California Department of Fish and Wildlife

Marine Sportfish Identification: Tuna & Mackerels

Last Updated October 17, 2013

Note: Please consult current fishing regulations for species presented in this booklet. To view information on safe fishing eating guidelines, please visit the OEHHA website.

Albacore | Bigeye Tuna |  Bluefin Tuna | Pacific Bonito | Pacific Mackerel | Skipjack | Yellowfin Tuna

Pacific Mackerel


Pacific mackerel
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Pacific mackerel

 

Family: Scombridae (Mackerels and Tunas)

Genus and Species: Scomber japonicus

Description: The body of the Pacific mackerel tapers at both ends, is rather elongate, and somewhat compressed. The head is pointed and the mouth is large. The head is dark blue, the back is dark blue with about 30 dark wavy lines, and the undersides are silver green. The widely separated first and second dorsal fins serve to distinguish Pacific mackerel from all of the other tuna-like fishes that inhabit our waters, except for the frigate and bullet mackerel. Pacific mackerel and bullet mackerel can be differentiated by counting the dorsal finlets. Pacific mackerel typically have four to six, while bullet and frigate mackerel have seven to eight finlets.

Range: Worldwide in temperate seas; in the eastern Pacific from Chile to the Gulf of Alaska.

Natural History: Larval, juvenile or small fishes appear to be the most important natural food of Pacific mackerel, but there are times when they rely heavily on small crustaceans. They feed upon squid to a lesser extent, and eat whatever other bite-sized organisms they may encounter. Off southern California, spawning normally reaches a peak during the early spring months, especially March, April and May. Pacific mackerel eggs are about 0.045 inch in diameter and float free in the upper layers of the ocean, usually within 300 feet of the surface. At average water temperatures they will hatch 4 or 5 days after being spawned.

Fishing Information: Pacific mackerel have long been cast in the role of an intruder or nuisance fish by most anglers, especially those seeking larger sportfish like yellowtail or barracuda. Nevertheless, they have been the most frequently caught species on hook and line in California waters in recent years. Known as a voracious, indiscriminant feeder, Pacific mackerel will devour a live anchovy, engulf dead cut bait, strike readily on lures and often on flies. While it is relatively small in size (2 pounds or 16 inches would be trophy size), it scores high for power (ounce for ounce) and beauty. Pacific mackerel put up an excellent fight against light tackle.

Other Common Names: American mackerel, blue mackerel, greenback jack, chub mackerel.

Largest Recorded: 25 inches; 6.3 pounds.

Habitat: Pelagic Environment

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Skipjack


Skipjack
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Skipjack

 

Family: Scombridae (Mackerels and Tunas)

Genus and Species: Euthynnus pelamis

Description: The body of the skipjack is cigar-shaped (tapers at both ends). The snout is sharply pointed and the mouth is relatively large. The color is dark blue to purple on the back become silvery or white below, with four to six dark horizontal stripes on the belly.

Range: Skipjack occur worldwide in warm seas. They are found in the eastern Pacific from Peru to Vancouver Island, British Columbia. Skipjack usually visit California waters in the fall when water is relatively warm (about 68° F) and the currents are from either the south or southwest.

Natural History: The diet of the skipjack tuna includes fishes such as anchovies and sardines, as well as pelagic red crabs and squid. Skipjack tuna do not spawn in waters off California, but further south in the eastern Pacific, with spawning occurring during the summer months. Females mature at about 16 inches. Depending on size, females can produce between 100,000 and 2 million eggs per spawning event. Young fish grow rapidly reaching 12 inches by the time they are 1 year old. Maximum age is estimated to be 8 to 12 years.

Fishing Information: Most skipjack are taken incidentally to other fishing activities, especially albacore or tuna fishing. They bite a feather eagerly and will readily come to the boat when live anchovies are used as chum. Most anglers do not actively seek skipjack because of their small size and the undesirability of the meat when fresh. However, skipjack is good if processed and most is consumed after it is canned. Most skipjack taken off California weigh 3.5 - 6.5 pounds, and are 18 to 22 inches.

Other Common Names: skippies, oceanic bonito, striped tuna, arctic bonito, watermelon, victor fish.

Largest Recorded: The maximum reported length of a skipjack tuna is about 3.7 feet; the maximum weight is about 74 pounds. In California, the angling record stands at 26 pounds (no length).

Habitat: Pelagic Environment

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Pacific Bonito


Pacific Bonito
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Pacific Bonito

 

Family: Scombridae (Mackerel and Tunas)

Genus and Species: Sarda chiliensis

Description: The body of the Pacific bonito is cigar-shaped and somewhat compressed. The head is pointed and conical, and the mouth is large. The color is dark blue above, dusky on the sides becoming silvery below. There is a number of slanted darkish stripes along the back. Pacific bonito are the only tuna-like fishes on the California coast that have the slanted dark stripes on their backs.

Range: Pacific bonito occur discontinuously from Chile to the Gulf of Alaska, with the greatest area of abundance in the northern hemisphere occurring in warm waters between Magdalena Bay, Baja California, and Point Conception, California.

