Abstract:
Sea lice are marine ectoparasitic copepods. Commonly found in European and North American waters, these species have caused extensive ecological and economic damage in salmonid aquaculture. The significant impacts of sea lice in farm and wild fish populations has been the key drivers in the rising number of studies on sea lice infestations. While the effects of various environmental factors on the local dispersion patterns and transmission dynamics of sea lice have been observed, the lack of studies on the global sea lice niche have limited our understanding of the effects of climate warming on their distribution and ecology. Building on the existing knowledge of sea lice ecology, response to temperature changes, and their relationships with their fish hosts, I predicted the niche of two sea lice species, Lepeophtheirus salmonis and Caligus elongatus.
The MaxEnt models predicted a contraction in the L. salmonis niche range from the past (“Last Glacial Maximum” 22,000 years ago) to the present, but an expansion from the present to the future (year 2100). Distance from land and SST were the primary variables regulating the distribution of L. salmonis. For C. elongatus, the models predicted an expansion from the past to the present, but a contraction from the present to the future. Depth and SST were the primary variable regulating the distribution of C. elongatus. A consequence of these changes on salmon farm management is that farms may become more likely to experience sea lice infestation in the future, particularly by L. salmonis, which may lead to additional ecological and economic impacts in the future. However, additional research is necessary to examine the long-term effects of climate change on the host-parasite system between salmonids and sea lice.
