The Inter-American Tropical Tuna

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1 by Daniel Margulies, Vernon P Scholey, Jeanne B Wexler, Maria S Stein, Richard B Deriso and Guillermo A Compean The Inter-American Tropical Tuna Commission () operates the Achotines Laboratory in the Republic of Panama, where captive yellowfin tuna (Thunnus albacares) have been spawning almost daily since The Achotines Laboratory is the only facility in the world with nearly year-round availability of tuna eggs and larvae for research purposes. Yellowfin eggs, larvae and juveniles resulting from the near-daily spawns are used for a variety of studies, including investigations of the effects of various environmental and biological factors on growth and survival of tunas in their early life stages. Research focuses on areas of tuna ecology and biology that will provide important information for population estimates and management of the stocks, but additional areas of research are also ongoing. The research is carried out by members of the Early Life History (ELH) Research Group of the. Researchers from other institutions also carry out investigations at Achotines Laboratory, often in collaboration with the s ELH scientists. In addition, the Laboratory supports research on coastal marine fish species carried out by biologists of the Autoridad de los Recursos Acuáticos de Panamá (ARAP). The laboratory site The laboratory is adjacent to Achotines Bay, in the province of Los Santos, on the southeastern tip of the Azuero Peninsula on the Pacific coast of the Republic of Panama. The annual range of sea-surface temperature in these waters is approximately C. The continental shelf off Achotines Bay is quite narrow: the water reaches depths of over 200 m less than 8 km from shore, affording scientists ready access to oceanic waters where spawning of tunas occurs during every month of the year. On land, the laboratory site includes a 120-hectare tropical dry forest, now the rarest of the major tropical ecosystems. Once this type of forest covered km 2 of the Pacific coast from Panama to Mexico; today only some km 2 remain intact, and of those less than 600 km 2 are officially protected. The majority of the trees in Los Santos province have been cleared for pasture and farming, but forest still covers over 70 hectares of the area immediately surrounding the laboratory, with the remaining 50 hectares undergoing rapid restoration. Located in Panama, the s Achotines Laboratory has chalked up an impressive record in carrying out research on tuna biology and ecology. It it is the only facility in the world with year-round availability of tuna eggs and larvae for research purposes. It also conducts research on local coastal species of finfish such as snappers and corvinas. Aeriel view of Achotines Laboratory Liam Scholey 24 INFOFISH International 2/2013

2 The Achotines Laboratory a world leader in tuna research AQUACULTURE Location of Achotines Laboratory The region is characterised by marked rainy and dry seasons and dynamic marine circulation patterns, resulting in a wide natural variability of the near-shore habitat. More than 150 species of fish have been collected in Achotines Bay and its immediate vicinity, including at least 10 species of tunas and billfishes. Achotines Bay contains one of the few mainland coral reefs found on the west coast of Central America. The nearby Frailes Islands are well-known seabird rookeries. A major nesting site for sea turtles is located nearby at Isla de Cañas, and several species of whales and dolphins can be sighted locally. Early research through 1993 involved laboratory and field studies of early life stages of nearshore tropical tunas. In 1992, scientists began collaborative work on the rearing of larval tunas with Japanese scientists in Japan. In 1993, this research led to a joint project centered at the Achotines Laboratory, initiated by the, the Overseas Fishery Cooperation Foundation (OFCF) of Japan, and the government of the Republic of Panama. The objective of the project was to investigate the culture and captive spawning of yellowfin tuna (Thunnus albacares), snapper (Lutjanidae), and corvina (Sciaenidae) in land-based tanks to provide larvae and juveniles for research purposes. The infrastructure expansion necessary to hold yellowfin tuna broodstock and to provide cultured food items for their larvae was completed by mid-1996, and construction of additional tanks and a concrete pier were completed by late Between 1993 and 2001, several Japanese scientists were based at the Achotines Laboratory, working with and Panamanian scientists on spawning and rearing programmes with yellowfin tuna, snapper and corvina. Facilities The research facilities of the Achotines Laboratory include six circular concrete tanks, one of 1300 m 3, two 170 m 3 and three 85 m 3, for broodstock fish, contained in a m 2 roofed, open-walled building. Other buildings contain facilities for incubating eggs, rearing larvae and juveniles, and producing algae and rotifers for feeding the fish, a library and small conference room, an analytical laboratory, a nutritional analysis laboratory, and a DNA laboratory. There is also office space and housing for scientists, a workshop, and a pier in Achotines Bay for vessel operations. Research on tunas Early studies of coastal tunas and mackerel Through 1994, near-shore tropical tunas, including early-juvenile black skipjack, bullet and/or frigate tunas (Auxis spp), and sierra (Scomberomorus sierra), were collected at sea and reared at the laboratory. This series of experiments resulted in published studies of the nutrition, ageing and growth, physiology and development of vision in these species. History As tunas are pelagic (open-ocean) fish they are difficult to study in their natural habitat. In the early 1980s, the decided that a field laboratory was needed to study the reproductive biology and early life history of tunas, and in 1984 purchased the site of the present Achotines Laboratory. Research activities were initiated in 1985 and a large expansion of laboratory infrastructure occurred from Yellowfin grow to reproductive size and spawn in the main broodstock tank. INFOFISH International 2/

