Abstract

Disease can alter population structure in terrestrial ecosystems but only anecdotal evidence exists for these effects in the marine environment. PaV1 (Panulirus argus virus 1) is a pathogenic virus transmitted between Caribbean spiny lobsters, Panulirus argus (Latrielle 1804). However, P. argus can reduce infection risk by avoiding PaV1-infected lobsters. Avoiding shelters inhabited by PaV1-infected conspecifics has the potential to significantly alter population structure and local spatial distribution, resulting in shelter exclusion and increased predation. However, based on the type of avoidance cue, local hydrodynamic conditions could affect detection. We used a series of laboratory y-maze experiments to determine the mechanism of detection and artificial shelter arrays placed in low and high flow conditions in the wild to determine the effect of diseased lobster aversion on healthy lobster population dynamics. Results showed that avoidance was driven by olfactory cues based in the urine. The olfactory cue alone was equally effective having a diseased lobster present and visible. In the field, PaV1 can alter the spatial structure of wild populations especially under low flow regimes via emigration and the redistribution of uninfected individuals relative to diseased animals. In the shelter-limited environments common throughout much of the Caribbean, disease avoidance has the potential to increase juvenile mortality and negatively impact future adult stocks as uninfected animals are displaced from dens and exposed to a higher risk of predation.