Estudo do substrato preferencial do caranguejo do género Uca

Abstract

Among the physical characteristics of a substrate, texture and structure are important because of their action on aeration and moisture retention, with regard to chemical properties, the acidity index (pH) stands out due to its effect on the availability of nutrients. Several factors influence the distribution of crabs and among them the granulometry is evident as one of the most important factors, directly determining the type and quantity of the organisms that compose it and indirectly the quality of available food. The present work entitled Uca Crab Preferred Substrate Study was carried out on the basis of a laboratory experiment to determine the crab burial capacity and to analyze the foraging behavior in three substrates. The experiment consisted of the use of three plastic tanks filled with clayey substrates (lower area) r, sandy clay loam (middle area) and sandy francs (upper area). Each tank had six replicates (experimental units), using estuary water to maintain moisture, the experiment had 60 samples. In the granulometric analysis, the sediments of the lower area presented composition of 55.61% of clay, 36.01% of slime and 8.37% of sand, those of the average area presented composition of 27.95% of clay, 10.60% of slime and 61.44. % sand and the upper area presented composition of 15.76%, 16.24% and 67.99%, respectively. The Uca crab preferred the clayey substrate for the construction of its burrows as well as foraging, decreasing its ability to dig and feed on larger-sized sediments. The burial capacity of the Uca crab on the three substrates was significantly different (p <0.05 F = 12.24) and no significant differences were observed in the foraging behavior of these crabs. foraging of crabs between substrates (p> 0.05 F = 0.15, p> 0.05 F = 0.12 and p> 0.05 F = 2.13) respectively.