CROSS: BIOLOGY OF SCYLIORHINID SHARKS 



dominated the diet of A. brunnetis (36% of total IRI) 

 while natantian decapods dominated the diet of P. 

 xaniurus (40% of total IRI). This may be a result 

 of habitat differences between the catsharks rather 

 than prey selection. The epicaridean isopods in the 

 stomach contents are crustacean parasites, and 

 were probably ingested with their hosts. 



A very high percentage of A. brunneus and P. 

 xaniurus stomachs was empty. This may not be 

 representative of their respective populations. 

 Sharks caught by baited hooks have a higher pro- 

 portion of empty stomachs, and lower stomach 

 content weight, than sharks caught by gill net 

 (Medved et al. 1985). 



Most of the prey consumed by A. brunneus and 

 P. xaniurus are pelagic. Demersal adult P. xaniurus 

 eat mostly crustaceans (including pelagic pasiphaeid 

 and sergestid shrimps), fishes (primarily mycto- 

 phids), and cephalopods. Mesopelagic juveniles eat 

 more and smaller pelagic pasiphaeid, euphausiid, 

 and sergestid shrimps and cephalopods, and fewer 

 fishes (Cailliet fn. 4). Similar pelagic prey also 

 dominate the diets of Galeus melastomus and 

 Apristurus spp., common outer shelf-upper slope 

 scyliorhinid sharks of the northeastern Atlantic 

 Ocean (Orsi and Wurtz 1977; Mattson 1981; Mauch- 

 line and Gordon 1983). Ontogenetic changes in diet 

 were reported for Scyliorhinus canicula: the impor- 

 tance of crustaceans declines and the importance of 

 teleosts increases with increasing fish size (Capape 

 1974). 



Deep-sea benthic fishes can obtain pelagic prey by 

 1) feeding on prey whose vertical distribution ex- 

 tends close to the bottom [P. xaniurus were ob- 

 served eating moribund myctophids in the bottom 

 of the Santa Barbara Basin (Springer 1979)]; 2) 

 migrating into the water column to feed [A. brun- 

 neus and P. xaniurus are captured in midwater 

 (Jones and Geen 1967; Lee 1969; UCSB fn. 3)]; 

 3) feeding on carcasses that sink to the bottom (mud 

 and terrestrial plant debris were found in several 

 catshark stomachs during the present study, and 

 both species took dead bait); or 4) feeding in the net 

 (not a factor in this study) (Pearcy and Ambler 1974; 

 Pearcy 1976; Sedberry and Musick 1978). 



ACKNOWLEDGMENTS 



This study was supported in part by a contract 

 from the County Sanitation Districts of Orange 

 County. Special thanks are extended to the dory 

 fishermen of Newport Beach for taking me on their 

 boats. H. Stubbs, M. Moore, T. Pesitch, and the 



crews of the RV Westwind and RV Vantuna made 

 the trawl collections possible. D. Tsukada and J. 

 Laughlin diligently identified the prey organisms. 

 G. Cailliet, P. Klimley, J. Seigel, and S. Springer 

 provided helpful comments on earlier versions of the 

 manuscript. 



LITERATURE CITED 



CAFAPfi, C. 



1974. Contribution a la biologic des Scyliorhinidae des cotes 

 tunisiennes. ll-Scyliorhimis canicula Linne, 1758: Regime 

 alimentaire. Ann. Inst. Michel Pacha 7:13-29. 



1977. Contribution a la biologic des Scyliorhinidae des cotes 

 tunisiennes. l-Scyliorhinus canicula (Linne, 1758): Repar- 

 tition geographique et bathymetrique, sexualite, reproduc- 

 tion, fecondite. Buil. Off. natn. Pech. Tunisie 1:83-101. 

 Clarke, M. R. B. 



1980. The reduced major axis of a bivariate sample. Bio- 

 metrika 67:441-446. 



COMPAGNO, L. J. V. 



1984. In FAO species catalogue. Sharks of the world. An 

 annotated and illustrated catalogue of shark species known 

 to date. Part 2. Carcharhinilbrmes. Vol. 4, Pt. 2, p. 251- 

 655. FAO Fish. Biol. Synop., No. 125. 

 Cox, K. W. 



1963. Egg-cases of some elasmobranchs and a cyclostome 

 from California waters. Calif. Fish Game 49:271-289. 

 Cross, J. N. 



1987. Demersal fishes of the upper continental slope off 

 southern California. Calif. Coop. Oceanic Fish. Invest. Rep. 

 28:155-167. 

 Day, D. S., and W. G. Pearcy. 



1968. Species associations of benthic fishes on the continen- 

 tal shelf and slope off Oregon. J. Fish. Res. Board Can. 

 25:2665-2675. 



DeLacy, a. C, and W. M. Chapman. 



1935. Notes on some elasmobranchs of Puget Sound, with 

 descriptions of their egg cases. Copeia 1935:63-67. 

 Ford, E. 



1921. A contribution to our knowledge of the life-histories 

 of the dogfishes landed at Plymouth. J. Mar. Biol. Assoc. 

 U.K. 12:468-505. 

 Haedrich, R. L., G. T. Rowe, and P. T. Pollonl 



1975. Zonation and faunal composition of epibenthic popula- 

 tions on the continental slope south of New England. J. 

 Mar. Res. 33:191-212. 



Jones, B. C, and G. H. Geen. 



1977. Observations on the brown cat shark. ApiHsturus brun- 

 neus (Gilbert), in British Columbia coastal waters. Syesis 

 10:169-170. 



Lee. R. S. 



1969. The filetail catshark, Parmaturus xaniurus, in mid- 

 water in the Santa Barbara Basin off California. Calif. Fish 

 Game 55:88-90. 



Mattson, S. 



1981. The food of Galeus melastomus, Gadiculus argenteus 

 thori, Trisopterus esmarkii, Rhinonemus cimbrius, and 

 Glyptocephalus cynoglossu^ (Pisces) caught during the day 

 with shrimp trawl in a west-Norwegian fjord. Sarsia 66: 

 109-127. 



Mauchline, J., and J. D. M. Gordon. 



1983. Diets of the sharks and chimaeroids of the Rockwall 



701 



