| Dogtooth tuna | |
|---|---|
 | |
| Gymnosarda unicolor from French Polynesia | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Scombriformes |
| Family: | Scombridae |
| Genus: | Gymnosarda Gill, 1862 |
| Species: | G. unicolor |
| Binomial name | |
| Gymnosarda unicolor (Rüppell, 1836) | |
| Synonyms [1] [2] | |
List
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The dogtooth tuna (Gymnosarda unicolor), also known as white tuna, is a species of pelagic marine fish which belongs to the family Scombridae.
The dogtooth tuna can reach a length of 190 to 248 centimetres (75 to 98 in) in males [3] [4] and a weight of 130 kilograms (287 lb). [5] The average length commonly observed is around 40 to 120 centimetres (16 to 47 in). They have 12 to 14 dorsal soft rays and 12 to 13 anal soft rays. The lateral line undulates strongly. [3] These large tunas have a streamlined shape and a distinctive body coloration: brilliant blue green on the back, silvery on the side, and whitish on the belly, with two white tips on the two back fins close to the caudal peduncle. They always swim with open jaws. The upper jaw of the large mouth reaches the eye. [3]
The dogtooth tuna is widespread throughout the tropical waters of the Indo-Pacific area from the eastern coast of Africa, Red Sea included, to French Polynesia and oceanic islands of the Pacific Ocean (Hawaii excluded), north to Japan, south to Australia. [1] [6]
These offshore fishes can be found mainly in reef environments [3] [5] with smaller fish being more commonly found near shallow reef areas and larger ones haunting deep reef drop off areas, seamounts and steep underwater walls. Usually they are solitary or occur in small schools, [3] to a depth of 10 to 300 metres (33 to 984 ft). [1]
The dogtooth tuna is one of the apex non-pelagic predators in its environment, sharing that position with giant trevally, Napoleon wrasse, and large groupers, as well as large sharks such as reef, bull and tiger sharks.
These aggressive opportunistic predators feed on small schooling fishes and squids, [3] and are capable of taking a wide variety of prey items. In most areas, the mainstay of its diet probably consists of pelagic schooling fish found near reef habitat (mainly, Caesio , Cirrhilabrus , Pterocaesio , carangids such as rainbow runners and Decapterus , mackerel scad, and scombrids). [3]
Preliminary estimates of longevity indicate a maximum observed age of at least 20 years. [7]
These fishes are usually marketed canned and frozen. Adults may be ciguatoxic. [3] The dogtooth tuna is appreciated in most of its range as a fine food fish and also as a game fish sought by both rod and reel anglers and spearfishermen. Dogtooth tuna used to be mostly taken as an incidental catch by anglers trolling for other gamefish - with natural baits for black marlin, for instance, or with lures for wahoo and Spanish (narrowbarred) mackerel. In the last 10 to 15 years[ when? ] there has been more dedicated effort directed at this species because of its rarity and sporting qualities. Dogtooth tuna are now a highly coveted prize by many European and Asian sports anglers. Large specimens are seldom found where there is significant fishing pressure and can be one of the most difficult gamefish to capture.
Their habit of making high-speed downward runs when hooked, even on heavy tackle, often sees the line being cut as it contacts deep bottom structure. Sharks frequently mutilate both hooked and speared fish during the later stages of the fight, adding to the difficulty in landing them. The majority of dogtooth tuna captures have tended to be made by trolling with dead and live baits or with lures, particularly deep-swimming plugs. [8]
These techniques are still often used, with one niche specialty being the use of live bait such as rainbow runners to tease dogtooth tuna within range of light tackle and fly-casting anglers. High speed jigging with a variety of metal lures has increased tremendously in popularity in the last several years as advancements in tackle technology have resulted in lightweight rods and reels that are capable of handling heavy spectra-type braided lines. Some of the more popular destinations for anglers seeking this species include Okinawa and other islands of southern Japan, Rodrigues and other Indian Ocean islands such as the Maldives, Andaman & Nicobar Islands, Bali and elsewhere in Nusa Tenggara in Indonesia, the Great Barrier Reef and its outlying atolls, and many Western Pacific islands such as Vanuatu, Fiji, Tonga, Samoa and Palau.
Trolling is a method of fishing where one or more fishing lines, baited with lures or bait fish, are drawn through the water. This may be behind a moving boat, or by slowly winding the line in when fishing from a static position, or even sweeping the line from side-to-side, e.g. when fishing from a jetty. Trolling is used to catch pelagic fish such as salmon, mackerel and kingfish.
Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment.
Big-game fishing, also known as offshore sportfishing, offshore gamefishing or blue-water fishing, is a form of recreational fishing targeting large game fish, usually on a large body of water such as a sea or ocean.
