FISHERY BULLETIN: VOL. 82, NO. 2 



predominant after 7 d. The latter is capable of 

 hydrolyzing urea, and several species of Micrococ- 

 cus are urease-positive (Buchanan and Gibbons 

 1974); hence, both of these groups are potential 

 contributors to shark tissue spoilage. This en- 

 richment of Gram positive types in elasmobranch 

 spoilage was noted by Wood (1950). 



Bacteria were found in 12 samples of shark mus- 

 cle (Scoliodon sp.) allowed to spoil at 27°-30°C 

 (Velankar and Kamasastri 1955). No coryneforms 

 and only one Micrococcus isolate were found; all 

 others were unidentified Gram negative nonpig- 

 mented rods. 



The spoilage of iced abdominal wall muscle of 

 Australian school shark, Galeorhinus australis, 

 was studied by Yap (1979). Pseudomonas and 

 Moraxella (459c and 20%, respectively) were the 

 dominant bacteria recovered after 10 d although 

 the Gram positive cocci represented 15 c /c of the 

 total. 



The data presented here for the flesh spoilage 

 experiment, albeit limited, confirm the observa- 

 tions of Wood (1950) and Yap (1979), but none of 

 these parallel the findings of Velenkar and 

 Kamasastri (1955) which also concerned sharks 

 from subtropical waters. Perhaps the local marine 

 microflora or experimental conditions influenced 

 their observations. 



Although the number of isolations was rela- 

 tively small, the genus Planococcus was found as- 

 sociated with elasmobranch skin and teeth in this 

 study. All the cultures recovered were yellow- 

 pigmented and were probably Planococcus citreus, 

 the only accepted species (Buchanan and Gibbons 

 1974). This proteolytic bacterium has been impli- 

 cated in shrimp spoilage (Alvarez 1982) and may 

 be a significant spoilage organism of elasmo- 

 branch flesh. 



ment on flesh did not correlate well in all respects 

 with results of other studies which in some in- 

 stances were limited to one or a few fish or differ- 

 ent species than those considered here. Also, little 

 information was provided in the literature on cul- 

 tural conditions and other variables which could 

 affect development of various bacteria reported. 

 The data here substantiate the occurrence of cer- 

 tain potential spoilage bacteria on skin and in- 

 clude the genus Planococcus which has been im- 

 plicated in shrimp spoilage. The present study also 

 confirms and extends other observations on the 

 occurrence of hemolytic bacteria on shark teeth. 

 In addition, potentially pathogenic enterobacteria 

 were recovered from teeth and intestinal contents 

 of several elasmobranch species. It is hoped that 

 future studies will include larger numbers of addi- 

 tional shark species for a clearer assessment of the 

 role of bacteria in both spoilage and public health 

 aspects of a valuable and underutilized marine 

 resource. 



ACKNOWLEDGMENTS 



The majority of this research was conducted at 

 the Mote Marine Laboratory, Sarasota, Fla., while 

 the author was on sabbatical leave. I am especially 

 indebted to William H. Taft, President, for provid- 

 ing space and facilities. Appreciation is extended 

 also to Carl Luer and Perry Gilbert of the Mote 

 Laboratory for valuable advice and background 

 information. Jack Schneider furnished the shark 

 from the Mystic Marinelife Aquarium. I thank 

 Denise Baird and Shannon Kelly for their time 

 and patience in assisting with laboratory identifi- 

 cation of bacterial isolates. 



LITERATURE CITED 



CONCLUSIONS 



The observations reported here have shown that 

 elasmobranch fish contain a large and diverse 

 bacterial flora. Because there is little information 

 on the microbiology of sharks, skates, and rays, 

 assessing the relative significance of the data is 

 difficult. In many cases, counts of bacteria on the 

 skin were an order of magnitude higher than those 

 noted on osteichthyan fish caught in the same 

 waters. In other samples, counts were two orders of 

 magnitude lower. Considerable variation was seen 

 in individual species of elasmobranchs. Types of 

 bacteria recovered from different areas of fresh 

 fish and during one controlled spoilage experi- 



ALVAREZ, R. J. 



1982. Role of Planococcus citreus in the spoilage of Pen- 

 naeus shrimp. Zentralbl. Bakteriol. Parasitenkd. In- 

 fektionskr. Hyg. Abt. I Orig. C3:503-512. 

 BALDRIDGE, H. D. 



1974. Shark attack. Berkley Publ. Corp., N.Y., 263 p. 

 BUCHANAN, E. G., AND N. E. GIBBONS (editors). 



1974. Bergey's manual of determinative bacteriology. 8th 

 ed. The Williams and Wilkins Co., Baltimore, 1268 p. 

 BUCK, J. D. 



1982. Nonstaining (KOH) method for determination of 

 Gram reactions of marine bacteria. Appl. Environ. Mi- 

 crobiol. 44:992-993. 

 BUCK. J. D., AND R. C. CLEVERDON. 



1960. The spread plate as a method for the enumeration of 

 marine bacteria. Limnol. Oceanogr. 5:78-80. 



Carey, F. G., J. M. Teal, and J. W. kanwisher. 



1981 . The visceral temperatures of mackerel sharks ( Lam- 



380 



