Densities, distributions, and individual size of Orange-Footed Sea Cucumber (Cucumaria frondosa) on the Scotian Shelf
LE3 .A278 2020
Master of Science
Traditional sea cucumber fisheries have collapsed due to over-fishing, however demand for sea cucumber products has continued to rise. Fisheries for the Orange-Footed Sea Cucumber (Cucumaria frondosa) have developed in Eastern Canada to fill this void. A review of the current state of knowledge for C. frondosa and an outline and history of all Eastern Canadian C. frondosa fisheries highlights the lack of fisheries-related data. Drop-camera surveying was tested for practicality to supplement fisheries-dependent data for use in management decisions. Techniques proved useful in identifying new areas of high C. frondosa densities and highlighted the strong connection between hard substrate and high densities. Species of potential bycatch were also identified. Camera survey techniques enabled the collection of ecological data with minimal impacts on habitat and animal behaviour. Drop-camera surveying is recommended for continued use as a fisheries-independent tool to monitor the effects of fishing pressure. Current fisheries-dependent data collection involves the measurement of lengths and weights of C. frondosa for a portion of each catch. Measurements of size can be used to identify trends and monitor effects of fishing pressure over time. Several measurements of size of C. frondosa were evaluated for consistency and accuracy over various time intervals out of water. Indices that incorporate length and width were more highly correlated with wet weight than length or width alone. Water expulsion occurred within the first 10 minutes after removal from the tank, suggesting that measurements after 10 minutes out of water provide more consistency. Standard practices for the collection of fisheries-dependent and fisheries-independent data are vital and continued monitoring of densities, distributions, and individual size will provide data for informed decisions making, leading the maritime C. frondosa industry toward long-tern sustainability.
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