Influence of Wind and Swelloncatch Rates in a Dive Fishery: A Case Study from the South Australian Abalone Fishery

“Fishing Smart”: Bioeconomic Optimization of Fishing Strategies in an Australian Mollusk Fishery

“…The latter is important because fishing opportunity is limited by weather (Stobart et al. 2016) and the extended period provides enough time for both TACCs to be harvested under favorable weather conditions. This information led the WZ to make changes to fishing practices, with most of the quota for both species voluntarily being harvested before September, including the implementation of restrictions on fishing greenlip early in the year (Stobart et al.…”

“…In response, the WZ is looking to aid stock recovery and return to the long‐term mean TACC, with the adoption of S1 for both species already widely implemented to reduce fishing mortality by leaving more abalone in the water each year for the given TACC. Although the long‐term benefits of S1 have not yet been demonstrably realized for blacklip, there is evidence that greenlip catch rates increased in 2015 and 2016 and that this increase was at least partially due to the change in fishing practice to fishing most of the greenlip quota in March–June (Stobart and Mayfield 2016). The 6‐month season proposed in Table 3 would lead to almost the equivalent of the entire annual catch from one blacklip license and two greenlip licenses being left in the water each year (i.e., 15,433 blacklip and 22,596 greenlip left unharvested per year).…”

Modelling trends including effects of natural disturbance in an abalone dive fishery in Australia

“…The Bayesian model fitted the data well and demonstrated that there was a high probability of decline in greenlip abalone stocks, which was particularly evident for Hospital Reef and the Julia Bank reef complex where most of the fishing occurred. CPUE often tends towards hyperstability, especially with sedentary mollusks such as abalone where divers are able to make spatial adjustments to their fishing patterns to maintain catch rates despite decreases in total biomass (Dowling et al., ; Kahui & Alexander, ; Stobart, Mayfield, & Carroll, ), a corollary being that the stock may be hyper‐depleting even when catch levels are maintained (Hilborn & Walters, ). In effect, the relationship between biomass and catch rate exhibits an asymptotic relationship (see Miller, ).…”

“…The potential for hyperdepletion in CPUE caused by weather effects of wind and swell is valid and has been investigated by Stobart et al. () for both greenlip and blacklip abalone in South Australia. Although their study revealed that swell height affected CPUE for blacklip abalone catches on shallow reefs, there was no evidence of hyperdepletion in greenlip abalone CPUE, largely because commercial divers avoided fishing during adverse weather.…”