Quantitative fish and benthic community surveys of the reefs of Malakula Island, Vanuatu

Full description

Replicate line and belt transects of various sizes were used to estimate densities of several groups of marine organisms around Malakula and associated islands in Vanuatu in 1988.The eight sites chosen for surveys were located at Atchin Island, Crab Bay, Port Sandwich (Lamap), Metai Island (Maskelyne Islands), south east, south and north west of Sakao Island (Maskelyne Islands) and Cook Bay (Maskelyne Islands).Corals, seagrass and other sessile benthic organisms were assessed using 20m line intersect transects. Each site was subdivided into a number of habitats (reef flat, reef crest, shallow slope and deep slope) and five replicate transects were positioned haphazardly within each of these habitats. Reef crests and slopes were surveyed on SCUBA while reef flats were surveyed on snorkel.Permanent transects were established on the south east side of Sakao Island.Invertebrate food and commercial resource species (various Holothurian species, clams (Tridacnidae), Trochus niloticus and Turbo marmoratus (green snail)) were also surveyed. Five (10 in some instances) haphazard 50x5m belt transects were used to survey these species in both the reef crest and reef slope habitats.Selected species of fish were quantified using 50x10m belt transect visual counts. Fish surveyed included , large non-secretive cods and coral trout (Serranidae); snappers or sea perch ( Lutjanidae); sweetlips (Haemulidae); emperors (Lethrinidae); butterflyfishes (Chaetodontidae); large wrasses (Labridae); and parrotfishes (Scaridae).
This component of the survey was designed to provide a detailed picture of marine resources around Malakula Island and associated islands.
This research was a component of a survey of Vanuatu marine resources conducted in March/April 1988 and was funded by the Australian International Development Assistance Bureau.The objectives of the survey were1. to survey and describe the shallow water reef habitats from selected islands of Vanuatu, adequately covering geographical and environmental variation2. to survey and describe the marine habitats around the shores of Malakula, including offshore islands3. to derive a coastal management plan for Malakula and offshore islands which can serve as a basis for Coastal Zone Management plans for the rest of the country4. to train Ni-Vanuatu personnel in marine survey and marine conservation methods

Lineage

Maintenance and Update Frequency: notPlanned

Statement: Statement: Sessile benthos:The line intersect transect (LIT) technique used for assessing sessile benthic organisms was based on the work of Loya 1978 and is described in DeVantier et al. 1985. The length of intersection of all sessile benthic organisms under the transect line was recorded in centimetres, the sum of these intersects giving a measure of percentage cover for the different species of groups of species.The sites were surveyed where possible along a cross-reef profile, which started on the reef flat and ran across the reef crest and down the reef slope. Reefs with deep profiles were surveyed at two depths, one shallow slope area and one deeper slope area. Transect lines on the reef slope were oriented along depth contours parallel to the reef margin.The lifeform categories used in LIT surveys were:MacroalgaeTurf algaeSeagrassSpongeHard coralsDead standing coralNon-scleractinian coralsSoft coralDevantier LM, Barnes DG, Daniel PA and Johnson DB (1985). Studies in the assessment of coral reef ecosystems. 1. Assessment Protocol. Australian Institute of Marine Science, Townsville, Australia.Loya Y (1978) Plotless and transect methods. In: Stoddart DR and Johannes RF (eds) Coral reefs: research methods. UNESCO, Paris, p197-217.Permanent transects were marked by a steel post driven into the substratum, and each transect was marked at approximately two metre intervals with a 10cm masonry nail.Invertebrate resources:An area 2.5m wide was searched either side of a 50m tape and numbers recorded for each species.Fish:Fish surveys were undertaken using the method described in Choat and Ayling (1987). Counts were made in a 5m belt along each side of a 50m tape.Choat JH and Ayling AM (1987) The influence of habitat structure on reef fish communities in north eastern New Zealand. J Exp Mar Biol and Ecol 110:257-272.

Notes

Credit
Benzie, John AH, Dr (Principal Investigator)