Oral abstracts Oral abstracts The evolution of ASFB – reflections on 35 years of membership Seeing with sound – the behaviour and movements of fish in estuaries 1 2 1 2 01 Martin Gomon1 04 Alistair Becker , Iain M Suthers , Alan K Whitfield 1. Museum Victoria, Melbourne, VIC, Australia 1. University of New South Wales, Sydney, NSW, Australia 2. South African Institute for Aquatic Biodiversity, Grahamstown, South Africa The Australian Society for Fish Biology had as its inception early meetings organised by the ichthyological staff of the Australian Museum and New South Fisheries intended as a mechanism for sharing advances in fish related science and the development of Underwater video techniques have progressed rapidly over the past ten years, and are now used in a diverse range of habitats initiatives leading to the better understanding of the diversity and biology of Australia’s ichthyofauna. Although the enthusiasm from small creeks to the ocean depths. A limitation of underwater video cameras is they rely on high levels of water clarity and and casual nature of this now incorporated body has remained, the various focuses of the Society and its annual conferences have require artificial lighting if used in low light conditions. In systems such as estuaries, turbidity levels often restrict the use of changed over the decades in line with the evolving directions of the institutions and authorities charged with addressing fish conventional video. Acoustic cameras (DIDSON) overcome this problem as they rely on sound to produce near video, flowing studies and management, as well as the transient influences of the many characters that have been the Society’s driving force. footage. Our current research is directed in two areas which firstly include the role of light on key ecological functions such pred- ator-prey interactions in estuaries. Artificial light was found to have a strong influence on trophic interactions around anthropo- Struggling with stochasticity: metaphors, narratives and evidence genic structure. A separate study revealed the distribution and behaviour of estuarine predators and prey were related to diel 1 cycles. Larger fish were more active during the day with some moving into shallow habitats at night. This resulted in increased 02 Leon A Barmuta schooling behaviour of baitfish. Secondly, we are using the DIDSON to gain information on the connectivity of estuaries and 1. University of Tasmania, Hobart, TAS, Australia the coast. Placing the DIDSON at the mouth of estuaries we have been able to enumerate the numbers of fish passing through Rather than bore you with my Greatest Decisive Datasets (I don’t have any) or my Most Influential Policy Document (an oxymo- during tidal phases. We have observed over 4000 fish passing during a single tide, highlighting the potential dynamic nature of ron), I’m taking the opportunity to revisit the Big Idea that excited me as a PhD student in the early 1980s: stochastic, ‘non-equi- estuarine fish populations. librial’ ecosystems. Both lotic and lentic systems seem prime examples, but have we developed appropriate ways of thinking about them – both scientifically and culturally? In reviewing our progress, I will argue that we reach for metaphors rather more Use of a DIDSON acoustic camera improves fishway assessment results and understanding than we’d like to think we do. While this can generate novelty, it can constrain the narratives we spin and the types of evidence 05 of fish migratory behaviour we pursue. I will illustrate by focussing on resilience and regime shifts because they are interesting ideas and have become prom- 1 2 Andrew P Berghuis , David T Roberts , Kris Pitman3 inent themes in our narratives about inland waters. Gathering evidence about these can be problematic. So have the metaphors that generated these ideas in the first place have outlived their usefulness? I have no pat answers, but I hope to reinvigorate our 1. Aquatic Biopassage Services, Bundaberg North, QLD, Australia engagement with big ideas and stochastic systems, and I hope to reinvigorate some of you too. 2. Asset Optimisation, SeqWater, Brisbane, QLD, Australia 3. Pitman Consulting, Landsborough, QLD, Australia Adaptive management: good in theory, hard in practice The assessment of fishways is primarily performed to determine the effectiveness and for identifying factors that limit the passage of fish beyond man-made barriers. Traditional methodologies rely on capturing fish that successfully ascend the fishway 03 1 Sarina Loo compared with the species and size classes of those that are attempting to ascend. This approach relies on the ability to repre- 1. Department of Environment and Primary Industries, East Melbourne, VIC, Australia sentatively sample fish and the assumption