Trends in biomass of coral reef fishes, derived from shore-based creel surveys in Guam

Abstract

Coral reef fisheries have a cultural, economic, and ecological importance and sustain the societal well-being of many coastal communities. However, the complexities of the multigear, multispecies fisheries that target coral reef species pose challenges for fisheries management. We focus on the Guam shore-based coral reef fishery 1) to evaluate the characteristics of the past and recent fishery in terms of catch composition and effort per gear type and 2) to reconstruct the reef-fish population in shallow (depths ≤30 m) water during 1985-2012. To accomplish this, we used the results from a detailed creel survey conducted by the Guam Division of Aquatic and Wildlife Resources. The total estimated effort has stayed more or less stable; however, the estimated total catch has dropped from an annual mean of 100 metric tons (t) during the period 1985-1990 to 37 t during the period 2007-2012. Catch per unit of effort (CPUE) declined for most gear types between the 2 time periods. Reconstruction of historical targeted fish biomass, based on CPUE, showed a general decrease in biomass from 1985 to 2012. Biomass quickly dropped to about half of the 1985 values, then leveled off for a decade before declining again beginning in 2003 and continuing through 2012.