The first year of the resumed O'io Tagging Project has been a great success. It could not have been done without the time and commitment of all our volunteers. Most deserving of the biggest mahalo is Richard “Dick” Gushman. Without his passion for fly-fishing and bonefish, a great project could have stayed shelved. The 2003-2006 O'io Tagging Project was the solid foundation from which the 2008 project flourished. Dr. Bruce Anderson, Oceanic Institute, and Sean Niesz with his partners at Nervous Water Fly Fishers shop in Honolulu put forth the groundwork for a successful tagging project.
In addition many of the anglers involved with the previous program were asked to start tagging o'io once again and to report their catches using the new interactive ‘Ō‘ io Tagging Project website. Through the involvement of members of the Windward Surfcasting Club, Pacific Island Fishing Group, Atlapac Fishing Club, and Kaneohe Marine Corp Base volunteer auxiliary wardens, along with advertising in local tackle shops, membership has grown steadily. With gratitude towards Annette Tagawa and Clay Tam from State of Hawai‘i’s Papio/ Ulua Tagging Program for their help, invitations were mailed to all papio and ulua taggers asking them to the participate with tagging o'io. In 2008-2009 the O'io Tagging Project was present at many shore line fishing tournaments to publicize the project and resulted in many anglers signing up. A tag-and-release category for o'io tournaments may be in the future. Since November 2009 membership has reached 250
volunteers and 456 fish have been tagged!
I would like to acknowledge the support and advisement of Dr. Alan Friedlander, Hawaii Cooperative Fishery Research Unit and Kurt Kawamoto, NOAA for their support in the O'io Tagging Project. Their direction has been appreciated and instrumental in our success. Most of all, I want to thank all the anglers in the Hawaiian ‘o'io community who have gone out of their way to help and support the O'ioTagging Project.
Mahalo Nui Loa,
Kimberlee Harding
O'io Tagging Project Coordinator
WHY DO WE TAG FISH?
Traditional Hawaiian fishing values stressed conservative, biologically sound harvest constraints. Fishing practices were developed from observations of marine resources and seasonal patterns that spanned many generations. Programs like the O'io Tagging Project have been created to regain a better understanding of our local fish stocks and to promote the conservation of Hawaii’s o'io population for future generations.
The O'io Tagging Project began with a few anticipated outcomes: examine fishing success by time and location, determine habitat use and migratory patterns, and estimation of population abundance, growth, and mortality (rate of death). Anglers are asked to provide the location, date, how long the fishing trip lasted, and the specific time each fish is caught. This catch data is being analyzed by location for apparent trends with seasons, lunar cycles, and tidal cycles. This is useful information for the fishery; however the most vital component of the project is the reporting of recaptured tagged fish.
From recapture data, we can determine if and for how long an animal remained within a particular area or if the fish migrated due to seasonal patterns such as changes in food abundance or
reproductive activity. Original tagging information compared with recapture data provides information on fish movement and for individual growth rates. With the aid of mathematical models the amount of fish tagged and the amount of fish recaptured is used to estimate population size and rates of death. The more fish tagged and reported, the better the estimates.
Catch-per-unit-effort (CPUE) is calculated from the start and finish times of each fishing trip and how many fish were caught between those times (i.e. number of fish caught per hour). This number also demonstrates catch rates that may or may not be directly related to the population size. This tagging project, in conjunction with other surveys and reported commercial landings, provides a more accurate estimate on the recreational angler harvest. Your efforts help determine how the recreational fishery impacts the population. Ultimately, these data will be used to help determine the status of the entire stock thereby providing fishery managers with valuable information that will help to sustain the o'io resources of Hawaii.
O'io, the Hawaiian name for bonefish (Albula spp.), are highly sought after game fish worldwide due to their elusive behavior and strong fight once hooked. Across the Pacific, including Hawaii, many recreational anglers have begun the practice of catch-and-release of bonefish and in the Western Atlantic the recreational bonefish fishery is almost exclusively catch-and-release. Despite
the growing consensus amongst anglers that releasing fish is beneficial for the fishery, little is known on how catch-and-release activities affect bonefish once released.
With the creation of tag-and-release projects for bonefish in both Hawaii and Florida, concerns have grown that the extra handling to insert the tag and measure the fish induces too much stress and decreases the chance of survival after release. Before 2007 few studies had been conducted on any catch-and-release fisheries and even fewer studies focused on survival rates after release.
Due to the growing popularity of the catch-and-release bonefish fishery, researchers have conducted experiments to test how bonefish are affected once they are released.
Studies have been conducted in the Bahamas, Palmyra, and in the Florida Keys on captive bonefish held in a lagoon. Many things affect a fish’s health after an angling event. Factors such as fight time, air exposure, water temperature, and available cover for a fish to rest under are all important for the health of the fish post release; and other factors such as the fish’s body length, bleeding at the hook site and the amount of predators in an area are also considerations.
Physical stress and recovery rates in bonefish can be measured by looking at blood lactic acid concentrations, an anaerobic metabolite associated with high intensity exercise.
Bonefish in Palmyra were caught by hook-and-line and blood was drawn by syringe within two minutes. The fish were then placed into large holding pens. Blood lactate levels were found to be within normal ranges after the first blood sample, but increased by 7-fold after 24 hours. Levels returned back to normal by 36 hours.
