Atlantic Bigeye Tuna

Atlantic bigeye tuna

Thunnus obesus

ALSO KNOWN AS:

    Tuna, Big Eye, Ahi-b

SOURCE:

    U.S. wild-caught from Massachusetts to Florida
 

STATUS

  • POPULATION
  • FISHING RATE
  • HABITAT IMPACTS
  • BYCATCH
 

Click the icons to learn more about each criteria

 
 

OVERVIEW

Atlantic Bigeye Tuna

Measuring a bigeye tuna.

LAUNCH GALLERY

Bigeye tuna is a “highly migratory species” – these fish are found around the world and can travel across an entire ocean. Unlike non-highly migratory species that are only found off our coasts, U.S. fishermen aren’t the only ones fishing for highly migratory species such as bigeye tuna. Fisheries for these species require cooperative international management to ensure the resource is abundant and global harvests are sustainable. Although NOAA Fisheries is responsible for managing our domestic fisheries for bigeye tuna in the Atlantic, the United States is also a member of the International Commission for the Conservation of Atlantic Tunas (ICCAT) and negotiates with other member nations to enhance international management of bigeye tuna (along with other tunas, billfish, and sharks). With international cooperation to limit catches and protect undersized bigeye, the Atlantic bigeye tuna stock is increasing in size and approaching sustainable levels.

Bigeye tuna isn’t a major focus of U.S. commercial tuna fisheries in the Atlantic – annual bigeye harvests only make up about 15 percent of all Atlantic tunas landed by U.S. fishermen and less than 1 percent of the Atlantic bigeye tuna harvested worldwide. Almost all of the U.S. commercial harvest of bigeye tuna comes from the Pacific. A small amount of the  Pacific bigeye tuna caught in the United States is exported, while the remainder only makes up around half of the bigeye tuna eaten in the United States. The rest comes from imports, mainly from Asia, South America, and Central America.

Looking Ahead

The Atlantic bigeye tuna stock is currently being harvested at sustainable levels. However, managers and scientists are still concerned about the high levels of juvenile bigeye tuna catches in certain fisheries. There is particularly concern regarding tropical tuna fisheries around fishing aggregating devices (FADs), floating objects that are designed and strategically placed to attract pelagic fish. In 2013, ICCAT adopted a measure to expand reporting requirements for tropical tuna fisheries using FADS. The measure will improve data collection and allow ICCAT scientists to better characterize the fishing effort associated with FAD fishing. Strong international cooperation is needed for appropriate management and conservation of this fishery resource.

 
 
 

LOCATION & HABITAT

Bigeye tuna live in the tropical and warm temperate waters of the Atlantic, Pacific, and Indian Oceans. In the western Atlantic, they live from Southern Nova Scotia to as far south as Brazil.

Bigeye tuna are a pelagic species – they live at or near the surface to about 800 feet deep, deeper than other tropical tunas. Larvae are found in tropical waters, and as juvenile fish grow larger they tend to move into temperate waters. Bigeye tuna are a highly migratory species, swimming long distances throughout the ocean. They often swim in schools that dive into deeper waters during the day. They sometimes school with yellowfin and skipjack tunas at the surface, especially in warm waters.

 
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BIOLOGY

Bigeye tuna grow relatively fast, up to 5 ½ feet long, and live up to 9 years. Bigeye tuna are able to reproduce when they reach 3 ½ years old. They spawn in tropical waters throughout the year but most often during the summer. They usually spawn at least twice a year. Females release between 3 million and 6 million or more eggs each time they spawn.

Bigeye tuna feed near the top of the food chain on many aquatic species, such as fish, cephalopods, and crustaceans. They’re prey for top predators such as sharks, large billfish, and toothed whales.

 
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PHYSICAL DESCRIPTION

Bigeye tuna are dark metallic blue on the back and upper sides and white on the lower sides and belly. The first fin on their back is deep yellow, the second dorsal and anal fin are brownish or yellowish with narrow black edges, and the finlets are bright yellow with broad black edges. Their bodies are stocky and robust, and their eyes are large (thus the name bigeye).

Bigeye and yellowfin tuna look fairly similar, and it can be hard to distinguish between juveniles of the two species. Among other distinguishing characteristics, bigeye’s eyes are larger than the yellowfin’s and their finlets have black edges.

 
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OVERVIEW

The International Commission for the Conservation of Atlantic Tunas (ICCAT) assesses the abundance of Atlantic bigeye tuna and evaluates the sustainability of current and proposed harvest practices. They use the scientific information from these assessments to make management recommendations. The last ICCAT assessment was in 2010.

 
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POPULATION STATUS

Atlantic bigeye tuna has been managed under a rebuilding plan since 1999. In 2010, scientists estimated that the Atlantic bigeye tuna stock is not overfished but is still rebuilding to the target population level.

 
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Harvesting Bigeye Tuna

Bigeye tuna are highly migratory, traveling throughout large areas of the ocean. They are harvested by many nations using different types of fishing gear. U.S. commercial fishermen mainly harvest bigeye tuna using pelagic longlines. They sometimes use rod and reel gear.

