Abstract:

This dataset contains sampling and identification of larval fishes from epipelagic tows, and environmental data (temperature, salinity, dissolved oxygen) from 47 stations collected aboard R/V Pelican cruise PE18-01 (LF2017A) in the northern Gulf of Mexico from 2017-07-01 to 2017-07-04. Larvae were collected with paired 61-cm bongo nets with 333 and 500-micron mesh. Oblique tows to ca. 100 m were made with the paired bongo nets. General Oceanics flow meters (Model 2030R, Miami, FL), were placed within net frames to determine the surface area sampled by each net. Fish larvae and early juveniles collected with net gear were preserved onboard in 95% ethanol; a subsample of the catch was placed on dry ice in the field for subsequent RNA:DNA analysis. Overall fish biomass was measured in the laboratory and samples were initially sorted to lowest possible taxonomic level using a Leica MZ stereomicroscope. A multiplex polymerase chain reaction (PCR) was performed with specific primers, PCR products were examined using 1% agarose gels containing ethidium bromide, and identification was made using gel banding patterns. The dataset also includes the location (longitude and latitude) and dates of sample collection.

Suggested Citation:

Rooker, Jay R. and R.J. David Wells. 2020. Presence/absence and density data for epipelagic tows from 47 stations collected aboard R/V Pelican cruise PE18-01 (LF2017A) in the northern Gulf of Mexico from 2017-07-01 to 2017-07-04. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-zs50-v228

Purpose:

Generalized additive models (GAMs) were developed for periods before (2007-2009) and after (2015-2017) the Deep Water Horizon oil spill (DWHOS) event to characterize habitat associations of selected taxa (billfishes, tunas, dolphinfishes, flyingfishes). Habitat suitability models were used to predict the probability of occurrence of each taxa during (2010) and several years after (2011-2013) in relation to regions exposed to oil to identify areas of a high-quality habitat that overlap with regions exposed to the DWHOS. In addition, life history and ecosystem parameters that favor the production and survival of pelagic fish larvae and juveniles from multiple cohorts (2015-2017) were compared to estimates before and after the DWHOS.

Data Parameters and Units:

Cruise (2017A), Year (2017), Month (July), Collection date (M/D/YYYY), Station, Sample ID, Net Type, Start Lat. (Start Latitude in decimal degrees), Start Long. (Start Longitude in decimal degrees), Stop Lat. (End Latitude in decimal degrees), Stop Long. (End Longitude in decimal degrees), Time (24:00), SST (Sea Surface Temperature, degree C), Salinity, DO (Dissolved Oxygen, mg/L), Sargassum (Kg), Tow time (min), Sample ID, Istiophoridae, Xiphias gladius, Coryphaenidae, Exocoetidae, Scombridae, Pterois sp., Myctophidae, Gonostomatidae, Sternoptychidae, Total Fish, Invert Biomass (g). The dataset also includes the cruise documentation for the R/V Pelican cruise PE18-01 (LF2017A). Please note - blank spaces indicate that data were not collected.

Methods:

Sea surface water samples were collected at each station and measured for temperature, salinity, and dissolved oxygen. GPS location was recorded at each station. Larvae were collected with paired 61-cm bongo nets with 333 and 500-micron mesh. Oblique tows to ca. 100 m were made with the paired bongo nets. General Oceanics flow meters (Model 2030R, Miami, FL), were placed within net frames to determine the surface area sampled by each net. Fish larvae and early juveniles collected with net gear were preserved onboard in 95% ethanol; a subsample of the catch was placed on dry ice in the field for subsequent RNA:DNA analysis. Overall fish biomass was measured in the lab and samples were initially sorted to the lowest possible taxonomic level using a Leica MZ stereomicroscope. Larvae were identified to the species level using genetic markers. For all genetic assays, a single eyeball will be removed from each larva and DNA will be extracted using a QIAGEN DNeasy blood and tissue kit (QIAGEN # 69506, Valencia, CA). A multiplex polymerase chain reaction (PCR) will be performed using an Eppendorf mastercycler gradient, QIAGEN Hot Star Taq DNA Polymerase (QIAGEN # 203203), and PCR grade dNTP mix (QIAGEN # 201901). For billfishes, a universal billfish primer set and species-specific primers for sailfish, white marlin, and blue marlin will be used (Simms et al., 2010). Species-specific primers have also been developed in our laboratories for tunas, flyingfishes, and dolphinfishes. PCR reactions will be examined via gel electrophoresis using 1% agarose gels containing ethidium bromide, with species identification based on gel banding patterns.

Instruments:

EXO2 Multiparameter Sonde (Salinity, Dissolved Oxygen, Sea Surface Temperature); Garmin GPSmap76 (Latitude and Longitude); General Oceanic’s flow meters Model 2030R (determine surface area sampled by each net); Leica MZ stereomicroscope; QIAGEN DNeasy blood and tissue kit # 69506; Eppendorf mastercycler; QIAGEN Hot Star Taq DNA Polymerase # 203203; PCR grade dNTP mix QIAGEN # 201901

Provenance and Historical References:

Simms, J. R., Rooker, J. R., Holt, S. A., Holt, G. J., & Bangma, J. (2010). Distribution, growth, and mortality of sailfish (Istiophorus platypterus) larvae in the northern Gulf of Mexico. Fishery Bulletin, 108(4), 478-490.

Individual Files: