This paper describes the weight–length relationships (WLRs) and Fulton’s condition factors (K) of skipjack tuna (Katsuwonus pelamis) in purse seine fisheries from three cruises in the western and central Pacific Ocean (WCPO): (ND12), and (JJ13). The fork length and weight of a total of 1678 specimens were measured. The results showed that the fork length of more than 70% of specimens was below 60 cm (76% in AS09, 87% in ND12, and 73% in JJ13). The coefficient b in the combined sex group was 3.367, 3.300 and 3.234 in JJ13, AS09 and ND12, respectively. The b values of WLRs when fork length was >60 cm were significantly less than 3 (P = 0.062), but when fork length was <60 cm they were significantly greater than 3 (P = 0.028). The K value ranges of JJ13, AS09 and ND12 in different fork length groups were 1.3–1.84 (1.62 ± 0.18), 1.57–2.02 (1.86 ± 0.15), and 1.44–1.78 (0.65 ± 0.13), respectively. Moreover, K values in different fork length classes for each cruise had one turning point: 60–65 cm for JJ13; 60–65 cm for ND12; and 55–60 cm for AS09. The results of this study provide basic information on the WLRs and K values of skipjack tuna in different seasons and growth phases in the WCPO, which are useful for fishery biologists and fishery managers.
Skipjack tuna (Katsuwonus pelamis) try an effective pelagic, large productivity varieties having a maximum years lower than cuatro.5 years (Fromentin Fonteneau, 2001). Just like the an essential industrial kinds, it’s mainly trapped in the exotic and you can subtropical waters of Pacific, Atlantic, and Indian oceans. Catches away from skipjack tuna had been more than 70% of all the tuna catches throughout the western and you will main Pacific Water (WCPO), in which 1 / 2 of the brand new world’s tuna try stuck (Food and Farming Team of the Us, 2011). Regarding WCPO, 86% from skipjack tuna was c). Through the fishery points, some elementary biological details (e.grams., dimensions, weight) are essential for researching fishery durability and determine holds (Fromentin Fonteneau, 2001; Hampton, 2000).
Weight–length matchmaking and you may Fulton’s standing activities of skipjack tuna (Katsuwonus pelamis) from the western and main Pacific Ocean
The extra weight–length dating (WLR) and you will Fulton’s position grounds (K) are two main details included in fishery lookup, and just have already been directly related because they have been basic recommended (Froese, 2006). The WRL ‘s the relationship between lbs and you will length getting a great provided species, and can be employed to guess the organization trend. Past studies have noticed the new WLRs out-of skipjack tuna on CPWO (Crazy Hampton, 1993; Sun Yeh, 2002; Sunlight ainsi que al., 2003; Froese Pauly, 2014); but not, it mainly concentrated on the newest WLR of the many skipjack tuna specimens trapped. Thus, all the information protected by some other ages/human body kinds was not demonstrably understood. More over, centered on a current WCPO skipjack tuna standing report (Harley mais aussi al., 2011), brief fish (40–sixty cm; 1–24 months) reigned over grabs, except inside the 2005. Although not, nothing is now recognized concerning the differences when considering physiological parameters throughout the different increases stages. Frustration eters of WLR) were used to compare the distinctions one of the other level of one observation, and differing when you look at the situ observations; particularly, as a grade make a difference b beliefs, and better b values was regarding the shorter a grade (Froese, 2006). The value of K try computed on the weight and duration, and can be employed to imagine alterations in health condition. Partners studies lately features checked brand new K worth for skipjack tuna. Earlier in the day research has shown that K beliefs for other seafood alter seasonally (get a hold of Froese, 2006 and references therein) sufficient reason for gains phase. Skipjack tuna are recognized to end up being firmly influenced by macro-marine requirements, age.g., Este Nino and you will Los angeles Nina (Lehodey et al., 1997; Lehodey et al., 2013; Loukos et al., 2003); but not, an identical changes such as other seafood varieties were not said to have skipjack tuna. No matter if the WLR and you can K is mirror the development standards from certain seafood, no degree you to definitely merge research of these two indices was in fact reported. Ergo, they remains unclear whether or not they provides consistent styles one mirror new population features out-of skipjack tuna from the WCPO.