Gray's Reef National Marine Sanctuary
Gray's Reef National Marine Sanctuary
2017 Gray's Reef Research Cruise Photos
Mission Information
 

Gray's Reef Research
Expeditions 2017

Friday: June 16, 2017
Log Day 8

Jody Patterson
Gray's Reef Events & Volunteer Coordinator
Savannah, GA

Peter Auster, UCONN, Mystic Aquarium (L) and Randy Rudd, NOAA Team Ocean Diver (R), give the OK to dive.

Peter Auster, UCONN, Mystic Aquarium (L) and Randy Rudd, NOAA Team Ocean Diver (R), give the OK to dive.
(Photo: Jody Patterson, GRNMS)

Even with 3' seas today, our dive teams set out on the zodiac small boats and were able to survey five sites each. This concentrated effort will have huge payoffs in our long-term understanding of Gray's Reef and the animals that live here. The teams predetermined the sites they wished to visit for surveying fish populations, invertebrate cover and predator-prey interactions then set off to begin work at 0800.

Schools of tomtate and scad.

Schools of tomtate and scad.
(Photo: Peter Auster, UCONN, Mystic Aquarium)

"The ledges were draped in schools of tomtate and scad" according to Dr. Peter Auster whose study seeks to uncover how different fish predator species interact with each other. He and volunteer science diver Randy Rudd descended on a site inside the Gray's Reef research area and returned noting that juvenile barracuda appeared to be hiding inside a school of small tomtate, like young chicken hawks in a hen house. They were eating the tomtate and driving them down to the reef ledge where black sea bass were preying on them as well. "Blue runner were driving bait fish down into the sand and big barracuda were circling high above them in the water column," Rudd noted upon return to the ship.

Randy Rudd photographing reef ledge.

Randy Rudd photographing reef ledge.
(Photo: Peter Auster, UCONN, Mystic Aquarium)

Auster describes an invisible fabric in fish communities that defines the predatory-prey relationship. "We know who eats who, but we don't know how individuals of different species interact together to increase predation rates, how these mixed species hunting groups occur, and at what places these kinds of behaviors are common."

His study includes a cadre of tools that he hopes will help define the distribution of species over space and time. He has his ever-ready dive camera, but he has also deployed a time-lapse camera and a 360° imaging camera for prolonged exposure to collect passive observations when divers are not present.

Time-lapse of shark patrolling reef.

Time-lapse of shark patrolling reef.
(Photo: Fabio Campanella, NOAA-NOS)

"There are more sharks at that site than we thought" Auster remarked when viewing the time-lapse images collected the last couple of days. Sharks are one of the species he refers to as halo predators. These predators patrol from reef to reef, and along with resident predators keeping prey species on their toes, so to speak, staying close to shelter or in large schools for safety. How these animals behave in the absence of humans may be inferred from this type of observation. "Time lapse photography provides these nuances that we don't see when diving" Dr. Auster noted.

360° image of Spanish mackerel over live-bottom.

360° image of Spanish mackerel over live-bottom.
(Photo: Peter Auster, UCONN, Mystic Aquarium)

Determining how fish species act in the presence or absence of other species can shed light on this interrelated fabric of our ocean life. As John Muir articulated as a fundamental ecological principal of connectedness, "When we try to pick out anything by itself, we find it hitched to everything else in the Universe". The tapestry of life woven together at Gray's Reef is a remarkable example of this connected fabric.


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