Spatial ecology and habitat partitioning of two sympatric ophichthid eel species in the Gulf of Mexico

Ophichthid eel species are abundant and diverse in tropical and semitropical seas but there are few studies of snake eel life histories and factors influencing spatial distributions. Here we analyze 12 demersal longline sampling expeditions circumnavigating continental shelves in the Gulf of Mexico (GoM) during 2011-2017. Two ophichthid eels were dominant components of fish assemblages: king snake eel (KSE), Ophichthus rex, and palespotted eel (PSE), Ophichthus puncticeps. Relative abundance (CPUE) of KSE was highest in the north central GoM, lower in the northwest and southeast and on the West Florida Shelf, and absent from northwest Cuba and the Yucatan Platform. Contrariwise, PSE abundance was highest on the Yucatan Platform, lower in the north central GoM and on the West Florida Shelf, and absent from the northwest and southwest GoM and Cuba. GAM-based species distribution models were fit to presence-absence data from sampled stations using a variety of environmental covariates including water depth, longitude, and sediment type (sand vs mud/silt). Although the two species were caught in similar depths and bottom temperatures, they were only caught together at 1% of the stations. This study extends the record length of KSE to 226 cm (total length). Despite being abundant in areas overlapping the footprint of the Deepwater Horizon oil spill in 2010, concentrations of polycyclic aromatic hydrocarbons (PAHs) and their metabolites were relatively low in KSE, perhaps related to copious slime production which, in other studies, has been determined to be a vector for PAH excretion in fishes.