167 



Abstract — There is increasing inter- 

 est in the potential impacts that fish- 

 ing activities have on megafaunal 

 benthic invertebrates occurring in 

 continental shelf and slope ecosys- 

 tems. We examined how the structure, 

 size, and high-density aggregations 

 of invertebrates provided structural 

 relief for fishes in continental shelf 

 and slope ecosystems off southern 

 California. We made 112 dives in 

 a submersible at 32-320 m water 

 depth, surveying a variety of habi- 

 tats from high-relief rock to flat sand 

 and mud. Using quantitative video 

 transect methods, we made 12,360 

 observations of 15 structure-form- 

 ing invertebrate taxa and 521,898 

 individuals. We estimated size and 

 incidence of epizoic animals on 9105 

 sponges, black corals, and gorgonians. 

 Size variation among structure-form- 

 ing invertebrates was significant and 

 909c of the individuals were <0.5 m 

 high. Less than 1% of the observa- 

 tions of organisms actually shelter- 

 ing in or located on invertebrates 

 involved fishes. From the analysis of 

 spatial associations between fishes 

 and large invertebrates, six of 108 

 fish species were found more often 

 adjacent to invertebrate colonies than 

 the number of fish predicted by the 

 fish-density data from transects. This 

 finding indicates that there may be 

 spatial associations that do not neces- 

 sarily include physical contact with 

 the sponges and corals. However, the 

 median distances between these six 

 fish species and the invertebrates were 

 not particularly small (1.0-5.5 m). 

 Thus, it is likely that these fishes and 

 invertebrates are present together in 

 the same habitats but that there is not 

 necessarily a functional relationship 

 between these groups of organisms. 

 Regardless of their associations with 

 fishes, these invertebrates provide 

 structure and diversity for continental 

 shelf ecosystems off southern Califor- 

 nia and certainly deserve the atten- 

 tion of scientists undertaking future 

 conservation efforts. 



Benthic invertebrates that form habitat 

 on deep banks off southern California, 

 with special reference to deep sea coral 



Brian N. Tissot 



Program in Environmental Science and Regional Planning 

 14204 NE Salmon Creek Ave. 

 Washington State University 

 Vancouver, Washinton 98686-9600 

 E-mail address tissot'a Vancouver wsu edu 



Mary M. Yoklavich 



Fisheries Ecology Division 



Southwest Fisheries Science Center 



National Marine Fisheries Service, NOAA 



Santa Cruz Laboratory 



110 Shaffer Road 



Santa Cruz, California 95060 



Milton S. Love 



Marine Science Institute 



University of California 



Santa Barbara, California 93106 



Keri York 



Program in Environmental Science and Regional Planning 

 14204 NE Salmon Creek Ave. 

 Washington State University 

 Vancouver, Washington 98686-9600 



Mark Amend 



Southwest Fisheries Science Center 



National Marine Fisheries Service, NOAA 



Santa Cruz Laboratory 



110 Shaffer Road 



Santa Cruz, California 95060 



Manuscript submitted 8 December 2004 

 to the Scientific Editor's Office. 

 Manuscript approved for publication 

 21 July 2005 by the Scientific Editor. 

 Fish. Bull. 104:167-181 (2006). 



Science and conservation communi- 

 ties are increasingly interested in the 

 potential impacts that fishing activi- 

 ties have on megafaunal benthic inver- 

 tebrates found in continental shelf and 

 slope ecosystems (Dayton et al., 2002; 

 NRC, 2002; Malakoff, 2004; Roberts 

 and Hirshfield, 2004; Rogers, 2004). 

 Megafaunal invertebrates (>5 cm in 

 height) contribute significantly to bio- 

 diversity, play important functional 

 ecological roles, and can be indica- 

 tors of long-term environmental condi- 

 tions (e.g., Riedl, 1971; Palumbi, 1986; 

 Brusca and Brusca, 1990). Moreover, 

 because large invertebrates, such 

 as sponges and corals, enhance the 



diversity and structural component 

 of fish habitat and are vulnerable to 

 impacts by at least some fisheries, 

 they also may signify habitat areas 

 of particular concern (HAPC) and as 

 such would be protected under the 

 Magnuson-Stevens Fishery Conser- 

 vation and Management Act (Freese, 

 2001; Etnoyer and Morgan^). 



' Etnoyer, P., and L. Morgan. 2003. Oc- 

 currences of habitat-forming deep 

 sea corals in the Northeast Pacific 

 Ocean. Technical Report, NOAA Office 

 of Habitat Conservation, 31 p. Marine 

 Biologv Conservation Institute, 15806 

 NE 47'h Ct., Redmond, WA 98052. 