In the Bahamas, captured wild bonefish were taken into a laboratory, placed into a large holding tank to acclimate for 48 hours, and then each fish was placed in a darkened individual tank for another 36 hours. Some of the fish were euthanized and blood was drawn within 45 seconds, other fish were exercised by tail grabbing for four minutes. This activity has been shown to mimic
physical changes caused by fishing. Various trials were conducted subjecting fish to different durations of air exposure and various recovery times to realistically replicate catch-tag-and-release events. Also, fish were observed during recovery times to note loss of equilibrium behavior.
The results from these trials showed that air exposure is the most influencing factor of whether a fish will lose its equilibrium, longer exposure to air caused blood lactate levels to increase regardless of the exercise time. When fish were exposed to one minute of air, lactate levels increased three times higher compared to fish not exposed to air; and fish exposed to three minutes of air required over 10 times longer to regain its equilibrium than fish exposed to one minute of air. Water temperatures and body size were not as significant for predicting a fish’s chance of losing equilibrium.
However, body size and temperature can influence the health and behavior of fishes that might contribute indirectly to the probability of survival after release. High water temperatures beyond usual limits can increase physical stress, especially following exertion. As water temperatures increased bonefish were observed “resting” for longer periods of time compared to fish in lower water temperatures. The only bonefish that died in the 2007 experiments by means other than predation, occurred when temperatures were greater than 95° F. After its release it
swam for 52 minutes before losing equilibrium and stopped breathing.
Bonefish losing equilibrium before release were over six times more likely to be killed by predators than fish that did not lose their equilibrium. However, in areas with intermediate numbers of predators, it was observed that if bonefish are able to avoid the predators for the first few minutes following release, their chance of survival was high even with rough treatment. It was also observed that bonefish had an excellent chance of survival if predator numbers in the area were low. Even when bonefish had lost their equilibrium, showed extreme exhaustion and stayed stationary near their release site for up to 30 minutes; they were still not attacked by predators. Furthermore, when bonefish were held in a large lagoon without predators, individual fish were caught and released up to ten times and the rate of death was very small.
The results from these studies are very positive for the catch-tag-and-release o'io fishery of Hawaii. Local water temperatures range from 76° to 81°F, which are much lower than
temperatures found to be detrimental to bonefish health. Predator densities are higher in the Bahamas compared to Oahu. The Bahamas studies consider the study area with the highest density of predators to be only at intermediate levels, observing one shark every hour and the Hawaiian Islands are considered to have a low predator density according to the author of the Palmyra study.
In a study he conducted found that predators comprise only 3 percent of total fish biomass of all the main Hawaiian Islands and O ahu has the lowest proportion of all the islands. The most important information for Hawaii anglers is to keep your catch in the water and limit its air exposure to less than 1 minute. It is also recommended that if you observe predators in the area keep your o'io in a live well, a cooler or another suitable container until the ‘ō’io has regained its equilibrium or the predator leaves the area. This practice would be difficult while wade fishing, so moving the bonefish to another area is also recommended.
Journal Articles Summarized In This Newsletter
Cooke, S.J. and Philipp, D.P. (2004) Behavior and mortality of caught-and-released bonefish (Albula spp.) in Bahamian waters with implications for a sustainable recreational fishery. Biological Conservation 118:599-607
Crabtree R.E., Snodgrass D. & Harnden C. (1998) Survival rates of bonefish, Albula vulpes, caught on hook-and-line gear and released based on capture and release of captive bonefish in a pond in the Florida Keys. In: Investigations into Nearshore and Estuarine Gamefish Abundance, Ecology and Life History in Florida, Five Year Technical Report to the US Fish and Wildlife Service, Sport Fish Restoration Project F-59. St Petersburg, FL, USA: Florida Marine Research Institute, pp. 252–254.
Danylchuk, S.E., Danylchuk, A.J., Cooke, S.J., Goldberg,T.L., Koppelman, J., Philipp, D.P. (2007) Effects of recreational angling on the post-release behavior and predation of bonefish (Albula vulpes): The role of equilibrium status at the time of release. Journal of Experimental Marine Biology and Ecology 346:127-133
Danylchuk, A.J., Danylchuk, S.E., Cooke, S.J., Goldberg, T.L., Koppelman, J.B., Philipp, D.P. (2007) Post-release mortality of bonefish, Albula vulpes, exposed to different handling practices during catch-and-release angling in Eleuthera, The Bahamas. Fisheries Managament and Ecology. 14:149-154
Friedlander, A.M., Caselle, J. E., Beets, J., Lowe, C. G., Bowen, B. W., Ogawa, T. K., -Kelly, K. M., Calitri, T., Lange, M., and Anderson, B. S. 2008. Biology and ecology of the recreational bonefish fishery at Palmyra Atoll National Wildlife Refuge with comparisons to other Pacific Islands. P. 27-56. In J.S. Ault [ed.] Biology and management of the world tarpon and bonefish fisheries. CRC Press
Friedlander AM, DeMartini EE (2006) Contrasts in density, size, and biomass of reef fishes between the northwestern and the main Hawaiian islands: the effects of fishing down apex predators. Marine Ecology Progressive Series 230:253-264
Suski, C.D., Cooke, S.J., Danylchuk, A.J., O’Connor, C.M., Gravel, M. Redpath, T., Hanson, K.C., Gingerich, A.J., Murchie, K.J. Danylchuk, S.E., Koppelman, J., Goldberg,T.L. (2007) Physiological disturbance and recovery dynamics of bonefish (Albula vulpes), a tropical marine fish, in response to variable exercise and exposure to air. Comparative Biochemistry and Physiology, Part A 148:664-673
The Oceanic Institute
Kimberlee Harding
O'io Tagging Project
41-202 Kalanianaole Highway
Waimanalo, Hawaii 96795