Its population has declined by 58% and it is declining moderately rapidly due to excessive commercial fishing particularly by the EU nations which target the babies (under 6.4 lbs. They usually spawn two or more times a year. Bigeye Tuna (Thunnus obesus) Another species that is at risk of being endangered is the Bigeye tuna. Bigeye tuna spawn throughout the year but most often in the summer. They can live as long as 15 years. Bigeye tuna are generally the size of yellowfin, and smaller than bluefin. Bigeye tuna grow fast and can reach about 6.5 feet in length. Bigeye tuna spawn throughout the year in tropical waters and seasonally in cooler waters. Bigeye tuna (Thummus obesus) Bigeye tuna typically weighs 20–80 kg and is 90–180 cm in length (Figure 1e). They’re able to spawn almost daily, releasing millions of eggs each time.
Females release between 3 million and 6 million eggs each time they spawn. High values of genetic variability (mean number of alleles per locus and heterozygosity) characterized all studied locations. Genetic variation and population structure of Atlantic bigeye tuna. Thus, it creates some overfishing in certain population. The region’s most recent assessment of bigeye tuna confirms that less than 20 percent of the population remains.
). Bigeye tuna grow fast and can reach about 5.5 feet in length. That’s a significant development, because fishing nations have agreed that a population size this low “represents an unacceptable risk” to the stock, scientist John Hampton, who leads the program that conducted the assessments, was quoted as telling the Pacific News Center .
They are long and streamlined, have dark metallic blue on their backs and upper sides, and are nearly white on their lower sides and belly. Similar to the Yellowfin tuna, the Bigeye also migrate during different seasons. World production of this fish during 1980–90 was approximately 200 000 MT annually. They can live up to 9 years and are able to reproduce when they are 3.5 years old. This species is distributed in tropical and subtropical seas but is absent from the Mediterranean.
Bigeye Tuna - Commercial overfishing of one of the world's most valuable fish has driven the Atlantic bigeye tuna population to an overfished state. 3. They are very large tuna fish that live in the tropical waters namely the Indian, Pacific and Atlantic oceans. They live 7 to 8 years and are able to reproduce when they are 3 years old.