Acknowledgments 



I am indebted to Ned Doughty, owner and op- 

 erator of the C&D Seafood Company, Oyster, Va., 

 who made available his daily surf clam landing 

 and meat yield data for 1974 and 1975. Also, I 

 acknowledge the aid of Charles R. Muirhead, 

 Chief, Oceanographic Surveys Branch, NOAA, 

 who supplied the monthly mean seawater temper- 

 ature data for Kiptopeke Beach, Va., prior to its 

 publication. 



Literature Cited 



BARKER, A. M., AND A. S. MERRILL. 



1967. Total solids and length-weight relationship of the 

 surf clam, Spisula solidissima. Proc. Natl. Shellfish. As- 

 soc. 57:90-94. 



Bartlett, M. S. 



1949. Fitting a straight line when both variables are sub- 

 ject to error. Biometrics 5:207-212. 

 JOLICOEUR, P. 



1975. Linear regressions in fishery research: Some com- 

 ments. J. Fish. Res. Board Can. 31:1491-1494. 

 MORAN, P. A. P. 



1971. Estimating structural and functional relation- 

 ships. J. Multivariate Anal. 1:232-255. 

 RICKER, W. E. 



1973. Linear regressions in fishery research. J. Fish. 



Res. Board Can. 30:409-434. 

 1975. A note concerning Professor Jolicoeur's comments. 

 J. Fish. Res. Board Can. 32:1494-1498. 

 ROPES, J. W. 



1968. Reproductive cycle of the surf clam, Spisula solidis- 

 sima, in offshore New Jersey. Biol. Bull. (Woods Hole) 

 135:349-365. 



WALD, A. 



1940. The fitting of straight lines if both variables are 

 subject to error. Ann. Math. Stat. 11:284-300. 



JOSEPH G. LOESCH 



Virginia Institute of Marine Science 

 Gloucester Point, VA 23062 



MERCURY IN FISH AND SHELLFISH OF 



THE NORTHEAST PACIFIC. 



III. SPINY DOGFISH, SQUALUS ACANTHIAS 



The spiny dogfish, Squalus acanthias Linnaeus, is 

 a small shark that is abundant in the northeast 

 Pacific and has been utilized both as a food fish and 

 as a source of industrial fishery products. This 

 species was heavily harvested in the 1940's for the 

 high vitamin A content in the liver oil until the 

 population was significantly reduced (Alverson 



and Stansby 1963). The declining resource, along 

 with the availability and low cost of synthetic vi- 

 tamin A, led to the collapse of the fishery in the 

 early 1950's. Since that time the dogfish popula- 

 tion has significantly increased, but the low 

 economic value of the species precluded develop- 

 ment of any substantial fishery. 



Another limiting factor in commercial handling 

 of dogfish is its rather rapid deterioration. Stansby 

 et al. (1968) found that rancidity, not bacterial 

 spoilage, was the principal factor limiting the ice- 

 storage life of dogfish. If dogfish are properly iced 

 and handled quickly, off flavors due to rancidity 

 and the breakdown products of urea are 

 minimized, and they can be used as food. 



Recently there has been a renewed interest in 

 commercial exploitation of this species in Puget 

 Sound, primarily because of the export demand 

 and increased price for frozen dogfish fillets and 

 bellyflaps in Europe. In 1975 only 0.43 million lb of 

 dogfish were landed in the State of Washington for 

 both food and reduction purposes, in contrast to 4.9 

 million lb landed during 1976 in Puget Sound 

 ports 1 and processed for export to Great Britain 

 and West Germany. As a result of the current 

 interest in the use of Puget Sound dogfish as food 

 and the mercury levels in relation to import regu- 

 lations of various countries, this investigation was 

 undertaken to determine the mercury levels in 

 dogfish from inland waters of the State of 

 Washington. This report summarizes our findings. 



Materials and Methods 



The specimens were obtained from commercial 

 gill net and longline catches through the coopera- 

 tion of the industry and the State of Washington 

 Department of Fisheries. They were collected from 

 the Strait of Georgia near Blaine, Wash. (Figure 

 1), and from five locations in Puget Sound: Port 

 Townsend, Port Susan, Seabeck (Hood Canal), 

 Seattle (Elliott Bay), and Tacoma (Tacoma Nar- 

 rows to Carr Inlet). Date and location of capture, 

 round weight, length, and sex were recorded for 

 each fish. Commercial buyers had established a 

 minimum acceptable length of 32 in (81.3 cm) for 

 food processing; therefore, the size distribution of 

 most samples reflected this market practice rather 

 than the normal range of lengths in the dogfish 

 population. 



'Preliminary landings data. State of Washington Department 

 of Fisheries. 



642 



