Factors influencing the distribution of Kona crabs Ranina ranina (Brachyura: Raninidae) catch rates in the Main Hawaiian Islands

Abstract

A generalized linear model and commercial catch report data were used to describe spatial and temporal patterns in Kona crab, Ranina ranina Linnaeus, 1758, catch rates in the Main Hawaiian Islands. Three alternative hypotheses regarding factors influencing the temporal and spatial distribution of Kona crabs were evaluated using multi-model inference. Broad-scale island effects explain the spatial distribution of catch rates better than the finer-scale factors of depth and swell exposure. Interdecadal declines in catch rates were noted for islands with high human density, while other islands had stable or increasing catch rates. The interdecadal changes in catch rates may be explained by changes in population abundance and management-induced changes in fishing patterns in the recent period. Kona crab behaviors associated with the reproductive cycle contribute to seasonal variations in observed catch rates.