Wednesday, June 15, 2016

Return to the Virgin Islands

While Legs 1 and 2 of NF1602 involved updated collection strategies, adaptive sampling, new techniques, and historic port stops, Leg 3 brings us back to some welcome familiar territory, the U.S. and British Virgin Islands! The partners at AOML/PHOD and NMFS/SEFSC have sampled these regions from 2007-2011, and again in 2015

Brewers Bay, St. Thomas, USVI

A plankton sample is preserved
This year, the research collaboration will focus on surveying the oceanographic conditions (using CTD, ADCP, and drifter data), larval reef fish populations (with neuston and MOCNESS net tows), and zooplankton concentrations (mini-bongo) across the coastal shelf of the U.S. Virgin Islands and the surrounding region. Data collected will help us understand the connectivity and variation in the transport and supply of reef fish larvae between managed and non-managed areas in the Virgin Islands. 

Scientist Kathryn sorts a fresh sample
We'll be sorting our plankton samples live on board, like on Legs 1 and 2. This way, we can get real-time information on fish species of interest, and freeze samples immediately so we can conduct DNA and isotope analyses on the samples. Nitrogen isotopes in these samples provide definitive biological linkages and trophic structure comparisons between fish populations. We are especially targeting larval parrotfish. These colorful species are fished locally, especially in St. Croix, USVI. From an ecosystem standpoint, herbivorous parrotfish are valuable grazers on coral reefs, feeding on competitive algae which can inhibit coral recruitment.
The two genera of parrotfish larvae we are interested in: left, Sparisoma sp., and right, Scarus sp.
We have many new faces on board this leg, so stayed tuned for some spotlights on our guest scientists and their research! For now, here's a sneak peak at what we've been up to so far...

Scientists Adrianne, Kathryn, and LaTreese rinse down the "S25" neuston net
Scientist Dan takes light measurements for his optics study
Oceanographer Ryan takes water samples from the CTD
Scientist Mara preserves a microzooplankton sample from the mini-bongo

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