that methods such as trapping do not significantly modify their behaviours. Other Adaptive management is a systematic process for improving management by ‘learning by doing’. Actions are adjusted in methodologies utilise transponder or telemetry tagged fish that are detected within or near the fishway. The requirement to response to feedback on the progress towards the desired outcomes or management objectives. Adaptive management is capture and tag a diversity of fish species can negatively impact on a meaningful result for movement through the fishway. practised by implementing and then reviewing policy, or by predicting the outcomes of management activities and then stra- Both methodologies however are often unable to resolve many aspects of fish behaviour. Dual-Frequency Identification Sonar tegically monitoring the actual outcomes to gather information to improve future management. While the theory of adaptive (DIDSON) is a relatively new tool for viewing real time behaviour of fish within and around fishways and can reveal many aspects management has become popular in natural resource management, there are scientific limitations, social issues and institutional that may affect the overall success of a fishway. This study presents the findings of an assessment program using the combined constraints to its practical application. approach of traditional trapping and a DIDSON acoustic camera to assess efficiency of a new fishway design. Results indicate not The Victorian Waterway Management Program has undergone a process of reviewing and updating its state policy and is in only the strategies utilised by fish to successfully move through a fishway but also behavioural responses to external stimuli, diel the process of updating regional planning strategies. The new Victorian Waterway Management Strategy (2013) outlines an patterns of movement and use of the fishway structure as habitat. Use of this technology has the potential to optimise fishway improved approach to the way the program undertakes adaptive management. The strength of the improved approach is the operation and achieve more successful fishway designs by revealing fish behavioural responses that would not otherwise be use of logic models, based on best available knowledge, to define the relationships (known or assumed) between management obtained. outputs, management outcomes and long-term resource condition outcomes. The logic models are used to target monitoring efforts and prioritise research into knowledge gaps or relationships with uncertain evidence. Using underwater video to study the breeding behaviour of Murray cod Despite the improvements to the adaptive management approach, challenges remain. Monitoring costs are prohibitive and 06 (Maccullochella peelii) in the Border Rivers region, New South Wales and Queensland gaining landholder support for long-term monitoring of management outcomes on private land has proven to be difficult. There 1 2 3 3 1 is little scientific knowledge on how much management activity needs to occur to generate specific environmental outcomes. Gavin L Butler , Steven G Brooks , Daniel Smith , Peter K Kind , Stuart J Rowland Additionally, separating the influence on environmental change of extreme events (including droughts, flood and fire) from 1. Fisheries NSW, Grafton, New South Wales, Australia management actions is complex. 2. Qld Department of Agriculture, Fisheries and Forestry, Nambour, Queensland, Australia 3. Qld Department of Agriculture, Fisheries and Forestry, Brisbane, Queensland, Australia Murray cod (Maccullochella peelii) is an icon of the Murray-Darling River System (MDRS). There was a significant decline in the abundance of Murray cod throughout the late 1800s and 1900s, and it is now listed as threatened by the Commonwealth. Whilst, Murray cod stocks have improved throughout parts the MDRS, many aspects of its biology remains poorly understood. The aim of this project is to observe and describe the breeding behaviour of Murray cod in the wild using underwater video techniques. Murray cod were monitored over two breeding seasons (2011 and 2012) in Glen Lyon Dam and the Dumaresq River in the Border Rivers region of NSW and Qld. Aggregation and site selection commenced each year in Glen Lyon Dam in mid-August, with spawning taking place in late August - early September. Nest sites and eggs were also observed in the river over this same peri- od. Murray cod males were observed selecting nesting sites, pairing, spawning and caring for eggs and larvae. From beginning to end the process took upwards of 20+ days. Nest sites were located on hard substrate and mainly underneath rocks in the dam, whilst in the river they were on cobbles in caves along undercut riverbanks. A second round of spawning