Norman Reef Great Adventures Pontoon : 1997 biological survey and summary of damage from Cyclone Justin

Cyclone Justin crossed the coast in the vicinity of Cairns in March 1997. The 50 knot northerly winds that followed the passage of the cyclone led to the break-off of the Great Adventures Norman Reef pontoon. and its subsequent grounding on the reef flat. Sea Research was asked to resurvey the permanent transects that were set up near this pontoon for past monitoring programs as a prelude to repositioning the pontoon. The aim was to establish what damage had occurred in the benthic community due to the pontoon break-off. and to compare this with the effects of the cyclonic waves themselves on the benthic community. A quantitative survey was also made of the pontoon drag scar on the reef flat, and of surrounding reef benthic communities to determine the effects of the pontoon grounding. The survey was carried out in April 1997, almost a month afler the cyclonic episode

Medium-term changes in coral populations of fringing reefs at Cape Tribulation

The aims of this study were to investigate the medium-term effects of sediment run-off caused by the construction of a coastal road through rainforested catchments in late 1984 on the coral communities of the Cape Tribulation fringing reefs. In the absence of any pre-construction baseline we relied on surveys of two similar control locations, north and south of the potential impact location adjacent to the new road catchment, to determine the significance of any changes that occurred. The southern control was adjacent to the long-established portion of the road south of Cape Tribulation and the northern control adjacent to a small undisturbed catchment A preliminary three-year study had suggested that the road construction had no effect of the fringing reefs of this region (Ayling and Ayling 1991). It was also hoped that this longer-term study would shed some light on the nature of on-going changes in the benthic communities of fringing reefs in the Great Barrier Reef region

Crown-of-thorns and coral trout density on three central section reefs : 1983-1989

Sea Research have carried out density surveys of crown of thorns stars, coral trout and chaetodontids on three reefs off Townsville: John Brewer, Lodestone and Davies, on a number of occasions since 1983. Initially, surveys were made on a single back reef slope site, but since November 1984 surveys were also made on front reef sites on each reef. Most sites were surveyed three times over a six year period but the back reef site at Lodestone has been visited four times in !he same period and that on John Brewer five times. In the latest survey of these sites, in June 1989, lethrinids and lutjanids were also counted

Norman Reef environmental monitoring project 1989

The establishment of a tourist destination pontoon serviced by 300 seat international catamarans on Norman Reef to the NE of Cairns prompted the GBRMPA to require an on-going biological monitoring program to be implemented. The aims of the program were to attempt to establish the effect such intensive tourist operations were having on the reef community; specifically on the percentage cover of encrusting organisms, the height of coral colonies and the density of selected fish species. Surveys of corals, other encrusting organisms and fishes were made at 4 sites on Nonnan Reef between March 1987 and June 1988. Sites were: adjacent to the Great Adventures pontoon; in the area of Great Adventures semi-submersible operation; adjacent to the Deep Sea Divers Den main mooring; and at an undisturbed control area. A total of 35 permanent 20m line transects were used to measure the cover of corals and other encrusting organisms. Measures of coral height were also made at each site. Fishes were counted along 5 haphazard 50 x 20m transects at each site

The effect of the Daintree River flood plume on Snapper Island coral reefs

Surveys of fringing reefs were conducted in the Cairns region in early 1995. The reef slope of these reefs supported rich coral communities with mean coral cover of around 80%. The reefs around Snapper Island were particularly rich at this time with 88% cover recorded on the north face of the Island and 88.3% on the south. This small, narrow island is only about two kilometres long from west tip to east lip and lies about 75 kilometres north of Cairns and only five kilometres east of the Daintree River mouth

Where are all the coral trout?

Marine scientists have been looking at methods for counting fishes underwater for some decades and the Marine Park Authority held a number of workshops in the late seventies and early eighties to develop techniques for counting coral trout. They also found that after training using wooden trout models a diver could make a good estimate of the length of any coral trout seen. We used a method that involved two divers searching for trout along 50 metre long by 20 metre wide survey transects so we could get an estimate of the number of coral trout living in a 1000 square metre area of reef. To cover as big a depth range as possible we ran the 50 metre fiberglass surveyors tape that defined each transect down the reef slope from the edge of the reef flat. On most reefs the transect ended in about 15 metres of water but on some shallow reefs the end of the tape was only at 8 or 10 metres depth and on the steep slopes of some outer reefs we reached depths between 20 and 30 metres

The effect of sediment run-off on the coral populations of fringing reefs at Cape Tribulation

The aims of this study were to investigate the effects of sediment run-off caused by the construction in late 1984 of a coastal road through rainforest catchments on the coral communities of the Cape Tribulation fringing reefs. In the absence of any pre-construction baseline we relied on surveys of two similar control locations north and south of the potential impact location adjacent to the new road catchment to determine the significance of any changes that occurred. The southern control was adjacent to the long-established portion of the road south of Cape Tribulation and the northern control adjacent to a small undisturbed catchment

Determination of most accurate survey size and method for visual counting of coral trout (Plectropomus spp.)

Between January and May 1983 coral trout surveys were carried out on 56 reefs in the Cairns and Central Sections of the Great Barrier Reef Marine Park. On 32 of these reefs density estimates were made using two different survey methods. One of these methods was the standard hectare count (150 x 67m) previously developed by GBRMPA in a series of workshops held in the Capricorn Group of reefs. The second method used a much smaller survey area; a transect 50m long and 20m wide (0.1 ha)

Bramble Reef replenishment area: third post-opening survey

The replenishment area on Bramble Reef in the northern Central Section of the Great Barrier Reef Marine Park was closed to fishing by the GBRMPA on the 1st January 1992 to allow stocks of fish species targeted by fishermen to recover. We made a baseline survey of these target fish species and other important reef organisms on Bramble and three adjacent control reefs: John Brewer, Lodestone and Davies, in early September 1991, prior to the closure (Ayling and Ayling 1992a). Surveys of coral trout, crown-ofthorns starfish and butterflyfishes have been made on these control reefs on four occasions since 1983, providing a useful temporal comparison with the baseline results. Similar annual post-closure surveys have been made in the May/June period in 1992 (Ayling and Ayling 1993), 1993 and 1994 (Ayling and Ayling 1994b), and 1995 (Ayling and Ayling 1997). Concern that fishing pressure was being transferred from Bramble to three adjacent reefs following the replenishment closure resulted in the survey being extended to include these reefs, Britomart, Trunk and Little Trunk Reefs, as three new controls in all surveys since 1993. Bramble Reef was re-opened to fishing on 1st July 1995, and following reports of heavy fishing immediately following the opening we were contracted to conduct the first post-opening survey in August 1995, eight weeks after the opening (Ayling and Ayling 1997). Follow up surveys were made in May 1996 and July 1997 (this report), one and two years respectively after the re-opening

Effects of fishing: effects of fishing resumption on a group of previously protected reefs in the Cairns Section

In January 1992 we made baseline surveys of large fishes and other organisms on the five protected MNP B reefs in the Cairns Section that were opened to fishing when the new zoning plan came into effect in April 1992 and on five fished 'control' reefs. The opening reefs were Ribbon #4, Escape, Channel, Wardle and Northeaster, while the appropriate 'controls' were St. Crispins, Ruby, Pell owe, Nathan and Potter. These ten reefs were resurveyed using the same techniques in February 1993, eleven months after the zoning change, to see if we could detect any change on the opened reefs. Surveys were aimed primarily at the large fishes targeted by fishermen, including coral trout, all species of lethrinid (emperors) and all species of lutjanid (snappers). In addition we made surveys of potential prey species (pomacentrids), other important reef organisms (chaetodontids, crown-of-thorns) and encrusting communities (hard coral, soft coral). Underwater visual census techniques were used for the surveys, with 50 x 10 m transects for the large fishes, chaetodontids and crown-of-thorns, and 20 x 2.5 m transects for the small prey fishes. The survey design incorporated three sites on the front of each reef and three on the back, with five replicate transects of each size counted in each site. The surveys on each reef took a day in the field using two observers. The results of the baseline survey have been reported separately (Ayling and Ayling 1992a)