Marine biodiversity of the Southwest Pacific amazes.
After an intrepid six weeks at sea the South West Pacific Expedition concluded in early September. For this voyage AMRI scientists, Mark McGrouther and Sally Reader (Fish Collection); Steve Keable, Elena Kupriyanova and Anna Murray (Marine Invertebrates Collection); and Mandy Reid (Malacology Collection), joined international colleagues in undertaking biological surveys and genetic sampling aiming to compare the biodiversity, population connectivity and community structure of marine environments in the outer reefs and islands of New Caledonia, Fiji and Tonga.
During the expedition the team was based on board of the Research Vessel Braveheart which made a more than 5,000 kilometre round trip from its base in Tauranga, New Zealand, to Noumea then Suva and back via the Lau Islands, Minerva Reefs and the Kermadec Islands.
Along the way there was plenty of opportunity for hand-collecting while scuba diving, the main sampling technique of the voyage, with two dives a day being the usual routine. In total the group logged 90 dives in habitats ranging from shallow reef flats and lagoons to deep, steeply sloping reef fronts. Diving was supplemented with intertidal collecting, baited traps, and use of a light at night to attract fishes and invertebrates which were captured with a net.
At times the diversity of both the fishes and invertebrates was overwhelming leading to some very late nights to sort, catalogue and preserve the specimens.
The Australian Museum invertebrate team members focused particularly on crustaceans (such as crabs and shrimp), marine worms and molluscs (including snails, bivalves, octopuses, nudibranchs) for research projects currently underway and as a reference for future study.
Steve noted a highpoint for him wasn’t necessarily the diving (spectacular though it was) but some of the intertidal collecting. He commented, “We were privileged to be able to visit the intertidal flats at Ogea Levu, in the southern Lau Island Group, Fiji. Apart from being visually spectacular, with lots of little islands that were eroded in the intertidal area so they appeared to be growing on stalks like mushrooms, the biodiversity was amazing. I’m used to temperate areas, here I was seeing more species than I could count. I’m optimistic that the data we collected will help feed into conservation efforts underway in the region”.
Among the crustaceans, highlights included several mantis shrimp (Stomatopoda) that were collected using a suction pump from burrows on sediment flats at low-tide. The remote location and unusual sampling method suggest these will provide valuable new information for studies examining the distribution and relationships of these animals. Beach hoppers (Amphipoda: Talitridae) were another notable find on intertidal sand beaches throughout the Lau Islands in Fiji. These small crustaceans lack a larval stage for ready long-distance dispersal on ocean currents, so how they become widely distributed is poorly understood. The identity of those found during the expedition will be significant in piecing together links across the broader Pacific. Additionally, many types of shrimp were collected, particularly snapping shrimp, and it is likely there will also be some important finds among these when they are fully classified.
A great variety of marine worms were numerous in many locations but these soft-bodied animals were mostly well hidden from potential predators inside the sediment or under rocks. To collect them, divers often had to not only turn rocks but compete with fishes trying to eat the exposed worms! Of the worms obtained, those of particular interest for AMRI specialists include species inhabiting calcareous tubes such as the brightly coloured Christmas tree worms (family Serpulidae), beautiful fan worms inhabiting soft silty tubes (Family Sabellidae) and spaghetti worms (Family Terebellidae) that spread their long feeding tentacles widely.
Mandy is eagerly awaiting the arrival of the mollusc specimens in Australia. Although a wide array were collected not many cephalopods (her specialty which includes octopus and squid) were included, so it makes those that were all the more precious! The octopuses gathered during the expedition are relatively small, and difficult to identify without all the reference materials, so we can’t be sure yet exactly what they are but at the very least expect they will be new distribution records from this part of the Pacific.
Mark and Sally were delighted to be able to share some of the labour intensive tasks and expertise of catching, identifying, labelling, photographing, tissue-sampling and preserving the fish specimens discovered during the expedition with their colleagues from New Zealand. Mark observed that the fishes obtained from these remote areas help fill in some knowledge gaps, remarking “Many are the first records for the region and we were excited to see some we couldn’t recognise in the field, which may be new species. More work needs to be done to confirm this so we will call on assistance from our network of experts around the world to help. Either way, the specimens comprise a valuable collection for study by the national and international ichthyological community, only made possible with collaborative expeditions like this one”.
Apart from the specimens and data gained, this was a valuable opportunity for AMRI to forge and strengthen links with international partners. Already some of the connections made during the voyage are being utilised in planning new projects. Additionally, there was important information exchanged regarding sampling techniques and equipment which has immediate application to practices currently used.
The team is now looking forward to the next step – integrating the samples into the AMRI collections so that they are ready and available for research, and reflecting on the discoveries made and the conclusions that result.
Stephen Keable, Elena Kupriyanova, Anna Murray, Mark McGrouther, Sally Reader and Mandy Reid AMRI