How do tuna mate

Food Habits Bluefin exhibit different feeding strategies, dependent upon their targeted prey. Bluefin feeding near shore have been recorded to eat starfish, kelp, and smaller shallow water fishes.

Bluefin are less likely to feed during the spawning season, when the majority of their activity must be dedicated to spawning activities. Their major competitors for food are marine mammals and other large fish, notably other scombrids and billfishes. Reproduction Bluefin tuna are oviparous.

In the Atlantic, spawning has been detected in only two areas: the Mediterranean and Gulf of Mexico. In the Pacific, spawning occurs off the Philippines.

This is a limited spawning area compared to other tropical tunas. Little is known about the spawning of bluefin, as it has not been observed. Differences in timing could be due to any of a number of factors, such as differing environmental cues or genetic variation.

In the Gulf of Mexico, spawning occurs at temperatures of In captivity, bluefin tuna have reached sexual maturity at 3 years, however others have suggested that bluefin become sexually mature at an age 4 to 5 years. Average females produce up to 10 million eggs per year. Their eggs are buoyant, and are distributed a considerable distance by the surface currents. The larvae hatch at a size of 3. They have large heads and large jaws, and lack body pigmentation.

Larvae of Thunnus species are very difficult to distinguish from one another, however bluefin are the only Thunnus species to have dorsal tail pigment. In spawning areas, larval abundance ranges from 0. The young, up to a size of 90 to lbs. These schools often consist of multiple species, possibly containing albacore, yellowfin, bigeye, skipjack, frigate tuna, bonito, and yellowtail. Predators Marine mammals, including killer whales and pilot whales, feed on the bluefin tuna.

Other predators include sharks, other large predatory fishes, and seabirds. Parasites The bluefin tuna is a host to 72 known parasites out of which 9 are host-specific. Copepods are among the parasites of this tuna including Caligus bonito and C. Euryphorus brachypterus is found on the wall of the branchial cavities and Brachiella thynni is parasitic on the fins. Other parasitic copepods include Pennella filosa which inserts itself into the flesh of the fish and Pseudocycnus appendiculatus found on the gill filaments.

Other parasites associated with this tuna include protozoans, digenea flukes , didymozoidea tissue flukes , monogenean gillworms , cestoda tapeworms , nematoda roundworms , acanthocephala spiny-headed worms , and copepods.

The cookiecutter shark Isistius brasiliensis , largetooth cookiecutter shark Isistius plutodus , and pilotfish Naucrates ductor are fish considered to be parasites of the bluefin tuna.

The bluefin tuna was first described by Linnaeus in as Scomber thynnus. A variety of names followed, including Thynnus thynnus , Thunnus vulgaris , and Albacora thynnus. In , Jordan and Evermann first allocated the tuna into the genus Thunnus , now the accepted name. This occurrence has caused great concern for the survival of this species. In the last few years, the sharp rise in the fleet has been encouraged by the expansion of bluefin tuna fattening cages in the Mediterranean and the increase in the fleets' capacity.

Bluefin tuna live mainly in the North Atlantic pelagic ecosystem and its adjacent seas, especially in the Mediterranean Sea. Geographically, their population is distributed throughout the North Atlantic, from Ecuador to Norway and from the Black Sea to Mexico.

Unlike other species of tuna, this is the only one that lives permanently in the temperate waters of the Atlantic. There are two independent populations or stocks of bluefin tuna: a lesser population in the western part of the Atlantic that spawns in the Gulf of Mexico, and a greater stock in the eastern part of the Atlantic, distributed in the East Atlantic, the Mediterranean and, in the past, the Black Sea, with the Mediterranean Sea as the spawning area.

In addition, it seems that bluefin tuna exhibit a behavior of returning to their birthplace and loyalty to the breeding grounds both in the Mediterranean and in the Gulf of Mexico. This implies that the adult and young specimens from both populations feed together, particularly off the coast of North America and in the mid-Atlantic.

Electronic marking studies have shown that the bluefin tuna is a highly migratory species that engages in two types of migration during its life: a trophic migration to seek food and another migration to spawn.

When the mating season begins, adults always return to the waters where they were born. Therefore, the adults born in the Gulf Mexico migrate to this area in the spring in order to spawn in April-May. Conversely, the adults born in the Mediterranean Sea return there when they reach maturity, at the end of spring, to spawn in June-July in the Western and Central areas. Bluefin tuna have a particularly well-developed circulatory system. This makes them warm-blooded fish and swift swimmers As other species of tuna and sharks, the Atlantic bluefin tuna is a pelagic predator that needs to swim continuously in order to ventilate itself and generate enough heat to maintain its vital organs and raise its body temperature above the water's.

Its circulatory system's complex structure enables it to minimize heat loss and maintain its internal body temperature above the sea water's. The bluefin tuna is a long-lived and slow growing species.

Bluefin tuna are usually between. They weigh on average between kg and kg Agustin, et al. Bluefin tuna larvae hatch at 3. They do have dorsal tail pigment. After hatching they grow 1 mm per day.

The young are on average 5. Growth is especially accelerated after 20 days after hatching, up to 2. Young begin schooling with other species of tuna based on size. Bluefin tuna form spawning aggregations. Males and females synchronously produce eggs and sperm milt , resulting in mating among many individuals at the same time. This is also called broadcast spawning. Bluefin tuna migrate to either the Gulf of Mexico or the Mediterranean and form spawning aggregations.

Females lay up to 10 million eggs each spawning period. Males fertilize the eggs as they are produced by the females. Water temperatures during spawning are Bluefin tuna become sexually mature between the ages of 4 and 8 years. No parental care is provided for the young. In the wild bluefin tuna are expected to live about 15 years. It is estimated that the longest lifespan known in the wild is between 20 and 30 years. Tuna caught and placed in captivity have short life spans because they are kept for a short period of time while they are fattened before harvesting.

Bluefin tuna display schooling behavior based on size not species. It is not uncommon to see many different species of similarly sized tuna in a school together. Schools migrate north during summer months along the coast of Japan and the west coast of the United States.

Trans Pacific migrations have been observed. Bluefin tuna have been known to cross the Atlantic Ocean in 60 days. Recent tagging data has shown that individual bluefin tuna frequently make several migrations from the eastern Atlantic to the western Atlantic and back again during the course of a year.

Bluefin tuna can swim up to Because they are capable of high speeds, they are very powerful predators. They form feeding aggregations throughout the Atlantic and Pacific when it is not spawning season.

The home rane of bluefin tuna is usually only limited to either the Atlantic Ocean or the Pacific Ocean. Individuals frequently migrate throughout the ocean in which they occur. For example, bluefin tuna have been observed to make several trips from the North American Atlantic coast to the European Atlantic coast and back again in a single year.

Bluefin tuna perceive their enviroment and communicate through visual and chemical cues. They also have a well-developed lateral line system. Bluefin tuna chase down their prey using their ability to swim at very high speeds.

They can also use modified filter feeding to catch small, slow moving organisms. They have also been known to eat kelp. They form feeding aggregations throughout the Atlantic and Pacific outside of the spawning season. Very little feeding occurs during spawning season.

Larvae feed on small organisms such as brine shrimp, other fish larvae, and rotifers. Juveniles also feed on small organisms until they become large enough to start feeding on small fish.