The king mackerelsurmayi or kingfish, is a migratory species of mackerel of the western Atlantic Ocean and Gulf of Mexico. It is an important species to both the commercial and recreational fishing industries.
The yellowfin tuna is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide.
Wahoo is a scombrid fish found worldwide in tropical and subtropical seas. It is best known to sports fishermen, as its speed and high-quality flesh makes it a prized and valued game fish. In Hawaii, the wahoo is known as ono. The species is sometimes called hoo in the United States.
The skipjack tuna is a medium-sized perciform fish in the tuna family, Scombridae, and is the only member of the genus Katsuwonus. It is otherwise known as the balaya, bakulan/kayu, tongkol/aya, aku (Hawaii), cakalang (Indonesia), katsuo, arctic bonito, mushmouth, oceanic bonito, striped tuna or victor fish. It grows up to 1 m (3 ft) in length. It is a cosmopolitan pelagic fish found in tropical and warm-temperate waters. It is a very important species for fisheries.
The double-lined mackerel, is a species of Spanish mackerel in the family Scombridae. This species is sometimes also called the scad mackerel.
The billfish are a group of saltwater predatory fish characterised by prominent pointed bills (rostra), and by their large size; some are longer than 4 m (13 ft). Extant billfish include sailfish and marlin, which make up the family Istiophoridae; and swordfish, sole member of the family Xiphiidae. They are often apex predators which feed on a wide variety of smaller fish, crustaceans and cephalopods. These two families are sometimes classified as belonging to the order Istiophoriformes, a group which originated around 71 million years ago in the Late Cretaceous, with the two families diverging around 15 million years ago in the Late Miocene. However, they are also classified as being closely related to the mackerels and tuna within the suborder Scombroidei of the order Perciformes. However, the 5th edition of the Fishes of the World does recognise the Istiophoriformes as a valid order, albeit including the Sphyraenidae, the barracudas.
Marlin fishing or billfishing is offshore saltwater game fishing targeting several species of fast-swimming pelagic predatory fish with elongated rostrum collectively known as billfish, which include those from the families Istiophoridae and Xiphiidae (swordfish). It is considered by some fishermen to be a pinnacle of big-game fishing, due to the size, speed and power of the billfish and their relative elusiveness.
The African pompano, also known as the pennant-fish or threadfin trevally, is a widely distributed species of tropical marine fish in the jack family, Carangidae. The species is found in tropical waters worldwide, with adults often inhabiting coastlines, while juveniles are usually pelagic, floating with ocean currents. The adult African pompano is similar in appearance to the other members of the genus Alectis, with the concave shape of the head near the eyes; the clearest distinguishing feature. The juveniles are similar to other members of Alectis, having long, filamentous dorsal and anal fin tips which are thought to discourage predators. The species lives in depths less than 100 m, consuming a range of crustaceans and small fishes. The species is of minor economic importance, often taken amongst other tropical midwater fishes by hook and line, while juveniles are occasionally caught in beach seines. African pompano are also highly rated game fish, often considered one of the strongest of the jacks in larger sizes.
The little tunny, also known as the false albacore, little tuna, bonita, or erroneously as the blue bonito, is a species of tuna in the family Scombridae. It can be found in the Atlantic Ocean and the Mediterranean and Black seas; in the western Atlantic, it ranges from Brazil to the New England states. The little tunny is a pelagic fish that can be found regularly in both offshore and inshore waters, and it is classified as a highly migratory species. The little tunny is best identified by the "worm-like" markings on its back and the dark spots appearing between its pectoral and ventral fins.
The rainbow runner, also known as the rainbow yellowtail, Spanish jack and Hawaiian salmon, is a common species of pelagic marine fish of the jack family, Carangidae. The species is widespread throughout the tropical and subtropical waters of the world, inhabiting both coastal and offshore areas. The species is the only member of the genus Elagatis, which was created 15 years after its initial description, and is closely related to the amberjacks. The rainbow runner is easily distinguished by its body shape, and the brilliant colouration which gives the fish its name. It is a fast-swimming predator, taking small fish, cephalopods, and a wide variety of planktonic crustaceans. The species reaches sexual maturity around 60 cm (24 in), and spawning takes place at different times, with some populations spawning year round, while others only spawn at certain times of the year. The species is a well known game fish, taken by a variety of fishing methods, and is a well-regarded table fish. Large numbers of the species are taken as bycatch in tuna- and shark-fishing operations and marketed.
Land-based game fishing is a form of big-game sport fishing in which anglers attempt to catch oceanic game fish from shore rather than from ocean-going boats. The locations for such activities are generally rock platforms, though wharfs, jetties and beaches are also common. Some species such as sharks can be targeted in shallow littoral water, however most other species prefer deeper pelagic water, and this limits the areas where these types can be fished from the shore. Tackle used is usually comparable to that used on boats, but some differences are necessary, such as changes in rod length. Different tackle is used according to location and species targeted.
The green jack, also known as the horse jack, is an abundant species of coastal marine fish in the jack family Carangidae. The species is distributed in the eastern Pacific Ocean along the American coastline from Santa Cruz Island off California in the north to Peru in the south, as well as a number of islands including the Galapagos and recently, Hawaii. The green jack is distinguished from other similar carangid species by a number of features including gill raker and lateral line scale counts, and the presence of an adipose eyelid. It is a moderately large species, growing to at least 55 cm in length and 2.81 kg, although unconfirmed reports suggest a much larger maximum size. It lives in a wide range of continental shelf environments including estuaries, bays, reefs and offshore seamounts, living both pelagically and demersally. The green jack is a predatory species, preying on a variety of fish, crustaceans and cephalopods, as well as zooplankton. Most fish are sexually mature by the time they attain 38 cm, with spawning occurring between May and October. The species is of high importance to fisheries throughout its range, caught by pelagic trawls, a variety of netting methods and hook and line. The green jack is also of interest to anglers, taken by bait and lures, although is considered to only be fair in eating quality.
The fishing industry in the Maldives is the island's second main industry. According to national tradition in the words of former President Maumoon Abdul Gayoom, "Fishing is the lifeblood of our nation, it is inborn. From the soil on which we live, to the sea around us, it remains an integral part of our existence. Fishing, and our country and its people, [are] one and shall remain inseparable forever." The Maldives has an abundance of aquatic life and species of fish. Common are tuna, groupers, dolphin fish, barracuda, rainbow runner, trevally and squirrelfish and many more. Aside from being of essential importance to the economy, fishing is also a popular recreational activity in the Maldives, not only among locals but by tourists. The islands have numerous fishing resorts which cater for these activities.
The houndfish is a game fish of the family Belonidae. It is the largest member of its family, growing up to 5 feet (1.5 m) in length and 10 pounds (4.5 kg) in weight. It is also often called the crocodile needlefish.
The longfin crevalle jack is a recently described species of large marine fish classified in the jack family, Carangidae. It inhabits the subtropical waters of the east Atlantic Ocean, ranging along the African coast from Mauritania south at least to Moçamedes in southern Angola, with the species historically present in the Mediterranean Sea. It is an inshore species, known to occasionally penetrate estuaries, possibly to spawn. The species is very similar to the crevalle jack, Caranx hippos, and is separated by its extended dorsal and anal fin lobes as well as more detailed anatomical features including dorsal and anal fin ray counts. The fish is known to reach 127 cm in length and 20.9 kg in weight. The longfin crevalle jack is a predatory fish, taking small fish as its main prey. Due to longstanding confusion between C. fischeri and C. hippos, the importance of each species to African fisheries is poorly understood, with a known combined catch in this region of between 2,233 and 10,054 tonnes per year in 1995–2004. Like its close relatives, the species is considered a powerful gamefish and highly sought after, although their coarse flesh makes for relatively poor quality food.
Mahi-mahi are swift and acrobatic game fish with striking colours. These colours darken when the fish dies The current IGFA all tackle record is 39.91 kilograms (88lb), caught in 1998 in Exuma, Bahamas by Chris Johnson of Lake Mary, Florida. Catches average 7 to 13 kilograms, and any mahi-mahi over 18 kilograms (40 lb) is exceptional. Males are often larger than females.
The blacktip trevally, also known as the blacktip kingfish or yellowtail kingfish, is a species of large marine fish classified in the jack family Carangidae. The blacktip trevally is distributed throughout the tropical to subtropical Indian and West Pacific Oceans, ranging from South Africa in the west to Fiji, Japan and northern Australia in the east. It inhabits coastal waters throughout its range, preferring moderately deep clear waters over rocky and coral reefs. The blacktip trevally is easily distinguished by its yellow fins and a dark upper caudal fin lobe which gives the species its common name, as well as a host of other anatomical features. The species is known to reach a maximum size of 1 m. It is a benthopelagic predator, commonly forming small shoals where it takes a variety of fishes, cephalopods and crustaceans as prey. Little is known of reproduction in the species, and spawning is assumed to take place in more tropical regions of its range, with juveniles known to inhabit bays and large estuaries. Blacktip trevally are often caught using hook and line and various nets in commercial fisheries although don't make up a large part of the market. They are also popular with anglers due to their fighting ability and decent table qualities.
