The annual fishery of the Indian Oil Sardine (IOS), Sardinella longiceps, seems to be influenced by the ambient conditions prevailing in the habitats during their early life-history. The present study is aimed at understanding the putative behaviour of IOS along the southwest coast of India (SWCI) to monsoonal upwelling which triggers surface productivity. Mixed layer temperature is observed to be an indicator of the habitat choice and reproductive performance of IOS. A Multi-Criteria Analysis (MCA) model was envisioned to explain the interannual variability of the IOS fishery. In this model, the coactions of variables such as standardized catch per unit effort (SCPUE) of IOS in the first quarter (January to March), southwest monsoonal upwelling index (SWM-UI), and pre-monsoonal mixed layer temperature (PM-MLT) over three decades from 1985 to 2016 were looked upon as indicators to explain the interannual fluctuations in the fishery. Eight different criteria for eight ranks were assigned using reference values for variables. The model ranks the years based on the respective conditions defined based on the suitability criteria for IOS. The model showed a strong relationship of the variables on the annual IOS fishery and revealed that the higher first quarter SCPUE ($>3.678$) and SWM-UI ($>758.7$ kg/m/s) influences the interannual variability of the fishery significantly. The primary causative factor for the collapse of this fishery during 1992-99 was the frequent occurrence or co-occurrence of extreme climatic events such as El Niño, La Niña and Indian Ocean Dipole (IOD). Further, a significant increase ($p<0.05$) in IOS fishery was observed during 2000-07 due to favourable upwelling conditions along the SWCI. The uncertainties prevailing in a complex tropical ecosystem and associated challenges in resolving a multi-craft-gear fishery were addressed using statistical tools to infer logical explanation on the decline and revival of IOS.

印度油沙丁鱼 (IOS)、长头沙丁鱼、似乎受到栖息地在其早期生活史中普遍存在的环境条件的影响。本研究旨在了解印度西南海岸 (SWCI) 沿线的 IOS 对触发地表生产力的季风上升流的假定行为。观察到混合层温度是 IOS 栖息地选择和繁殖性能的指标。设想了一个多标准分析（MCA）模型来解释 IOS 渔业的年际变化。在该模型中，IOS在第一季度（1-3月）的单位努力标准化捕捞量（SCPUE）、西南季风上升流指数（SWM-UI）、1985 年至 2016 年 30 年间的季风混合层温度 (PM-MLT) 被视为解释渔业年际波动的指标。使用变量的参考值为八个等级分配了八个不同的标准。该模型根据基于 IOS 的适用性标准定义的相应条件对年份进行排名。该模型显示了年度 IOS 渔业的变量之间的强相关性，并显示较高的第一季度 SCPUE ($>3.678$) 和 SWM-UI ($>758.7$kg/m/s) 显着影响渔业的年际变化。该渔业在 1992-99 年期间崩溃的主要原因是极端气候事件的频繁发生或同时发生，例如厄尔尼诺、拉尼娜和印度洋偶极子 (IOD)。此外，显着增加（$磷<0.05$) 由于 SWCI 沿线有利的上升流条件，在 2000-07 年期间观察到 IOS 渔业。复杂的热带生态系统中普遍存在的不确定性以及解决多渔具渔业的相关挑战通过使用统计工具来推断 IOS 衰退和复苏的逻辑解释得到解决。