Food and faeces settling velocities of meagre (Argyrosomus regius) and its application for modelling waste dispersion from sea cage aquaculture
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AuthorsPérez, O.; Almansa, E. (Eduardo); Riera, R.; Rodríguez, M.; Ramos, E.; Costa, J.; Monterroso, O.
Particulate wastes (uneaten feed and faeces) are assumed to cause the most intense impact on the benthic community beneath aquaculture cages. Settling velocity of uneaten feed pellets and faecal material, required as model input data, represents a key parameter for waste dispersion models. In this study, settling velocity rates of two commercial meagre (Argyrosomus regius) feed pellets (EFICO Sigma 578 — Biomar 9 and 12 mm) and faecal material from two size categories of cultured meagre (small: 0.821 ± 0.157 kg; large: 1.663 ± 0.371 kg) were determined. Settling velocity for Biomar 9 and 12 pellets followed a normal distribution, with mean values of 9.83 ± 0.17 cm s−1 (n = 78) and 9.67 ± 0.28 cm s−1 (n = 76) respectively and 9.75 ± 0.24 cm s−1 for all data (n = 154). On the contrary, faecal particle settling velocity data did not comply with normal distribution assumptions. Settling rates were not significantly different (P = 0.37) between the two meagre size categories, but ...