ROLE OF SUB SURFACE TEMPERATURE, SALINITY AND CHLOROPHYLL TO ALBACORE TUNA ABUNDANCE IN INDIAN OCEAN
Abstract: The swimming layer
is one of the important factors to get maximum catches, especially on tuna
longline effort. The vertical abundance of the albacore tuna was investigated
based on catch data and 3-DINDESO Ocean Model data, such as sub-surface
conditions of sea water potential temperature (Temp), salinity (Sal) and mass
concentration of diatoms and flagellates expressed as chlorophyll (Chl) in the
Eastern Indian Ocean period 2014-2015. Combining he statistical method of
generalized additive model (GAM) was performed to analysis in this study. There
were seven GAM models that generated with the number of ALB vertical abundance
as a response variable, and Temp, Sal, and Chl as predictor variables. Sal has
highly significant (P < 0.001) while Chl and Temp significant (P < 0.01)
to ALB vertical abundance. Deduced from GAMs, indicated that a negative effect
of Sal on the number of ALB was observed at salinity >34.52 psu. There was a
positive effect of salinity on the number of ALB, which was from 34.30 to 34.47
psu and Chl showed a positive effect of this variable on the number of ALB
caught occurred between 0.01 mg/m3 and 0.12 mg/m3 in the region of high
confidence level where negative effect on > 0.13 mg/m3. While ALB catches
abundance varied in the temperature range with the highest frequency at
24.0-24.9 °C. Sal was the most important environmental variable to the number
of ALB vertically caught, followed by Chl and Temp.
Keywords: Albacore tuna;
abundance; subsurface; temperature; salinity; chlorophyll; Indian Ocean
Penulis: Dian Novianto, Eko
Susilo
Journal Code: jpperikanangg160044
