Abstract:

This dataset contains Gulf menhaden (Brevoortia patronus) diet, growth, and condition data collected during the R/V Point Sur cruise BCS01 in the northern Gulf of Mexico from 2016-02-10 to 2016-02-12, a month after the opening of the Bonnet Carré Spillway. Subsurface plankton samples were collected using a bongo net system equipped with 333 and 202 µm mesh nets. Dataset also includes temperature, salinity, scattering at 530 nm, and copepod density data. Within the sampling area, three water masses were identified based on temperature, salinity, scattering, and prey field (copepod abundance). Ichthyoplankton (Gulf menhaden, Brevoortia patronus) diet, growth based on examination of otoliths, and condition based on the ratio of measured to predicted dry mass were analyzed for these three water masses.

Suggested Citation:

Frank Hernandez, Angie Hoover. 2020. Gulf menhaden (Brevoortia patronus) diet, growth and condition data collected during the R/V Point Sur cruise BCS01 in the northern Gulf of Mexico from 2016-02-10 to 2016-02-12. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-xc8m-t572

Purpose:

In response to the opening of the Bonnet Carré Spillway, CONCORDE, in collaboration with other GoMRI consortia ECOGIG, ACER, DEEPEND, and CARTHE, organized a response to address the physical and ecological impacts of a large freshwater diversion on regional coastal ecosystems.

Data Parameters and Units:

The data include one Excel spreadsheet with six worksheets. “Read Me” provides details of the contents of the other five worksheets. The worksheet “Station Coordinates” contains water mass name (identified in the study using physical and biological characteristics), station ID, date [M/DD/YYYY], latitude [decimal degrees N], and longitude [decimal degrees W]. The worksheet “Water Mass Factors” contains water mass name, station ID, temperature [degrees C], salinity [ppt], scattering (at 530 nm), and copepod density [individuals/m^3]. The worksheet “Gulf Menhaden Diet” contains water mass name, station ID, FH# (sample ID), fish number (individual ID [XXX]), and diet items (number of prey items, including 10 prey items and the total number found in the individual fish). The worksheet “Gulf Menhaden Growth” contains water mass name, station ID, FH# (sample ID), age (daily otolith rings [days]), radius (otolith length from center to the edge, [µm]), and L3D (average width of last three full growth increments, [µm]). The worksheet “Gulf Menhaden Condition” contains water mass name, station ID, FH# (sample ID), Dry Mass (mass of each larva after 16+ hours dry time, [µg]), Standard Length (length measurement in iSolution lite from an image of the larva [mm]), mean condition factor (ratio of weight to predicted weight for each individual larva). The dataset also includes the cruise documentation for the R/V Point Sur cruise BCS01, led by chief scientist Adam Boyette.

Methods:

Gulf Menhaden larvae were collected in daylight just below the surface with a bongo net system equipped with side-by-side nets. Each net had a 0.5 m diameter opening, with either 202 or 333 µm mesh. The larvae were imaged under a dissecting microscope fitted with a Canon EOS Rebel T3i digital camera. Gulf Menhaden standard lengths were measured using i-Solution Lite imaging software.

Instruments:

Dissecting microscope, Canon EOS Rebel T3i digital camera, Bongo nets. The bongo nets each had a 0.5m diameter opening; each side was fitted with either a 202 or 333 µm mesh net.

Individual Files: