Abstract Elasmobranchs represent one of the most imperiled taxa, yet few nations have developed catch limits and no international or bilateral catch limits exist. One barrier to establishing catch limits is a lack of accurate species-specific extraction rates due to many species looking similar, distinguishing characteristics (fins and head) being removed, or grouping of all elasmobranchs together in fisheries data. To better understand the species-specific impacts fisheries are having on elasmobranchs we used forensic genetic techniques to identify the types and quantities of shark species landed in Costa Rican artisanal small-scale and mid-scale fisheries. We collected elasmobranch tissue samples from fishermen in three locations along Costa Rica’s Pacific Coast: Coyote, Bejuco, and Ojochal, from April 2013 to September 2014. We used DNA barcoding techniques, utilizing a 1044 base pair region of the NADH dehydrogenase subunit 2 gene, to identify to species 275 of the 416 samples collected. Within these fisheries, seven species of shark and one ray were identified, with the scalloped hammerhead shark (Sphyrna lewini) accounting for ∼75−80% of all sharks landed. Observed total lengths (TL) for the scalloped hammerhead shark (10.9–99 cm) in these fisheries suggests the sharks sampled were all either juveniles or neonates. Based on these data it is likely that the areas from which these samples were collected represent nursery grounds for the scalloped hammerhead shark. The quantity of young scalloped hammerhead sharks removed from these areas, and ones similar to them, by these artisanal fisheries could be of great importance when determining future conservation measures for this species. Our findings also indicate that sharks caught in these artisanal fisheries do not appear to represent those sold in markets around San Jose.

中文翻译：

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对在哥斯达黎加手工渔业中登陆的软骨鱼进行法医物种鉴定

摘要 Elasmobranchs 是最危险的分类群之一，但很少有国家制定了捕捞限制，并且不存在国际或双边捕捞限制。建立捕捞限制的一个障碍是缺乏准确的特定物种提取率，因为许多物种看起来相似，区分特征（鳍和头部）被去除，或者在渔业数据中将所有的韧皮鱼分组在一起。为了更好地了解渔业对软骨鱼的特定物种影响，我们使用法医遗传技术来确定在哥斯达黎加手工小规模和中规模渔业中登陆的鲨鱼物种的类型和数量。2013 年 4 月至 2014 年 9 月，我们从哥斯达黎加太平洋沿岸三个地点的渔民身上收集了韧皮组织样本：Coyote、Bejuco 和 Ojochal。我们使用 DNA 条形码技术，利用 NADH 脱氢酶亚基 2 基因的 1044 个碱基对区域，对收集的 416 个样本中的 275 个物种进行鉴定。在这些渔业中，确定了 7 种鲨鱼和 1 种鳐鱼，扇形双髻鲨 (Sphyrna lewini) 占所有上岸鲨鱼的 75-80%。在这些渔业中观察到的扇形双髻鲨（10.9-99 厘米）的总长度 (TL) 表明采样的鲨鱼都是幼鱼或新生儿。根据这些数据，收集这些样本的区域很可能代表了扇贝双髻鲨的繁殖地。从这些区域移除的年轻扇贝双髻鲨的数量，以及与它们相似的数量，在确定该物种的未来保护措施时，这些手工渔业可能非常重要。我们的研究结果还表明，在这些手工渔业中捕获的鲨鱼似乎并不代表圣何塞附近市场上出售的鲨鱼。