Institute of Fundamental Technological Research

The aquaculture of Argopecten purpuratus (Peruvian scallop) is a profitable activity with positive impacts on the local economy. However, the development of biofouling on the culture lantern nets generates negative environmental impacts that affect its sustainability. A feasible option aimed at reducing the development of biofouling is to increase the frequency of lantern nets exchange. In this study, we tested whether doubling the lantern net exchange frequency in the final phase of culture reduces biofouling and, in turn, improves the growth and survival of A. purpuratus. For this purpose, in the concession of a company dedicated to the cultivation of A. purpuratus in Samanco Bay, Peru, four 10-floor lantern nets were placed at 25 organisms per floor, divided into two treatments (T1 and T2) with two replicates. One group of these (T1) was exchanged after 30 days, and another group (T2) was maintained until harvest. As a result of the lantern nets exchange, biofouling weight was reduced by 64.6%, survival improved by 10.8%, gonad weight increased by 52.5%, and adductor muscle weight increased by 62.4%, which represents an additional net income of 6582.58 US$ per ha. This study demonstrates the significant benefits of regular lantern net exchanges in mitigating biofouling and enhancing the overall yield and economic viability of A. purpuratus culture, contributing to the advancement of more sustainable aquaculture practices.

Argopecten purpuratus, biofouling, lantern nets, marine cultivation, profitability

Argopecten purpuratus, a mollusk very cultivated in Peru, is a species whose ecological relations with respect to the epibionts that colonize it are not well known. For that reason, the objective of this research was to determine the effect of epibionts on valvar growth, total weight, gonad weight, adductor muscle weight, and survival of this cultured species in Samanco Bay. Four lanterns of 2 m and 10 floors were placed with 25 organisms, of 7 cm each, per floor, in two treatments: with epibiont removal (T1) and without removal (T2). The data was obtained after harvest, and the epibiont species on the right and left valves were identified and quantified in T1 and T2. In addition, the Absolute Growth Rate (AGR) was calculated for the meristic records, and the t Student test was applied to compare averages. Furthermore, mortality was recorded at harvest. The analyses allowed the identification of 43 epibiont species, 3 of them endolithic. The greatest biomass is of filter feeders: 70.1% in T1 and 90.9% in T2, and concentrated in 4 species, with limited development in T1. The biomass on the right valve at T1 and T2 represented 80.7 and 151.8% of the weight of the organism, respectively, and on the left valve 89.3 and 95.1%. All Absolute Growth Rates at T1 were higher than at T2, although without statistical significance. Mortality at T1 and T2 was negligible. This research has determined that the epibionts S. patagonicus, C. intestinalis, Hidroydes sp., and B. neritina, qualified as engineered species, are the predominant species on A. purpuratus in suspended cultures. Likewise, treatments with epibiont removal showed a lower development of these and 39 other associated species of lesser importance in terms of number and biomass. Our results allow us to infer that the development of epibionts can generate important stress in A. purpuratus, resulting in losses in the profitability of companies dedicated to this activity.

Argopecten purpuratus, Aquaculture, Epibiosis, Biofouling, Bivalve