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Scaling Up: Linking FAD-associated Local Behavior of Tuna to Regional Scale Movements and Distributions

See also Instrumented Buoys as Autonomous Observatories of Pelagic Ecosystems.
See also Trophic Ecology and Structure-Associated Aggregation Behavior in Bigeye and Yellowfin Tuna in Hawaiian Waters

Progress Reports (PDF): FY 2010, FY 2009, FY 2008, FY 2007

Background and Rationale
The following project addresses several specific research priorities recently identified by the PFRP in its 2005 Research Priorities Workshop Report and related Request for Proposals. The overarching PFRP priority addressed here is the need to understand the pelagic ecosystem on a variety of scales and to determine the functional sizes of pelagic ecosystem units as they pertain to tuna and similar species Within this overall area of emphasis, this project addresses several explicit PFRP priorities including:

  • Studying movements to define functional sizes of ecosystem units (PFRP Workshop Report section 5.2)
  • Using tagging programs to provide information on movement at different scales (section 7.2.1)
  • Determining the effects of FADs on local and wider scale ecosystems and on pelagic fish production (section 5.2)
  • Supporting new tagging techniques and technologies (section 7.2.1).

Most studies of pelagic fish behavior and dispersal are limited logistically to a few localized sites of interest such as seamounts and FADS or to islands where researchers have the best chance of releasing large numbers of tagged animals. Acoustic tagging experiments can yield highly precise data about very localized movements (for instance around FADs), and standard tag-and recapture data can give 'course-grained' indication of longer term dispersal but produce no behavioral data to assist in interpretation of the results. However, as was expressed in the 2005 PFRP scoping workshop, there is now a pressing need to know more about how pelagic fish populations are linked across a range of spatial and temporal scales and about the behaviors that link these different scales. Embedded within this general theme of understanding the functional sizes of ecosystem units, there are specific topics that need to be addressed. These include knowing if local-scale behaviors reflect or predict larger scale movement patterns and, within this topic, what role do arrays of FADs play in the larger scale, longer-term behavior of tunas? How accurately does the sub-set of fishes found around FADs reflect the status and behavior of the regional population? Can FAD-associated abundances be used as a proxy for assessing the status of regional populations? Elucidating the influence of FADs on tuna behavior is a specific regional PFRP priority but this phenomenon is also of global importance in terms of fisheries management and stock assessment. Results acquired in the proposed research could be integrated with larger-scale tag-and-recapture experiments proposed for the western and central Pacific.

Therefore, it is important to extend the geographical range and duration of observations of the movements of tunas that at some point in their lives associate with FADs. By so doing, we will not only get a better picture of the role of FADs in tuna behavior but we will also address the key question of the functional size of a tuna's ecosystem - at least as it pertains to remote archipelagos such as Hawaii. The appropriate data can be acquired by double tagging fish with both acoustic and data archiving tags. These tags will provide complementary information at different scales for the same fish. The acoustic tags will produce fine-scale data regarding the association of fish with instrumented FADs, while the archival tags will indicate if the fish remain in the general area of the island (Oahu) or leave to visit other islands or depart the Hawaiian archipelago completely. It is possible that some fish will be reacquired at the instrumented FADs after having left the area for prolonged periods - we have some preliminary data to show that this occurs. The archival tags should show us where these fish went. While the light-based geolocation data acquired by archival tags cannot provide fine-scale positional data, they can certainly provide data of sufficient precision to address the questions outlined above (Sibert et al., 2003).

Specific Objectives
The experiment will use three types of tags (coded acoustic, internal and external archival) to give short, medium and long-term movement and behavioral data for fish originally caught in association with Hawaiian coastal FADs. This protocol will elucidate the functional size of the ecosystem unit within which "Hawaiian" tuna exist.

  • Objective 1. Determine what role FADs play in the short, medium and long-term movement patterns of tuna. Determine the functional size of the pelagic ecosystem within which Hawaii resides.
  • Objective 2. Determine the impacts of FADs on the vertical movements of tuna and to determine if specific vertical distribution patterns can serve as a proxy for determining when tunas are associated with floating objects.
  • Objective 3. Test a newly developed tag anchor and attachment method for attaching pop-up tags to tunas and marlins The attachment system is based on veterinary and biomedical design principles enunciated by veterinarians, pathologists and fishery scientists who attended a PFRP-sponsored tag attachment workshop held in Hawaii in 2002 (Holland and Braun, 2003).
  • Objective 4. Collect data that will allow improvement of light-based geolocation algorithms.

Year 1 funding for this 2-year project to be available mid 2006.


Holland, Kim N. and Melinda J. Braun. 2003. Proceedings of "Tying One On" - A workshop on tag attachment techniques for large marine animals. SOEST Publication 03-02, JIMAR Contribution 03-349, 13 pp. (PDF, 164 KB).
Sibert, J., M. K. Musyl and R. W. Brill. 2003. Horizontal movements of bigeye tuna (Thunnus obesus) near Hawaii determined by Kalman filter analysis of archival tagging data. Fisheries Oceanography 12(3) 141-148.
Sibert, John, Scott McCreary, and Eric Poncelet, 2005. Pacific Ocean Connections: Priorities for pelagic fisheries research in the twenty-first century. Report of PFRP Research Priorities Workshop, November 16-18, 2005, SOEST Publication 06-01, JIMAR Contribution 06-358, 25 pp. (PDF, 393 KB)

Principal Investigators:

Dr. Kim Holland
Hawaii Institute of Marine Biology (HIMB)
University of Hawaii at Manoa
Coconut Island
P.O. Box 1346
Kaneohe, Hawaii 96744 USA
Phone (808) 236-7410/533-4110
FAX (808) 236-7443
email: kholland@hawaii.edu


Dr. Laurent Dagorn
Centre de Recherche Halieutique
Avenue Jean Monnet - BP 171
34203 Sete cedex
email: dagorn@ird.fr
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This page updated September 29, 2010