The Ecology and Conservation of European Smelt (Osmerus eperlanus L.) from Waterford Estuary, in Southeastern Ireland
| Autor: | D. Doherty, T. K. McCarthy |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Biology & Environment: Proceedings of the Royal Irish Academy. 104:125-130 |
| ISSN: | 2009-003X 0791-7945 |
| DOI: | 10.3318/bioe.2004.104.2.125 |
| Popis: | The smelt (Osmerus eperlanus L.) is a little-known indigenous fish species in Ireland. All known Irish populations are anadromous. A total of 173 smelt were captured using a variety of fishing methods in Waterford Estuary over the period June 1997 � /June 1998. Analyses of the stomach contents revealed that they fed almost exclusively upon the marine mysid Praunus neglectus and other macroinvertebrates such as Hyperia galba and Crangon allmani. Piscivorous feeding, including cannibalism, was also evident, and three fish species were recorded in the smelt stomach contents (Merlangus merlangus, Sprattus sprattus and Osmerus eperlanus). Seasonal variation in feeding intensity was also noted. Six metazoan parasite species were recorded from the Waterford Estuary smelt. These included two digeneans (Diplostomum spathaceum and D. gasterostei), one cestode (Proteocephalus longicollis), two nematodes (Hysterthylacium aduncum and Anisakinae sp.) and one ectoparasitic crustacean species (Caligus eperlanus). Parasite prevalences and mean intensities of infection were recorded. The smelt examined ranged from 1� /to 5� /years, with the majority belonging to the 2� /and 3� /cohorts. They varied in size (125 � /260mm fork length) and in weight (15 � /129g). Their growth rates were broadly similar to those of smelt populations elsewhere in Europe. Maturation of gonads and increasing egg diameter in ovaries of female smelt in the Waterford Estuary were noted prior to a spring spawning period. No clear correlations were found for either mean egg diameter or fecundity when parental body size or age were taken into account. However, this may be due to the relatively small sample size. |
| Databáze: | OpenAIRE |
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