Interactive effects of initial size, stocking density, and type of predator deterrent netting on survival and growth of cultured juveniles of the soft-shell clam, Mya arenaria L., in eastern Maine
Interactive effects of initial size, stocking density, and type of predator deterrent netting on survival and growth of cultured juveniles of the soft-shell clam, Mya arenaria L., in eastern Maine
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DOI：
10.1016/s0044-8486(01)00900-0
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发表时间：
2002-05-31
期刊：
影响因子：
4.5
通讯作者：
Kraus, MG
中科院分区：
文献类型：
--
作者：
Beal, BF;Kraus, MG
最近，美国缅因州软壳蛤（Mya arenaria L.）的商业收成下降，促使州和地方官员考虑使用孵化场饲养的种子来增加野生种群。本文于1990 ~ 1991年在美国缅因州东部的软底潮间带进行了两次野外试验，研究了捕食、种内竞争和初始种植规模对Mya养殖个体生存和生长的影响。试验1（1990年6月23日至1991年6月13日）测试了两种种植规模(小=8.5 mm壳长（SL）；大=11.8 mm SL)和防护网对蛤的命运和生长的影响。将每种大小的动物分别放入由木盒划定的60个1-m(2)区域内的单独实验单元中。为了阻止捕食者，50个盒子上覆盖了一种特定类型的塑料网，孔径大小（4.2、6.4和12.8毫米）和刚性程度（柔性与挤压）不同，而10个盒子作为对照组（没有网）。小蛤的生长速度比大蛤快，但在研究结束时，两者都增加了大约18毫米的新壳。生长不受渔网大小和硬度的影响，但一年后，有保护的蛤蜊比无保护的蛤蜊活得多13%（84%比71%）。存活率与网型无关。由于网的存在，野生口贝的数量增加了近3倍(
Recent declines in commercial harvests of soft-shell clams, Mya arenaria L., in Maine, USA, have prompted state and local officials to consider enhancing wild stocks with hatchery-reared seed. We conducted two manipulative field experiments in the soft-bottom intertidal zone during 19901991 in eastern Maine to assess effects of predation, intraspecific competition, and initial planting size on the survival and growth of cultured individuals of Mya. Experiment I (23 June 1990 to 13 June 1991) tested interactive effects of two planting sizes (small=8.5 mm shell length (SL); large=11.8 mm SL) and protective netting on fate and growth of clams. Animals of each size were added to separate experimental units within each of 60 1-m(2) areas delimited by a wooden box. To deter predators, 50 boxes were covered with a specific type of plastic netting that differed in aperture size (4.2, 6.4 and 12.8 mm) and degree of rigidity (flexible vs. extruded) while 10 boxes served as controls (without netting). Small clams grew at a faster rate than large clams, but both added approximately 18 mm of new shell by the end of the study. Growth was unaffected by netting size and rigidity, but 13% more clams were recovered alive after a year in protected vs. unprotected treatments (84% vs. 71%). Survival was independent of netting type. The presence of netting resulted in nearly a 3 x enhancement of wild spat (