Gray's Reef National Marine Sanctuary
Gray's Reef National Marine Sanctuary
Gray's Reef Expedition 2013
Mission Information

Mission Introduction

Scientists, staff and volunteers will conduct a research mission within Gray's Reef National Marine Sanctuary, located 16 miles off the coast of Sapelo Island, Georgia, aboard the NOAA Ship Nancy Foster beginning June 2nd through June 15th. Please join us as we report on the activities and findings of this exciting mission!

Scientists aboard the Nancy Foster will be concentrating on five research projects:
   1) Acoustic Fishery Survey
   2) Fish Censuses
   3) Invertebrate Density and Abundance
   4) Monitoring of Ecological Conditions
   5) Multibeam Mapping

Simultaneously a sixth project, Piscivore Ecology, will be occurring with scientists aboard the Gray's Reef R/V Joe Ferguson.

Black seabass on sparsley colonized livebottom

Black seabass on sparsley colonized livebottom
(Photo: Greg McFall, GRNMS)

We will be posting daily mission logs on the website. So please visit regularly and click on each day's mission log to track progress and experiences.

You can also follow the NOAA Ship Nancy Foster's route on NOAA Ship Tracker.

The primary objective of the cruise is to collect information to better understand, manage, and protect Gray's Reef National Marine Sanctuary.

The five research projects will be conducted by scientists at various times during the expedition, as work on the ship goes on around the clock. For more information on the personnel aboard the NOAA Ship Nancy Foster, please visit our Expedition Team Page.

Transducer mounted on the hull of the ship while in drydock

Transducers mounted on the hull of the ship while in drydock.
Click here for larger view
(Photo: Laura Kracker)

Acoustic Fishery Survey
The NOAA Ship Nancy Foster is equipped with fisheries echosounders - basically fancy fish finders - mounted to the hull of the ship to allow us to quickly map the distribution of fish over a large area. These surveys use the properties of sound in water to help us explore and map fish and other organisms in the entire water column. This information can be used to answer questions such as where do fish like to hang out and how abundant are they?

Fish Censuses
In late 2011, NOAA established a research area in Gray's Reef to increase the opportunity to scientifically discriminate between natural ecological changes with the sanctuary versus changes caused by humans.

One goal of the proposed research area is to determine the effect of bottom fishing on benthic (associated with the ocean bottom) fish populations. Therefore, this year from the NOAA Ship Nancy Foster, we plan to continue the baseline data collection begun on last year's expedition by conducting benthic habitat and fish community surveys at numerous sites located within and outside the research area. As the research area has been in place for less than six months, we do not expect to see any differences; however the surveys will confirm our expectations. At each site, we will measure ledge characteristics such as ledge height and determine the benthic habitat community (sponges, sea squirts, sea urchins, algae) present with a series of stationary photoquadrats.

Feather duster worm

Feather duster worm
(Photo: Greg McFall, GRNMS)

Invertebrate Density and Abundance
Dr. Danny Gleason and students from Georgia Southern University will focus on the ecology of benthic marine invertebrates, such as sponges and corals. Their goal is to gain an understanding of the roles that biotic (e.g., competition, predation) and abiotic (e.g., temperature, sedimentation, current speed) factors play in shaping the community of benthic invertebrates that occur at Gray's Reef. Obtaining knowledge such as this is critical for implementing appropriate management strategies because these benthic invertebrates provide critical resources that support the vast array of fishes that inhabit these offshore reefs.

Conceptual View Of Benthic Fauna At GRNMS: Click image for larger view

Conceptual view of benthic fauna at GRNMS

Monitoring of Ecological Conditions
During the Gray's Reef cruise aboard NOAA Ship Nancy Foster, scientists will be collecting samples as part of a long-term monitoring effort to assess status of ecological condition and potential stressor impacts within the sanctuary with a focus on the soft-bottom benthos and sediment quality.

This work is a follow-up to previous (2000, 2005) ecological characterization of the condition of benthic fauna and concentrations of chemical contaminants in sediments and biota at the Grays Reef National Marine Sanctuary (GRNMS). Results of these earlier studies (Hyland et al. 2001, 2006; Balthis et al. 2007) suggest that the sanctuary was in "good health" with respect to these properties although trace concentrations of pesticides, PCBs, and PAHs were detected in both sediments and biota (albeit at low concentrations).

NOAA Ship Nancy Foster

NOAA Ship Nancy Foster in Gray's Reef
(Photo: Randy Rudd)

Multibeam Mapping
The seafloor of Gray's Reef National Marine Sanctuary was mapped in 2001, using both multibeam and side scanning sonar. Scientists produced a habitat map of the sanctuary's seafloor from that data. The map characterized the sanctuary into four habitat types: densely colonized livebottom, sparsely colonized livebottom, rippled sand and flat sand. The densely colonized ledges and outcroppings comprise only about one percent of all available habitat where fish are known to aggregate. Gray's Reef will be remapped during this year's expedition to provide scientists with information about how the sanctuary habitat has changed during the last ten years.

Piscivore Ecology
The behavioral ecology of piscivores (fish-eating fish) is being studied at Gray's Reef to better understand the interactions that link predators and prey in the sanctuary.


(Photo: Greg McFall, GRNMS)

The project this year expands on these initial observations and combines several methods of observing fish behavior and distribution to get an improved picture of the interactions between species. The primary goal of this work is to determine the importance that these types of behavioral interactions have in local food webs. Beyond basic ecological interests, the results of this work have important implications for managing marine protected areas. Dr. Peter Auster's group and Dr. Laura Kracker from NOAA's NCCOS in Charleston, SC, will collaborate at sea taking an interdisciplinary approach to the question, using both direct underwater observation and hydro-acoustic techniques to observe fishes at multiple space and time scales.


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