Distribution of Palinuridae and Scyllaridae phyllosoma larvae within the East Australian Current: a climate change hot spot

Many marine species are predicted to shift their ranges poleward due to rising ocean temperatures driven by climate change. For benthic marine species with pelagic larval stages, poleward range shifts are often facilitated through pelagic larval transport via western boundary currents (WBC). By surveying pelagic larval distributions within WBCs, species advected poleward of their known distributions can be identified and monitored. Palinurid and scyllarid lobster larvae (phyllosoma) have long pelagic larval durations, providing high potential for poleward advection. We surveyed spatial distribution of phyllosoma within the western-boundary East Australian Current. Due to difficulties morphologically identifying phyllosoma, we tested the utility of molecular identification using cytochrome c oxidase I (COI). From COI sequences of 56 phyllosoma and one postlarva, 65% of sequences consisted of good-quality mitochondrial DNA. Across water types sampled, scyllarid phyllosoma exhibited relatively homogeneous distribution, whereas palinurid phyllosoma exhibited heterogeneous distribution with greatest abundance inside a warm core eddy on the south coast of eastern Australia. Two tropical and one subtropical palinurid species were detected ~75–1800 km to the south or south-west of their known species distribution. Our results indicate tropical lobster species are reaching temperate regions, providing these species the opportunity to establish in temperate regions if or when environmental conditions become amenable to settlement

Outlier SNPs detect weak regional structure against a background of genetic homogeneity in the Eastern Rock Lobster, Sagmariasus verreauxi

Genetic differentiation is characteristically weak in marine species making assessments of population connectivity and structure difficult. However, the advent of genomic methods has increased genetic resolution, enabling studies to detect weak, but significant population differentiation within marine species. With an increasing number of studies employing high resolution genome-wide techniques, we are realising that the connectivity of marine populations is often complex and quantifying this complexity can provide an understanding of the processes shaping marine species genetic structure and to inform long-term, sustainable management strategies. This study aims to assess the genetic structure, connectivity, and local adaptation of the Eastern Rock Lobster (Sagmariasus verreauxi), which has a maximum pelagic larval duration of 12 months and inhabits both subtropical and temperate environments. We used 645 neutral and 15 outlier SNPs to genotype lobsters collected from the only two known breeding populations and a third episodic population—encompassing S. verreauxi's known range. Through examination of the neutral SNP panel, we detected genetic homogeneity across the three regions, which extended across the Tasman Sea encompassing both Australian and New Zealand populations. We discuss differences in neutral genetic signature of S. verreauxi and a closely related, co-distributed rock lobster, Jasus edwardsii, determining a regional pattern of genetic disparity between the species, which have largely similar life histories. Examination of the outlier SNP panel detected weak genetic differentiation between the three regions. Outlier SNPs showed promise in assigning individuals to their sampling origin and may prove useful as a management tool for species exhibiting genetic homogeneity

Argo Project: Machine vision based motion capture for tracking the trajectory of the pose of a mobile rigid body

The objective of the Argo Project is to develop a tool that will track in real-time the motion of unconstrained, self-propelled, model ships in seakeeping tests done in towing tanks and manoeu-vring basins. To meet the unconstrained requirement, the tracking system must be non- contact and can not interfere with the operation or motion of the model ship. An additional operating requirement is that the sensor must cover an area in excess of thirty square metres. An optical based sensor was selected as it satisfied these constraints. Tracking the motion of the model ship is achieved with a predictive, extended Kalman filter (EKF), using feature point extraction from multiple synchronized images. The EKF is used because it can readily integrate and filter multiple noisy data sets. As well, it can generate an estimate of the pose, namely the position and orientation, of the model ship relative to the reference frame of the test tank. While this project is focused on ship tracking there are many other applications for a system of this kind. TM The system under development makes use of the Qualisys camera and video processor hardware that extract image feature points and return them to a host computer. The incoming image TM feature points are then fed into tracking software developed in MATLAB . The tracking software uses estimates of the image to do feature point correspondence and sorts the incoming data vector into the expected order. The sorted data vector is then used as the input vector for the EKF which computes the photogrammetric equations and computes the state vector for the pose of the mobile object being tracked. This work is being undertaken at the University of British Columbia (UBC), Deparment of Mechanical Engineering, Maritime Engineering and Naval Architecture Research Laboratory. The organizaitons that assisted in this research effort are the Centre for Cold Ocean Resources Engineering, Intelligent Systems GroupApplied Science, Faculty ofMechanical Engineering, Department ofGraduat

Mesoscale circulation determines broad spatio-temporal settlement patterns of lobster.

The influence of physical oceanographic processes on the dispersal of larvae is critical for understanding the ecology of species and for anticipating settlement into fisheries to aid long-term sustainable harvest. This study examines the mechanisms by which ocean currents shape larval dispersal and supply to the continental shelf-break, and the extent to which circulation determines settlement patterns using Sagmariasus verreauxi (Eastern Rock Lobster, ERL) as a model species. Despite the large range of factors that can impact larval dispersal, we show that within a Western Boundary Current system, mesoscale circulation explains broad spatio-temporal patterns of observed settlement including inter-annual and decadal variability along 500 km of coastline. To discern links between ocean circulation and settlement, we correlate a unique 21- year dataset of observed lobster settlement (i.e., early juvenile & pueruli abundance), with simulated larval settlement. Simulations use outputs of an eddy-resolving, data-assimilated, hydrodynamic model, incorporating ERL spawning strategy and larval duration. The latitude where the East Australian Current (EAC) deflects east and separates from the continent determines the limit between regions of low and high ERL settlement. We found that years with a persistent EAC flow have low settlement while years when mesoscale eddies prevail have high settlement; in fact, mesoscale eddies facilitate the transport of larvae to the continental shelf-break from offshore. Proxies for settlement based on circulation features observed with satellites could therefore be useful in predicting broadscale patterns of settlement orders of magnitudes to guide harvest limits

Population genomics of the Eastern Rock Lobster, Sagmariasus verreauxi, during spawning stock recovery from over-exploitation

Fisheries are currently under pressure to provide increasing amounts of seafood, causing a growing number of marine stocks to be harvested at unsustainable levels. To ensure marine resources remain sustainable, careful management of biological stocks and their genetic integrity is required. The Eastern Rock Lobster, Sagmariasus verreauxi, is commercially harvested along the New South Wales (NSW) coast of eastern Australia and is managed as a single unit. Due to overfishing, the NSW S. verreauxi stock was severely depleted in the mid-1990s but has since been rebuilding. This study evaluates the population genetic structure, putative local adaptation, and potential of a population bottleneck for NSW S. verreauxi. Using neutral single nucleotide polymorphisms (SNPs), we determined NSW S. verreauxi consist of a single genetic stock, with outlier SNPs detecting weak genetic divergence among offshore locations, and evidence of population bottlenecks at all locations. Our findings (i) confirm a single management unit is appropriate; (ii) can be used as a baseline for future genetic monitoring of NSW S. verreauxi; and (iii) highlights the importance of implementing routine genetic monitoring and collecting temporal samples to understand the full impact of overfishing on a species resilience

Migrate-N input file

Input file containing 50 loci for Migrate-n analysis between NSW and NZ

Data from: Outlier SNPs detect weak regional structure against a background of genetic homogeneity in the Eastern Rock Lobster, Sagmariasus verreauxi

Genetic differentiation is characteristically weak in marine species making assessments of population connectivity and structure difficult. However the advent of genomic methods have increased genetic resolution, enabling studies to detect weak, but significant population differentiation within marine species. With an increasing number of studies employing high resolution genome-wide techniques, we are realising the connectivity of marine populations is often complex and quantifying this complexity can provide an understanding of the processes shaping marine species genetic structure and to inform long-term, sustainable management strategies. This study aims to assess the genetic structure, connectivity and local adaptation of the Eastern Rock Lobster (Sagmariasus verreauxi), which has a maximum pelagic larval duration of 12 months and inhabits both subtropical and temperate environments. We used 645 neutral and 15 outlier SNPs to genotype lobsters collected from the only two known breeding populations and a third episodic population — encompassing S. verreauxi’s known range. Through examination of the neutral SNP panel, we detected genetic homogeneity across the three regions, which extended across the Tasman Sea encompassing both Australian and New Zealand populations. We discuss differences in neutral genetic signature of S. verreauxi and a closely-related, co-distributed rock lobster, Jasus edwardsii, determining a regional pattern of genetic disparity between the species, which have largely similar life histories. Examination of the outlier SNP panel detected weak genetic differentiation between the three regions. Outlier SNPs showed promise in assigning individuals to their sampling origin and may prove useful as a management tool for species exhibiting genetic homogeneity

Full SNP panel (756 SNPs)

756 SNPs that were identified for Sagmariasus verreauxi in a genpop file format