IMPROVING DIET RESOLUTION FOR REEF-ASSOCIATED LARGE PISCIVOROUS PREDATORS IN THE U.S. SOUTHEAST ATLANTIC USING MOLECULAR TOOLS
The importance of predator-prey interactions on marine fish populations has been recognized for quite some time. Since it is suggested that predation mortality rates often exceed fishing mortality rates, consideration in fisheries management is imperative. Diet studies rapidly are becoming a common practice of fisheries ecology, and are able to provide valuable insight on competition for resources, habitat use, energy flow, natural mortality, and seasonal variability that is essential for emerging ecosystem-based fishery management models. Many large, piscivorous predators in the U.S. Southeast Atlantic (USSA) exhibit high digestion rates, and consequently their prey items are commonly unable to be visually confirmed through traditional morphological analysis techniques. The current study combined both visual and molecular diet analysis techniques to increase taxonomic resolution for inter- and intra-specific diet composition for an assemblage of large, reef-associated, piscivorous predators from the USSA. Additionally, potential effects of environmental and physical variation on diet composition were examined using Canonical Correspondence Analysis. In total, 32 unique piscine prey species and 18 families were identified across all predators when using DNA barcoding, compared to 5 unique species and 10 families when using traditional visual methods. Increased taxonomic resolution determined predation levels on other managed species, identified important prey species, and elucidated potential competitive interactions in the diets of Red Snapper, Scamp, Gag, Red Grouper, and Snowy Grouper in the USSA.