Natural History: The preferred food of bonito appears to be small fishes, such as anchovies and sardines. Occasionally, they rely heavily upon squid in their daily diet. Bonito may not spawn successfully every year in California, but successful spawning does take place further south each year. The bulk of southern California spawning appears to take place from late January through May. The free floating eggs require about 3 days to hatch at average spring water temperatures. Young fish resulting from local successful spawnings are usually first observed by the various live bait haulers when they are 6 to 10 inches long in the early summer months. These fish will often weigh 3 pounds or more by the fall of the year and by May of the following year many will weigh 6 or 7 pounds.

Fishing Information: Pacific bonito are excellent fighters and have hearty appetites. Once a school is aroused they will take almost any bait or lure that is tossed their way. Most Pacific bonito are taken by a combination of trolling and live bait fishing. The schools are located by trolling feathers, and live anchovies or squid pieces are used to bait the fish once located. Fishing for bonito generally takes place offshore in 300 to 600 feet of water, but may occur next to kelp beds when the fish are near shore. Pacific bonito may arrive off of California as the ocean warms in the spring, but may never show up if oceanic conditions dictate colder than normal water temperatures. Bonito anglers generally catch 1 to 4 year old fish, weighing between 3 and 12 pounds. Pacific bonito fishing tapers off in the fall as the water cools, but persistent anglers still find good bonito fishing around warm water outfalls associated with power plants.

Other Common Names: bonehead, Laguna tuna, magneto, striped tuna, California bonito, ocean bonito.

Largest Recorded: 40 inches; 25 pounds.

Habitat: Pelagic Environment

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Albacore


Albacore
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Albacore

 

Family: Scombridae (Mackerels and Tunas)

Genus and Species: Thunnus alalunga

Description: The body of the albacore tapers at both ends (cigar-shaped). The head is long and the mouth fairly large. The color is dark gray to metallic blue on the back becoming white to gray below. Albacore are easily distinguished from the other tunas occurring off California, with exception of the bigeye, by the extreme length of their pectoral fins (they extend well past the anal fin). Albacore and bigeye can best be distinguished by the characteristics of their livers. The albacore has a heavily striated (covered with blood vessels) liver while the liver of the bigeye is only lightly striated along the edges.

Range: Albacore occur worldwide in temperate seas; in the eastern Pacific they range from south of Guadalupe Island, Baja California, to southeast Alaska.

Natural History: The food of the albacore varies, depending upon where they are feeding in the water column and what items are available at the time and place the albacore are feeding. A majority of the food consists of small fishes, but at times squid, octopus, shrimp-like and crab-like organisms are extremely important. There are indications that albacore spawning takes place in the mid-Pacific, probably north and west of the Hawaiian Islands. Large specimens caught in that area during late summer on long line gear have had nearly ripe eggs in their ovaries. The albacore is one of the world's fastest migrant fish. Annual trans-Pacific migrations have been documented by tagging. Fish tagged off California were captured off Japan, nearly 5,000 miles away, 294 days later. Traveling "as the crow flies", this is equivalent to more than 17 miles a day.

Fishing Information: Albacore are the most sought after of the tunas by California anglers. Most fishing for albacore takes place 20-100 miles offshore in central and southern California. They are rarely taken near shore. Albacore have a preference for deep blue oceanic water and mild temperatures. Studies indicate that 57 of every 100 albacore caught are hooked in water ranging in temperature between 60° and 64° F. Albacore travel in loosely knit schools which are located by trolling or observing surface signs (feeding birds, etc.). Once located, they are fished with hook and line using live anchovies for bait. They may also be caught on a trolled feathered jig.

Other Common Names: longfin, albie, pigfish, Pacific albacore, German.

Largest Recorded: 5 feet; 90 pounds (California).

Habitat: Pelagic Environment

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Bigeye Tuna


Bigeye Tuna
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Bigeye Tuna

 

Family: Scombridae (Mackerels and Tunas)

Genus and Species: Thunnus obesus

Description: The body of the bigeye tuna is cigar-shaped (tapered at both ends). The head is pointed and the eye is relatively large. The color is dark metallic brownish blue to dark yellow on the back becoming gray or whitish below. There often is a bluish stripe on the side. In most individuals, the length of the pectoral fins should enable one to identify the species properly. Both bigeye and yellowfin tuna look similar, but bigeye tuna have pectoral fins which extend well past their anal fin, while yellowfin tuna have much shorter pectoral fins. Tuna which cannot be distinguished by external characteristics can be positively identified by liver characteristics. Bigeye tuna livers are striated (covered with blood vessels) along the trailing edges, while yellowfin tuna livers are smooth. Small bigeye tuna also may be distinguished from albacore by the characteristics of the liver. The liver is heavily striated in the albacore while the bigeye tuna liver is only striated along the trailing edges.

Range: Bigeye tuna occur worldwide in warmer seas. In the eastern Pacific these tuna range from Peru to Iron Springs, Washington. They are occasional visitors to California, entering our fishing grounds in June and remaining until November. These fish prefer temperate water in excess of 70° F, but significant catches have occurred in water as cool as 65° F.

