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[Tuna
Ecology & Biology] -> [Tuna
Biology & Behaviour] -> [SEPoDyM]
Tuna Fisheries described in SEPoDyM
The 1999 Pacific tuna catch (2,380,271 mt) represented 67% of the provisional estimate of world tuna catch (3,571,114 mt). This global tuna catch is dominated by two tropical species, skipjack (Katsuwonus pelamis) and yellowfin (Thunnus albacares), which inhabit the surface mixed layer. Amongst the top predators of the tropical pelagic ecosystem, these two species have the greatest biomass and the largest forage requirement (Kitchell et al., 1999).
Total western central Pacific Ocean (WCPO) tuna catch by species
(skj; skipjack, yft; yellowfin, bet; bigeye, alb; albacore)
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Skipjack tuna fisheries
The skipjack population and fisheries are the first described in SEPODYM. Three different fishing gears are described: purse-seine, pole-and-line and a group of mixed domestic gears from the Philippines and Indonesia. A total of ten fleets are represented, each with separate catchability coefficients.
An age-based selectivity function is used for each gear. Fishing effort of each fleet vary by month and in space, with a one degree square resolution except for the Philippine and Indonesia fleets that provide data aggregated by five degree square, and year.
The catchability coefficients are scaled to obtain estimated catches at the
same level as observed catches. Results of the simulation are compared to
observed fishing data by fleets, such as total monthly catch, spatial
distribution of catch, and distribution of length frequencies.
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Examples
of comparisons between predicted and observed fishing data
Total monthly catch of Fiji pole and line fleet
Total monthly catch of Taiwan purse seine fleet
Monthly spatial correlation of U.S. purse seine fleet
Length frequency
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