FISH YIELD STAUS IN CHILIKA LAGOON DURING POST-HYDROLOGICAL INTERVENTION PERIOD (2001-02 − 2002-03)

Chilika lagoon with high biological productivity is a nature’s bountiful and varied gift of aquatic living resources to mankind. Being influenced by tidal influx from the sea and freshwater inflow from rivers and catchments, the sector, central, southern and outer channel sectors, which are characterised with different & patio temporal salinity pattern fauna. The lagoon has been providing food and livelihood security to more than 1.5 lakh fishers living in its 132 peripheral and island villages.

01 Species Richness(Fishery biodiversity) : 

Fisheries wealth of Chilika lagoon comprises of 323 species(updated record till 2002) which includes 261 fish species, 28 prawns and 34 crab species, from among the large spectrum of fish species prawn and species only 11 groups from fish, 5 species from prawn and only two from crab species are commercially important.

Threatened species and their Re- appearance : 

The incessant anthropogenic pressure and several natural upheavals during the past few decades have altered its natural attributes and in the process the fisheries resources have been the worst causality resulting in declining fish landings and significant transformation of fishery with the replacement of saline migratory species by the uneconomic freshwater species. Under the impact of eco-degradation SIX NUMBER OF ECO-SENSITIVE SPECIES because threatened which were rarely seen in the catches during the last couple of decades, They are namely:

Chanos chanos (Seba khainga)
Megalops cyprinoids (Panialehio)
Elops machnata(Nahama)
Rhabdosargus berda(Kala khuranti)
Hilsa (Tenuealosa) ilisha (ilishi)
Rhinomugil cosula( Kekenda)

The above threatened species have RE-APPEARED in the lagoon after hydrological intervention (eco-restoration meadows) during 2000-01 to 2002-03. Occurrence of their juveniles and adults in the lagoon in the lagoon (captured during seed abundance survey) indicates that their seed incursion into the lake has taken place and their fishery is gradually being established.

02. Status and Trend of Fish, Prawn and Crab Landings during the period of Post Hydrological Intervention :

Before the hydrological intervention during September, 2000, fish landings in the Chilika lagoon fluctuated between 8872 MT (1986-87) and 1269 MT (1995 -96). Similarly, crab landings fluctuated between 141.4 MT (1983-84) and 3.0 MT (1994 -95). After opening of the new mouth and dredging of silt – choked Magarmukh in September, 2000 the fish, prawn and crab landings registered spectacular leap ranging from 93.54 MT to 149.81 MT (crab) during 2000-01 to 2002-03( Table-1, 2 & 3).

Highlights of present fish, prawn and crab landings :

Fish landing during 2000-01 has been the all time high record being 11,,877.81 MT which was most likely due to effective recruitment of fishes from the sea through the new mouth and elevated salinity regime. Although fish landing during 2002-03 was dropped marginally with negative growth of 9.55% as compared to the fish landing in 2001-02, the prawn landing (2478.82 MT) during 2002-03 has registered all time high record (Table-2). Crab landing during 2002-03 has also registered all time high record being 149.81 MT (Table-3). The fish, prawn and crab landings of 2001-02 and 2002-03 are furnished below:

0.3 New Fisheries Research/Investigation Programmes

Three new fisheries investigation programmes have been taken up in Chilika lagoon which have significance in the context of changing ecosystem.

The programme are :

Studies on spawning grounds and seed abundance of fish and prawns in the Chilika lagoon :

Such studies were made 44 years back by the central inland Fisheries Research Institute, Barrackpore (WB). Since the lagoon has undergone massive ecological change during the period habitat attractions, changes in recruitment pattern and seed abundance etc are most likely. Hence a fresh shady is needed. The programme has been initiated since July 2002. Investigations in 4 sectors are carried out under regular monthly programmes.

Till now, spawning grounds of most of the economic fishes have been located and studied. Seasonal abundance and distribution of seeds, spawning season of different species are being studied.

Studies on ecology, potential fishery and biology of Mud crab sp.(Scylla sp.) of Chilika lagoon and their experimental cage culture : 

This ecology and fishery of Chilika crab (Scylla sp.) including their biological aspects were not studied in the past and therefore information on crab fishery, except landing statistics, were not available. This project has therefore assumed importance.

Till now, a 4-month cage culture experiment of two Scylla species (Red mud Green crab of Chilika) has been completed with encouraging results. Computed yield in 6 experimental cages ranged from 2526.66 Kg/ha/4 months to 5826.67 Kg/ha/4 month and survival ranged from 48.89% to 80.0%. Analysing carapace width and body weight date has established the CW_BW equations for Chilika species, Food and feeding habits, sex ratios, fecundity, maturity index, fishery season, fishing methods, seed incursion and abundance studies are in progress.

Migration study of three commercially importance fishes (Mugil uphaus, E.tetra dactylus and Hilsa (Temuralosa) ilisha) through tagging experiment

This programme is to be taken up during the coming winter season, after the ‘Floy-Tanchor’ tags (imported) are procured from a USA company arrangement is being made to import the tags.