Quantifying fishing effort: a synthesis of current methods and their applications

Abstract

The need to accurately quantify fishing effort has increased in recent years as fisheries have expanded around the world and many fish stocks and non‐target species are threatened with collapse. Quantification methods vary greatly among fisheries, and to date there has not been a comprehensive review of these methods. Here we review existing approaches to quantify fishing effort in small‐scale, recreational, industrial, and illegal, unreported and unregulated (IUU) fisheries. We present the strengths and limitations of existing methods, identifying the most robust methods and the critical knowledge gaps that must be addressed to improve our ability to quantify and map fishing effort. Although identifying the ‘best’ method ultimately depends on the intended application of the data, in general, quantification methods that are based on information on gear use and spatial distribution offer the best approaches to representing fishing effort on a broad scale. Integrating fisher’s knowledge and involving fishers in data collection and management decisions may be the most effective way to improve data quality and accessibility.

Global patterns of marine mammal, seabird, and sea turtle bycatch reveal taxa-specific and cumulative megafauna hotspots

“…However, a detailed map of global fishing effort is needed to fully contextualize these interaction data. Information on the amount and spatial distribution of fishing effort is rarely reported, because fishing activity is typically reported as landed catch because of the relative ease of data collection at landing sites (54). Catch data provide information on the harvest of target species but do not represent fishing effort because of variable catchability in space and time.…”

Assessing Changes in Fisheries Using Fishers’ Knowledge to Generate Long Time Series of Catch Rates: a Case Study from the Red Sea

“…This is why fishery data collection is critical at both local and international levels (Garibaldi 2012). Most fishery data collection systems, however, emphasize industrial fisheries (McCluskey and Lewison 2008). Small-scale fisheries, which account for more than 95% of the world's fishers and are critical to the socioeconomic life of communities (Berkes et al 2001, Pauly 2006, Andrew et al 2007, do not, however, get the attention they deserve.…”

Remote electronic monitoring as a potential alternative to on-board observers in small-scale fisheries

“…Independent on-board observers have traditionally been used to monitor target catch (Alfaro-Cordova et al, 2017;Haigh et al, 2002;Mangel et al, 2013) and bycatch (Caretta et al, 2004;Gales et al, 1998;Rogan and Mackey, 2007) in fisheries, including some small-scale fisheries (Doherty et al, 2014;Mangel et al, 2010;Ortiz et al, 2016). However, use of on-board observers to quantify fishing activities can sometimes yield biased information, resulting from deployment effects (Benoît and Allard, 2009), observer effects (Benoît and Allard, 2009;Faunce and Barbeaux, 2011) and low fleet coverage (McCluskey and Lewison, 2008). Monitoring small-scale fisheries through observers poses a major challenge due to the large number of vessels, limited number of trained personnel, low enforcement and vigilance, and difficult working conditions, given the small size of vessels (Salas et al, 2007).…”