Anna Scott
Southern Cross University
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Featured researches published by Anna Scott.
Marine and Freshwater Research | 2013
Anna Scott; Hamish Malcolm; Cristiana Damiano; Darren L Richardson
Understanding the population dynamics of host sea anemones and their symbiotic anemonefish is important given that pressures such as aquarium collecting and bleaching events are adversely impacting their abundance in some Indo–Pacific locations. We examined long-term trends in anemone and anemonefish abundance at four sites within a ‘no-take’ zone at North Solitary Island, Australia, by comparing data from 2008 to surveys done in 1994 and 1995. Species richness was stable, comprising two anemones, Entacmaea quadricolor and Heteractis crispa, and three anemonefishes, Amphiprion akindynos, A. latezonatus, and A. melanopus. In 2008, densities of the most abundant species, E. quadricolor and A. akindynos, were substantially higher than previously recorded, with increases of up to 532% and 133%, respectively. There was a strong relationship between A. akindynos densities and anemone cover, whereas A. latezonatus had higher densities in deeper waters. Densities of this species remained similar over time, although there was a decline at one site. Heteractis crispa and A. melanopus were found in comparatively low numbers. Potential reasons for the overall increase in abundance include: protection from severe swell events, the lack of major bleaching events, the ability of E. quadricolor to reproduce rapidly by asexual reproduction, and the increasing duration of marine park protection.
Invertebrate Reproduction & Development | 2007
Anna Scott; Peter Lynton Harrison
Summary As the sea anemones, Entacmaea quadricolor and Heteractis crispa, provide essential habitat for obligate symbiotic anemonefish, knowledge of their reproductive biology is crucial to their effective management and conservation. This paper provides the first detailed information on the spawning times, behaviour and mode of gamete release for these host anemone species. Anemones were collected from subtropical reefs in the Solitary Islands Marine Park, eastern Australia, and monitored in outdoor flow-through seawater tanks from 2003 to 2005. Sexually reproductive anemones were either male or female, releasing their gametes into the water column for external fertilisation and development. Spawning of both sexes was predominately synchronous and was restricted to a few nights each year during the austral summer and autumn. Males generally began to release gametes prior to females, suggesting that sperm or some associated product may trigger the females to spawn. Sperm were commonly released in milky white streams or clouds, whereas eggs were released singly or in large masses. Reproductive seasonality and synchrony of gamete release suggests that spawning in both species is coordinated by similar responses of individuals to a range of environmental factors such as seawater temperature, photoperiod and lunar cycles. Incorporating knowledge of the sexual reproductive biology of host sea anemones into management and conservation programs could help ensure the viability of their populations and their resident anemonefish.
The Biological Bulletin | 2007
Anna Scott; Peter Lynton Harrison
Little information is available on the sexual reproductive biology of anemones that provide essential habitat for anemonefish. Here we provide the first information on the surface ultrastructural and morphological changes during development of the embryos and planula larvae of Entacmaea quadricolor and Heteractis crispa, using light and scanning electron microscopy. Newly spawned eggs of E. quadricolor and H. crispa averaged 794 μm and 589 μm diameter, respectively, and were covered by many spires of microvilli that were evenly distributed over the egg surface, except for a single bare patch. Eggs of both species contained abundant zooxanthellae when spawned, indicating vertical transmission of symbionts. Fertilization was external, and the resulting embryos displayed superficial cleavage. As development continued, individual blastomeres became readily distinguishable and a round-to-ovoid blastula was formed, which flattened with further divisions. The edges of the blastula thickened, creating a concave-convex dish-shaped gastrula. The outer margins of the gastrula appeared to roll inward, leading to the formation of an oral pore and a ciliated planula larva. Larval motility and directional movement were first observed 36 h after spawning. E. quadricolor larval survival remained high during the first 4 d after spawning, then decreased rapidly.
