Perspectives of co-existence of wild and hatchery chum ... · wild population sizes of chum salmon...
Transcript of Perspectives of co-existence of wild and hatchery chum ... · wild population sizes of chum salmon...
Perspectives of co-existence of wild and hatchery chum salmon for
sustainable fisheries in Hokkaido, Japan based on ecosystem and autonomous management
Mitsuhiro Nagata
Salmon and Freshwater Fisheries Research Institute, Hokkaido Research Organization and Salmon Science Society
Chum salmon have remarkably increased thanks to improvement of hatchery techniques and better ocean conditions since 1970s (Kaeriyama, 1999). But
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Chum economical yields decreased dramatically from mid 1990s to early 2000s with increase in catch (Fig.1), becauseof too many catches causing extreme price down (Fig.2).
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Catch ( x 1,000 tons)Fig.2 The relationship between commercial catch and price in chum salmon fishery.
Fig.1 Annual changes in commercial catch and economical yield of Hokkaido chum salmon from 1980 to 2003.
Recovery of economical yield since 2004 > The HFFCA (Hokkaido Gyoren) exporting the extra fish to Europe and North America via China market. > Exports contributing to recovery of price and yield.
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Alaskan MSC-certified salmon joining the China market.
the TAB of MSC >>> Hokkaido chum set net fishery has nosufficient evidences for the wild salmon management.
Before entering full-assessment of MSC, Hokkaido fishery focuses on not only hatchery-based management but also wild salmon management.
the HFFCA (Hokkaido Gyoren) >>>> challenging MSC certification for Hokkaido chum salmon set net fishery.
Wild salmon policy and management Different management system between Japan and North America
1.Hokkaido Government >>>> Wild Salmon Policy 2.Kitami SEP association >>>> Wild Chum Salmon Management Plan in cooperation with local Fisheries Cooperative Associations (FCA).
10 local FCAs in the Kitami Region >> Autonomous Management in coastal fisheries (Bottom Up Control) >> Fishers of each FCA in the local community >> Strong protection : illegal and over-fishing destroy their fishery and community.
Board of DirectorsPresidents of 10 FC As, Deputy mayors, Executive director
Steering CommitteePresidents of 10 FC As, Directors of set net fisheries of 10 FS As
Advisory CommitteeHokkaido Government, HSFFRI, HNFRI,
Fishing Coordination Commission*information of catch and escapement data*recommendation of fishing regulation
Management system by Kitami SEP association
Salmon set net fishery
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Results of wild salmon counting in the Kitami region of 2010
7Unpublished data from Dr. Urabe et al. of SFFRI
● No-hatchery (Wild salmon river)● Hatchery without brood stock collection● Hatchery with brood stock collection
Final Principle Scores of MSC assessment of Hokkaido chum salmon set net fishery
Principle 1 - Target species < 80 ptsPrinciple 2 - Ecosystem > 80 ptsPrinciple 3 - Management > 80 pts
Over 80 pts are required to pass.
Main reasons for low score at PL1
1. Small population size of wild chum salmon and in shortage of recovery plan.
2. Insufficient data on straying of hatchery salmon
3. Insufficient practice on the segregation of hatchery salmon from wild populations to conserve wild salmon.
River Population size
No. of otolith‐marked fish*
% of marked fish *2
Estimated of total number of stray fish
Rusha 15 1 6.7% 13
Iwaobetsu 186 0 0% 0
Horobetsu 125 4 3.2% 38
Nukamappu 484 4 0.8% 38
Mokoto 448 1 0.2% 38
Sarobetsu 217 3 1.4% 38
Mobetsu 662 18 2.7% 34
Oumu 113 2 1.8% 30
Otoineppu 50 1 2.0% 25
Population size of natural spawners and straying of hatchery chum salmon in the Kitami region(2010)*1
No-hatchery (Wild salmon river)Hatchery without brood stock collectionHatchery with brood stock collection*2Marked fish is originated from the Shari River where is enhanced
Ne (effective population size) will be > 500 (FAO/UNEP 1981)
*1 Unpublished data from Dr. Urabe et al. of SFFRI
MSC CB >> Main action plan to improve
1.To increase natural spawning habitats and wild population sizes of chum salmon in the Kitami region because of less habitat and wild salmon. 2.To segregate hatchery programs from wild population to conserve wild salmon and to avoid negative impact of hatchery program such as reduction of genetic diversity and fitness, and expanding fish disease.
But, not easy to implement these plans!
Many man-made constructions such as dams, channelization, irrigation in Hokkaido, differing from Alaska.
Not easy to restore salmon habitats because too many private and government sectors involved in river and watershed management and construction.
Therefore, we have to restore the salmon habitats very slowly in negotiation and agreement with such sectors.
Different natural and human factors*Hokkaido >>>Human Population:5.5 million (9 x Alaska),Land Area: 83,000 km2 (5% of Alaska)*Alaska >>>Human Population: 0.6 million, Land Area: 1,720,000 km2
Expanding natural spawning by improvement of obstacles
Red circles showing redds (nests) by chum salmon (Unpublished data from SFFRI)
Old fish ladder did no work well because of too rapid velocity (Yabe et al.,1995).New fish ladder was installed in 2001. As the results, many chum salmon came up and spawned naturally. This improvement contributes to increasing population size.
Spawners
New fish ladder
Upstream
Movement of weir’s site to upstream
Hatchery
Weir
Improvement of holding box in the weir
Shari River Kitada (2014, Fisheries Science)
Escapement window
Improvement programs of coexistence of wild and hatchery chum salmon in Hokkaido
Wild salmon1. Accumulation of scientific data such as
population dynamics, genetic trait, carrying capacity of spawning and habitat in the enhanced and non-enhanced rivers
2. Estimation of escapement goal, management unit based on GSU, restoration of river environments to meet capacity considering human activity
Improvement programs of coexistence of wild and hatchery chum salmon in Hokkaido
Hatchery salmon1. Accumulation of scientific data such as
straying rate and gene flow by mass marking
2. Evidence of reduction of genetic diversity and fitness by hatchery programs of chum salmon ? >>> Controversial issues between Japanese and North-American scientists in MSC assessment and scientific review
High survival rate of chum salmon in the Kitami Region of Hokkaido (Kitada, 2014), suggesting >> No evidence of fitness reduction by hatchery activities.
>>> Too much precautionary approach causes the shrink of sound commercial fishery. So, withdrawal from MSC!
Do hatchery activities reduce fitness?Hatchery steelhead trout >>> Reduction of RRS (relativereproductive success) to wild fish (Araki et al. 2007)Hatchery chum salmon >>> No reduction of RRS (Berejikian etal., 2009)
Negative impact of hatchery depending on species ; >>> Steelhead juveniles spend more than two years in freshwater before seaward migration. Chum juveniles go to the sea soon after they swim up. >>> Reduction of fitness of steelhead trout may be easily caused by selection and hurry-up growth in hatchery.
So, we are very expecting FIP programs and O2 to resolve large
gaps between Japan and North American
Perspectives of co-existence of wild and hatchery chum salmon for sustainable fisheries in Hokkaido,
Japan based on ecosystem and autonomous management