Preliminary Evaluation of Pooled Respirometry for Estimating Oxygen Consumption in the Freshwater Shrimp Neocaridina denticulata (Crustacea: Decapoda: Atyidae)

Metabolic rate is closely linked to body mass and is widely used to relate physiological processes to ecological and evolutionary patterns. In small aquatic organisms, measurements of oxygen consumption rate (Mo2) are often limited by instrument sensitivity. Although pooled respirometry is commonly used as a practical alternative, its reliability remains insufficiently evaluated in small freshwater invertebrates. This study examined measurement consistency among respirometry approaches and explored the relationship between body mass and metabolic rate in the freshwater shrimp Neocaridina denticulata. Oxygen consumption rate was measured in single individuals and pooled groups of three and five individuals. No significant differences were detected among treatments (one-way ANOVA, p > 0.05), and estimates were generally comparable across methods. Metabolic rate increased with body mass (R2 = 0.746), and log–log regression yielded a scaling exponent of 0.99 (95% CI: 0.75–1.22), indicating an approximately isometric relationship. Overall, pooled respirometry produced results comparable to individual measurements. Within the experimental range examined, pooled respirometry provided reliable metabolic estimates without detectable systematic bias. These findings provide preliminary experimental support for pooled respirometry as a practical approach for metabolic measurements of small N. denticulata within the experimental conditions examined, particularly when individual measurements are constrained by instrument sensitivity.