|Scientific Name:||Chrysoblephus laticeps (Valenciennes, 1830)|
Chrysophrys algoensis Castelnau, 1861
Chrysophrys laticeps Valenciennes, 1830
Chrysophrys pugicephalus Gilchrist & Thompson, 1909
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Mann, B.Q., Buxton, C.D. & Carpenter, K.E.|
|Reviewer(s):||Russell, B. & Pollard, D.|
|Contributor(s):||Gorman, C. & Comeros-Raynal, M.|
Chrysoblephus laticeps is a reef-dwelling, commercially important sparid with its core distribution along the South African coast, extending from False Bay to the Kei River. This species is considered severely overexploited throughout its range with a stock assessment in 2000 considering the stocks to be collapsed. However, it has been documented to occur at high densities in several MPAs, most notably in the Tsitsikamma National Park and the Goukamma MPA. This species exhibits life history attributes that typically confer higher vulnerability to extrinsic threats (e.g., sedentary and philopatric nature, slow growth, late maturation, longevity, and protogynous hermaphrotism). Though there have been considerable declines in population sizes throughout its range, conservation measures in places such as no-take MPAs have proven effective in the recovery of this species given its residency and small home range. Indeed, some studies have shown that even small MPAs (six km2) can offer effective protection for resident species such as the Roman Seabream. Despite an overall decline in total commercial line-fishery catch, C. laticeps CPUE has remained relatively stable between 1985-2007. In addition, CPUE has been stable in the centre of the Tsitsikamma MPA between 2006-2011, in the vicinity of the Goukamma MPA, CPUE increased after MPA implementation in 1990 and doubled the pre-reserve rate after 10 years. Furthermore, drastic nation-wide cuts in commercial effort have been implemented since 2003 to rebuild depleted line-fish stocks. Roman is a highly-valued species with inherent attributes that predispose it to higher extinction risk. Although no-take MPAs in the Eastern and Western Cape have been shown to be extremely effective in protecting this species, some illegal fishing still occurs within these protected areas which could significantly impact their function, specifically the Goukamma MPA. The Goukamma MPA was established in order to protect important offshore reef habitats used by commercially important sparids, such as C. laticeps, and protects a spawning population of this species. Chrysoblephus laticeps displays significantly lower abundance and size at exploited sites when compared to protected areas in its range and since this species exhibits a high degree of residency, post recruit ‘spill-over’ is quite limited. Due to this, the non-compliance in no-take MPAs poses a major threat. This species is conservation dependent as a result of its high degree of residency and habitat specificity. It is therefore listed as Near Threatened given its reliance on the effectiveness of MPAs and management measures in its range. In the absence or non-compliance of these conservation measures, or the failure of these actions to sustain and protect the species, C. laticeps may qualify for listing for one of the threatened categories in five years. We highly recommend that a rigorous stock assessment take place to confirm the effects of rebuilding and conservation effort on this species. If stocks outside MPAs show signs of recovery, this species may warrant listing as Least Concern although the present evidence suggests that it is currently conservation dependent.
|Range Description:||Chrysoblephus laticeps is endemic to southern Africa and is distributed from Namibia to Port St. John's, Eastern Cape, South Africa to 100 m depth; however, its occurrence is very rare on the west coast. The core distribution extends from False Bay in the west to the Kei River in the southeast (Griffiths and Wilke 2002). Records from southern Madagascar and Mauritius are doubtful (Fischer and Bianchi 1984, Smith and Heemstra 1991, Buxton 1987, van der Elst 1993, Heemstra and Heemstra 2004).|
|FAO Marine Fishing Areas:|
Atlantic – southeast; Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The C. laticeps population off South Africa is considered to be over-exploited with spawning biomass per recruit (SBPR) ~31% in 1986 in an exploited population off Port Elizabeth (Buxton 1992, 1993). The population has been depleted to varying degrees throughout its range with minimum of about 5% of historical abundance in many areas (Griffiths 2000). Stocks <25% of their pristine level are indicative severe of stock depletion in long lived species with a high risk of collapse (Clark 1991, Mace and Sissenwine 1993, Thompson 1993, Mace 1994). The mean catch per boat per year of C. laticeps in the Southwestern Cape increased from 425 kg (1897-1906) to 560 kg (1927-1931) but subsequently declined to 71 kg for the period 1986 to 1998 indicating a decline in CPUE to 12.65% of the highest recorded catch rates. Similarly in the Southern Cape, mean catch per boat per year increased from 132 kg (1897-1906) to 229 kg (1927-1931) but then declined dramatically to 40 kg in the period 1986 to 1998 indicating a decline in CPUE to 17.44%. In the Southeastern Cape, the mean catch per boat per year decreased from 860 kg (1897-1906) to 558 kg (1927-1931) and continued to decrease to 40 kg (1986-1998) with a decline in CPUE to 4.65% (Griffiths 2000). Although there has been a continued decline in total commercial catches from 1985–2007, CPUE has remained relatively stable over this period (National Marine Linefish System unpublished data).|
Chrysoblephus laticeps is thus considered to be severely overexploited throughout its range (Griffiths 2000) but it still occurs at high densities in several MPAs, most notably in the Tsitsikamma National Park and Goukamma MPA (Buxton 1987, Buxton and Smale 1989, Götz 2005, Götz et al. 2008b, Kerwath et al. 2013a). This species was found at higher densities within the protected part of the Goukamma MPA, as defined by Götz (2005), with a CPUE of 4.3 fish/angler/hour and an underwater visual census (UVC) of 2.2 fish/point-count compared to that of exploited areas with a CPUE of 3.4 fish/angler/hour and UVC of 1.8 fish/point-count. The condition factor of this species in the protected area, however, was significantly lower than that of the individuals in exploited areas and it is suspected to be due to greater intra-specific competition within the MPA (Götz 2005).
After the establishment of the Goukamma MPA in 1990, the CPUE adjacent to the MPA (within 30 km of the MPA boundary) improved, doubling the pre-reserve rate after 10 years (Kerwath et al. 2013a). Diving and angling surveys in several MPAs, including Goukamma, indicate that this species responds well to spatial protection, and abundance, size-structure, sex-ratio, and age-at-sex-change have recovered inside reserves of various sizes (Buxton 1989, 1993; Götz 2005; Kerwath et al. 2013a).
Sex ratios are skewed towards females in exploited areas compared to populations in protected areas (Buxton 1993) as a result of the protogynous hermaphroditism exhibited by C. laticeps. Exploited populations of C. laticeps have a lower age-at-maturity and age-at sex-change compared to protected populations inside MPAs (Buxton 1993, Götz 2005). However, in areas of low to moderate fishing pressure an even sex ratio can be maintained through a shift in size/age-at sex-change (Götz et al. 2008a). In terms of genetics, C. laticeps occurs in a single, well-mixed population (Teske et al. 2010).
Fishing mortality reported from an exploited area off Port Elizabeth in the Southeastern Cape was estimated at 0.29 per year (M=0.11 per year) while in the Tsitsikamma MPA over the same period (1980-86) the fishing mortality was reported to be 0.047 per year (M=0.19 per year) (Buxton 1992). A more recent per-recruit stock assessment in the exploited area adjacent to the Goukamma MPA found that the roman population was optimally exploited at 52% of its pristine spawner biomass (Götz 2005) but fishing pressure near metropolitan areas is probably considerably higher than this (Buxton 1992).
Commercial data show that since 2000 commercial fishing effort has declined dramatically in the South African 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).
|Current Population Trend:||Stable|
|Habitat and Ecology:||Chrysoblephus laticeps adults inhabit deep, high-profile, inshore and offshore reefs to 100 m (Buxton and Smale 1984, Buxton 1987, Götz 2005, Götz et al. 2008b) while juveniles use shallow subtidal reefs to 30 m as nursery areas (Penrith 1972a, Buxton and Smale 1984, Buxton 1987, Beckley and Buxton 1989). This species is a benthic carnivore that feeds on a wide variety of reef associated invertebrates. Adults primarily prey on echinoderms and cephalopods as well as some crustaceans and polychaetes while the diet of juveniles mainly consists of polychaetes and some small-bodied decapods and mysids (Buxton 1984, Buxton 1987). Adults are mainly resident within small home ranges of <100 m linear extent, but a few individuals (~9%) travel distances over two magnitudes larger than the home range. These movements are rapid, inconsistent in direction and independent of sex, size, and fish density (Kerwath et al. 2007a, 2007b). |
This species is the only abundant reef-dependent teleost in this feeding category in False Bay, South Africa (Lecanteur and Griffiths 2003). Extensive tagging results have shown that C. laticeps is an extremely resident species and has a small home range (Buxton and Allen 1989, Buxton and Smale 1989, Kerwath et al. 2007a, 2007b). Chrysopblephus laticeps is a weak swimmer and becomes hydrodynamically poorer as it increases in size (Penrith 1972a).
The maximum length recorded for C. laticeps is 51.2 cm FL (Buxton 1987), the maximum weight is 4.57 kg (SAUFF 2012) and the maximum age is 19 years (male) (Götz 2005).
Chrysoblephus laticeps a protogynous hermaphrodite and change of sex occurs between seven and nine years of age and 27 cm to 30 cm length, with all individuals over 33 cm being functional males (Penrith 1972a, Buxton 1992, van der Elst 1993, Teske et al. 2010, Götz et al. 2013). After sex change takes place, the behaviour of this species also changes. As females, C. laticeps participates in social open-reef behaviours but becomes solitary, cave dwelling, and territorial as a male (van der Elst 1993). Males occupy territories and will mate with several females (Buxton 1989, Buxton 1990). Chrysoblephus laticeps is a pair and broadcast spawner, releasing its gametes above the substratum after an elaborate court ship routine (Buxton 1990, Kerwath et al 2013a). Chrysoblephus laticeps spawns throughout its range and lays pelagic eggs. Larvae are passively transported and post-flexion larvae settle after ~17 days (Teske et al. 2010).
The spawning season extends from October to January in the Eastern Cape (Buxton 1990) and spawning has been observed between November and February in the Goukamma area, Western Cape (Götz 2005).The age at 50% maturity is 2.5 years for females from the Eastern Cape (Buxton 1993) and 3.5 years for females from the Goukamma area in the Western Cape (Götz 2005). The length at 50% maturity occurs between 17.2 cm FL and 18.0 cm FL for females from the Eastern Cape and approximately 18.4 cm FL for females from the Western Cape (Götz 2005).
Generation length for C. laticeps is estimated to be eight years, using the following equation for a protogynous fish species: Generation length =SR* (Σxlxmx/Σlxmx)+(Σlxmx/Σlxmx)
|Generation Length (years):||8|
|Use and Trade:||Chrysoblephus laticeps is important to commercial and recreational ski-boat fisheries in the Eastern and Western Capes (Crawford and Crous 1982, Smale and Buxton 1985, Hecht and Tilney 1989). Recreational fishers usually have up to five crew members and operate from relatively small, outboard powered ski-boats while commercial fishers operate from both ski- and line-boats. Commercial line-boats are large harbour-based vessels capable of remaining at sea for more than a week (Buxton 1992). This species is also frequently speared by divers (Mann et al. 1997) and is occasionally taken by shore anglers fishing in deep water (Brouwer 1997, Götz et al. 2008b).|
Chrysoblephus laticeps is currently considered to be overexploited (Griffiths 2000) and although MPAs have provided protection for this species, some illegal fishing still occurs within them (Götz et al. 2008b). Chrysoblephus laticeps is vulnerable to overexploitation due to life history attributes including its sedentary and philopatric nature, slow growth, late maturation, longevity, and hermaphrotism (Buxton and Allen 1989, Buxton 1993, Kerwath et al. 2007a, 2007b). Sequential hermaphroditic species are subject to dramatic life history and demographic changes as a result of exploitation (Mariani et al. 2013). Chrysoblephus laticeps is able to maintain skewed sex ratios by shifting its size/age at sex-change in areas of low to moderate exploitation; however, this is likely to result in the decrease of overall individual size (Linde and Palmer 2008) which would prove detrimental to fisheries as a decrease in product value would result (Mariani et al. 2013). Areas of severe exploitation may not be able to maintain a balanced sex ratio which can result in gamete limitation, causing detrimental impacts to the reproductive output and genetic variation of this species (Chopelet et al. 2009, Mariani et al. 2013, Buxton 1987). Major threats to C. laticeps include localized overexploitation by recreational and commercial linefishers, particularly in areas in close proximity to major metropolitan areas (Griffiths 2000). A spawning biomass per recruit analysis of the male population of C. laticeps in the Goukamma MPA revealed the vulnerability of males to overexploitation, even at a reduced age-at-sex-change due to fishing, resulting in a high risk of recruitment failure for the population (Götz 2005). This species is susceptible to illegal-fishing within the boundaries of the no-take MPA which could severely compromise the function of the protected area (Götz et al. 2009).
The removal of large sparid fishes can change the community structure, and thus reduce both primary and secondary production in a temperate-reef ecosystem (Babcock et al. 1999) and can reduce the links of reef ecosystems with the pelagic food web. Virtually all South African warm-temperate, bottom-dwelling, subtidal linefish species have been overexploited, which can result in the loss of productivity, commensurate socio-economic loss and a high risk of commercial extinction, with harmful impacts to trophic flow and biodiversity being likely (Griffiths 2000). Chrysoblephus laticeps is an extremely resident species that relies on reef habitats of limited extent, which exacerbates its vulnerability.
The daily bag limit for the C. laticeps fishery is two fish, per person per day for recreational fishers and is unlimited for commercial fishers. The minimum size limit for C. laticeps is 30 cm TL, applying to all sectors of the fisheries. Daily bag limit and minimum landing size regulations may have limited effectiveness when fish are caught in deep water due to the effects of barotrauma (Kerwath et al. 2013b)
Chrysoblephus laticeps occurs in several no-take MPAs on the South African coast including Table Mountain (A. Bernard, South African Environmental Observation Network in prep.), De Hoop (Griffiths and Wilke 2002), Goukamma (Götz 2005; Götz et al. 2008b, 2013), Tsitsikamma (Buxton 1987, 1993, Götz et al. 2008b), Bird Island (Chalmers 2011), and Stilbaai MPAs (L. de Vos, UCT unpublished data). The abundance of C. laticeps females in the Goukamma MPA is projected to recover to 100% and male abundance to 80% of pre-exploitation values five years after exploitation has ceased (Kerwath et al. 2013a). The Goukamma MPA was established in order to protect to offshore reef habitat used by commercial important sparid species (WWF 2014). This MPA provides protection to a spawning population of C. laticeps with near pristine population parameters (Götz et al. 2009). It has been suggested that the seaward boundary of the Goukamma MPA be altered to coincide with a latitudinal line which may increase the function of the reserve as a harvest refuge for resident reef fishes such as roman, facilitate voluntary compliance and monitoring and prosecution of illegal fishing without a significant negative impact on the commercial linefishing fleet in the area (Götz et al. 2009).
Chrysoblephus laticeps has sustained fishing pressure better than many other South African endemic sparid fishes with relatively stable CPUEs (National Marine Linefish System unpublished data). This may be due to the small size at maturity (~18 cm FL) compared to the minimum legal size (27.2 cm FL) which allows individuals to reproduce at least once before they are introduced to the fishery (Götz and Kerwath 2011). Furthermore, because of its small home range (Kerwath et al. 2007a, 2007b), this species can be effectively protected within small to medium size MPAs (Götz et al. 2008a). It is suggested that if compliance issues are adequately addressed, current size and bag limits retained, and the expansion of the MPA network in South Africa is continued, the restoration of C. laticeps should prove successful (Götz and Kerwath 2011, Götz et al. 2013).
|Citation:||Mann, B.Q., Buxton, C.D. & Carpenter, K.E. 2014. Chrysoblephus laticeps. The IUCN Red List of Threatened Species 2014: e.T170170A1286872.Downloaded on 18 October 2017.|
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