Phytal Fauna of <i>Caulerpa taxifolia</i> and <i>C. racemosa off</i> Visakhapatnam coast

Abstract

Littoral phytal fauna of <i>C. taxifolia</i> and C. racemosa of Visakhapatnam coast were investigated during January 1967 to December 1968. The standing crop of <i>C. taxifolia</i> ranged between 0.9 and 1.85 kg/m² of rock surface and that of C. racemosa between 1.4 and 2.8 kg/m². Both the algae were profile during June to October or November and declined from December to April. During May, regeneration of the algae took place. Total non-sessile faunal density fluctuated from 1115.7 to 60053.5/100 g of <i>C. taxifolia </i>and 5643 to 83880/100 g of C. racemosa. The period of high faunal density coincided with (1) degeneration and decline of algae. (2) high degree of sediment accumulation and epiphytation, (3) steady ambient hydrographical conditions, and (4) breeding season of many of the phytal organisms. In general, the faunal density was low when the algae were prolific and the ambient salinity was low. Relatively higher total faunal density of C. racemosa appears to be due to the structural modification of its thallus which provides many minute living spaces for a variety of microscopic organisms. Primary importance of the algal structure in determining the faunal composition and density is discussed. Both in quality and quantity, the local Caulerpa species supported a richer animal life than any of the temperate littoral algae so far investigated. The specific faunal assemblages like the opisthobranchs of the genera <i>Berthelinia</i>, <i>Lobiger</i>, <i>Volvatella</i>, <i>Oxynoe</i> and <i>Cylindrobulla</i> were brought to light along with instances of animal camouflage.