3 The Achotines Laboratory a world leader in tuna research Yellowfin eggs shortly before hatching. Larval surveys conducted at sea in coastal waters near the Laboratory resulted in publications describing the temporal and spatial patterns of distribution and at-sea starvation rates of tuna larvae in the Panama Bight. From 1992 to 1994, adult black skipjack captured in the wild spawned for extended periods in the laboratory. The eggs and larvae hatched in captivity were used in several laboratory experiments to describe the early development and growth of the species. By 1996, with the expansion of the laboratory facilities, research emphasis at Achotines shifted to the spawning and rearing of yellowfin tuna. Capture, transport and growth of yellowfin broodstock In early 1996, a yellowfin broodstock population was first established in landbased tanks at the Achotines Laboratory. Over the past 16 years, yellowfin have been caught in waters close to Achotines Bay, using rod and reel or hand lines, and transported to the Laboratory in tanks aboard skiffs. Prior to stocking in the laboratory tanks, the fish are measured, weighed, tagged with a microchip implant tag in the dorsal musculature, and injected with oxytetracycline (OTC). The tag allows each fish to be identified throughout its life in captivity, and injection with OTC establishes a temporal mark in the otoliths and vertebrae, useful for studies of the growth of the fish. The m 3 main tuna broodstock tank was designed to be large enough to reduce the stress of captivity and enhance the chances of yellowfin spawning. Since 1996, multiple groups of yellowfin have been maintained in the main broodstock tank. The average residency time in the main tank has been approximately 2 years, although individual fish have been held for up to almost 6 years. The broodstock yellowfin are fed a diet of squid, herring, and anchovy, supplemented with vitamins and minerals, at approximately % of their body weight per day. Growth rates for 2-3 year old yellowfin in the main broodstock tank have ranged from kg/day. Over 16 years, the broodstock population in the main tank has ranged from a maximum of 44 fish to a minimum of 6 fish. In September 2012, the tank contained 12 yellowfin, ranging in weight from about 12 to 65 kg. Yellowfin spawning Yellowfin tuna in the main broodstock tank have been spawning almost daily since October To our knowledge, this represents the only successful long-term spawning of yellowfin in land-based tanks anywhere in the world. Spawning generally occurs from early afternoon to late evening. The spawning events are usually preceded by several hours of courtship behaviour (paired swimming, chasing). Spawning can be intermittent during February and March, when offshore upwelling, induced by northerly winds of the dry season, brings cooler water temperatures near-shore and into the rearing tanks. The numbers of fertilised eggs collected after each spawning event in the main broodstock tank range from several hundred to several million. The eggs are collected by several methods, including siphoning and dipnetting at the surface and seining with a finemesh surface egg seine. Fertilised eggs are hatched in 240-litre cylindrical incubation tanks. In a series of publications, the s ELH group has described the methods of broodstock development, reproductive biology, spawning dynamics, courtship and spawning behaviour and genetics of captive yellowfin. Studies of yellowfin eggs, larvae, and juveniles The larvae hatched from eggs spawned in captivity at the Achotines Laboratory are used in a variety of laboratory experiments. In several publications, the s ELH group has described the growth, survival, and early development of yellowfin tuna. Additional publications have described the effects of key physical variables (water temperature, dissolved oxygen, microturbulence, and light intensity) on growth and survival of yellowfin larvae. Results from several recent experimental studies at Achotines appear to have potential as forecasting tools for understanding pre-recruit survival of yellowfin in the eastern Pacific Ocean (EPO). These forecasting tools include the use of wind speed data (representative of wind-induced microturbulence and its effect on larval feeding success) and a larval growth index to predict pre-recruit survival of yellowfin. The experimental programme at the Achotines Clockwise from left: Yellowfin larvae at first-feeding stage (3.5 mm in length); yellowfin larvae 15 days old (7 mm in length); yellowfin late-stage larva (11 mm in length) collected at sea. 26 INFOFISH International 2/2013

