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Little tunny

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Little tunny
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Perciformes
Family:
Scombridae
Genus:
Euthynnus
Species:
E. alletteratus
Binomial name
Euthynnus alletteratus
(Rafinesque, 1810)

The little tunny (Euthynnus alletteratus) is the most common tuna in the Atlantic Ocean. It is found in warm temperate and tropical waters of the Atlantic and the Mediterranean; in the western Atlantic, it ranges from Brazil to the New England states. It is found regularly in offshore and inshore waters, and is classified as a highly migratory species by UNCLOS.[1] Occurring in large schools and weighing up to 35 pounds, it is the smallest member of the tuna Scombridae family, and is one of the finest small game-fish in the Atlantic.

Commonly called "false albacore" or "albie", it resembles the Atlantic bonito, skipjack tuna and species of mackerel.[2] The little tunny feeds primarily on pelagic fish. It is best identified by the dark spots appearing between its pectoral and ventral fins and "worm-like" markings on its back.[3] Commercially, the fish is used as bait for sharks and marlin due to its high oil content and hook retention. It is considered by many to be a trash fish because of its limited nutritional value; there have even been reports of ciguatera poisoning related to its consumption. However, the little tunny is commercially important in many locations including the West Indies. It is marketed fresh, dried, canned, smoked, and frozen.[4] It is sought after as a sport fish due to its line stripping 40 miles per hour (64 km/h) runs and hard fighting ability when hooked.

Taxonomy

Constantine Samuel Rafinesque identified the little tunny in 1810 and gave the fish its current name: Euthynnus alletteratus. The genus Euthynnus is derived from the Greek "eu", meaning good, and "thynnos" meaning tuna. Synonyms for used for the name include E. alleteratus alleteratus, E. alliteratus, E. thunina, and E. alletteratus aurolitoralis.[4] The little tunny is not part of the Thunnus genus like many tuna, but it is part of the same Scombridae family.[5]

Physical description

An image of a little tunny.
A little tunny.

The little tunny is small in body size compared to other tuna species. It has a compact and stream-lined body built to facilitate bursts of speed as well as endurance while swimming. It has a large mouth with a slightly protruding lower jaw, with a single row of small, inwardly curved teeth on the palatines. Teeth are absent on the vomer, the small bone in the roof of the mouth, and the tongue.[4] The snout is shorter than the rest of the head. The little tunny has a dorsal fin with 10 to 15 tall, descending spines, as well as a much smaller second dorsal fin followed by 8 finlets. The anal fin has 11 to 15 slightly defined rays, and is followed by 7 finlets. The pectoral fins are short and do not reach the end of the first dorsal fin and are joined to the pelvic fins by interpelvic processes.[4] There are 37-45 gill rakers on first arch. There are no scales on the body of the little tunny except along the lateral line and on the corselet: a thick band of scales circling the body.[4] The coloration of the little tunny is typically metallic blue or blue-green with dark wavy stripes above the lateral line. These "worm-like" lines never extend farther forward than the middle of the first dorsal fin. The belly is bright white with 3–7 dark, fingerprint-like spots around the pectoral and pelvic fins. The little tunny is commonly confused with the Atlantic bonito because of coloration, but the two fish differ in their color patterns and overall body size.

The little tunny's markings allow it to easily be distinguished from similar species. The little tunny is often confused with the skipjack tuna, the frigate mackerel, the Atlantic bonito, and the bullet mackerel. Close relatives also include the kawakawa and the black skipjack. The scattering of dark, fingerprint-like spots between the pectoral and pelvic fins cannot be found on any related Atlantic species. The first dorsal fin of the Atlantic bonito is also lower and sloping. Its lack of teeth on the vomer can set it apart from its close Pacific relatives: the kawakawa and the black skipjack. The dorsal fins of the bullet and frigate mackerel are set apart. Unlike the little tunny, the skipjack tuna lacks markings on the back and has broad, straight stripes on the underside.[6]


