Impacts of Invasive Fishes on Fishery Dynamics of the Yamuna River, India

Invasion, spread and predominance of alien invasive fishes were studied in 950-km-long stretch of the Yamuna River. The fish yield ranged between 32 t/km/yr to 240 t/km/yr and the catch of alien invasive fishes dominated over local fishes in the fishery, which was over 96% at Etawah. The calculated Invasion Coefficient Index (Ixi) of alien invasive fishes was in the range of 0.12 to 0.31 indicating a major loss to the local fish diversity. The calculated Pearson’s correlation coefficient was found to have positive correlation of 0.757 and 0.710 for common carp and tilapia respectively with locally captured Indian major carps (IMC). The results of this study highlighted how unintentional spread of alien invasive fishes due to rapid aquaculture diversification and intensification has invaded into the Yamuna River causing severe loss to the local fishery. The invasion of alien fishes has been mapped for the Yamuna River at different locations using GIS tools. The results of this study invite attention on the management and sustainability of the local fishery and ecosystem health of the river.

In vivo immunostimulatory effect of the amoebocyte lysate and plasma of Asian horseshoe crab,Tachypleus gigas in a piscine model

Antimicrobial proteins/peptides are becoming a new generation of immunostimulants for prevention and disease control in human and animals,including aquatic animals.As the haemolymph of horseshoe crabs(Tachypleus)contains broad ranges of bioactive compounds,we have explored the in vivo immunostimulating potential of amoebocyte lysate and plasma using a fish model.Indian major carp,Labeo rohita,yearlings were injected intraperitoneally with two doses of lysate and plasma at 50 and 100µg protein per fish.No abnormalities and/or mortalities were recorded in any group.L.rohita injected with 50µg lysate and 100µg plasma protein showed significant enhancement(P<0.01)of various haematological and immunological parameters.There was a significant rise in the total protein and globulin content,myeloperoxidase and respiratory burst activity following injection with 50µg lysate and 100µg plasma protein.The agglutinating and haemagglutinating activities were increased albeit not significantly(P>0.01)in any groups.On the contrary,a significantly high hemolysin titre was recorded in fish that received 100µg plasma protein.Following challenge with Aeromonas hydrophila,both lysate and plasma protein(s)cross protected the fish after 30 days.The highest survival(50%)was recorded in group injected with 50µg lysate protein,followed by 45%in both 100µg lysate and plasma protein injected groups.