The return of cod transplanted from a spawning ground in southern Newfoundland
To investigate the navigation mechanisms used by Atlantic cod ( Gadus morhua ) to locate spawning grounds we conducted a biotelemetric study in which 23 large (74–98 cm) spawners were displaced in small groups up to 35 km from a coastal Newfoundland spawning ground at Bar Haven, Placentia Bay. Overa...
| Published in: | ICES Journal of Marine Science |
|---|---|
| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
2002
|
| Subjects: | |
| Online Access: | http://icesjms.oxfordjournals.org/cgi/content/short/59/6/1285 https://doi.org/10.1006/jmsc.2002.1313 |
| Summary: | To investigate the navigation mechanisms used by Atlantic cod ( Gadus morhua ) to locate spawning grounds we conducted a biotelemetric study in which 23 large (74–98 cm) spawners were displaced in small groups up to 35 km from a coastal Newfoundland spawning ground at Bar Haven, Placentia Bay. Overall, approximately 60% of the transplanted fish returned to the grounds, most within a few days. The data derived from this exercise allow the development of hypotheses regarding the navigatory mechanisms used by cod during movements on a small scale spatially. The return success was negatively related to distance of the release sites from the spawning ground (p<0.05) but was higher when fish were released along a known migratory pathway, or when released upcurrent of the spawning site. There was no support for the hypotheses that cod conducted contra-natant spawning migrations or tracked water-borne chemical-olfactory signals respectively. Transplanted groups did not stay together but a group transplanted near a large cod aggregation stayed there for some time, although 50% eventually returned to Bar Haven. Finally, our data suggest that cod moved towards an omnidirectional “attractor”, such as a characteristic sound or geophysical signature, that dissipates with distance perhaps in combination with spatial memory of bathymetry or current structures and the presence of maturing conspecifics. |
|---|