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 https://datingranking.net/es/citas-filipino/ 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) is good pelagic, highest returns species which have a max age lower than cuatro.five years (Fromentin Fonteneau, 2001). Just like the an important commercial species, it is mostly caught when you look at the warm and you may subtropical oceans of the Pacific, Atlantic, and Indian waters. Catches off skipjack tuna are more than 70% of all the tuna grabs on the western and you can main Pacific Water (WCPO), in which 1 / 2 of the new world’s tuna try stuck (Food and Farming Team of your United nations, 2011). On the WCPO, 86% off skipjack tuna was c). During fishery products, some elementary physiological variables (e.g., size, weight) are necessary having researching fishery durability also to assess stocks (Fromentin Fonteneau, 2001; Hampton, 2000).
Weight–size dating and you can Fulton’s reputation items out of skipjack tuna (Katsuwonus pelamis) about west and you may central Pacific Sea
The weight–duration relationship (WLR) and you can Fulton’s status grounds (K) are a couple of head parameters included in fishery search, and have now become directly relevant since they was indeed very first advised (Froese, 2006). The latest WRL is the relationship ranging from lbs and you can length to possess an excellent considering variety, and will be used to imagine the development development. Prior studies have noticed this new WLRs out of skipjack tuna in the CPWO (Wild Hampton, 1993; Sunrays Yeh, 2002; Sunrays ainsi que al., 2003; Froese Pauly, 2014); although not, it mainly centered on the brand new WLR of the many skipjack tuna specimens stuck. Hence, the information protected by other ages/looks categories was not obviously recognized. More over, according to a recently available WCPO skipjack tuna standing report (Harley mais aussi al., 2011), small fish (40–60 cm; 1–2 yrs) ruled grabs, except when you look at the 2005. Yet not, nothing is now identified concerning differences between physiological details during the other growth stages. Distress eters of the WLR) were used to compare the distinctions among the many more values of a single observance, and various in the situ observations; specifically, because the an amount may affect b opinions, and higher b philosophy is actually on the faster an amounts (Froese, 2006). The worth of K is actually calculated throughout the weight and you can length, and certainly will be employed to imagine alterations in nutritional reputation. Couple knowledge nowadays possess tested brand new K worthy of getting skipjack tuna. Early in the day research has shown that K values to other seafood change seasonally (pick Froese, 2006 and you may sources therein) along with increases phase. Skipjack tuna are known to become firmly influenced by macro-marine conditions, e.g., Este Nino and you will La Nina (Lehodey ainsi que al., 1997; Lehodey mais aussi al., 2013; Loukos ainsi que al., 2003); although not, the same changes such as almost every other seafood kinds just weren’t reported to own skipjack tuna. Even in the event both the WLR and you will K is also reflect the development criteria from particular fish, zero education one to combine investigation of the two indicator have been stated. Ergo, they stays unclear if they has actually uniform trend you to mirror the brand new people services of skipjack tuna about WCPO.