Integrated multitrophic aquaculture (IMTA), the farming of fed aquatic animal species, in combination with extractive species (organic and inorganic) in earthen ponds seems to be an important alternative production system for Southern Europe. By creating a balanced system for environmental sustainability while increasing the profitability and social acceptability of aquaculture, IMTA in earthen ponds might contribute to increase product diversification and valorisation by seafood certification. In earthen ponds IMTA water quality of the system depends on the rehabilitation of wastes by the trophic relations between farmed species. Previous study by this research group1 showed that the presence of oyster enhanced system water quality and improved meagre performance when compared with systems without oysters.
Dissolved oxygen was by far the most important and critical parameter, since oxygen plays a crucial role on fish oxidative metabolism. Haematological parameters (haematocrit and haemoglobin) provide important insights on fish oxygen metabolism.
The aim of this study was to assess how the water quality from distinct combinations of trophic levels (Fish + Oysters + Macroalgae; Fish + Oysters; Fish + Macroalgae) influenced the haematological parameters of meagre along the experimental period, and consequently their physiological conditions.
Meagre blood samples collected monthly during experimental period (May to November) were used to determine several haematological parameters (haematocrit, haemoglobin, number of red cell).
Haematological parameters of meagre under Fish + Oysters and Fish + Macroalgae conditions exhibited higher fluctuations for some of the haematological parameters, when compared to meagre from Fish + Oysters + Macroalgae that exhibited higher stability of the parameters. This analysis indicate that Fish + Oysters + Macroalgae was a better combination of trophic levels in pond IMTA.
Acknowledgments: Research funded by project DIVERSIAQUA (16-02-01-FEAM-66 MAR2020, Portugal) and IMTA-Effect (ID 976 - IMTA-EFFECT, COFASP).
1Cunha et al. 2019. Aquaculture: doi.org/10.1016/j.aquaculture.2019.734297