Evaluation of growth and production of the threatened giant river catfish, <i>Sperata seenghala</i> (Sykes) in polyculture with indigenous major carps

Abstract

The giant river catfish locally named guizza, Sperata seenghala has significant cultural and economic importance but the fish is now considered as critically endangered due to environmental and manmade interventions in aquatic ecosystem. In order to conserve and rehabilitate this species, an experiment on polyculture of guizza with indigenous major carps was conducted in earthen ponds. Three treatments differing in species ratios and combinations of fish were employed with two replicates each. Treatment-1 (T₁) was stocked with catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala), treatment-2 (T₂) with catla, rohu and guizza (S. seenghala), while treatment-3 (T₃) with catla, rohu, mrigal and guizza. Guizza of T₂ was introduced instead of mrigal in T₁ and 50% of mrigal was replaced with guizza in T₃. The stocking density of fish fingerlings in all the treatments was 7500 individual/ha. Fishes in the experimental ponds were fed with supplementary diet comprising of rice bran (50%), mustard oil cake (30%), fish meal (19%) and vitamin-mineral premix (1%). Physicochemical parameters and plankton populations were within the appropriate levels for aquaculture. Mean growth and survival of catla and rohu were significantly higher in T₂ than in T₃ and T₁. Guizza in T₂ showed higher performances than in T₃, while those for mrigal were higher in T₃ than T₁ (p < 0.05). The total gross and net productions of fishes were higher in T₃ than in T₂ and T₁ (p < 0.05). This trial is a successful attempt to culture the threatened guizza with major carps in earthen ponds, the findings of which would immensely be helpful towards the development of aquaculture and conservation of this important fish in captive condition.

Key words: Riverine catfish, Sperata seenghala, polyculture, earthen ponds.