McDonald P S., Jensen G C., Armstrong D A.
School of Aquatic and Fishery Sciences, Box 355020, University of Washington, 98195, Seattle, WA, USA
J Exp Mar Biol Ecol. 2001 Mar 30;258(1):39-54. doi: 10.1016/s0022-0981(00)00344-0.
We evaluate the potential competitive and predatory impacts of nonindigenous European green crab Carcinus maenas on native Dungeness crab Cancer magister in the northeast Pacific. The coastal estuaries of Washington State, USA, provide appropriate habitat for recently introduced green crab, yet these areas are important nursery grounds for Dungeness crab and contribute greatly to the coastal crab fishery. Juvenile Dungeness crabs are dependent on limited intertidal epibenthic shell for refuge habitat during early benthic life and experience increased mortality on open sand and mud as a result of predation by fish and birds. Early juveniles throughout the subtidal are similarly at risk due to predation by fish and especially adult conspecifics. Laboratory experiments and infrared video observations revealed that juvenile green crab displace Dungeness crab of equal size from shelters during one-on-one competition. Green crab also consistently win nocturnal foraging trials in which the species compete for fresh, damaged clams. Field and laboratory enclosure experiments show that juvenile Dungeness crab emigrate from oyster shell habitat as a result of competition and predation by adult green crab. Depending on the extent to which the two species overlap, interactions with the dominant nonindigenous species could have a negative influence on juvenile Dungeness crab survival and could conceivably impact recruitment to the fishery. However, current evidence indicates that the distribution of green crab in Washington State is far removed from nursery areas of Dungeness crab.
我们评估了非本土的欧洲绿蟹（Carcinus maenas）对东北太平洋本土珍宝蟹（Cancer magister）的潜在竞争和捕食影响。美国华盛顿州的沿海河口为最近引入的绿蟹提供了适宜的栖息地，但这些区域是珍宝蟹重要的育幼场，对沿海蟹类渔业贡献巨大。幼年珍宝蟹在底栖生活早期依赖有限的潮间带表栖贝壳作为避难栖息地，而由于鱼类和鸟类的捕食，它们在开阔沙地和泥地的死亡率会增加。潮下带的早期幼蟹同样因鱼类尤其是成年同类的捕食而面临风险。实验室实验和红外视频观察表明，在一对一竞争中，幼年绿蟹会将同等大小的珍宝蟹从庇护所中赶走。绿蟹在争夺新鲜破损蛤蜊的夜间觅食试验中也始终获胜。野外和实验室围隔实验表明，由于成年绿蟹的竞争和捕食，幼年珍宝蟹会从牡蛎壳栖息地迁出。根据这两个物种的重叠程度，与占主导地位的非本土物种的相互作用可能会对幼年珍宝蟹的生存产生负面影响，并可能会影响渔业的补充量。然而，目前的证据表明，华盛顿州绿蟹的分布与珍宝蟹的育幼区相距甚远。
