Nematode Community Structure and Biodiversity in Relation to Submerged Aquatic Vegetation at Currituck Sound, North Carolina

Submerged Aquatic Vegetation (SAV) in coastal habitats plays critical roles because it protects coastlines, prevents erosion, provides nursery habitat, and dissolved oxygen. Meiobenthic communities in these habitats also play a key role in ecosystems processes. However, currently SAV loss continues unabated globally. Our understanding of the impact this loss has on meiobenthic communities is limited. To assess the impact of SAV cover on nematode communities, we studied nematode communities at Currituck Sound, NC, by comparing communities at an unvegetated and at an SAV site. Nematodes were identified to genus level morphologically. Our results showed that general diversity was low compared to other comparable sites with only 10 genera at both sites. Diversity and community structure were distinct at the two sites indicating that submerged aquatic vegetation may impact community structure of nematodes.

Ontogeny of Otolith Formation in Two Demersal Estuarine Reef Fishes

Planktonic reef fish larvae locate and orient to reefs during settlement. Consequently, metamorphosis occurs in appropriate juvenile and/or adult habitats. Larval fish use otoliths for hearing (sagittae and asterisci) as well as equilibrium (lapilli) required for directional swimming. Striped blenny (Chasmodes bosquianus) and naked goby (Gobiosoma bosc) larvae, settled individuals, and juveniles were used to describe otolith ontogeny from hatching through settlement, the transition from pelagic to benthic habitats, and metamorphosis. Larvae hatched from nests collected in North Inlet estuary, SC, were cultured from May through July in 2012 and 2013 at ambient temperatures. Sagittae and lapilli were present at hatching in both species. Asterisci were only observed in settlement (gobies and blennies) or metamorphosis (blennies) stage fishes, regardless of age (days post-hatch). Otoliths within a pair were symmetrical. Fish total length increased faster than sagittae otolith length in settlement stage blennies and postflexion gobies. The allometric model explained ∼90% of the variability in sagittae otolith length with total length for both species. Settlement occurred 15–20 days post-hatch in striped blennies and 19–27 days post-hatch in naked gobies. Asterisci were found in 100% of settlement stage striped blennies and 67% of naked gobies. We hypothesize that the presence of asterisci in settlement stage demersal oyster reef fishes facilitates identification of and orientation to suitable settlement habitats thereby enhancing recruitment success.

Scavenging Behavior of the Aquatic Eastern Hellbender Salamander (Cryptobranchus Alleganiensis) in North Carolina

Vertebrates may scavenge, or utilize carrion resources more than has been widely assumed (Devault et al. 2003). While documentation of scavengers in terrestrial and marine systems has received increased attention (Beasley et al. 2015; Davenport et al. 2016), little is known regarding scavengers in freshwater stream systems. Dominant fully aquatic salamanders are important foragers in these systems and may rival the biomass of predatory fish species (Davic and Welsh 2004). One fully aquatic salamander in Appalachian streams, the eastern hellbender (Cryptobranchus alleganiensis), occurs in NC streams which receive potentially large seasonal influxes of hatchery reared trout (NCWRC 2017). Moreover, few reports exist in the published literature on the food preferences of eastern hellbender salamanders. While hellbender diet is comprised of 90% crayfish based on stomach content analysis (Peterson et al. 1989), a small portion of their diet is thought to include fish or fish bait (Nickerson and Mays 1973). Barring a few anecdotal reports from fisherman, little is known regarding scavenging by hellbenders in NC.