|Scientific Name:||Carcharhinus acronotus|
|Species Authority:||(Poey, 1860)|
Squalus acronotus Poey, 1860
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||Morgan, M., Carlson, J., Kyne, P.M. & Lessa, R.|
|Reviewer/s:||Stevens, J.D., Pollard, D., Dudley, S. & Valenti, S.V. (Shark Red List Authority)|
Blacknose Shark (Carcharhinus acronotus) is an abundant inshore and shelf whaler shark with a wide distribution in the western Atlantic from the southern USA, through the Gulf of Mexico and the Caribbean to southern Brazil. This tropical and warm-temperate shark is found at depths of 18?64 m and is fished in large numbers in parts of its range. It is caught in both the large and small coastal directed shark fisheries along the US Atlantic coast and is probably a target and bycatch in coastal fisheries throughout the rest of its range. It suffers considerable mortality as bycatch in US shrimp trawl fisheries causing the stock to be currently overfished. Shrimp trawl fisheries are intense in inshore waters throughout the Gulf of Mexico and on the Caribbean coast of South America. No information is available on catches or population trends for Blacknose Shark in this area, but it is possible that it is also declining there. However, analyses of data from northern and northeastern Brazil indicate that there is no evidence of population decline there, and large, mature adults are still present in catches. While the US population has declined, most of the decline has occurred since 2000 (less than one generation) and management actions will be required to rebuild the stock. This species is assessed as Near Threatened globally, reflecting continuing declines observed in the US Atlantic and apparently stable populations off northern Brazil. No species-specific data or information is currently available from the Caribbean Sea, and assessment of catches and population trends in this area is a priority. With further information from this region, the species may qualify for a threatened category (VU A2bd+A4bd). Population trends should continue to be monitored and efforts should be made to collect data throughout the rest of the species? South American range.
|Range Description:||Western Central and Southwest Atlantic: The Blacknose Shark ranges from North Carolina to southern Brazil, including the Gulf of Mexico. Recorded from North Carolina to Florida, USA, Bahamas, Gulf of Mexico, Virgin Islands, Puerto Rico, Antilles, Guyana, Venezuela, southern Brazil (Compagno in prep, Compagno et al. 2005).|
Native:Anguilla; Bahamas; Barbados; Brazil; Dominica; Grenada; Guadeloupe; Guyana; Martinique; Mexico (Campeche, Quintana Roo, Tabasco, Tamaulipas, Veracruz, Yucatán); Puerto Rico (Puerto Rico (main island)); Saint Kitts and Nevis; Saint Lucia; Saint Pierre and Miquelon; Saint Vincent and the Grenadines; Trinidad and Tobago; United States (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Texas); Venezuela (Venezuelan Antilles); Virgin Islands, British; Virgin Islands, U.S.
|FAO Marine Fishing Areas:||
Atlantic – southwest; Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
Common in coastal waters of the western north Atlantic Ocean from U.S. North Carolina to Florida, and throughout the Caribbean Sea, and the Gulf of Mexico. Recent stock assessment indicates the population in 2006 is 25% of virgin levels in the 1950s (Siegfried and Brooks 2007). Projections with zero fishing mortality indicates the stock rebuilds by 2019.
Preliminary analyses of data on Blacknose Shark from northern to northeastern Brazil (Recife and Maranhão State) show no indication of population decline and large, mature adults are still present in catches (R. Lessa pers. obs. 2007). This is the most abundant coastal elasmobranch on the Pernambuco coast (R. Lessa pers. obs. 2007). The R.V. Dr. Fridtjof Nansen conducted a survey of the northeast South American shelf in 1988 (the most recent known to date) (Chan A Shing 1999). This survey reported that Blacknose Shark was one of the most dominant species in the catch (with Caribbean Sharpnose Shark (Rhizoprionodon porosus) and Bonnethead Shark (Sphyrna tiburo)) (Chan A Shing 1999). Chan A Shing reports that Blacknose Shark is a common species in landings in Guyana and Trinidad and Tobago, but no information is currently available to identify temporal trends.
|Habitat and Ecology:||
A common coastal tropical and warm-temperate shark of the continental and insular shelves, mainly over sandy, shell and coral bottom, depths of 18?64 m (Compagno et al. 2005).
