DOI: 10.1016/j.pocean.2014.07.001