Australian Coastline Research Articles

Long-term migration patterns and bisexual philopatry in a benthic shark species

Knowledge of the broad-scale movement patterns of sharks is essential to developing effective management strategies. Currently there is a large bias in studies focusing on species that are either large apex predators or found in tropical to subtropical regions. There is limited knowledge of the movements and migrations of benthic and temperate shark species. The present study used passive acoustic telemetry to investigate the movement patterns of a benthic shark species, the Port Jackson shark (Heterodontus portusjacksoni). Individuals were tagged with acoustic transmitters between 2012 and 2014 and their movements were monitored within Jervis Bay and along the east Australian coastline for up to 4 years. Male and female Port Jackson sharks demonstrated high levels of philopatry to both Jervis Bay and their tagging location across multiple years. Although males and females did not differ in their arrival times, females departed from Jervis Bay later than males. Approximately half the tagged individuals migrated in a southward direction, with individuals being detected at Narooma, Bass Strait and Cape Barron Island. This study provides conclusive evidence of bisexual philopatry in a benthic temperate shark species, confirming previous hypotheses, and presents the most detailed migration route for Port Jackson sharks to date.

Invigorating ocean boundary current systems around Australia during 1979–2014: As simulated in a near‐global eddy‐resolving ocean model

AbstractOcean boundary currents, transporting water masses and marine biota along the coastlines, are important for regional climate and marine ecosystem functions. In this study, we review the dominant multi‐decadal trends of ocean boundary currents around Australia. Using an eddy‐resolving global ocean circulation model, this study has revealed that the major ocean boundary current systems around Australia, the East Australian Current (EAC), the Indonesian Throughflow (ITF), the Leeuwin Current, the South Australian Current and the Flinders Current, have strengthened during 1979–2014, consistent with existing observations. Eddy energetics in the EAC, the ITF/South Equatorial Current in the southeast Indian Ocean, and the Leeuwin Current have also enhanced during the same period. The multi‐decadal strengthening of the ocean boundary current systems are primarily driven by large scale wind patterns associated with the dominant modes of climate variability and change – the phase shift of the Inter‐decadal Pacific Oscillation/Pacific Decadal Oscillation strengthens the ITF and the Leeuwin Current/South Australian Current; and the poleward shift and strengthening of surface winds in the subtropical gyres reinforce the EAC and the Flinders Current. The invigorating ocean boundary current systems have induced extreme oceanographic conditions along the Australian coastlines in recent years, including the poleward shift of marine ecosystems off the east coast of Australia and the consecutive Ningaloo Niño – marine heatwave events off the west coast during 2011–2013. Understanding long‐term trends and decadal variations of the ocean boundary currents is crucial to project future changes of the coastal marine systems under the influence of human‐induced greenhouse gas forcing.

Synchronised patterns of erosion and deposition observed at two beaches

A similarity in the observed variability through time of two or more individual beaches (here quantified by synchronous changes in shoreline position and subaerial sand volume) can have significant implications to the increased focus worldwide on the need for expanded coastal monitoring. If it can be established that one or a select few beach sites exhibit ‘regionally representative’ behaviour in response to varying and/or changing wave and other climatic forcing, then this will assist to guide the extent and scope of the ongoing monitoring effort required. In this study, two beaches located on the southeast Australian coastline of similar size and orientation but separated by 35km, were simultaneously monitored and compared for a period spanning 3years. Intensive sub-aerial surveys were conducted each month at both sites using ATV-mounted RTK-GNSS. The purpose was to establish whether detailed, embayment wide patterns of erosion and deposition quantified at either site were indicative of the behaviour observed at the other.During the data collection period, storm wave events caused substantial fluctuations in monthly sub-aerial sand volumes (in the range of 60–70% of mean volume), including month-to-month changes at the berm and episodic foredune erosion and recovery. Principal component analysis of the two beaches revealed that both were dominated by oscillation (corresponding north–south behaviour) rather than rotation (contrasting north–south behaviour) over this three-year period. Comparison of alongshore-averaged volume time-series between the two sites indicated a similar total range (68m3/m and 78m3/m) and the average difference between the two sites (4.5m3/m) was found to be of the order of 50% of the average monthly change (9.7m3/m and 10.2m3/m). Corresponding spatial patterns in the occurrence of erosion/accretion along the two sites were also compared and found to closely correspond. Five synchronised ‘snap-shot’ observations from historical aerial photogrammetry and surveys at both sites spanning the period 1974 to 2011 (one per decade) suggest coherence between the sites extends beyond the three-year intensive monitoring period reported here.

Latitudinal gradients in ecosystem engineering by oysters vary across habitats.

Ecological theory predicts that positive interactions among organisms will increase across gradients of increasing abiotic stress or consumer pressure. This theory has been supported by empirical studies examining the magnitude of ecosystem engineering across environmental gradients and between habitat settings at local scale. Predictions that habitat setting, by modifying both biotic and abiotic factors, will determine large-scale gradients in ecosystem engineering have not been tested, however. A combination of manipulative experiments and field surveys assessed whether along the east Australian coastline: (1) facilitation of invertebrates by the oyster Saccostrea glomerata increased across a latitudinal gradient in temperature; and (2) the magnitude of this effect varied between intertidal rocky shores and mangrove forests. It was expected that on rocky shores, where oysters are the primary ecosystem engineer, they would play a greater role in ameliorating latitudinal gradients in temperature than in mangroves, where they are a secondary ecosystem engineer living under the mangrove canopy. On rocky shores, the enhancement of invertebrate abundance in oysters as compared to bare microhabitat decreased with latitude, as the maximum temperatures experienced by intertidal organisms diminished. By contrast, in mangrove forests, where the mangrove canopy resulted in maximum temperatures that were cooler and of greater humidity than on rocky shores, we found no evidence of latitudinal gradients of oyster effects on invertebrate abundance. Contrary to predictions, the magnitude by which oysters enhanced biodiversity was in many instances similar between mangroves and rocky shores. Whether habitat-context modifies patterns of spatial variation in the effects of ecosystem engineers on community structure will depend, in part, on the extent to which the environmental amelioration provided by an ecosystem engineer replicates that of other co-occurring ecosystem engineers.

Beach response to Australian East Coast Lows: A comparison between the 2007 and 2015 events, Narrabeen-Collaroy Beach

ABSTRACT Harley, M.D.; Turner, I.L.; Splinter, K.D.; Phillips, M.S., and Simmons, J.A., 2016. Beach response to Australian East Coast Lows: a comparison between the 2007 and 2015 events, Narrabeen-Collaroy Beach. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 388–392. Coconut Creek (Florida), ISSN 0749-0208. East Coast Lows (ECLs) are intense extratropical cyclones that form off the east Australian coastline and are known to cause significant beach erosion. This study presents analysis of the beach response to two severe ECLs that occurred in the Sydney region in June 2007 and April 2015 based on a three-dimensional coastal monitoring program undertaken at Narrabeen-Collaroy Beach. The results indicate considerable reductions in the subaerial sand volume for both storms, with an average (maximum) reduction of 78 m3 (124 m3) per alongshore meter f...

Does the whale shark aggregate along the Western Australian coastline beyond Ningaloo Reef?

Whale sharks (Rhincodon typus) seasonally aggregate at Western Australia’s Ningaloo Reef in the austral autumn and winter, but their occurrence beyond this region during spring and summer remains elusive. The aggregation at Ningaloo Reef coincides with a pulse of productivity following mass coral spawning in early autumn, with the population during this period dominated by juveniles that amass for feeding purposes. To investigate their movement patterns beyond Ningaloo Reef, whale sharks were fitted with SPOT (n = 13) or SPLASH (n = 1) tags between April and September (2010–14). Tagged whale sharks ranged in total length from 3 to 9 m. Each whale shark was also photographed for its subsequent identification using Wildbook for Whale Sharks, and their years of residency at Ningaloo Reef determined. Temporal and spatial observations of whale shark sightings were also determined through the conducting of interviews with people throughout 14 coastal towns along the Western Australian coastline, as well as through historical sightings and the Wildbook database. Satellite tracking revealed that all sharks remained relatively close to the Western Australian coast, travelling a mean minimum distance of 1667 (±316, s.e.) km. Public reports, coupled with satellite tracking, demonstrated that whale sharks inhabit most of the Western Australian coast (from 35°S to 12°S), and that seasonal migrations beyond Ningaloo Reef may be to the north or south and may similarly be associated with areas of increased productivity.

A new species of Near-shore Marine Goby (Pisces: Gobiidae: Nesogobius)from Kangaroo Island, Australia.

Nesogobius is one of two goby genera with all species wholly restricted to temperate Australian waters. Described here is a new member of the genus discovered during near-shore marine and estuarine fish sampling along the central southern Australian coastline. The tiger sandgoby Nesogobius tigrinus sp. nov. is distinguished from other congeners by a combination of colouration including four prominent vertical black bars on males; morphological characters involving body scales (large), head scales (naked), body depth (slender) and gill opening (wide); meristic counts including a lack of second dorsal and anal fin spines; and mitochondrial DNA sequence divergence. The species appears to be a narrow range endemic, restricted to specific sub-tidal habitat in the unique sheltered embayments of northeast Kangaroo Island. This study forms part of ongoing investigations to more fully describe the biodiversity and conservation requirements of the regional ichthyofauna.

Integrative taxonomy ofParasabellaandSabellomma(Sabellidae: Annelida) from Australia: description of new species, indication of cryptic diversity, and translocation of some species out of their natural distribution range

Most nominal fan worm species belonging to the genus Parasabella Bush, 1905, and Sabellomma Nogueira, Fitzhugh & Silva-Rossi, 2010 (Sabellidae, Annelida) lack unique morphological diagnostic features. Species diagnoses rely on a combination of attributes, often making reference to characters that are qualitatively or quantitatively continuous. This, together with a lack of knowledge about phenotypic intraspecific variation in most species, suggests that the sole use of morphological features is insufficient to identify and characterize some of these species. Examination of collections revealed that Parasabella is a common and diverse group of sabellids along the Australian coastline, although it had only been recorded here twice. The genus Sabellomma is here reported in Australia for the first time. Comparison of morphological data and nuclear (internal transcribed spacer) and mitochondrial (cytochrome oxidase I) DNA sequence data of 30 terminals in a range of analyses allowed us to assess the monophyly of Parasabella and its sister-group relationship with Sabellomma and to examine some of the species boundaries and genetic diversity within lineages. The combined sequence data results indicate the presence of seven distinct genetic Parasabella lineages in Australia, four of which are assigned to previously described species (three are new records for Australia), and two are considered as a complex of species sharing a unique combination of characters, one of which is described as new. Another Parasabella species with distinct atypical radiolar eyes and a species of Sabellomma are also described as new. © 2015 The Linnean Society of London

Rapid relative sea-level fall along north-eastern Australia between 1200 and 800 cal. yr BP: An appraisal of the oyster evidence

A fast-paced post-glacial sea-level rise and subsequent mid-Holocene sea-level highstand are well documented at several far field locations away from the presence of former ice sheets but sea-level development during the late Holocene remains ambiguous. In this study, we present new data from modern and fossil oysters attached to shoreline rocks along the north-eastern Australian coastline that reveal new constraints on the nature and timing of relative sea-level change over the past 2500yr. Surveyed elevations of various contemporary oyster zones contextualize modern oyster growth forms in relation to sea-level datum and build the reference for our fossil oyster data. Based on survey data and field observations we developed a robust set of criteria for measuring fossil oysters to determine their relative sea-level position and constrain the uncertainties associated with these reconstructions. Thick (>10cm) fossil oyster visors above the equivalent modern growth suggest higher relative sea-levels in the past (i.e. >1200cal.yrBP). Radiocarbon analyses of the modern oyster visors suggest continuous lateral accumulation over the past ~800yr which implies relatively stable sea-level over this period. The modern and fossil dataset defines a distinct and rapid relative ~1m sea-level fall between 1200 and 800cal.yrBP. Whether the sea-level fall was stepped or followed a broader smooth/monotonic pattern is unclear. The timing coincides with the initiation of some inshore fringing coral reefs in the Great Barrier Reef region and other major geomorphological changes along the coastal zone. A combination of various factors may have been the driving mechanism behind this relative sea-level fall with rates between 1.0 to 5.2mmyr−1.

Information for Australian impact and adaptation planning in response to sea-level rise

Sea levels along Australia's coastline are influenced by natural climate variability and anthropogenic climate change. Projections of sea-level rise (SLR) for 2090 for the Australian coast-line are similar to the global mean sea-level projections. The global and regional projections are almost independent of the Representative Concentration Pathways (RCPs) for greenhouse gas emissions chosen for the first decades of the 21st century, but they begin to diverge significantly from about 2050. For the business-as-usual scenario (RCP8.5), the rates increase steadily through the 21st century, reaching almost 12 mm yr-1 by 2100 at all locations. For the inter-mediate scenarios of RCP 6.0 and RCP 4.5, the rates stabilise in about 2090 and 2060 at about 7-8 and 6 mm yr-1, respectively. For the strong mitigation scenario (RCP 2.6, requiring significant and urgent mitigation of greenhouse gas emissions), the rate of rise stabilises much earlier than the other scenarios and then reduces slightly to about 4 mm yr-1. On the north and west coasts of Australia, the observed sea-level trends from the start of the projections in 1996 to 2010 are larger than the model projections as a result of the combined effect of SLR and internal modes of climate variability. The impacts of SLR will be felt most profoundly during extreme sea-level events. The meteorological and climate processes that contribute to extreme sea levels around the coast of Australia are highly regionally heterogeneous. Allowances were calculated that provide estimates of the height that present assets or their protective measures would need to be raised to ensure that the likelihood of exceedance of those levels in the future does not change from the present climate. These allowances vary according to SLR projections, their uncertainties and the variability of extreme sea levels. For 2030, when the uncertainty surrounding future SLR scenarios is small, the allowances are approximately the median projected SLR. However by 2090, the larger uncertainties associated with the projections lead to allowances that typically lie to-wards the upper end of the range of projected SLR.

