Correlates to survival of juvenile sea otters in Prince William Sound, Alaska, 1992–1993

2003 ◽  
Vol 81 (9) ◽  
pp. 1494-1510 ◽  
Author(s):  
B E Ballachey ◽  
J L Bodkin ◽  
S Howlin ◽  
A M Doroff ◽  
A H Rebar

We estimated survival of sea otters (Enhydra lutris) for 1 year post weaning during 1992–1993 in Prince William Sound (PWS), location of the 1989 Exxon Valdez oil spill. We sampled 38 pups in eastern PWS (EPWS), an unoiled area occupied by sea otters for <15 years, and 33 pups from oiled western PWS (WPWS), occupied for >25 years. We compared survival between areas, sexes, and condition groups. We also examined the relation of blood parameters to survival. Survival was estimated at 0.74 in EPWS and 0.52 in WPWS. Female survival was 0.86 in EPWS and 0.64 in WPWS, whereas male survival was lower, 0.61 in EPWS and 0.44 in WPWS. Sea otters from EPWS were in better condition (mass/length) than WPWS sea otters. Pups in better condition had higher survival in EPWS but not in WPWS. Foraging success was greater in EPWS than in WPWS, consistent with either an effect of length of occupation or the effects of oil on the prey base or a combination of these effects. Area differences in blood parameters suggested liver damage in WPWS sea otters, perhaps resulting from continued exposure to oil. Thus, both length of occupation and oiling history likely influenced juvenile survival in PWS.

1993 ◽  
Vol 9 (4) ◽  
pp. 343-359 ◽  
Author(s):  
Robert A. Garrott ◽  
L. Lee Eberhardt ◽  
Douglas M. Burn

PEDIATRICS ◽  
1991 ◽  
Vol 88 (3) ◽  
pp. 661-661
Author(s):  
J. F. L.

ANCHORAGE, April 20—Sea otters rescued from waters fouled by the Exxon Valdez oil spill fared poorly after their return to the wild last fall, and scientists working under Government contract say at least half may have perished over the winter. Nearly 900 dead otters were found after the tanker spilled almost 11 million gallons of crude oil in March 1989. An additional 360 were netted alive and brought to rehabilitation centers at Valdez, Seward, Homer and Kodiak. About 200 were later returned to Prince William Sound but some scientists say that as many as half may have perished and that the rehabilitation effort has been largely futile... The withholding of scientific information on the spill for legal reasons by all the parties is becoming a major source of controversy as research projects begin to generate at least preliminary data.


The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 723-737 ◽  
Author(s):  
David B. Irons ◽  
Steven J. Kendall ◽  
Wallace P. Erickson ◽  
Lyman L. McDonald ◽  
Brian K. Lance

Abstract We compared post Exxon Valdez oil-spill densities of marine birds in Prince William Sound from 1989–1991, 1993, 1996, and 1998 to pre-spill densities from 1984–1985. Post-spill densities of several species of marine birds were lower than expected in the oiled area of Prince William Sound when compared to densities in the unoiled area. These negative effects continued through 1998 for five taxa: cormorants, goldeneyes, mergansers, Pigeon Guillemot (Cepphus columba), and murres. Black Oystercatchers (Haematopus bachmani) and Harlequin Ducks (Histrionicus histrionicus) exhibited negative effects in 1990 and 1991. Loons showed a weak negative effect in 1993. Black-legged Kittiwakes (Rissa tridactyla) showed relative decreases in 1989, 1996, and 1998 which may have been caused by shifts in foraging distribution rather than declines in populations. Glaucous-winged Gulls (Larus glaucescens) showed positive effects in most post-spill years. Murrelets and terns showed relative increases in 1993, 1996, and 1998. Generally, taxa that dive for their food were negatively affected, whereas taxa that feed at the surface were not. Effects for some taxa were dependent upon the spatial scale at which they were analyzed. Movements of birds and the mosaic pattern of oiling reduced our ability to detect oil-spill effects, therefore our results may be conservative. Several marine bird species were negatively affected at the population level and have not recovered to pre-spill levels nine years after the oil spill. The reason for lack of recovery may be related to persistent oil remaining in the environment and reduced forage fish abundance.


1995 ◽  
Vol 10 (1-2) ◽  
pp. 137-156 ◽  
Author(s):  
Douglas A. Wolfe ◽  
K. John Scott ◽  
John R. Clayton ◽  
John Lunz ◽  
James R. Payne ◽  
...  

2001 ◽  
Vol 2001 (1) ◽  
pp. 569-575
Author(s):  
Ernest Brannon ◽  
Keya Collins ◽  
Lawrence Moulton ◽  
Keith R. Parker

ABSTRACT In the tenth year following the Exxon Valdez oil spill, differences of opinion still exist about injuries to pink salmon. It was alleged that exposure to oil reduced growth of fry and induced mortality in eggs. The authors reexamined the allegation that injury occurred and have concluded that insufficient consideration was given to other factors that affected results in the studies from which these allegations were drawn. The inability to track temperature differences and the unknown ages of fry precluded assessment of oil effects on growth during early marine residence. Reported higher egg mortality and long-term injury alleged to have resulted from oil exposure during incubation were confounded by the mortality of eggs that occurred as an artifact of the sampling procedure, unrelated to oil effects. The authors concluded that injury to incubating pink salmon embryos and reduced fry growth were based on an incomplete assessment of other factors that influenced these results. This evidence is supported by other research that has disclosed no oil effects on incubating eggs. Among these were studies that showed measured oil concentrations reaching the incubation substrate were 14 to 7,600 times below the lethal threshold. The seven largest runs in the history of Prince William Sound (PWS), Alaska have returned in the 10 years following the spill, which ultimately demonstrated the lack of measurable effect of the oil spill on pink salmon. The authors suggest that the allegation of oil-induced injury to PWS pink salmon needs to be reconsidered in light of these analyses.


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