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Title: Reproductive ecology, population genetics and population dynamics of selected Decapod crustaceans
Author: Klaoudatos, D.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2003
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The reproductive ecology of three species of Decapod crabs, the shore crab (Carcinus maenas), the velvet crab (Necora puber) and the edible crab (Cancer pagurus), were studied in Swansea Bay and South Gower. Spawning occurs over winter and spring (shore crab), winter (edible crab), and summer (velvet crab). Berried females occur in spring and summer (shore crab), winter spring and summer (edible crab), summer and autumn (velvet crab). Eggs hatch in spring and summer (shore crab, edible crab), summer and winter (velvet crab). Copulation occurs in summer and autumn (shore crab), summer, autumn and winter (edible crab, velvet crab). Shore crabs from Swansea Queen’s Dock have a different reproductive cycle compared to the shore crabs from Tawe Barrage Impoundment and Mumbles Pier. More than one spawning periods or an extended spawning period was indicated for the shore crabs in the Docks. The genetic makeup of the shore crab populations present in Swansea Queen’s Dock and Mumbles Pier was compared using SSCP and cloning analysis of the 16S rRNA. Four different haplotypes were identified all of which were present in the Docks and one in the Pier, with low level of genetic divergence, and close relationship of the identified haplotypes with published shore crab haplotypes. AMOVA showed no significant difference between the study populations and published shore crab haplotypes. However, all identified haplotypes were different from published shore crab haplotypes, indicating a degree of reproductive isolation of the Swansea shore crab populations. Analysis of the permit return data for 1980-2002 of the edible and velvet crab fishery for the South Wales Sea Fisheries Committee District indicated that a combination of factors including overfishing, environmental conditions, and the “Sea Empress” oil spill in 1996 have contributed to a decline in landings that continues to date with limited signs of recovery.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available