PLOS ONE | 2016
Piruz Motamedinia; Anna Scott; Kendall Bate; Neda Sadeghi; Guillermo Salazar; Edan Shapiro; Jennifer Ahn; Michael Lipsky; James D. Lin; Greg Hruby; Ketan K. Badani; Daniel P. Petrylak; Mitchell C. Benson; Michael J. Donovan; Wayne D. Comper; James M. McKiernan; Leileata M. Russo
Purpose The analysis of exosome/microvesicle (extracellular vesicles (EVs)) and the RNA packaged within them (exoRNA) has the potential to provide a non-invasive platform to detect and monitor disease related gene expression potentially in lieu of more invasive procedures such as biopsy. However, few studies have tested the diagnostic potential of EV analysis in humans. Experimental Design The ability of EV analysis to accurately reflect prostate tissue mRNA expression was examined by comparing urinary EV TMPRSS2:ERG exoRNA from pre-radical prostatectomy (RP) patients versus corresponding RP tissue in 21 patients. To examine the differential expression of TMPRSS2:ERG across patient groups a random urine sample was taken without prostate massage from a cohort of 207 men including prostate biopsy negative (Bx Neg, n = 39), prostate biopsy positive (Bx Pos, n = 47), post-radical prostatectomy (post-RP, n = 37), un-biopsied healthy age-matched men (No Bx, n = 44), and young male controls (Cont, n = 40). The use of EVs was also examined as a potential platform to non-invasively differentiate Bx Pos versus Bx Neg patients via the detection of known prostate cancer genes TMPRSS2:ERG, BIRC5, ERG, PCA3 and TMPRSS2. Results In this technical pilot study urinary EVs had a sensitivity: 81% (13/16), specificity: 80% (4/5) and an overall accuracy: 81% (17/21) for non-invasive detection of TMPRSS2:ERG versus RP tissue. The rate of TMPRSS2:ERG exoRNA detection was found to increase with age and the expression level correlated with Bx Pos status. Receiver operator characteristic analyses demonstrated that various cancer-related genes could differentiate Bx Pos from Bx Neg patients using exoRNA isolated from urinary EVs: BIRC5 (AUC 0.674 (CI:0.560–0.788), ERG (AUC 0.785 (CI:0.680–0.890), PCA3 (AUC 0.681 (CI:0.567–0.795), TMPRSS2:ERG (AUC 0.744 (CI:0.600–0.888), and TMPRSS2 (AUC 0.637 (CI:0.519–0.754). Conclusion This pilot study suggests that urinary EVs have the potential to be used as a platform to non-invasively differentiate patients with prostate cancer with very good accuracy. Larger studies are needed to confirm the potential for clinical utility.
Marine Biodiversity | 2015
Anna Scott; David Harasti; Thaylon Davis; Stephen D. A. Smith
Host sea anemones provide important habitat for anemonefishes and a range of other commensal organisms, including shrimps and crabs. These anemones typically occur in coral-dominated habitats, although some are also sand-dwelling, such as Stichodactyla haddoni. Climate-driven changes in abundance have been reported for intertidal sea anemones in California (Sagarin et al. 1999), and poleward range extensions have been reported for corals (Baird et al. 2012) and fishes (Figueira and Booth 2009) in southeastern Australia. Documenting species distributions in the latter region is particularly important given that it has been highlighted as a climate change hotspot (Hobday and Lough 2011). The southern distribution of S. haddoni has previously been reported as 28.7°S and 27.5°S on the west and east coasts of Australia, respectively (http://www.ala. org.au). Here, we substantially extend the southern distribution limit with an observation from Nelson Bay (32.71°S, 152.15°E) at 6 m depth on 27 July 2013 (Fig. 1a). While no obligate anemonefishes were found, the shrimp Periclimenes brevicarpalis was noted as a commensal. Furthermore, two individuals of S. haddoni were found in Sydney Harbour (33.50°S, 151. 15°E) at 8 m in August 2007, disappearing between 2008 and 2009. These anemones were found to host
Marine Environmental Research | 2013
Anna Scott; Peter Lynton Harrison; Lyndon O Brooks
Successful reproduction by scleractinian corals is essential for the maintenance of populations that form the foundation of coral reef ecosystems. Laboratory experiments were done to determine the effects of reduced salinity on the fertilization success and larval survival of two coral species, Platygyra daedalea and Acropora millepora, from the Great Barrier Reef, Australia. Fertilization rates of P. daedalea and A. millepora were significantly reduced at 25.8 psu and 33.1 psu, respectively, and completed blocked at 18.4 psu for A. millepora. The estimated larval survival times were similar from 36.8 to 25.8 psu (P. daedalea 291-312 h, A. millepora 207-264 h), whereas the 18.4 psu treatment resulted in estimates of 153 h and 24 h for P. daedalea and A. millepora, respectively. These results demonstrate that reduced salinity is detrimental to the reproductive success of these corals, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and recruitment on reefs.
