McEwan Gregor F, Groner Maya L, Cohen Allegra A B, Imsland Albert K D, Revie Crawford W
Department of Health Management, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada.
Dis Aquat Organ. 2019 Feb 21;133(1):69-82. doi: 10.3354/dao03329.
Atlantic salmon farming is one of the largest aquaculture sectors in the world. A major impact on farm economics, fish welfare and, potentially, nearby wild salmonid populations, is the sea louse ectoparasite Lepeophtheirus salmonis. Sea louse infestations are most often controlled through application of chemicals, but in most farming regions, sea lice have evolved resistance to the small set of available chemicals. Therefore, alternative treatment methodologies are becoming more widely used. One increasingly common alternative treatment involves the co-culture of farmed salmon with cleaner fish, which prey on sea lice. However, despite their wide use, little is understood about the situations in which cleaner fish are most effective. For example, previous work suggests that a low parasite density results in sea lice finding it difficult to acquire mates, reducing fecundity and population growth. Other work suggests that environmental conditions such as temperature and external sea louse pressure have substantial impact on this mate limitation threshold and may even remove the effect entirely. We used an Agent-Based Model (ABM) to simulate cleaner fish on a salmon farm to explore interactions between sea louse mating behaviour, cleaner fish feeding rate, temperature and external sea louse pressure. We found that sea louse mating has a substantial effect on sea louse infestations under a variety of environmental conditions. Our results suggest that cleaner fish can control sea louse infestations most effectively by maintaining the population below critical density thresholds.
大西洋鲑鱼养殖是世界上最大的水产养殖部门之一。海虱这种体外寄生虫对养殖场经济、鱼类健康以及附近野生鲑鱼种群都可能产生重大影响。海虱感染通常通过使用化学药物来控制，但在大多数养殖区域，海虱已经对少数几种可用化学药物产生了抗药性。因此，替代治疗方法正被越来越广泛地使用。一种越来越常见的替代方法是将养殖鲑鱼与清洁鱼混养，清洁鱼以海虱为食。然而，尽管清洁鱼被广泛使用，但人们对其最有效的情况了解甚少。例如，先前的研究表明，寄生虫密度低会导致海虱难以找到配偶，从而降低繁殖力和种群增长。其他研究表明，温度和外部海虱压力等环境条件对这种配偶限制阈值有重大影响，甚至可能完全消除这种影响。我们使用基于主体的模型（ABM）来模拟鲑鱼养殖场中的清洁鱼，以探索海虱交配行为、清洁鱼摄食率、温度和外部海虱压力之间的相互作用。我们发现，在各种环境条件下，海虱交配对海虱感染有重大影响。我们的结果表明，清洁鱼可以通过将海虱种群维持在临界密度阈值以下来最有效地控制海虱感染。
