bigfish Spotters ID Guide

A summary of the distinctive features of the bigfish species are shown below. This info is also available for PDF download as the Spotters Guide.

Whale shark (Rhincodon typus)

1. Unique colour pattern of white spots and stripes on dark background.
2. Dorsal fin triangular, upright, to 1.2 m tall.
3. Vertical tail fin, up to 3 m tall; no tail notch.
4. 3 strong ridges along each side.
5. Broad, flattened head, wide slit-like mouth, to 1.5 m wide.
6. Usually 6?12 m long, but to 18 m.

Basking shark (Cetorhinus maximus)

1. Blue-grey to brown-grey above, paler below.
2. Large, rounded dorsal fin.
3. Vertical tail fin has notch on upper lobe.
4. Gill slits almost encircle the head.
5. Mouth extends under and behind the eyes.
6. Usually 7?9 m; to at least 10 m.

Areas to photograph for ID, left side best, then right side; also any distinctive marks or scars on the body.

Spine-tailed devil ray (Mobula japanica)

This is the most common species of mobulid in New Zealand.

1. Iridescent purple-black above, juveniles with pale shoulders fading in adults, white below; dorsal fin with conspicuous white tip.
2. Head narrow, ? 22 % body width; mouth underneath; short head fins, resembling horns when not feeding.
3. Spiracle on side of head, below level of wings.
4. First gill slit well behind leading  edge of wing.
5. Whip-like tail long, longer than body when intact, with short functional spine.
6. To at least 3.1 m, usually smaller.

Manta ray (Manta birostris)

1. Dark above, pale shoulders and V-mark in front of dorsal fin, mostly white below; some individuals almost all black; dorsal fin without white tip.
2. Head broad ? 24 % of body width; mouth terminal; long head fins, resembling horns when not feeding.
3. Spiracle on top of head, visible from above.
4. First gill slit at or slightly
5. behind leading edge of wing.
6. Whip-like tail short, similar length to body when undamaged, with prominent round knob containing vestigial spine just behind dorsal fin.
7. To at least 6.7 m wide, sightings to 7.9 m in NZ.

Areas to photograph for ID, underside (ventral) best, then top (dorsal); also any distinctive marks or scars on the body.