Abstract:
This dataset reports presence/absence and density data for epipelagic tows collected in the northern Gulf of Mexico during R/V Blazing Seven cruises LF2016A and LF2016B (2016-06-09 to 2016-07-28). Larval fishes were sampled from 48 stations and cruise data were collected at each site including latitude/longitude, date, time, environmental data (temperature, salinity, dissolved oxygen) and Sargassum dry weight. Larval catch data before and after the oil spill will be compared to improve our understanding of the causes of temporal variability as it relates to the Deep-Water Horizon oil spill (DWHOS). Habitat associations of selected taxa (billfishes, tunas, dolphinfishes, flyingfishes) will be examined before (2007-2009) and after (2015-2017) the DWHOS, and catch data will be coupled with environmental data to identify critical spawning/nursery habitats of several pelagic fishes in the nGoM. In addition, life history and ecosystem parameters that favor the production and survival of pelagic fish larvae and juveniles from multiple cohorts (2015-2017) will be compared to estimates before and after the DWHOS.
Suggested Citation:
Rooker, Jay R. and R.J. David Wells. 2018. Presence/absence and density data for epipelagic tows collected during R/V Blazing Seven cruises LF2016A and LF2016B, northern Gulf of Mexico from 2016-06-09 to 2016-07-28. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N76M356C
Purpose:
Generalized additive models (GAMs) will be developed for periods before (2007-2009) and after (2015-2017) the DWHOS event to characterize habitat associations of selected taxa (billfishes, tunas, dolphinfishes, flyingfishes). Habitat suitability models will then be 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 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) will be compared to estimates before and after the DWHOS.
Data Parameters and Units:
Cruise (LF2016A and LF2016B), Year, Month, Collection date (MM/DD/YYYY), Station, Sample ID, Net Type (neuston net-NN, bongo net 333-BN3, bongo net 500-BN5, ring net-RN, first net drop at station-1, second net drop at station-2), Start Latitude (DD), Start Longitude (DD), Stop Latitude (DD), Stop Longitude (DD), Central Time (HH:MM), Sea Surface temperature (SST, °C), Salinity, Dissolved Oxygen- DO (mg/L), Sargassum (kg), Tow time (min), Flowmeter (FM) Volume Sampled (m^3), Environmental Comments, Sample ID, Frozen Istiophoridae (count), Istiophoridae Total (count), Frozen Xiphias gladius (count), Total Xiphias gladius (count), Frozen Coryphaenidae (count), Total Coryphaenidae (count), Exocoetidae (count), Frozen Scombridae (count), Total Scombridae (count), Pterois sp. (count), Myctophidae (count), Gonostomatidae (count), Sternoptychidae (count), Frozen Non-target Fish (count), Squid (count), Frozen Invertebrates, Invertebrate Biomass (g)
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. Blanks in “Time column” means data was not collected. Blanks in row 35: this was ring net station; no fluorometers were attached to this nets so there is no associated volume. Blanks in “Total Fish column” should be 0. Larvae were collected with three different gear types: 1) neuston net (2 m width x 1 m height frame) with 1200 micron mesh; 2) paired 61-cm bongo nets with 333 and 500 micron mesh; 3) paired ring net with 1000 micron mesh. Neuston nets were towed through the upper meter of the water column while oblique tows to ca. 100 m were made with the paired bongo nets. Ring net sampling was conducted at night on 2 stations to 500m depth. General Oceanics flow meters (Model 2030R, Miami, FL), were placed within net frames determine the surface area sampled by each net. Fish larvae and early juveniles collected with net gears were preserved onboard in 95% ethanol; a subsample of the catch will be placed on dry ice in the field for subsequent RNA:DNA or stable isotope analysis. Overall fish biomass will be measured in the lab and samples will be initially sorted to 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.
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