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.

Inclusion

Skipjack tuna (Katsuwonus pelamis) try a pelagic, large output types that have a maximum many years below 4.5 years (Fromentin Fonteneau, 2001). As the a significant industrial types, it’s mostly stuck during the exotic and you may subtropical oceans of your own Pacific, Atlantic, and you may Indian waters. Captures from skipjack tuna had been more than 70% of all the tuna captures on western and you will central https://datingranking.net/it/app-di-incontri/ Pacific Water (WCPO), in which half of the latest planet’s tuna try caught (As well as Agricultural Organization of your own United nations, 2011). Throughout the WCPO, 86% off skipjack tuna was c). During the fishery affairs, some basic physiological details (age.grams., size, weight) are essential having comparing fishery durability and determine stocks (Fromentin Fonteneau, 2001; Hampton, 2000).

Weight–length dating and you will Fulton’s condition products from skipjack tuna (Katsuwonus pelamis) from the western and central Pacific Ocean

The extra weight–length dating (WLR) and you may Fulton’s reputation foundation (K) are a couple of head parameters used in fishery lookup, and then have started closely related since they had been basic recommended (Froese, 2006). New WRL is the matchmaking between pounds and you will size for a good offered kinds, and will be used to imagine the growth development. Past research has thought the brand new WLRs off skipjack tuna about CPWO (Crazy Hampton, 1993; Sunshine Yeh, 2002; Sunrays ainsi que al., 2003; Froese Pauly, 2014); yet not, they mainly centered on the latest WLR of all of the skipjack tuna specimens trapped. Thus, every piece of information included in more ages/muscles categories was not obviously understood. More over, considering a recently available WCPO skipjack tuna status report (Harley et al., 2011), quick fish (40–sixty cm; 1–couple of years) ruled captures, but into the 2005. Yet not, little happens to be understood in regards to the differences between physical parameters through the additional gains levels. Misunderstandings eters of your own WLR) were used to compare the difference one of several some other degrees of one observation, and differing from inside the situ findings; particularly, as a levels make a difference to b opinions, and higher b opinions are regarding the quicker a values (Froese, 2006). The value of K is actually determined on the pounds and length, and certainly will be used to estimate alterations in health reputation. Few education recently have tested this new K value to have skipjack tuna. Prior research has shown that K thinking to many other fish transform seasonally (find Froese, 2006 and you can sources therein) along with development phase. Skipjack tuna are recognized to be highly impacted by macro-aquatic requirements, e.g., El Nino and you will Los angeles Nina (Lehodey ainsi que al., 1997; Lehodey mais aussi al., 2013; Loukos mais aussi al., 2003); yet not, an equivalent alter as in almost every other fish kinds weren’t claimed having skipjack tuna. Even in the event the WLR and you will K can also be echo the development standards out of particular fish, zero studies you to definitely mix studies of the two indices was indeed advertised. Ergo, they remains not sure if they has uniform styles one to mirror brand new populace qualities out of skipjack tuna in the WCPO.