Tuesday, October 16, 2012

Day 9

Longline Lineup

Lionfish Sighting
      aboard the R/V Falkor

The first task for the day was a CTD cast at our deepest site on the cruise. As the CTD descended to 1100 meters (3600 feet), Dr. Wetz and crew collected water for plankton samples and to obtain "pure" water for in-lab filtering. Deploying the equipment and gathering the samples took about an hour just to get down to the bottom of the seafloor. Our next plan was to perform an ROV dive at BA-A-132 and longline sampling at the same location.

Lionfish at site BA-A-132
Ironically this morning an article appeared in a Scientific American blog on how busy we have been on this expedition counting fish. The article referenced the use of longlines, searching for lionfish, and exploring the liberty ships. As the ROV explored BA-A-132 we spotted numerous fish species previously seen, but we also observed a few new species including a soapfish and a blue tang. Visibility at this site was the best yet and the ROV was able to survey the entire structure all the way to the seabed with perfect water clarity.  Toward the end of the dive the sub rounded the edge of the underwater rig near a pipe hole, and inside was another lionfish similar to the fisheries group's previous sighting (see below). The fish's back was turned facing into the structure when first spotted.  These fish are an invasive species introduced into Florida waters and we first documented at the Flower Garden Banks in August 2011. Gradually lionfish are spreading further along the Texas Coast and with few predators and a voracious appetite, they can pose a threat to our natural ecosystems.  Drs. Stunz and Ajemian will continue to monitor the abundance and distribution of lionfish as they monitor the artificial reefs off the Texas coast.

Below is a video taken by Dr. Ajemian and Megan Robillard from their latest survey using their micro ROV in September 2012 at Site MU-A-16 (toppled rig) 40 miles southeast of Port Aransas.

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