Hyperstability masks declines in bumphead parrotfish (Bolbometopon muricatum) populations

CORAL REEFS
2016
Hamilton, Richard J.; Almany, Glenn R.; Stevens, Don; Bode, Michael; Pita, John; Peterson, Nate A.; Choat, J. Howard
Publisher N/A
SourceWeb of Science
Volume / Issue35 / 3
Pages751 - 763
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ISBN N/A
DOI10.1007/s00338-016-1441-0
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Conference Date N/A
Publication Date16-Sep
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AbstractBolbometopon muricatum, the largest species of parrotfish, is a functionally important species that is characterised by the formation of aggregations for foraging, reproductive, and sleeping behaviours. Aggregations are restricted to shallow reef habitats, the locations of which are often known to local fishers. Bolbometopon muricatum fisheries are therefore vulnerable to overfishing and are likely to exhibit hyperstability, the maintenance of high catch per unit effort (CPUE) while population abundance declines. In this study, we provide a clear demonstration of hyperstable dynamics in a commercial B. muricatum fishery in Isabel Province, Solomon Islands. Initially, we used participatory mapping to demarcate the Kia fishing grounds into nine zones that had experienced different historic levels of fishing pressure. We then conducted comprehensive underwater visual census (UVC) and CPUE surveys across these zones over a 21-month period in 2012_2013. The individual sites for replicate UVC surveys were selected using a generalised random tessellation stratified variable probability design, while CPUE surveys involved trained provincial fisheries officers and local spearfishers. A comparison of fishery-independent abundance data and fishery-dependent CPUE data indicate extreme hyperstability, with CPUE maintained as B. muricatum abundance declines towards zero. Hyperstability may explain the sudden collapses of many B. muricatum spear fisheries across the Pacific and highlights the limitations of using data-poor fisheries assessment methods to evaluate the status of commercially valuable coral reef fishes that form predicable aggregations.
Created: 12/14/2017 10:30 AM (ET)
Modified: 12/14/2017 10:30 AM (ET)
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