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BiologyThe albacore tuna forms schools, which can be up to an astonishing 30 kilometres wide (3). These enormous schools are sometimes associated with floating objects, such as sargassum weeds, and they may also form mixed schools with other tuna species, such as skipjack, yellowfin and bluefin tuna (2). In these schools, the albacore tuna undertakes great migrations in search of the best feeding and spawning grounds, strongly influenced by large oceanic phenomena such as El Niño (5) (6). Albacore tuna are able to reach impressive speeds, of up to 80 kilometres per hour, due to their highly evolved circulatory system that reduces the loss of heat generated by increased muscular activity. This allows them to maintain their body temperature at a higher level than the surrounding water, keeping their muscles warm and working efficiently (3). Unlike many fish, albacore tuna are not able to pump water over their gills to obtain oxygen from the surrounding water, and therefore need to swim constantly with their mouth open, to force water over their gills. A high volume and pressure of blood, and great haemoglobin concentration, all increases the ability of the fish to absorb the essential oxygen (3). Albacore tuna are believed to be pelagic spawners, meaning that the female releases her eggs, and the male his sperm, into open water, often near the water's surface (3). A female albacore tuna is capable of producing two to three million eggs per spawning season, which are released in at least two batches (2); however, the majority of these eggs will not survive to be adults (3). The tiny eggs are just one millimetre in diameter and are enclosed in an oil droplet to enable them to remain buoyant in the ocean. The eggs are fertilized by the male, and the resulting fertilized eggs develop rapidly, with hatching occurring in less than 48 hours (3). The large albacore tuna is one of the top carnivores within the ocean regions it inhabits, and it preys voraciously upon smaller schooling fish such as sardines and anchovy, and squid, consuming around 25 percent of its weight every day. The albacore tuna itself becomes prey for larger species of tuna, billfish and sharks (3).