Systematic review and meta-analysis of studies testing the efficacy of shark-bite mitigation

1. The development and scientific testing of shark-bite mitigation measures are increasing, but unstandardised testing impedes our ability to compare their efficacy.

2. We did a systematic review and meta-analysis to summarise efficacy using qualitative and quantitative approaches.

3. We reviewed 67 papers testing 114 measures across three mitigation types (area/personal/injury reduction). Measures to protect areas were the most tested (n = 64), followed by personal deterrents (n = 29). Effectiveness (based on vote-counting analysis) and mean Hedges’ g were similar across mitigation types, but personal measures, especially electric deterrents, had the highest variation and magnitude of effect sizes. Personal deterrent studies were all manipulative and provided the ability to test reduction in simulated bites, whereas area protection studies were often mensurative (70 %) and mostly measured shark abundance.

4. We recommend that future studies use the highest inference type as is reasonably practical (i.e., reduction in actual or simulated shark bites rather than differences in shark abundance). As the number of shark bites and the period over which mitigation measures have been implemented increase, so will opportunities to test the effectiveness of area protection quantitatively using high-inference metrics.

5. Our findings should encourage discussions among policy makers, water users, and conservationists to test measures with robust, quantitative assessments to reduce shark-bite risk.