Abstract:

Stomach content analysis was performed on six abundant, yet understudied, species of estuarine/coastal predators: Atlantic Stingray (Hypanus sabinus), Crevalle Jack (Caranx hippos), Gafftopsail Catfish (Bagre marinus), Hardhead Catfish (Ariopsis felis), Skipjack Herring (Alosa chrysochloris), and Smooth Butterfly Ray (Gymnura lessae). Specimens were caught through both fishery-dependent and -independent sampling, with the majority of individuals collected in either Mobile Bay or Mississippi Sound, or within a few miles of the Alabama coast. In total, 3,072 stomachs were removed and examined for stomach content analysis and more than 5,467 individual prey items, comprising 75 different species, were identified. Smooth Butterfly Ray, Skipjack Herring, and Crevalle Jack were highly piscivorous, with fish prey contributing to 100%, 99%, and 93% of their diets by weight, respectively. Gafftopsail Catfish were also fairly piscivorous, with 68% of their diet by weight consisting of fishes. Hardhead Catfish and Atlantic Stingray were generally non-piscivorous, with the majority of their prey comprised of invertebrates. Atlantic Croaker (Micropogonias undulatus) were by far the most prevalent prey item found across species, representing 29% and 54% of all prey by number and by weight, respectively.

Suggested Citation:

Jargowsky, Matthew and Marcus Drymon. 2021. Stomach content data for six common coastal predators from the northern Gulf of Mexico, 2015-05-08 to 2019-09-21. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/DGJNHR98

Purpose:

The purpose of this project was to identify the dietary habits of common, but understudied, coastal predators in the northern Gulf of Mexico.

Data Parameters and Units:

Fish_id-species-family-order-class; Species; SL; FL; NTL; STL_DW; Weight (kg); Sex; Maturity; Location code; Latitude; Longitude (decimal degrees); Date_Caught; Date_Sampled; Notes. Latitude and longitude are estimated and not exact catch locations. Most catch location information was obtained by asking anglers where they caught fish. Predator length in millimeters, predator weight in kilograms, prey weight in grams.

Methods:

Shortly after collection, to prevent the degradation of prey DNA, stomachs were excised from each fish and then stored in either 100% ethanol or frozen at −29°C. These stomachs were later dissected using instruments sterilized with bleach to prevent DNA cross-contamination between stomachs, and prey contents were identified to the lowest possible taxon. These prey items were then blotted dry, quantified, and weighed to the nearest 0.01 g. All free otoliths in the stomach that were not associated with an intact prey item were also counted and identified to the lowest possible taxon using an inhouse reference set and various otolith identification resources (these data can be found in the notes section). All prey items that could not be identified to the species level, including both vertebrate and invertebrate prey, were stored in 100% ethanol for future genetic analysis. All DNA extraction from muscle samples, polymerase chain reaction (PCR) amplification, post-PCR processing and pooling, and bioinformatics were performed at the Genomics Core Laboratory at Texas A&M University-Corpus Christi. A metagenetics approach was used for species identification to help with the identification of highly digested prey materials. Specifically, a 313 bp section of the coI locus was sequenced via paired-end reads at the New York University School of Medicine's Genome Technology Center on an Illumina MiSeq (www.illumina.com). The primers used in PCR amplification were the universal metazoan primers MlcoIint-F and Jghc-02198. Additionally, blocking primers were used to decrease the amplification of predator DNA; however, these blocking primers were omitted for prey items where cannibalism may have occurred. Following bioinformatic processing, each prey item was assigned a single, final OTU, with all prey items that were discriminated at the species level having a >98% sequence match with a species in the reference libraries.

Individual Files: