The blackfin tuna (''Thunnus atlanticus'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max len ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Scombridae The mackerel, tuna, and bonito family, Scombridae, includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies. All species are in the subfamily Scombrinae, except the butterf ...

. It is occasionally referred to as the bermuda tuna, blackfinned albacore, or deep bodied tunny. They are the smallest

species in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

Thunnus ''Thunnus'' is a genus of ocean-dwelling, ray-finned bony fish from the mackerel family, Scombridae. More specifically, ''Thunnus'' is one of five genera which make up the tribe Thunnini – a tribe that is collectively known as the tunas. ...

'', generally growing to a maximum of in length and weighing 21 kg (46 lb). Blackfin tuna are considered tropical, warm water fish. They have a relatively small distribution throughout the Eastern Coast of North and South America. They are located from Massachusetts to Rio de Janeiro in Brazil, and also inhabit the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

and the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

. The blackfin tuna has less commercial value than its close relatives like the yellowfin, bluefin, and skipjack tuna, but is still a major sport fish in Florida and regions of the Caribbean like

Cuba Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...

and the

Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the ar ...

. However, the taste and quality of blackfin tuna is comparable to that of its popular relatives, and can be prepared in the same ways. It is also sushi grade. Methods of capture include trolling, drift fishing, and sport fishing with a pole and live bait or lures like ballyhoo, mullet, small fishes or strip baits, feathers, jigs, or plugs. As of 2010, blackfin tuna were deemed “least concern” by the IUCN.

Description

Blackfin tuna are the smallest species of tuna. The All-Tackle world record blackfin tuna was caught off the coast of Florida and weighed 20.6 kg (45 lbs 8 ounces). Their oval shaped bodies have a dark blue to black colored back. The sides and belly of the fish are silver, which gives them an iridescent appearance in the water, with a lateral yellow stripe. They have durable, compact scales with an oblique mouth. Blackfin tuna have small dorsal

finlet Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as s ...

s with a brownish coloration and white edges, a distinguishing characteristic from the yellow

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

s seen in other types of tuna. These dorsal finlets draw a line between the two large dorsal fins and the tail. Blackfin tuna can also be distinguished from other types of tuna based on their number of gill rakers. Most species of tuna have a minimum of 30 gill rakers, while blackfin tuna only have 20-23, the fewest of all species. Additionally, blackfin tuna have a smooth

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

surface on their liver found in the chest cavity, while other species have striations on their ventral surface.

Biology/Ecology

Blackfin tuna hunt both

epipelagic The photic zone, euphotic zone, epipelagic zone, or sunlight zone is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological proc ...

(surface) and

mesopelagic The mesopelagic zone (Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins at ...

(deeper water) fish and squid. They also eat

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s such as shrimp, crabs, amphipods,

stomatopod Mantis shrimp, or stomatopods, are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 340 million years ago. Mantis shrimp typically grow to around in length ...

s, and the larvae of

decapods The Decapoda or decapods (literally "ten-footed") are an order (biology), order of crustaceans within the class Malacostraca, including many familiar groups, such as crabs, lobsters, crayfish, Caridea, shrimp and Dendrobranchiata, prawns. Most ...

. They consume smaller prey by filtering the water and chase to catch larger prey. This species is host to 9 known

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

including Digenea,

Monogenea Monogeneans are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they have both male and female repro ...

cestoda Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of ...

nematoda The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...

copepods, and

cookiecutter shark The cookiecutter shark (''Isistius brasiliensis''), also called the cigar shark, is a species of small squaliform shark in the family Dalatiidae. This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been rec ...

. The remaining parasites are parasitic copepods like caligus

coryphaena ''Coryphaena'' is a genus of marine ray-finned fishes known as the dolphinfishes, and is currently the only known genus in the family Coryphaenidae. The generic name is from Greek κορυφή (''koryphē'', "crown, top") and -αινα (-''aina' ...

, C. productus, Euryphorus brachpterus, and pseudocycnus.

Life History

They are a short-lived, fast-growing species; a 5-year-old fish would be considered old. They reach

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definit ...

at the age of 2 years when they weigh roughly 4-6 lbs. Juvenile stages of all Tuna species are very similar due to close life histories, although the species have significant differences as adults.

Spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

typically occurs off the coast of Florida in the months between April and November. In the Gulf of Mexico and near northern Brazil spawning occurs from June to September. In fact, the Gulf of Mexico is thought to be one of the most ideal spawning sites for blackfin tuna. The physiochemical make-up of the Gulf of Mexico makes it an indispensable nursery habitat. One factor potentially influencing the favorable conditions of the Gulf of Mexico is the nutrient outflow from the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it fl ...

; this outflow feeds the high metabolism of larval blackfin tuna. Blackfin tuna are a warmer-water fish, preferring water temperatures over 20 °C (68 °F). The females release eggs into the water column to be fertilized by sperm. Fertilization of their eggs produces

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

larvae which can be found on the surface of the water all the way to depths of 164 feet. Blackfin tuna are preyed on by other, larger fish species such as

mahi-mahi The mahi-mahi () or common dolphinfish (''Coryphaena hippurus'') is a surface-dwelling ray-finned fish found in off-shore temperate, tropical, and subtropical waters worldwide. Also widely called dorado (not to be confused with ''Salminus brasi ...

(Coryphaena hippurus),

blue marlin ''Makaira'' (Latin via Greek: ''μαχαίρα'' "sword") is a genus of marlin in the family Istiophoridae. It includes the Atlantic blue, and Indo-Pacific blue marlins. In the past, the black marlin was also included in this genus, but today ...

(Makaira nigricans), and skipjack tuna (Katsuwonus pelamis). Various species of sea birds prey on blackfin tuna throughout their life cycle, and cannibalism has occurred as well.

Sustainable consumption

In 2010, Greenpeace International did not add the blackfin tuna, unlike other tuna species, to its seafood red list. Greenpeace International Seafood Red list

References

External links

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FishBase info for black tunaEncyclopedia of Life Info for Thunnus atlanticus
{{Taxonbar, from=Q784412 blackfin tuna Sport fish Fish of the Western Atlantic Fish of the Eastern United States Fish of the Caribbean Fish of the Dominican Republic Fish of Brazil blackfin tuna Taxa named by René Lesson