Southern Bluefin Tuna: Changing The Trajectory
Egg distribution, reproductive parameters and spawning biomass of Blue Mackerel, Australian Sardine and Tailor off the East Coast during late winter and early spring
Knowledge of the winter/spring spawning patterns of Blue Mackerel and Australian Sardine is needed to underpin future assessment of these stocks and to underpin the ecologically sustainable development of pelagic fish resources off the East Coast of Australia.
Recent and robust estimates the population size of Blue Mackerel and Australian Sardine off the East Coast are needed to address community concerns regarding the potential ecological impacts of large scale fishing for small pelagic fishes off the East Coast.
Information on the egg distribution, reproductive parameters and spawning biomass of Tailor is needed to inform future management of this iconic recreational fishing species.
Final report
Beyond GVP: The value of inshore commercial fisheries to fishers and consumers in regional communities on Queensland’s east coast
There are multiple threats to ongoing access/operation of commercial inshore fisheries (finfish and crab) along Queensland’s east coast. These include port developments and expansions, coastal development, public perception (which influences management) and competition between fishing sectors (which also influences management). These threats to access could adversely affect not only commercial fishers themselves, but also secondary industries as well as the availability of seafood to local communities. It is now well documented that consumers prefer local seafood products, and are willing to pay more for seafood labelled ‘local’ (Tobin et al. 2010; Calogeras et al. 2011).
It could be assumed that reducing these threats and ensuring ongoing operation of commercial fisheries and local seafood supply is desirable, for many social and economic reasons. Yet there is little information about the value inshore commercial fisheries and fishing businesses provide to communities (aside from the much used GVP, which has long been recognised as a nonsensical measure of value (e.g. Edwards 1991, McPhee & Hundloe 2004)), or the relative value of local seafood compared to non-local seafood for consumers.
Without knowing the real economic value of commercial fisheries and local seafood for regional communities, decisions regarding management of, and access to, resources are likely to be ill informed. Real value information can be used to ensure appropriate access of fishers and consumers to fisheries resources, better assess the economic impacts of other coastal activities that negatively affect fishing, or better inform reallocation processes where necessary.
Final report
Summer spawning patterns and preliminary Daily Egg Production Method survey of Jack Mackerel and Sardine off the East Coast
Knowledge of the summer spawning patterns of Jack Mackerel and Australian Sardine is needed to underpin future assessment of these stocks and to underpin the ecologically sustainable development of pelagic fish resources off the East Coast of Australia.
Methods for estimating the population size of Jack Mackerel and Australian Sardine need be established to address community concerns regarding the potential ecological and social impacts of large scale fishing for small pelagic fishes off the East Coast.
Final report
This study was undertaken collaboratively by fisheries scientists from the South Australian Research and Development Institute (SARDI) and the University of Tasmania. It was the first dedicated application of the Daily Egg Production Method (DEPM) to Jack Mackerel, Trachurus declivis. It successfully collected large numbers of samples of eggs and adults concurrently from the key spawning area off eastern Australia during what has been previously identified as the main spawning period. The study established an effective method for sampling adult Jack Mackerel and provides the first estimates for this species of the adult reproductive parameters required for application of the DEPM. The spawning biomass of Jack Mackerel off eastern Australia during January 2014 was estimated to be approximately 157,805 t (95% CI = 59,570 358,731). Most of the estimates of spawning biomass obtained in sensitivity analyses were between approximately 95,000 t and 215,000 t. Plausible values for only two parameters provide estimates of spawning biomass that were outside that range; both of these parameters were estimated with a high degree of confidence in the present study.
This was also the first study to investigate the spawning habitat of Australian Sardine Sardinops sagax off eastern Australia during summer. It showed that during January 2014 spawning occurred between northern Tasmania and southern Victoria. The spawning biomass at this location during this period was approximately 10,962 t. This estimate should be treated with caution as adult samples were not collected during the study. It also is important to note that this not an estimate of the total adult biomass of Australian Sardine off eastern Australia. It is only an estimate of the portion of the population that was spawning in this southern part of the range during that period. The main spawning area of Australian Sardine off eastern Australia occurs off southern Queensland and northern NSW during late winter and early spring.
Keywords: Jack Mackerel, Trachurus declivis, Australian Sardine, Sardinops sagax, Daily Egg Production Method, Spawning Biomass, Small Pelagic Fishery, eastern Australia, Tasmania, Bass Strait.
Life history specific habitat utilisation of tropical fisheries species
The health and longevity of fisheries depend on access critical habitats appropriate to each particular life-history stage. While many key fisheries habitats are under threat from rapidly increasing coastal development, management of those habitats is severely hampered by very poor understanding of these life history-stage habitat requirements. This not only prevents effective management of critical fisheries resources but hampers the ability to direct development to enhance, rather than degrade fisheries value. At the moment many management and offsets actions are unsatisfactory to all users because they are based on incomplete understanding of fish-habitat relationships. This means actions and offsets rarely product tangible gains in ecosystem health or biodiversity, frustrating fishers, environmentalists, developers and governments alike. Not only can carefully designed developments provide new areas of critical habitat to replace habitats damaged in the past, but the opportunity exists for directing mandatory offsets from new coastal developments towards beneficial fisheries outcomes. This would provide the basis for greatly improved management of coastal fisheries habitats and would help to direct effective offset strategies, assist in directing fisheries friendly infrastructure design, and allow the development of metrics appropriate to the definitive measurement of specific fisheries outcomes from particular offset actions. Consequently, improved understanding of stage-specific habitat requirements of fisheries species is central to both the long-term health of fish stocks and fisheries productivity, and the effective management of coastal development to enhance fisheries values.