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CRES: Component: Fish Coupling Species and Habitat
OVERVIEW
The basic premise of this component is that cross-habitat movements of organisms play a vital role in the structure and function of coral reef systems, that is, fish act as important vectors for the transport of nutrients, organic matter and energy, and that this transport is nonrandom, leading to hotspots of productivity. Secondary premises that derive from this include contentions that: (i) Movement and distribution of organisms are determined by the types, amounts and distribution of different habitats; (ii) Movements of organisms play a vital role in the health of coral reef ecosystems; (ii) Fish diversity and abundance, as well as age-class diversity within fish species, will be maximum where there is maximum habitat diversity; (iii) Deep-water and muddy bottoms are ecological barriers to reef fish movements; and (iv) regional fisheries may benefit from the cross-shelf movements of commercial fish and invertebrates between MPAs and nonMPAs. Coral reef degradation will impact the strength of ecological linkages and how species utilize particular habitats. By the same token, the breakdown of these ecological linkages through overfishing and alteration of community structure, will lead to a decline in coral reef productivity and health.
Habitat Utilization & Energy Transport
OBJECTIVES
- Determine how species' habitat utilization patterns differ at sites with varying states of habitat structure and reef degradation
- Determine how species' habitat utilization patterns differ inside and outside a Marine Protected Area (MPA)
- Examine the role do fish species take in transporting energy between habitats
DESCRIPTION
This work, led by NOAA's National Centers for Coastal Ocean Science (NCCOS), aims to provide an understanding of reef fish habitat utilization patterns and energy transport. By understanding the connection between species and habitat as well as movements between habitats managers will better understand the consequences of a particular management action (e.g., setting up a Marine Protected Area, designating Essential Fish Habitat, evaluating coastal development). To contribute to this understanding NCCOS will employ multiple survey methodologies including underwater visual censuses of the fish community and associated habitat using SCUBA as well as deployment of passive fishing gear.
To evaluate species' habitat utilization patterns, sampling locations are randomly chosen over hard-bottom habitats throughout St. John and southwestern Puerto Rico . This random selection ensures statements made are applicable over the entire region of interest. Additional sites are selected inside and outside the recently created Virgin Islands Coral Reef National Monument , an MPA south of St. John . The hard-bottom regions have been previously delineated and geo-referenced in a series of benthic habitat maps (NOAA 2001) and all site selection is done using ArcView GIS software. Habitat data is analyzed to determine which of a suite of variables best quantifies the state of reef degradation. These variables are then related to metrics of fish community structure to determine how the state of reef health influences fish communities throughout the study region. Data is further explored to determine if patterns of fish habitat utilization differ within and outside of the MPA.
To evaluate the role fish species take in energy transport between habitats, adult and sub-adult fishes are collected at habitat boundaries during migration movements associated with foraging. Sampling locations are again chosen utilizing the habitat maps (NOAA 2001) which are stratified into four habitat boundary classes: seagrass/reef; seagrass/mangrove; seagrass/unconsolidated sediments; and mangrove/unconsolidated sediments; as well as three zones: lagoon; outer lagoon; and bank shelf. Fish movement is inferred by noting fish orientation in the net and gut contents are removed in the laboratory and preserved for identification. Gut contents are identified to the lowest possible taxonomic level and weighed. Results are then evaluated to determine the type and direction of energy transport.
RELATION TO OTHER RESEARCH COMPONENTS
The results of this particular project will be integrated with concurrent studies under the same proposal. Within the ìReef Processesî component of the proposal PIs are working on mark and recapture and acoustic tagging studies. These studies are designed to examine the patterns of movement of adult fish species and evaluate home range size. The energy flow work being conducted by NCCOS will allow interpretation of these movements. Furthermore, by utilizing the habitat utilization information gathered by NCCOS in conjunction with these other studies, proposed MPAs can be evaluated based on the health of their reefs and their size.
Work is also being conducted on the CRES grant to consider socioeconomic factors in the delineation of MPAs and to identify how best to include the public in the delineation process. In combination with the biological analyses this work will aid significantly in the evaluation of proposed MPAs.
All results obtained as part of this study will be made available to other PI's via the Database Management System as well as to other researchers via a website and peer-reviewed publications.
Fish Movements and Habitat Coupling
OBJECTIVES- Determine processes affecting the direction of migration during ontogenetic habitat shifts.
- Determine if ontogenetic habitat shifts occur as an individual or group process.
- Determine the range of daily feeding migrations for fishes known to be important vectors for the transport of organic matter across habitat boundaries.
- Determine the role of habitat in determining the pathway of daily feeding migrations.
- Integrate results of study with information collected on the association of habitat and species/ontogenetic stage distributions collected by NCCOS.
- Integrate results of study with information collected on cut contents of fishes crossing habitat boundary collected by NCCOS and UPR.
DESCRIPTION OF PROJECT
Using data on habitat utilization and published growth rates of fishes, the flow of individuals across the shelf and among habitats will be modeled. However, lack of a basic understanding of how fish orient and move in relation to habitat distributions, current flow, population density gradients, etc. prevents development of robust principles concerning habitat linkages. The University of Puerto Rico - Mayagüez and the University of Rhode Island will undertake mark recapture studies to test hypotheses on the direction of migration with respect to current flow, depth gradient, and habitat orientation and type. This work will target the ontogenetic migrations of discrete schools of juvenile grunts and utilize coded wire tags. Tagging and recapture locations will be chosen so as to isolate potential controlling factors.
Previous work on the cross-habitat transport of organic matter by fish feeding migrations (NCCOS, UPR-M) has determined the primary species involved and amount of material transported. Acoustic tagging of selected species will be conducted by UPR-M to determine the spatial extent of this transport. At the same time, overlaying tracking data on high resolution side scan sonar imagery of the bottom should provide detailed information on the pathways utilized and their relationship to habitat features and distribution.
RELATION TO OTHER RESEARCH COMPONENTS
The results of this particular project will be integrated with concurrent studies within the CRES program. These data will be combined with data NCCOS's project on Habitat Utilization to explain the distribution of organisms within the La Parguera area and the general movement of nutrients and organic matter over the habitat seascape. These, in turn, will identify the important, spatially explicit linkages within the system.
A key component of the CRES program is to evaluate MPA's, specifically Marine Reserves, as a management strategy for coral reef conservation. This work will serve that objective in two ways: the field work for the mark-recapture study will explitictly target potential movements into the proposed Turrumote marine reserve, thus establishing the nature of habitati connectivity for this area. In turn, the area of Turrumote is being used as a test case for the development of a spatially explicit mathematical model of marine reserces, and the information on habitat connections between inside and outside the proposed reserve will be directly utilized within the model.
MILESTONES
Year 1 -3 Sampling
Year 4 Sampling
Completed
2005
CONTACT INFORMATION
Mark E. Monaco, Ph.D.
1305 East-West Highway
SSMC-IV, 9th Floor
Silver Spring, MD 20910
301-713-3028, Ext. 160
mark.monaco@noaa.gov
Technical Contact:
Chris Caldow
1305 East-West Highway
SSMC-IV, N/SCI-1
Silver Spring, MD 20910
301-713-3028, Ext. 164
chris.caldow@noaa.gov
