How to Identify Cutthroat Eel

To identify Cutthroat Eel (Synaphobranchus kaupii), look at these key features.

Physical Characteristics

Body shape

eel-like

Coloration

Typically dark brown to black, sometimes with a purplish or grayish tinge, allowing for camouflage in the deep-sea environment. The fins are often darker than the body.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Large, crescent-shaped gill openings that extend ventrally, giving the appearance of a 'cut throat'., Absence of pectoral fins in adults (though rudimentary ones may be present in juveniles)., Small, embedded scales that are often difficult to discern., A relatively short snout with a large mouth extending beyond the eye.

Dorsal fin

Long, originating well behind the head and confluent with the caudal and anal fins.

Tail fin

Confluent with the dorsal and anal fins, forming a continuous fin fold.

Pectoral fin

Absent in adults, or greatly reduced and rudimentary in juveniles.

Distinctive fins

The continuous dorsal, caudal, and anal fin structure is characteristic of many eels, but the absence of pectoral fins in adults is a key distinguishing feature for Synaphobranchus kaupii.

Identification Tips

1. 1

   Gill Openings

   Look for the prominent, crescent-shaped gill openings that extend significantly onto the ventral surface of the head, giving the 'cutthroat' appearance. This is the most reliable distinguishing feature.

2. 2

   Pectoral Fins

   Confirm the absence of pectoral fins in adult specimens. If present in juveniles, they will be very small and rudimentary.

3. 3

   Body Coloration

   Note the uniform dark brown to black coloration, typical of deep-sea species.

4. 4

   Scales

   Observe the presence of small, embedded cycloid scales, which may require close inspection or magnification to see clearly.

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