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Title: The biology of rocky shore fishes and fish leeches
Author: Hussain, N. A.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1979
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1. Regional collections showed the dominant species to be boreal-atlantic in Northumberland and Scotland and mediterranean-atlantic in South West Britain. Blennius pholis, Ciliata mustela and Enophrys bubalis are abundant on all suitable shores. 2. In winter near Swansea all species except Blennius pholi were restricted to low levels, but in summer and autumn Ciliata mustela, Gobius paganellus and others spread higher, following recruitment of young. 3. Enophrys bubalis was studied particularly. Age was determined by length frequency analysis and by light microscopy and SEM of otoliths. Growth is rapid during the first two years, and then less so. It is confined to spring and summer. Females grow faster and may live for five years, but males only live for three years. 4. The condition factor does not vary significantly with region, but it varies seasonally, is higher in females and increases with length of fish. 5. The gonosomatic index is higher in females and larger fish, but decreases during April and May, presumably with spawning. Females outnumber males but there are more males amongst young fish. Urogenital papillae of males are elongated, especially when spawning (suggesting internal fertilization), but males nevertheless guard eggs. 6. The gut contents included 69 species. Adults eat mostly teleosts, decapods and polychaetes, juveniles mainly Amphipoda and Isopoda. 7. The leech Oceanobdella blennii was locally abundant on mature Blennius pholis from February to May, but scarce in South Wales and absent from Devon. In Scotland, it parasitised Pholis gunnellus. Oceanobdella microstoma was found on Enophrys bubalis and Myoxocephalus scorpius during February to April, sparsely but evenly distributed around Britain. Sanguinothus pinnarum occurred on Enophrys bubalis from February to July in Anglesey and Northumberland. These leeches are low temperature stenotherms and notably host specific. 8. Another leech, trawled on Pleuronectes, resembles Platybdella anarrhichae in its male genital system, gut and coelom, but differs in skin structure.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available