- Perth, Western Australia, Australia
Mike van Keulen
Murdoch University, School of Veterinary and Life Sciences, Faculty Member
Abstract. As part of the CSIRO Wealth from Oceans Ningaloo Collaborative Cluster programme currently underway in Western Australia, this study aims to examine lagoonal habitats and biodiversity within Ningaloo Reef. Key habitat types were... more
Abstract. As part of the CSIRO Wealth from Oceans Ningaloo Collaborative Cluster programme currently underway in Western Australia, this study aims to examine lagoonal habitats and biodiversity within Ningaloo Reef. Key habitat types were identified using information from hyperspectral remote sensing and were used to develop a stratified sampling approach. Two focal areas were selected, based on sanctuary zones within Ningaloo Marine Park: Osprey Bay and Coral Bay in the north and south respectively.
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Page 1. BULLETIN OF MARINE SCIENCE, 71(3): 12571267, 2002 1257 COMPARISON OF WATER VELOCITY PROFILES THROUGH MORPHOLOGICALLY DISSIMILAR SEAGRASSES MEASURED WITH A SIMPLE AND INEXPENSIVE CURRENT METER ...
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Herbivore grazing is a well-documented cause of habitat decline in terrestrial systems, but marine examples from seagrass meadows are rare. Here we present evidence that isolated urchin grazing events have caused further localized losses... more
Herbivore grazing is a well-documented cause of habitat decline in terrestrial systems, but marine examples from seagrass meadows are rare. Here we present evidence that isolated urchin grazing events have caused further localized losses to seagrass meadows already degraded by eutrophication or other anthropogenic disturbances. By 1992 a substantial scar in Posidonia meadows at Luscombe Bay in Cockburn Sound, Western Australia, had been caused by grazing urchins. When seagrass transplants were placed at the site more than a decade later most were grazed and did not survive. GIS analyses on imagery from 1985 to 2004 indicated that rapid seagrass meadow decline coincided with the presence of an unusually large aggregation of the grazing urchin Heliocidaris erythrogramma. Evidence of some seagrass recovery after 1993 was also apparent after the manual removal of the urchins in late 1992. Restoration efforts in seagrass meadows should consider the potential for grazing damage, as is com...
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Recent findings have shown that photosynthesis in the skin of the seed of Posidonia oceanica enhances seedling growth. The seagrass genus Posidoniais found only in two distant parts of the world, the Mediterranean Sea and southern... more
Recent findings have shown that photosynthesis in the skin of the seed of Posidonia oceanica enhances seedling growth. The seagrass genus Posidoniais found only in two distant parts of the world, the Mediterranean Sea and southern Australia. This fact led us to question whether the acquisition of this novel mechanism in the evolution of this seagrass was a preadaptation prior to geological isolation of the Mediterranean from Tethys Sea in the Eocene. Photosynthetic activity in seeds of Australian species of Posidoniais still unknown. This study shows oxygen production and respiration rates, and maximum PSII photochemical efficiency (Fv : Fm) in seeds of two Australian Posidonia species (P. australis and P. sinuosa), and compares these with previous results for P. oceanica. Results showed relatively high oxygen production and respiratory rates in all three species but with significant differences among them, suggesting the existence of an adaptive mechanism to compensate for the rela...
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Dietary characteristics and the degree of dietary partitioning by five species of sympatric stingray were assessed using stomach content and sediment analyses within a coral reef lagoon at Ningaloo Reef, Western Australia (the cowtail... more
Dietary characteristics and the degree of dietary partitioning by five species of sympatric stingray were assessed using stomach content and sediment analyses within a coral reef lagoon at Ningaloo Reef, Western Australia (the cowtail Pastinachus atrus, blue-spotted fantail Taeniura lymma, blue-spotted mask Neotrygon kuhlii , porcupine Urogymnus asperrimus rays and the reticulate whipray Himantura uarnak). A total of 2804 items were recovered from the stomachs of 170 rays and 3215 individual taxa from the environment, which were used in selectivity analyses. Twenty-four prey taxa were identified from stomach contents and pooled into 10 taxonomic categories for analysis, of which annelids, prawns, brachyurans and bivalves were the most abundant, together accounting for 96% of the diet. Himantura uarnak had the greatest interspecific dissimilarity in diet, consum-ing a larger proportion of crustaceans, notably penaeids (41% of total diet) than the other four species of rays, all of wh...
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For some species certain biological and ecological data, such as diet, age and growth estimates can only be obtained through lethal sampling of study animals. Traditionally, commercial fishermen have provided samples of rays caught in... more
For some species certain biological and ecological data, such as diet, age and growth estimates can only be obtained through lethal sampling of study animals. Traditionally, commercial fishermen have provided samples of rays caught in nets for use by biologists; however, by-catch exclusion devices now prevent medium and larger-bodied rays (>100 cm disc width) from being collected in trawl nets. This means that other methods must be used for lethal sampling. We obtained a large suite of biological and ecological data from 170 wild-caught stingrays collected from Ningaloo Reef, Western Australia over two years. Our sampling program was designed to minimize or eradicate any pain and suffering to the animals, while ensuring the safety of researchers undertaking the sampling process. Small rays (< 100 cm disc width; WD) were caught in beach seines and euthanized immediately by destruction of the brain and severance of the spinal cord with a reinforced, serrated steel knife. Larger ...
This paper will briefly examine the current status of seagrass restoration in Australia and, after some definitions have been dispensed with, describe where most of the efforts have been located and their relative 'success'.... more
This paper will briefly examine the current status of seagrass restoration in Australia and, after some definitions have been dispensed with, describe where most of the efforts have been located and their relative 'success'. Attention is placed more upon the lessons regarding transplant failure we have learned from past studies, as opposed to an in-depth study of each project. In addition, factors contributing to variable success rates with different techniques (seedlings, sprigs and cores) will be highlighted using examples from Western Australia – where many transplant efforts have been located. Examples will then be given of the most recent rehabilitation studies in Western Australia, focusing on mechanical transplanter development, refinement and operation. Concluding comments are then made regarding suggestions to maximise success in future transplantation programmes along with a basic list of requirements.
ABSTRACT The reproductive biology of the sand dollar Peronella lesueuri was studied between 2009 and 2011 in Cockburn Sound, a large coastal embayment in south-western Australia. Individuals of P. lesueuri did not display sexual... more
ABSTRACT The reproductive biology of the sand dollar Peronella lesueuri was studied between 2009 and 2011 in Cockburn Sound, a large coastal embayment in south-western Australia. Individuals of P. lesueuri did not display sexual size-dimorphism, and the population was found to have a sex ratio of 1:1. Maturity occurred over the range of 80-115 mm with all sand dollars larger than 115 mm having distinct gonads. Monthly histological analysis of gonads and changes in oocyte proportions over time indicated that P. lesueuri has an annual reproductive cycle; gametogenesis occurs in spring and spawning in summer. Differences in the rate of gametogenesis between 2009/2010 and 2010/2011 may have been influenced by higher temperatures experienced in 2010/2011. P. lesueuri have large ova (mean = 210 μm), which suggests the species has lecithotrophic larval development.
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Seagrass meadows are valuable ecosystem service providers that are now being lost globally at an unprecedented rate, with water quality and other localised stressors putting their future viability in doubt. It is therefore critical that... more
Seagrass meadows are valuable ecosystem service providers that are now being lost globally at an unprecedented rate, with water quality and other localised stressors putting their future viability in doubt. It is therefore critical that we learn more about the interactions between seagrass meadows and future environmental change in the anthropocene. This needs to be with particular reference to the consequences of poor water quality on ecosystem resilience and the effects of change on trophic interactions within the food web. Understanding and predicting the response of seagrass meadows to future environmental change requires an understanding of the natural long-term drivers of change and how these are currently influenced by anthropogenic stress. Conservation management of coastal and marine ecosystems now and in the future requires increased knowledge of how seagrass meadows respond to environmental change, and how they can be managed to be resilient to these changes. Finding solutions to such issues also requires recognising people as part of the social–ecological system. This special issue aims to further enhance this knowledge by bringing together global expertise across this field. The special issues considers issues such as ecosystem service delivery of seagrass meadows, the drivers of long-term seagrass change and the socio-economic consequences of environmental change to seagrass.
Donor meadow recovery is important in deciding whether removal of material from natural seagrass meadows is a sustainable activity. Thus an investigation into meadow regrowth was undertaken as part of a large-scale seagrass rehabilitation... more
Donor meadow recovery is important in deciding whether removal of material from natural seagrass meadows is a sustainable activity. Thus an investigation into meadow regrowth was undertaken as part of a large-scale seagrass rehabilitation effort in Cockburn Sound, ...