Little tunny reach a maximum weight of 12 kilograms (26 lb) in the Mediterranean, and averages about 7 kilograms (15 lb) throught its entire range. The maximum fork length (distance from the tip of the snout to the fork of the tail) of the little tunny in the Mediterranean is about 100 centimetres (39 in) and in the Atlantic is about a 90 centimetres (35 in).[7] Average fork length for an adult fish throughout the entire range is about 85 centimetres (33 in) .[8] Some little tunnies may reach the length of 40 inches or more, but most commonly they are around 25 inches. The largest little tunny on record is 48 inches (120 cm) and 35.3 pounds (16 kg). Females reach sexual maturity at10.6 to 14.6 inches (27–37 cm) in fork length length while males mature at approximately 15.7 inches (40 cm).[4]

Anatomy

The little tunny has some anatomical variations when compared to other species of Euthynnus. E. alletteratus lacks a swim bladder, like most other tuna, so it must constantly keep moving to stay afloat. The pectoral fins are crucial to the little tunny in maintaining its position in the water column. The little tunny's liver is very disproportionate, with the right lobe much longer than the left or middle lobes. The stomach of the little tunny is a long sac that stretches almost the entire length of its body. The intestinal tract is fairly short, coming from the left and right sides of the stomach, and extending without looping down the length of the tuna's body. The different sections are characterized by their diameter and color.[9] The ventral vertebral column of the little tunny has unique trelliswork, which is important to its family (Scombridae.) Divided haemapophyses, or parts of the vertebrate, forming a long canal enclose the large ventral blood vessel.[10]

Feeding habits

A school of fish feeding at the surface.
A school of little tunny feeding.

In coastal waters along the North American eastern seaboard, little tunny are carnivorous, and primarily feed on small fish and invertebrates. Sardines, scad, and anchovies are common in the diet along with squid, stomatopods, and organisms from the diogenidae family. The little tunny primarily feeds on fishes and invertebrates that occur in schools. The diet of the fish is also relative to its size. A smaller fish's diet typically consists of clupeiform, and larvae, while the larger fish mostly eat maurolicus muelleri. The typical diet is very similar to that of the king mackerel because the fish are of a similar size and live in the same area of the water column. [2] It mostly feeds on pelagic fish. The little tunny is an opportunistic predator, feeding on crustaceans, clupeid fishes, squids, and tunicates. The Little Tunny's diet also responds to seasonal cahnges in food availability. It has been observed that the Little Tunny has nocturnal feeding habits, and are specialist feeders. It often feeds on herring and sardines in inshore waters near the surface of the water.[4] The little tunny commonly feeds in large schools because their primary food sources (small fish and the larval forms of crustaceans) are typically in schools as well.

Distribution and habitat

A global map showing the distribution of the little tunny: a solid bar exists across much of the Atlantic ocean (from Novia Scotia to southern England in the North and from Brazil to Angola in the south)
Range of the little tunny

The little tunny is found in the neritic waters of the temperate and tropical zones in the Atlantic ocean. It can also be found in the waters of the Mediterranean Sea and the Black Sea. In the eastern Atlantic, the little tunny has been found from Skagerrak to South Africa. Although found it this broad range of latitudes, it is rare north of the Iberian Peninsula or farther south than Brazil. On the Atlantic coast of the United States, they can be caught as far north as Cape Cod, Massachusetts, and as far south as the tip of Florida, as well as throughout the waters of the Gulf of Mexico.[11]

The little tunny's habitat tends to be near-shore waters, much closer to shore than most other tunas. They live in and around inlets, points, jetties, and sandbars. All of these places are where bait fish like sardine and menhaden, both favorites of the little tunny, form large schools, which are very helpful to the little tunny's feeding style. While the little tunny is abundant in offshore ocean waters, it is unusual to find it in brackish water of estuaries. The very young will enter estuaries in South Africa.[12] The little tunny prefers relatively warm water, from 24° to 30° Celsius. The little tunny migrates south in the winter and fall, and northward in the spring, through coastal waters. It is not as migratory as other tuna species.[13]


The little tunny is typically a schooling species.[14] It lives in schools based primarily on fish size rather than species, so other members of the Scombridae family, like the atlantic bonito, may be present. These schools cover areas up to 2 miles long. Little tunny that have not yet reached adulthood form tight schools offshore. Larger schools are more common offshore whereas smaller groups may wander far inshore.

