New record of Japanese snake blenny Xiphasia matsubarai(Perciformes:Blenniidae) from South China Sea

Specimens belonging to the family Blenniidae were collected in a fishery resource investigation from the coastal waters of Xisha Islands and Hainan Island, South China Sea in 2016. Combining morphological results with sequence analysis, we identified one specimen as Xiphasia matsubarai Okada Suzuki, 1952. This represents a new record in the South China Sea. In morphology, the specimen has the following traits: body elongated, eel-like or ribbon-like in shape; flanks medium flat; the head small bluntly rounded anteriorly and without a moustache; eyes is slightly smaller, on upper lateral position of head, which is about equal to 1/5 of the length of the head; body without scales, lateral line has been degraded; both sides of the upper and lower jaws with a canine; gill is opening at the top of the pectoral fin base, approximately equal to the length of eye diameter. Dorsal fin Ⅺ, 96; pectoral fin 10; anal fin Ⅱ, 95. Head and body grey-brown, including 26 dark grey-brown bands; abdomen and lower operculum yellowish grey and colour lighter; and dorsal base long with dark grey. Origin of dorsal is located over the anterior margin of pupil; black blotch on dorsal fin between 8 th and 10 th dorsal spine; anal and caudal fins dark grey, pectoral and ventral fins pale yellow. Sequence analysis of cytochrome oxidase subunit I gene( COI) strongly supports the identity of the specimen as Ⅹ. matsubarai.     

海表温度对南沙海域鸢乌贼资源变动的影响

根据南沙海域2018—2019年鸢乌贼(Sthenoteuthis oualaniensis)灯光罩网渔获数据和海表温度(sea surface temperature, SST)遥感数据,研究SST对鸢乌贼资源变动的影响。经验正交函数分析(empirical orthogonal function, EOF)显示南沙海域SST季节变化明显,月均值在年内呈双峰型变化,峰值出现在5—6月和10月。2019年南沙海域发生厄尔尼诺,SST高温频率升高,年均值较2018年升高0.3℃。2018年鸢乌贼的单位捕捞努力量渔获量(catch per unit effort, CPUE)为春季(3—5月)高,夏季(6—7月)低,2019年CPUE为冬季(2月)高,夏季(6月)低。广义相加模型(generalized additive model, GAM)显示,月份、SST、纬度和经度4个因子对CPUE的总偏差解释度为55.0%,其中月份与SST的偏差解释度大于其他因子。鸢乌贼群体的适宜温度为27.5～29.5℃,SST超过29.5℃会导致CPUE降低。鸢乌贼渔场集中分布于10°N—12°N、113°...