How to Identify Silver Jenny

To identify Silver Jenny (Gerres cinereus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Overall silvery, often with faint, dusky vertical bars on the upper flanks, which may be more prominent in juveniles or stressed individuals. Fins are typically translucent to dusky. The dorsal fin may have a dark margin.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Highly protractile mouth, forming a downward-pointing tube when extended., Deeply forked caudal fin., Long, pointed pectoral fins., Large, silvery scales., A prominent, dark blotch often present on the upper operculum (gill cover).

Dorsal fin

Single dorsal fin with 9-10 spines and 10-12 soft rays. The spinous portion is typically higher than the soft-rayed portion.

Tail fin

Deeply forked caudal fin with pointed lobes.

Pectoral fin

Long and pointed, extending beyond the anal fin origin in adults.

Distinctive fins

Anal fin with 3 spines and 7-8 soft rays. Pelvic fins are thoracic, with 1 spine and 5 soft rays.

Identification Tips

1. 1

   Mouth

   Observe the highly protractile mouth, which can extend downwards to form a tube for sifting through substrate. This is a key characteristic of the Gerreidae family.

2. 2

   Coloration

   Note the overall silvery body. Look for faint, dusky vertical bars on the upper flanks, which can be more or less visible depending on the individual and its environment. A dark blotch on the operculum is often present.

3. 3

   Fins

   Examine the long, pointed pectoral fins that often reach past the origin of the anal fin. The caudal fin is deeply forked. The dorsal fin has a prominent spinous portion.

4. 4

   Body Shape

   The body is laterally compressed and relatively deep, typical of mojarras.

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