Dataset: Ichthyoplankton density and plankton displacement volume data collected using SEA-GEAR plankton ring nets on the NSF RAPID Plankton Cruises in the Northwestern Gulf of Mexico in 2017-2018

The Ring Plankton Net was deployed using the same procedures reported for the NOAA Bongo Plankton Net in the "NOAA SEAMAP Field Operations Manual for collection of data, Chapter V., National Marine Fisheries Service and Gulf States Marine Fisheries Commission, October 2001, Revision No.4."

Target Fishing Depth as much of the water column as possible stopping 2-4m above the bottom at bottom depths <200m, and upper 200m at bottom depths >200m; ship speed 1.5-2.0 knots; target wire angle of 45°; winch speeds during pay out and retrieving according to Chapter V., Table A. The net was deployed over the side.

Nets were rinsed and processed on board. A subset of larval fish was picked on board and frozen at ultra-low temperatures in liquid nitrogen and kept in an on-board Ultra Low Temperature Freezer, transported using a Dry Shipper to Texas A&M University Corpus Christi and stored in an ULT until further processing. The remainder of the sample was preserved in 200 proof Ethanol (ETOH) according to NOAA SEAMAP Operations Manual upon retrieval of nets. After 24 hours, ETOH was exchanged with fresh ETOH. ETOH Plankton samples were stored in 1000ml plastic jars until processing in the Geist Early Life History Research Laboratory at Texas A&M University Corpus Christi during 2017 and 2020. Total Zooplankton Displacement Volume was determined using a calibrated 1000ml measuring cylinder by subtracting the volume of ethanol without sample from the volume of ethanol with sample. The plankton sample was separated from ethanol using a concentrator sieve with a mesh size < than the net mesh size. Then the plankton sample was resuspended in ETOH and larval fish were picked under dissecting microscopes using feather steel tweezers. Every sample was looked through twice for quality check purposes.