Effects of selected mixed-algal diets on growth and survival of early postset juveniles of the Pacific geoduck clam, Panopea generosa (Gould, 1850)

Authors

  • Y. Ren,

    1. Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, China
    2. Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada
    Current affiliation:
    1. Qingdao Agricultural University, Chengyang, Qingdao, China
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  • W. Liu,

    1. Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada
    2. Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
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  • C.M. Pearce,

    Corresponding author
    1. Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, British Columbia, Canada
    • Correspondence: C.M. Pearce, Fisheries and Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia V9T 6N7, Canada. E-mail: Chris.Pearce@dfo-mpo.gc.ca

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  • I. Forster,

    1. Fisheries and Oceans Canada, West Vancouver Laboratories, Vancouver, British Columbia, Canada
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  • R.S. McKinley

    1. Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
    2. Centre for Aquaculture and Environmental Research, The University of British Columbia/Fisheries and Oceans Canada, Vancouver, British Columbia, Canada
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Abstract

Four microalgal species [Dunaliella tertiolecta, Phaeodactylum tricornutum, Tetraselmis suecica, Thalassiosira pseudonana], previously identified as poor single-algal diets for juvenile geoduck clams, Panopea generosa, were selected to mix with two comparatively better food-value microalgae [Isochrysis sp. (TISO), Chaetoceros muelleri (CM)] to estimate synergistic or non-additive effects of mixed microalgae on the growth/survival of young juveniles of P. generosa. In addition, the effects of different TISO/CM proportions [75/25, 50/50, 25/75; ash-free dry weight (AFDW) basis] on growth/survival were assessed. Shell length, wet weight, dry weight, AFDW and organic matter content were significantly increased when using mixed TISO diets compared with TISO alone. In contrast, there were no significant differences with these variables when comparing mixed CM diets with CM alone. Ultimately, the best diet in terms of length and weight enhancement was a previously identified optimal one of TISO/CM (50/50). Survival on day 23 (60.7–79.3%) was not significantly different among any of the 11 diets tested. There were no significant differences in shell length, wet weight, dry weight, AFDW and organic matter content among the three TISO/CM ratios tested, but these diets gave superior results to TISO and CM fed alone. Survival (60.7–74.7%) on day 23 in the three TISO/CM ratios tested did not vary significantly.

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