Anderson and Yoklavich: Habitat association of deepwater demersal fishes off central California 



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Figure 1 



Seafloor map of the continental shelf in southern Monterey Bay, central California, depicting the 

 three acoustically derived broad-scale strata and Delta submersible sampling locations (dive num- 

 bers 3120-3141). Hard substratum (i.e., complex outcrops) is depicted as dark gray areas. Mixed 

 substratum (areas of hard mixed with soft) is depicted as medium gray areas. Soft substratum 

 (i.e., areas of contiguous soft sediments) is depicted as light gray areas. White areas were not 

 surveyed; box = 10x12 km study area. Bottom insert is an example of the observed intermedi- 

 ate-scale substratum types recorded within the three transects of dive 3121 (depicted by the 

 three rectangles Tl=transect 1, T2 = transect 2, and T3=transect 3) in relation to the seafloor 

 map of that area. Transects sampled in hard substratum (Tl and T2) were heterogeneous and 

 were composed of mixed patches dominated by rock (dark gray), boulders (diagonal hatching) 

 and cobbles (light gray checks). In contrast, transects run within soft substratum (T3) were more 

 homogeneous, composed of either sand (white) or mud (light gray). 



derstanding these associations, however, has received 

 much less attention (Langton et al., 1995). 



In this study, we examined the relationship between 

 deepwater demersal fishes and benthic habitat vari- 

 ables at three spatial scales in an area encompassing 

 a proposed marine protected area (MPA) in southern 

 Monterey Bay, California. At the broad spatial scale 

 of km's, habitat strata were identified from acoustic 

 seafloor maps. Within these strata we conducted sub- 

 mersible transects and recorded both benthic habitat 

 variables — such as substratum type, depth, relief, and 

 habitat patchiness — and fish abundance and size. At the 

 intermediate scale of 10-100's of meters, within-tran- 

 sect habitat measures, in combination with fish counts, 

 provided measures of habitat patchiness and fish use of 

 these patches. Finally, we assessed fine-scale or micro- 



habitat (<1 m) fish-habitat associations by recording the 

 habitat type located directly beneath each fish. These 

 multiple spatial scales of habitat association were in- 

 tegrated to examine multiscale habitat and landscape 

 requirements of these species. 



Material and methods 



Survey of fish habitat 



To quantitatively sample demersal fishes and benthic 

 habitats on the continental shelf in southern Monterey 

 Bay (36°E, 121°S) (Fig. 1), in situ counts and habitat 

 characterizations were made from the two-person Delta 

 submersible. The submersible survey was conducted 



