Ellis J R, Burt G J, Grilli G, McCully Phillips S R, Catchpole T L, Maxwell D L
Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Pakefield Road, Lowestoft, Suffolk, NR33 0HT, U.K.
Centre for Social and Economic Research on the Global Environment (CSERGE), University of East Anglia, Norwich, Norfolk, NR4 7TJ, U.K.
J Fish Biol. 2018 Jun;92(6):1702-1719. doi: 10.1111/jfb.13597. Epub 2018 Apr 19.
Data on the vigour and at-vessel mortality (AVM) of 6798 skates (comprising Raja clavata n = 6295; R. brachyura n = 208; R. undulata n = 185, R. montagui n = 98 and R. microocellata n = 12) captured by commercial fishing vessels in the inshore waters of the southern North Sea and English Channel were recorded. AVM in longline fisheries averaged 0·44% across five vessels (0-1·47%), although skates were usually unhooked manually and did not usually pass through a bait-stripper. AVM in otter trawls averaged 0·76% (0-2·35%), from four vessels fishing with tow durations of <1·5 h (southern North Sea) or 1-4 h (English Channel). No AVM was noted for skates taken as a by-catch in drift trammel nets (soak times <4 h). Anchored tangle nets resulted in an overall AVM of 2·0-2·7%, but increased from 1·47% (13-28 h soak time) to 6·16% (42-53 h soak time). There were significant differences in the vigour of skates between gears, with R. clavata caught by longline and tangle nets in better condition than those captured by otter trawl or drift trammel net. Similarly, R. undulata caught by tangle net were in better condition than those caught by otter trawl. The vigour of R. undulata was also found to be higher than other skate species for both trawl and tangle net. In total, 5283 skates were tagged with Petersen discs and released, with recapture rates for the various combinations of vessel and gear ranging up to 24·8% for R. clavata. Whilst confirming a degree of post-release survival, quantitative estimates of post-release mortality for skates remain unknown.
记录了商业渔船在北海南部近岸水域和英吉利海峡捕获的6798条鳐鱼（包括孔鳐6295条、短吻鳐208条、波鳐185条、蒙塔古鳐98条和小眼鳐12条）的活力和在网具中的死亡率（AVM）。延绳钓渔业中，五艘船上鳐鱼的AVM平均为0.44%（0 - 1.47%），尽管鳐鱼通常是人工解钩，且通常不经过饵料剥离器。双拖网渔业中，四艘拖网时间小于1.5小时（北海南部）或1 - 4小时（英吉利海峡）的船只，鳐鱼的AVM平均为0.76%（0 - 2.35%）。在流刺网（浸泡时间小于4小时）中作为兼捕渔获的鳐鱼未发现AVM。锚定缠结网导致鳐鱼的总体AVM为2.0 - 2.7%，但浸泡时间从1.47%（13 - 28小时）增加到6.16%（42 - 53小时）。不同渔具捕获的鳐鱼活力存在显著差异，延绳钓和缠结网捕获的孔鳐状况优于双拖网或流刺网捕获的。同样，缠结网捕获波鳐的状况优于双拖网捕获的。还发现双拖网和缠结网捕获的波鳐活力均高于其他鳐鱼种类。总共5283条鳐鱼被标记上彼得森圆盘后放流，不同船只和渔具组合的孔鳐重捕率高达24.8%。虽然证实了放流后有一定的存活率，但鳐鱼放流后死亡率的定量估计仍不清楚。