Although neither pelagic longlines nor rod and reel gear  has an impact on habitat, pelagic longlines can incidentally catch protected species such as marine mammals and sea turtles. U.S. commercial fishermen using pelagic longline gear reduce bycatch by:

  • Using large circle hooks and certain types of bait that limit gear interactions with sea turtles. Circle hooks are designed to minimize injury, giving animals that are captured and released a better chance at survival.
  • Using special techniques to safely dehook and disentangle unintentionally caught turtles.
  • Removing gear from the water and moving one nautical mile if they encounter a protected species.
  • Limiting the length of their lines to 20 nautical miles and posting marine mammal handling/release guidelines on their vessels in the Mid-Atlantic Bight to protect pilot whales and Risso’s dolphins. In addition, if fishing in the Cape Hatteras Special Research Area, pelagic longline fishermen must contact NOAA Fisheries at least 48 hours prior to a trip and carry observers if requested.
  • Using weak hooks to reduce accidental catch of bluefin tuna and not using live bait in order to reduce bycatch of billfish in the Gulf of Mexico.
  • Closing areas in the Gulf of Mexico and seasonal areas in the Atlantic.
  • Carrying vessel monitoring systems (satellite technology) onboard their boats to enforce no fishing in closed areas.
  • Carrying at-sea fisheries observers on their vessels. NOAA Fisheries monitors the pelagic longline fishery and reviews observer data quarterly.

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Management

Who’s in charge? NOAA Fisheries Atlantic Highly Migratory Species Management Division. Also, because Atlantic bigeye tuna move throughout large areas of the Atlantic Ocean and are fished by many nations using various gear types, management by the United States alone is not enough to ensure that harvests are sustainable in the long term. The United States negotiates with regional fisheries management organizations, including the International Commission for the Conservation of Atlantic Tunas (ICCAT), to enhance tuna management worldwide. NOAA Fisheries sets regulations for the bigeye tuna fishery based on science and conservation and management recommendations from ICCAT.

Current management: Consolidated Atlantic Highly Migratory Species Fishery Management Plan
Domestic management measures for this fishery include permits, gear restrictions, time/area closures, and quotas. To provide additional protection to the bigeye tuna stock, particularly juveniles, bigeye tuna must be a minimum of 27 inches to be harvested in both commercial and recreational fisheries. This regulation is stricter than ICCAT requirements. Federal management for Atlantic tunas applies to state waters as well, except in Maine, Connecticut, and Mississippi. NOAA Fisheries periodically reviews these states’ regulations to make sure they’re consistent with federal regulations.

ICCAT conservation and management recommendations include an annual total allowable catch allocated among members, sharing arrangements for member countries, minimum size limits, effort controls, time/area closures, trade tracking requirements, compliance measures, and monitoring and inspection programs. ICCAT recommends adherence to an international cap on bigeye landings of 85,000 metric tons to allow the stock to continue to grow. ICCAT remains concerned about unreported catches and encourages tuna regional fishery management organizations to examine the possibility of “fish laundering” (reporting landings as another species) for bigeye and other species.

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Annual Harvest

U.S. harvest of Atlantic bigeye tuna is usually only a small fraction (1 percent or less) of the global Atlantic bigeye harvest. U.S. commercial fishermen landed about 869 metric tons of bigeye tuna in 2012.

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Economy

From 2005 to 2012, the average ex-vessel price (the price fishermen receive for their catch) of bigeye tuna increased about 30 percent. The ex-vessel price depends on a number of factors, including the quality of the fish (e.g., freshness, fat content, method of storage), the weight of the fish, the supply of fish, and consumer demand. In 2012, annual ex-vessel revenues for the fishery totaled more than $6.6 million.

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Recreational

Recreational fishermen also fish for bigeye tuna. They must have a permit to fish for bigeye and may only catch and keep bigeye tuna larger than 27 inches. Recreational fishing for highly migratory species such as bigeye tuna provides significant economic benefits to coastal communities through individual angler expenditures, recreational charters, tournaments, and the shoreside businesses that support those activities.

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OVERVIEW

Bigeye tuna meat has a reddish-pink color. It typically has a higher fat content than yellowfin and is preferred by sashimi lovers. The prices paid for both frozen and fresh product on the Japanese sashimi market are the highest of all the tropical tunas. Tropical tunas such as bigeye caught in the purse seine fishery are often canned as “light” tuna. Bigeye from other fisheries is sold fresh and frozen.

 
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SEASONAL AVAILABILITY

Year-round

 
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NUTRITION

Tuna is low in saturated fat and sodium and is a very good source of protein, thiamin, selenium, and vitamin B6.

Servings 1
Serving Weight 113 g
Calories 130
Protein 27 g
Fat, total 2 g
Saturated fatty acids, total 0.5 g
Carbohydrate 0 g
Sugars, total 0 g
Fiber, total dietary 0 g
Cholesterol 45 mg
Sodium 70 mg

Atlantic Bigeye Tuna Table of Nutrition

 
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RECIPES

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