Imsland Albert Kjartan Dagbjartarson, Hanssen Anna, Nytrø Ane Vigdisdatter, Reynolds Patrick, Jonassen Thor Magne, Hangstad Thor Arne, Elvegård Tor Anders, Urskog Tonje Cecilie, Mikalsen Bjørn
Akvaplan-niva Iceland Office, Akralind 4, 201 Kópavogur, Iceland
Department of Biology, University of Bergen, High Technology Centre, 5020 Bergen, Norway.
Biol Open. 2018 Sep 3;7(9):bio036301. doi: 10.1242/bio.036301.
To assess the efficacy of lumpfish grazing on attached sea lice on Atlantic salmon, six large-scale sea cages, (130 m circumference, 37,688 m volume) each stocked with approximately 200,000 salmon 0+ smolts, were stocked with a 4, 6 and 8% density (8000, 12,000 and 16,000, respectively) of lumpfish. The sea cages without lumpfish acted as controls. Sea lice infestation levels on the salmon were monitored weekly and bi-weekly from 6 October to 17 May the subsequent year. Mortality of the lumpfish rose with decreasing sea temperatures to around 0.8% week and did not vary between the lumpfish groups. There were clear signs of lumpfish grazing on sea lice, with significantly lower average levels of chalimus, pre-adult and adult female and sea lice per salmon. Lumpfish in the high density (8%) group reduced the mature female to levels equal to or lower than the counts recorded prior to the start of the study. Overall, the present results indicate that lumpfish are a suitable cold-water option for biological delousing of Atlantic salmon in large-scale production conditions.
为评估圆鳍鱼对大西洋鲑鱼体表附着海虱的捕食效果，六个大型海水网箱（周长130米，容积37688立方米），每个网箱放养约200000尾0+规格的鲑鱼幼鱼，并分别以4%、6%和8%的密度（分别为8000尾、12000尾和16000尾）放养圆鳍鱼。未放养圆鳍鱼的海水网箱作为对照。从10月6日至次年5月17日，每周和每两周监测鲑鱼的海虱感染水平。随着水温下降，圆鳍鱼的死亡率升至约每周0.8%，且不同圆鳍鱼组之间没有差异。有明显迹象表明圆鳍鱼捕食了海虱，每条鲑鱼上的海鲺、未成熟海虱和成年雌虱的平均数量显著降低。高密度（8%）组的圆鳍鱼将成熟雌虱数量降至等于或低于研究开始前记录的数量。总体而言，目前的结果表明，在大规模养殖条件下，圆鳍鱼是大西洋鲑鱼生物除虱的合适冷水选择。
