Satellite chlorophyll concentration as an aid to understanding the dynamics of Indian oil sardine in the southeastern Arabian Sea

Menon, NN; Sankar, S; Smitha, A; George, G; Shalin, S; Sathyendranath, S; Platt, T. 2019 Satellite chlorophyll concentration as an aid to understanding the dynamics of Indian oil sardine in the southeastern Arabian Sea. Marine Ecology Progress Series, View. 1-11. https://doi.org/10.3354/meps12806

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Official URL: https://doi.org/10.3354/meps12806

Abstract/Summary

Coastal waters of Kerala, which form an integral part of the Malabar upwelling zone off the southwest coast of India, constitute an important fishing region for small pelagics. Satellite remote sensing data from 1998-2014 were used to test the hypothesis that fluctuations in the landings of Sardinella longiceps, the major pelagic fish landed in the area designated as the South Eastern Arabian Sea (SEAS), are influenced by seasonal variability in phytoplankton biomass (measured as chlorophyll a [chl a] concentration), under the changing strength of physical parameters such as sea surface temperature (SST), alongshore wind stress, Ekman mass transport, sea level anomaly (SLA) and Kerala rainfall. Multiple linear regression analysis (MLRA) was used to assess the influence of physical forcing mechanisms on chl a concentration on monthly and seasonal scales. We found that SLA, alongshore wind stress, SST and rainfall were ranked 1 to 4, respectively, and the first 3 factors significantly influenced the chl a concentration of SEAS. Pearson’s correlation analysis between monthly chl a and sardine landing (with chl a leading) showed a maximum positive correlation (+0.26) at 2 and 3 mo lags, emphasizing that the influence of chl a on the fishery of S. longiceps is seasonal (r = 0.35 for seasonal lead-lag correlation) in the coastal waters of SEAS. Variation in phytoplankton biomass, as evidenced by chl a fluctuations, seems to have a decisive role in regulating the physiological condition of larvae spawned during the southwest monsoon season, their juveniles and finally the adults that are recruited into the fishery in the next season. Using the quantity of phytoplankton as a predictive tool will exploit the presumptive trophic link to aid understanding of sardine fishery dynamics in upwelling zones.

Item Type: Publication - Article
Divisions: Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User: Kim Hockley
Date made live: 13 Feb 2019 14:16
Last Modified: 25 Apr 2020 09:59
URI: http://plymsea.ac.uk/id/eprint/8112

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