Aquaculture potential of the basket cockle (Clinocardium nuttallii). Part 2: effects of stocking density and depth on second year grow‐out performance of three size cohorts in intertidal and off‐bottom suspended culture |
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| Authors: | Helen Gurney‐Smith Nadia Plamondon Simon Yuan Christopher M Pearce |
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| Institution: | 1. Centre for Shellfish Research, Vancouver Island University, , Nanaimo, BC, Canada;2. Department of Fisheries and Aquaculture, Vancouver Island University, , Nanaimo, BC, Canada;3. Marine Ecosystems and Aquaculture Division, Pacific Biological Station, Fisheries and Oceans Canada, , Nanaimo, BC, Canada |
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| Abstract: | We investigated the effects of culture mode (intertidal and off‐bottom suspended culture) and initial stocking density (5%, 10%, 35% and 70% bottom cover) on survival, growth and condition indices of three size cohorts (16, 22 and 32 mm initial shell length) of the basket cockle, Clinocardium nuttallii, during a second year of grow‐out. In addition, we evaluated the effects of depth (2, 4 and 6 m) in suspended culture. All size cohorts demonstrated significantly higher growth rates, soft‐tissue biomass and condition indices in the off‐bottom suspended system compared to the intertidal one. In suspended culture, however, C. nuttallii exhibited sub‐optimal survival, shell deformities and heavy fouling. For all size cohorts, stocking density had a significant effect on most growth and condition parameters, except meat yield indices, in both culture modes. An initial maximum stocking density of 10% cover is recommended for all size cohorts. Culture depth did not have a consistent statistically significant effect on any of the growth or condition parameters. Depending on the grow‐out scenario, stocking density and harvestable size chosen, the cumulative harvestable proportion after the second year of grow‐out constituted 15.5–63.1% of the seed planted. Our results could be used to develop and improve culture techniques for C. nuttallii and other cockle species. |
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| Keywords: | aquaculture Clinocardium nuttallii cockle culture mode grow‐out stocking density |
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