Reproduction

Little tunny spawn in water that is at least 25 °C (77 °F) in the months of April through November in the Atlantic Ocean. The spawning season of the little tunny in the Mediterranean is generally between May and September, but the most intensive spawning occurs between July and August. The major spawning areas are offshore, in waters that are 100 to 130 feet deep. The females are prolific fish, and can release 1.75 million eggs, in multiple clutches over a mating season.[4] The eggs are fertilized in the water column after the males release sperm. The eggs are buoyant, spherical, transparent, and pelagic. A droplet of oil within the egg adds to its buoyancy. The diameter of the eggs can be anywhere from 0.8 mm to 1.1 mm, and they are light amber. Larvae are released 24 hours after fertilization and are approximately 3 mm in size. Pigmentation in the eyes appear 48 hours after hatching. The teeth and fins develop at sizes of 3.7–14 mm. Once the larvae are 14mm to 174mm long, they take on the adult appearance; the body becomes more elongated.[15] Studies have found that it takes approximately 3 years for the little tunny's gonads to reach sexual maturity. The average size of a sexually mature individual is 15 inches (38 cm) in fork length.[16]

Predators and parasites

Bony fish, Marlins, sea birds, sharks, and rays prey on the little tunny. [17] Other tunas, including conspecifics and yellowfin tuna (Thynnus albacares) are predators of the little tunny. Fish such as the dolphin fish (Coryphaena hippurus), wahoo (Acanthocybium solandri), Atlantic sailfish (Istiophorus albicans), swordfish (Xiphias gladius), and various sharks as well as other large marine carnivores all prey on the little tunny. Among those sharks is the whale shark, who feeds on the little tunny's recently spawned eggs. Seabirds prey on small little tunny.[4]

Parasites of the little tunny include the copepods Caligus bonito, Caligus coryphaenae, and Caligus productus, all found on the body surface as well as on the wall of the branchial cavities. Another copepod, Pseudocycnoides appendiculatus, has been documented as parasitic on the gill filaments. Other parasites include digenea (flukes), monogenea (gillworms), cestoda (tapeworms), and isopods.[4]

Fishing and preparation

Schools of little tunny are usually indicated by flocks of birds diving in coastal waters. Fishermen in charterboats and smaller boats often troll bait, cast lures, and float fish. When trolling for Little Tunny, fishermen often use small lures baited with either mullet or Ballyhoo. Also, when trolled at lower speeds, they use colored feathers for bait. When they float fish, they use live bait like Spot, Bluefish, or Pinfish. Live bait works better for attracting Little Tunny, as well as spoons of Jap feathers. Any Little Tunny under about 8 pounds, is good bait for Blue Marlin. Most Little Tunny that is caught, is usually used for strip bait or is thrown back. The Little Tunny is not thought of as a food fish, it is often known as a popular sport fish. Unlike most fish, the Little Tunny has no size or bag limits, and there is no closed season. The flesh of the Little Tunny is coarse in texture, strong in flavor, and dark in color if compared to bluefin or yellowfin tuna.[18]

As for preparation of the Little Tunny, as soon as it is caught, it should be bled and iced. There are many ways to eat the Little Tunny, one way is to prepare the fish for Tuna Salad. In doing this, the fillets are first baked, then chilled and flaked, then mixed in with the salad. Removing the dark strips of meats that extend the length of each fillet helps to reduce the naturally fishy flavor. [19] Another way to prepare the Little Tunny is first to bleed it, then barbeque it in foil. Once you've done that, you remove the meat from the bone, and let it chill overnight. Adding Italian to it will also help enhance the flavor.

