|Scientific Name:||Kajikia albida|
|Species Authority:||(Poey, 1860)|
Tetrapturus albidus Poey, 1860
Tetrapturus lessonae Canestrini, 1861
|Taxonomic Notes:||This species was previously known as Tetrapturus albidus (Collette et al. 2006). There is a question as to whether this species is distinct from the Pacific Striped Marlin, Kajikia audax (Graves 1998, Collette et al. 2006, Hanner et al. 2011).|
|Red List Category & Criteria:||Vulnerable A2bd ver 3.1|
|Assessor/s:||Collette, B., Amorim, A.F., Bizsel, K., Boustany, A., Carpenter, K.E., de Oliveira Leite Jr., N., Die, D., Fox, W., Fredou, F.L., Graves, J., Viera Hazin, F.H., Hinton, M., Juan Jorda, M., Masuti, E., Minte Vera, C., Miyabe, N., Nelson, R., Oxenford, H., Restrepo, V., Schratwieser, J., Teixeira Lessa, R.P. & Pires Ferreira Travassos, P.E.|
|Reviewer/s:||Russell, B., Elfes, C. & Polidoro, B.|
There has been a continuous decline in the abundance of White Marlin since the beginning of exploitation of this species. Using a generation length of between 4.5 and 6.5 years, the estimated decline in overall stock abundance is 9–37% over a period of 13 and 20 years, respectively. The most recent stock assessment shows a slight stabilization or increase in abundance in recent years, however, more data are needed to confirm whether this is accurate. Considering that this species is well below the biomass at maximum sustainable yield (BMSY) and is not considered to be well managed, it is listed as Vulnerable under criterion A2.
|Range Description:||Found throughout warm waters of the Atlantic from 45°N to 45°S including the Gulf of Mexico, Caribbean Sea, and Mediterranean (Nóbrega et al. 2009). Records from the Mediterranean Sea and from Bretagne, France seem to be based on a few straying individuals.
Its distribution shows some seasonal variation, being most found in the highest latitudes only during warmer periods of the year (Ferreira and Hazin 2004). It is normally found in waters where the surface temperature is above 22°C, in waters over 300 m in depth and within a salinity range from 35–37% (Ferreira and Hazin 2004).
Previous reports have mentioned spawning of White Marlin off southeast Brazil in the same area where Blue Marlin spawn, but later in the year from April to June. Off southern Brazil (25–26ºS and 40–45ºW) White Marlin spawn from December to March. In the northwest Atlantic, White Marlin have been reported to spawn in the Gulf of Mexico in June. Recent reports confirm that White Marlin also spawns offshore and north of the Antilles (19–23ºN and 60–70ºW) between April and July.
Native:Algeria; Angola (Angola); Anguilla; Antigua and Barbuda; Argentina; Bahamas; Barbados; Belize; Benin; Bermuda; Brazil; Cameroon; Canada; Cape Verde; Cayman Islands; Colombia; Congo; Congo, The Democratic Republic of the; Costa Rica; Côte d'Ivoire; Cuba; Dominica; Dominican Republic; Equatorial Guinea; France; French Guiana; Gabon; Gambia; Ghana; Gibraltar; Greece; Grenada; Guadeloupe; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; Italy; Jamaica; Liberia; Libya; Malta; Mauritania; Mexico; Montserrat; Morocco; Namibia; Netherlands Antilles; Nicaragua; Nigeria; Panama; Portugal (Azores, Madeira); Puerto Rico; Saint Helena, Ascension and Tristan da Cunha; Saint Kitts and Nevis; Saint Lucia; Saint Vincent and the Grenadines; Sao Tomé and Principe; Senegal; Sierra Leone; South Africa; Spain (Canary Is.); Suriname; Togo; Trinidad and Tobago; Tunisia; Turkey; Turks and Caicos Islands; United States; Uruguay; Venezuela, Bolivarian Republic of; Virgin Islands, British; Western Sahara
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – northeast; Atlantic – northwest; Atlantic – southeast; Atlantic – southwest; Atlantic – western central; Mediterranean and Black Sea; Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
This species is occasionally caught in the Mediterranean Sea with no known population information. It is unclear whether there are two separate stocks or a single population in the Atlantic (Collette et al. 2006). The most recent ICCAT stock assessment considers a single stock in the Atlantic (ICCAT 2007).
