Does unreported catch lead to overfishing?

Abstract

Catches are commonly misreported in many fisheries worldwide, resulting in inaccurate data that hinder our ability to assess population status and manage fisheries sustainably. Under‐reported catch is generally perceived to lead to overfishing, and hence, catch reconstructions are increasingly used to account for sectors that may be unreliably reported, including illegal harvest, recreational and subsistence fisheries, and discards. However, improved monitoring and/or catch reconstructions only aid in the first step of a fisheries management plan: collecting data to make inferences on stock status. Misreported catch impacts estimates of population parameters, which in turn influences management decisions, but the pattern and degree of these impacts are not necessarily intuitive. We conducted a simulation study to test the effect of different patterns of catch misreporting on estimated fishery status and recommended catches. If, for example, 50% of all fishery catches are consistently unreported, estimates of population size and sustainable yield will be 50% lower, but estimates of current exploitation rate and fishery status will be unbiased. As a result, constant under‐ or over‐reporting of catches results in recommended catches that are sustainable. However, when there are trends in catch reporting over time, the estimates of important parameters are inaccurate, generally leading to underutilization when reporting rates improve, and overfishing when reporting rates degrade. Thus, while quantifying total catch is necessary for understanding the impact of fisheries on businesses, communities and ecosystems, detecting trends in reporting rates is more important for estimating fishery status and setting sustainable catches into the future.

Community biomass and life history benchmarks for coral reef fisheries

“…Rates of recovery have been shown to vary with a number of factors but most importantly the effectiveness and size of fishing closures (McClanahan & Graham, ). The empirical values used here of 0.23 ± 0.16 (95% CI) were, however, close to mean values of 0.20–0.25 commonly used in fisheries modelling studies (Little & Grafton, ; Rudd & Branch, ). Nevertheless, empirical studies of recovery indicate high variation that is seldom well understood or modelled when estimating yields.…”

Cross-Matching VIIRS Boat Detections with Vessel Monitoring System Tracks in Indonesia

“…Further development of this study can be used to estimate unreported catch and improve stock assessments as well as other related information relevant for decision makers. Moreover, improved monitoring programs can benefit the assessment of efficient harvest strategies through improved estimates of maximum sustainable yield (MSY), biomass and carrying capacity of the fishery [45]; while the problems with catch under-reporting appear to be particularly serious in Indonesia, especially for catches of tuna and tuna like species [46].…”

Marine seafood production via intense exploitation and cultivation in China: Costs, benefits, and risks

“…the state of the fishery with respect to optimal fishing effort and biomass levels) is an oft-used indicator of fishery performance. Inferences drawn on the 'status' of resources will remain unbiased even if the magnitude of catches are biased, provided the trends in the data are correct [39]. Based on observed relationships between catch and effort, the inferred levels of optimal effort reported in this analysis are similar regardless of whether the SAU data or the Chinese data are used (Fig 3).…”