The Dogtooth tuna is a large fish that resides in the Indian and Pacific Oceans.
Another name for the Dogtooth tuna is the White Tune. Alternatively, its scientific name is Gymnosarda unicolor.
It is a mix of mackerel and tuna with it’s distinct feature of huge teeth as compared to the other types of tuna species.
This fish has a torpedo-shaped body with a large head at the end. Their mouths display sharp, canine teeth for which they get their name.
They are an offshore species. Mostly, they reside around coral reefs. They travel alongside fish about their size and feed on smaller fish in the area living in the same water temperature.
Species Description
The Dogtooth tuna doesn’t have any scales. The body has two dorsal fins. One of which is spiny, and the other is softer. It also has a ventral fin on its underside. The average adult Dogtooth Tuna weighs 40 pounds.
This species will swim continuously with its mouth open. This feature forces water through its gills. The Dogtooth Tuna has a high oxygen requirement and a lot of muscle activity when it swims.
Its body has a unique system in which the liver and tail provide a counter-current temperature exchange. This exchange raises the tuna’s body temperature by six degrees Celsius to 12 degrees Celsius higher than the water temperature.
How to Identify
Perhaps the most defining feature of the Dogtooth Tuna is its 40 teeth. The upper and lower jaw carries 20 teeth apiece.
The skin of White tuna has counter-shaded skin. That means the back of the fish is lighter than the fish’s belly. Its back is usually darker blue or green color. The sides of the fish are silver, and it has a white belly.
History
You will usually find the White Tuna is schools of fish that are around the same size. They swim in schools to protect themselves against predators and for feeding.
The larger fish in these schools are generally more independent. You might find the White Tuna swimming alongside other sea life like the gray reef sharks.
World Record
A spearfisherman caught the world record for the largest Dogtooth Tuna in French Polynesia on September 18th, 2014. The fish weighed 109 kg or 240.3 lbs.
Life Cycle
The life cycle for the Dogfish Tuna usually begins between December and February. These are the summer months of the southern hemisphere.
Spawning begins when the large groups of males and females start releasing gametes into the water for fertilization.
After floating to the water’s surface, the eggs will hatch after a few days. These newborn larvae start as no more than a quarter-inch in size.
Dogfish Tuna reach sexual maturity around two to three years old.
Habitat
They reside offshore but often go near drop-offs and atolls. As a migratory species, they prefer water that is between 70-80 degrees Fahrenheit.
Often, you might find them in reef environments where smaller fish stay in the shallower areas. Their schools are typically smaller in size of up to about six in a school.
The Dogtooth tuna is an apex non-pelagic predators in its environment.
The Dogtooth Tuna resides primarily in the Indian and Pacific Oceans. You can also find them near Australia and East Africa. Other places include waters off the coast of Japan, The Philippines, and other Pacific Islands.
The only human-made habitat where they live is the National Marine Sanctuary of American Samoa in the Pacific.
Diet
Dogtooth tuna is a fast predator. When feeding, they can swim up to 50 miles per hour. Due to their temperature preference, they prefer fish and sea life at the same water temperature.
Dogtooth Tuna are aggressive and opportunistic predators. They feed on small schooling fish and squids. Usually, the diet consists of smaller fish that stay close to nearby reefs.
Typically these tuna prey on shoaling fish like herring, mackerel, cuttlefish, squid, and sprats.
Threats
This is a species that is both a commercial fish and a sport fish. However, the Dogfish tuna is not on the endangered list.
The greatest threat to the Dogfish Tuna is overfishing. Commercial net fishing poses a severe problem for them as they are extremely vulnerable to overfishing.
Other threats to the Dogfish tuna are climate change. Changing climates displace migratory fish as it causes changes in water pressure and temperature. Pollution is another threat to Dogfish tuna because it affects the fish they prey on.
The fish they prey on are affected by coral bleaching and warmer waters. Also, coastal development that leads to algal blooms and increased pollution is dangerous for White Tuna.
How to Catch
Most Dogtooth Tuna catches come from trolling using dead and live baits and also lures. You will particularly want to use deep-swimming plugs.
Natural baits such as black marlin or even lures for fish like wahoo or Spanish mackerel are good choices.
Reel anglers and spearfishermen are also common catchers of this fish. This tuna is also an incidental catch by anglers trolling game fish.
Where to Catch
As a popular game fish, many charter-fishing boats from Australia and other parts of the south pacific hunt the Dogtooth tuna.
You can find Dogtooth Tuna in many places all over the world. In addition to the previously mentioned Indian and Pacific Oceans, you can also find this fish in places near New Guinea, Tahiti, Pitcairn, Oeno Islands, and Marquesas.
They also reside on reefs near Anunu’s Island, Nafanua Bank, and Swains Island — this is where they are most plentiful.
At times, you might also find this fish further inland than in the oceans.
How to Eat
People go after the Dogtooth Tuna for its flaky white meat. In addition to many kinds of fish dishes, you can buy it canned or frozen.
Eating this tuna comes with a warning. Ciguatera Fish Poisoning in humans happens when humans eat subtropical and tropical finfish like White Tuna. This ailment is a naturally occurring toxin in an algae species. Not all fish in the same area are toxic.
Generally, symptoms are feelings of seasickness or hangover, and the symptoms will subside after several days.
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