Mate limitation in sea lice infesting wild salmon hosts: the influence of parasite sex ratio and aggregation

• DOI: 10.1002/ecs2.2040
• Publication Date: 2017-12-27T18:53:08Z
• Authors: R. Cox; M. L. Groner; C. D. Todd; G. Gettinby; T. Patanasatienkul; C. W. Revie
• Keywords: Lepeophtheirus; Louse; Allee effect

Abstract Mate limitation in dioecious parasite species has the potential to impact population growth. Our focus of interest was influence sex distribution among hosts on reproduction and transmission dynamics for populations ectoparasitic sea lice ( Lepeophtheirus salmonis Krøyer) establishing wild juvenile salmon hosts. The data included more than 139,000 out‐migrating pink Oncorhynchus gorbuscha (Walbaum)) chum keta British Columbia, Canada, sampled over nine years. For almost all years, ratio reproductive stages female‐biased. probability a female being able mate (i.e., attached fish also carrying male louse) increased with increasing abundance aggregation. We compared, expected modeling predictions, observed prevalence pairs one louse each sex) given mate. These comparisons showed that tend be distributed together rather separately Distribution means are randomly according common negative binomial distribution, whereas males females their own Despite tendency we found that, every year, at least 30% experience limitation. This Allee effect will result submaximal rates low abundances may limit transmission. work important implications management health both captive farm migratory stocks. More broadly, these results demonstrate as constraint establishment spread ectoparasite populations.