Routine respiration and activity of the Indonesian mangrove crab, Scylla serrata (Forskål, 1775) (Decapoda, Brachyura)

• Published in: Crustaceana 2007, Vol.80 (1), p.77-95
• Main Authors: Kunzmann, Andreas, Schmid, Michael, Yuwono, Edy
• Format: Article
• Language: English
• Subjects: Brachyura; Brackish; Crabs; Decapoda; Marine; Marine fishes; Metabolism; Mud; Oxygen; Oxygen consumption; Respiration; Respirometers; Salinity; Scylla serrata; Tropical fishes
• ISSN: 0011-216X; 1568-5403
• DOI: 10.1163/156854007779696532

For the first time baseline respiration and activity were determined simultaneously for 13 specimens of the mangrove crab, Scylla serrata. Experiments were conducted in an intermittent-flow respirometer at 22°C, ambient salinity S = 30, and low light conditions (red light, 5 W). Permanent measurements of crab activity by an infrared video system (number of movements) and oxygen consumption were coupled, allowing to determine both the routine (ROC) and standard oxygen consumption rate (SOC). The experimental setup allowed the calculation of activity, by recording single movements. Relative ROC values varied between 70 mg O₂ $\text{h}^{-1}$ $\text{kg}^{-1}$ wet mass (WM) for a large (285 g) specimen and 170 mg O₂ $\text{h}^{-1}$ $\text{kg}^{-1}$ WM for a small (37 g) specimen. Activity rates varied between 3216 movements $\text{h}^{-1}$ and five hours without any movement. Mean movement rates were between 14 and 165 $\text{h}^{-1}$ and mean rest rates between 2 and 23 min. Absolute ROC for a standard mass of 50 g was calculated to be 4.72 mg O₂ $\text{h}^{-1}$ , using a wet mass vs oxygen consumption relationship of ROC (mg O₂ $\text{h}^{-1}$ ) = 0.1525 × $\text{WM}^{0.8772}$ (R² = 0.92). This is up to 2.5 times the oxygen consumption of a 50 g scorpion fish measured with the same method, and much higher than previously assumed. In spite of frequent resting times, it was not possible to find statistically significant differences between oxygen consumption at rest and during activity. The mangrove crabs investigated were more active than expected. Apparently, metabolism of crabs is on a generally higher level, which already includes spontaneous activity. This seems to be the result of a specialized mode of life in tide-regulated mangrove areas. /// Ruheatmung und Aktivität wurden zum ersten Mal simultan für 13 Individuen der Mangrovenkrabbe Scylla serrata bestimmt. Die Experimente wurden in einem intermittent-flow Respirometer bei 22°C, natürlicher Salinität (S = 30) und bei wenig Licht (Rotlicht, 5 W) durchgeführt. Permanente Aufzeichnungen, sowohl der Krabbenaktivität durch ein Infrarot-Videosystem (Anzahl der Bewegungen), als auch des Sauerstoffverbrauchs, wurden gekoppelt, so dass Routine- (ROC) und Standardsauerstoffverbrauch (SOC) ermittelt werden konnten. Der Versuchsaufbau ermöglichte die Berechnung der Aktivität durch das Aufzeichnen von Einzelbewegungen. Relative Sauerstoffverbrauchswerte (ROC) variieren zwischen 70 mg O₂ $\text{h}^{-1}$ $\text{kg}^