How to Identify Milk Shark

To identify Milk Shark (Rhizoprionodon acutus), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Dorsal surface typically grey to grey-brown, sometimes with a bronze sheen, fading to white or pale grey on the ventral side. Fins may have dusky tips, especially the pectoral and dorsal fins. No prominent markings.

Scale type

placoid

Mouth position

inferior

Distinctive features

Long, pointed snout, longer than the mouth is wide., Large, circular eyes., Small, triangular, oblique teeth with smooth or finely serrated edges., First dorsal fin originates over or slightly behind the free rear tips of the pectoral fins., Second dorsal fin is relatively small and originates over the anal fin., No interdorsal ridge.

Dorsal fin

Two dorsal fins. The first is moderately large, triangular, and originates over or slightly behind the pectoral fin free rear tips. The second dorsal fin is much smaller, originating over the anal fin.

Tail fin

Heterocercal caudal fin, with a well-developed ventral lobe and a prominent subterminal notch on the upper lobe.

Pectoral fin

Moderately long and falcate (sickle-shaped).

Distinctive fins

No interdorsal ridge present between the dorsal fins.

Identification Tips

1. 1

   Snout

   Look for a distinctly long and pointed snout, which is longer than the width of the mouth.

2. 2

   Eyes

   Observe the large, circular eyes, which are characteristic of the species.

3. 3

   Dorsal Fins

   Note the position of the first dorsal fin, which originates over or slightly behind the free rear tips of the pectoral fins. The second dorsal fin is small and originates over the anal fin.

4. 4

   Interdorsal Ridge

   Confirm the absence of an interdorsal ridge between the two dorsal fins, a key distinguishing feature from some other requiem sharks.

5. 5

   Coloration

   The grey to grey-brown dorsal coloration fading to white ventrally, often with dusky fin tips, is typical.

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