Complex patterns of genetic population structure in the mouthbrooding marine catfish, Bagre marinus, in the Gulf of Mexico and U.S. Atlantic

Patterns of genetic variation reflect interactions among microevolutionary forces that vary in strength with changing demography. For marine species, these patterns are often interpreted under the expectation that larval movement drives connectivity because most marine species exhibit broadcast spawning dispersal strategies. Here, patterns of variation within and among samples of the mouth brooding gafftopsail catfish (Bagre marinus, Family Ariidae) captured in the U.S Atlantic and throughout the Gulf of Mexico were analyzed using genomics to generate neutral and non-neutral SNP data sets. Because genomic resources are lacking for ariids, linkage disequilibrium network analysis was used to examine patterns of putatively adaptive variation. Finally, historical demographic parameters were estimated from site frequency spectra. The results show four differentiated groups, corresponding to the (1) U.S. Atlantic, and the (2) northeastern, (3) northwestern, and (4) southern Gulf of Mexico. Pa..., Sampling and library prep
Fin clips were obtained from 382 mixed-age samples of gafftopsail catfish collected from nine geographic sampling locations (hereafter locations; Figure 1) from 2015 to 2018: one in the Atlantic in Indian River Lagoon, Florida and adjacent coastal waters (ATL) and eight in the Gulf. Locations in the Gulf were near Tampa Bay, Florida (FLGS), North of Tampa Bay, Florida (FLGN), near Mobile Bay, Alabama, (MB), in Mississippi Sound, Mississippi (MISS), in Chandeleur Sound, LA (CS), off Louisiana west of the Mississippi River (LA), in Corpus Christi Bay, Texas (CC) and in the Bay of Campeche, Mexico (CAMP). All locations were selected because they represent inshore habitats used by mouth brooding males for parturition and by juveniles as nursery habitat, except CAMP which was opportunistically sampled further offshore. Sampling took place as part of surveys routinely conducted by state or academic entities, the latter following approved animal care protocols. All fi..., , # Complex patterns of genetic population structure in the mouthbrooding marine catfish, Bagre marinus, in the Gulf of Mexico and U.S. Atlantic

[https://doi.org/10.5061/dryad.nvx0k6f0n](https://doi.org/10.5061/dryad.nvx0k6f0n)

The three genepop files consist of a complete dataset as well as the dataset split into neutral and outlier loci. A metadata text file is also included to describe the catch locations of the samples.

## Description of the data and file structure

The complete genepop dataset (BMA_by_pop_genepop.gen) consisted of 367 gafftopsail catfish (Bagre marinus, Family Ariidae) samples genotyped at 5,554 microhaplotype loci (14,682 SNPs) collected from the western North Atlantic Ocean ranging from Indian River Lagoon, Florida to the Bay of Campeche, Mexico. The neutral genepop file (BMA_by_pop_only-neutral_genepop.gen) is a subset of the complete file which contains 5,421 loci while the outlier genepop (BMA_by_pop_all-outl_genepop.gen) contains 133 loci. The sample names f...,