Environmental Factors Influencing the Distribution of Juvenile Groundfish in Nearshore Habitats of Southwest Nova Scotia
Eight nearshore (< 20 m) marine habitats were surveyed to estimate the relative abundance of juvenile groundfish and to assess the environmental variables influencing their distribution. Surveys were conducted as part of a depth-stratified, random sampling design; at each site a small otter t...
| Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1989
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f89-164 http://www.nrcresearchpress.com/doi/pdf/10.1139/f89-164 |
| Summary: | Eight nearshore (< 20 m) marine habitats were surveyed to estimate the relative abundance of juvenile groundfish and to assess the environmental variables influencing their distribution. Surveys were conducted as part of a depth-stratified, random sampling design; at each site a small otter trawl was towed for 15 min at eight stations in each of three depth strata. A suite of 13 environmental variables were measured in association with each tow. A total of 1908 fish from 13 different species were caught at 191 completed trawl stations. Standardized centered principal components analysis, orthogonally rotated factor analysis, and detrended correspondence analysis (DCA) were used to delineate aggregations in the abundance data. DCA coupled with stepwise multiple regression best resolved the species' distributions and dominant gradients in the environment. The first two DCA axes reflected estuarine to coastal gradients (68% of the variance) and significant environmental variables were plotted as vectors in the ordination diagram. An estuarine assemblage of species, characterized by winter flounder (Pseudopleuronectes americanus) and white hake (Urophycis tenuis), was associated with waters that were warmer, less saline, more turbid, and overlying a finer grained substrate, than a coastal assemblage of species which included cod (Gadus morhua) and rock gunnel (Pholis gunnellus). The biologically significant gradients corresponded to those which dominated variation in the physical environment. |
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