Abstract.— Exposure of devel- 

 oping pollock Theragra chalcogram- 

 )na embryos to static water-soluble 

 fractions"(WSF)of Cook Inlet crude 

 oil in seawater slowed initial develop- 

 ment, produced shorter larvae, and 

 caused morphological abnormalities 

 including membranous vesicles; body 

 curvatures; deformations of yolk, 

 eye, brain, jaw, intestine, and peri- 

 cardial sac; absence of lower jaw; fin 

 erosion; yolksac bloating; and light 

 pigmentation. These abnormalities 

 were retained after hatch, and in 

 many cases became more pronoiuiced 

 as developing structures failed to 

 form properly. The median concen- 

 tration of WSF that caused abnor- 

 malities (AB.r,||) was 2.1 + 0.1 ppm. 

 Exposure during embryonic develop- 

 ment reduced prehatch survival by 

 a maximum of 26%, and caused high 

 mortality after hatch. The median 

 lethal concentration (1.8 + 0.6 ppm) 

 was not significantly different than 

 the AB,-||. Although exposed pollock 

 embryos generally sur\nved to hatch- 

 ing, larvae were malformed, smaller, 

 and had poorer survival potential 

 than controls. 



Abnormal Development and 

 Growth Reductions of Pollock 

 Theragra chalcogramma Embryos 

 Exposed to Water-Soluble 

 Fractions of Oil 



Mark G. Carls 

 Stanley D. Rice 



Auke Bay Laboratory, Alaska Fisheries Science Center 

 National Marine Fisheries Service, NOAA 

 PO Box 210155, Auke Bay. Alaska 99821 



Manuscript accepted 31 August 1989. 

 Fishery Bulletin, U.S. 88:29-37. 



Early life stages of fish are ustially 

 more sensitive to environmental 

 stress than adults (Moore and Dwyer 

 1974, Rice 1985. Carls 1987). Plank- 

 tonic eggs and larvae of demersal 

 fish, such as Atlantic cod Gadus mor- 

 hua and walleye pollock Theragra 

 chalcogramma, are generally sen- 

 sitive to dissolved oil. For example, 

 prefeeding Atlantic cod larvae grew 

 significantly less than controls when 

 exposed for 2 weeks to 0.07 ppm of 

 water-soluble fractions (WSF) of 

 Ekofisk crude oil (Tilseth et al. 1984). 

 The frequency of oil spills is greatest 

 near the shore where shipping and 

 drilling activities are concentrated 

 and navigation hazards are more fre- 

 quent. For example, the oil tanker 

 Exxon Valdez grounded within 

 Prince William Sound on 23 March 

 1989 with disastrous consequences. 

 Oil spilled by drilling and transporta- 

 tion generally concentrates in the 

 surface layers and, therefore, may 

 impact nearshore areas where the 

 planktonic eggs of Atlantic cod and 

 walleye pollock are spawned (Kiihn- 

 hold 1970, Longwell 1977). 



Fish embryos respond in similar 

 ways to a broad range of stressors 

 (Rosenthal and Alderdice 1976, Lin- 

 den et al. 1980), including the WSF 

 of crude oils. Most sublethal effects 

 are probably biochemical in origin, 

 and include morphological abnormal- 



ities and reductions in growth (Rosen- 

 thal and Alderdice 1976). 



In this study we measured the ef- 

 fects of exposure to WSF hydrocar- 

 bons on the growth and development 

 of pelagic marine walleye pollock 

 eggs. Walleye pollock is an abundant 

 species in the North Pacific Ocean 

 and comprises 20-50% of the total 

 fish biomass in the Bering Sea (Smith 

 1981). Pollock are ecologically and 

 commercially important; they are a 

 major component of the food web, 

 and the total commercial catch off 

 Alaska averaged 1,013,815 t during 

 the years of this study (1982-83) 

 (National Marine Fisheries Service 

 1982, 1983). 



Methods 



Adult walleye pollock were collected 

 by trawling in March 1982 and May 

 1983 near Juneau, Alaska. Ripe adults 

 were transported live to the Auke 

 Bay Laboratory. Each year, eggs and 

 milt were stripped from a single pair 

 and mixed in a beaker without water. 

 Eggs were then transferred at ran- 

 dom into 15 cm diameter x 20 cm tall 

 cylindrical glass jars wrapped with 

 black plastic tape and each filled with 

 2.5 L of either hydrocarbon free sea- 

 water (28.5 ppt) or seawater contam- 

 inated with the WSF of Cook Inlet 

 crude oil (Table 1). After a 2-hour 



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