Abstract:

This dataset includes water temperature, salinity and dissolved oxygen, catch per unit effort (CPUE) data, gut content data, and bulk muscle tissue carbon (delta-13C), nitrogen (delta-15N) and sulfur (delta-34S) stable isotope values of adult spotted seatrout (Cynoscion nebulosus) collected from three (oligohaline, mesohaline, and polyhaline) sites within Barataria Bay, Louisiana from 2003-05-20 to 2004-05-18. Water parameters were measured at ~30 cm below the water surface with a YSI model 85. Spotted seatrout were captured with 46.5 m x 2.5 m or 46.5 m x 1.25 m experimental gill nets. Gut contents were stored in 10% formalin and identified to the lowest possible taxonomic designation. White muscle tissues were analyzed for stable isotope values at Louisiana State University.

Suggested Citation:

MacRae, Pamela S.D., Micah Russell, James H. Cowan Jr., Brian Fry, Sydney Moyo, and Michael J. Polito. 2024. Water parameters, catch per unit effort (CPUE), gut contents, and carbon, nitrogen, and sulfur stable isotope values of spotted seatrout (Cynoscion nebulosus) from Barataria Bay, Louisiana, 2003-05-20 to 2004-05-18. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/jcdnhpf6

Purpose:

This dataset was developed to investigate the relative abundance, diets, and isotopic niches of spotted seatrout (Cynoscion nebulosus) across varying salinity regimes within Barataria Bay, Louisiana.

Data Parameters and Units:

All worksheets contain the same first five variables, in the same column order: Cruise_ID (user defined code for each data collection trip), Site_code (user defined code for each data collection site), Site_name (name of data collection site), Latitude (latitude of sampled sites in decimal degrees), Longitude (longitude of sampled sites in decimal degrees), Year (year of data collection), Date (date of data collection). The “Water” worksheet also contains the variables: Temperature_C (water temperature in degrees Celsius), Salinity_ppt (water salinity in part per thousand), DO_mg_L (water dissolved oxygen in milligrams per liter). The “CPUE” worksheet also includes the variables: Habitat (the benthic habitat type where net sampling took place), Time_h (the duration in hours that gill nets were fished), Trout_count ( the number of spotted seatrout captured), CPUE (the calculated catch per unit effort), and Notes (additional sampling notes).The “Seatrout” worksheet also includes the variables: Habitat (the benthic habitat type where net sampling took place), Common_name (the common name of fish sampled), Scientific_name (the scientific name of the fish sampled), Fish_no (a unique user defined code for each fish sampled), Sample_ID (a unique user defined code for each sample analyzed), Sex (biological sex of fish, if known), Standard_length_mm (fish standard length in millimeters), Total_length_mm (fish total length in millimeters), Mass_g (fish body mass in grams), Gut (notation if fish gut was empty or full), Isotope_tissue (tissue sampled for isotopic analysis), d13C (stable carbon isotope values in per mil units), d13C_norm (stable carbon isotope values in per mil units following normalization for lipid content), d15N (stable nitrogen isotope values in per mil units), d34S (stable sulfur isotope values in per mil units), CN_ratio (carbon to nitrogen elemental ratio), and Notes (additional sampling notes). The following 13 variables in the “Seatrout” worksheet provide the percentage by dry mass of different prey groups found within gut samples: Fish_unidentified, Bay_anchovy, Threadfin_shad, Gulf_menhaden, Atlantic_croaker, Penaeid_shrimp, Fiddler_crab, Amphipods, Polychaetes,, Gastriopod_Neritidae, Plant_material, Detritus, Unidentified_material. In all worksheets NA implied that the data was not collected and/or the variable is not applicable.

Methods:

Spotted seatrout were collected in Barataria Bay, Louisiana from 2003-05-20 to 2004-05-18 using gill nets and Catch per Unit Effort (CPUE) was calculated as the number of fish caught per hour. Water temperature, dissolved oxygen and salinity were also collected on each sampling trip using a YSI model 85. Gut contents were sorted, identified to the lowest possible taxonomic designation, dried at 70° and weighed. A small piece of white muscle tissue was collected, dried, and homogenized in preparation for stable isotope analysis. delta-13C values were normalized for lipid content using the Post et al (2007) equation: delta-13C(normalized)= delta-13C(untreated)-3.32*1.9*CN_ratio.

Instruments:

Carbon (delta-13C), nitrogen (delta-15N), and sulfur (delta-34S) stable isotope values were analyzed at Louisiana State University (LSU), Baton Rouge, Louisiana, using a using a Carlo Erba NA 1500 elemental analyzer coupled with a dual-column GC + O2 scrubber system and Finnigan MAT DeltaPlus continuous-flow stable isotope mass spectrometer. For complete details on stable isotope procedures see Fry (2007).

Error Analysis:

The analytical precision for stable isotopes, based on standard deviations of repeated reference materials were ±0.08, ±0.06, and ±0.15‰, respectively, for delta-13C, delta-15N, and delta-34, respectively.

Provenance and Historical References:

Fry, B. (2007). Coupled N, C and S stable isotope measurements using a dual‐column gas chromatography system. Rapid Communications in Mass Spectrometry, 21(5), 750-756. https://doi.org/10.1002/rcm.2892 Post, D. M., Layman, C. A., Arrington, D. A., Takimoto, G., Quattrochi, J., & Montana, C. G. (2007). Getting to the fat of the matter: models, methods and assumptions for dealing with lipids in stable isotope analyses. Oecologia, 152, 179-189. https://doi.org/10.1007/s00442-006-0630-x

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