Effects of stochastic environmental variation on the population dynamics of salmon lice (Lepeophtheirus salmonis) in Newfoundland and Labrador

• Main Author: Prosser, Jacob T.
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2022
• Subjects: Canada; Newfoundland
• Online Access: https://research.library.mun.ca/15559/; https://research.library.mun.ca/15559/1/thesis.pdf

Salmon lice Lepeophtheirus salmonis are a marine parasite causing a significant economic burden in salmonid aquaculture. They experience both temperature-dependent growth and salinity-dependent mortality, impacting population dynamics. Many models have explored the effect of static or seasonal environmental conditions on salmon lice population dynamics, yet none have explored the impact of short-term daily environmental fluctuations. I derived a stochastic population model with daily variability in temperature and salinity, where these fluctuations effect population dynamics through temperature-dependent maturation and salinity-dependent mortality changes. I found that increasing variability in salinity slows population growth rates and decreases the logarithmic abundance of adult females, while increasing daily variability in temperature is a poor indicator of population dynamics, which is better predicted by seasonal temperature trends. Under all stochastic environmental scenarios salmon lice populations persisted and grew in Newfoundland, Canada. Population models are a valuable tool in the management of salmon lice and allow for more sustainable aquaculture practices.