Potential of Tegula atra (mollusca: Gastropoda) as bioregulator of algae growth in culture tanks of the chilean flounder Paralichthys adspersus

Abstract

One of the main problems in aquaculture lies in the stress to which the species in cultivation can be subjected, therefore the development of alternative techniques such a mixed culture are beneficial to minimize stress and improve the industry. Tegula atra is a gastropod that lives in subtidal and intertidal, with local economic importance and due its herbivorous behavior, we hypothesized that T. atra may be valuable in controlling macroalgae growth in culture tanks by mixed culture. Grazing percentage, respiratory behavior and excretion of nitrogen wastes, were measured in three size classes of T. atra, which were maintained in mixed culture together with the economically relevant Chilean flounder. While the largest specimens of T. atra (Class 3) were the most efficient in terms of algae consumption, the other classes were less effective and did not show significant differences in each other within a 24-hour period. Smaller and larger size classes organisms (Class 1 and Class 3), consumed the greatest amount of oxygen within a period of 120 min. Finally, smallest organisms (Class 1) emitted the greatest nitrogen wastes, in a period of 120 min. As the grazing ability was higher in larger specimens (Class 3), they could be the ideal candidates for polyculture. However, medium-sized specimens (Class 2) may be the most suitable, due its low O2 consumption and lower excretion of NH3, producing less negative effect on water quality. Future studies should evaluate the potential negative impacts of T. atra on the physiology of its cohabitants.