Proceedings of the Royal Society B: Biological Sciences | 2016
Anna Scott; Danielle L. Dixson
Understanding how bleaching impacts the settlement of symbiotic habitat specialists and whether there is flexibility in settlement choices with regard to habitat quality is essential given our changing climate. We used five anemonefishes (Amphiprion clarkii, Amphiprion latezonatus, Amphiprion ocellaris, Amphiprion percula and Premnas biaculeatus) and three host sea anemones (Entacmaea quadricolor, Heteractis crispa and Heteractis magnifica) in paired-choice flume experiments to determine whether habitat naive juveniles have the olfactory capabilities to distinguish between unbleached and bleached hosts, and how this may affect settlement decisions. All anemonefishes were able to distinguish between bleached and unbleached hosts, and responded only to chemical cues from species-specific host anemones irrespective of health status, indicating a lack of flexibility in host use. While bleached hosts were selected as habitat, this occurred only when unbleached options were unavailable, with the exception of A. latezonatus, which showed strong preferences for H. crispa regardless of health. This study highlights the potential deleterious indirect impacts of declining habitat quality during larval settlement in habitat specialists, which could be important in the field, given that bleaching events are becoming increasingly common.
PLOS ONE | 2014
Anna Scott; Jannah M. Hardefeldt; Karina C. Hall
Anemonefishes and their host sea anemones form an iconic symbiotic association in reef environments, and are highly sought after in the marine aquarium trade. This study examines asexual propagation as a method for culturing a geographically widespread and commonly traded species of host sea anemone, Entacmaea quadricolor. Two experiments were done: the first to establish whether size or colour morph influenced survival after cutting into halves or quarters; and the second to see whether feeding was needed to maximise survival and growth after cutting. Survival rates were high in both experiments, with 89.3 and 93.8% of the anemones cut in half, and 62.5 and 80.4% cut in quarters surviving in experiments 1 and 2, respectively. Anemones that were cut in half were larger in size, and healed and grew quicker than those cut in quarters. However, even though survival was lower when the individuals were cut in quarters, this treatment produced the greatest number of anemones. Feeding increased oral disc diameter growth and reduced wet weight loss, but did not significantly influence pedal disc diameter. Given that the anemones took up to 56 d to form an off-centre mouth, it is highly likely that feeding may have produced greater effect if the experiment was run for longer. This low technology method of propagation could be used to produce individuals throughout the year and the anemones could then be used to supply the aquarium trade or restock depleted habitats, thus supporting biodiversity conservation in coral reef areas.
Marine and Freshwater Research | 2017
Hamish Malcolm; Anna Scott
Species distributions at range edges show complex shifts with climate change. The present study examined anemonefish and host sea anemone abundance at their southern distribution limits on the eastern coast of Australia, to identify factors influencing the geographic responses of the symbiosis. Roaming surveys (30min) were conducted at 21 sites (~30.01–30.95°S) on rocky reefs in a tropical–temperate transition zone. Two species of host anemones (Entacmaea quadricolor and Heteractis crispa) and anemonefishes (Amphiprion akindynos and A. latezonatus) were found, along with Dascyllus trimaculatus. Nearly all anemones and anemonefishes (>99.5%) were associated with vegetated islands and rocky islets, and abundance was influenced by seawater temperature. Greater numbers of H. crispa and A. akindynos than E. quadricolor and A. latezonatus were found; however, most A. akindynos were juveniles. H. crispa provided nursery habitat for both fishes, whereas adult fishes utilised only E. quadricolor. A southern range extension was found for E. quadricolor, and overwintering of A. latezonatus had extended poleward since the mid-1990s. The paucity of islands and rocky islets south of our surveys, and host-usage patterns, could constrain future range extensions. These findings showed climate-driven latitudinal shifts are complex and are likely to be variably constrained for different species.
Marine Biodiversity | 2016
Anna Scott; K. J. W. Rushworth; Steven James Dalton; Stephen D. A. Smith
Anemonefishes are habitat specialists that form obligate symbioses with host sea anemones (Fautin and Allen 1997). Some anemonefishes associate with a range of hosts, whereas others only use one host species. The wideband anemonefish Amphiprion latezonatus is endemic to high-latitude reefs in eastern Australian and, in published sources, has previously only been documented with Heteractis crispa (Fautin and Allen 1997; Ollerton et al. 2007). Here, we establish that A. latezonatus utilizes two additional species, Entacmaea quadricolor and Stichodactyla gigantea. In an unpublished thesis, Richardson (1996) recorded A. latezonatus associating with E. quadricolor in the Solitary Islands Marine Park, New South Wales (NSW), Australia. Sub-adults were found to occupy both H. crispa and E. quadricolor, while breeding pairs were found only in E. quadricolor (Richardson 1996). Our observations confirm the use of these hosts at this location, but also indicate that