Posting taken from MPA News 11(1) July-August 2009
CASE 2 - WEST HAWAI`I: A network of reserves to replenish an aquarium fishery
In 1999 a multi-stakeholder working group on the west coast of the island of Hawai`i approved a proposal to designate a network of fishing closures (MPA News 1:1). The nine closures, called fish replenishment areas (FRAs), were intended primarily to address a long-standing user conflict between dive tour operators and aquarium fish collectors. In the FRAs, which covered approximately 35% of the 240-km West Hawai`i coastline, diving would be allowed and aquarium fish collecting would not.
Over the past 10 years, the network has helped reduce the level of conflict between the groups. But it has also had a clear effect on populations of the main target species for aquarium collectors - yellow tang. There is spillover of adult yellow tang occurring across the FRA boundaries, indicating the protected areas may play an important role in sustaining stocks over the long term.
Evidence of spillover:
In a paper published in the May 2009 issue of the journal Biological Conservation, a team of researchers showed that prior to designation of the FRA network, yellow tang densities were similar at sites open to fishing and those slated for closure. By 2007, however, the closed areas had five times the density of target-sized fish, and 48% higher density of adults than open areas. The main evidence of spillover was this: densities of adults in so-called "boundary" areas (open areas less than 1 km from nearest MPA boundary) were significantly higher than in open areas far from MPA boundaries.
In light of the fact that the number of active aquarium fishers along the coast doubled from 1999 to 2007, as did the total catch of yellow tang, the authors suggested that the protected areas could be essential for supplying adult fishes to keep the fishery going. "The West Hawai`i protected area network, by sustaining adult stocks over large areas of the coastline, acts as a bulwark against overexploitation," wrote the research team, which included government and academic scientists.
The yellow tang fishery is relatively unique, at least compared to most commercial food fisheries. The prime target size for yellow tangs is 5-10 cm; this is when they are usually less than two years old and still juvenile. Adults on the other hand are not targeted by collectors and can live beyond 40 years, meaning that individuals that reach adulthood could be reproductively active for decades. Hence, for yellow tang, the FRA scenario contrasts with that of many other protected areas, where adult targeted fish are caught upon spilling over the reserve boundary.
Because juveniles are strongly site-attached, their abundance in open areas is dependent on natural levels of settlement and not directly affected by spillover, says Jeremy Claisse of the University of Hawai`i at Manoa, a member of the research team. "A main benefit [of the FRAs] is that more of the coastline will have higher adult densities than would be the case if fishing were unconstrained," says Claisse. "Most of the yellow tang settlement in West Hawai`i will be of fishes/larvae that originated from that immediate area, hence local fishers will benefit if population fecundity is sustained or enhanced by reserves."
With the increasing exploitation of yellow tang, the juvenile population has declined in the open areas by as much as 45% since 1999. Because adults are not fished, the fishery will receive greater reproductive output for every unit area of juvenile habitat that is protected, says Claisse. "These protected areas will provide additional adult spawning stock to the available adult habitat in the surrounding open areas," he says.
Role of public support:
Brian Tissot of Washington State University also co-authored the Biological Conservation study and has been active with the FRAs since their planning. He says the successful designation of the network resulted from three factors, all related to public support in some way.
"First, we had strong community support for the FRAs due to long-standing conflicts in the community around aquarium collecting, and MPAs were seen as the best solution to the problem," he says. "Second, we had strong legislative support. A bill was passed that established a flexible management framework. That framework created FRAs along a minimum of 30% of the coastline and also involved the community in co-management with the state. Third, it was critical to create synergy among state managers and biologists, academic scientists, outreach specialists, and students to educate the public and get folks involved in supporting management solutions. In the end we had 93% support at the public hearing that established the FRAs."
