Linkages Between Habitat and Distribution and Abundance of Fish Species

Significance

On land, we know species occurrences correlate strongly with habitat type. The same is true in the ocean, only it is orders of magnitude more difficult to map the ocean floor, current regimes, water chemistry, and light profiles that define oceanic habitats. Finding robust proxies for the distribution of benthic habitats would be invaluable to efforts focused on preserving and protecting marine biodiversity.

Project Summary:

This study explored and assessed the basic correlation between fish species or species assemblages and seafloor habitat.

Location:

Stellwagen Bank, 1999

  • Peter Auster, University of Connecticut,
  • Kevin Joy, University of Connecticut
  • Page Valentine, U.S. Geological Survey
  • Funded by: National Oceanic and Atmospheric Administration’s National Undersea Research Program, Stellwagen Bank National Marine Sanctuary, U.S. Geological Survey
Project Detail:
Abstract from paper:

Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the difficulty of making observations of seafloor habitats. Fish distribution data, however, are more readily available because of the economic importance of the fisheries and subsequent regularity of resource surveys and keeping of catch statistics. Fish distribution data (species or communities) have already been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study in the Stellwagen Bank National Marine Sanctuary we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance data from multibeam sonar surveys.

We found that fish communities were correlated with multibeam sonar reflectance values, but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of fish communities within an area could indicate a greater range of habitat types.

Single species distributions showed relationships between abundance and reflectance values. Trawl samples with low abundances for each species had wide variations in reflectance values while those with high abundances generally had narrower ranges indicating specific habitat associations. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

Publications:
Auster, Peter J., Kevin Joy, Page C. Valentine. 2001. Fish species and community distributions as proxies for seafloor habitat distributions: the Stellwagen Bank National Marine Sanctuary example (Northwest Atlantic, Gulf of Maine). Environmental Biology of Fishes 60:331-346.