A large spawning aggregation of giant Australian cuttlefish (Sepia apama) usually occurs on a discrete area of rocky reef adjacent to Pt Lowly in northern Spencer Gulf. This is the only known dense aggregation of spawning cuttlefish in the world and it is highly valued by local residents, the tourism industry, and recreational divers. A cephalopod fishing closure was established in the spawning area in 1998 due to a rapid increase in catches in the area and concerns about the sustainability of the resource.

A series of anecdotal reports, filtered through various media sources, has indicated that this year’s (2011) spawning aggregation appears significantly reduced. There is considerable speculation as to why breeding cuttlefish have “failed to turn up” on the Point Lowly Peninsula spawning grounds, ranging from natural variation in their population dynamics, localised pollution by coastal industrial development, and environmental irregularities. In order to effectively respond to this decline, it is important to determine whether it is an ongoing trend, and if so, what its cause is. Structured cuttlefish surveys, where the data have been made publically available, have not occurred since 2005 (see Steer and Hall, 2005), therefore, it is has not possible to ascertain the magnitude of the annual variation in cuttlefish abundance and biomass. Furthermore, there has not been any structured environmental monitoring within the broader northern Spencer Gulf area to investigate any potential casual links between local environmental conditions and cuttlefish aggregative behaviour. Clearly there is a need to develop an on-going monitoring program that quantifies the abundance and biomass of cuttlefish on the spawning grounds, coupled with a structured environmental monitoring program. This is of particular importance as the spawning grounds are located in close proximity to coastal industry and proposed further infrastructure development.

Australian prawn production at around 22 kilotonnes is valued in excess of $250 million. Clearly, the prawn fishery is an important natural resource for Australia that is also the basis for a significant export industry. In addition, prawn aquaculture is a significant industry in northern Australia and accounts for around 14% of the total volume of Australian prawn production. Infectious myonecrosis is a viral disease that has caused significant disease outbreaks and mortalities in farmed Penaeus vannamei in Brazil and South-East Asia, including Indonesia. While P. vannamei is considered the principal host, experimental infection of P. stylirostris (Pacific blue shrimp) and P. monodon (black tiger shrimp) has been reported. The susceptibility of other shrimp/prawn species is unknown. Information on the susceptibility of prawn species important to Australia, including banana prawns (Fenneropenaeus merguiensis), brown tiger prawns (P. esculentus) is lacking. This project would provide information on the susceptibility of two important species of Australian prawns to exotic IMNV. Such information is important to policy-makers, regulators and primary producers with respect to relevant biosecurity issues at all levels of government.

The shortfin mako, longfin mako and porbeagle sharks have widespread distributions in temperate and tropical waters of all the world’s oceans. Makos are bycatch and by-product species of pelagic longline and gillnet fisheries where they are taken for their meat and high-value fins. They are also highly-prized recreational species in many regions. Makos have low productivity, typical of sharks that do not mature until reaching a large size, producing few young and where individuals are unlikely to reproduce annually. Risk assessments both nationally and in the Atlantic concluded that mako sharks are at the highest risk of all pelagic sharks. These species are listed by the IUCN as Vulnerable globally and Critically Endangered in the Mediterranean. Significant population declines in the Mediterranean Sea and the North Atlantic resulted in these species being listed under Appendix II of the Convention on Migratory Species (CMS) in 2008 and concomitant listing under Australia’s EPBC Act in January 2010. This effectively meant that the target commercial or recreational fishing for these species was prohibited in Australian waters. In May 2010 the National Recreational Mako Shark Fishery - Management Forum identified the need for a study to identify and propose cost effective ways to fill key gaps in the collective knowledge of these species. In July 2010, after considerable debate, a legislative amendment was made to allow for the recreational fishing of mako and porbeagle sharks in Commonwealth areas despite the offence provisions under the EPBC Act. Commercial targeting of these species remains an offence, however, there are exemptions where they are taken as bycatch under accredited management plans. The Federal Environment Minister also directed DEWHA/SEWPaC to work with Fisheries Managers to provide a “more comprehensive information base on mako and porbeagle sharks for the future”. This project is a direct result of these needs.

This project provides research support for 2 PhD students - enabling them to target their studies to issues relevant to the local salmon farming industry in particular the need for research on “Nutrient Production” identified in TSGA research priorities (2011).
Growth of salmon farming in SE Tasmania is currently limited by a feed input cap. This has arisen as a result of concerns that increased nutrients associated with salmon farming may be affecting local water quality. In addition there have been anecdotal reports that changes in macroalgal community structure, and in particular proliferation of nuisance algae species (i.e. Ulva), are related to the expansion of local salmon farming operations.
These PhD projects in combination will specifically evaluate the response of macroalgal communities to changing nutrient and environmental conditions and the implications of this for local and system wide nutrient load management.
Scott Hadley is looking to evaluate the potential to mitigate/ offset nutrient loads using target species deployment and will look at testing scenarios in a model environment to establish spatial and temporal optima for such mitigation strategies.
Whilst Luis Henriquez aims to better define the effects of changing nutrient regimes on local macroalgal communities and to measure differences in nutrient assimilation capacity of key species under differing environmental conditions.
The combined research of these students will provide a much better understanding of the driving factors behind potential "hotspots" in estuarine systems, the likely effects of these on macroalgal communities and the potential for natural and managed nutrient offsets.