Weight–length relationship and you may Fulton’s standing things out of skipjack tuna (Katsuwonus pelamis) throughout the west and you may main Pacific Ocean

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.

Introduction

Skipjack tuna (Katsuwonus pelamis) is good pelagic, large output species that have an optimum years below cuatro.five years (Fromentin Fonteneau, 2001). Since the a significant industrial kinds, it’s generally caught from inside the tropical and subtropical oceans of the Pacific, Atlantic, and you will Indian oceans. Captures of skipjack tuna are more 70% of all tuna captures regarding the west and you will central Pacific Ocean (WCPO), where half of the fresh world’s tuna is trapped (As well as Farming Business of one’s United nations, 2011). From the WCPO, 86% away from skipjack tuna try c). During the fishery items, some elementary biological parameters (e.g., size, weight) are crucial for researching fishery sustainability and to assess brings (Fromentin Fonteneau, 2001; Hampton, 2000).

Weight–duration relationship and Fulton’s condition situations away from skipjack tuna (Katsuwonus pelamis) about western and you may central Pacific Ocean

The weight–size matchmaking (WLR) and you will Fulton’s reputation basis (K) are two main variables found in fishery look, and also http://datingranking.net/es/aplicaciones-de-citas/ have already been closely related since they was first advised (Froese, 2006). New WRL is the relationship anywhere between lbs and you can duration getting good given species, and will be used to imagine the development development. Previous research has sensed this new WLRs away from skipjack tuna from the CPWO (Wild Hampton, 1993; Sunrays Yeh, 2002; Sunrays et al., 2003; Froese Pauly, 2014); but not, they primarily dedicated to the fresh new WLR of all skipjack tuna specimens trapped. Hence, everything included in different ages/system categories wasn’t obviously recognized. Furthermore, according to a current WCPO skipjack tuna status statement (Harley et al., 2011), brief seafood (40–sixty cm; 1–۲ years) ruled catches, except into the 2005. However, nothing is understood concerning differences when considering physiological details while in the some other development levels. Distress eters of your WLR) were used to compare the differences one of several additional level of just one observance, as well as other in the situ findings; particularly, once the a values may affect b opinions, and higher b viewpoints was with the shorter a stages (Froese, 2006). The worth of K is actually computed regarding the pounds and you may size, and will be employed to imagine alterations in nutritional position. Few studies in recent years has actually tested the brand new K worth getting skipjack tuna. Past research has shown that the K opinions with other seafood changes seasonally (discover Froese, 2006 and you will sources therein) along with growth phase. Skipjack tuna are known to feel highly affected by macro-aquatic criteria, age.g., Este Nino and Los angeles Nina (Lehodey ainsi que al., 1997; Lehodey mais aussi al., 2013; Loukos mais aussi al., 2003); not, a similar changes as with other seafood types weren’t claimed to own skipjack tuna. In the event the WLR and you may K can mirror the growth requirements out of specific seafood, zero studies one to blend research of the two indices have been said. Therefore, it remains undecided whether they has uniform style you to mirror the brand new society services regarding skipjack tuna on the WCPO.