Blue Marlin Movements Tracked with Satellite Tags

This unique research effort is being undertaken by the TRCC scientists in cooperation with charter boat captains and recreational anglers, to monitor the movements, release survival parameters and water temperature preferences of Pacific blue marlin using the most recent and sophisticated satellite tagging and game fish catch-and-release technologies.

The Project
Release of live billfishes, in both recreational and commercial fisheries, is a common tool used to reduce billfish landings and promote conservation.

Tag-A-Billfish will utilize pop-up satellite archival tags to examine post-release survivorship and gather much needed information about the movements of blue marlin. Information on oceanic movements of the fish will be correlated with oceanographic features (sea surface temperature, ocean color, and currents) to provide new insight into one of the planet’s least understood pelagic fish.

Survivorship of billfishes after tag and release is not well documented and is critical information for assessing the costs and benefits of the practice for marlin caught in recreational and commercial fisheries. The objectives of this project are to place satellite tags on blue marlin and release them under the best possible condition by utilizing heavy tackle and experienced anglers to assist the scientists.

Detailed records of depth, temperature and movements will be examined for all fish. The tags will provide histogram summaries of depth and temperature preferences, and light data from which longitude and latitude can be estimated. The preference of blue marlin for surface waters will make light based geo-location extremely feasible.

We intend to deploy pop-up satellite archival tags on blue marlin in the Atlantic and Pacific. If the response from community based sponsorship of tags is favorable, we will be able to increase in the number of short and long term tags deployed.

Angler and Scientists have Cooperated for Over 40 Years to Tag and Release Gamefish
Cooperative tagging programs mounted by various national and private organizations over the last 40 years have been spectacularly successful not only in generating information about the movements of game fish, their age and growth, but also in building partnerships between the angling and scientific communities.

In Hawaii there is a 25-year history of research in association with the Pacific Ocean Research Foundation (PORF), which has established an excellent working relationship with the recreational anglers of Kona, Hawaii. Working together, over forty scientific publications on blue marlin have been published. Similar efforts have been achieved in the Atlantic with cooperative tagging occurring along the Eastern US seaboard especially in the Carolinas, in Madeira and off Bermuda. This cooperative effort of scientists and fishers has led to a large increase in our knowledge about blue marlin.

The scientists from the Tuna Research and Conservation Center (TRCC) together with PORF scientists have worked for two decades in Kona with the blue marlin fishery. We have substantial links with the recreational marlin fishery in Hawaii through Captain Rick Gaffney and Sue Vermillion and are looking to build a community integrated scientific research program.

TAG-A-BILLFISH Research Plan

The Technology
Recent technological advances in wildlife telemetry provide our team with new tools to directly examine behavior, short and long-term movement patterns and the global distribution of large pelagic fish. The successful implementation of both the pop-up satellite and archival tag technology has provided marine researchers with powerful new methodologies for studying large pelagic vertebrates.

Research Locations

One of the most active locations for research on pelagic fishes has been the prolific waters of the Kona coast, where calm, deep-water, close to shore, helps make this location an ideal study site. Over the past two decades, the PORF laboratory of Kona, Hawaii has accumulated behavioral, physiological and genetic data on blue marlin and tuna species in an effort to better understand the biology of these species. Many facets of marlin biology including research on reproduction, feeding behavior, local movements recorded via acoustic tracking, and physiological stress have been examined by PORF scientists over the past twenty plus years.

The success of research in Kona has in part been due to a close working relationship developed between the recreational fishing community and research scientists. This co-operative spirit has been nurtured by a culture in the Hawaiian Islands that respects the recreational troll fishery, and its associated tourist dollars as a valuable contribution to the local Hawaiian economy. The presence of this cooperative relationship between fishers and scientists provides the societal context, in parallel with the unique coastal oceanography, within which to conduct sophisticated scientific studies on pelagic game fish. The principal investigators are long established members of this co-operative research association and will implement the project in this working environment.

In the Atlantic Mr. Stuart Campbell has pioneered using pop-up satellite tags in Madeira, Portugal and The Canary Islands. Once again, in 2000, pop-up satellite tags were placed on large blue marlin for durations up to 1 year.

Tag and Release Ethic

In the past decade, sport fishermen have strongly supported the tag and release of blue marlin. The release ethic was developed in response to the over-fishing of many marine resources.

In 1997, the International Commission for the Conservation of Atlantic Tunas (ICCAT) adopted its first-ever-international recommendations for billfish conservation calling for reductions in blue marlin landings. The recommendation called upon both commercial and recreational fishers to reduce fishing effort and billfish landings and in effect promotes release of the fish. The recommendations follow recent assessments, which indicate the Atlantic blue marlin stocks are in a decline. U.S. fisheries operating in Atlantic waters comply with ICCAT recommendations and currently release most live marlin.

In the Pacific, blue marlin is also caught incidentally on tuna and swordfish longlines and is sometimes released. Tag and release has been prominent among recreational fishers throughout the Pacific (led by Australia and New Zealand fishers) and more recently, the Kona recreational fishery has begun to emerge as a proponent of the tag and release of blue marlin.

Survival of Tagged and Released Marlin

While release is often argued to be an effective management tool for reducing mortality, it is not certain how well tagged and released billfish survive. Survivorship studies assessing the ability of blue marlin to recover from capture on commercial and recreational fishing gear and subsequent release are needed to discern the effectiveness of live release in reducing overall mortality. Our will provide short and long term data on blue marlin caught on recreational gear under best possible tag and release conditions. Similar studies should be conducted on commercial gear to compare results.

Migrations

Our pop-up satellite tagging program will provide knowledge of blue marlin behavior and migratory routes throughout the Pacific Ocean basin. Previous Blue Marlin Tracking Research [link to Previous Research] demonstrated remarkable movements from both Kona and Madeira releases. One fish travelled 3000nm in 90 days. Long-term data records on distribution and movement patterns in relationship to environmental parameters are generally unknown and are required for development of international management plans. Our current understanding of the migrations and movement patterns of blue marlin are incomplete because of the inherent difficulties of studying open ocean fishes and historical lack of appropriate tools. The newest generation of pop-up archival tags have been successfully field-tested and are being purpose-built by Wildlife Computers for these studies.

Significance of Tag-A-Billfish for the Future

The increasing pressure that is being brought to bear on ocean resources around the world, means that we must obtain the data upon which proper management of these precious fisheries depends. To maintain strong recreational fisheries for blue marlin it will be increasingly important to demonstrate that blue marlin require international cooperation for their proper management. Pop-up satellite tagging has the potential to provide information on detailed movements, which can be related to remote oceanographic imagery of surface temperatures and oceanic productivity. Such data will provide the first spatial and temporal series on how and why blue marlin move throughout the Pacific basin.revious Blue Marlin Tracking Research