4 The Achotines Laboratory a world leader in tuna research AQUACULTURE Daniel Benetti Early-juvenile yellowfin, 30 days old (25 mm in length) in rearing tank at Achotines Laboratory. Laboratory has led to advances in the rearing of larval and early-juvenile tunas. The s ELH scientists routinely rear early-juvenile yellowfin tuna up to days after hatch for research purposes, and have reared yellowfin up to 100 days after hatch. A summary of research findings from studies conducted at the Achotines Laboratory through 2006 is presented in Special Report No 16 (2007), available on the website. Experimental topics of study with yellowfin at the Achotines Laboratory have expanded in recent years. The effects of ocean acidification are receiving increased attention worldwide. For tuna, early life stages are sensitive to environmental changes but potential impacts of ocean acidification on tuna populations are unknown. Research trials were completed at the Achotines Laboratory in late 2011 examining the potential effects of ocean acidification on the survival and growth of yellowfin eggs and larvae. These trials were conducted in collaboration with scientists from the Secretariat of the Pacific Community (SPC), and were funded by the Pelagic Fisheries Research Programme (PFRP) of the University of Hawaii. In 2010 and 2011, eggs and/or larvae of yellowfin tuna were successfully shipped by air from the Achotines Laboratory to the Hubbs Sea World Research Institute (HSWRI) in San Diego, California, USA, as part of a feasibility study funded by the Saltonstall-Kennedy Programme, US National Oceanic and Atmospheric Administration (NOAA). The study proved that it is possible to send these kinds of samples from Panama to the United States for research purposes, and the success of the project was instrumental in the and HSWRI recently being awarded a California Sea Grant project designed to continue and expand the air shipment trials. The new project began in May 2012, and will continue for 3 years. Comparative studies of yellowfin and Pacific bluefin early life history In January 2011, the, Kinki University of Japan, and ARAP began a Reader enquiry number 6 INFOFISH International 2/

5 The Achotines Laboratory a world leader in tuna research comparative study of the early life history and reproductive biology of yellowfin tuna and Pacific bluefin tuna. This joint research project is being conducted by faculty and staff of Kinki University, the ELH Group of the, and scientists of ARAP, mostly at the Fisheries Laboratory of Kinki University and the Achotines Laboratory, and will continue through March The study will be the first in the world to investigate important comparative aspects of the reproductive biology, genetics, and early life history of these two species of tunas. The project will also support graduate research through Kinki University for selected members of all three participating groups. It is being implemented under the Science and Technology Research Partnership for Sustainable Development (SATREPS); the studies conducted in Japan are supported by the Japan Science and Technology Agency (JST), and those in Panama by the Japan International Cooperation Agency (JICA). -University of Miami annual workshop Since 2003, the and the University of Miami s Aquaculture Programme have jointly hosted an annual workshop entitled Physiology and Aquaculture of Pelagics with Emphasis on Reproduction and Early Developmental Stages of Yellowfin Tuna at the Achotines Laboratory. International researchers, industry professionals and University of Miami graduate students gather to study and share advanced technologies and improved methods for experimental studies and rearing of larval tunas and other species of marine fish. A fee for the participants and students covers the expenses of conducting the workshop. Research on snappers and corvinas Spawning and rearing of snappers and corvinas Research on local coastal species of fish is also conducted at the Achotines Laboratory. The Panamanian government agency Dirección General de Recursos Marinos y Costeros (DGRMC) conducted studies of spotted rose snappers (Lutjanus guttatus) and corvina (Umbrina xanti) from 1996 through 2006, at which time the DGRMC was integrated into ARAP. An ARAP scientist, working with Laboratory staff and visiting Japanese scientists, established spawning broodstock populations of polla drum, a species of corvina, and spotted rose snappers in 1996 and This represented the first successful spawning in captivity for both of these species. The corvina broodstock was maintained through Since 1996, ARAP staff have conducted full life cycle research on spotted rose snapper in captivity. Multiple generations of this species have been held at the Laboratory, but the broodstock populations decreased in numbers in Current research efforts are directed at rebuilding this broodstock. The research objective is to complete the life cycle of spotted rose snapper in captivity and to study the growth patterns and feeding requirements of the juveniles. Collaborative research In addition to the joint research projects described above, the maintains close affiliations with other universities, government agencies, and private research organisations and institutions at local, national, and international levels. Scientists from the following institutions have conducted collaborative or independent research at the Achotines Laboratory: University of Tokyo (Japan), Universidad de Panamá (Panama), University of Istanbul (Turkey), University of Washington, Cornell University, University of Michigan, California State University at Fullerton, Northern Arizona University, Yale University, Princeton University, University of Miami (USA), Florida Marine Research Institute, the US NOAA Fisheries Service, Universidad de Oriente (Venezuela), Australian Institute of Marine Science, Japan Sea Farming Association, and the Smithsonian Tropical Research Institute. Future directions From modest beginnings, the s Achotines Laboratory has developed into one of the premier tuna research laboratories in the world. With high quality research facilities situated in a tropical environment, the Achotines Laboratory provides researchers with a unique setting for conducting research on tropical tunas, especially yellowfin tuna. For more information on the Achotines Laboratory, including descriptions of research programmes and a full list of scientific publications based on research conducted at the Laboratory, go to the Laboratory website at AchotinesDefaultENG.htm. The authors (left to right): Vernon P Scholey (Senior Scientist), Daniel Margulies (Senior Scientist), Maria S Stein (Assistant Scientist), Guillermo A Compean (Director), Jeanne B Wexler (Associate Scientist) and Richard B Deriso (Chief Scientist). The authors are all attached to the Achotines Laboratory. Please see photo at left for their titles. Reader enquiry number 7 28 INFOFISH International 2/2013