`o`io (bonefish) tag-and-release angler-based program

Alan Friedlander, Bruce S. Anderson, and David Ziemann
Oceanic Institute, Waimanalo, Hawaii

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Statement of problem

  • Many of Hawaii's coastal fisheries species have declined in abundance
  • ?o?io (bonefish) are a highly prized recreational and subsistence species that has shown dramatic declines in commercial catch over the past several decades.
  • Two species of ?o?io exist in Hawaii and fishery and life-history information necessary for effective management is lacking for both species.

Benefits

  • Provide critical information (e.g., catch, effort, size) for the management of the 'o'io (bonefish) resources and the fishery in Hawaii
  • Provide species-specific biological information (e.g., size, movement, growth, etc.) for fishes that are important to the ecology, economy, and culture of Hawaii.
  • Provide information on species that has not been well studied in the Pacific

Research Focus

  • Examine fishing success by time (e.g., seasonal, tidal, etc.) and location
  • Determine habitat use and migratory patterns
  • Estimate population abundance, growth, and mortality
  • Determine status of fish stocks

Methods

  • Logbooks will be kept by a group of dedicated volunteer anglers to document fishing catch and effort. These data will provide valuable information on productivity of each area along with the size structure of fish by area and during various lunar and seasonal cycles.
  • Tagging of fish by a group of dedicated volunteer anglers will be conducted to examine population size, movement of fish, fidelity to certain areas, migration routes, and growth.
  • Collaboration between anglers and researchers is critical for the success of this program. Data will be analyzed in a timely manner and disseminated through reports, presentations, newsletters, and other appropriate mediums and venues.

Introduction

It is well established that coastal fisheries in Hawai'i have declined significantly over the past several decades (Friedlander and DeMartini 2002, Shomura 2004, Friedlander and Ziemann 2003). Commercial landings have declined for a number of important resource species but there is little information on the catch by recreational and subsistence fishers, which is thought to be considerable. In addition to the lack of good information on fishing catch and effort, there is also a lack of life history information on even the most important resource species. This information is critical for conducting stock assessments and developing biologically relevant management strategies. The State of Hawai'i Local Action Strategy on Fishing has identified the lack of life-history information on resource species as one of the most urgent and critical research needs for effective management.

Bonefish are important in many coral reef environments around the world?both ecologically and economically. They are have cultural important for many Pacific Islands (Johannes and Yeeting 2000, Beets 2000). Bonefish were an important food resource for early Hawaiians and are targeted today by a mix of commercial, recreational, and subsistence fishers. Commercial landings of bonefish in Hawai'i have declined from over 300,000 lbs. in 1900 to only a few thousand pounds in 2001 (Figure 1). Many recreational anglers in Hawai'i used bait to catch bonefish, although a small fly-fish fishery exists on Oahu. State regulations have recently raised minimum size from 23 cm (9 in.) TL to 36 cm (14 in.) FL, although there is neither a closed season nor a bag limit.

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Because of the elusive nature of bonefish, much of the information necessary to manage this species can only be obtained through the efforts of anglers and guides. Collaboration with anglers and guides provided valuable data as well as helped formulate recommendations for bonefish management. The research will be aimed at learning more about the life history, population dynamics, and behavior of bonefish so that bonefish can be more effectively managed.

Methods

Bonefish Catch and Effort Logbooks

The purpose of the catch and effort logbook program is to examine fishing success and status of bonefish stocks in Hawai'i. These data will also help to examine productivity and size structure of bonefish at specific locations as well as seasonal and lunar periodicity. The overall goal is to have the best available scientific data to help develop an effective management strategy for bonefish.

The angler logbook program will collect and analyze data on fishing effort (time, gear type, location), catch (time, location, fish size, reproductive state), and environmental conditions (e.g., lunar phase, tidal phase, water depth, weather conditions) in order to describe trends and identify relationships. The program will require rigorous reporting.

Waterproof logbooks will be provided to anglers. The information contained in the logbooks will include: (1) date (2) location (3) start time (4) finish time (5) number of anglers (6) skill level of anglers (7) number caught (8) number hooked (9) species caught, (10) comments (size of schools, movement, weather, etc.). A database will be developed to store and analyze logbook data.

