Preliminary assessment, restoration and aquaculture support for a small wetland

In line with the strategy of regional wetland datasets integration to a common national digital platform, map of small wetlands less than 2.2 ha in Kochi Taluk was prepared. A representative small wetland at Edakochi village of Kerala was selected through maps and field visits for preliminary assessment and restoration. Shuttle Radar Topography Mission’s Digital Elevation Model (DEM) was used to assess the general elevation, slope and flow accumulation pattern of the selected wetland along with assessment of the catchment area and drainage pattern. Restoration works of the selected wetland was carried out vis-a-vis side bund strengthening and sluice gate fortification. The comparative analysis of water quality assessment of wetland before and after restoration revealed improvement in water quality parameters as well as increase in water level. The Dissolved Oxygen level of the aquatic system was found to have increased substantially along with other several favourable changes in water parameters due to the restoration activities. The restored wetland at Edakochi was further utilised for multispecies farming of prawns, Pearl spot, Milk fish and Grey mullet and the harvest indicated sustainable yield. Aquaculture practice in wetlands with real time scientific advisories could ensure continuous data generation and village level climate resilience

Climate change drivers influencing Indian mackerel fishery in south-eastern Arabian Sea off Kerala, India

The Indian mackerel Rastrelligerkanagurta(Cuvier, 1816) is one of the most important marine fishery resources along the south-eastern Arabian Sea along the coast of Kerala, south India. The effect of selected environmental variables on the Relative effort (Effort) and weighted catch per unit effort (cpue)of the fish were investigated using simple correlation and Path analysis. Six major oceanographic variables, namely sea surface temperature (SST), sea surface chlorophyll-a concentration (SSC), sea surface salinity (SSS), Precipitation (Pr) Indian Ocean Dipole (IOD) and Southern Oscillation Index (SOI) (ENSO index) were selected for the present study. Among these SST had the highest direct negative effect (-0.282, p SSC >SSS

Impact of climate change on the fishery of Indian mackerel (Rastrelliger kanagurta) along the Kerala coast off the southeastern Arabian Sea

Climate change impact varies at regional as well as species level and accordingly research needs to be focused on exploring the region-wise influence of oceanographic variations on key marine species. The present study depicts the annual and decadal fluctuations in Indian mackerel fishery along Kerala coast of southeastern Arabian Sea over a time period of 31 years (1985–2016), its relationship between four major oceanographic variables (SST, Pr, SSS and SSC) and future predictions under two Representative Concentration Pathways (RCPs). Coast specific changes of these oceanographic variables since 1960 provide a baseline status of the existing climatic conditions of the marine ecosystem of the SEAS whereas, the RCP projections till 2100 provide an insight to the future conditions. Generalized Additive Models (GAMs) has been used to comprehend the relation among the Weighted CPUE (cpue) and Relative effort (Effort) of Indian mackerel and the four major oceanographic variables. The GAM model could explain 68.9 % and 71.1 % deviance of cpue and Effort respectively. The significance of the most influential oceanographic variables on the cpue of Indian mackerel were in the order SST > Pr > SSC > SSS and for Effort were in the order Pr > SST > SSS > SSC. The projected cpue and Effort of Indian mackerel exhibits varying trends under the RCP 4.5 and RCP 6.0 scenarios. The future catch potential of Indian mackerel predicted under both RCP scenarios for the period 2020–2100 also show reduction, with the latter exhibiting a more drastic reduction. The study implies that for sustainable long-term fishery and to reduce the impact of climate change on Indian mackerel, the fishing pressure has to be maintained at low and healthy level