Population trend
Trend
No stock assessments have been conducted for Polysteganus coeruleopunctatus; however, declines in catch per unit effort (CPUE) and catch composition indicate that this species may be over-fished in some areas, despite the increasing trend of fishing in deeper water in South Africa and Mozambique (Fennessy and Mann 2013). Contribution by weight to commercial linefish catches in KwaZulu-Natal increased from 2.9 % in 1986 to 5% in 1996 (S. Fennessy, ORI unpublished data). However, subsequently commercial catch composition in KwaZulu-Natal declined from the period 1994–1996 (3.6% by number and 3.4% by weight) to 2008–2009 (0.19% by number and 0.51% by weight) (Mann et al. 1997, Dunlop 2011).Targeted CPUE declined from 1.6 kg/man/hour to 1.2 kg/man/hour from 1985 to 2007 (NMLS unpublished data). In South Africa, the total commercial catch for this species peaked in 1992 at around 60 tonnes and declined steadily until 2003 where it has remained stable at around eight tonnes.
Commercial data show that since 2000 commercial fishing effort has declined dramatically in the South African linefishery from approximately 3,000 to 450 vessels as part of the long-term fisheries rights allocation process implemented in 2006 (Department of Agriculture, Forestry and Fisheries 2012).
In southern Mozambique, the species is now the dominant contributor to the semi-industrial linefishery, which has experienced marked declines in CPUE, resulting in some of the fleet moving northward to the Sofala area in central Mozambique, where this species dominates catches (Fennessy et al. 2012, Mutombene 2013). A recent assessment of the southern Mozambique population suggests that it is optimally exploited, and that no increase in fishing effort be allowed (Mutombene 2013).
Conservation
In South Africa, there are no species-specific conservation measures for P. coeruleopuctatus but it is included in the overall daily bag limit of ten fish per person per day for recreational anglers (Department of Agriculture, Forestry and Fisheries 2012). It is likely that P. coeruleopunctatus receives some protection in the Pondoland, St Lucia and Maputaland marine protected areas (MPAs) (Chater et al. 1993, Mann et al. 2006, Sink et al. 2006), and to some extent in the Ponta do Ouro Partial MPA in Mozambique (S. Fennessy, pers. comm.).
Stricter conventional fishery regulations should be considered for P. coeruleopuctatus, such as a commercial bag limit. Additional MPAs are also recommended as the deep reefs in the northern part of the KwaZulu-Natal Bight are likely to be prime habitats for this species (Fennessy and Mann 2013).