Opponents of the FRA plan included the aquarium collectors, though. They said they had been assured that no more than 30% of the coastline would be no-take. Ten years later they remain skeptical. A survey in 2007 of 22 aquarium collectors indicated most are still frustrated with the FRAs: 68% said they were either "dissatisfied" or "strongly dissatisfied" with the protected areas. Asked if they felt the FRAs had helped enhance reef fish populations, 45% called the FRAs ineffective while 23% called them effective. The rest were neutral.
"The overall level of satisfaction that fishers have with the FRAs is poor," says Todd Stevenson of Washington State University, who conducted the survey. "And fisher perceptions of how well the FRAs have performed in enhancing reef fish populations are inadequate."
The value of "before" data:
Critical to research of the network has been the existence of data collected along the coast prior to designation of the FRAs. Those "before" data allow researchers to differentiate between changes due to designation and changes that may be due to other factors.
"It is obviously very important from an experimental design perspective to have a complete 'before-after control-impact' (BACI) design," says Tissot. [Editor's note: BACI design was described in our December 2003/January 2004 issue (MPA News 5:6).] "The BACI design is the best possible approach for analysis of MPAs and is a statistically powerful way to tease out detailed changes over time. We also had two sets of controls to compare to the FRAs: 1) long-term protected areas that had been closed for at least 10 years prior to FRA establishment; and 2) areas still open to aquarium collecting. This allowed us to look both at where we expected the FRAs to go and what happened outside the FRAs once they were closed.
"Not having 'before' data always opens the door to some uncertainty regarding effectiveness," Tissot continues, "although it can be addressed in a variety of ways and is not insurmountable. Now, with 10 years of data, I would say the 'before' data are becoming less important as we focus more on the long-term trends."
For more information:
Jeremy Claisse, Hawaii Cooperative Fishery Research Unit, Department of Zoology, University of Hawai`i at Manoa, Honolulu, Hawai`i, U.S. E-mail: [email protected]
Brian N. Tissot, School of Earth & Environmental Science, Washington State University, Vancouver, Washington, U.S. E-mail: [email protected]
Todd Stevenson, School of Earth & Environmental Science, Washington State University, Vancouver, Washington, U.S. E-mail: [email protected]
CASE 2 - WEST HAWAI`I: A network of reserves to replenish an aquarium fishery
In 1999 a multi-stakeholder working group on the west coast of the island of Hawai`i approved a proposal to designate a network of fishing closures (MPA News 1:1). The nine closures, called fish replenishment areas (FRAs), were intended primarily to address a long-standing user conflict between dive tour operators and aquarium fish collectors. In the FRAs, which covered approximately 35% of the 240-km West Hawai`i coastline, diving would be allowed and aquarium fish collecting would not.
Over the past 10 years, the network has helped reduce the level of conflict between the groups. But it has also had a clear effect on populations of the main target species for aquarium collectors - yellow tang. There is spillover of adult yellow tang occurring across the FRA boundaries, indicating the protected areas may play an important role in sustaining stocks over the long term.
Evidence of spillover:
In a paper published in the May 2009 issue of the journal Biological Conservation, a team of researchers showed that prior to designation of the FRA network, yellow tang densities were similar at sites open to fishing and those slated for closure. By 2007, however, the closed areas had five times the density of target-sized fish, and 48% higher density of adults than open areas. The main evidence of spillover was this: densities of adults in so-called "boundary" areas (open areas less than 1 km from nearest MPA boundary) were significantly higher than in open areas far from MPA boundaries.
In light of the fact that the number of active aquarium fishers along the coast doubled from 1999 to 2007, as did the total catch of yellow tang, the authors suggested that the protected areas could be essential for supplying adult fishes to keep the fishery going. "The West Hawai`i protected area network, by sustaining adult stocks over large areas of the coastline, acts as a bulwark against overexploitation," wrote the research team, which included government and academic scientists.
The yellow tang fishery is relatively unique, at least compared to most commercial food fisheries. The prime target size for yellow tangs is 5-10 cm; this is when they are usually less than two years old and still juvenile. Adults on the other hand are not targeted by collectors and can live beyond 40 years, meaning that individuals that reach adulthood could be reproductively active for decades. Hence, for yellow tang, the FRA scenario contrasts with that of many other protected areas, where adult targeted fish are caught upon spilling over the reserve boundary.