Natural History: The diet of bigeye tuna includes fishes, squid, and crustaceans. Like most other tunas, they feed on what is most abundant in the area. Bigeye tuna do not spawn in waters off California, but spawn further south in the Pacific. Bigeye tuna are approximately 3 years old at first spawning. In the equatorial regions of the Pacific, the peak spawning is between April and September. A bigeye tuna weighing 159 pounds will produce an estimated 3.3 million eggs per year. The young are fast growing and weigh about 45 pounds when they first mature. They live 7 or 8 years.

Fishing Information: Bigeye tuna generally are not accessible to recreational anglers because they travel far below the surface during the day. Only rarely are they seen on the surface, and then, only momentarily while feeding. This makes the fish hard to locate since they leave no telltale surface signs nor can they be easily located by trolling. Most bigeye tuna are taken incidental to albacore or marlin fishing. The best way to fish for them is to troll marlin lures in an area where the fish are known to occur. Most bigeye tuna taken in southern California weigh 50 to 100 pounds, with an occasional 150 to 200 pounder landed.

Other Common Names: gorilla, tuna, patudo.

Largest Recorded: 80 inches; 435 pounds; 240 pounds (California).

Habitat: Pelagic Environment

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Bluefin Tuna


Bluefin Tuna
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Bluefin Tuna

 

Family: Scombridae (Mackerel and Tunas)

Genus and Species: Thunnus thynnus

Description: The body of the bluefin tuna is cigar-shaped and robust. The head is conical and the mouth rather large. The color is dark blue above and gray below. Bluefin tuna can easily be distinguished from other members of the tuna family by the relatively short length of their pectoral fins. Their livers have a unique and definitive characteristic in that they are covered with blood vessels (striated). In other tunas with short pectoral fins, such vessels are either not present or present in small numbers along the edges.

Range: Worldwide in all but the coldest seas. Bluefin tuna range throughout the eastern North Pacific Ocean with fish being taken from Magdalena Bay, Baja California, to Shelikof Strait, Alaska. Most bluefin tuna landed by California anglers are 1 or 2 year olds and weigh between 15 and 30 pounds.

Natural History: Examination of a number of stomachs indicates that while in California waters anchovies make up the bulk of the diet. Sanddabs, surfperches, and white croakers are also consumed.

Fishing Information: Bluefin tuna are seasonal visitors to California waters. They usually appear in May and depart by October. Since they are temperate tunas, their availability to anglers depends on water temperatures in the 62° to 68° F degree range. They can be located by either trolling feathers or anchoring at a spot known to be frequented by bluefin tuna, and chumming with live anchovies.

Other Common Names: leaping tuna, tuna, footballs, tunny, shortfin tuna, ahi, great albacore.

Largest Recorded: No length recorded; 363.5 pounds (California). Weight to 495 pounds in the Pacific Ocean, and 1,500 pounds in the Atlantic Ocean.

Habitat: Pelagic Environment

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Yellowfin Tuna


Yellowfin Tuna
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Yellowfin Tuna

 

Family: Scombridae (Mackerel and Tunas)

Genus and Species: Thunnus albacares

Description: The body of the yellowfin tuna tapers at both ends (cigar-shaped), and the head is conical. The color is dark brownish blue to dark yellow on the back becoming gray or whitish below. Identifying tunas can be difficult, especially when yellowfin and bigeye tuna are involved. In most cases, the length of the pectoral fins can distinguish each species. The yellowfin has pectoral fins which do not extend past the anal fin; while in bigeye, the pectoral fins extend well past the anal fin. Tuna which cannot be distinguished by external characteristics can be positively identified by liver characteristics. The surface of a yellowfin's liver is smooth while the liver of the bigeye is striated, containing many with small blood vessels along the trailing edge.

Range: Widely distributed in the Pacific Ocean. In the eastern Pacific, yellowfin tuna occur from Chile to Point Buchon, California. They occasionally enter California waters when ocean temperatures are warm. They usually are not taken in waters less than 70° F with best catches occurring in waters above 74° F.

Natural History: The diet of the yellowfin tuna includes juvenile fishes, crustaceans, and squid. They are opportunistic feeders taking whatever is most available in the area. Yellowfin tuna do not spawn off the coast of California; however, they do spawn further south in the eastern Pacific. Some spawning takes place during every month of the year, but off Central America it peaks during January and February. Young fish grow very rapidly and by the time they are 1.5 years old they weigh around 7.5 pounds. At 4 years old they weigh approximately 150 pounds. The largest yellowfin tuna taken are 10 or more years old. These larger fish sometimes have an elongated second dorsal fin.

Fishing Information: Yellowfin tuna are fished in much the same manner as albacore; jigs are used to locate the schools, and live anchovies are chummed to keep the fish around the boat. Most yellowfin tuna taken in California weigh 30 to 50 pounds, fish over 200 pounds are occasionally landed. The smaller fish are 1 to 2 years old while the larger ones may be over 10 years of age.

Other Common Names: Allison tuna, ahi, Pacific yellowfin.

Largest Recorded: No length recorded; 239 pounds (California); weight to 450 pounds.

Habitat: Pelagic Environment