Abstract:

This dataset contains striped anchovy (Anchoa hepsetus) and sand seatrout (Cynoscion arenarius) growth and condition data collected aboard R/V Point Sur cruise PS16-20 (cruise PTS02) in the northern Gulf of Mexico from 2016-04-08 to 2016-04-10. During a high discharge event from the Mobile Bay plume over April 8-11th, 2016, larval fish samples were collected using a Bedford Institute of Oceanography Net Environmental Sampling System (BIONESS). The BIONESS (0.25 m^2 opening) was fitted with 333-µm and 202-µm mesh nets. Ichthyoplankton samples included in this data set were collected nearshore on the coastal shelf downstream of the Mobile Bay river plume to examine how variable freshwater discharge affects larval fish distributions, growth, and morphometric condition. Within the sampling area, plume water masses were identified by salinity (≤25). The growth and morphometric condition of larval fishes (striped anchovy and sand seatrout) collected from these plume water masses were compared to conspecifics collected from nearby shelf (non-plume; >32 salinity) water masses. The dataset includes the sample collection information (date, gear number, water mass the station was located within, station locations); daily growth, recent growth, and condition data; and raw images of larval striped anchovy and sand seatrout.

Suggested Citation:

Kelia Axler, Su Sponaugle, Frank Hernandez, Carla Culpepper. 2020. Striped anchovy (Anchoa hepsetus) and sand seatrout (Cynoscion arenarius) growth and condition data collected aboard R/V Point Sur cruise PS16-20 (cruise PTS02) in the northern Gulf of Mexico from 2016-04-08 to 2016-04-10. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/M4ZEFDZY

Purpose:

Data were collected during the CONCORDE Spring 2016 cruise to examine how variable freshwater discharge can affect larval fish growth and morphometric condition.

Data Parameters and Units:

The file "PTS02_Anchovy_Seatrout_Plume_Process_Study" includes multiple worksheets with Striped anchovy (Anchoa hepsetus) and sand seatrout (Cynoscion arenarius) growth and condition data. The contents of the worksheets are described below: The worksheet "Station Coordinates": Gear Number (Station ID where sample was taken by a Mininess [MN] or Bedford Institute of Oceanography Net Environmental Sampling System [BIONESS]), Water Mass (Identified water mass the station was located within; Plume versus Nonplume/Shelf), Lat_begin (Latitude at beginning of each station used in ichthyoplankton analyses; decimal degrees), Lon_begin (Longitude at beginning of each station used in ichthyoplankton analyses; decimal degrees), Lat_end (Latitude at end of each station used in ichthyoplankton analyses; decimal degrees), Lon_end (Longitude at end of each station used in ichthyoplankton analyses; decimal degrees). The worksheets "Striped anchovy daily growth" and "Sand seatrout daily growth": Species (Anchoa hepsetus or Cynoscion arenarius), Fish ID (Unique larval fish identifier), Date (M/DD/YYYY), Water Mass (Identified water mass the station was located within; Plume versus Nonplume/Shelf), SL (The standard length of each larva in mm), Age (The age of the individual as counted by daily otolith rings in days), Otolith Radius (The length of the otolith from the center to the edge in µm), DayXX (Daily otolith increment width in µm). The worksheets "Striped anchovy recent growth" and "Sand seatrout recent growth": Fish ID (Unique larval fish identifier), Water Mass (Identified water mass the station was located within; Plume versus Nonplume/Shelf), Mean Recent Growth (The average width of the last three full growth increments in µm), Age (The age of the individual as counted by daily otolith rings in days) The worksheets "Striped anchovy condition" and "Sand seatrout condition": Date (M/DD/YYYY), Water Mass (Identified water mass the station was located within; Plume versus Nonplume/Shelf), Fish ID (Individual larval Gulf Menhaden identifier), MN (Station ID where sample was taken by a Mininess [MN] or Bedford Institute of Oceanography Net Environmental Sampling System [BIONESS]), Net (Net number that sample was taken from), AvgSalinitypsu (The averaged salinity for each net tow; psu) AvgTempC (The averaged temperature for each net tow; degree C), SL (The standard length of each larva in mm), Size Class (The size class of each larva in mm), Eye Diameter (The diameter of the larva's eye in mm), Lower Jaw Length (The length of the larva's lower jaw in mm), Head Depth (The depth of the larva's head in mm), Head Length (The length of the larva's head in mm), Depth at Pectoral Fin (The depth of the body at the larva's pectoral fin in mm), Depth at Anus (The depth of the body at the larva's anus in mm), Depth at Pelvic Fin (The depth of the body at the larva's pelvic fin in mm), Gut Length (The length of the larva's gut), Dorsal Depth (The depth of the larva's dorsal in mm). The file "GRIIDC_Cruise_Data_Documentation_Template_Larval_Growth_Condition" is the cruise documentation with cruise information for the R/V Point Sur cruise led by chief scientists Adam Greer & Alison Deary. The folders "Engraulidae, A. hepsetus" and "Sciaenidae, C. arenarius" includes the raw images (Tiff file) of striped anchovy, A. hepsetus, (Engraulidae) and Sand Seatrout, C. arenarius, (Sciaenidae) respectively. Please note that the image file name is the sample number which can be linked to the morphometric measurements in the spreadsheet.

Methods:

The contents of the plankton net were fixed in 95% ethanol and stored in 85% ethanol after rinsing with seawater and sieving. A Leica MZ9.5 dissecting microscope was used to identify fish larvae from the BIONESS nets to lowest possible taxonomic level. A Leica MZ16 dissecting microscope was used to assess body lengths of larval striped anchovy (Anchoa hepsetus) and sand seatrout (Cynoscion arenarius). Imaging was done with a QImaging digital camera and Image-Pro Premier 9.1 software (Media Cybernetics, Inc., Rockville, Maryland). A single reader examined all otoliths from both species twice blind (without knowledge of previous readings, dates, or fish sizes). If there was a less than 5% difference in reading, one read was chosen randomly for analysis. Otoliths whose readings differed by more than 5% were removed from any further analyses (Sponaugle et al. 2009). Five linear body dimensions (six for seatrout larvae) that have been shown in other species to vary with larval feeding success, and hence are related to body condition (body depth at the pectoral fin, DPF; body depth at the anus, DA; head length, HL; head depth, HD; eye diameter, ED; and in the case of the seatrouts, lower jaw length, LJL) were used to examine differences in larval fish body condition between plume and shelf (non-plume) water masses. For analysis of body condition, only specimens with the full suite of morphometric measurements were used. The residual of each body measurement (e.g., head depth) was computed from its linear correlation with notochord length to standardize and account for size variation among larvae. To standardize and account for size variation among larvae, the residual of each body measurement (e.g., head depth) was computed from its linear correlation with notochord length.

Instruments:

Bedford Institute of Oceanography Net Environmental Sampling System (BIONESS), 0.25 m^2 opening, fitted with 333-µm and 202-µm mesh nets. All imaging was conducted using a QImaging digital camera and Image-Pro Premier 9.1 software (Media Cybernetics, Inc., Rockville, Maryland).

Provenance and Historical References:

Sponaugle, S., Llopiz, J., Havel, L., & Rankin, T. (2009). Spatial variation in larval growth and gut fullness in a coral reef fish. Marine Ecology Progress Series, 383, 239–249. doi:10.3354/meps07988

Individual Files: