|Scientific Name:||Semicossyphus pulcher|
|Species Authority:||(Ayres, 1854)|
Labrus pulcher Ayres, 1854
Pimelometopon pulcher (Ayres, 1854)
|Red List Category & Criteria:||Vulnerable A2bd ver 3.1|
|Assessor(s):||Cornish, A. & Dormeier, M. (Grouper & Wrasse Specialist Group)|
|Reviewer(s):||Sadovy, Y. & Ng Wai Chuen (Grouper & Wrasse Red List Authority)|
Recent (last decade) increases in the level of exploitation, especially for the lucrative live fish trade, the catch of juveniles or small females, the life-history of the animal (i.e., large, long-lived, relatively slow to reach sexual maturation and sex-changing), and a limited geographic range are all factors that indicate that this species should be carefully monitored in the near future. This species was intensively fished in the past (at levels nearly as high as those in the late 1990s) in the 1920s but interest waned after a decade or so, which may have allowed stocks time to recover. Fishing pressure increased in the last decade.
Mainly juveniles are included in important commercial trap fishery, with juveniles and smaller adults dominating the hook and line and recreational fishery. Male numbers seem typically low which could result in sperm limitation for the species, with further male reduction, resulting in reduced reproductive output: males are readily targeted in the recreational spear fishery.
Commercial and recreational fishing pressure has increased (there is also an artisanal sector) and catches have declined over the last decade. Given the growing popularity of the live fish trade and its appeal for high retail prices, pressure may well grow in this commercial sector in particular, especially if prices increase as the species becomes less readily available.
Although variability in catches could be due to natural recruitment variation and also to changes in fishing effort; indications are that effort is likely to be increasing for commercial use and data from logbooks suggest that Catch Per Unit Effort (CPUE) has declined approximately 3-fold since the 1980s (Fig. 4.4.d in Alonzo et al. 2004). Recent declines in landings could be, at least in part, the consequence of management introduced in 2002. The effect of environmental conditions on recruitment is not known.
The natural history of this species, including its limited geographic range along inshore habitat, the likely increasing interest in the fishery and the currently unsustainable fishing levels (according to the models of Alonzo et al. 2004), together with the difficulties in enforcing existing regulations strongly suggest that this species will continue to decline if stronger protective action is not put into place.
In terms of the IUCN Red List Criteria, the extent of occurrence and area of occupancy are small enough to qualify this species as Endangered except that additional conditions related to these areas being in decline, population being severely fragmented or suffering extreme fluctuations are not met. However, the population has declined, judging primarily by a three-fold decline in CPUE. This could qualify S. pulcher as Endangered under reductions in population size >50% over the last three generations where the reduction and its causes have not ceased, and based on an index appropriate to the taxon (EN A2b). However, as such a large decline is not supported by landings data, and as increasingly stringent management has been enacted since 1999, S. pulcher is listed for now as Vulnerable based on a lesser reduction in population size of >30% (VU A2bd).
|Range Description:||Occurs in the eastern Pacific. Ranges from Point Conception in California, to Guadalupe Island (off northern central Baja California) and the Gulf of California, Mexico. However, the species is rare south of Punta Abreojos, apart from a small population at Isla Santa Margarita, near Bahia Magdalena (Cowen 1985). Water current anomalies may occasionally result in larvae of this species recruiting to reefs as far north as Monterey Bay (Cowen 1985).
Sheephead are found from Monterey Bay to the Gulf of California (Alonzo et al. 2004) but are uncommon north of Point Conception and are much less common in the Gulf of California than along the Pacific Coast (Miller and Lea 1972). In the Channel Islands, densities of 1,475–1,525 individuals of all sizes per hectare have been observed (Davis and Anderson 1989) while another survey, which covered much of the geographic range of the species (Point Conception to Isla Santa Margarita) (Cowen 1985) reported density range between 16–290 adult fish per hectare.
Extent of Occurrence and Area of Occupancy Notes:
Although this species is found from Point Conception (north of Santa Barbara) to Baja California and the Gulf of California, it is rare from Punta Abreojos south with the exception of Isla Santa Margarita (Cowen 1985). Suitable rocky reef area is assumed to extend 1 km offshore from land. The extent of occurrence is assumed to be the rocky reef area from Point Conception to Mazatlan at the mouth of the Gulf of California, and was calculated as 4,770–5,800 km² (5,300 +/- 10% to allow for inaccuracies in the calculations).
The area of occupancy is assumed to be the rocky reef area from Point Conception to Punta Abreojos (including Isla Santa Margarita) and was calculated as 1,692–2,070 km² (1,880 km² +/- 10% to allow for inaccuracies in the calculations).
Decline in extent of occurrence or area of occupancy has not been reported for the species. The California Sheephead inhabits rocky reefs, which are assumed not to fluctuate in size or quality, or be in decline. There is also no evidence of any habitat bottlenecks that could increase the vulnerability of this species although there is a suggestion that kelp beds could be important to part of their life history (Stephens 1992).
Native:Mexico (Baja California, Baja California Sur, Guadalupe I.); United States (California)
|FAO Marine Fishing Areas:|
Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The recreational catch for 1999 was estimated at 77,226 fish with an estimated mean weight of 2.36 pounds (personal communication from the database of the National Marine Fisheries Service, Fisheries Statistics and Economics Division, Silver Spring, MD, 2001). If it is assumed that the average weight of commercially caught fish is the same, then 54,190 (129/767 pounds / 2.36) fish were caught in 1999 giving a total of 132,136 fish caught in commercial and recreational fisheries in 1999. Since 1999 both commercial and recreational catches have fluctuated although by 2003 the combined (total) catch had declined by 20%.
The maximum number of fishes in the population was calculated by the highest density of this species recorded for a site by underwater visual census (from Cowen 1985), multiplied by the area of occupancy. This seems reasonable as (1) densities were observed in the early 1980s prior to the recent increase in exploitation and (2) California Sheephead are reportedly rare outside the area of occupancy (see Extent of Occurrence and Area of Occupancy Notes above).
The highest density recorded was 8.5 mature individuals (calculated from Table 2 in Cowen 1990) per 250 sq. m. The upper estimate for the area of occupancy is 2,070 sq.km. This gives an upper population size of 70,380,000.
Landings data from Mexico appear to have become severely reduced between 1950 and 1976 – no further data are available. No CPUE data are available so it is not known whether effort changed over this time period.
The commercial fishery for California Sheephead has shown distinct phases in fishing effort and only really became a significantly commercially targeted species in the 1980s/90s (Stephens 1992, Alonzo et al. 2004) as follows:
1960s: 2,150 - 12,708 kgs per year
1970s: 1,393 - 5,055 kgs per year
1980s: 4,130 - 110,547 kgs per year
1990s: 56,031 - 166,217 kgs per year
2000: 78,680 kgs per year
2001: 68,130 kgs per year
2002: 54,710 kgs per year
2003: 48,000 kgs per year
Sources: Leet et al. 1992; personal communication from the National Marine Fisheries Service, Fisheries Statistics and Economics Division, Silver Spring, MD, 2001; and Alonzo et al. 2004.
Recreational landings data, which can equal or exceed commercial landings (Stephens 1992), are only available in numbers of fish as follows:
Mean numbers of fish caught per year in recent decades were
1960s: 11,541 - 52,967 fish per year
1970s: 28,512 - 46,234
1980s: 21,072 - 68,972
1990s: 18,363 - 43,150
Below, recreational landings from Alonzo et al. 2004
1960s: 22,500 – 89,490 kgs per year
1970s: 49,940 – 78,600 kgs per year
1980s: 64,640 – 223,300 kgs per year
1990s: 45,500 – 121,120 kgs per year
2000: 100,090 kgs per year
2001: 58,850 kgs per year
2002: 60,260 kgs per year
2003: 68,510 kgs per year
Note that the above are landings data – there are no indications of fishing effort.
Although variability in catches could be due to natural recruitment variation and also to changes in fishing effort; indications are that effort is likely to be increasing for commercial use and data from logbooks suggest that CPUE has declined approximately 3-fold since the 1980s (Figure 4.4.d in Alonzo et al. 2004). Exploitation rate is estimated to have increased in recent history regardless of the estimate of natural mortality used (Alonzo et al. 2004).
Given that there is a fishery catching approximately 100,000 individuals of a large reef fish species that occupies a small geographic range, it seems very unlikely that the Sheephead population is expanding. At one extreme then, the population is assumed not to have changed in size (0% reduction). At the other extreme, it seems unlikely the population could have declined more than 50% overall without a marked decrease in landings in the US, something which is not apparent. The value of 50% is intuitive and is intended as an outside estimate.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Inhabits rocky reefs, especially where there are kelp beds. It occurs from 0–55 m depth (Eschmeyer et al. 1983) although around Cabo San Lucas (southern tip of Baja California) it occurs only in deeper water, 60–100 m (Cowen 1985). The fish tend to stay in the same reef and do not move around a lot, as shown by tag-recapture research (DeMartini et al. 1994). |
Maximum age is at least 50 years (Fitch and Lavenberg 1971); such old individuals are likely to be very rare, however. The oldest fish of 276 collected from 4 unexploited populations throughout the range of the California sheephead was 21 years (Cowen 1990). Furthermore, the oldest individual of 470 fish taken off California and Mexico in the early 1970s was 20 years (Warner 1975).
Growth parameters vary among populations and studies (Alonzo et al. 2004). The value of k ranged from 0.007 to 0.068, while estimated Lsub>inf ranged from 45.46 to 464.16 (cm fork length). The k = 0.068 and Linf = 83.86 cm (maximum length) were the best fit to the observed size and age data (Alonzo et al. 2004).
The age of sexual maturity and age of sex changeover (from female to male) shows great variation depending on location (Cowen 1990). For instance, at Santa Nicholas Island off California, the species becomes sexually mature (as females) at 5–6 years. Males did not predominate until ages 13–14. At the offshore Guadalupe Island, sexual maturity took place at 3–4 years with sexual transformation to males taking place at 5–6 years. Other locations in Mexico to the south of Guadalupe Island have populations that show ages of sexual maturity and changeover intermediate to the 2 aforementioned islands (Cowen 1990). Size of first sexual maturation varied from 12–18 cm SL in females and 18–28 cm SL in males, depending on location (Cowen 1990).
Size of 50% sexual maturation is approximately 20–30 cm, and sex change occurs roughly between 25 and 35 cm (Warner 1975, Cowen 1990).
In the area of Catalina Island, California, the Sheephead wrasse spawns from August to October, while sex change occurs during the winter months (Warner 1975, Cowen 1990). Individuals may spawn more than once a season. It has been estimated that females spawn approximately 86 times per year (about once every 1.3 days), batch fecundity of females is 5,755 eggs per spawning event, and there is no significant relationship between the number of eggs released per kilogram of body weight and total female body weight (average 15,000 eggs per kg) (DeMartini et al. 1994).
Generation time was calculated from samples of 4 relatively unexploited populations taken throughout the main area of distribution off California and Baja California (Cowen 1985). This species is protogynous, changing sex from female to male. Observed adult sex ratios in California Sheephead vary from 3:1 mature females to males to 0.8:1 (Cowen 1990). In unexploited populations, it seems likely that the females are limiting, although in exploited populations where males (as the larger animals) are targeted, males may ultimately become the limiting sex. The generation time for each location was calculated using the length frequency data for the females of the 4 populations (Figure 4 in Cowen 1990) and converting this to age frequency using the length-age relationship data (Figure 2 in Cowen 1990). Generation time, as the mean age of mature females varied from 4.1 to 8.5 years across the 4 populations, these are therefore set as the plausible limits of generation time. The mean of the 4 generation times calculated, 6.8, is assumed to be representative of the entire population and was, therefore, used as the point estimate.
The species is a generalist carnivore (Cowen 1983), feeding on mussels and red sea-urchins and may play an important role in regulating prey density (see citations in Alonzo et al. 2004).
Natural mortality is likely to be in the order of M=0.2 (Alonzo et al. 2004).
How effectively protected is this species in designated marine reserves since MPAs are probably an important management measure for this species?
It would be very useful to have recent fisheries independent data on California Sheephead stocks. At present, landings would have to decrease over a number of years with a constant or increasing fishing effort in order to recognise falling stocks. The obvious way to achieve fisheries independent data and quickly assess the state of fish stocks would be to repeat the underwater visual census work of Cowen (1985, 1990) and compare the data with his pre-intensive exploitation figures. In the meantime, changes in CPUE are likely to offer the best indications of changes in abundance.
There seems to have been little work on the ecology of this species. It would be important to know if populations of Sheephead were affected by changes in environment, or habitat, such as changes in the extent and quality of kelp beds.
Data from Mexico on landings and CPUE from 1976 onwards are needed.
The fishery for this species, which began in at least the late 1800s (for salted fish), peaked in 1928 with landings of 370,000 pounds. This may have been as the species was easily available close to port, and the species has maintained a presence in the California nearshore fishery (Alonzo et al. 2004). From the 1940s to 1980s there was little interest in the Sheephead and catches were usually under 10,000 pounds. Fish are taken by trap, set net, speargun and hook and line (Alonzo et al. 2004).
The fishery greatly increased from the late 1980s to the present. At least some of the new demand is for small and live fish, usually pre-reproductive females kept live in tanks in Asian seafood restaurants, prior to being eaten (Stephens 1992). While the Sheephead population was considered stable up until the early 1990s, the targetting of these juvenile animals gives some cause for concern (Stephens 1992) as some fish, mostly females, are being taken before they have had a chance to reproduce. Such fish will be up to 12–18 cm SL, depending on where they were caught (see size of sexual maturity in Cowen 1990), and are desired as they are small enough for the restaurant tanks. The live fish fishery resulted in considerably increased landing, reaching a peak of 166,364 kgs in 1997. During this time period, the prices (adjusted for the effects of inflation) increased from 0.10US$/lb in the 1940s to over $9.00/lb in the 1990s for live fish (Stephens 2001).
Recreational fish landings were higher than commercial landings in the 1980s and in 2002, the Sheephead was 13th in the recreational fishery in southern California. Large and old individuals are vulnerable to depletion by spearing since they are readily speared (CDFG 2003).
As an example of growth of the high value live fish (trap and hook and line) fishery for this species, between 1989 and 1992, increased from 2–27 boats landing over 23,636 kgs of live fish (Palmer-Zwahlen et al. 1993 cited in Alonzo et al. 2004). The Sheephead accounted for more than 88% of live fish landing in the developing live-fish fishery.
Recruitment in southern regions of the California Sheephead geographic range appears to be primarily from northern regions as this is the primary direction of current flow (Cowen 1985). If fishing were to reduce the numbers of breeding adults in the north (i.e., the US), this could result in decreased recruitment, and therefore numbers of mature adults, in the south (i.e., Mexico).
Of the 19 nearshore species managed under the Nearshore Fishery Management Plan (NFMP), 16 (13 species of nearshore rockfish, California Scorpionfish, Cabezon, and Kelp Greenling) are designated as groundfish and fall under the management authority by the Pacific Fishery Management Council (PFMC). California Sheephead, Monkeyface Prickleback, and Rock Greenling do not have ‘groundfish’ designation, and thus are not managed by the PFMC (Alonzo et al. 2004). This lack of PFMC management led to State of California regulations for California Sheephead and few other species (CDFG 2002). Regulations for California Sheephead tend to fall under the general nearshore fishery regulations. The commercial fishery for both trap and hook and line gear is a restricted access fishery. Permits for the live-fish trap fishery began in 1996 in southern California and a statewide Nearshore Fishery Permit began in 1999. These permits are limited to individuals who have participated in the fishery the previous year as well as meeting historical catch criteria.
The Sheephead trap and hook and line fisheries reached optimal yield (OY) levels and closed early for all years beginning in 2001. According to the NFMP, "Optimum Yield" (OY) is defined in FGC section 97 (see Alonzo et al. 2004. p. 3) as the amount of fish taken in a fishery that does all of the following: (a) provides the greatest overall benefit to the people of California, particularly with respect to food production and recreational opportunities, and takes into account the protection of marine ecosystems, and (b) is the MSY of the fishery, reduced by relevant economic, social, or ecological factors, and (c) in the case of an overfished fishery, provides for rebuilding to a level consistent with producing MSY in the fishery (CDFG 2002). The 2002 OY was set to half that of total recent catches, and allocated almost 22,727 kgs more to the recreational fishery than the commercial fishery (Alonzo et al. 2004).
Size restrictions on Sheephead were fairly minimal before 1999 for both the recreational and commercial fisheries. In 1999, CDFG set the minimum catch size for the commercial fishery to 12 inches (total length) and followed with the same size limit for the recreational fishery in 2001. To further decrease commercial harvest, the minimum commercial harvest size was increased to 13 inches in 2001. Also in 2001, the 10 fish recreational bag limit was reduced to five (CDFG 2002).
In 2002, the Sheephead fishery was aligned with the nearshore rockfish fishery for both the commercial and recreational fisheries (CDFG 2002). Sheephead are not to be taken commercially north of Point Conception, Santa Barbara County during March and April, and south of Point Conception during January and February. This essentially represents a seasonal closure because the bulk of landings occur south of Point Conception (CDFG 2002). Other season and area closures affecting the Sheephead fishery result from management of the nearshore fishery. In 2001, taking Sheephead deeper than 20 fathoms in a Cowcod Conservation Area was banned.
|Citation:||Cornish, A. & Dormeier, M. (Grouper & Wrasse Specialist Group). 2006. Semicossyphus pulcher. The IUCN Red List of Threatened Species 2006: e.T61340A12464899.Downloaded on 05 December 2016.|
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