Prince William Sound Herring: An updated synthesis of population declines and lack of recovery
نویسنده
چکیده
The PWS herring population collapsed 4 years after the Exxon Valdez oil spill, igniting debate about the cause. Fishermen who once depended on this stock for income and some investigators are convinced that the spill was causal, others are not. Our re-examination of the data demonstrates that polynuclear aromatic hydrocarbons (PAH) are highly toxic and that the oil spill significantly damaged herring embryos in 1989. These effects were no longer detectable after 1990 and strong recruitment of the 1988 year-class (in 1991) marked population recovery from the direct toxic effects of the spill. No plausible oil-related mechanisms have been developed to explain a delayed response after intervening years of no response. By 1993, recruitment to an expanding population (plus an additional 1 to 2% because the stock was not fished in 1989) helped precipitate a catastrophic disease outbreak. Epidemiological analysis identifies three significant risk factors for the 1993 population crash: 1) relatively large biomass from 1988 to 1992 (i.e., a susceptible host); 2) relatively low zooplankton production in 1991
منابع مشابه
&on Vuldez Oil Spill Restoration Project Final Report Investigations of Disease Factors Affecting Declines of Pacific Herring Populations in Prince William Sound Restoration Project 98162 Final Report Sections: I. Field Survey of Diseases in Prince William Sound Herring
Pacific herring (ClupeupulZasz) population biomass in Prince William Sound declined nearly 80% from 1992 to 1994. Viral hemorrhagic septicemia virus probably contributed most to population decline in 1994. Viral prevalence in spring samples (n = 233-260/year) steadily decreased from 1994 to 1996 (4.7% 1.9% O.OO/), but prevalence increased to 15% in 1997 and 1998. Vial disease is acute (days to ...
متن کاملBayesian stock assessment of Pacific herring in Prince William Sound, Alaska
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Pacific herring, Clupea pallasi, were exposed both acutely (96 h) and chronically (9 wk) to the water-soluble fraction (WSF) of North Slope crude oil. Initial mean total PAH concentrations were approximately 10, 40 and 100 μg/L. Biological availability was suggested by a significant induction of hepatic cytochrome P450 content, ethoxyresorufin O-deethylase and glutathione S-transferase activiti...
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Both the prevalence and tissue titer of viral hemorrhagic septicemia virus (VHSV) increased in Pacific herring Clupea pallasi following their introduction into net pens (pounds) used in the closed pound spawn-on-kelp (SOK) fishery in Prince William Sound, Alaska. VHSV was also found in water samples from inside and outside the SOK pounds after herring had been confined for several days; however...
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تاریخ انتشار 2007