![]() ![]() I do so not to pre-emptively assess stock status based on catch data for either species complex or its component species. In this paper, I first describe each of the two fisheries in terms of gear type, catch selectivity and the types of fisheries-dependent data being collected, followed by a brief summary of catch data available for the two fisheries and a comprehensive summary of recently updated life-history data available for major species within each species complex. In Hawaii as elsewhere, parrotfishes generally inhabit shallow coral reef habitats at <30-m depths, and Deep-7 bottomfishes occur at mesophotic, 100–300 m depths of island slopes. A second consists of a seven-species bottomfish complex (the Deep-7: comprising six species of snappers and a single species of grouper). The first case involves a seven-species taxon of parrotfishes. These fisheries differ in their fundamental characteristics, in the consequences of managing by species complex and in the resolution of the difficulties involved in doing so. I herein describe two case studies from Hawaii of management using species complexes. However, catches need not be standardized by effort and CPUE need not be used as a proxy for abundance if direct estimates of stock biomass are available (e.g. Standardization using effort data for pooled species can be problematic (Kleiber & Maunder, 2008). These and other attributes of fisheries importantly influence appropriate management strategies. Whilst species are typically pooled within complexes as a default option, the population dynamic and ecosystem consequences of managing at the species-complex level potentially obscures the importance of recognizing ecologically dominant species, and poor understanding further introduces several inherent biases (Kleiber & Maunder, 2008).įisheries vary according to whether catch and landings are identified (or even identifiable) and recorded to species whether or not the gear used is selective for species and whether harvest data can be standardized by species-level effort (Maunder, 2001 Maunder & Punt, 2004). In these cases, a great many species are targeted for which few or no parameter estimates exist of key population traits like growth, reproductive maturity and the rates at which fundamental milestones such as maximum body size and age at maturity are attained (Medley, Gaudian, & Wells, 1993). ![]() The extraction of targeted resource species that are pooled within species complexes is typical in data-poor capture fisheries such as tropical reef fish fisheries of small island nations and when initially developing multispecies fisheries. ‘Species complexes’ are often used to characterize fisheries for which insufficient data exist on the biology of component species, the fishery itself or on both (Gulland, 1983). Ultimately, complexes of resource species need to be evaluated and managed based on many, sometimes conflicting and sometimes reinforcing, but always careful considerations such as those contrasted herein between the parrotfishes and bottomfishes of Hawaii. Assessments that recognize and quantify the ecosystem importance of habitat engineers and other ecological dominants could substantively improve management of species complexes. Pooling species is especially problematic when the ecosystem effects of extracting functionally dominant species should be an important management consideration in addition to that of species demographics. These data clearly indicate that, although pooling species is a tempting default option in data-poor situations, it is at best a necessary evil to be avoided when sufficient data on the demographics of component species become available. Species in the parrotfish taxon exhibit fast to very fast growth and short to moderate longevities, whilst Deep-7 bottomfishes exhibit moderate to very slow growth and long to very long lifespans. Recent research on key vital rates (growth, reproduction) for major species in both taxa indicates that these complexes consist of species with disparate life histories. These include seven species of parrotfishes (Scarinae, Labridae) and a seven-species ‘bottomfish’ complex (the ‘Deep-7’: comprising six species of snappers and a single species of grouper ). Current fisheries management includes many species complexes in Hawaii, this includes two taxa of species pooled at subfamily and higher levels. Surprisingly little published information exists on the pros and cons of managing extracted resources that are pooled as compound taxa such as species complexes. ![]()
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