Analyses/Maps

Fish

HSI Integration - Flatfish

About these maps:
The maps displayed here provide one approach to assess habitat suitability based on HSI results for multiple species. HSI model results were averaged to assess the potential distribution of suitable habitats for 5 species of adult (left) and subadult (right) flatfish. Predicted HSI values range in scale from 10 (highest) to 0 (unsuitable). HSI results were grouped into five classes: highest suitability (10-8), moderate (7-5), low (4-2), lowest (1), and unsuitable (0).

Data sources:
Adult and subadult HSI maps for Dover sole, English sole, Pacific sanddab, Petrale sole, and Rex sole (CD-Rom).

Methods:
See HSI Methods for HSI map development. Maps of mean HSI were developed by overlaying each individual HSI map and calculating the arithmetic mean across grid cells.

Results and Discussion:
Individual maps of model results for the five species of flatfish were combined to provide an average HSI value for all species combined. Overall, potential suitability for the adult flatfish assemblage was not predicted to be highly suitable within the study area. Moderate suitability was predicted for most of the shelf area between depths of 50-300 m. Conversely, suitability was high for subadults over shallow (50-110 m) mud and sand substrates and moderate to depths of approximately 300 m. Although these species share similar substrate preferences, depth preference varies for each (especially for adults) and careful consideration should be taken to classify these five species into an assemblage. Based on the depth SI values developed (see life history spreadsheet) Dover sole and Rex sole could be grouped together, and the remaining three could form a separate assemblage.