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Pollution and Fishing Threats to Marbled Murrelets 



D. Michael Fry 1 



Abstract: The principal pollutant threats to Marbled Murrelets 

 are chlorinated organic effluent discharges from chlorine bleach 

 pulp mills located in California, Washington, and British Colum- 

 bia. The distribution of murrelets away from riverine input of 

 agricultural chemicals reduces the threat from these pollutants. 

 Plastic ingestion does not appear to pose a serious threat to 

 murrelets, as it does for other species of small alcids. Significant 

 threats from oil pollution are present because of heavy oil tanker, 

 commercial shipping, and barge traffic along the Pacific coast. 

 Commercial fishing threats have been significantly reduced in 

 California, Oregon, and Washington because of regulation and 

 banning of gill-net fisheries, but thousands of murrelets are still 

 killed annually in Alaska. 



Persistent organochlorine pollutants in the environment 

 are represented by pesticides, herbicides, polychlorinated 

 biphenyls (PCB), and pulp mill discharges containing 

 polychlorinated dibenzo-dioxins (PCDD) and polychlorinated 

 dibenzo-furans (PCDF). Organochlorine pesticide use has 

 been reduced during the past two decades, with the prohibition 

 of use of DDT. dieldrin, kepone, and chlordane in the United 

 States and Canada, although methoxychlor and dicofol 

 continue to be used in selected agricultural areas. The 

 herbicides 2,4-D and 2,4,5-T were used extensively in 

 reforestation projects in the Pacific Northwest, and 2,4-D 

 continues to be used. 2.4-D poses a potential risk because of 

 the presence of PCDD as contaminants of manufacture and 

 incineration product after burning of clearcut slash piles. 

 Within the range of Marbled Murrelets, PCDD and PCDF 

 represent the most prevalent pollutant risk. 



Point Sources of Organochlorine 

 Pollutants 



Kraft Pulp Mills 



Bleached paper grade pulp mills using chlorine bleaches 

 have a wide distribution along the Pacific coast of North 

 America (fig. 1), with two mills in southeastern Alaska, eleven 

 in coastal British Columbia, seven in Washington State, four 

 in Oregon and three in coastal California (Colodey and Wells 

 1992). The chlorine bleach process extracts pigmented plant 

 lignins. and produces chlorinated effluents containing dioxins 

 and furans which have been discharged to the environment at 

 levels resulting in significant injury to fisheries, birds (Great 

 Blue Herons [Ardea herodias], cormorants, and grebes), and 

 estuarine environments (Colodey and Wells 1992, Elliott and 



others 1989, Whitehead 1989, Whitehead and others 1991). 

 The PCDD and PCDF bioaccumulate in the sediments, fish 

 populations, and in fish-eating birds, causing reproductive 

 impairments in bird populations with reduced breeding success, 

 as well as malformations and embryo mortality in Great Blue 

 Herons (Bellward and others 1990, Elliott and others 1989, 

 Hart and others 1990). No specific residues or breeding 

 impairment have been identified in Marbled Murrelets, but 

 murrelets feeding locally in the areas of historic effluent 

 discharge would be at risk of exposure through bioaccumulation 

 in forage fish. In a study of coastal aquatic birds in British 

 Columbia, Whitehead and others (1991) found the highest 

 levels of dioxins in Western Grebes, which have a prey base 



1 Research Physiologist, Department of Avian Sciences, University of 

 California. Davis. CA 95616 



Figure 1 Distribution of paper grade pulp mills active or recently 

 closed which discharge chlorinated organic into estuarine environ- 

 ments on the Pacific Coast of North America. 



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



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