Tuna fish
Why in News?
Tuna fish is in the news because the Indian Council of Agricultural Research-Central Marine Fisheries Research Institute (ICAR-CMFRI) has issued an official health and safety advisory reassuring consumers that tuna caught along the Indian coast is completely safe to eat and free of harmful parasite infestations.
Biological & Physical Characteristics
- Warm-Blooded Physiology: Unlike most fish, tuna are endothermic (warm-blooded). They possess a specialized network of blood vessels called the rete mirabile, which helps them retain metabolic heat and keep their core muscles significantly warmer than the surrounding seawater.
- The "Ferraris of the Ocean": Built entirely for speed, their sleek, torpedo-shaped bodies feature retractable dorsal and pectoral fins that minimize drag. Species like the yellowfin tuna can achieve explosive swimming bursts of up to 75 km/h (47 mph).
- Size Variance: The family encompasses 15 distinct species. They range from the tiny 4-pound bullet tuna to the massive Atlantic bluefin tuna, which can grow up to 10 feet in length and weigh over 1,500 pounds.
Diet & Role in the Ecosystem
- Apex Predators: Occupying the top tier of the marine food web, adult tuna are carnivores that hunt in schools.
- Prey: They feed heavily on smaller schooling baitfish (like sardines, herring, and mackerel), squid, and crustaceans.
- Carbon Carbon Regulation: Because of their immense biomass and size, healthy global tuna populations function similarly to marine megafauna (like whales), playing a vital role in helping the oceans absorb carbon and mitigate climate change.
- Open Ocean Dwellers: Tuna prefer the pelagic (open ocean) zones of tropical and temperate seas worldwide, rarely venturing into shallow coastal waters.
- Global Travelers: They are highly migratory. A Pacific bluefin tuna can navigate an entire trans-Pacific journey of 8,000 kilometers in less than two months.
Commercial and Global Value
- Major Global Commodity: Tuna accounts for roughly 8% of all globally traded fish and makes up about 20% of the total economic value of all marine capture fisheries.
- The Canning Industry Evolution: Canned tuna originally surged during the mid-20th century, notably during World War II, when the US military relied on it as a crucial, shelf-stable, protein-dense military resource for troops overseas. Today, Skipjack tuna remains the most dominant species driving the global canned seafood industry.
