Recently, questions have been raised as to the appropriateness of stock boundaries in the Atlantic horse mackerel (<i>Trachurus trachurus</i>) and the herring (<i>Clupea harengus)</i> in European waters. To this end, 1919 horse mackerel were examined for parasitic infections from samples taken at nineteen sites around Europe. Forty-five species of parasites were recorded, eleven of which are new host records, and one may be a new species. A number of these are suitable for use as biological tags. Results showed a significant degree of separation between fish from the North Sea and Western stocks, based on the relative abundance of the nematodes <i>Aniaskis </i>spp. and <i>Hysterothylacium</i> sp. The endoparasitic fauna of 4033 herring at various life stages from sites to the west of the British Isles, the North Sea, Baltic Sea and northern Norway were examined to obtain information on stock identity, mixing and recruitment patterns in these areas. Results revealed that substantial stock mixing takes place to the west of the British Isles, with fish from a wide area being found together in non-spawning aggregations off the Hebrides. This area is also home at different times of year to two different spawning populations of fish which recruit from nursery grounds in the eastern North Sea and from the west of Scotland. Investigations were made of the usefulness of the ribosomal small sub-unit cytochrome oxidase (I) gene of the parasitic nematode worm, <i>Anisakis simplex s.s., </i>as a tag of host population biology. Results revealed the COI gene to be highly variable, with around 50% of worms sequenced having unique haplotypes. There were no population structures evident from analysis of genetic distances.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:446199 |
| Date | January 2008 |
| Creators | Campbell, Neil |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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