Improving confidence in the management of the blue swimmer crab (Portunus armatus) in Shark Bay PART III: Proceedings of the Third National Workshop on Blue Swimmer Crab Portunus armatus Western Australian Fisheries and Marine Research Laboratories, Hillarys, Perth, 3 – 4 June 2015. FRDC Project No. 2012/15

The ‘Third National Workshop on Blue Swimmer Crab’ was organised and held at Department of Fisheries (Western Australia) in Hillarys (3-4 June, 2015), almost 15 years after the second workshop in 1997. The workshop brought together fisheries scientists, managers, university researchers, consultants, industry stakeholders and fishers from across Queensland, New South Wales, South Australia, Tasmania and Western Australia and addressed six broad themed sessions; • State overview of blue swimmer crab commercial fisheries • Monitoring, stock assessment and harvest strategy • Environmental drivers and climate change • Blue swimmer crabs….from the sea to the plate • Recreational fishing and surveys • Management, policy and industry perspective

Understanding recruitment variation (including the collapse) of Ballot’s saucer scallop stocks in Western Australia and assessing the feasibility of assisted recovery measures for improved management in a changing environment. FRDC Project No. 2015/026

This study examined possible contributing environmental factors to the recruitment variability of the Ballot’s saucer scallop Ylistrum balloti across the main stocks in Western Australia. The project was undertaken to explain the variation observed between years and between regions as well elucidating the potential cause of a major decline in scallop stocks following an extreme marine heatwave, with these findings intended to improve future management advice

Assessment of blue swimmer crab recruitment and breeding stock levels in the Peel-Harvey Estuary and status of the Mandurah to Bunbury Developing Crab Fishery

Two projects were funded to investigate iconic blue swimmer crab stocks in the Peel-Harvey Estuary and Mandurah to Bunbury Developing Crab Fishery. One was a four year project (2007 – 2011) to undertake the following: i) determine recruitment and spawning stock levels of the crab population in the Peel-Harvey Estuary and whether the status of stocks has changed considerably in the past decade, ii) establish a commercial monitoring program to assess the length frequency and sex ratio of crabs captured by commercial fishers, and iii) develop a commercial monitoring program in the Mandurah to Bunbury Developing Crab Fishery and South West Trawl Managed Fishery. A fishery-independent study was conducted at 15 sites throughout the estuary per month between December 2007 and December 2011. Sites chosen were identical to those surveyed between 1995 and 1998, to allow historical comparisons. Additional trap sites were sampled outside the Peel-Harvey Estuary monthly from August 2008 to December 2011 to understand crab abundance, composition and movement between estuarine and oceanic waters. A second project was a 12-month recreational survey in the Peel-Harvey Estuary between November 2007 and October 2008 to provide an estimate of recreational catch and effort

Stock Assessment for the Shark Bay Scallop Fishery

The Shark Bay scallop fishery is based on a single species Amusium balloti and is the most valuable scallop fishery (AUD 10-57 million) in Western Australia. This species is short-lived, has fast growth and highly variable recruitment which is primarily environmentally driven. The scallop fishery consists of two classes of licences, A and B. There are fourteen Licensed Fishing Boats with A Class licences that target scallops and account for approximately 70% of the catch. There are twenty-seven Class B licences, which primarily fish for prawns (in the Shark Bay Prawn Managed Fishery) with scallops a secondary target species. Restructuring and gear amalgamation within the Class B fleet has currently reduced the number of boats actively fishing to 1

Minimising gear conflict and resource sharing issues in the Shark Bay trawl fisheries and promotion of scallop recruitment

Objectives 1. To determine size specific recapture mortality rates of Amusium balloti as a result of repeated capture and release experiments and gear impacts on newly recruited (juvenile) scallops. 2. To determine the impacts of various scallop mesh sizes for the capture of the target size of Amusium balloti and its impact on damage to and retention of prawns. 3. To investigate if small-scale spatial closures assist recruitment of Amusium balloti by reducing gear impacts and capture mortality but without affecting overall prawn catches. 4. To examine whether existing hydrodynamic models can guide the selection of spatial closures and to investigate the larval transport mechanisms of both prawn and scallop larvae in Shark Bay

Improving confidence in the management of the blue swimmer crab (Portunus armatus) in Shark Bay. Part I : Rebuilding of the Shark Bay Crab Fishery. FRDC project no. 2012/15

This, and the accompanying Part II report, summarise the results of the research activities undertaken on the blue swimmer crab stock in Shark Bay by the Department of Fisheries, Western Australia, which were done in collaboration with commercial fishers, fishery managers and economic analysts between 2012 and 2016

Mate choise in homarid lobsters, will they recognise their own species?

As European and American lobsters are so similar that it is difficult to spot the difference, and as they have so many similarities in behaviour and life history, this study was initiated to test if they could make distinctions between the species when coexcisting. Female European lobsters, close to moulting/spawning, were released in a tank with one European and one American male in a tank with two shelters available. The American and European males were dominant in half of the trials. Registrations were made of which lobsters where fighting, visiting another lobster, cohabitating and mating. Dominance had no importance. The European lobsters chose to interact more and for longer duration of time with each other. Mating, mating attempts and peaceful cohabitation occurred only between these lobsters. The American lobsters showed less social activity. It seems like it is a barrier between the species, where species-specific chemical communication probably is of importance. NORSK SAMMENDRAG: Siden europeisk og amerikansk hummer er så like at det er vanskelig å se forskjell, og de samtidig har tilsynelatende lik atferd og livshistorie, så ble det undersøkt hvorvidt hummeren selv kunne skille på art. Hunnhummer som ble vurdert til å være nær skallskifte/gyting ble introdusert til en europeisk og en amerikansk hann i et felleskar med to skjul. Den dominerende hannen var like ofte en amerikaner som en europeer, for å se om art eller dominans var viktig. Det ble registrert hvilke hummere som slåss, besøkte hverandre, delte skjul og parret seg. Dominans viste seg å være uten betydning. De europeiske hummerne fant fram til hverandre og brukte mest tid uansett aktivitet på hverandre. Parring og parringsforsøk forekom kun mellom europeisk hummer, i likhet med fredelig deling av skjul. Amerikansk hummer var gjennomgående mindre sosialt aktiv. Det ser ut til å være en barriere mellom artene, der artsforskjeller i kjemisk kommunikasjon trolig er til stede

Management implications of climate change effect on fisheries in Western Australia Part 1: Environmental change and risk assessment FRDC: Project No. 2010/535

Objectives: 1. Assess future climate change effects on Western Australia’s marine environment using a suite of IPCC model projections, downscaled to the key shelf regions and the spatial and temporal scales relevant for key fisheries 2. Examine the modeled shelf climate change scenarios on fisheries and implications of historic and future climate change effects 3. Review management arrangements to examine their robustness to possible effects of climate chang