Decapod fisheries and parasite species richness: an exploration of host traits and parasitic influence

Some hosts harbor more parasites than
others. Overdispersion of parasitism suggests that
coevolution with parasites may be more important to
the biology and ecology of certain species. We examined patterns of parasitism and host traits in fished
decapod crustaceans, which are economically and
ecologically important worldwide. Using a synthesis
approach, we determine that host life history, including habitat, longevity, sociality, invasion history, and
fisheries involvement, correlate with the number and
type of parasite species harbored. Indicator species
analysis revealed close relationships between decapods and certain parasite groups, including crabs
with rhizocephalans and dinofagellates; crayfsh
with mesomycetozoans, oomycetes, branchiobdellids, and fungi; lobsters with copepods and amoebae; and
shrimp with viruses. In contrast, Nematomorpha and
Nemertea appear to be under-represented and understudied as parasite groups in decapods. Decapods that
are commercially fished, aquacultured, introduced
outside their native range, and/or exhibit parental care
tend to have higher parasite species richness (PSR).
Parasite richness also increases with how well-studied
a host group is, which we addressed with a machine
learning algorithm that predicts false negative associations. Geographic range is commonly positively correlated with parasite richness, however reliable ranges
are not available for most decapod species, highlighting a signifcant future research need. Identifying patterns such as these increases our broad understanding
of decapod disease ecology but also enabled us to
develop a series of recommendations on how to focus future research, management, and aquaculture development efforts