Tag-and-release program

The purpose of the tagging program is to examine movement, fidelity to certain areas, migration routes, and growth of bonefish in Hawaii. These data will be invaluable in estimating population size, determining productivity of various locations, and helping to estimate growth parameters. The overall goal is to have the best available scientific data to help develop an effective management strategy for bonefish at Hawaii. Tagging can only be conducted with the assistance of anglers and guides and cooperation in this program will greatly aid in developing best management practices for bonefish in Hawaii.

In 2003, an o?io tagging program was initiated to characterize the resource for the purpose of supporting appropriate resource management and conservation programs, as well as helping to encourage a catch-and-release ethic among fisherman. Volunteers reported that they were able to clearly distinguish the two species of o?io in Hawaii based on the descriptions and photographs provided in the tagging instructions. A total of 1147 o?io were tagged between May 2003 and February 2006. Of the fish identified to species, 81% were roundjaw. The vast majority of sharpjaws (72%) were captured in Kaneohe Bay. It is reported that this species inhabitants the deeper channels in the bay and utilizes different habitats than the roundjaw. On average, the roundjaws are larger (mean = 20.3 in.) than the sharpjaws (mean = 15.9 in.) (Figure 2). The largest roundjaw was 39 inches while the largest sharpjaw was only 23 inches.

The major tagging locations included Kaneohe Bay, Hickam/Keehi Lagoon, and Hawaii Kai (Figure 3). Other important o?io fishing locations were Kailua, Ewa, Ala Moana, and Waikiki. These locations may reflect access and distance to population centers rather than abundance of oio.

Of the 1,147 o?io tagged, there were 19 total recaptures (1.6% recapture rate), with one individual recaptured twice. Most fish were recaptured close to their initial tagging location but one fish tagged off Hawaii Kai recaptured off of Kanaukaka Harbor on Molokai after 609 days at-large (Fig. x). The average time at-large was 290 days with a maximum of 792 and a minimum of 5 hours. The average distance traveled was 4.6 miles, and 2.0 miles excluding the one Molokai fish.

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Discussions and recommendations

O?io have been, and continue to be an important species in Hawaii. Declines in commercial catch and juvenile recruitment indicate that local stocks of o?io are not as healthy as they once were. Nearly 22,000 lbs of o?io were taken in lay gillnets between 1997 and 2006. The recently exacted partial ban on lay gillnets may help to improve the health of stocks and it is therefore important to monitor the status of bonefish stocks at this time.

The tag-and-release program has provided valuable information on o?io biology and the recreational fishery. It has also helped to encourage anglers to release their catch. The tagging program has also been an effective public education tool. There is still much to be learned about the biology and fisheries for o?io in Hawaii. In addition, we need to understand the dynamics between the two species of o?io present in Hawaii and how they interact with one another and their environment. Effective management requires a sound understanding of biology and fisheries dynamics of the species and information provided by this work will greatly aid in the development of better management and improved angler ethics related to these and other species in Hawaii.

References

Beets, J., Declines in finfish resources in Tarawa Lagoon, Kiribati, emphasize the need for increased conservation effort, Atoll Research Bulletin, 490, 1-14, 2000.

Friedlander, A.M., and DeMartini, E.E., 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 Progress Series, 230, 253?264, 2002.

 

Friedlander, A.M. and D.A. Ziemann. 2003. Impact of hatchery releases on the recreational fishery for Pacific threadfin in Hawaii.  Fishery Bulletin. 101:32-43.

Johannes, R.E., and Yeeting, B., I-Kiribati knowledge and management of Tarawa's lagoon resources, Atoll Research Bulletin, 498, 1-24, 2000.

Shomura, R. 2004. A historical perspective of Hawaii?s marine resources, fisheries, and management issues over the past 100 years. Pages 6-11 in: Friedlander, A.M. (ed.) Status of Hawaii?s coastal fisheries in the new millennium. Proceedings of a symposium sponsored by the American Fisheries Society, Hawaii Chapter. Honolulu, Hawaii.