Dataset Submitted

SHELF Ichthyoplankton

Authors: Ernst Peebles, Jeremy Browning
Identified On: Jan 17 2019 20:50 UTC
DOI: https://doi.org/10.7266/n7-gyg9-yz64
UDI: F2.x836.000:0004
Project Information

Funded By:
Florida RESTORE Act Centers of Excellence Program

Funding Cycle:
FLRACEP 2

Research Group:
Spawning Habitat and Early-life Linkages to Fisheries (SHELF)

Point of Contact

Ernst B. Peebles
University of South Florida / College of Marine Science
epeebles@usf.edu

Data Collection Period
2017-07-13
to
2017-07-14
Theme keywords

ichthyoplankton

Abstract:

After 2000 EDT h on July 11, 2017, six commercial vessels and two FIO vessels The first station was sampled at 0600 h EDT, after which all vessels moved to their second stations to collect their second drifting-egg samples at 1200 h EDT. At each station, two types of plankton net tows were conducted: (1) a single, horizontal tow that was intended to collect eggs for proportional species-composition determination via DNA barcoding, and (2) three replicate vertical tows that were intended for estimating the number of eggs under 1.0 m-2 of water surface. The horizontal tow consisted of a single, 15-min tow at idle speed using a 335 μm mesh, 1-meter mouth, conical, flowmeter-equipped plankton net. The net ring was equipped with flotation that ensured that the net fished at the surface. The net was towed using braided nylon line attached to the rear gunnel of the vessel, such that the net fished near the vessel, but ahead of the prop wash. Vertical tows had the same gear specifications except for not having flotation at the mouth ring, and instead having a 0.9 kg (2 lb.) weight hanging by paracord from the cod-end hose clamp; adding and removing the flotation and weight were facilitated by carabiners. The vertical net was lowered by hand, cod-end-first, to 30 m depth (or the bottom, if that was reached first) using a pre-marked braided nylon line and then retrieved vertically. After net retrieval, the flowmeter reading (horizontal tows only) and time of day were recorded, and the net was rinsed using the vessel’s wash-down system. Samples were labelled and preserved in 70% isopropanol in ambient seawater. Upon return to the lab, fish eggs within the plankton-net samples were counted and removed using stereomicroscopes at 7-90X magnification. DNA barcoding was based on the region of the cytochrome c oxidase 1 gene (COI), which was amplified and sequenced using established methods. Up to 150 drifting eggs were barcoded from each station. If the total number of eggs in the sample exceeded the number barcoded, the remainder were prorated according to species proportions in the barcoded sample. Egg abundances are reported as density (e.g., number of eggs under one square meter of sea surface).

Suggested Citation:

Ernst Peebles, Jeremy Browning. SHELF Ichthyoplankton. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-gyg9-yz64

Purpose:

Egg densities were measured primarily to estimate spawning biomass of reef fish using the daily egg production method.

Data Parameters and Units:

For each plankton tow, we will assign a unique alpha-numeric identifier code and record the date, start time of day, start latitude and longitude (decimal degrees), depth, tow duration (minutes), volume sampled (m3 from flowmeter or calculated from known fishing depth of vertical tows), total egg density (eggs m-3 for horizontal tows) or the number of eggs below 1.0 m2 of sea surface (vertical tows), number of eggs barcoded (ranging from 1-100), scientific name (or highest possible taxonomic level possible), number of eggs per identified species, and extrapolated egg density per species