An assessment of participation, catch and effort in the KwaZulu-Natal shore-based marine linefishery, with comments on management effectiveness

Abstract

The primary purpose of this study was to evaluate the effectiveness of current management of the KwaZulu-Natal (KZN) shore-based marine linefishery. Methods used included a stratified-random creel survey and an associated questionnaire survey. The study was undertaken between February 2009 and January 2010. Total participation ranged between 41 283 and 68 087 shore-anglers. Results show that there has been little change in participation in the KZN shore-fishery since 1994-1996. In contrast, total angler effort (779 382-843 702 angler-days y -1 ) has decreased substantially over the past 13 years. Overall catch per unit effort (CPUE) for the KZN shore-linefishery amounted to 0.18 ± 0.3 fish angler -1 h -1 or 0.07 ± 0.13 kg angler -1 h -1 . In all, 84 fish species, belonging to 39 families, were recorded in catches of shore-anglers during the study period. Only five species accounted for 75% of the catch recorded along the coast (Sarpa salpa 34.8%, Pomatomus saltatrix 14.7%, Diplodus capensis 14.5%, Pomadasys olivaceum 6.5% and Rhabdosargus holubi 4.9%). The total annual catch for the KZN shore-linefishery was estimated between 249.2 and 276.7 t y -1 (or 636 589-706 995 fish y -1 ). Analysis of overall CPUE, catch composition and total catch in the shore-based linefishery of KZN suggested that it is currently in a relatively stable condition and that little change has occurred over the past 13 years. However, comparisons of species-specific CPUE values from this study with recent literature suggest that some species (e.g. Argyrosomus japonicus) are severely overexploited. Over the past few decades there seems to have been a gradual transition in landings from long-lived, high trophiclevel, piscivorous fish (e.g. A. japonicus) to more short-lived, low trophic-level species (e.g. S. salpa). The results therefore suggest that present exploitation levels may not be sustainable for certain slow-growing, long-lived fish species. Current management regulations appear to have limited effectiveness based on poor angler compliance and knowledge of the regulations. In this regard, it is important to consider alternate management measures that may offer more effective protection to fish and at the same time be more easily understood by all anglers in the linefishery. Recommendations for improved management and the importance of the establishment of an effective MPA network are briefly discussed.

Traditional management strategies fail to arrest a decline in the catch‐per‐unit‐effort of an iconic marine recreational fishery species with evidence of hyperstability

“…However, as the knowledge of and the compliance with minimum size limits are low amongst South African shore anglers (Brouwer et al . ; Dunlop & Mann ), it is likely that slot size limits would be unsuccessful.…”

“…Daily bag or creel limits are also common in recreational fisheries. Unfortunately, although many recreational anglers do believe that bag limits are effective (Dunlop & Mann ), most fisheries managers do not share their enthusiasm (Radomski et al . ).…”

“…; Cowley et al . ; Dunlop & Mann , Dunlop & Mann ) has increased the motivation to break the regulations and has placed greater pressure on the L. amia stock.…”

“…Gwinn et al (2015), using general age-and size-structured population models on several recreationally important fish species, found that fisheries managed with harvest slot size limits, not only consistently produced greater numbers of fish, but also more trophy specimens. However, as the knowledge of and the compliance with minimum size limits are low amongst South African shore anglers (Brouwer et al 1997;Dunlop & Mann 2012), it is likely that slot size limits would be unsuccessful.…”

Movement patterns of surf-zone fish species in a subtropical marine protected area on the east coast of South Africa

“…Among the alternative approaches advocated is the development of more holistic management strategies, such as an ecosystem-based approach to management, and the establishment of no-take marine protected areas (MPAs) (Halpern et al 2010). Over the past 25 years, MPAs have increasingly been promoted to complement conventional fisheries management of surf-zone angling fish species in South Africa Attwood 1991, 1993;Attwood and Bennett 1994;Attwood et al 1997;Brouwer et al 1997;Cowley et al 2002;Mann et al 2003;Attwood and Cowley 2005;Götz et al 2008;Dunlop and Mann 2012;Venter and Mann 2012). This is because, on their own, the conventional fisheries management approaches of using daily bag limits, minimum size limits and closed seasons have been unable to arrest a decline in abundance of many important linefish species (Griffiths 2000;Mann 2013).…”