South West India

Summary

The state of Kerala, located at the extreme southern narrow strip of the Indian sub-continent is wedged between the Arabian Sea to the west and the Western Ghats to the east. It is lying between 8°18', 12° 48' North latitudes and 74° 52', 77° 22' East longitudes. Kerala’s coastline of 590 km with 187 landing centres spreading over nine coastal districts and the Exclusive Economic Zone (EEZ) extends up to 200 nautical miles far beyond the continental shelf, which covers an area of 218,536 Sq km provide opportunities in traditional fishing in inshore waters from ages.

The hotspot area of south west India comprises of four coastal districts (South Zone: Thiruvananthapuram & Kollam and Central zone: Ernakulam and Alapuzha), and the rationale behind the section of this particular location is i) It falls within the upwelling ecosystem of the south-west coast of India,ii) this region has rich diversity and supports substantial marine and estuarine fisheries iii) identified as major spawning gyre of many pelagic species based on fish and larval surveys iv) has extensive system of backwaters.

Oceanographical context

The Indian subcontinent divides the northern Indian Ocean into two basins - the Arabian Sea and Bay of Bengal. The Arabian Sea is known for the intense annually reversing monsoon winds and high evaporation. Even though the Ekman transport is less during northeast monsoon than during southwest monsoon, especially south of 10°N, the heat transport south of the Arabian Sea keeps similar amplitude as that of south-west monsoon. Among the western boundary currents Somali Current of Arabian Sea is unique due to its strength and the reversal during monsoon season. The studies indicate a presence of two-gyre circulation system in the western Arabian Sea during south west monsoon. Another notable feature is the upwelling of cool subsurface waters in the Arabian Sea during the summer monsoon. 

Economic and social context

The marine fishery in Kerala state is characterized by multi-species, multi-fleet and largely open access system. The economy of Kerala relies heavily on fishing for subsistence, livelihood and employment. Within Kerala, consumption of fish is four times the national average. Furthermore, the state produces 16.6% of the shares of India’s total marine exports, the second largest in the country.

Kerala fisherfolk are found in all three major religious communities (Roman Catholic,Hindu, Muslim). There are clear distinctions among fisher folk based on caste and place differences in establishment of fishing rights, kind of craft and gear they use and their participation in community institutions and local governance. The density of population in Kerala coastline is very high when compared to its midlands and the highlands. There are 12 active fishermen per square kilometer of coastal seas in the state, as compared to that at the national level. Even with the importance of fishing industry in Indian economy, traditional fishing communities are lagging behind of many other communities in terms of socio-economic development.

Important fisheries

The striking feature of the marine fisheries of the Malabar upwelling area (Kerala) is the predominance of pelagic resources dominated by oil sardine (Sardinella longiceps) and Indian mackerel (Rastrelliger kanagurta), which support the western Indian Ocean’s largest coastal pelagic fishery. Kerala coast have major fisheries of the elasmobranches, cat fish, shrimps, cuttle fish, sardines, anchovilla, saurida & saurus, perches, sciaenids, mackerels, ribbon fish, seer fish, tunnis, prawn, anchovies, soles, sharks, rays, etc. Kerala ranks first in marine fish production of India forming nearly 25 per cent (average 5.75 lakh tonnes) of the total annual production. Currently the annual export of marine products from the state yields to the nation a foreign exchange of Rs. 1,100 crores.

Biodiversity of the region

Tropical marine ecosystem of Kerala coast includes lagoons, mangrove swamps, sandy and rocky shores and opens sea front. The number of marine mollusks exceeds 300 species with more than 10 commercially important species. The marine echinoderm fauna comprised of around 80 species while the ancillary resources such as seafans, gorgonids,etc. constitute another 110 species. The state is also endowed with more than 25 species of sea weeds among them 12 species are commercially very important. Mangrove forests in India are habitats of around 177 resident and migratory birds, of which 45 species are reported in the mangrove forests of Kerala alone. The back waters of Kerala is most prominent with more than 70 edible species which include shrimp, mullets, pearl spots, crab,oyster,clam, milk fish, scampi, cat fishes etc. The Pearl spot, Etroplus suratensisis one of the most ideal fin fishes for farming in Kerala(aquaculture species). 

Key Climate Concerns

  • Sea level rise in the Indian seas (Kerala-Cochin): It is projected that it may rise at the rate of 5mm per year in the coming decades. 

Investigations carried out by the CMFRI, Kochi show that different Indian marine species will respond to climate change as follows: 

  1. Changes in species composition of phytoplankton may occur at higher temperature; 
  2. Small pelagics may extend their boundaries; 
  3. Some species may be found in deeper waters as well; and
  4. Phenological changes may occur.
  • Indian mackerel is getting deeper: Besides exploring northern waters, the Indian mackerel Rastrelliger kanagurta has been descending deeper as well during the last two decades
  • Small pelagics extend their boundaries: The oil sardine Sardinella longiceps and the Indian mackerel Rastrelliger kanagurta known for restricted distribution between Malabar upwelling zone along the southwest coast of India are moving to northern latitudes
  • Spawning: threadfin breams like it cool: A shift in the spawning season from warmer to relatively cooler months (from April- September to October-March).