Where does the tuna in your sandwich come from?
That can over there.
Is that where it lives?
Mmmm it seems a little small.
How does the tuna get into the can?
I don’t know but probably angry.
What you know may not be what’s important.
If you have only seen something in a little can it may be difficult to envision it as a top level, hard hitting ocean predator. Tuna is more than what you see in the can.
Dressed like a rock star
Albacore Tuna are handsome fish with torpedo-shaped bodies, smooth skin, and long, streamlined fins. The pectoral fins may be at least half the length of their bodies. Their metallic, dark blue back and silvery white sides make them nearly invisible in the water.
They can grow up to nearly four feet in length and weigh almost 80 pounds. In our waters they average 20- to 30-inches and up to about 35 pounds. These fish belong to the North Pacific stock and are generally juvenile or sub-adult fish that have not spawned.
Eats like an athlete
Albacore can swim over 50 miles per hour which facilitates long annual migrations and successful predation. They have a high metabolism and thus may consume as much as 25 percent of their own weight every day.
Albacore tuna are unique among the tunas because their primary food sources are octopus and squid, versus fish. As a top ocean carnivore, they prey on schooling stocks such as squid, sardines, anchovy, crabs, lobsters, shrimp.
Albacore predators include larger species of billfish, tuna, sharks, and humans.
Hunting and Hunters
This fish has a highly evolved circulatory system that regulates body temperature, increases muscle efficiencies, supports high metabolism, and high blood pressure, volume and hemoglobin.
All of this helps tuna increase their ability to absorb oxygen. They lack structures needed to pump oxygen rich water over their gills. To compensate they must constantly swim and keep their mouths open to breathe.
Going to School
Similarly-sized Albacore swim together in a school. Each school is very large and can be up to 19 miles wide. Migrating Albacore may cover over 50 miles each day when migrating. Migration timing and distance vary based on oceanic conditions.
There are six distinct Albacore stocks that generally do not mix (North Pacific has two groups one that heads for Baja California and the other for the coasts of Oregon and Washington). Other stocks include Atlantic and Indian oceans, and the Mediterranean Sea.
Migrations
North Pacific 2- to 4-year old Juveniles begin in spring and early summer from waters near Japan. They spawn between March and July. Females broadcast eggs near the surface for fertilization. They may release between 800,000 and 2.6 million eggs every time they spawn.
By July, they move into inshore waters 15-200 miles off the U.S. Pacific coast and hang out through September. They spend fall and winter in the western Pacific Ocean.
Management of
The migration across several international boundaries complicate specie management along with its economic importance. The gross national product of several countries depends on the tuna.
In the U.S., the National Oceanic Atmospheric Administration (NOAA) Fisheries have been tagging and studying the fish and recommending management actions to avoid overfishing. Several stocks are in significant decline and the species’ overall population trend is decreasing. Albacore are considered to be ‘Near Threatened.’
Bait and Switch
Albacore demand is sometimes fraudulently met through substitution. Escolar (Lepidocybium flavobrunneum) has been frequently substituted, or ‘confused,’ with Albacore.
Escolar are known to create potential health problems when consumed. While it is not toxic per se it has caused enough concern for several countries to ban it.
REFERENCES:
–Oregon Dept. of Fish and Wildlife (https://myodfw.com/fishing/species/albacore-tuna, commercial landing statistics, and 2018 Albacore Annual Reports)
–NOAA Fisheries (https://www.fisheries.noaa.gov/species/pacific-albacore-tuna)
–Wikipedia Albacore (https://en.wikipedia.org/wiki/Albacore)
–The Atlantic, 59% of the tuna Americans eat is not tuna (https://www.theatlantic.com/business/archive/2013/02/59-of-the-tuna-americans-eat-is-not-tuna/273410/