Tuna are great fun to catch and we all know how delicious they are to eat.
Tunas are fast swimmers—they have been clocked at 45 miles per hour —and include several species that are warm-blooded. Unlike most fish species, which have white flesh, tuna have flesh that is pink to dark red. The red coloring comes from tuna muscle tissue's greater quantities of myoglobin, an oxygen-binding molecule. Some of the larger tuna species, such as the bluefin tuna, can raise their blood temperature above that of the water through muscular activity. This ability enables them to live in cooler waters and to survive in a wide range of ocean environments.
Obviously the ability to live in cooler waters does not affect the fish we encounter here in Panama. We run into several varieties of tuna here in Panama.
Yellowfin
Yellowfin tuna is one such variety. It is found in open waters of tropical and subtropical seas worldwide. It is an epipelagic fish ranging in the top 330 feet of the ocean. Reported sizes have ranged as high as 94 inches in length and 440 pounds in weight. Also known as ahi tuna, from its Hawaiian name ʻahi, yellowfin is becoming a popular replacement for the severely depleted supplies of bluefin tuna.
The second dorsal fin and the anal fin are both bright yellow, thus the common name, and can be very long in mature specimens, as are the pectoral fins. The main body is very dark metallic blue, changing to silver on the belly, which has about 20 vertical lines.
Yellowfins tend to school with fishes of the same size, including other species of tuna, and larger fish are often seen with dolphins, porpoises, whales and whale sharks. Yellowfins eat other fish, crustaceans, and squid.
Blackfin
Blackfin tuna is the smallest tuna species, generally growing to a maximum of 39 inches in length and weighing 46 pounds. Blackfin have football shaped bodies, black backs with a slight yellow on the finlets, and have yellow on the sides of their body. Blackfin are only found in the western Atlantic from Cape Cod to Brazil.
This tuna does not consume as much fish in its diet than other tunas and will actually eat the tiny larvae of stomatopods (king shrimp or mantis shrimp), true shrimp, and crabs, as well as fish larvae. It does, of course, also eat juvenile and adult fish and squid. They are a short-lived, fast-growing species; a 5 year old fish would be considered old. They reach sexual maturity at two years old and spawn in the open sea during the summer. Blackfin tuna are a warmer-water fish, preferring water temperatures over 68°F (20°C). What they lack in size, they make up for in numbers and willingness to bite.
Tunas are fast swimmers—they have been clocked at 45 miles per hour —and include several species that are warm-blooded. Unlike most fish species, which have white flesh, tuna have flesh that is pink to dark red. The red coloring comes from tuna muscle tissue's greater quantities of myoglobin, an oxygen-binding molecule. Some of the larger tuna species, such as the bluefin tuna, can raise their blood temperature above that of the water through muscular activity. This ability enables them to live in cooler waters and to survive in a wide range of ocean environments.
Obviously the ability to live in cooler waters does not affect the fish we encounter here in Panama. We run into several varieties of tuna here in Panama.
Yellowfin
Yellowfin tuna is one such variety. It is found in open waters of tropical and subtropical seas worldwide. It is an epipelagic fish ranging in the top 330 feet of the ocean. Reported sizes have ranged as high as 94 inches in length and 440 pounds in weight. Also known as ahi tuna, from its Hawaiian name ʻahi, yellowfin is becoming a popular replacement for the severely depleted supplies of bluefin tuna.
The second dorsal fin and the anal fin are both bright yellow, thus the common name, and can be very long in mature specimens, as are the pectoral fins. The main body is very dark metallic blue, changing to silver on the belly, which has about 20 vertical lines.
Yellowfins tend to school with fishes of the same size, including other species of tuna, and larger fish are often seen with dolphins, porpoises, whales and whale sharks. Yellowfins eat other fish, crustaceans, and squid.
Blackfin
Blackfin tuna is the smallest tuna species, generally growing to a maximum of 39 inches in length and weighing 46 pounds. Blackfin have football shaped bodies, black backs with a slight yellow on the finlets, and have yellow on the sides of their body. Blackfin are only found in the western Atlantic from Cape Cod to Brazil.
This tuna does not consume as much fish in its diet than other tunas and will actually eat the tiny larvae of stomatopods (king shrimp or mantis shrimp), true shrimp, and crabs, as well as fish larvae. It does, of course, also eat juvenile and adult fish and squid. They are a short-lived, fast-growing species; a 5 year old fish would be considered old. They reach sexual maturity at two years old and spawn in the open sea during the summer. Blackfin tuna are a warmer-water fish, preferring water temperatures over 68°F (20°C). What they lack in size, they make up for in numbers and willingness to bite.