The Romanian Black Sea environment, due to its biodiversity, contains a lot of organism, which represents a rich natural resource of many biologically active compounds, such as: sterols, proteins, polyunsaturated fatty acid, polysaccharides, pigments and antioxidants. In their evolution, marine organisms in the Black Sea adapted excellently to the marine environment such as: low temperature, absence of light, extreme pH and pressure, low salinity, low oxygen, the presence of one toxic abiotic chemical (H2S). Moreover, they produce a wide variety of secondary metabolites (biologically active), which cannot be found in other terrestrial organisms. Chitosan is a copolymer of beta-(1 -> 4)-linked 2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose. Usually, it is obtained by deacethylation of the natural chitin, which is extracted from the exoskeleton of marine organisms, mainly crabs and shrimps. Chitosan could have a lot of applications in biomaterials, pharmaceuticals, cosmetics, metal ion sequestration, agriculture and foodstuff treatment (flocculation, clarification) because of its efficient interaction with other polyelectrolytes. In this paper, we propose new possible source of chitosan, the spawning of Rapanavenosa, a predatory gastropod, which invaded the Black Sea in earlier 1940s. Preliminary spectral studies on this biopolymer extracted from this biomaterial and another marine source (Eriphia verucosa) will be discussed and compared with that of chitosan standard in order to put in evidence the presence of chitosan in the obtained extracts.