Yellowfin Tuna

Thunnus albacares

The Science

yellowfin_tuna
anglersjournal.com

Taxonomic description

  • Sleek torpedo-shaped body for fast movement. 
  • Coloration: dark blue on the back, changes from yellow to silver down to the belly.
  • Dorsal and anal fins are bright yellow giving the fish its name.
  • Difficult to distinguish from other tuna species except for the elongated, sickle-shaped dorsal and anal fins found on large adults [2]
  • Can grow to be 1.8 m (6 feet) long and over 180 kg (400 lbs) [1]

Distribution

  • Highly migratory fish and are found in warm seas all over the world except the Mediterranean [2]
  • Can travel across the entire ocean basin. [1]

Life history

  • Fast growing fish with a somewhat short life span of 6 to 7 years. [1]
  • Live 8 yrs, but most are mature enough to reproduce around age 2 or 3 [2].
  • Spawn at sea throughout the year in tropical waters, and in spring –summer in cooler waters. [1,2]
  • 24° C (75° F) is thought to be the lowest temperature limit for spawning. [2]
  • Can produce two to seven million eggs per spawn. [2]

Habitat

  • Travel in schools of similarly sized fish.
  • Mostly found in the surface layer (≤100 m or 330 ft) of the open ocean above the thermocline, but capable of diving over 1000 m (3300 ft) [1]
  • Typically found in water temperatures between 15° – 31° C (59° - 88° F). [3]
  • Known to make migratory trips to higher latitudes as the temperature of the water increases. [1] 
  • Gather in areas with high productivity where smaller prey is available.
  • Feed opportunistically in open ocean on small fish, squid and invertebrates such as pelagic crabs [2,3]
  • Predators include sharks, billfish and large marine mammals. 

The Fishery

Point Loma Sport fishing

Seasonal availability

  • Fishery open year-round, mostly recreational off San Diego in August & September

Managing authority

  • Managed federally under the Highly Migratory Species Fisheries Management Plan where NOAA & the Pacific Fishery Management Council establish permit & operational requirements, gear restrictions, & mandatory workshops for fishers [5].
  • As a member of the Inter-American Tropical Tuna Commission (IATTC), the U.S. has implemented purse seine fishery closure & catch retainment requirements to limit illegal discarding of undersized tuna [5]
  • International Dolphin Conservation Program sets guidelines to reduce bycatch of dolphins & undersized tuna [5]

Gear type

  • Mostly purse seines, but troll, hook-and-line, & pelagic longlines are also used. Hook and line is used recreationally.

Status of the fishery

  • NOAA defines population as “abundant” and fishing rate as “sustainable” [5]
  • Monterey Bay Aquarium’s “Fish Watch” lists hook-and-line tuna as “Best Choice” [6]
  • Most regulations focus on reducing the catch and mortality of non-target species.
  • U.S. fishermen responsibly harvest tuna by following strict international and domestic regulations aimed at reducing fishery impacts on other species (e.g., longliners use special hooks and bait that reduce bycatch; fishers train in the safe release of non-target species; vessels are regularly monitored by scientists & managers who reassess management actions as needed [5]

Potential ecosystem impacts

  • Species is fairly resistant to fishing pressure given early maturing, high fecundity, moderate life span, & wide distribution [7]
  • Troll & hook-and-line have relatively low bycatch [5] whereas purse seines and long lines potentially result in moderate to high bycatch of species associated with yellowfin schools if actions are not taken to reduce bycatch and mortality rates [5]
  • Purse seiners using fish aggregating devices (FADs, manmade floating objects) to attract yellowfin must take precautions to avoid bycatch of juvenile yellowfin & non-target pelagic species. 

The Seafood

Tuna Poke, norecipes.com

Edible portions

  • Usually sold as rounds, loins, or steaks  

Description of meat

  • Mild, meaty flavor; firm texture
  • The flesh has a deep red color when raw

Culinary uses

  • Eaten raw or cooked, but this fish loses its flavor & dries out when well-done [13].
  • May be frozen, but tightly wrap in plastic & keep it out of direct contact with ice or water to ensure a longer shelf-life 
  • Common preparations are to grill or sear the outside leaving the center rare [14]
  • Before cooking, season the steaks (this can be as simple as salt & pepper)
  • Searing is easy- heat oil in pan over medium-heat, then place & cook the seasoned steak to desired temperature
  • Common recipes include seared ahi, ahi burgers, ahi tacos, ahi salads, sesame crusted tuna, ahi tuna steak,

Nutritional information  

  • Raw (3 oz, 85 g) [9]

Toxicity report

  • No consumption advisories are listed for troll or pole-caught yellowfin as these methods catch younger tuna with lower mercury levels [11]
  • Potential for mercury accumulation in larger tuna only (caught by seine or longline). Recommended servings that can safely be eaten per month are 4 or more for adults, 3 for kids 6-12 yr old, 3 for kids 0-5 yr old [12]

Seasonal availability

  • Fresh in San Diego August–September [10]

References

1. FishWatch. 2013. Yellowfin Tuna. National Oceanic and Atmospheric Administration (NOAA) Fish Watch & Seafood Profiles. www.fishwatch.gov/seafood_profiles/species/tuna/species_pages/pacific_ye...

2. South Atlantic Fishery Management Council. 2013. Yellowfin Tuna. www.safmc.net/fishidandregs/fishgallery/yellowfintuna/tabid/257/default....

3. Froese, R., Pauly, D., eds. 2008."Thunnus albacares" in FishBase.  www.fishbase.org/summary/SpeciesSummary.php?genusname=Thunnus&speciesnam...

4. Horst, J. 2013. Yellowfin! Louisiana Fisheries. www.seagrantfish.lsu.edu/resources/factsheets/yellowfin.htm

5. FishWatch: 2013. Pacific Yellowfin Tuna. NOAA. www.fishwatch.gov/seafood_profiles/species/tuna/species_pages/pacific_ye....

6. Seafood Watch: 2013. Yellowfin Tuna. Monterey Bay Aquarium. www.montereybayaquarium.org/cr/seafoodwatch/web/sfw_factsheet.aspx?fid=219.

7. Roberts, S. 2010. Seafood Watch Yellowfin Tuna Report. Monterey Bay Aquarium. Monterey Bay Aquarium. www.montereybayaquarium.org/cr/cr_seafoodwatch/content/media/mba_seafood....

8. "Highly Migratory Species: Background." Pacific Fishery Management Council. Pacific Fishery Management Council, 20 Nov. 2012. Web. 10 Aug. 2013. www.pcouncil.org/highly-migratory-species/background/

9. SELF Nutrition Data: Know What You Eat. 2013. Fish, tuna, fresh, yellowfin, raw.. http://nutritiondata.self.com/facts/finfish-and-shellfish-products/4150/2.

10. California Dept. of Fish & Wildlife. 2013. Marine Sportfish Identification: Tunas & Mackerels.. www.dfg.ca.gov/marine/mspcont1.asp.

11. Monterey Bay Aquarium. 2013. “Yellowfin tuna.” Seafood Watch. www.montereybayaquarium.org//cr/SeafoodWatch/web/sfw_factsheet.aspx?fid=...

12. EDF Seafood Selector. 2013. Tuna. Environmental Defense Fund. http://seafood.edf.org/tuna.

13. Riches, D.. 2013. Grilling Tuna: Rare or well you need to know the best method for grilling tuna. About.com. http://bbq.about.com/od/fishandseafood/a/aa103004a.htm

14.  Bauer, E.. 2006. Seared Ahi Tuna. Simply Recipes. http://www.simplyrecipes.com/recipes/seared_ahi_tuna/