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Current
Projects
View Past Projects
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"Restoring
estuarine landscapes in Alabama coastal waters through creation of
oyster reefs" |
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Funding Agency: National Marine Fisheries Service
PI: Ken Heck
Co-PI:
Sean P. Powers
This project is
designed to examine the potential benefit of restoration of shallow subtidal oyster reefs on adjacent nearshore habitats located at Point
aux Pines and in the vicinity of Alabama Port, by examining whether such
habitats will (1) result in fisheries enhancement; and (2) facilitate
the maintenance and expansion of other biogenic habitats, by addressing
the following four objectives:
1. documenting changes
in the physical setting of study sites resulting from the addition of
oyster reefs.
2. quantifying oyster recruitment and adult density in created nearshore
reefs.
3. quantifying primary and secondary producers within subtidal and
intertidal habitats between created oyster reef and shoreline.
4. quantifying juvenile and adult fish and mobile invertebrate
utilization of created oyster reefs and adjacent habitats.
Project status:
Reefs were created in Summer and Fall 2007 and field work is ongoing. |
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"Estimating the relative importance of northern Gulf nursery habitats to
adult fish populations: studies of gray snapper (Lutjanus
griseus) and gag grouper (Mycteroperca microlepis)" |
Funding Agency: National Marine Fisheries Service
PI: Ken Heck
Co-PIs:
Sean P. Powers and F. Joel Fodrie
Halting the decline or facilitating the restoration of nearshore
habitats will require an improved method of prioritizing where to spend
limited time, money, and effort. One problem in setting priorities,
however, is that the concept of nursery habitat has rarely been defined
clearly, even in research studies that purport to test it. Most studies
of the nursery-role concept have focused on seagrasses or wetlands and
examined the effects of these habitats on one of three factors: the
density, survival, or growth of juveniles. Generally, an area has been
called a nursery if a juvenile fish or invertebrate species occurs at
higher densities, avoids predation more successfully, or grows faster
there than in other habitats. There are very few studies on movement
patterns of individuals from potential nurseries to adult habitats, and
this is a vital missing link in our understanding of nurseries. Movement
of individuals is one of the most difficult variables to measure in
ecology. Fortunately, vast improvements in technology -- archival data
loggers, stable isotopes, genetic markers, and otolith microchemistry --
now enable researchers to track and infer movements.
Using two species of commercial/recreational
significance, we will attempt to elucidate habitat connectivity of
relevance to Alabama coastal fisheries by:
1. Quantifing the abundances and growth rates of juvenile gray snapper
and gag found in nearshore seagrass meadows of the northcentral Gulf of
Mexico. This will be accomplished by trawling to measure local
abundances in seagrass meadows, and analyzing otolith growth bands to
estimate growth rates.
2. Using the saggital otoliths of juvenile gray snapper and gag
collected in 2006 and 2007, analyzed via Laser Ablation Inductively
Coupled Plasma Mass Spectroscopy (LA ICPMS), to create a “reference
library” of characteristic trace element signals for potential nursery
seagrass beds.
3. For 1- and 2-year-old individuals collected during 2007-2009, sample
the rings deposited during the first year of the fish’s life that can be
compared to the signals from 2006-2007 juveniles to infer the nursery
habitat origin of each individual fish.
4. Coalesce data to determine the nursery “value” of seagrass beds in
the northern Gulf in terms of contribution to overall fishery production
for these species.
Project status: Field work is
ongoing. |
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"Robinson
Island Restoration and Protection" |
Funding Agency: Gulf of Mexico Foundation
PI: Ken Heck
Co-PI: John DindoProject status:
Field work ended in August 2007. Sample and data analysis is still
ongoing. |
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"Ecosystem
Services Provided by Oyster Reefs: An Experimental Assessment" |
Funding Agency: National Marine Fisheries Service
PI: Ken Heck
Co-PI's: Just Cebrian,
Sean P. Powers
Oyster reefs
provide numerous important ecosystem services that are only now
becoming well documented. Through their filtration activities,
oysters remove sediments, phytoplankton, and detrital particles,
thereby reducing turbidity and improving water quality. Thus,
oysters and other suspension-feeding bivalves may counteract impacts
of estuarine eutrophication. Through their removal of organic
particles in the water column, oysters divert energy to benthic food
chains and depress pelagic energy flows that may lead to noxious sea
nettles. Oyster reefs also serve as important
biogenic habitat for benthic invertebrates as well as fishes and
mobile crustaceans. This recognition of oyster reefs as
providers of important ecosystem services, rather than merely a
commodity to exploit, coupled with the dramatic depletion of oyster
reefs in many estuaries of the southeast US has prompted increased
efforts to restore and/or enhance oyster reefs in many estuarine
systems.
This project investigates and quantifies the
potential of oyster reefs to positively change water clarity,
benthic primary production and secondary production, and the nursery
value of marsh creeks around Dauphin Island and Little
Dauphin Island. By employing a Before-After-Control-Impact
Paired (BACI-P) design beginning in the Summer
of 2004,
we have begun to specifically address each point in the overall
hypothesis.
1. quantify and monitor the abundance of water-column
suspended solids, and nutrients imported into and exported out of
the marsh creeks,
2. quantify and monitor the abundance and productivity of
phytoplankton, benthic micro- and macroalgae, and macrobenthos,
3. quantify and monitor species number, densities and
secondary productivities of infaunal and benthic macrofaunal
communities,
4. quantify and monitor relative abundances of juvenile and
adult fish and mobile invertebrates.
Ultimately, the results of our study will assist in providing the
conceptual and empirical basis to make realistic predictions of
ecosystem benefits resulting from oyster reef restoration.
Project status: Field
work ended in August 2006.
Publications: Geraldi, N. R., S. P. Powers, K. L. Heck, Jr. and J. Cebrian. (In
review). Can habitat restoration be functionally redundant for fish?
Response of transient fish and crustaceans to oyster reef restoration in
tidal creeks. Marine Ecology Progress Series. |
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"Quantifying
fisheries benefits of oyster reef restoration in Mobile Bay" |
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Funding Agency: National Marine Fisheries Service
PI: Sean P. Powers
Co-PI's: Ken Heck
A key expectation of many
habitat restoration programs is that creation of additional habitat
will lead to enhancement of local fisheries. In this project,
we examine this expectation for oyster reefs constructed in Mobile
Bay as part of the University of South Alabama's Alabama Oyster Reef
Restoration Program. Specifically, for reefs created in Winter
of 2003/2004 within Mobile Bay we will:
1. quantify oyster spat recruitment, oyster survival and growth,
2. quantify recruitment of oyster-reef resident fishes and mobile
crustaceans,
3. assess the use of restored oyster reefs by non-resident fishes
(i.e., transients and facultative residents).
Project status: Field work ended in November 2005. |
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