Identifying the ecologically significant habitats of Yellow-fin tuna (Thunnus albacares, Bonnaterre, 1788) of Iranian purse seine fishery in the Gulf of Oman and Indian Ocean: An approach using satellite imagery and fishery data

Ecological fluctuations are influential factors affecting marine fish populations. The main primary objective of this study was to determine the catch probability of yellowfin tuna (Thunnus albacares, Bonnaterre, 1788) in the Indian Ocean and the Gulf of Oman, as well as its environmental preferences. This study employs generalized additive models (GAMs) to examine the spatiotemporal pattern of yellowfin tuna purse seiners, placing particular emphasis on the analysis of satellite imagery and environmental data. The results derived from the GAMs showed that the presence of yellowfin tuna was related to factors including sea surface height (SSH), salinity (SAL), latitude, and sea surface current velocities (velocity). Based on the findings of this research, it can be concluded that Iranian waters of the Gulf of Oman provide suitable habitats for yellowfin tuna during the autumn season, while in the Indian Ocean, these conditions are observed during the summer. Furthermore, the probability of successfully catching yellowfin tuna is higher in the Gulf of Oman than in the studied region of the Indian Ocean, with the catch probability predicted to be higher between 57°E and 69°E and for latitudes ranging from 5°N to 5°S and 20°−25°N. The study also found that areas with a sea surface temperature (SST) of 23–33 °C, SSH of 151–223 cm, and chlorophyll-a (Chl-a) concentration of 0.08–0.6 mg/m3 achieve higher catches than those with low SST, SSH, and Chl-a concentration. The model trained with data from all seasons was used to examine the seasonal variation in potential fishing grounds. Yellowfin tuna abundance varies seasonally and from year to year, depending on sea conditions and their behavior.