Commerson's Anchovy (Larval stage)
Stolephorus commersonnii
Type: saltwater, pelagic, estuarine
Physical Characteristics
Elongated, slender body that is nearly transparent in the larval stage. Displays a prominent line of melanophores (dark pigment spots) along the ventral Surface. Large prominent eyes and a developing sub-terminal mouth typical of the Engraulidae family. Fins are just beginning to develop their definitive ray structures in these specimens.
Habitat & Distribution
Found in coastal marine waters, lagoons, and estuaries across the Indo-West Pacific, including Sri Lanka. Adults prefer muddy-bottomed areas while larvae are common in plankton-rich surface waters of lagoons.
Size & Weight
As larvae, they are several millimeters long. Adults typically reach 10 cm, with a maximum length of approximately 14 cm.
Similar Looking Species
Encrasicholina devisi (Devis's anchovy) and Stolephorus waitei. Distinguished in larval stages by the specific count and distribution of ventral melanophores and myomere count.
Ecological Role
A vital part of the food web, acting as a primary consumer of zooplankton and a major forage base for larger predatory fish, sea birds, and marine mammals.
Diet
Primarily zooplanktivorous, feeding on small crustaceans like copepods, and other planktonic organisms using gill rakers to filter water.
Behavior
Schooling species that exhibits diurnal migrations; larvae are often found in the upper water column of lagoons during ichthyoplankton surveys.
Reproduction
Iteroparous spawners with high fecundity. They release buoyant eggs into the water column; larval development is rapid to minimize predation risk in the plankton layer.
Conservation Status
Least Concern (IUCN); population is generally stable although susceptible to fluctuations in coastal water quality and overfishing of forage bases.
Identification Tips
Look for the distinctive straight line of ventral pigment spots and the elongated, glassy body shape. Large eyes relative to the head size are a key larval feature.
Interesting Facts
These fish are highly sensitive to salinity changes, often moving deep into lagoons during high-tide cycles to find optimal breeding conditions. Their прозрачный (transparent) larval state is an evolutionary defense against visual predators.
User Notes
From Sri Lankan lagoon ichthyoplankton survey
Identified on: 5/20/2026
Mode: Standard