Macrobrachium
Giant Freshwater Prawn / Scampi / River Prawn
Introduction
It inhabits freshwater rivers, lakes, and canals, though larvae often require brackish water. It is nocturnal, bottom-dwelling, and highly aggressive, known for its massive growth potential in aquaculture.
Size & Structure
Size: Large-bodied, reaching 30 cm or more in species like M. rosenbergii.
Shape: Elongated, cylindrical body with a rigid cephalothorax and muscular abdomen.
Colour: Greenish-blue to brownish-grey; mature males often have deep blue claws.
Special external features: Characterized by extremely long, powerful second pair of walking legs (chelipeds) and a long, serrated rostrum.
General Features
- Coelom
- Coelomate (Haemocoel)
- Body plan
- Tube within a tube body plan (Protostomous)
- Germ layer
- Triploblastic
- Metamerism
- Metamerically segmented (Heteronomous)
- Body symmetry
- Bilateral symmetry
- Fertilization
- External fertilization
- Digestion type
- Complete (Extracellular digestion)
- Nervous system
- Ganglionated double ventral nerve cord
- Excretory organ
- Antennary glands (Green glands)
- Body temperature
- Poikilothermic (Euryhaline during larval stages)
- Circulatory type
- Open type
- Development type
- Indirect development (Larval stage: Zoea)
- Respiratory type
- Branchial respiration (Gills)
- Mode of excretion
- Ammonotelism
- Circulation system
- Open (Haemolymph flows in sinuses)
- Skeleton structure
- Exoskeleton (Hard, calcareous, and chitinous)
- Level of Organisation
- Organ-system level of organisation
- Regulation of Osmosis
- Osmoregulator (Active ion transport)
Ecology
Dominant benthic predator and scavenger in freshwater ecosystems.
Controls populations of snails and aquatic insects.
Serves as a key food source for predatory fish, wetland birds, and otters.
Economic Importance
Aquaculture: The primary species for freshwater prawn farming (Blue Revolution).
Food Industry: High-value export product marketed globally as Scampi.
Livelihood: Provides significant income for inland fish farmers in tropical regions.