Food and feeding of the hooded seal (Cystophora cristata) in Newfoundland
Knowledge of diet is fundamental to studies of seal ecology and especially to any understanding of their role as predators in the northwest Atlantic marine ecosystem. Hooded seals (Cyostophora cristata ) are one of the largest of the northern phocids and are abundant in the north Atlantic and Arctic...
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| Format: | Thesis |
| Language: | English |
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Memorial University of Newfoundland
1992
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| Online Access: | https://research.library.mun.ca/4222/ https://research.library.mun.ca/4222/1/Ross_Sue-Anne.pdf https://research.library.mun.ca/4222/3/Ross_Sue-Anne.pdf |
| Summary: | Knowledge of diet is fundamental to studies of seal ecology and especially to any understanding of their role as predators in the northwest Atlantic marine ecosystem. Hooded seals (Cyostophora cristata ) are one of the largest of the northern phocids and are abundant in the north Atlantic and Arctic seas, but very little quantitative data is available on their feeding behaviour and dietary preferences. The main objective of this study was to determine the diet of hooded seals in Newfoundland waters. -- Otoliths of six common prey species, determined from a previous study on diet of hooded seals, were used to determine fish length / weight - otolith length / height regressions. For all species except Greenland halibut, the strongest correlations between otolith size and fish length / weight were established using maximum otolith length. For Greenland halibut, maximum otolith height gave a better correlation with fish length and weight. Least squares linear equations were used to derive fish length for Arctic cod, Atlantic herring and capelin, while second order polynomial models were used for Greenland halibut, redfish spp., and Atlantic cod. Fish weight estimates were derived using power (log - log) models for all six fish species. -- Stomach contents of 67 hooded seals collected from inshore and offshore waters off Newfoundland were examined to determine the types of prey eaten by hooded seals. The majority of stomachs (73%) came from the nearshore region along the northeast coast of Newfoundland and were taken in April. Over half of the samples collected were female (64.2%). -- Fourteen prey groups were identified in stomachs (10 fish, 4 invertebrate). The relative importance of prey, expressed as the percent total wet weight of prey recovered, indicated that Greenland halibut (Reinhardtius hippoglossoides) was the most important species, followed in order of importance by redfish (Sebastes spp.), Arctic cod (Boreogadus saida), Atlantic herring (Clupea harengus ), squid (Gonatus spp.), Atlantic cod (Gadus ... |
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