Trottier Oliver, Jeffs Andrew G
Leigh Marine Laboratory, University of Auckland, Warkworth 0941, New Zealand.
Dis Aquat Organ. 2012 Oct 10;101(1):61-8. doi: 10.3354/dao02504.
Pea crabs are commercially significant parasites in the aquaculture production of bivalves in many parts of the world. However, there is scant information available on the biology of these important parasites in aquaculture. The population structure, sex ratio, and breeding status were determined for the pea crab Nepinnotheres novaezelandiae residing in a typical green-lipped mussel Perna canaliculus farm in New Zealand. Of the 324 crabs randomly sampled, there were significantly more female (82.4%) than male (17.6%) crabs found. The vast majority of crabs (87.0%) were sexually mature and of these, females comprised 86.4% and males 13.6%. However, the sex ratio of immature crabs was relatively even, suggesting that male crabs may have higher mortality while searching for mates. Crab size was highly variable, indicating that recruitment to mussels in the farm was continuous. Carapace width ranged from 4.00 to 11.5 mm, with males tending to be smaller with a mean (±SE) carapace width of 6.31 ± 0.16 mm versus females with a carapace width of 8.03 ± 0.06 mm. The crabs did not show any preference for parasitizing mussels of different sexes. Despite the fact that the mussels were only 10 mo old, most female crabs were sexually mature (Stage V) and 89.3% were gravid. The mean (±SE) clutch size was 2592 ± 579 and clutch size was directly associated with female carapace width. The mussel farm pea crab population was estimated at 126390 ± 14144 individuals, including 93000 gravid females carrying a total of over 241 million eggs. Overall, the results show that pea crabs rapidly colonize farmed mussels and mature quickly to establish a significant breeding population within the mussel farm, with larval output capable of infecting nearby mussel farms as well as wild populations of bivalves.
豆蟹是世界许多地区双壳贝类水产养殖中具有商业重要性的寄生虫。然而，关于这些水产养殖中重要寄生虫的生物学信息却很少。对栖息在新西兰一个典型的绿唇贻贝养殖场的豆蟹新西兰新派内蟹的种群结构、性别比例和繁殖状况进行了测定。在随机抽取的324只蟹中，发现雌性蟹（82.4%）明显多于雄性蟹（17.6%）。绝大多数蟹（87.0%）已性成熟，其中雌性占86.4%，雄性占13.6%。然而，未成熟蟹的性别比例相对均匀，这表明雄性蟹在寻找配偶时可能死亡率较高。蟹的大小差异很大，这表明养殖场中贻贝的补充是持续的。头胸甲宽度在4.00至11.5毫米之间，雄性往往较小，平均（±标准误）头胸甲宽度为6.31±0.16毫米，而雌性头胸甲宽度为8.03±0.06毫米。这些蟹在寄生不同性别的贻贝方面没有表现出任何偏好。尽管贻贝只有10个月大，但大多数雌性蟹已性成熟（V期），89.3%怀有卵。平均（±标准误）卵块大小为2592±579，卵块大小与雌性头胸甲宽度直接相关。该贻贝养殖场的豆蟹种群估计有126390±14144只，其中包括93000只怀有卵的雌性蟹，总共携带超过2.41亿枚卵。总体而言，结果表明豆蟹能迅速在养殖贻贝中定殖并快速成熟，在贻贝养殖场内建立起大量繁殖种群，其幼虫产出能够感染附近的贻贝养殖场以及双壳贝类野生种群。