References

Footnotes
  1. ^ Majkowski 2010 harvnb error: multiple targets (2×): CITEREFMajkowski2010 (help)
  2. ^ a b Manooch 1985, p. 1207
  3. ^ Schultz 2004, p. 259 harvnb error: multiple targets (2×): CITEREFSchultz2004 (help)
  4. ^ a b c d e f g h i j Bester 2010
  5. ^ GoFISHn, 2011, retrieved 4 January 2011
  6. ^ GoFISHn, 2011, retrieved 4 January 2011
  7. ^ Macías 2008, p. 2 harvnb error: multiple targets (2×): CITEREFMacías2008 (help)
  8. ^ Valeiras 2006, p. 233 harvnb error: multiple targets (2×): CITEREFValeiras2006 (help)
  9. ^ Godsil 1954, p. 141 harvnb error: multiple targets (2×): CITEREFGodsil1954 (help)
  10. ^
  11. ^ Richardson 2001, p. 78 harvnb error: multiple targets (2×): CITEREFRichardson2001 (help)
  12. ^
  13. ^ GoFISHn, 2011, retrieved 4 January 2011
  14. ^
  15. ^ Kahraman 2008, p. 551
  16. ^ Kahraman 2008, p. 552
  17. ^ Froese 2010
  18. ^ Romeo 1962, p. 257 harvnb error: multiple targets (4×): CITEREFRomeo1962 (help)
  19. ^ Manooch 1984, p. 200

http://www.ncfisheries.net/statistics/comstat/tunny.htm http://www.marinespecies.org/aphia.php?p=taxdetails&id=127017

http://www.marinespecies.org/aphia.php?p=taxdetails&id=127017

http://www.scialert.net/abstract/?doi=jfas.2011.256.263&linkid-abst

http://scialert.net/qredirect.php?doi=jfas.2011.256.263&linkid=pdf

http://icesjms.oxfordjournals.org/content/early/2007/05/26/icesjms.fsm065.full.pdf

Cited texts

  • Bester, Cathleen. "Little Tunny". Ichthyology Section. Florida Museum of Natural History. Retrieved 25 October 2010.
  • Falautano, M.; Castriota, L.; Finoia, M.G.; Andaloro, F. (21 November 2010) [2007], "Feeding ecology of little tunny euthynnus alletteratus in the central Mediterranean Sea", Marine Biological Association of the United Kingdom. Journal 87: 999–1005
  • Froese, R.; Pauly, D. (2010), FishBase, retrieved 5 December 2010


  • Macías, D. (2008), http://www.iccat.int/Documents/Meetings/Docs/SCRS/SCRS-08-189_Macias_et_alf.pdf (PDF), in D., Macías (ed.), SIZE DISTRIBUTION OF ATLANTIC LITTLE TUNA (Euthynnus alletteratus) CAUGHT BY SOUTH WESTERN SPANISH MEDITERRANEAN TRAPS AND RECREATIONAL TRAWL FISHER, Spanish Institute of Oceanography, Fuengirola, Spain: ICCAT, pp. 1–7, retrieved 2011-01-04 {{citation}}: |contribution-url= missing title (help); |format= requires |url= (help); Unknown parameter |coeditors= ignored (help)
  • Manooch, Charles S.; Mason, Diane L.; Nelson, Russell S. (22 October 2010) [1985], "Foods of Little Tunny Euthynnus alletteratus Collected along the Southeastern and Gulf Coasts of the United States", Bulletin of the Japanese Society of Scientific Information, 51 (8): 1207–1218
  • Manooch, Charles, Fisherman's Guide Fishes of the Southeastern United States, p. 200-201 {{citation}}: |access-date= requires |url= (help)
  • Richardson, Tom (2001). Inshore Salt Water Fishing: Learn from the Experts at Salt Water Magazine. Creative Publishing international, Inc. pp. 78–80. ISBN 0-86573-132-2.
  • Schultz, Ken (2004). "Little Tunny". Ken Schultz's Field Guide to Saltwater Fish. Hoboken, New Jersey: John Wiley and Sons, Inc. p. 259. ISBN 0471-44995-4. 597.177/dc22. {{cite book}}: |access-date= requires |url= (help)
  • Valeiras, J. (4 September 2006). "Atlantic Black Skipjack" (PDF). ICCAT Manual. ICCAT: 233–238. Retrieved 08 September 2010. {{cite journal}}: Check date values in: |accessdate= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  • Ursin, Michael (January) [1977], A Guide to Fishes of the Temperate Atlantic Coast, pp. 198–199 {{citation}}: Check date values in: |date= (help)
  • McClane's New Standard Fishing Encyclopedia and International Angling Guide, January [1965], p. 553 {{citation}}: Check date values in: |date= (help)
  • GoFISHn, 2011, retrieved 4 January 2011
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