Creation year

2008

32 record(s)
 
Type of resources
Topics
Keywords
Contact for the resource
Provided by
Years
From 1 - 10 / 32
  • Categories    

    The barrens-forming sea urchin Centrostephanus rodgersii has undergone poleward range extension to eastern Tasmania. This data compares growth, morphology, reproductive investment and gonad indices between individuals inhabiting barrens ('barrens-maintaining' urchins') with those found on kelp beds ('barrens-forming' urchins) in north eastern Tasmania. The data set is comprised of 3 files. The first (Centrostephanus_biometrics_kelp_vs_barrens_urch.xls) compares biometrics of urchins across 3 sites and 2 habitats in eastern Tasmania. The second (Copy_of_Centrostephanus_annual_jaw_growth_increments.xls) compares annual growth increments of urchins in kelp bed and barren habitat including an additional site in south eastern Tasmania (The Lanterns - Tasman Peninsula) to allow comparison of growth across the newly extended range. The third (Jaw_TD_allometery.xlsx) provides a conversion between the allometry of jaw length and test diameter. Ultimately a generalised growth model for the sea urchin in kelp bed habitat was obtained for eastern Tasmania.

  • Quantitative surveys were undertaken at five sites in the Kent Group, north eastern Tasmania (Murray Pass, Winter Cove, Little Squally Cove,and southern end of Erith Island) by divers using underwater visual census methods to survey the reef habitat. Additional spot dive surveys were undertaken at northern side of East Cove, Garden Cove, Winter Cove, Squally Cove (Deal Island), northern and southern sides of West Cove (Erith Island) and north east and north west coasts of Dover Island. Divers recorded numbers of sea urchins (Centrostephanus rodgersii and Heliocidaris erythrogramma), as well as extent of urchin barrens, size of algal patches, and measured boundaries of macroalgal patches of Macrocystis angustifolia, Phyllospora comosa and Ecklonia radiata-fucoid communities. Spot dives detailed additional qualitative observations of C. rodgersii.

  • Interactions between native and introduced species can help to elucidate the impact of exotic species on the broader community. This work examines utilisation of an introduced gastropod, the New Zealand screwshell (Maoricolpus roseus) by native hermit crabs in eastern Tasmania. Samples of screwshells were collected from Bass Strait, Maria Island, Pirates Bay and Dennes Point using a modified scallop dredge or collected by divers. Site location, date, depth, dredge opening size were recorded, and random sub-samples of shells were measured for length and width, and spire damage was scored. Hermit crabs, if present, were identified to species, sexed and measured.

  • [This data has been superseded by a synthesised global dataset which includes additional ecological data contributed by non-RLS entities (National Reef Monitoring Network). Please visit the corresponding NRMN Collection (IMOS - National Reef Monitoring Network Sub-Facility - Global mobile macroinvertebrate abundance) for the most current version of this data. See "Downloads and Links" section below.] Reef Life Survey is designed to develop and resource a network of skilled recreational divers for rapid and cost-effective assessment of the state of the inshore marine environment at the global scale. The project uses standardised underwater visual census methods employed by trained SCUBA divers to survey fish and invertebrate species and to record habitat type using photo quadrats - this dataset refers to the cryptic fish and invertebrate survey component only.

  • Categories  

    Recent poleward range expansion of the barrens-forming sea urchin Centrostephanus rodgersii (Diadematidae) from mainland Australia to Tasmania, has emphasized the need to understand the population dynamics of this ecologically important species in Tasmania. This work informs potential population dynamics of C. rodgersii in Tasmania by examination of its reproductive ecology. Reproductive periodicity (gonad index and propensity to spawn) was assessed bimonthly for 18 months at 4 sites in eastern Tasmania. Gamete viability was assessed by fertilization and early development trials. Temperature tolerance of Tasmanian C. rodgersii larvae was also assessed to determine whether this species has undergone an adaptive shift to the cooler Tasmanian environment. There was also no evidence for an adaptive shift in reproductive phenology. Reproductive phenology was assessed by determination of peak spawning period (gonad index analysis).

  • The impact of the introduced New Zealand screw shell, Maoricolpus roseus, were assessed using a cageing experiment in SE Tasmania (Bligh Point, D'Entrecasteaux Channel). Three treatments consisted of different substratum type (live, dead and empty shells, and dead shells with 50% occupancy by hermit crabs); which were crossed with 2 levels of screwshell density (high and low). Treatment groups were artificially maintained for 20 months before metabolic chambers were used to quantify the community metabolism of different treatment groups.

  • Interactions between native and introduced species can help to elucidate the impact of exotic species on the broader community. This work examines utilisation of an introduced gastropod, the New Zealand screwshell (Maoricolpus roseus) by native hermit crabs in eastern Tasmania.

  • Behavioural syndromes are important in the context of understanding the evolution of behaviour. This study examines the lifetime development of shy/bold behaviour of dumpling squid (Euprymna tasmanica). The first component examined correlations of shy/bold behaviour across two test contexts - a threat and a feeding test, measured 5 times during the lifetime of the squid. The second component examined developmental plasticity in shy/bold phenotypes with age and sexual maturity.

  • Reef Life Survey is a program that trains and assists a network of skilled and committed recreational divers to cost-effectively assess the state of the inshore marine environment at the continental scale. The program uses standardised underwater visual census methods employed by SCUBA divers to survey fish and invertebrate species and to record macroalgal and coral cover using photo quadrats - this record refers to the website for this program. By standardising techniques and establishing a monitoring system on a nation-wide scale, the program addresses many of the current problems associated with managing the marine environment, including the paucity, patchiness and variable quality of data on the distribution of and trends to marine biodiversity. A central database is managed for the storage, analysis and dissemination of data collected nationally, with a publicly-accessible web-based portal. The website allows information collected on Australia's marine environment to be accessed in a meaningful form by policy-makers and the general public, including recreational groups, scientists and industry. It also has information and resources for particpating divers and those wishing to become involved. The dataset generated by recreational divers will provide a national framework for monitoring the state of the inshore environment and the identification of those threats and locations of greatest conservation concern. This record points to the online resource for Reef Life Survey: http://www.reeflifesurvey.com/

  • We used an in situ manipulative experiment to assess the impacts of the introduced New Zealand screwshell, Maoricolpus roseus, on native soft-sediment community structure and habitat characteristics in SE Tasmania. Impacts were assessed for high and low screwshell density and for the effect of live and dead screwshells, as well as those containing hermit crabs.