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2010 BENTHIC & FISH SURVEY CRUISE
Two-toned blue dashed line

May 17-21, 2010
aboard the R/V Manta

The purpose of this expedition was to survey East and West Flower Garden Banks to quantitatively assess the benthic habitat and fish communities.

The expedition was conducted in conjunction with partners from the National Center for Coastal Ocean Science (NCCOS). Harbor Branch Oceanographic Institute (HBOI), and the University of North Carolina-Wilmington (UNCW).

Participants

R/V Manta Crew:

Captain Darrell Walker
Mate Mike Shetler
Mate Dean Henagan
Cook/Deckhand Dennis Cooley

Two men standing at the controls of a winch on the top deck of a boat.
Mike Shetler and Darrell Walker operate the A-frame from the top deck of the R/V Manta. Photo: Schmahl/FGBNMS

Scientific Crew:

Emma Hickerson, FGBNMS
Marissa Nuttall, FGBNMS
G.P. Schmahl, FGBNMS
Lance Horn, NURC/UNCW, ROV Technician
Glenn Taylor, NURC/UNCW, ROV Pilot
John Reed, HBOI
Josh Voss, HBOI
Charlie Menza, NCCOS
Erik Ebert, NCCOS

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Overview

The R/V MANTA departed from the TAMUG dock on the evening of Sunday, May 16th. A smooth ride with flat seas put the ship at East Flower Garden Bank early on the morning of the May 17th.

Flat seas on Monday (5/17) allowed the R/V Manta crew to observe two hammerhead sharks, a manta ray, and two unidentified surface swimming sharks from the back deck. However, seas gradually picked up throughout the week, reaching 3-4 ft (1 m) by Friday morning.

A shark's dorsal fin and the tip of its tail visible on the water's surface.
An unidentified shark swims at the surface near the
R/V Manta. Photo: Schmahl/FGBNMS

Monday and Tuesday were spent running transects on East Flower Garden Bank before the ship moved to West Flower Garden Bank on Wednesday. Two more days were spent running transects at West Flower Garden Bank. Friday morning (5/21) was spent conducting coral reef cap transects at both East and West Flower Garden Banks.

Three people lowering an ROV into the water off the back of a boat.
Launching the ROV from the back of the R/V Manta in
calm seas. Photo: Schmahl/FGBNMS

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Acoustics
Erik Ebert/Chris Taylor, NCCOS-SCCFHR

Approximately 100 nm of East and West Flower Garden Banks were surveyed from the R/V MANTA using a fixed pole and split-beam fisheries sonar system. The survey covered both coral caps on each bank and a variety of habitats over a range of depths to 150 m (492 ft). 

The hydroacoustic data we collected will be used to map the abundance and distribution of fish in the sanctuary and compare these patterns across habitats and over time. Pairing the acoustic survey to the ROV observations will allow a direct comparison to the visual observation of fish communities and habitat data. 

Colored lines of various widths on a black background.
Acoustic representation of fish over East Flower Garden Bank . The thick arced red line in the bottom portion of the image represents the contour of the coral cap. The clusters of light blue dots above the red show the locations of fish.

Post-processing of the hydroacoustic data will take place at the Center for Coastal Fisheries and Habitat Research in Beaufort, NC.  Interesting patterns of fish distribution have already been observed (see below).

Colored lines of various widths on a black background.
Acoustic representation of fish over West Flower Garden Bank . The sloping red line in the bottom portion of the image represents the contour of the coral cap. The clusters of light blue dots above the red show the locations of fish.

These hydroacoustic surveys and ongoing monitoring of the sanctuary will enhance our understanding of changes in fish abundance and distribution over space and time.

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ROV Transects

A total of fifteen 100 m (328 ft) transects were randomly plotted on bathymetric maps at both East and West Flower Garden Banks, in each habitat zone: the Soft Bottom Community, the Deep Coral Zone, the Coralline Algae Zone, and the Algal Nodule Zone.

Three people watching a large screen monitor showing images from the sea floor.
John Reed, Marissa, and Emma sit in the galley of the
R/V Manta to watch a live feed of images from the ROV.
As they watch, they are documenting what they see.
Photo: Schmahl/FGBNMS

In addition, six transects were randomly plotted in the Coral Cap of both East and West Flower Garden Banks. The surveys along the coral cap will be used to compare ROV transects to SCUBA diver surveys.

During May 17-18, seven (7) ROV dives were conducted at East Flower Garden Bank and thirty-six transects completed. Thirteen of  these transects did not match the habitat zone they were within, and were therefore reclassified to the correct habitat zone.

After reclassification, a total of ten (10) transects were completed in the Algal Nodule Zone, six (6)in the Coralline Algae Zone, ten (10) in the Deep Coral Zone, and nine (9) in the Soft Bottom Community.

A man sits in front of a bank of monitors and controls to operate an ROV
Lance Horn pilots the ROV from the dry lab of the R/V Manta. The galley, where others are recording data (see photo above), is located behind this equipment.
Photo: Schmahl/FGBNMS

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During May 19-20, twelve (12) dives were conducted at West Flower Garden Bank and thirty-seven transects were completed. One transect did not match the habitat zone it was within, and was reclassified to the correct habitat zone.

After reclassification, a total of ten (10) transects were completed in the Algal Nodule Zone, fourteen (14) in the Coralline Algae Zone, ten (10) in the Deep Coral Zone, and three (3) in the Soft Bottom Community. A mobulid ray was observed from the ROV at 283ft at West Flower Garden Bank.

Three men pull an ROV back onto the deck of a boat.
The boat's A-frame is used to hoist the ROV back onto the boat after running a transect. Photo: Schmahl/FGBNMS

May 21 was used to complete the coral cap transects at East and West Flower Garden Banks. This required one dive at each bank. Initially, six (6) transects were conducted at West Flower Garden Banks and five (5) were conducted at East Flower Garden Bank. One transect did not match the habitat zone it was within, and was reclassified to the correct habitat zone.

After reclassification, a total of five (5) transects were conducted on the Coral Cap at West Flower Garden Bank, and seven (7) at East Flower Garden Bank. Tunicate growth and a large loggerhead sea turtle were observed from the ROV at East Flower Garden Bank.

A total of 84 transects were conducted:

  • Coral Cap - 12
  • Algal Nodule Zone - 20
  • Coralline Algae Zone - 20
  • Deep Coral Zone - 20
  • Soft Bottom Community - 12

The number of images taken in each transect varied by the speed at which the ROV traveled. The average number of images per transect was 13, with a minimum of 8 and a maximum of 21 images.

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Biological Sampling

A total of five samples were collected using the ROV manipulator arm. Two directed samples were collected, and three opportunistic samples. Samples included black corals (Family: Antipathidae), a yellow gorgonian sea fan, a solitary cup coral, and a collection of small rocks. Samples were stored in ethanol for preservation.

Three people gathered around an ROV to collect a small sample of coral from the manipulator arm.
Marissa provides a tub of water to hold a coral sample
retrieved by the ROV. Photo: Schmahl/FGBNMS

Download the Benthic Survey 2010 Cruise Report (56kb pdf)

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Orange, branching gorgonian (soft coral) anchored in a bed of sponges and other sea life.
   
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