Keeping Arctic fisheries as happy as a clam: assessing the life history and density of truncated soft-shell clams (Mya truncata) of southern Baffin Island, Nunavut, to promote sustainable fishery development

Wood, Jessica Marie (2020) Keeping Arctic fisheries as happy as a clam: assessing the life history and density of truncated soft-shell clams (Mya truncata) of southern Baffin Island, Nunavut, to promote sustainable fishery development. Masters thesis, Memorial University of Newfoundland.

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Abstract

Fishery development is a priority for Arctic governments, Indigenous organizations, and communities to promote Arctic economic development and food security. The recreational truncated soft-shell clam (Mya truncata) fishery of southern Baffin Island, Nunavut, is expected to undergo increased fishing pressure with northern population expansion and potential commercial development in Frobisher Bay and on the north shore of the Hudson Strait. Understanding aspects of the life history and population density of M. truncata of southern Baffin Island is key to sustainable fishery development. I first found the shell length at 50% sexual maturity to be 31 and 32mm in male and female M. truncata, respectively. Based on the stage of gonadal development observed in sexually mature clams collected from inner Frobisher Bay in late August 2018 and Hudson Strait in early September 2018, I suspect a late-summer or fall spawning event may have taken place in 2018. I identified strong length-bias in calculated condition indices for these populations, and so I used dry-body weight to shell length relationships to gauge population condition over small and large spatial scales. I then implemented a drop-camera set-up using the frame of a snow crab trap, a GoPro, lasers and a weight strung on a monofilament line for scale to assess M. truncata density in the intertidal zone. By comparing drop-camera density estimates with those obtained by manual excavations, I determined that drop-camera deployments within the intertidal zone estimate significantly less clams than excavation estimates across all sites. This difference was attributed to smaller clam siphons not being visible in video, the retraction of siphons at low tide, and fine sediment displacement with tidal flow covering siphons. This research is expected to help with community-based resource harvest plans and conservation measures and to inform policy at regional, territorial, and national levels.

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