Changes in frigate tuna populations on the south coast of Sri Lanka: evidence of the shifting baseline syndrome from analysis of fisher observations

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cg.contributor.affiliationInternational Water Management Instituteen
cg.coverage.countrySri Lanka
cg.coverage.iso3166-alpha2LK
cg.coverage.regionSouth-eastern Asia
cg.coverage.regionSouthern Asia
cg.identifier.doihttps://doi.org/10.1002/aqc.1068en
cg.issn1052-7613en
cg.issn1099-0755en
cg.issue2en
cg.journalAquatic Conservation: Marine and Freshwater Ecosystemsen
cg.volume20en
dc.contributor.authorVenkatachalam, A.J.en
dc.contributor.authorPrice, A.R.G.en
dc.contributor.authorChandrasekara, S.en
dc.contributor.authorSenaratna Sellamuttu, Sonalien
dc.contributor.authorKaler, J.en
dc.date.accessioned2014-06-13T14:47:53Zen
dc.date.available2014-06-13T14:47:53Zen
dc.identifier.urihttps://hdl.handle.net/10568/40548
dc.titleChanges in frigate tuna populations on the south coast of Sri Lanka: evidence of the shifting baseline syndrome from analysis of fisher observationsen
dcterms.abstractThis study examines changes in frigate tuna populations in southern Sri Lanka, based on reports from fishers in three age classes. Significantly higher values for best day's catch and largest specimen ever caught were obtained by older fishers than younger ones. Values were also significantly higher during early years, providing clear evidence of a decrease in the resource over time (1951-2007). Older fishers reported best catches further inshore and in shallower waters which, on becoming depleted, forced younger generations to fish in less exploited areas further offshore. Heavy harvesting is also evident from the significantly greater number of sites reported by older fishers as being depleted, compared with observations of younger fishers. These findings contrast markedly with catch and catch per effort patterns from statistics for frigate tuna and bullet tuna (combined) in southern Sri Lanka (1994-2004). No stock decline is evident, and at least one report in the early 1990s advocated increasing exploitation rates by 40% to maximize yields. Although not a primary research objective, fisher observations on frigate tuna populations were also analysed to help evaluate possible effects of the 2004 tsunami. Most fishers reported post-tsunami decline, but mainly from a larger new generation of fishers, rather than extra boats provided by aid money or (direct or indirect) biophysical impacts from the tsunami. Reliance on fishery statistics, especially for mixed species and over a limited period, can be risky and easily mask true stock status. Evidence of harvesting effects on frigate tuna in southern Sri Lanka is evident using questionnaire data over a longer time scale. This study provides another compelling case of the 'shifting baseline syndrome', whereby fishers of different ages have altered perceptions/experiences of their environment. This may be its first reported occurrence in Sri Lanka. Traditional knowledge from this and similar surveys may provide national fishery management with valuable insights and help improve conservation prospects for frigate tuna and other marine resources.en
dcterms.accessRightsLimited Access
dcterms.available2009-09-09
dcterms.bibliographicCitationVenkatachalam, A. J.; Price, A. R. G.; Chandrasekara, S.; Senaratna Sellamuttu, Sonali; Kaler, J. 2010. Changes in frigate tuna populations on the south coast of Sri Lanka: evidence of the shifting baseline syndrome from analysis of fisher observations. Aquatic Conservation: Marine and Freshwater Ecosystems, 20:167-176. doi: https://doi.org/10.1002/aqc.1068en
dcterms.extentpp. 167-176en
dcterms.issued2010-03
dcterms.languageen
dcterms.licenseCopyrighted; all rights reserved
dcterms.publisherWileyen
dcterms.subjectfisheriesen
dcterms.subjecttunaen
dcterms.subjecttsunamisen
dcterms.subjectsurveysen
dcterms.subjectecologyen
dcterms.typeJournal Article

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