Assessing heritable variation in biological control of the salmon louse by two species of cleaner fish and co-operative behaviour by their client, Atlantic salmon

水族馆现在生产加拿大人消费的所有大西洋鲑鱼，以及大量的出口。鲑鱼虱是桡足类动物的一种海洋寄生虫，皮肤和鳃损伤造成的库存损失也会增加疾病风险，从而对农场收入产生直接影响。海虱侵扰的水平在历史上控制使用畜牧业的做法，包括区域管理和较低的放养密度。有限数量的化学治疗剂已被授权使用，但仅依赖这些杀寄生虫剂可能导致海虱抗药性。该行业现已采用综合虫害管理方法来管理海虱，该方法使用几种替代治疗方案。在欧洲，清洁鱼类，如圆鳍鱼和欧洲濑鱼被引入海笼，以吃大西洋鲑鱼上的虱子。在加拿大东部，圆鱼和一种北美濑鱼，cunner，已经被证明可以显着减少生活在海洋网箱中的鲑鱼上的成年虱子密度。此外，一些家庭的圆鱼是更有效的虱子清洁比其他人表明虱子清洁倾向是遗传的。目前还不清楚鲑鱼的合作行为（例如，保持静止），以促进虱子清洁曾经发生在海笼，如果是这样的行为是否是遗传的。用高密度SNP（单核苷酸多态性）芯片对大西洋鲑鱼进行基因分型，发现在没有清洁鱼的情况下，SNP与较低的虱子数量相关。我们的建议有以下目标：1）确定用于在商业海笼中清洁大西洋鲑鱼的最佳尺寸级的cunners; 2）确定种群结构，并检查来自不同种群的cunners和lumpfish之间的虱子清洁性能的差异; 3）评估cunners和lumpfish家族之间虱子进食行为的遗传差异; 4）在存在和不存在虱清洁鱼的情况下进行虱攻击，以查看在存在和不存在生物防治剂的情况下鲑鱼家族相对于虱计数的排名是否有变化。我们的工作将减少加拿大大西洋鲑鱼业控制海虱的经济成本，并提高其可持续性。

Aquaculture now produces all the Atlantic salmon consumed by Canadians as well as a significant amount for export. The salmon louse is a marine parasitic species of copepod that has a direct impact on farm income through inventory losses caused by skin and gill damage which can also increase disease risks. Levels of sea lice infestation were historically controlled using husbandry practices including area management and lower stocking densities. A limited number of chemical therapeutants have been authorized for use but sole reliance on these parasiticides can lead to sea lice resistance. The industry has now adopted an Integrated Pest Management approach to sea lice management, which uses several alternate treatment options. In Europe, cleaner fishes such as the lumpfish and European wrasses are introduced into sea cages to eat the lice off the Atlantic salmon. In eastern Canada, the lumpfish and a North American wrasse, the cunner, have been shownto significantly reduce adult lice densities on salmon living in marine sea cages. Further some families of lumpfish are more effective lice cleaners than others suggesting lice cleaning propensity is heritable. It is unknown whether co-operative behaviour by salmon (e.g., remaining stationary) to facilitate lice cleaning ever occurs in sea cages, and if so whether the behaviour is heritable. Genotyping Atlantic salmon with high density SNP (Single Nucleotide Polymorphisms) chips has revealed SNPs associated with lower lice counts in the absence of cleaner fish. Our proposal has the following objectives: 1) determine the best size-class of cunners to use to clean Atlantic salmon in commercial sea cages; 2) determine the stock structure and examine variation in lice-cleaning performance among cunners and among lumpfish from different stocks; 3) assess heritable variation in lice eating behaviour among families of cunners and of lumpfish; 4) Conduct lice challenges with and without the lice cleaner fish present to see if there is a change in the ranking of salmon families with respect to lice counts with and without the biological control agent present. Our work will reduce the economic costs of sea lice control by the Canadian Atlantic salmon industry and increase its sustainability.