Ali Muhammad Yousuf, Hossain Md Billal, Sana Sattyajit, Rouf Muhammad Abdur, Yasmin Sajeda, Sarower Md Golam
Fisheries and Marine Resource Technology Discipline, Khulna University, Khulna 9208, Bangladesh.
SDC-Shomoshti Project, CARE, Bangladesh.
Heliyon. 2020 Jun 28;6(6):e04318. doi: 10.1016/j.heliyon.2020.e04318. eCollection 2020 Jun.
Recently mud crab () has emerged as a potential export commodity. Its farming is increasing rapidly in Bangladesh because of its lucrative price and high demand in international market. However, the farming or fattening of mud crab is totally dependent on capture of wild crablets. A huge quantity of mud crabs is being caught indiscriminately from nature and thus putting intense pressure on its wild stock, which is a major concern of conservation. Imposing ban at peak breeding season and setting a legal capture size are considered effective management tools for safe migration and spawning of berried females. There is contradictory information on breeding season of mud crab in Bangladesh. Thus, it is crucial to identify the peak breeding season of it and to formulate conservation policies to protect the berried crabs. Live crabs were collected year-round from the river adjacent to southwest part of Sundarbans. Although mud crab breeds throughout the year, March-April was identified as the peak breeding season of it. The second peak was observed in August-September. The highest abundance of crablets (1-2 months age) was recorded in May-June, and the lowest in January-February. Immature crablets were found all through the year that proves that mud crab is a continuous breeder. The highest amount of GSI value (11.6) was observed in February-March, which indicates that the breeding is very near. The size at first maturity (M) was estimated as 95.5 mm CW which lied at size class 91-100 mm (CW). The findings from the study will assist in fixing up the banning time and thus protecting the mother crabs; and will assist in formulating police to conserve and protect juvenile crabs in the sense that the minimum legal capture size of crabs will allow the adults to mate and spawn at least once before their capture.
最近，青蟹已成为一种潜在的出口商品。由于其利润丰厚的价格和在国际市场上的高需求，其养殖在孟加拉国迅速增加。然而，青蟹的养殖或育肥完全依赖于捕获野生蟹苗。大量的青蟹被无差别地从自然界中捕获，从而对其野生种群造成了巨大压力，这是保护工作的一个主要问题。在繁殖高峰期实施禁令并设定合法捕获尺寸被认为是保障抱卵雌蟹安全洄游和产卵的有效管理工具。关于孟加拉国青蟹繁殖季节的信息存在矛盾。因此，确定其繁殖高峰期并制定保护抱卵蟹的保护政策至关重要。全年从孙德尔本斯西南部相邻的河流中采集活蟹。尽管青蟹全年都繁殖，但3月至4月被确定为其繁殖高峰期。第二个高峰期出现在8月至9月。蟹苗（1至2个月龄）数量最多的记录出现在5月至6月，最少的出现在1月至2月。全年都发现了未成熟的蟹苗，这证明青蟹是连续繁殖者。2月至3月观察到最高的性腺指数值（11.6），这表明繁殖即将来临。首次性成熟时的壳宽（M）估计为95.5毫米，处于91至100毫米（壳宽）的尺寸等级。该研究结果将有助于确定禁捕时间，从而保护母蟹；并有助于制定保护和保护幼蟹的政策，因为蟹类的最小合法捕获尺寸将使成年蟹在被捕前至少有一次交配和产卵的机会。
