The motile macroepifauna was examined in stands of Amphibolis antarctica, in mixed stands of Posidonia angustifolia and Posidonia simuosa, and in nearby unvegetated sand at two sites in Holdfast Bay, South Australia. In all, 178 species... more
The motile macroepifauna was examined in stands of Amphibolis antarctica, in mixed stands of Posidonia angustifolia and Posidonia simuosa, and in nearby unvegetated sand at two sites in Holdfast Bay, South Australia. In all, 178 species including 49 species of molluscs and 114 species of crustaceans were recorded in the three habitats. There were significantly more species at both sites, and significantly more individuals at one site, in vegetated than unvegetated substrata. Seagrass biomass was significantly and positively correlated with the number of species and number of individuals at the shallow site, but not at the deeper one. Seagrass biomass appears to be only one of a number of factors determining the structure of the macroepitaunal assemblage. Cluster analyses of samples show that the faunas of each habitat are distinct. Of the 25 most common species, 11 were significantly associated with Amphibolis, eight with Posidonia, and six were associated with vegetated as compared...
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Notolabrus tetricus is a generalist carnivore with a preference for molluscs and crustaceans—small molluscs and amphipods at small wrasse size, and larger molluscs and crabs with increasing size. Dietary overlap between three adjacent 10... more
Notolabrus tetricus is a generalist carnivore with a preference for molluscs and crustaceans—small molluscs and amphipods at small wrasse size, and larger molluscs and crabs with increasing size. Dietary overlap between three adjacent 10 cm size groups is high. No-choice, two-species-choice and multiple-choice field experiments showed that, within the Mollusca, the wrasse prefers chitons and abalone to other gastropods and limpets;crabs and shrimps are high, and echinoderms are low, on the preference list. A comparison of prey consumed with the relative abundance of prey groups shows that the wrasse takes prey more or less in proportion to its abundance, with variation in this pattern attributed to prey defences and predator choice. A long-term study showed that per capita consumption of cryptic abalone increased with increasing abalone density, suggesting a functional response of wrasse to the density of a preferred prey. The wrasse is a diurnal predator with a defined home range t...
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The foraging behaviour, territory size and diet of the scalyfin, Parma victoriae, were studied at three sites in SouthAustralia. Two sites were in Ecklonia habitat on an exposed coast, one of them, Site 1, in a marine reserve atWest I.,... more
The foraging behaviour, territory size and diet of the scalyfin, Parma victoriae, were studied at three sites in SouthAustralia. Two sites were in Ecklonia habitat on an exposed coast, one of them, Site 1, in a marine reserve atWest I., and the other, Site 2, in an intensely fished area at The Bluff, Victor Harbor. The third, Site 3, was sheltered, in a fucoid community in Groper Bay, Flinders I., in the eastern GreatAustralian Bight. The algal food supply was highest at the reserve site (1), and lowest at the sheltered site (3). The scalyfin spent a greater proportion of time foraging, and a lower proportion of time sheltering, at the reserve site (1), than at the Bluff site (2). At Site 3, territories were about seven times larger than at the other two sites, and fish spent a higher proportion of time in defence and aggressive interactions than at the other sites. The diet at all sites was predominantly browsed rhodophytes, but at Site 3 the rhodophytes eaten were almost entirely ...
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ABSTRACT The composition, form and migration of megaripples in a megaripple field in a tidal channel of northern Spencer Gulf, South Australia, were examined over a year. Migration rates of megaripples ranged from about 2 m yr−1 for... more
ABSTRACT The composition, form and migration of megaripples in a megaripple field in a tidal channel of northern Spencer Gulf, South Australia, were examined over a year. Migration rates of megaripples ranged from about 2 m yr−1 for sandwaves 3 m high to about 8 m yr−1 for megaripples 0.4 m high. Migration of the wave form was regular at some sites but irregular at others, where differential migration and erosion gave rise to branching or coalescence of megaripples. Winter migration rates were greater than summer rates at most sites. Estimates of sediment transport rates at two cross-sections of the field suggest only slow and minor net flood transport of sediment of 40–70 m3 yr−1.Sediments are predominantly medium-grained sand well-sorted at the megaripple crests (and elsewhere on fast-moving megaripples) and poorly sorted in troughs between megaripples. The predominantly negative skewness values of the sediments support the conclusion that tidal currents selectively rework the sediments with little input of new material.
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24 NOTICIAS DE GALÁPAGOS No. 62 SUMMARY A local or cottage fishery, principally for the endemic chiton Chiton goodalli, persists in the Galápagos Islands despite declining numbers of chitons. Restaurant con-sumption has also declined in... more
24 NOTICIAS DE GALÁPAGOS No. 62 SUMMARY A local or cottage fishery, principally for the endemic chiton Chiton goodalli, persists in the Galápagos Islands despite declining numbers of chitons. Restaurant con-sumption has also declined in recent years. The size structure ...
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SUMMARY Thirteen sites on southern Yorke Peninsula were surveyed in order to estimate the abundance of the western blue groper, Achoerodus gouldii. Juveniles (<20 cm) were sporadically common at shallow, moderately sheltered sites in... more
SUMMARY Thirteen sites on southern Yorke Peninsula were surveyed in order to estimate the abundance of the western blue groper, Achoerodus gouldii. Juveniles (<20 cm) were sporadically common at shallow, moderately sheltered sites in creviced rocky areas. Sub-adults (20-60 cm) occurred at depths of 2-6 m and their abundance was correlated with that of juveniles, suggesting local recruitment of juveniles
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From 1958-1962, 166 batches of 50 weighted drift bottles were released at four stations in western Bass Strait waters to estimate current strength and transport distance of on-shelf waters; 2120 bottles were recovered from 122 batches.... more
From 1958-1962, 166 batches of 50 weighted drift bottles were released at four stations in western Bass Strait waters to estimate current strength and transport distance of on-shelf waters; 2120 bottles were recovered from 122 batches. Bottles were transported up to 1570 km from release sites at mean speeds of up to 28 cm s-1. The direction of transport showed the presence of seasonally reversing surface waters, which flowed to the west/northwest during summer and to the east/southeast during winter, with some interannual variation in timing of the reversals. Present knowledge of coastal circulation is consistent with drift bottle results. We suggest that larvae of the western population of the rock lobster, Jasus edwardsii, hatching in October in western Bass Strait waters can be transported westerly as far as the eastern Great Australian Bight, and returned to their natal region 9 months later. However, larvae hatching on the west Tasmanian coast may be variously transported offsh...
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Research Interests: Pilot study and Reef Fish
ABSTRACT The abalone Haliotis fulgens deposits fine (non-pigmented) and dark (pigmented) rings in the spire that are useful for aging the shell. A dark ring is deposited annually, and in the first 4–5 years is preceded by one or more fine... more
ABSTRACT The abalone Haliotis fulgens deposits fine (non-pigmented) and dark (pigmented) rings in the spire that are useful for aging the shell. A dark ring is deposited annually, and in the first 4–5 years is preceded by one or more fine rings which are deposited with decreasing frequency over time. External shell erosion causes the loss of about one ring per 32 mm shell length over about 80 mm length. The El Niño events of 1982–3 and 1991–2 caused growth checks in shells of H. fulgens at La Natividad and Bahia Tortugas, Baja California and were used as a time-stamp to validate the rate of deposition of dark rings in the shell. In about 9% of the shells examined more or less dark rings are deposited than expected. In these cases counts of fine rings as well as dark rings can reduce the chance of error.
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Densities of fishes, invertebrates and plants at rocky intertidal and shallow subtidal sites were censused 1-2 days prior to the Jessica oil spill and compared with information obtained for the same sites one month after the spill, both... more
Densities of fishes, invertebrates and plants at rocky intertidal and shallow subtidal sites were censused 1-2 days prior to the Jessica oil spill and compared with information obtained for the same sites one month after the spill, both for sites impacted by oil and unaffected reference sites. While the availability of pre-spill data made this analysis one of the most powerful to date for testing impacts of oil on shoreline environments, no clear changes attributable to oiling could be identified. Discharged oil appeared to cause very little impact in the intertidal and shallow subtidal zones, with such impacts lying within the range of natural spatial and temporal variation at sites investigated. Factors considered to minimize impact in Galápagos included paucity of fully sheltered shores in spill path, moderate wave action, warm temperature, high levels of sunlight, and mixing of bunker oil with diesel.
Research Interests: Petroleum, Invertebrates, MARINE POLLUTION, Population Dynamics, Ecuador, and 18 moreWater Pollution, Multidisciplinary, Oil Spill, Disasters, Flora, Site Investigation, Accidents, Animals, Fauna, Fishes, Rocky Intertidal, Ecosystem, Intertidal Zone, Ships, Plant Development, Geologic Sediments, Shallow Water, and Thallophyta
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ABSTRACT The spatial dispersal and vertical distribution of larvae of Haliotis discus hannai and Tegula spp. were examined in relation to storm events in Miyagi Prefecture, Japan, from 1983 to 1993. Epidemic spawning is induced by... more
ABSTRACT The spatial dispersal and vertical distribution of larvae of Haliotis discus hannai and Tegula spp. were examined in relation to storm events in Miyagi Prefecture, Japan, from 1983 to 1993. Epidemic spawning is induced by typhoons and minor storms. After typhoons, larvae are dispersed in coastal waters up to 3 km from shore to a depth of 30 m and later are advected toward the coast by onshore winds. After minor storms, larvae are locally dispersed close to shore. Larvae of H. discus hannai and Tegula spp. become vertically stratified and settle on the substratum at depths in accordance with the vertical depth range of their larvae. Strong settlements of H. discus hannai of up to 200 m-2 were recorded around headlands, with average survival rates of about 13% per month in the first 2-3 months. The adaptive significance of dispersal over short and long distances is considered.
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Research Interests: Climate Change, Biological Sciences, Environmental Sciences, Range Expansion, Social Communication, and 13 moreCommunity Dynamics, Marine Ecosystems, Sea Urchins, Experimental, Marine Systems, Sea Urchin, Coastal waters, Large Scale, Water Transport, Marine ecosystem, Shallow Water, Macrocystis pyrifera, and Thermal Gradient
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SUMMARY The abundance of the western blue groper (WBG), Achoerodus gouldii, was examined in the nearshore rocky reef areas on the western and northern coasts of Kangaroo Island, which is near the eastern limit of the species'... more
SUMMARY The abundance of the western blue groper (WBG), Achoerodus gouldii, was examined in the nearshore rocky reef areas on the western and northern coasts of Kangaroo Island, which is near the eastern limit of the species' geographic range. Adult males ...
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... Canadian Journal of Fisheries and Aquatic Sciences: ... 2012 Catalog. Mission. To support Canadian researchers and their communities in disseminating their research worldwide through the provision of a world-class, Canadian-based,... more
... Canadian Journal of Fisheries and Aquatic Sciences: ... 2012 Catalog. Mission. To support Canadian researchers and their communities in disseminating their research worldwide through the provision of a world-class, Canadian-based, not-for-profit, advanced scientific and ...
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ABSTRACT The long-term movement of the abalone Haliotis laevigata was measured at three sites in Waterloo Bay, South Australia, characterized by differing amounts of available crevice space. Movement was negligible at a site where... more
ABSTRACT The long-term movement of the abalone Haliotis laevigata was measured at three sites in Waterloo Bay, South Australia, characterized by differing amounts of available crevice space. Movement was negligible at a site where crevices were abundant, but extensive at a site without crevice space. At a site of limited available crevice space, the amount of movement increased as available crevice space decreased. In addition, the extent of movement was size dependent and movement was oriented in the direction of the approaching swell.Current experimental designs for measuring natural mortality of abalone depend heavily on assumptions about their movement. An understanding of this behaviour is thus a prerequisite for designing experiments to measure the mortality rates of abalone or other sedentary animals.The natural mortality rate at one site was estimated to be 0.59 (s.e.m. = 0.02, i.e. survival = 56% per year) and the disappearance rate (natural mortality and emigration) was independent of sex.
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The growth and survival of the blue abalone Haliotis fulgens was followed for 11 months in barrel culture in the sea at Cedros Island, Baja California. The mean growth rate was 49.4 μm day−1 for individuals whose initial mean lengths were... more
The growth and survival of the blue abalone Haliotis fulgens was followed for 11 months in barrel culture in the sea at Cedros Island, Baja California. The mean growth rate was 49.4 μm day−1 for individuals whose initial mean lengths were 12–15 mm at the ages of 6–7.6 months. The abalone were fed Macrocystis pyrifera and Eisenia arborea and other