River flow is crucial in the life cycle of prawns that support the Northern Prawn Fishery (NPF), as well as iconic tropical species (e.g. mud crab, barramundi, grunter, and threadfin salmon) of importance to commercial, recreational and Indigenous fisheries, and species with high conservation (e.g. sawfish) and cultural value. Substantial interest in developing irrigated agriculture across northern Australia is reviewed in a recent FRDC report (Kenyon et al. 2018). Water extraction to support agriculture will modify natural flow regimes that support estuarine and coastal fisheries. The trade-offs associated with proposed water resource allocation are currently unknown and research is needed to support decision making related to alternative strategies for managing water resources effectively for both agriculture and marine production and biodiversity conservation. Quantifying these trade-offs entails evaluating how altered river flows might affect the fishery and ecological values. Most work to date has focused on the hydrological rather than ecological aspects (and particularly how to quantify aspects such as the minimum water requirements for ecological components) as managers otherwise need to make decisions without sufficient research and given limited timeframes. Although previous and recent projects such as NAWRA have evaluated the qualitative impacts of changes in river flows on ecological assets, there is a need to quantify impacts both for consideration by affected commercial, recreational, indigenous and other sectors, as well as to provide water resource managers with quantitative estimates such as the minimum water requirements to maintain ecosystem structure and functioning. Such analyses are also complicated by the fact that each catchment is different, and hence models and the associated recommendations need to be tailored to be specific to each catchment area, and there is currently no suitable ecosystem model at the appropriate scale and incorporating key relationships.

This project addresses the national research priority "Ensuring that Australian fishing and aquaculture products are sustainable and acknowledged to be so", identified by FRDC as part of their RD&E Plan for the period 2015-2020. Further, this project addresses a research priority listed in FRDC's April 2018 Competitive round call for Expressions of Interest "To gain a better understanding of the spawning aggregations and dynamics of pearl perch". This project also addresses a Fisheries Queensland’s priority identified in their 2017 Monitoring and Research Plan "Research into lifecycle characteristics of pearl perch".

Outputs from a recent stock assessment suggested that the pearl perch stock, which extends southwards into New South Wales waters, is transitional depleted and stock recovery is necessary. This requires an improvement in egg production achievable through the protection of spawning animals. Knowledge of the pearl perch’s spawning dynamics would enable fishery managers to make evidence-based decisions regarding the harvest strategies that increase egg production and, therefore, build the stock biomass. For example, should patterns of pearl perch spawning aggregations be located, like those of the confamilial West Australian dhufish (belonging to the same taxonomic fish family), spatial closures could be employed to protect these aggregations. Similarly, temporal closures are currently used to avoid excessive fishing mortality on coral trout spawning aggregations and similar protection for pearl perch may be appropriate if spawning is timed to coincide with certain biological or seasonal cues. A thorough understanding of these spawning dynamics of the pearl perch is necessary to inform management of the species.

There is a need, therefore, to: (1) collect relevant biological information pertaining to the spawning dynamics of pearl perch, (2) supplement current information with fishery-independent data to better define temporal and spatial spawning patterns over the entire extent of the species’ distribution, and (3) identify areas likely to support spawning aggregations, if any, and to assess the movement to and from these spawning aggregations.

The Australian seafood industry aspires to continue improving its sustainability in many areas, including reducing its carbon emissions and ultimately achieving carbon neutrality. The 2017 National Seafood Industry Leaders called for the industry to strive to become carbon neutral by 2030. There are many aspects to this, such as improving fuel efficiency and evaluating land transport options, but some emissions are inevitable. To offset these emissions, the seafood industry might choose to investigate carbon markets. Investments in blue carbon could also provide added value to the industry, say, through better fish nurseries, or through the social benefits of being seen to proactively nurture the ecosystems that support them. However, the mechanisms to allow the seafood industry to pursue this are poorly developed. Impediments include the paucity of blue carbon opportunities in existing regulatory markets, and uncertainty about the most appropriate financial mechanisms for blue carbon investment.

The industry would benefit from a clear guide that outlines the current (and likely future) opportunities, the risks, a realistic assessment of the benefits, and a set of options for potential investors to pursue. To facilitate this, we will hold a meeting of key seafood industry stakeholders: at this workshop we will inform stakeholders about the current state of knowledge and opportunities, ask the extent to which the industry aspires to be carbon neutral, and whether blue carbon investments are perceived to be relevant. We will identify the major impediments to the industry achieving its desired goals, and plan concrete actions that can be taken to achieve them. These will be compiled into a plan to inform the FRDC on what actions to invest in, and how much investment would be needed.