Because juveniles are strongly site-attached, their abundance in open areas is dependent on natural levels of settlement and not directly affected by spillover, says Jeremy Claisse of the University of Hawai`i at Manoa, a member of the research team. "A main benefit [of the FRAs] is that more of the coastline will have higher adult densities than would be the case if fishing were unconstrained," says Claisse. "Most of the yellow tang settlement in West Hawai`i will be of fishes/larvae that originated from that immediate area, hence local fishers will benefit if population fecundity is sustained or enhanced by reserves."
With the increasing exploitation of yellow tang, the juvenile population has declined in the open areas by as much as 45% since 1999. Because adults are not fished, the fishery will receive greater reproductive output for every unit area of juvenile habitat that is protected, says Claisse. "These protected areas will provide additional adult spawning stock to the available adult habitat in the surrounding open areas," he says.
Role of public support:
Brian Tissot of Washington State University also co-authored the Biological Conservation study and has been active with the FRAs since their planning. He says the successful designation of the network resulted from three factors, all related to public support in some way.
"First, we had strong community support for the FRAs due to long-standing conflicts in the community around aquarium collecting, and MPAs were seen as the best solution to the problem," he says. "Second, we had strong legislative support. A bill was passed that established a flexible management framework. That framework created FRAs along a minimum of 30% of the coastline and also involved the community in co-management with the state. Third, it was critical to create synergy among state managers and biologists, academic scientists, outreach specialists, and students to educate the public and get folks involved in supporting management solutions. In the end we had 93% support at the public hearing that established the FRAs."
Opponents of the FRA plan included the aquarium collectors, though. They said they had been assured that no more than 30% of the coastline would be no-take. Ten years later they remain skeptical. A survey in 2007 of 22 aquarium collectors indicated most are still frustrated with the FRAs: 68% said they were either "dissatisfied" or "strongly dissatisfied" with the protected areas. Asked if they felt the FRAs had helped enhance reef fish populations, 45% called the FRAs ineffective while 23% called them effective. The rest were neutral.
"The overall level of satisfaction that fishers have with the FRAs is poor," says Todd Stevenson of Washington State University, who conducted the survey. "And fisher perceptions of how well the FRAs have performed in enhancing reef fish populations are inadequate."
The value of "before" data:
Critical to research of the network has been the existence of data collected along the coast prior to designation of the FRAs. Those "before" data allow researchers to differentiate between changes due to designation and changes that may be due to other factors.
"It is obviously very important from an experimental design perspective to have a complete 'before-after control-impact' (BACI) design," says Tissot. [Editor's note: BACI design was described in our December 2003/January 2004 issue (MPA News 5:6).] "The BACI design is the best possible approach for analysis of MPAs and is a statistically powerful way to tease out detailed changes over time. We also had two sets of controls to compare to the FRAs: 1) long-term protected areas that had been closed for at least 10 years prior to FRA establishment; and 2) areas still open to aquarium collecting. This allowed us to look both at where we expected the FRAs to go and what happened outside the FRAs once they were closed.
"Not having 'before' data always opens the door to some uncertainty regarding effectiveness," Tissot continues, "although it can be addressed in a variety of ways and is not insurmountable. Now, with 10 years of data, I would say the 'before' data are becoming less important as we focus more on the long-term trends."
For more information:
Jeremy Claisse, Hawaii Cooperative Fishery Research Unit, Department of Zoology, University of Hawai`i at Manoa, Honolulu, Hawai`i, U.S. E-mail: [email protected]
Brian N. Tissot, School of Earth & Environmental Science, Washington State University, Vancouver, Washington, U.S. E-mail: [email protected]
Todd Stevenson, School of Earth & Environmental Science, Washington State University, Vancouver, Washington, U.S. E-mail: [email protected]
