Temperature-dependent effects of sea-louse infestation on juvenile Atlantic salmon

Infectious diseases are key drivers of wildlife populations and
agriculture production, but whether and how climate change will influence
disease impacts remains controversial. One of the critical knowledge gaps
that prevents resolution of this controversy is a lack of high-quality
experimental data, especially in marine systems of significant ecological
and economic consequence. Here, we performed a manipulative experiment in
which we tested the temperature-dependent effects on Atlantic salmon
(Salmo salar) of sea lice (Lepeophtheirus salmonis) – a parasite that can
depress the productivity of wild-salmon populations and the profits of the
salmon-farming industry. We explored sea-louse impacts on their hosts
across a range of temperatures (10, 13, 16, 19, and 22 °C) and infestation
levels (zero, ‘low’ (mean abundance ± SE = 1.6 ± 0.1 lice per fish), and
‘high’ infestation (6.8 ± 0.4 lice per fish)). We found that the effects
of sea lice on the growth rate, condition, and survival of juvenile
Atlantic salmon all worsen with increasing temperature. Our results
provide a rare empirical example of how climate change may influence the
impacts of marine disease in a key social-ecological system. These
findings underscore the importance of considering climate-driven changes
to disease impacts in wildlife conservation and agriculture. This
Dryad submission includes the growth-rate, condition, and
survival data for the manuscript entitled "Increasing
temperatures accentuate negative fitness consequences of a marine
parasite" by Sean C. Godwin, Mark D. Fast, Anna Kuparinen,
Kate E. Medcalf, and Jeffrey A. Hutchings.