Pacific Oyster, Crassostrea gigas, Cultured With Tilapia, Oreochromis mossambicus×Oreochromis niloticus in a Recirculation System

Abstract

The objective of this study was to evaluate the particulate matter uptake, survival, condition index (CI), and proximate composition of Crassostrea gigas, cocultured in seawater with tilapia. We used three densities of oysters (two, four, and eight) and one control (no oysters) per 150 g of tilapia biomass. Water quality parameters were measured daily, whereas NH 4 -N, NO 2 -N, NO 3 -N, PO 4 , total Kjeldahl nitrogen (TKN), chlorophyll a (Chl a), total suspended solids (TSS) proximate composition and CI of C. gigas were determined at the beginning and at the end of the study. No significant differences in nutrient content were observed between treatments. Significant differences were observed in TKN, Chl a, and TSS between the control and the oyster tanks. Maximum removal percentages were 43.16 for TKN (two oyster treatment), 80.23 for Chl a, and 73.55 for TSS (both in eight oyster treatment). Survival of C. gigas was 100% in all treatments. Significantly higher growth was only observed in two oyster treatment. Protein and carbohydrate content in the oyster tissues diminished in all treatments, whereas lipid increased in treatments with two and four oysters. These results indicate that TSS produced from tilapia can be used as a source of food for C. gigas.

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“…The ammonia level was higher in the control group than in the treatment groups containing mussels, but this difference was not significant (Table 1). Similar results were obtained in previous studies where lower concentrations of ammonia were recorded in ponds containing the mussel E. complanata (Mueller and et al, 2004) and the oyster C. gigas (Miranda et al, 2010), but no significant differences were observed between the treatment and control groups. McKenzie and Özbay (2010) also obtained results similar to ours but reported that ammonia levels occasionally increased significantly in the ponds containing mussels.…”

“…Similar results were obtained for the Pacific oyster C. gigas (Miranda et al, 2010) and the freshwater mussel E. complanata (Mueller et al, 2004;McKenzie and Özbay, 2010), demonstrating that the water quality parameters are not affected by the taxon used for filtration (Mueller et al, 2004).…”

“…This indicates that the ammonia generated by the fish was converted into nitrite but that mussels removed this by filtering the particulate matter in the environment. Similarly, previous studies have found lower nitrite levels in tanks containing the mussel E. complanata (Mueller et al, 2004) and the oyster C. gigas (Miranda et al, 2010), although these concentrations were not significantly different from the control group. In contrast, McKenzie and Özbay (2010) reported higher nitrite levels in the treatment groups containing mussels, although these were also not significantly different from the control group.…”

“…For example, Mueller et al (2004) previously examined the effects of the freshwater mussel Elliptio complanata and silver carp (Hypophthalmichthys molitrix) on water quality and plankton density in partitioned aquaculture systems housing growing catfish (Ictalurus punctatus), and McKenzie and Özbay (2010) examined the use of E. complanata as biomechanical filter in catfish ponds. Miranda et al (2010) also investigated the effects of Pacific oyster (Crassostrea gigas) and tilapia culture on TSS, ammonia, and plankton density in a recirculation system.…”

“…According to the Food and Agriculture Organization of the United Nations (FAO), this trade reached to US$ 1 billion in 2010 (FAO, 2010), with freshwater species representing 90% of this value (Morgan, 2010). The goldfish (C. auratus L., 1758) is one of the most popular and commercial species in the ornamental fish market (Yanar and Tekelioğlu, 1999).…”