The largest estuary in the United States, Chesapeake Bay is a mixing pot for freshwater, estuarine, and marine species. The Bay has experienced intense and disruptive historical and contemporary human activity and thus is a focal point for the conservation and restoration of free-living biodiversity. But what about Chesapeake Bay’s parasites? Has parasite biodiversity changed with the environment and the free-living community? What might a “restored” Chesapeake Bay parasite community look like? To begin answering these questions, we performed an in-depth exploration of known Chesapeake Bay parasite biodiversity and identified the knowledge gaps that deserve future study. Using extensive databases for cartilaginous and boney fish host species and their helminth parasites (i.e., FishBase and FishPest), we compiled a probable Chesapeake Bay fish–parasite network, and we used generalized linear models to describe known parasite biodiversity patterns in this network. We also identified the host species that lack relevant parasitological data and estimated the number of parasite species that might be missing with their missing host species. Finally, we used the VertNet database to quantify the number of existing fish museum specimens that might be used to fill in existing knowledge gaps.
Results/Conclusions
The FishPest database contained 440 known Nearctic parasite species from 84 fish host species associated with Chesapeake Bay. On average, there were nine known parasite species per host species, four of which were unique to that host species within this network. Both total and specialist parasite richness were negatively correlated with host growth rate, and there were no other significant correlations between parasite richness and host characteristics. Surprisingly, half (90/174) of the fish species associated with Chesapeake Bay had no recorded Nearctic parasites in the FishPest database. Twenty-four of those missing host species were near threatened, threatened, or data deficient, and there was a marginally significant trend for host species of conservation concern to be more likely to be missing from the database. Overall, our Chesapeake Bay host–parasite network, which is based on the best available data, is likely missing many unique parasite species and host–parasite linkages. Those missing nodes and links could be discovered by strategically dissecting some of the 23,000 fluid-preserved fish specimens collected from Chesapeake Bay between 1860 and 2015. Dissections and other historical explorations that complete this network will be important steps in quantifying, conserving, and restoring Chesapeake Bay’s rich biodiversity.