Catch for the Atlantic: recorded since 1956 when total catch was minimal; peaked in 1965 at nearly 5,000 t, then oscillated between 1,000 and 1,500 t until 1993; increased to 1,900 t in 1994; declined below 1,000 t from 1995–2004 (ICCAT 2007). During the 2006 marlin assessment it was noted that catches of Blue Marlin and White Marlin continued to decline through 2004. The estimate for 2005 was 597 t. The recent biomass most likely remains well below BMSY estimated in the 2002 assessment. Over the period 2001–2004 combined longline indices and some individual fleet indices suggest that the decline has been at least partially reversed, but some other individual fleet indices suggest that abundance has continued to decline. Confirmation of these recent apparent changes in trend will require at least an additional four or five years of data, especially since the reliability of the recent information has diminished and may continue to do so.
It is important to note that the decrease in catches is associated with ICCAT regulations that were put in place in 2001 regarding the mandatory release of live white marlin taken by pelagic longlines. In addition in 2003, there was the imposition of catch limits to 33% of the 1996 or 1999 reported values. Countries are now reporting their landings, not their total catch.
The most recent stock assessment (ICCAT 2007) used a Bayesian Surplus Production model to estimate biomass from 1990 through 2006. The remaining data series (1956–1989) are based on biomass estimates from the previous stock assessment (ICCAT 2003). Population declines were examined using a generation length estimated between 4.5 and 6.5 years. Over a three generation length period of 13 years, the decline was 8.67% and over a three generation length period of 20 years, the decline was 36.74%. These declines were calculated using the biomass estimate of the first to the last year of the range examined. Population reduction for Atlantic White Marlin was therefore estimated to be between 9% and 37%.
In addition, there is still a high degree of uncertainty regarding biological parameters for this species. Landings of White Marlin may also be misidentified with Tetrapturus georgii. The proportion of T. georgii has increased dramatically in catches from 2–32 % in the past decade, which increases the uncertainty of the status of White Marlin (Beerkircher et al. 2009).
|Habitat and Ecology:||
This is a pelagic, oceanodromous species that usually occurs above the thermocline. Its distribution varies seasonally, reaching higher latitudes in both the north and south hemispheres only during the respective warm seasons. It is usually found in pelagic habitat in waters over 50 m depth with surface temperatures over 22°C and salinities of 35–37 ppt.
It migrates into subtropical waters to spawn, with peak spawning occurring in early summer. The spawning areas are found in deep and blue oceanic waters, generally at high temperatures ranging from 20–29°C except in the south Atlantic gyrals, and high surface salinities (over 35 ppt).
Lucena-Fredóu and Asano-Filho (2006) found individuals ranging from 153–290 cm (upper jaw fork length (FL) in the Brazilian northern coast. The 290 cm animal is the largest recorded to date, with a weight of 120 kg. Nóbrega et al. (2009) caught individuals from 105–207 cm of fork length (FL) on Brazilian northeast.
Longevity is estimated at 15 years (Ortiz et al. 2003). Hazin (et al. in prep) studying individuals from Brazilian northeast, found a size at first sexual maturity (at L50) of 138.5 cm of low jaw fork length (LJFL) for males and 145 cm for females, and a higher mean of gonad index in May and June for both genders. The age of maturity was estimated to be 2.5–4 years of age (Collette et al. 2011). There is no apparent sexual dimorphism but females attain larger sizes than males.
Given an observed longevity of 15 years and a length of maturity (L50) of approximately 145–160 cm, we infer an age of 50% maturity of 2.5–4 years (both sexes) and a generation length of 4.5–6.5 years (Collette et al. 2011).
White Marlin are known to frequently kill or stun their food by spearing it or hitting it with their bill (Nakamura 1985). Squids are an important part of their diet but they also feed on crustaceans and a wide variety of fishes such as dolphinfish, jacks, and flyingfishes (Nakamura 1985, Vaske et al. 2004).
The all-tackle game fish record is of a 82.5 kg fish caught off Vitoria, Brazil in 1979 (IGFA 2011).
This species is primarily taken by longline fisheries (including various EU longline fisheries), but also by purse seines (including EU purse seiners catching a few hundreds tonnes yearly), by some artisanal gears which are the only fisheries targeting marlins (Ghana, Cote d'Ivoire, including EU ones in the Antilles) and also by various sport fisheries located in both sides of the Atlantic.
