Research
Why are pelagic fishes attracted to FADs? How do the fish find the FADs? How long do they stay around the FADs? These are important questions that researchers at the University of Hawaii and other collaborating institutions have been trying to answer. The FAD system not only provides fishermen with better opportunities to catch fish, but also provides scientists with an opportunity to learn more about the biology and behavior of these hard to study pelagic fishes.
Why are pelagic fishes attracted to FADs?
Researchers at the University of Hawaii have begun to get answers to this question using several different techniques. In order to determine the short-term movement patterns of tunas, researcher attach acoustic transmitters to fish caught at FADs and follow them around for up to 48 hours to see where they go. Using this technique, they have found that subadult yellowfin tuna caught around FADs spend their days around the FADs but leave them at night and venture off as far as 5 miles. This information can be valuable in helping FAD managers determine how far apart FADs should be. Acoustic transmitters attached to the fish also relay information about their depth. Studies have shown that small bigeye tuna spend more time closer to the surface around FADs than when they are in free schools away from the FADs.
In another use of acoustic transmitters, data loggers attached to some FAD moorings are monitoring the longer term movement patterns of tunas returning to the FADs.
These studies have found that tunas tagged around seamounts behave very similarly to tunas tagged around FADs. It is thought that maybe the FAD serves the same function as a seamount, providing a point of reference for the tuna.
In the near future, standard tag-and-release research will be conducted to investigate the long term movement patterns of tunas around FADs and their influence on the movement patterns of tunas in Hawaiian waters in general.
Scientific Literature Arising from Hawaii FAD research
Refereed Publications
Adam, S.M., J.R. Sibert, D. Itano and K.N. Holland. 2002. Dynamics of bigeye and yellowfin tuna in Hawaii’s pelagic fisheries: analysis of tagging data using a bulk transfer model incorporating size specific attrition. Fish.Bull.101(2):215-228
Dagorn, L. C., K.N. Holland and D. G. Itano. 2007. Behavior of Yellowfin (Thunnus albacares) and Bigeye (Thunnus obesus) tuna in a network of fish aggregating devices (FADs). Marine Biology. 151(2): 595-606
Dagorn L, Holland K, Dalen J, Brault P, Vrignaud C, Josse E, Moreno G, Brehmer P, Nottestad L, Georgakarakos S, Trigonis V, Taquet M, Aumeeruddy R, Girard C, Itano D, Sancho G. 2007. New instruments to observe pelagic fish around FADs: satellite-linked acoustic receivers and buoys with sonar and cameras. In: Lyle J.M., Furlani D.M., Buxton C.D. (Eds), Cutting-edge technologies in fish and fisheries science. Australian Society for Fish Biology Workshop Proceedings, Hobart, Tasmania, August 2006, Australian Society for Fish Biology.
Graham, B., R.D. Grubbs, K.N. Holland and B. Popp. 2007. A rapid ontogenic shift in the diet of juvenile yellowfin tuna from Hawaii. Marine Biology. 150(4):647-658
Holland, K.N. 1996. Biological Aspects of the Association of Tunas with Fish Aggregating Devices. FAD Newsltr. (2):1-8. South Pacific Commission, Noumea, New Caledonia.
Holland, K.N., R.W. Brill and R.K.C. Chang. 1990. Horizontal and vertical movements of yellowfin and bigeye tuna associated with fish aggregation devices. Fish. Bull. 88:493-507.
Holland, K.N., Meyer C.G., Dagorn L.C. 2009. Inter-animal telemetry: results from first deployment of acoustic ‘business card’ tags. Endangered Species Res. doi: 10.3354/esr00226.
Holland, K.N and J.R. Sibert. 1994. Physiological thermoregulation in bigeye tuna (Thunnus obesus). Environ. Biol. Fish. 40:319-327.
Holland, K.N., A. Jaffe and W. Cortez. 2000. The FAD system of Hawaii. In: Peche thoniere et dispositifs de concentration de poissons (Le Gall and Tacquet, Eds). Actes du Colloques d'IFREMER 28. 288p.
Holland, K.N and R.D. Grubbs. 2007. Tunas and billfish at seamounts. In: Pitcher, T.J. et al. (Eds.) Seamounts: ecology, fisheries & conservation. Fish and Aquatic Resources Series, 12: pp. 189-201. Blackwell Press
Itano D G. and K.N. Holland. 2000. Tags and FADs - movements and vulnerability of bigeye tunas in relation to FADs and natural aggregation points. Aqua. Liv. Res. 13(4): 213-223.
Sibert, J.R., K.N. Holland and D. G. Itano. 2000. Exchange rates of yellowfin and bigeye tunas and fishery interaction between Cross Seamount and nearshore FADs in Hawaii. Aqua. Liv. Res 13(4) 225-232.
Technical Reports
Grubbs, R.D., K.N. Holland and D. Itano. 2001. Food Habits and trophic dynamics of structure-associated aggregations of yellowfin and bigeye tuna in the Hawaiian Islands: Project description, rationale and preliminary results. Technical Report to the 14th meeting of the Standing Committee on Tuna and Billfish. Noumea, New Caledonia
Grubbs, R.D., K.N. Holland and D Itano. 2002. Comparative trophic ecology of yellowfin and bigeye tuna associated with natural and man-made aggregation sites in Hawaii. Technical Report to the 15th meeting of the SPC Standing Committee on Tuna and Billfish. Honolulu.
Holland, K.N., R.D. Grubbs, B. Graham, D. Itano and L. Dagorn. 2003. FAD-associated tuna: Temporal dynamics of association and feeding ecology. Technical Report to the 16th meeting of the SPC Standing Committee on Tuna and Billfish. Mooloolaba, Australia
Itano, D., K Holland, L. Dagorn, D.G. Grubbs and Y. Papastamatiou. 2004. Monitoring movement patterns, residence times and feeding ecology of tuna, billfish and oceanic sharks within a network of anchored FADs. Technical Report to the 17th meeting of the Secretariat of the Pacific Community (SPC) Standing Committee on Tuna and Billfish, Majuro, Marshal Islands.
More pages related to FADs: