| Summary: | Maintenance and Update Frequency: notPlanned Statement: The survey was conducted during voyage 11/94 of the CSIRO Oceanographic Research Vessel Franklin from Port Lincoln, South Australia to Fremantle, Western Australia between 6 and 19 December 1994. The course of the voyage followed continental shelf waters across the Great Australian Bight, then penetrated oceanic waters for several days before returning to shelf waters for the remainder of the journey north (see thumbnail). All seabirds within a 150 m radius forward of the bridge were recorded during a series of 10 minute counts, using the protocols of Tasker et al. (1984). Three continuous ten-minute counts were conducted during each hour of daylight that the vessel was moving, usually at 12 knots (22 km/h). The observer was 10 m above sea level ensuring a view 12 km to the horizon on clear days. Species not readily identified by the observer using binoculars were confirmed either by a second observer or by sketches and notes made at the time of observation. At the start and end of each 10-minute transect, records were made of position, sea surface temperature and salinity, water depth, current speed and direction, ambient temperature, wind speed and direction, sea conditions and visibility. Seabirds observed outside the sampling occasions were also recorded and the positions of any feeding flocks noted, together with any associations with marine mammals or fish. Mean abundances were calculated for each seabird species using pooled observations for each series of three ten-minute counts from the formula: Abundance = Number of birds / (S × T × 300) where S is the speed of the vessel (km/h), T is the time elapsed during the count and 300 is the width of the transect surveyed (m). Mean abundances were compared with each other using Student t-tests. The cruise track was divided into 29 blocks, each 1° square, that contained at least six 10-minute counts (see thumbnail). The mean abundance along the cruise track for each species was then calculated using all ...
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