Fisheries management and regulations

Abstract

As scientists have been documenting the decline of many shark populations (Manire and Gruber, 1990; Stevens et al., 2000; Baum et al., 2003; Ferretti et al., 2010; Clarke et al., 2013), it is now widely acknowledged that there is an urgent need to manage and regulate shark fisheries more effectively (FAO, 1999; Musick et al., 2000; Ward-Paige et al., 2012). Shark fisheries likely pre-date recorded history, but it is only over the last 50 years that shark catches have increased sharply and are now estimated conservatively at 1.4 million tonnes or 100 million individuals per year (Worm et al., 2013). Yet, due to sharks’ life history of slow growth, late maturity and limited reproduction, most species are intrinsically vulnerable to exploitation (Smith et al., 1998; Musick et al., 2000; Dulvy et al., 2008). Compounding this problem is the lack of spatial refuges due to the global expansion and industrialization of fishing (Watson et al., 2012). Today, the average annual exploitation rate of sharks is estimated to range from 6.4 per cent to 7.9 per cent of total biomass fished per year, which significantly exceeds the rebound rate of many species, averaging 4.9 per cent per year (Worm et al., 2013). Hence, it is unsurprising that shark populations have declined to a fraction of their former abundance, and that many continue to decline under current exploitation rates. There are 113 shark fishing nations, of which 20 collectively account for ~80 per cent of the global shark catch (Camhi et al., 2009); 13 of these are located in the tropics (Figure 14.1). The three highest shark-producing fishing areas for 2011 were the Western Central Pacific, Eastern Central and Southwest Atlantic (Figure 14.1). Shark fisheries around the world represent a complex management problem for a number of reasons: many shark stocks are shared by several countries; few stock assessments are available; and even accurate catch statistics are lacking from many areas (FAO, 2008). As a result, two independent studies estimated that actual catches of sharks may exceed catches reported to the United Nations Food and Agriculture Organisation (FAO) about four-fold (Clarke et al., 2006; Worm et al., 2013). Hence, total mortality is much larger than what is accounted for by official statistics.