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Some interesting
Hawaiian octopuses not yet "officially" known from Hawai`i
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CRESCENT SPOT
OCTOPUS
Abdopus sp.
A small, fist-sized octopus typically
seen after sunset on shallow reef flats and down to about 30 ft.
Usually dark or mottled, the arms usually banded with white, the
suckers orange (both characters clearly visible on photo 2). The
suckers have scalloped (crenelate) edges on mature animals. Named
for two pale, crescent-shaped spots often visible on the mantle
about mid-distance from the eyes and the mantle tip (visible on
photo 1, right center).
This
animal has been called Octopus hawaiiensis in the literature,
but the type specimen of hawaiiensis is in poor condition
and it is unclear exactly what species it represents. Christine
Huffard has collected and examined numerous specimens of this octopus
in recent years; she places them in the genus Abdopus. Thanks
to Adam Daw, Cory Pittman, and Christine Huffard for helping with
the IDs of these photos, which were taken at night off Makaha, O'ahu,
at a depth of about 25 ft.
In older editions of my book
Hawaii's Sea Creatures, the "Crescent Octopus"
photo on p. 199 actually depicts the Round Spot Octopus, below.
This was corrected in the 10th printing (2022).
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ROUND SPOT OCTOPUS
Octopus cf.
vitiensis
This
octopus occupies much the same shallow habitat as the Crescent Spot
Octopus, above, but is smaller, lighter in color, more finely patterned,
and generally less common. Its arms are more slender and its suckers
are cream colored with smooth edges. It often displays two round
spots on the mantle, hence the common name (clearly visible in photo
1). It is active mainly at night, emerging around dusk, but specimens
have been collected during the day in a shallow, completely dark
cave.
In older editions of my
book Hawaii's Sea Creatures, the photo labeled "Crescent
Octopus, Abdopus sp." on p. 199 is actually this species
and not the true Crescent. The error was corrected in the 10th printing
(2022).
Thanks to Adam Daw, Cory
Pittman, and Christine Huffard for helping with the IDs of these
photos, which were taken at night off Black Point, O'ahu, at a depth
of about 3 ft.
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BLUE OCELLUS
OCTOPUS
Octopus sp.
Hawai`i
has 15 named octopus species and this does not seem to be among
them. The first one I saw was on the wreck of the Mahi off leeward
O`ahu. Lisa Kasnell alerted me to it and sent a photo showing a
distinct bluish ring. It was fist sized, stretched out, maybe a
foot across, she said. We visited the Mahi and it was still there,
in the opening of a pipe sticking up from the deck. We got it out
and clipped a tiny DNA sample from a tentacle tip which we sent
to Crissy Huffard at UCLA Berkeley. I
thought it might be a young Octopus cyanea ("Day Octopus")
but the DNA eventually came back as
related to cyanea, but different
Not long after, I saw another in a deep cave-like
crevice off the Lana`i Lookout, O`ahu, at a depth of about 25 ft.
and managed to get a photo (photo 2, above). Though I've been back
to the same crevice several times, I never saw it again. The next
sighting was in August just off the beach at Makua, O`ahu, under
a ledge in about 8-10 ft. (photo 1, above). On the basis of these
three sightings, it seems these octopuses are out during the day
but remain in dim sheltered areas and do not roam about as Octopus
cyanea does. If you see / photograph any interesting behaviors
that might be useful to whoever in future describes this animal
scientifically, don't hesitate to pass them on!
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Abdopus abaculus?
Pauline Fiene
found this octopus with long thin arms at Haloa Point, Maui, in
2008. She sent the photo to Christine Huffard, who replied: It
looks like it's either Abdopus abaculus (very long arms,
fairly shallow- so far found as far east as Moorea) or my runner
up guess Octopus gorgonus (described from Tonga, known so
far also from Indonesia and Moorea).
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HAIRY OCTOPUS
Octopus sp. 16
Pauline Fiene writes: I found this in July 2013 at about 45 feet
off Wailea Point. It was about the size of a dime, so fast, and
displayed such a variety of postures. I wished I'd had my better
camera or video. It looks like this species is on page 300 of Mark
Norman's Octopus book and also I see quite a few photos of it online
- if it's the same species. Crissy Huffard said that as far as she
knows this species has not yet been described and has not been previously
reported from Hawaii.
UPDATE: In July 2021 Roney Rodrigues sent me this great shot of
a Hairy Octopus he found off west O'ahu. He estimates the size as
about 7 mm (see bottom photo with tip of car key for scale). Roney
posted more photos on iNaturalist
and Crissy Huffard confirmed the ID.
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