Fry 



Chapter 25 



Pollution and Fishing Threats 



Rican. California, 1984; ARCO Anchorage, Washington, 

 1985; and Apex Houston, California, 1986 (Bayer 1988, 

 Burger and Fry 1993, Kittle and others 1987; Page and 

 others 1990, Point Reyes Bird Observatory 1985). Mortality 

 estimates of larger numbers have been made for recent spills, 

 extrapolating from recovery experiments which demonstrate 

 that fewer than 10 percent of oiled murrelets are likely to be 

 recovered after spills, because of their small size, likelihood 

 of scavenging by predators, and other factors (ECI 1991). 

 About 170-200 murrelets were estimated to have been oiled 

 following the Nestucca spill, Washington, 1989 (Burger 

 1990: Rodway and others 1989, 1992), and approximately 

 8.400 killed after the Exxon Valdez, Alaska, 1989 (Piatt and 

 Naslund. this volume), representing approximately 3.4 percent 

 of the Alaska population. About 45 Marbled Murrelet 

 carcasses were recovered following the Tenyo Maru spill, 

 Washington 1992 (U.S. Fish and Wildlife Service, Ecological 

 Sen ices. Olympia. Washington). 



Continuing threats to murrelets from oil pollution vary 

 among different areas of the Pacific coast, in direct proportion 

 to the probability of an oil spill and the local murrelet 

 population vulnerability. 



Three areas of Alaska have significant vulnerability: 

 Lower Cook Inlet, Prince William Sound, and the Alexander 

 Archipelago. Lower Cook Inlet receives the majority of 

 cargo shipping traffic within the state. Offshore oil deposits 

 within Cook Inlet have recently been discovered which could 

 be developed within 10 years. Prince William Sound has a 

 very high density of murrelets and transits up to 700,000,000 

 bbl of crude oil annually from the pipeline terminal at Valdez. 

 The Alexander Archipelago in Southeast Alaska supports 

 the largest population of murrelets in the state (> 180,000; 57 

 percent of total population)(Piatt and Naslund, this volume), 

 and has a large number of ship transits, including fishing, 

 cargo, and passenger vessels. 



Threats from oil pollution in British Columbia appear to 

 be highest around Vancouver Island, because of the 

 coincidence of tanker and barge traffic through the Strait of 

 Juan de Fuca and high populations of murrelets on the west 

 side of the island. Murrelets in lower densities also breed in 

 the Queen Charlotte Islands, but ship traffic and tanker 

 traffic are less. The very large volume of crude oil traffic 

 from Alaska to California occurs more than 100 km offshore, 

 reducing the threat from tanker spills. 



The smaller populations of murrelets in Washington in 

 the Strait of Juan de Fuca remain at considerable risk because 

 of both tanker traffic and large volumes of commercial 

 shipping (cargo and fishing) into Seattle, Tacoma, and 

 Vancouver. The local, inshore distribution of murrelets makes 

 them particularly vulnerable to spills in coastal areas. 



Tanker and barge traffic in coastal waters of California, 

 Oregon, and Washington pose significant threats to murrelets. 

 Barges are used to enter smaller ports, and are often towed in 

 near-shore waters. While the tonnage of oil transported by 

 barge is much less than that conveyed by tanker, the Apex 

 Houston (approximately 10.000 dead birds) and Nestucca 



(>50,000 dead birds) spills have demonstrated barge traffic to 

 be of high risk to murrelets along the Pacific coast. A potential 

 threat to the small northern California murrelet population 

 may emerge if the offshore oil reserves present off Mendocino 

 and Humboldt counties are developed following the possible 

 end to a federal moratorium on drilling after year 2002. 



Commercial Fishing Threats 



Relatively large numbers of Marbled Murrelets have been 

 recorded killed in gill-nets in British Columbia and Alaska 

 (Carter and others, this volume; Carter and Sealy 1984; 

 DeGange and others 1993; Mendenhall 1992; Piatt and 

 Naslund, this volume; Wynne and others 1991, 1992), with 

 smaller numbers caught in Washington (Speich and Wahl 

 1989), and California (Carter and others, this volume). Recent 

 fishing closures and regulations have reduced the threats in 

 California, but significant threats continue to exist for murrelet 

 populations in Alaska, British Columbia, and Washington. 



Alaska 



Salmon gill-net bycatch of murrelets in Alaska is 

 estimated at 3,300 birds annually by Piatt and Naslund (this 

 volume), based upon observer program data of Wynne and 

 others ( 1 99 1 , 1 992), and extrapolations using current fishing 

 permit and fishing effort data. The approximate distribution 

 of murrelet mortality is: Lower Cook Inlet, 1,100 birds; 

 Prince William Sound, 1,000; Alaska Peninsula, 300; and 

 Southeast Alaska 900; these were primarily Marbled 

 Murrelets, and the vast majority being adults. This total of 

 3,300 birds represents approximately 1 .7 percent of the Alaska 

 population killed on an annual basis in the drift-net fishery. 

 The set-net, pound-net, and seine-net fisheries may also 

 contribute to mortality, but no quantitative data are available 

 on these fisheries. 



British Columbia 



Carter and Sealy (1984) reported a large bycatch of 

 murrelets in the Barkley Sound salmon fishery in 1979- 

 1980, with approximately 4 percent (360 birds) of the local 

 Marbled Murrelet population killed that season, plus loss of 

 chicks in nests from loss of adults. The potential for a large 

 continued bycatch exists, but data are lacking, as there is not 

 a current seabird observer program. High densities of murrelets 

 and high fishing effort do not always coincide, possibly 

 minimizing the risk in some areas, but alcids and salmon 

 frequently take the same prey species (Burger, this volume 

 b). The highest population densities of murrelets occur along 

 the west coast of Vancouver Island, with lower densities 

 along the mainland coast and Queen Charlotte Islands. 



Washington 



With current information, it is not possible to determine 

 the extent of mortality on Marbled Murrelets in Washington. 

 The salmon fishery in Washington has declined in recent 

 years, and may pose much less risk to murrelets than in 



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



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