Carter and Kuletz 



Chapter 26 



Mortality Due to Oil Pollution 



William Sound (Forsell and Gould 1981). This scenario is 

 supported by the relatively high proportion of carcasses 

 estimated as killed outside Prince William Sound (table 1), 

 compared to the relatively low numbers of murrelets which 

 breed in other areas (Piatt and Ford 1993). 



Other Impacts 



A variety of other impacts to murrelets occurred as a 

 result of the Exxon Valdez oil spill. Some murrelets were 

 sublethally oiled and probably were affected physiologically 

 after the immediate oiling event. Oakley and others (1994) 

 found evidence of compounds indicative of oil ingestion in 

 murrelets collected in 1989 in heavily-oiled areas, but not in 

 lightly-oiled or unoiled areas of Prince William Sound. 

 Murrelets also were affected in foraging areas by increased 

 human activity, associated with clean-up and monitoring 

 programs. In the summer of 1989 in Prince William Sound, 

 Exxon mobilized over 600 marine vessels and 85 aircraft 

 which logged 6,000 flight hours (Carpenter and others 1 99 1 ). 

 A reduced operation was conducted in 1990, followed by 

 minimal operations in 1991 and 1992. In 1989, repeated 

 surveys at Naked Island (in central Prince William Sound) 

 and in Kachemak Bay (in lower Cook Inlet) showed a decrease 

 in the number of murrelets with an increase in boat traffic 

 over the course of the summer (Kuletz, in press). Similarly, 

 land-based counts showed a similar relationship between 

 murrelet numbers and boat and low-flying aircraft counts 

 per hour. The Exxon Valdez was anchored at Naked Island 

 until late June 1989. This area was a staging ground for 

 clean-up and monitoring activities. Kuletz (in press) found 

 significantly fewer murrelets there in 1989, compared to 

 three pre-spill years. In 1 990- 1 992, murrelet numbers returned 

 to pre-spill levels. 



The oil spill may have impacted on forage fish populations. 

 Prey species for murrelets in south central Alaska include 

 Pacific sand lance (Ammodytes hexapterus), capelin (Mallotus 

 villosus), cod (Gadidae spp.) and juvenile Pacific herring 

 (Clupea harengus) (Kuletz, unpubl. data; Sanger 1983, 1987). 

 Seabird diet studies in Prince William Sound indicated that 

 sand lance and herring were less available in 1989 and 1990 

 than in pre-spill years (Irons 1992; Oakley and Kuletz 1994; 

 Piatt and Anderson, in press). Many prey species are intertidal 

 spawners, and are more susceptible to oil pollution than pelagic 

 spawners (Trasky and others 1977). At Naked Island, herring 

 had high levels of sublethal damage and larval malformations 

 after the spill; herring did not spawn there in 1991 (Hose and 

 others 1993). Herring returns were drastically reduced between 

 1992-1994 and adult fish have had high rates of viral infections. 

 On the other hand, there is evidence that the composition and 

 abundance of forage fish populations throughout the Gulf of 

 Alaska have changed markedly during the last 20 years (Piatt 

 and Anderson, in press). 



Marbled Murrelets may have experienced lower 

 reproductive success at Naked Island after the spill, as 

 evidenced by lower numbers of juveniles in relation to adults 

 on the water (Kuletz, in press). In contrast, the adultijuvenile 



ratio at Kachemak Bay did not change after the spill. 

 Kachemak Bay was further removed temporally and spatially 

 from the spill epicenter. The potential for disruption of 

 breeding activities in Prince William Sound was great due to 

 the potential combination of direct mortality of adults, direct 

 mortality of mates affecting surviving mates, displacement 

 from foraging areas due to human activity, sub-lethal oil 

 ingestion, and possible impacts on the prey base. 



Restoration 



Planning for restoration activities, mandated under 

 CERCLA, began in late 1989. In October 1989, under a civil 

 consent decree between Exxon and the state and federal 

 governments, Exxon agreed to make ten annual payments 

 totaling $900 million for injuries to natural resources, agency 

 service costs, and for restoration and replacement of natural 

 resources. A portion of these funds were used to lay the 

 groundwork for restoration of the injured resources. Under a 

 Memorandum of Agreement between state and federal 

 governments, the restoration funds were to be used "...for 

 the purposes of restoring, replacing, enhancing, or acquiring 

 the equivalent of natural resources injured as a result of the 

 Oil Spill...", and further, that the funds had to be spent on 

 resources in Alaska if possible. Six appointed Trustees have 

 overseen public meetings, authorization of projects, and 

 implementation of restoration programs (Exxon Valdez Oil 

 Spill Trustee Council [EVOSTC] 1994). 



Public input has been an important part of the restoration 

 process. Overwhelming public support was indicated for 

 acquisition of land to protect natural resources and promote 

 recovery. For aesthetic and recreational reasons, as well as 

 to protect commercially-important salmon resources, the 

 acquisition of forested lands has remained a high priority. 

 Few other options could be agreed upon to restore injured 

 resources within a landscape of the size and complexity of 

 the Exxon Valdez oil spill zone. By 1994, 42 percent of the 

 $100 million committed to annual work has been allocated 

 to habitat protection (EVOSTC 1994). Marbled Murrelets 

 were known to depend on old-growth forests, were impacted 

 heavily by the spill, and have become a focal species for 

 ranking lands for potential acquisition. Therefore, the Marbled 

 Murrelet Restoration Project attempted to describe their 

 nesting habitat in the spill zone (see Kuletz and others, in 

 press; Kuletz and others, this volume; Marks and others, in 

 press; Naslund and others, in press). 



Although protection of nesting habitat in old-growth 

 forests removes one future threat to murrelets, partial or full 

 recovery may not be possible until other threats are addressed. 

 For example, mortality in commercial gill-net fisheries (Carter 

 and others, this volume) and apparently high predation levels 

 also impact murrelet populations in the spill zone. 



Summary 



The Exxon Valdez oil spill made it abundantly clear that 

 oil spill prevention, response preparation, and habitat protection 

 are the best means to reduce the impact of oil pollution on 



264 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



