ABSTRACT

Marine fish stocks are increasingly being exploited to unsustainable levels. Yet, knowledge of basic biological and ecological traits of species, required to sustain fisheries management at a local scale, remains scarce. We investigated the reproductive biology and growth of two marine catfishes: rough-head sea catfish (Arius latiscutatus) and Guinean sea catfish (Carlarius parkii). Both species showed one spawning season between May and June. Nevertheless, as these are mouth brooding species, we have considered that the reproduction season may be underway until August. Mean fork length of females at first maturity was ∼40 cm for A. latiscutatus and 35 cm for C. parkii, corresponding to 4–5 years for both species. Higher fecundity was found in larger females, with a mean of 45 and 26 eggs for A. latiscutatus and C. parkii, respectively. Differences recorded in sex ratio throughout the year suggest that females can leave the study area after the spawning season or that differences in behaviour may lead to differential sex catchability. The two species showed similar growth curves, despite A. latiscutatus reaching larger lengths at the same age. Estimated length–weight relationships suggest that both species present a positive isometric growth pattern. Our results highlight the slow life-history strategy of the two studied catfish species, thus emphasizing their vulnerability to fishing activities. We suggest that a short-term fishing closure during the spawning period (May–June) in the PNBA may be an important management measure to ensure reproduction opportunities for both species and, therefore, guarantee fishing sustainability.

摘要

海洋鱼类资源正日益被开发到不可持续的水平。但是，对于维持地方规模的渔业管理所需要的物种基本生物和生态特征的知识仍然匮乏。我们研究了两种海洋cat鱼的生殖生物学和生长：粗头sea鱼（Arius latiscutatus）和几内亚sea鱼（Carlarius parkii）。这两个物种在五月到六月之间都显示出一个产卵季节。然而，由于这些是令人垂涎的物种，我们认为繁殖季节可能一直持续到八月。首次成熟时雌性的平均叉长为阔叶曲霉为40厘米，柏氏曲霉为35厘米。，对应于两个物种的4-5年。在较大的雌性中发现较高的繁殖力，A。latiscutatus和C. parkii分别平均有45和26个卵。全年的性别比差异表明，雌性可以在产卵季节结束后离开研究区域，或者行为上的差异可能会导致不同的性别可捕获性。尽管有阔叶曲霉，但两个物种的生长曲线相似。在同一年龄段达到更大的长度。估计的长度与重量的关系表明，这两种物种都呈现出正等距的生长模式。我们的结果强调了这两种研究过的cat鱼物种的缓慢的生活史策略，从而强调了它们对捕捞活动的脆弱性。我们建议在PNBA产卵期（5月至6月）进行短期捕捞可能是一项重要的管理措施，以确保两个物种的繁殖机会，从而保证捕捞的可持续性。