Size-specific survival and fishing mortality estimates for redabalone, Haliotis rufe-scens, using mark-recapture data

摘要

Estimates of size specific natural and fishing mortality are currently not available for red abalone, Haliotis rufescens, in northern California. We examined annual survivorship of three size classes (<100 mm, 100.1 to 178 mm, and >178 mm, the legal fishing limit) of red abalone using capture-mark-recapture data in northern. We estimate fishing mortality comparing fished and reserve sites in northern California. The number of tagged individuals (n = 273 to 2,145), survey occasions (n = 3 to 7), and size composition of individuals (41.5 to 227 mm, maximum shell length, MSL) were variable at each site. The annual survival probabilities of the smallest size class (<100 mm MSL) at one reserve site in northern California was 0.52 y super(-1) plus or minus (0.05 SE) and was 0.36 y super(-) plus or minus (0.07 SE) to 0.51 y super(-1) plus or minus (0.08 SE) in southern California. Annual survival of the mid-size class (100.1 to 178 mm MSL) from four sites at northern California ranged from 0.47 y super(-1) plus or minus (0.05 SE) to 0.71 y super(-1) plus or minus (0.04 SE). The largest size class (>178 mm MSL) had a large range of annual survivorship values of 0.26 y super(-1) plus or minus (0.06 SE) to 0.95 y super(-1) plus or minus (0.08 SE) in fished and reserve sites in northern California. Instantaneous fishing mortality (F) was estimated to be 0.68 to 1.29. This study is an example of how capture-mark-recapture data from fished and reserve sites and the selection of parsimonious models can be used to estimate natural and fishing mortality estimates.