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Exploring the beautiful nature of California
Marine Fish: Yellowfin
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Fishes are aquatic vertebrates that have fins, gills and
scales. Gills are the part of the respiratory system that
provide surface area for exchanging oxygen and carbon dioxide
under water.
Fish are ectotherms, commonly referred to as
'cold-blooded', meaning their temperature is regulated by the
temperature of their environment. They have a range of diets,
being herbivores, carnivores, or omnivores. Some fish reproduce
by laying eggs, while others reproduce by bearing live young.
California fish species reside in freshwater and coastal/marine
waters. Coastal, or marine fish are an abundant and valuable
resource. However, the ocean's supply is not limitless, and
therefore careful planning and education must be undertaken to
ensure the sustainability of the world's largest food source.
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Yellowfin tuna are found throughout the tropical Pacific. The
world's single largest biomass of yellowfin inhabits the Eastern
Tropical Pacific Ocean (ETP), ranging from Chile to southern
California. Tagging studies indicate that the ETP stock is a
single population, with seasonal coastal migrations but no
large-scale movement to the central or western Pacific.
In the
daytime, mature yellowfin associate with dolphins to some degree
in all the world oceans. However, the relationship with dolphins
is well-developed in the eastern Pacific.
The yellowfin tuna is one of the largest tuna species, reaching weights of over 300 pounds, but is significantly smaller than the Atlantic and Pacific bluefin tunas that can reach over 1,000 pounds and slightly smaller than the bigeye tuna and the southern bluefin tuna.
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On November 30, 2010, Mike Livingston, of Sunland, California
reeled in a 405.2 pound Yellowfin off the tip of the Baja peninsula aboard the vessel, the Vagabond. Livingston's 86 inch catch, which had a girth of 61 inches, is still pending verification by the International Game Fish Association to replace Wiesenhutters 388 pounder as the new all-tackle World Record holder.
Although mainly found in deep offshore waters, yellowfin tuna may approach shore when suitable conditions exist. Mid-ocean islands such as the Hawaiian archipelago, other island groups in the Western Pacific, Caribbean and Maldives islands Indian Ocean, as well as the volcanic islands of the Atlantic such as Ascension Island often harbor yellowfin feeding on the baitfish these spots concentrate close to the shoreline. Yellowfin may venture well inshore of the continental shelf when water temperature and clarity are suitable and food is abundant. |
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Yellowfin tuna prey include other fish, pelagic crustaceans, and squid. Like all tunas their body shape is evolved for speed, enabling them to pursue and capture fast-moving baitfish such as flying fish, saury and mackerel. Schooling species such as myctophids or lanternfish and similar pelagic driftfish, anchovies and sardines are frequently taken. Large yellowfin prey on smaller members of the tuna family such as frigate mackerel and skipjack tuna.
In turn, yellowfin are preyed upon when young by other pelagic hunters, including larger tuna, seabirds and predatory fishes such as wahoo, shark and billfish. As they increase in size and speed, yellowfin become able to escape most of their predators. Adults are threatened only by the largest and fastest hunters, such as toothed whales, particularly the false killer whale, pelagic sharks such as the mako and great white, and large blue marlin and black marlin. The main source of mortality, however, is industrial tuna fisheries. |
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