IMAS Metadata Catalogue
2008
Type of resources
Topics
Keywords
Contact for the resource
Provided by
Years
-
Black Jew fish in the Northern Territory and Banded Morwong and Bastard Trumpeter in Tasmania have been tagged with acoustic tags and tracked using VR2's (presence/absence data) and VRAP (triangulated positional data) (Tas fish only).
-
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).
-
Underwater visual census surveys were conducted at 15 sites in eastern Tasmania to quantify the abundance of the sea urchin Heliocidaris erythrogramma and several putative predators.
-
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.
-
The predators of Centrostephanus rodgersii, were identified using remote video monitoring. Experiments were performed in two eastern Tasmanian regions, the Maria Island Marine Reserve (MIMR, 42° 35.26'S, 148° 3.03'E) and the Crayfish Point Research Reserve (CPRR, 42° 57.37'S, 147° 21.30'E). The impact of fishing on these predators, and ultimately on C. rodgersii, was examined by comparing survival of C. rodgersii on reefs inside no-take Marine Protected Areas (MPAs) (high predator biomass) relative to fished reefs (low predator biomass). The size-specific nature of predation interactions was examined in context of size-selective fishing pressures within the sea urchin's extended range.
-
Sampling of commercial mid-water trawl catches for small pelagics from waters adjacent to Tasmania have yielded an extensive biological dataset in space and time. As a minimum, size composition information is available from most commerical shots undertaken between 2002 and 2006, referenced with operational information (location, depth and catch weight). Subsamples of the key small pelagics, redbait, jack mackerel and blue mackerel, were examined for size, sex, gonad weight and stage and otoliths have been retained for age determination. Further data has been collected since the initial investigation.
-
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.
-
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.
-
Growth models were constructed for two sea urchin populations over a two-year period using a tag-recapture study in the Mercury Passage, Tasmania. Sea urchins were tagged using tetracycline and calcein and growth models constructed using measurements taken from sea urchin jaws.
-
Impacts of New Zealand screwshells (Maoricolpus roseus) on native scallop distribution and behaviour
The impact of the introduction of the New Zealand screwshell (Maoricolpus roseus) on scallop distribution and behaviour in the D'Entrecasteaux Channel, SE Tasmania was investigated. The impact of both live and dead and empty M. roseus shells on the distribution of two sympatric scallop species, queen scallop (Equichlamys bifrons) and doughboy scallop (Chlamys asperrimus) was quantified at large spatial scales. Also quantified was the impact of M. roseus on the distribution and behaviour of the commercial scallop (Pecten fumatus), at both large and small spatial scales.