A report of hailstorm damage to two species of freshwater sponge (Demospongiae: Haplosclerida: Spongillidae) populations of West Bengal, India

Abstract

Selected freshwater bodies in Jagaddal of North 24 Parganas in West Bengal, India are inhabited by two species of sponge, Eunapius carteri (Bowerbank, 1863) and Spongilla alba (Carter, 1849) (Porifera: Demospongiae: Spongillidae). Most of these wetlands are perennial ponds without a history of aquaculture and toxin contamination. On 22 March 2014, the entire area of Jagaddal experienced an unprecedented hailstorm associated with a sharp decline of environmental temperature from 35 0C to 21 0C within 10–15 minutes. The hailstorm associated with torrential rain lasted for about 30 minutes. The natural habitat of the sponge was visited after six hours of the hailstorm in open day light conditions. During the field investigation, we recorded large-scale damage to the populations of E. carteri and S. alba. Macroscopic observation revealed that the fragmentation of body masses were also associated with cellular disintegration of the external surface. Sponge cells were experimentally dissociated from the sponge fragments and subjected to dye exclusion assay. A vital dye (trypan blue) exclusion assay of sponge fragments confirmed a high degree of mortality of the cells of E. carteri and S. alba. Hailstorm associated with the decline of environmental temperature down to 21 0C resulted in the mass destruction of these two species of sponges in their natural habitat. Any unprecedented and acute change in the climatic and hydrological parameter may lead to physiological adversity in the freshwater sponge. Subsequently, recovery from cold shock and mechanical stresses was overcome and a regeneration of sponge specimens was recorded within a period of around six months from the date of the hailstorm.