Expedition blogs and news from the Shallow Marine Surveys Group

Black triggerfish anecdotes

By Dr Martin Collins

It’s great to be back on Ascension and a particular treat to exchange the cold winter waters of the Falklands for the tropical seas surrounding Ascension.

Yesterday morning myself, Stevie Cartwright, Steve Brown, Elizabeth Clingham & Sarah Browning visited a new site off a headland between Comfortless Cove and Long Beach.   We were diving from Caz Yon’s RIB (thanks Caz) and Stevie and I were tasked with taking macro photographs and collecting invertebrate specimens, focusing on species that we had not previously encountered.

We dropped down to 10 m and, as usual, found an abundance of the black triggerfish (Melichthys niger). Our quest was for invertebrates, but as we turned over rocks to expose the cryptic fauna, we were surrounded by clouds of black triggerfish, who were snacking on anything that we exposed.  The black triggerfish are not fussy eaters and whilst I was using my ninja-like skills to capture small, but remarkably agile octopus, I heard a squeal from Stevie, whose ear was being nibbled by a blackfish.  Unfortunately for Stevie the little bit of blood drawn by the first bite only served to attract more black-fish and Steve was quickly surrounded.  Steve initially tried to fend them off, but his ears offered an exposed and tasty treat and he was forced to cover them with his mask strap to avoid further damage.

the Usual Balckfish

The little octopus was less than two cm long, maybe a white-spotted octopus (Octopus macropus), which will be new record for Ascension.  Jude saw an adult white-spotted octopus on a dive last week. The octopus has been preserved and will be sent an expert for a confirmation on its identification.

After the days diving and whilst dinner was cooking on the barbecue, eight of us headed out for a night dive off Wigan Pier, in English Bay.  Night dives on Ascension are fantastic and the contrast between night and day is incredible.  At night the black triggerfish that normally nibble on anything that move are found lying on their sides asleep, allowing all the invertebrates to come out and forage.   On this dive Steve Brown and Paul Brewin saw one of the largest invertebrates, a crayfish, catching and consuming a black-triggerfish.   As usual Paul Brewin described it as “Awesome” – I think he needs a new superlative.

Cray Blackfish

The final highlight of the day was emerging from the night dive on the beach at English Bay to see newly hatched turtles making their way to the sea.  One unfortunate turtle’s journey was abruptly curtailed by a “Sally lightfoot” crab that we spotted with a turtle in its claws, but plenty more made it to the sea – the first stage of their long journey to the feeding grounds off Brazil.

The Elusive Parrotfish
Volunteer Ecological Surveyors

Comments 1

Guest - Simon Plummer on Monday, 10 June 2013 18:50

An enjoyable and funny read, thank you steve for making me chuckle.

An enjoyable and funny read, thank you steve for making me chuckle.
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Saturday, 22 June 2024

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