A 29-year retrospective analysis of koala rescues in New South Wales, Australia

The koala (Phascolactos cinereus) is currently listed by both the IUCN and the Australian Governments’ Threatened Species Scientific Committee as vulnerable to extinction with a decreasing population trend. This listing can be attributed to climate change and its impact on ecosystems, and anthropomorphic environmental change due to extensive land clearing and habitat fragmentation. These have both been proven to induce stress, which influences the onset of disease. This novel study performed a retrospective analysis whereby records for 12,543 wild, rescued koalas in New South Wales (NSW), Australia were studied in order to determine trends in koala sightings, clinical admissions and injury diagnoses over a period of 29 years (1989-2018). Results indicated that between all three study locations (Port Stephens, Port Macquarie and Lismore), the most common reason koalas were admitted into care was because of disease, the most common disease diagnosed was signs of chlamydia, and the most common outcome for koalas admitted into care was released. At Port Stephens, mature and female koalas were diagnosed with a disease more than any other age or sex, while juvenile and male koalas were released (back into the wild) more than any other age or sex. Additionally, there were fewer koalas with a disease and fewer koalas released in Port Stephens as each year progressed. At Port Macquarie, mature and male koalas were diagnosed with a disease more than any other age or sex, while juvenile and female koalas were released more than any other age or sex. Additionally, there were more koalas with a disease and fewer koalas released in Port Macquarie as each year progressed. At Lismore, adult and female koalas were diagnosed with a disease more than any other age or sex, while joey and male koalas were released more than any other age or sex. Additionally, there were more koalas with a disease and fewer koalas released in Lismore as each year progressed. Determining trends in clinical admissions and diagnosis over such a substantial period of time is an important factor in preventing the continuing decline of koalas throughout Australia, and in particular NSW. It is important to note that there are cultural differences between koala rescue groups in the three study locations (Port Stephens, Port Macquarie and Lismore). These differences may be reflected in the outcomes of koala patients as each group are driven by their own management team. It is essential that any further decline of koala populations is prevented, however this can only be achieved through informed recommendations through research studies such as these. These recommendations should lead to government legislation which can provide stronger protection to koala habitat.

Responses of Dendronephthya australis to predation by Dermatobranchus sp. nudibranchs

The soft coral Dendronephthya australis occurs only in large abundance within the tidal-dominated Port Stephens estuary in eastern Australia. In recent years, substantial declines in the spatial extent of D. australis within Port Stephens has led to calls for the species to be listed as ‘threatened’. The causes for these declines are likely to include a range of anthropogenic impacts, as well as natural effects such as predation by the nudibranch Dermatobranchus sp., which can be abundant in winter and spring. The responses of D. australis to the presence of Dermatobranchus sp. were studied at two sites in Port Stephens, using time-lapse and still photography combined with visual surveys. Dermatobranchus sp. was observed consuming D. australis polyps, and colony inflation and polyp expansion were both reduced when Dermatobranchus sp. was present. Although predation by Dermatobranchus sp. is a natural impact, our observations suggest that interactions with additional anthropogenic stressors may exacerbate its overall impact on the spatial extent and survival of the geographically restricted soft coral D. australis.

First records of three fishes, and southern records of a further four fishes, from New South Wales, Australia

A study of fishes from Port Stephens in New South Wales, Australia has identified first records for three species in New South Wales — Genicanthus watanabei (Yasuda & Tominaga, 1970), Parupeneus indicus (Shaw, 1803), and Plectorhinchus chaetodonoides (Lacépède, 1801) — and southernmost records for a further four species: Cantherhines fronticinctus (Günther, 1866), Coris bulbifrons (Randall & Kuiter, 1982), Mulloidichthys vanicolensis (Valenciennes, 1831), and Paracirrhites forsteri (Schneider, 1801). New sightings were up to 980 km south of previous records, indicating prolonged survival of tropical fish larvae in the East Australian Current.

Distribution and spatial modelling of a soft coral habitat in the Port Stephens–Great Lakes Marine Park: implications for management

Habitat mapping is a useful method for understanding the complex spatial relationships that exist in the marine environment, and is used to evaluate the effectiveness of management strategies, particularly in regards to marine protected areas. This study explored the observed and predicted distribution of an uncommon soft coral species, Dendronephthya australis within the Port Stephens–Great Lakes Marine Park. Dendronephthya australis was mapped by video operated by a SCUBA diver towing a time synchronised GPS. A species distribution model was created to explore the possible occurrence of D. australis outside of the mapped area, using four environmental parameters: bathymetry, slope of seabed, velocity of tidal currents, and distance from estuary mouth. Dendronephthya australis colonies occurred along the southern shoreline in the Port Stephens estuary between Fly Point and Corlette Point, but no colonies were found within sanctuary (no-take) zones within the marine park. The model illustrated limited habitat suitability for D. australis within a larger section of the estuary, suggesting this species has specific environmental requirements survival. Owing to its current threats (anchor damage and fishing line entanglement), implications from these findings will assist future management and protection decisions, particularly in regard to its protection within a marine park.

Developing a habitat classification typology for subtidal habitats in a temperate estuary in New South Wales, Australia

Effective estuarine management depends on adequate data about the ecology, extent and biodiversity of component habitats. However, these data are often scant, as exemplified by the Port Stephens estuary, part of the Port Stephens–Great Lakes Marine Park (NSW, Australia), for which even basic descriptions of habitat types and extent are lacking. Herein we present the results of the first quantitative assessment of subtidal benthic communities within the estuary, involving 130km of towed video transects over an area exceeding 50km2. We identified previously undocumented macroalgae-dominated habitat types and found strong correlations between habitat types and depth. The soft coral Dendronephthya australis habitat is of particular interest because this was found to occur exclusively outside current sanctuary (no take) zones. The habitat map of Port Stephens generated during the study provides the basis for more objective representative planning in future iterations of zoning in the estuarine section of the marine park. The study also suggests that depth may be a useful proxy for estuarine habitat types where specific data are lacking. The classification methodology developed during the study was cost-effective, generated robust data and consequently has potential for wider application in other large estuarine bays.