Abstract
(1) Exploring the potential impacts of Mactra veneriformis and Ruditapes philippinarum on the aquaculture of Meretrix meretrix in the tidal flat aquaculture zone is significant for the optimization of bivalve aquaculture structure. (2) In this study, we systematically compared the differences in feeding, metabolic physiological indicators, and energy budgets of the three bivalve species in the M. meretrix aquaculture zone of Rudong County, Jiangsu Province, under the feeding conditions of Isochrysis zhanjiangensis and Platymonas helgolandica. (3) The results indicated that feeding with I. zhanjiangensis could significantly improve the feeding efficiency of the three bivalve species, and M. veneriformis showed the strongest feeding ability. Under I. zhanjiangensis feeding conditions, the clearance rate [1.373 ± 0.177 L/(g·h)] and ingestion rate [9.803 ± 1.264 mg/(g·h)] of M. veneriformis were significantly higher than those of M. meretrix [clearance rate: 0.716 ± 0.046 L/(g·h); ingestion rate: 5.112 ± 0.328 mg/(g·h)] and R. philippinarum [clearance rate: 0.609 ± 0.101 L/(g·h); ingestion rate: 4.351 ± 0.725 mg/(g·h)] (p < 0.05). In terms of energy allocation, the scope for growth (SFG) of M. veneriformis [133.050 ± 15.705 J/(g·h)] was significantly higher than that of the other two bivalve species. M. meretrix [70.550 ± 2.133 J/(g·h)] had the highest energy utilization efficiency, while R. philippinarum [53.688 ± 7.548 J/(g·h)] had the lowest SFG due to high excretion losses. (4) In conclusion, M. veneriformis shows high production potential in the aquaculture system, and its potential impact on M. meretrix is greater than that of R. philippinarum, thus requiring close attention in aquaculture management.