Expedition blogs and news from the Shallow Marine Surveys Group

Sampling at the Ascension Island fishing competition

By Emily Hancox

The final day for most of the team coincided with the annual fishing competition. We arrived at the pier at 11am, to be met with the first fishermen returning with their fresh catches, and a small crowd of spectators.

[caption id="attachment_985" align="alignleft" width="181"]Fish Comp2 Large yellow-fin tuna

Being saved the effort of catching our own specimens, the team rapidly set up an array of scalpels, knives and forceps to process the variety of fish available. The goal was to collect length, weight, sex and maturity information, and to extract the fish ear bones (otoliths) for ageing purposes. A messy business at times, bystanders watched with interest as the borrowed hacksaw was put to use, sawing open fish heads to reveal the otoliths. A small crowd of children became willing assistants, holding little vials and offering enthusiastic advice as the blood, brains and bones occasionally proved challenging to work with. As the sun swang around to glare upon our previously shaded workspace, onlookers “oohed” and “aahed” as the first of the boats returned with their spoils. Huge tuna, the largest weighing 120kg, were craned on to the pier and winched into position to be weighed. After being professionally butchered and sliced into stunning chunks of meat, the heads were available for us, and the saw was back in action.

Fish Comp IMG_1721

The species available for sampling were diverse, different jacks, dolphin fish, moray eels, and wahoo forming a part of the hooked fish that were brought to the table. Remnants of these, and those that were unwanted were rapidly welcomed by the blackfish in the water below.

As people retired to the Saints Club, samples were packed, gear was cleaned and packed, and preparations were made for our imminent departure.

Thanks to all who were involved!

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Things that go bump in the night

By Judith Brown

To get as complete a species list as possible we need to survey different habitats, different seasons and also during the day and at night. Some species remain well hidden during daylight hours when the plethora of fish predators make leaving the safety of the crack or crevice hazardous. When night arrives the seabed is littered by the sleeping bodies of the black fish and out comes a different array of animals. The striking red reef lobster, the small red scorpionfish, giant stretchy yellow banded sea cucumbers, many species of shrimps are just a few who we don’t see through the day. To quantify the difference in species diversity and abundance the SMSG team prepared for some day night comparison surveys.

[caption id="attachment_979" align="alignleft" width="300"]Q66 A (20) Day Quadrat Day Transect

[caption id="attachment_980" align="alignright" width="300"]Q66 B (20) Night Quadrat Night Transect

The survey method was adapted slightly (to compensate for reduced visibility at night) and involved three transects each 1m x 50m survey all along the rocky reef just off Wigan Pier. During the early afternoon Judith, Paul and Martin conducted the first set of transects – leaving the tape measures in situ with activated glow sticks on each end. As darkness fell the divers returned to the pier – Judith with a dive torch strapped to her head to allow her to count and write. This worked well except for that many small amphipods and worms which were attracted to the light at night meaning she had a constant swarm of critters buzzing around her head for the entire dive. Longspine black sea urchin were the most abundant to count with several hundred on each transect but the most exciting critter was an orange nudibranch – usually only found well hidden under rocks. After an 84 minute dive the team were all happy to return to the dive club to a pot of traditional St Helenian pilau cooked by Elizabeth on the BBQ.

[caption id="attachment_978" align="alignnone" width="300"]Q65-66-67 Macros Associated with Night Transects (6) Red Reef Lobster Reef lobster
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Volunteer Ecological Surveyors

By Sarah and Simon Browning

Simon and I have been volunteer divers with the Shallow Marine Survey Group (SMSG) for the last two years and have been privileged to undertake a number of marine research expeditions within the Falklands.

Last year we joined the SMSG Ascension Island expedition bringing with us a small team of the military divers from the Falklands but this year we are by ourselves as volunteers directly supporting the project, our main role to participate in underwater transact surveys, specimen collecting and underwater photography.

130531Q52 and 53 00620130526-Ascension Is_PSII-U 060

Arriving on 24 May, we landed a few days ahead of the main group to enjoy some leave relaxing on this fabulous island.  We took the opportunity to do a couple of dives to check out the camera and more importantly confirm our fish identification skills ready for surveys! The topside of Ascension is equally fascinating and we enjoyed a couple of beach walks beachcombing and watching the blow hole at North East Bay. The evenings were spent on the beach looking for Green turtles and, even though now at the end of the season, after only a few minutes sitting on the beach we saw three laying - amazing. At the same time we saw hundreds of baby Greens scurrying off in to the sea under a full moon and were also very lucky to witness an eruption – truly spectacular seeing so many tiny juvenile turtles pouring out of the sand.

Our leave was soon over with the arrival of the RMS St Helena bringing Jude, Steve and Elizabeth from St Helena. The project swung into action led by Jude with us all out for an afternoon dive off Wigan Pier checking octopus holes, collecting data from settlement plates and assessing general seasonal changes from last August -September. The whole team was assembled by 1 June and since then we have been busy getting involved in all aspects of the project. So far we have  undertaken a number of transact surveys, completed intertidal surveys, collected a number of specimens, helped process samples, revisited the shrimp pools at Shelly Beach and helped with otolith (fish ear bones used for ageing) removal.

20130526-Ascension Is_PSII Simon-U 129

For Simon and myself this trip has given us such a great opportunity to work with eminent marine biologists and in the field. We are looking forward to the next week diving and exploring the rich marine ecology of Ascension…what new species will we discover?

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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.

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We’re back on island - this time with a smaller team of twelve

This the second phase of a SMSG/South Atlantic Environmental Research Institute (SAERI) expedition funded by the Darwin Initiative to examine the marine biodiversity of Ascension Island. Our team of 12 started to arrive on the 24th May. Lt.Col. Simon Browning and Sarah Browning arrived first with our freight. Elizabeth Clingham and Judith and Steve Brown arrived from sunny St Helena on the Tuesday 28th. The rest of us arrived on the 31st May from a cold and blustery Falkland Islands.

Jude's Bath

Lt Col. Browning said “Surprise is a principle of war not logistics! With foresight and good planning everything has come together.” However, our start to the survey was not without its problems. Ascension Island’s dive club’s compressor was out of order. We found this out before the Falkland Islands' component departed so we were able to fly up a portable one.

Fish Chopping1

The objective of this ten day survey is to build on the first by targeting the intertidal  quantitatively, revisiting sites surveyed before to examine the community structure of different habitats on temporal scales and to visit sites and areas not surveyed previously. Efforts so far have already yielded a new species record for Ascension Island, a white spotted octopus (Octopus macropus). This species is active at night and is distributed in the east and west Atlantic but is not known from around Ascension Island. Judith Brown said “It is amazing to see the seasonal changes in fish communities, particularly the small recruitment of juvenile endemic Hawkish.” And Paul Brewin exclaimed “It’s awesome to be back”.

Watch this space – we’ll keep you posted on out progress and discoveries.

Paul's Office

The survey team:

  • Dr Paul Brickle (SAERI/SMSG – Expedition Leader)

  • Dr Judith Brown (SMSG/St Helena Government – Dive Officer)

  • Steve Brown (SMSG – Technical Services)

  • Steve Cartwright (SMSG – Technical Services)

  • Dr Martin Collins (SMSG/GSGSSI – Marine Ecologist)

  • Dr Vladimir Laptikhovsky (SMSG/CEFAS - Marine Ecologist)

  • Lt. Col. Simon Browning (SMSG/BFSAI – Logistics/Marine Ecologist)

  • Sarah Browning (SMSG/BFSAI – Marine Ecologist)

  • Dr Alexander Arkhipkin (SMSG/Falkland Islands Government Fisheries Department - Sclerochronology)

  • Dr Paul Brewin (SMSG/Falkland Islands Government Fisheries Department – Marine Ecologist)

  • Zhanna Shcherbich (SMSG/Falkland Islands Government Fisheries Department - Sclerochronology)

  • Elizabeth Clingham (SMSG/St Helena Government – Marine Ecologist)

  • Emily Hancox (SMSG/SAERI - Marine Ecologist)

As always we are extremely grateful to AIG, particularly Collin Wells (Administrator), Hamish Stewart (Director of Resources), Nicola and Sam Webber and the rest of the Conservation team. We are also grateful to Caz Yon for all of her help.
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Ascension Fireworms

Amphinomid polychaetes are commonly known as fireworms due to the burning sensation once their chaetae (fine 'hairs') break after penetrating our skin; however specimens belonging to only a few genera produces the stinging sensation. They are brightly coloured and can reach quite a large size, up to 50 cm long. Fireworms thrive in intertidal zones and can be abundant in coral reefs or rocky areas, although there are some deep-water genera.

During the dive surveys of Ascension Island the SMSG team found two species of fireworms which have now been identified by Beatriz Yáñez Rivera, of the Universidad Nacional Autónoma de México, as  Hermodice carunculata and Eurythoe complanata.

Hermodice carunculata

The first fireworm recorded from Ascension Island was collected in the middle 1800s. This fireworm is Hermodice carunculata, however at the time it was considered to be another species due to great morphological variation. Now, genetic evaluation indicates that Hermodice carunculata have a broad distribution across the Atlantic Ocean. This species shows ecological adaptations according to habitat conditions and different colouration with low genetic divergence. The population from Ascension Island could be playing an important role in the connectivity between both sides of the Atlantic Ocean.

[caption id="attachment_760" align="aligncenter" width="584"]Hermodice carunculata Hermodice carunculata

Eurythoe complanata

The discovery of Eurythoe complanata represents the first record from Ascension Island. This species has been reported in mainland and some islands of the Atlantic Ocean. These fireworms are common in shallow waters mainly in rocky shores, and they reproduce sexually and asexually. Sexual reproduction involves a rostraria larvae, which has been hypothesized to enable the long-distance dispersal of this species of fireworm.

[caption id="attachment_754" align="aligncenter" width="584"]Eurythoe complanata Eurythoe complanata

- Text by Beatriz Yáñez Rivera

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