Abstract
The catch efficiency of towed fishing gears is the fraction of the target species in the gear path that were caught and retained. Catch efficiency is fundamental for calculating population status required for establishing fisheries management reference points. Consequently, catch efficiency has been estimated for many commercially important scallop (Pectinid) fisheries. This article synthesizes and discusses estimates of catch efficiency of towed gears used to target scallops, the methods for estimating catch efficiency and the factors that influence these estimates. There exists considerable variation in catch efficiency estimates among studies (0.1 to 0.7), and it is important that this variation is accounted for during surveys and stock assessments to avoid erroneous advice and estimates. The high variation was driven by differences in experimental conditions, estimation methods and scallop behavior. Scallop size and substrate type were the two most common reporting categories discussed in the studies and consequently should be considered the two most important drivers of catch efficiency. Other important factors such as gear specifications, and scallop species were featured in some studies. This review will be highly useful for designing catch efficiency experiments, survey design and stock assessments by understanding, and accounting for, catch efficiency variation.