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拟锥齿鲨是热带大西洋金枪鱼延绳钓渔业中较为常见的兼捕物种,处于海洋生态系统的顶端,对维持海洋生态系统的稳定性和多样性起着非常重要的作用。根据我国金枪鱼渔业国家观察员2010—2015年在热带大西洋海域调查时收集的1 561尾拟锥齿鲨数据,对其资源动态和空间分布进行了初步分析,结果表明:在研究的海域内(6.33°S~17.43°N,18.25°W~42.03°W),拟锥齿鲨CPUE高的区域为5°N~10°N,20°W~30°W;2010—2015年CPUE呈现波动,整体有上升的趋势,但不显著;软骨鱼类占总渔获物的比例整体呈下降趋势;拟锥齿鲨兼捕数量占总渔获的5.8%,占兼捕软骨鱼类的22.5%;拟锥齿鲨在12月—3月的平均CPUE较高。拟锥齿鲨最大叉长组(叉长范围在85~90 cm)的个体多分布在5°N~7.5°N,27.5°W~37.5°W和5°N~0°,25°W~30°W这两个区域。拟锥齿鲨理论钩获深度范围为140~313 m,平均深度为221 m。1、2、3钩位(140~212 m)的上钩频率最大,占总上钩率的55.59%。10月至次年4月不同月份拟锥齿鲨的钩位分布没有显著性的差异。妊娠期拟锥齿鲨明显分布于较浅的水层。不同钩位拟锥齿鲨的摄食等级无显著性差异。
Quasi-beaked sharks are the more common bycatch species in the longline fishery of tropical Atlantic tuna and are at the top of marine ecosystems. They play a very important role in maintaining the stability and diversity of marine ecosystems. According to the data of 1 561 bevel sharks collected by the national observers of tuna fishery in the tropical Atlantic Ocean from 2010 to 2015, the dynamic and spatial distribution of resources were analyzed. The results show that in the studied waters (6.33 ° S ~ 17.43 ° N, 18.25 ° W ~ 42.03 ° W). The area of CPUE with high bevel sharks ranged from 5 ° N to 10 ° N and from 20 ° W to 30 ° W. The CPUE fluctuated from 2010 to 2015, The proportion of cartilaginous fish in total catches showed a downward trend; the number of beached shark bycatch accounted for 5.8% of the total catch, accounting for 22.5% of the catch of cartilaginous fish; Tooth sharks have higher average CPUEs in December-March. The individuals with the largest length of fork group (range of 85 ~ 90 cm fork length) were distributed in the range of 5 ° N ~ 7.5 ° N, 27.5 ° W ~ 37.5 ° W and 5 ° N ~ 0 °, 25 ° W ~ 30 ° W these two areas. Quasi-cone shark theory hooked depth range of 140 ~ 313 m, the average depth of 221 m. 1, 2 and 3 hooks (140 ~ 212 m) had the highest hooking frequency, accounting for 55.59% of the total hooking rate. There was no significant difference in the distribution of the hook position of bevel sharks from October to April in different months. Quasi conical shark pregnancy significantly distributed in the shallow water layer. There was no significant difference in the feeding level of bevel sharks with different hook positions.