The species may possibly reach 200 cm total length (TL) (Compagno et al. 2005). Depending on the area, size at maturity is between 84.8 and 100.5cm Fork Length (FL) for females and 84.8?91.8 cm (FL) for males (Clark and von Schmidt 1965, Dodrill 1977, Schwartz 1984, Driggers et al. 2004, Sulikowski et al. 2007, Carlson et al. in press), In US South Atlantic waters males are reported to reach maturity at 4.3 years and females at 4.5 years of age (Driggers et al. 2004). Whereas in the Gulf of Mexico, males reportedly mature at 5.4 years and females at 6.6 years of age (Carlson et al. 2007). Longevity is estimated as 19 years in US South Atlantic waters and 16.5 years in the Gulf of Mexico, for females (Driggers et al. 2004, Carlson et al. 1999, Sulikowski et al. 2007). Generation period is estimated at eight years (Siegfreid and Brooks 2007) Reproduction is viviparous with a yolk-sac placenta. The species has a biennial reproductive cycle in US South Atlantic waters, but an annual cycle is reported in the Gulf of Mexico and off northern Brazil (Driggers et al. 2004, Sulikowski et al. 2007, Hazin et al. 2002). Females give birth to 1?5 pups after a gestation period of 9?11 months (Driggers et al. 2004, Carlson et al. 1999, Sulikowski et al. 2007). Size at birth is 31?35 cm FL (Driggers et al. 2004).
The species is apparently fished in large numbers in parts of its range (Compagno et al. 2005), and its inshore occurrence places it within the range of coastal fisheries throughout its distribution (Hazin et al. 2002). They constitute a substantial portion of the catch in coastal fisheries throughout their range and are often targeted due to their economic value (Driggers et al. 2004).
In USA waters, this species is caught in coastal gillnets along the eastern coast of the U.S. (Carlson and Bethea 2007, and reference therein), and the directed bottom longline fishery that operates from New Jersey to Louisiana (Hale and Carlson 2007, and reference therein). The major threat to this species is large removals as shrimp bycatch during juvenile life history stages (Siegfried and Brooks 2007).
This species is captured in coastal fisheries off Brazil, where inshore fishing pressure is often relatively intense. Although declines have been documented in other inshore Carcharhinid sharks off Brazil (e.g., Daggernose Shark (Isogomphodon oxyrhynchus)), this species is wider-ranging, distributed all along the Brazilian coast. CPUE data from northern and northeastern Brazil show no decline and large, mature adults are still present in catches (R. Lessa pers. obs. 2007).
Trawl fisheries for shrimp operate throughout the Gulf of Mexico (mainly in inshore waters) and take a substantial bycatch of elasmobranchs (Shepherd and Myers 2005).
No data are available to determine the impact of fisheries on this species throughout the rest of its range off South America. However, shrimp trawl fisheries are intense in many areas and efforts should be made to collect data on the catches of this species where no data are currently available. Trawl fisheries began off northeastern Venezuela in the late 1960s (Mendoza and Marcano 1994). Demersal trawl effort has increased in both effort and efficiency; 150 vessels were permitted to operate out of the port by the Ministry for Fisheries and Agriculture (DGSPAMAC) in 1990, each with 250?650 horse power (hp), giving a total nominal horse power of 37,500?97,500 hp (Mendoza and Marcano 1994). By 2003 the commercial trawl fleet had increased to about 400 shrimp trawlers operating on the continental shelf (Mendoza et al. 2003). In addition, an artisanal fleet of 20,000 small vessels and about 1,000 medium and long-range vessels exists (Mendoza et al. 2003). The medium and long range fleet targets medium pelagics using pelagic longline and snappers and groupers (Lutjanus purpureus and Epinephelus species) using hand line and demersal longline (Mendoza et al. 2003). Overall temporal trends in total reported catches for Venezuela showed a steep increase in landings through the 1980s and 1990s; from about 150,000 t/year to more than 350,000 t/year (Mendoza et al. 2003). Bycatch taken by shrimp trawlers off Venezuela was estimated at 96,000 tonnes annually and bycatch/shrimp ratios are typically between five and 15:1 in the region (Charlier 2000). Charlier (2000) indicates that, although only a small part of this catch is utilized, several species have apparently disappeared from the bycatch.
In US waters this species is managed in the small coastal shark complex under the National Marine Fisheries Service: Federal Fisheries Management Plan for Atlantic Tuna, Swordfish and Sharks. There are no specific measures in place elsewhere throughout its range.
It is recommended that population trends continue to be monitored.
|Citation:||Morgan, M., Carlson, J., Kyne, P.M. & Lessa, R. 2009. Carcharhinus acronotus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 23 May 2013.|
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