BP's Deep Water Drilling Disaster
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On August 13, 2011 "tar logs" were collected by LEAN members from the shore of Ship Island off the coast of Mississippi. The tar logs, as they are being called, are brick sized globs of petroleum hydrocarbons that have been rolled into a cylindrical "log" shape by wave action. Samples of the tar logs were sent to a commercial laboratory for analysis....
EXXON VALDEZ grounded on Bligh Reef in Prince William Sound, Alaska, on
...Lesions and elevated hydrocarbon levels were documented (click title to entry - thank you) in some adult Pacific herring from the oiled areas. Laboratory studies showed abnormalities and possible depressed immune functions in Pacific herring exposed to oil. Significant adult mortality was not observed in 1989, but this would not be unexpected given the heavy predation or scavenging by different groups of predators. Egg mortalities and larval deformities were also documented in the 1989 year class, but population level effects of the spill were never clearly established.
Prior to the spill, herring populations in the Sound were increasing as documented by record harvests in the late 1980s. However, four years after the spill a dramatic collapse of the fishery occurred, and the herring population has never rebounded. Herring populations are dominated by occasional, very strong year classes that are recruited into the overall population. The 1988 pre-spill year-class of Pacific herring was large in Prince William Sound, and as a result, the estimated peak biomass of spawning adults in 1992 was high. Despite the expectation that this large spawning event would lead to high numbers of fish, the population exhibited a density-dependent reduction in size of individuals, and in 1993 there was an unprecedented crash of the adult herring population in PWS. The overall 1993 harvest was about 14 percent of the 1992 harvest, and the 1989 year class was one of the smallest cohorts ever to return as spawning adults....
