Spatial characterisation of Demersal Scalefish diversity based on recreational fishing data

Information on fish species diversity is important to monitor changes and maintain sustainability in multispecies fisheries. However, examination of species diversity often ignores spatial patterns, yet it is influenced by spatially structured ecological processes. Such information is important for identifying areas of high conservation value for individual species, taxonomic groups or the entire ecosystem. In this study, the spatial distribution of West Coast demersal scalefish diversity in Western Australia was characterized based on recreational fishing data collected through two off-site phone-diary surveys. Using multivariate indicator cokriging, the effect of fishing effort and measurement uncertainty was considered in the characterisation. The study found that teleost species from Families Epinephelidae, Glaucosomatidae and Sparidae were the most common, with the relative contribution of 77% and 71% to the total catch in 2011/12 and 2013/14, respectively. In addition, maps of diversity indices showed that high diversity was located at the south-central parts of the study area and increased near the coast with some patchiness at the southern part. Spatial maps can be helpful when site-specific management is aimed at maintaining a certain level of species diversity caught by recreational fishers.