Literature Cited 



ALVERSON, D. L., AND M. E. STANSBY. 



1963. The spiny dogfish (Squalus acanthias) in the north- 

 eastern Pacific. U.S. Fish Wildl. Serv., Spec. Sci. Rep. 

 Fish. 447, 25 p. 

 CHILDS, E. A., AND J. N. GAFFKE. 



1973. Mercury content of Oregon groundfish. Fish. Bull., 

 U.S. 71:713-717. 

 CHILDS, E. A., J. N. GAFFKE, AND D. L. CRAWFORD. 



1973. Exposure of dogfish shark feti to mercury. Bull. 

 Environ. Contam. Toxicol. 9:276-280. 



FORRESTER, C. R., K. S. KETCHEN, AND C. C. WONG. 



1972. Mercury content of spiny dogfish (Squalus acan- 

 thias) in the Strait of Georgia, British Columbia. J. Fish. 

 Res. Board Can. 29:1487-1490. 

 HOLLAND, G. A. 



1957. Migration and growth of the dogfish shark, Squalus 

 acanthias (Linnaeus), of the eastern North Pacific. Wash. 

 Dep. Fish., Fish. Res. Pap. 2(11:43-59. 

 JENSEN, A. C. 



1966. Life history of the spiny dogfish. U.S. Fish Wildl. 

 Serv., Fish. Bull. 65:527-554. 

 KAUFFMAN, D. E. 



1955. Noteworthy recoveries of tagged dogfish. Wash. 

 Dep. Fish., Fish. Res. Pap. l(3):39-40. 

 MUNNS, R. K. 



1972. Mercury in fish by cold vapor AA using sulfuric- 

 nitric acid/V 2 5 digestion. Food Drug Admin. Inf. Bull. 

 1500, 8 p. 

 SCHMIDT, A. M. 



1974. Action level for mercury in fish and shellfish. Fed. 

 Regist. 39(236), Part 11:42738-42740. 



STANSBY, M. E., G. KUDO, AND A. HALL. 



1968. Chemical spoilage pattern of grayfish. Food 

 Technol. 22:765-768. 



ALICE S. HALL 



FUAD M. TEENY 



ERICH J. GAUGLITZ, JR. 



Northwest and Alaska Fisheries Center 

 National Marine Fisheries Service, NOAA 

 2725 Montlake Boulevard East 

 Seattle, WA 98112 



LOCALIZED MASS MORTALITY 



OF RED SEA URCHIN, 



STRONGYLOCENTROTUS FRANC1SCANUS, 



NEAR SANTA CRUZ, CALIFORNIA 



Johnson (1971) reported on the occurrence of a 

 mass mortality of red sea urchin, Strongylocen- 

 trotus franciseanus (Stimpson 1857) off Point 

 Loma, San Diego, in the summer of 1970, and she 

 detailed the symptoms of the diseased sea urchins. 

 Large areas of the test, particularly of the inter- 

 ambulacra, were denuded of spines and epidermis. 



These denuded areas were chalky white with 

 green blotches and often were bordered by a ring of 

 swollen tissue. The test plates of the denuded area 

 were layered and a middle "red-friable" layer with 

 disorganized cellular structure replaced the nor- 

 mal plate tissue and ossicle. In some cases, lesions 

 broke through the denuded tests and these appar- 

 ently led to the animals' death. The internal or- 

 gans appeared to be normal. Johnson (1971) was 

 unable to determine the cause of these symptoms, 

 but she suggested that a microorganism, perhaps 

 a fungus, might be responsible. 



The area affected in the 1970 mass mortality off 

 Point Loma was limited to a few hectares (Johnson 

 1971). It was first noted in May 1970, when the 

 center of the area was littered with dying sea ur- 

 chins while the perimeter had fewer diseased 

 animals with only small patches of denuded tests. 

 The affected area did not spread, and by the middle 

 of summer, many of the surviving urchins were 

 regenerating spines. Diseased animals with par- 

 tially denuded tests were difficult to find in 

 November 1970. 



We report here two other localized mass mor- 

 talities of S. franciseanus in central California, 

 which seem to be similar to the one documented by 

 Johnson (1971). One was found in 3-5 m of water 

 off the southeast side of Ano Nuevo Island (lat. 

 37°06'25"N, long. 122°19'30"W). It was first ob- 

 served on 18 July 1976, and revisited on 31 July 

 1976. Diseased animals with drooping spines and 

 partially denuded tests were found scattered 

 among healthy-appearing individuals. They did 

 not seem to be clumped or segregated, although 

 most diseased animals were in the open while 

 healthy-appearing animals tended to be under 

 ledges or in crevices. Diseased animals did not 

 hold onto the rocks as normal animals usually do, 

 and they were picked up easily by divers. Empty 

 tests of recently dead animals littered portions of 

 the bottom. Red sea urchins were the only animals 

 noted to be affected at the Ano Nuevo Island site. 

 Other areas of similar depth to the south and 

 northwest of Ano Nuevo Island supported numer- 

 ous healthy-appearing red sea urchins and none 

 with denuded tests. 



The diseased animals collected from Ano Nuevo 

 Island were very similar to those described by 

 Johnson (1971) (Figure 1). Portions of the test 

 were denuded of spines while the remainder of the 

 test was covered with normal-appearing spines. 

 The affected test plates were layered with a thin 

 greenish surface layer, a red-friable middle layer 



645 



