ABSTRACT: Juvenile blue crabs Callinectes sapidus use seagrass and other structured habitats as refuges from predation. Oyster reef habitats provide structural complexity that may offer refuge, but the value of these habitats for juvenile blue crabs has not been examined. We quantified survival of juvenile C. sapidus in structured oyster reef habitat versus unstructured soft-bottom habitat. In a field tethering experiment in the York River, lower Chesapeake Bay (USA), juvenile C. sapidus (10-50 mm carapace width [CW]) were tethered in sand (n = 40) or oyster reef (n = 39) habitats at subtidal sites 1-2 m deep. An underwater camera system was used to record predation activity during 24 h trials. Juvenile crab survival was significantly higher on the oyster reef habitat (53.8%) than on bare sand (15.0%), and tended to increase with crab CW in both habitats. The main successful predators on juvenile blue crabs were northern pufferfish Sphoeroides maculatus in the oyster reef habitat and adult blue crabs in the sand habitat. The high survival rate of juvenile C. sapidus in oyster reef habitats suggests that oyster reefs include physical habitat complexity that may offer refuge from predators. Restored and natural oyster reefs could provide an alternative nursery habitat for juvenile blue crabs, expanding the ecosystem services provided by restored oyster reefs.

中文翻译：

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被贝壳拯救：牡蛎礁可以保护幼年蓝蟹 Callinectes sapidus

摘要：幼年蓝蟹Callinectes sapidus使用海草和其他结构化栖息地作为躲避捕食的避难所。牡蛎礁栖息地提供可能提供避难所的结构复杂性，但尚未研究这些栖息地对幼年蓝蟹的价值。我们量化了结构化牡蛎礁栖息地与非结构化软底栖息地中C. sapidus幼鱼的存活率。在约克河的野外系留实验中，切萨皮克湾下游（美国），幼体C. sapidus（10-50 毫米的甲壳宽度 [CW]）被拴在 1-2 m 深的潮下带的沙子（n = 40）或牡蛎礁（n = 39）栖息地中。水下相机系统用于记录 24 小时试验期间的捕食活动。牡蛎礁栖息地的幼蟹存活率 (53.8%) 显着高于裸沙 (15.0%)，并且在这两个栖息地中随着螃蟹 CW 的增加而增加。幼年蓝蟹的主要成功捕食者是牡蛎礁栖息地的北方河豚Shoeroides maculatus和沙地栖息地的成年蓝蟹。C. sapidus幼鱼成活率高在牡蛎礁栖息地表明牡蛎礁包括可能为捕食者提供避难所的物理栖息地复杂性。恢复的天然牡蛎礁可以为幼年蓝蟹提供替代的育苗栖息地，扩大恢复牡蛎礁提供的生态系统服务。