Comparative fishing trials for cod and haddock using commercial trawl and longline at two different stock levels
Fishing trials were performed simultaneously using commercial bottom trawl and longline in an investigation that was primarily designed to explore the effects of seismic airgun shooting on catch rates of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Fish density, species and length comp...
| Main Authors: | , , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1996
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.503.5925 http://journal.nafo.int/J19/engas.pdf |
| Summary: | Fishing trials were performed simultaneously using commercial bottom trawl and longline in an investigation that was primarily designed to explore the effects of seismic airgun shooting on catch rates of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Fish density, species and length composition in the experimental area were determined from a combined acoustic and bottom trawl survey. The seismic shooting led to lower fish density and changes in size and species composition, and analyzing catch data obtained before and after shooting made it possible to compare the species and length compositions of trawl and longline catches at two different stock levels. The fishing trials showed that both the species and size compositions obtained by the two gears were significantly different. Relatively more haddock were caught by longline than by trawl, and longline fishing was found to catch less undersized cod and more undersized haddock than trawling. It appeared that the size compositions of the longline catches were affected by the fish density and size composition in the area. The implications of these results for optimal harvest strategy are discussed. Key words: Cod, gear se lect iv i ty, haddock, longl ine, s ize composi t ion, species composition, trawl |
|---|