168 



Abstract — Fish-habitat associations 

 were examined at three spatial scales 

 in Monterey Bay, California, to deter- 

 mine how benthic habitats and land- 

 scape configuration have structured 

 deepwater demersal fish assemblages. 

 Fish counts and habitat variables were 

 quantified by using observer and video 

 data collected from a submersible. 

 Fish responded to benthic habitats 

 at scales ranging from em's to km's. 

 At broad-scales (km's), habitat strata 

 classified from acoustic maps were a 

 strong predictor of fish assemblage 

 composition. At intermediate-scales 

 (m's-100 m's), fish species were asso- 

 ciated with specific substratum patch 

 types. At fine-scales (<1 m), micro- 

 habitat associations revealed differing 

 degrees of microhabitat specificity, 

 and for some species revealed niche 

 separation within patches. The use of 

 habitat characteristics in ecosystem- 

 based management, particularly as a 

 surrogate for species distributions, 

 will depend on resolving fish-habitat 

 associations and habitat complexity 

 over multiple scales. 



Multiscale habitat associations 

 of deepwater demersal fishes 

 off central California 



Tara J. Anderson (contact author) 

 Mary M. Yoklavich 



Email address lorT. J. Anderson: t.anderson@alms.gov.au 



Fisheries Ecology Division 

 Southwest Fisheries Science Center 

 National Marine Fisheries Service 

 110 Shaffer Road, 

 Santa Cruz, California 95060 

 Present address (for T J Anderson); 



Australian Institute of Marine Science 

 PMB 3 Townsville MC 

 Queensland 4810, Australia 



Manuscript submitted: 16 June 2006 

 to the Scientific Editor. 



Manuscript approved for publication 

 17 August 2006 by the Scientific Editor. 



Fish. Bull. 105:168-179 (2007). 



Measuring fish-habitat associations on 

 a number of spatial scales is essential 

 in determining the relative importance 

 of habitat types and landscape configu- 

 ration in structuring fish assemblages 

 and populations. Many benthic habi- 

 tat characteristics (e.g., substratum 

 type, depth, relief) are important in 

 explaining the local distribution and 

 abundance patterns of demersal fishes 

 (e.g., Jones and Syms 1998; Stephens 

 et al., 2006). An organism's use of 

 habitat may also change as a function 

 of scale (Wiens, 1989). For example, 

 fishes may make a considerable range 

 of choices about their occupancy of 

 specific habitats and may sample their 

 environment at a range of spatial and 

 temporal scales (Ault and Johnson, 

 1998; Syms and Jones, 1999). Habitat 

 types (abiotic and biotic), however, are 

 found within a large spatial domain 

 (landscape) in which the configuration 

 and connectivity between neighbor- 

 ing habitat areas may contribute to 

 population structure (Forman, 1995). 

 For example, landscape configura- 

 tion and the degree of habitat patchi- 

 ness may modify the distribution and 

 movement of an organism, and the 

 interactions among species (Addicott 

 et al., 1987). 



On the U. S. West Coast, demersal 

 fishes, particularly rockfishes iSe- 

 hasfes) are a dominant feature of the 

 benthic ecosystem (Love and Yoklav- 

 ich, 2006) and are important for both 

 commercial and recreational fisheries 



(Love, 2006). At broad spatial scales, 

 traditional trawl surveys have docu- 

 mented a range of biogeographical 

 and depth patterns for harvested de- 

 mersal species (Gunderson and Sam- 

 ple, 1980; Weinberg, 1994; Williams 

 and Ralston, 2002). Less research has 

 been done on the role that benthic 

 habitat variables, such as substra- 

 tum type and relief, play in explain- 

 ing the distribution and abundance of 

 either commercial or noncommercial 

 species. Strong relationships between 

 demersal fish species and a range of 

 habitat characteristics, particularly 

 substratum type and abundance of 

 giant kelp, have been identified in 

 shallow (<30 m) coastal waters (Ste- 

 phens et al., 2006). However, many 

 demersal species in this system, par- 

 ticularly rockfish species, are found 

 over extensive depth ranges beyond 

 those that can safely be investigated 

 with SCUBA (Love et al., 2002). The 

 use of submersibles and remotely op- 

 erated vehicles (ROVs), with sampling 

 protocols similar to those of nearshore 

 surveys (Stein et al., 1992; Adams 

 et al., 1995; Yoklavich et al., 2000), 

 provides the capabilities to make 

 quantitative in situ observations of 

 fish-habitat associations in deepwater 

 (>30 m). Studies in which these tools 

 are employed are also beginning to 

 demonstrate characteristic habitat as- 

 sociations for deepwater demersal fish 

 species (Love and Yoklavich, 2006). 

 The importance of spatial scale in un- 



