Western Fisheries Science News, January 2018 | Issue 6.1

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On March 24, 1989, the Exxon Valdez—an oil tanker bound for Long Beach, California— struck Bligh Reef and spilled 10.8 million gallons of crude oil into Prince William Sound, Alaska. Timing of the spill coincided with the annual immigration of adult Pacific herring into the region, which were staging to spawn in areas that became inundated with oil. Herring spawned as eggs during the spill largely failed to recruit into the adult population, with 1993 representing the smallest recruitment event on record. Further, the spawning biomass underwent a massive decline (from 120,000 tons in 1989 to 30,000 tons in 1993), resulting in severe curtailment of commercial fishing. Unfortunately, the herring stock never recovered after this catastrophic event, with fewer than 10,000 tons returning in 2017.

Pacific herring play an important role in marine ecosystems of the North Pacific Ocean, providing an essential source of food for larger fish, seabirds, and marine mammals. Herring are also economically important, commercially fished for food and bait. Maintaining a healthy herring population is critical for ensuring a balanced marine ecosystem. Owing to the failure of this stock to rebound after more than 25 years, and the ecological importance of Pacific herring, the Exxon Valdez Oil Spill Trustee Council initiated an ambitious multidisciplinary effort to restore the injured herring resources. A team of scientists, including a representative from USGS (Western Fisheries Research Center’s (WFRC’s) Marrowstone Marine Field Station (MMFS), was charged with designing a 20-year Integrated Herring Restoration Plan (IHRP) to better understand chemical, physical, and biological processes that control herring abundance and recruitment. The Plan extends across scientific disciplines and institutional boundaries to include scientific partners from numerous federal departments and agencies, universities, and non-profit institutions throughout the United States and Canada.    

In response to the goals and objectives identified in the IHRP, a Herring Research and Monitoring Program (HRMP) was funded by the Exxon Valdez Oil Spill Trustee Council.  A Herring Disease Program is a major component of this HRMP and is led by researchers at the WFRC’s MMFS. Their research has been investigating the role of disease in herring populations, including the effect of oil from the spill on the immune system of herring and their subsequent resistance to endemic pathogens. Because of the unique facility attributes at the MMFS, scientists are able to safely and responsibly perform experiments related to disease to better understand population threats and declines.

For example, recent research in the Herring Disease Program has been focused on forecasting disease potential in Pacific herring. Enumerating levels of natural mortality in marine fish populations remains difficult for fishery managers who need to provide annual forecasts of population size. Although some percentage of fish die from predation, disease, and starvation, the relative contributions of these natural mortality factors is somewhat unpredictable and can change dramatically from year-to-year. Scientists are developing a novel quantitative technique (plaque neutralization test - PNT) to address the annual contribution of disease mortality to Pacific herring populations. This technique is capable of proactively forecasting disease potential in a population and retroactively deducing whether a disease epizootic may have occurred. Preliminary results indicate that viral hemorrhagic septicemia virus antibody levels often differ in herring between Prince William Sound and Sitka Sound.

This unique ecosystem-level approach, led by the Exxon Valdez Oil Spill Trustee Council, has advanced society’s scientific understanding of ecosystem-level impacts beyond anything that could have been accomplished by a single research entity. Taking this long-term approach to understanding the marine species, ecosystem, and its recovery will benefit us in the future, aiding scientists and governments around the world in responding to other oil spills and other marine disasters.

Newsletter Author: Rachel Reagan

Events

USGS Scientist Presents Monthly Lecture at Science on Tap: On January 29, 2017, USGS WFRC scientist Carl Ostberg presented a talk “Fishing for environmental DNA (eDNA): a new frontier for detecting and monitoring aquatic species” at the public seminar series Science on Tap, Ravenna Third Place Bookstore. The presentation provided a summary of eDNA as tool for use in resource management and provided examples of how eDNA based methods are used for monitoring species.

Publications

Describes Isolation and Characterization of a Virus in Salmon:

Makhsous, N., N.L. Jensen, K.H. Haman, W.N. Batts, K.R. Jerome, J.R. Winton, and A.L. Greninger. 2017. Isolation and characterization of the fall Chinook aquareovirus. Virol. J. 14: 170.

Explores Virus in Northern Pike Fry:

Getchell, R.G., E.R. Cornwell, S. Bogdanowicz, J. Andrés, W.N. Batts, G. Kurath, R. Breyta, J.G. Choi, J.M. Farrell, and P.R. Bowser. 2017. Complete sequences of 4 viral hemorrhagic septicemia virus IVb isolates and their virulence in northern pike fry. Dis. Aquat. Org. 126(3): 211-227. DOI: 10.3354/dao03171.

Describes Resource Exploitation by Juvenile Chinook Salmon in a Restored Estuarine Habitat:

Davis, M.J., C.S. Ellings, I. Woo, S. Hodgson, K. Larsen, and G. Nakai. Early View. Gauging resource exploitation by juvenile Chinook salmon (Oncorhynchus tshawytscha) in restoring estuarine habitat. Restor. Ecol. 26(5): 976-986.

Relates River Discharge and Water Temperature to White Sturgeon Recruitment:

Counihan, T.D. and C.G. Chapman. Early View. Relating river discharge and water temperature to the recruitment of age-0 White Sturgeon (Acipenser transmontanus Richardson, 1836) in the Columbia River using over-dispersed catch data. J. Appl. Ichthyol. 2018;00:1-11.

Examines Coho Salmon Growth Rates:

Manhard, C.V., N.A. Som, R.W. Perry, and J.M. Plumb. A laboratory-calibrated model of coho salmon growth with utility for ecological analyses. Can. J. Fish. Aquat. Sci. 75(5): 682-690.

Explores Fish Monitoring Programs in Large Rivers:

Counihan,T.D., I.R. Waite, A.F. Casper, D.L. Ward, J.S. Sauer, E.R. Irwin, C.G. Chapman, B.S. Ickes, C.P. Paukert, J.J. Kosovich, and J.M. Bayer. 2018. Can data from disparate long-term fish monitoring programs be used to increase our understanding of regional and continental trends in large river assemblages? PLoS ONE 13(1): e0191472.