TITLE:
Influence of Climatic Conditions on the Time Series Fluctuation of Yellowfin Tuna Thunnus albacares in the South Pacific Ocean
AUTHORS:
Ashneel Ajay Singh, Naoki Suzuki, Kazumi Sakuramoto
KEYWORDS:
Yellowfin Tuna, Global Mean Land and Ocean Temperature Index, Pacific Warm Pool Index, Southern Oscillation Index, Thunnus albacares
JOURNAL NAME:
Open Journal of Marine Science,
Vol.5 No.3,
June
3,
2015
ABSTRACT: Yellowfin tuna (Thunnus
albacares) is one of the most commercially important fish species for South
Pacific island nations and territories and for effective conservation efforts
it is important to understand the factors which affect its time series pattern.
Our research was aimed at elucidating the climatic factors which affected the
trajectory of the yellowfin tuna stock in the Eastern and Western South Pacific
Ocean. We utilized various climatic factors for the years t - n with n = 0, 1, ..., 8 and investigated their statistical
relationship with the catch per unit effort (CPUE) of yellowfin tuna stock from
1957-2008 for three South Pacific zones ranging from the East to the West Pacific
Ocean within the coverage area of the Western and Central Pacific Convention
Area. Results showed that the climatic conditions of: (i) the global mean land
and ocean temperature index (LOTI), (ii) the Pacific warm pool index (PWI) and
(iii) Southern Oscillation Index (SOI) had significant relationship with the
CPUE of yellowfin tuna in all three zones. LOTI, PWI and SOI were used as
independent variables and fitted through modeling to replicate the CPUE
trajectory of the yellowfin tuna in Zone 1, Zone 2 and Zone 3. Model selection
was based on significant parameter estimates (p R2 values. Models selected for all
three zones had LOTI, PWI and SOI as the independent variables. This study
shows that LOTI, PWI and SOI are climatic conditions which have significant
impact on the fluctuation pattern of the yellowfin tuna CPUE in the Eastern and
Western South Pacific Ocean. From the findings of this study it can be
recommended that when management decisions are made for yellowfin tuna fishery
conservation and sustainability in the Eastern and Western South Pacific, it is
imperative to take the effect of climatic factors into account.