Growth rate of the Iceland scallop Chlamys islandica in Gilbert Bay, Labrador, a marine protected area

Liu, Shanshan (2009) Growth rate of the Iceland scallop Chlamys islandica in Gilbert Bay, Labrador, a marine protected area. Masters thesis, Memorial University of Newfoundland.

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Abstract

The sustainability of the Iceland scallop fishery is one of the conservation issues associated with the Gilbert Bay Marine Protected Area in southeastern Labrador. The average size of Iceland scallop in Gilbert Bay is significantly smaller than the average scallop size in the nearby Strait of Belle Isle. Local fishers have suggested this could be due to a slower growth rate of scallops in the MPA. -- To estimate the growth rate of scallops in Gilbert Bay, three methods of determining the age of scallops were used: counting external shell growth rings, counting shell hinge ligament growth zones, and counting internal shell layer growth increments. No significant difference was found between the ligament and internal shell methods of aging, but both methods were significantly different from the external shell growth ring method. Counting hinge ligament growth zones was recommended as the most accurate and most convenient method. The growth parameters of Iceland scallop in Gilbert Bay were found by fitting the von Bertalanffy equation to the shell height-at-age data. Based on counting hinge ligament growth zones, the von Bertalanffy model found asymptotic shell height (SHoo) of scallops in Gilbert Bay was 117 mm with a growth parameter K of 0.07 year⁻¹. Scallop growth in Gilbert Bay is not significantly different from scallop growth in the Strait of Belle Isle and not significantly different from scallop growth in the Nuuk area of West Greenland. -- No significant difference was found in variation of scallop growth throughout Gilbert Bay. Scallops in Gilbert Bay are currently smaller than in the Strait of Belle Isle, likely due to factors other than growth rate, such as variance in recruitment, natural mortality or fishing mortality. Refined harvesting regulations could ensure the sustainability of Iceland scallop populations in Gilbert Bay.

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