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It is estimated that C. gibbiceps stocks have declined to between 1% and 5% of their historical values (Griffiths and Lamberth 2002). The population decline of this species would almost certainly have been greater during the 20th century had it not been for protected adults stocks on the offshore Agulhas Bank and Transkei (Griffiths 2000). Natural and fishing mortality rates are unknown for this species but evidence suggests that C. gibbiceps is heavily overexploited (Wilke and van Zyl 2012).
The trend in mean size for this species is currently unknown (Wilke and van Zyl 2012). A sex ratio of 1: 0.02: 1.56 (male: intersex: female) was reported from the Southeast Cape (C.D. Buxton, DIFS unpublished data in Wilke and van Zyl 2012) and 1: 0.02: 0.64 was reported (male: intersex: female) Agulhas Banks (M. van Zyl, UCT unpublished data in Wilke and van Zyl 2012).
Catch rates of C. gibbiceps declined consistently in the Southwestern Cape but peaked in the Southern Cape from 1927 to 1931 (Griffiths 2000). The mean catch per boat per year of C. gibbiceps in the Southwest Cape decreased from 196 kg (1897-1906) to 187 kg (1927-1931) and subsequently declined to 8 kg (1986-1998) revealing a decline in CPUE to 3.9% of the original catch rate. In the Southern Cape the mean catch per boat per year increased sharply from 70 kg (1897-1906) to 757 kg (1927-1931) and then declined dramatically to 7 kg with a decline in CPUE to only 0.91% of the original catch rate (1986-1998). Similarly, in the Southeast Cape the mean catch per boat per year increased from 96 kg (1897-1906) to 382 kg (1927-1931) and subsequently declined to 20 kg with CPUE only 5.35% of the original level (1986-1998). The CPUE for this species has therefore declined below the critical 25% level of abundance to <10% of historical values (Griffiths 2000).
The total reported catch for this species has declined from about 20 tonnes in 1986 to an average of 2 tonnes from 2001 to 2006. Using targeted effort data, there has been a gradual 28.5% decline in CPUE over the period from 1985 (0.35 kg/man/hr) to 2007 (0.25 kg/man/hr) (National Marine Linefish System unpublished data). Chrysoblehus gibbiceps dominated the landings at Simonstown, Kalk Bay, and Strand at the start of the 20th century at 85%, 60% and 46% respectively (Crawford and Crous 1982). In the 1960s and 1970s, C. gibbiceps was targeted by spearfisherman on deep, flat reefs from 15 to 20 m along the western coast of False Bay from March to August (Biden 1930, Wilke and van Zyl 2012). A decline in catch composition was also observed at Struisbaai between 1969 and 1980 (Crawford and Crous 1982).
Commercial data show that since 2000 commercial fishing effort has declined dramatically in the traditional linefishery from approximately 3,000 to 450 vessels in line with the long-term fisheries rights allocation process implemented in 2006 (Department of Agriculture, Forestry, and Fisheries 2012).
The daily bag limit for recreational fishers for C. gibbiceps is one fish per person per day and the minimum landing size is 30 cm TL. For commercial linefishers there is no bag limit but the minimum landing size is 30 cm TL (Department of Agriculture, Forestry and Fisheries 2012). Although C. gibbiceps is protected in a number of no-take MPAs over its entire distributional range including the De Hoop Marine Reserve, Goukamma, Tsitsikamma National Park, Sardinia Bay Reserve, and Bird Island (B. Mann and C. Buxton pers. comm. 2009, Wilke and van Zyl 2012) little protection is offered by MPAs to the adults of this species that occur offshore on the Agulhas Banks (Wilke and Griffiths 1999).
Additional restrictions that have been proposed include a strict commercial bag limit, an increase of the minimum landing size to 35 cm TL, and a two month closed season from December 1st to January 31st (van Zyl 2013).