Over 90% of the reported landings are attributed to bycatch in longline fisheries and there are also important directed recreational fisheries (Restrepo et al. 2003). Despite voluntary conservation measures, mandated minimum size limits, and wide acceptance of catch-and-release, white marlin are currently considered to be severely overfished (Restrepo et al. 2003, Jesien et al. 2006). The most recent assessment (ICCAT 2007) states that the biomass for 2000–2004 most likely remained well below the BMSY estimate in the 2002 assessment (ICCAT 2007). The observed distribution of several large pelagic predators, including the white marlin, has significantly contracted from the 1960s to 2000 (Worm and Tittensor 2011). A petition to declare white marlin an endangered species in the USA was not accepted (White Marlin Review Team 2002).
The increasing use of anchored fish aggregating devices (FADs) by various artisanal and sport fisheries is increasing the vulnerability of these stocks (STECF 2009).
This is a highly migratory species mentioned in the Annex I of the 1982 Convention on the Law of the Sea (FAO Fisheries Department 1994).
Size limitations, encouragement of catch-and-release sport fishing, and recommendations for using circle hooks instead of J-hooks are measures designed to increase survival in catch-and-release sport fishing (Pine et al. 2008, Serafy et al. 2009). In the US Atlantic, commercial harvest and import of either species of marlin is prohibited. The recreational fishery is limited to a total landing of 250 blue and white marlin combined per year. Bermuda and Bahamas similarly do not allow commercial harvest of these species. Mexico allows no commercial take within 50 miles off its coast. In the Brazilian Atlantic, there is a mandatory release of all live marlin caught and a prohibition of sale of any marlin landed. There are no conservation measures for this species in the Mediterranean Sea.
International Commission for the Conservation of Atlantic Tunas (ICCAT) recommendations [Rec. 00-13], [Rec. 01-10] and finally [Rec. 02-13] placed additional catch restrictions for blue marlin and white marlin. The latter established that “the annual amount of blue marlin that can be harvested by pelagic longline and purse seine vessels and retained for landing must be no more than 33% for White Marlin and 50% for Blue Marlin of the 1996 or 1999 landing levels, whichever is greater”. That recommendation established that, “All Blue Marlin and White Marlin brought to pelagic longline and purse seine vessels alive shall be released in a manner that maximizes their survival. The provision of this paragraph does not apply to marlins that are dead when brought along the side of the vessel and that are not sold or entered into commerce”. Catches of both species have declined since 1996–99, the period selected as the reference period by the recommendations. Since 2002, the year of implementation of the last of these two recommendations, the catch of white marlin has been at about the 33% value recommended by the Commission. This analysis represents only longline caught marlin even though the recommendations referred to the combined catch of pelagic longline and purse seine because the catch estimates of billfish by-catch from purse seine vessels are more uncertain than those from longline. In 2006, more countries started reporting data on live releases. Additionally, more information has come about, for some fleets, on the potential for using gear modifications to reduce the by-catch and increase the survival of marlins (STECF 2009).
The ICCAT-SCRS in 2006 requested the ICCAT, at a minimum, to continue the management measures already in place because marlins have not yet recovered. The Commission should take steps to assure that the reliability of the recent fishery information improves in order to provide a basis for verifying possible future rebuilding of the stocks. Improvements are needed in the monitoring of the fate and amount of dead and live releases, with verification from scientific observer programs; verification of current and historical landings from some artisanal and industrial fleets; and complete and updated relative abundance indices from CPUE data for the major fleets. Should the Commission wish to increase the likelihood of success of the current management measures of the marlin rebuilding plan, further reduction in mortality would be needed, for example by: implementing plans to improve compliance of current regulations; encouraging the use of alternative gear configurations, including certain types of circle hooks, hook/bait combinations etc., in fisheries where its use has been shown to be beneficial; broader application of time/area catch restrictions.
Given the recent importance of the catch from artisanal fisheries, and to increase the likelihood of recovery of marlin stocks, the Commission should consider regulations that control or reduce the fishing mortality generated by these fisheries. The Commission should encourage continued research on development of methods to incorporate this information into stock assessments in order to provide a basis for increasing the certainty with which management advice can be provided. STECF stresses the need for correct identification and reporting of billfish species in all EU fisheries.
|Citation:||Collette, B., Amorim, A.F., Bizsel, K., Boustany, A., Carpenter, K.E., de Oliveira Leite Jr., N., Die, D., Fox, W., Fredou, F.L., Graves, J., Viera Hazin, F.H., Hinton, M., Juan Jorda, M., Masuti, E., Minte Vera, C., Miyabe, N., Nelson, R., Oxenford, H., Restrepo, V., Schratwieser, J., Teixeira Lessa, R.P. & Pires Ferreira Travassos, P.E. 2011. Kajikia albida. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 December 2013.|
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