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Diverse and abundant bacterial populations play important functional roles in the multi-partite association of the coral holobiont. The specificity of coral-associated assemblages remains unclear, and little is known about the inheritance... more
Diverse and abundant bacterial populations play important functional roles in the multi-partite association of the coral holobiont. The specificity of coral-associated assemblages remains unclear, and little is known about the inheritance of specific bacteria from the parent colony to their offspring. This study investigated if broadcast spawning and brooding corals release specific and potentially beneficial bacteria with their offspring to secure maintenance across generations. Two coral species, Acropora tenuis and Pocillopora damicornis, were maintained in 0.2 μm filtered seawater during the release of their gametes and planulae, respectively. Water samples, excluding gametes and planulae, were subsequently collected, and bacterial diversity was assessed through a pyrosequencing approach amplifying a 470-bp region of the 16S rRNA gene including the variable regions 1-3. Compared to the high bacterial diversity harboured by corals, only a few taxa of bacteria were released by adult corals. Both A. tenuis and P. damicornis released similar bacteria, and the genera Alteromonas and Roseobacter were abundant in large proportions in the seawater of both species after reproduction. This study suggests that adult corals may release bacteria with their offspring to benefit the fitness in early coral life stages.
Research Interests: Microbiology, Microbial Ecology, Ecology, Biodiversity, Phylogeny, and 5 moreGerm Cells, Anthozoa, Animals, Bacteria, and Seawater
ABSTRACT Rates and direction of movement in the sand dollar Peronella lesueuri were measured in summer and winter in Cockburn Sound, a large coastal embayment in south-western Australia. P. lesueuri was found to have a diurnal activity... more
ABSTRACT Rates and direction of movement in the sand dollar Peronella lesueuri were measured in summer and winter in Cockburn Sound, a large coastal embayment in south-western Australia. P. lesueuri was found to have a diurnal activity pattern throughout the year and had a greater movement rate in the summer (mean of 5.3 cm h−1, day; 3.9 cm h−1, night) than in the winter (mean of 2.7 cm h−1, day; 2.0 cm h−1, night). Seasonal change in temperature and physiological requirements by the sand dollar are the most likely reason for the seasonal differences. Reasons for diurnal variation were not clear. Direction of movement was found to be random at both times of the year. Based on these movement rates, one sand dollar can bioturbate an approximate area of 0.1 m2 day−1 and 36.4 m2 year−1. At a conservative density estimate of 0.5 sand dollars per m2 it takes approximately 20 days for the sand dollars to rework the entire area of the sediments in the habitats they occupy.
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ABSTRACT Coastal developments of all scales impact on seagrass meadows. Mitigation for loss of seagrass ecosystems is increasingly being required by regulatory agencies to compensate for coastal developments and while many attempts have... more
ABSTRACT Coastal developments of all scales impact on seagrass meadows. Mitigation for loss of seagrass ecosystems is increasingly being required by regulatory agencies to compensate for coastal developments and while many attempts have been made to transplant seagrasses, there are concerns about the long-term viability of these efforts, as well as the sustainability of harvesting natural seagrass material for transplantation. The present pilot study demonstrates a novel way of maximising establishment of Amphibolis antarctica seedlings. Seedlings were planted and tethered using an innovative spiral peg, in a bare sand area adjacent to a mature Amphibolis meadow in Shoalwater Bay, Western Australia. Survival and growth were monitored over two years. After two years, 29.4% of seedlings survived into well-established mature plants. By enhancing establishment success of seedlings it is anticipated that more rapid and sustainable rehabilitation of Amphibolis seedlings will be possible.
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Globally, many coral reefs are degraded and demonstrate reduced coral cover and increased macroalgal abundance. While negative correlations between macroalgae and coral recruitment have commonly been documented, the mechanisms by which... more
Globally, many coral reefs are degraded and demonstrate reduced coral cover and increased macroalgal abundance. While negative correlations between macroalgae and coral recruitment have commonly been documented, the mechanisms by which macroalgae affects recruitment have received little attention. Here we examined the effect of macroalgae on larval settlement and the growth and survival of coral recruits, in a field experiment over nine months. Exclusion treatments were used to manipulate herbivory and macroalgal biomass, while settlement tiles measured coral settlement and survival. After nine months the volume of macroalgae was up to 40 times greater in the caged treatments than in controls and the settlement of coral larvae on the undersides of tiles within caged plots was 93% lower than in the uncaged treatments. The growth and survival of coral recruits was also severely reduced in the presence of macroalgae: survival was 79% lower in caged treatments and corals were up to 58% ...