Erratum to: Metal distributions in seawater, sediment and marine benthic macroalgae from the South Australian coastline

Algal species which are ubiquitous along the coastlines of many countries reflect the environmental conditions of the coastal seawater and may serve as useful biomonitors of anthropogenic pollution. Heavy metal concentrations of ten elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of potential environmental concern were determined in seawater, sediments and twelve species of benthic marine macroalgae from four locations (Glenelg, Port Adelaide, Port Broughton and Port Pirie) along the South Australian coastline. The four sites chosen represented varying degrees of metal contamination, where the capacity for benthic macroalgae to accumulate heavy metals from the environment was evaluated. Spatial differences in heavy metal concentration in both seawaters and sediments were observed at all sites with the highest concentrations of heavy metals including Cd (125 μg g−1), Pb (2,425 μg g−1) and Zn (7,974 μg g−1) found in the finer sediment fractions (<250 μm) of Port Pirie. While all algal species studied (Acrosorium polyneurum, Anotrichium tenue, Cystophora Cephalornithos Cystophora monillifera, Cystophora monilliformis, Dictyopteris australis, Gelidium micropterum, Gracilaria, Hormophysa Cuneiformis, Sargassum cinctum, Scaberia agardhii and Ulva lactuca) accumulated metals to varying degrees, Blindigia marginata was a good biomonitor species for a number of metals including Cd, Co, Cr, Fe, Pb and Zn, exhibiting both relatively high total metal concentrations and significant concentration factors.

First photographic records of the giant manta ray Manta birostris off eastern Australia.

We present the first photographic evidence of the presence of the giant manta ray Manta birostris in east Australian waters. Two individuals were photographed off Montague Island in New South Wales and off the north east coast of Tasmania, during summer 2012 and 2014, respectively. These sightings confirm previous unverified reports on the species occurrence and extend the known distribution range of M. birostris to 40°S. We discuss these findings in the context of the species’ migratory behaviour, the regional oceanography along the south east Australian coastline and local productivity events.

Is There Any Need for a Dike to Save Melbourne from the Rising Seas?

The Australian government is still basing policy on the concept that sea level will rise by 1.1 meters along the Australian coastline by 2100. The Department of the Environment has proposed a 10 billion dollar dike to save Melbourne from the hypothetical rising sea. In reality the tide gauges of Victoria are recording average relative rates of rise of less than 1 mm/year, in perfect agreement with the National average. At this rate sea level will rise by only 8.5 cm by 2100 but even this estimate may be too high. The worldwide average sea level rise, based on only tide gauges of sufficient quality and length, is only about 0.25 mm/year, with zero acceleration over the last few decades. Such a rise can be dealt with by local adaption, as in the last 100 years, and there is no need for any engineering structures, let alone the proposed 10'billion dollar scheme with its accompanying environmental and social problems.

Seasonal rainfall totals of Australian stations can be modelled with distributions from the Tweedie family

ABSTRACTTheoretical probability distributions of seasonal rainfall totals have potential applications in fitting models and generating synthetic data. One of the major challenges in fitting distributions for seasonal rainfall from countries like Australia is that the data differ significantly for various seasons across stations. The wet stations may possess strictly positive rainfall amounts only, whereas dry stations may observe seasons with no rainfall. Furthermore the data ranges from approximately symmetric to highly skewed. We explore fitting distributions from the Tweedie family of distributions to model seasonal rainfall. The Tweedie family of distributions includes continuous‐symmetric (normal), continuous‐skewed (gamma) and mixture‐type (Poisson–gamma, P–G) distributions. This study analysed seasonal rainfall totals from 989 Australian stations with data for about 100 years. For various seasons, within the Tweedie family the P–G distributions were optimal for about 50% of stations, the gamma distributions were near‐optimal for approximately 40% and the normal distributions were near‐optimal elsewhere. Most of the stations where the gamma distributions are near‐optimal are concentrated on the Australian coastline. The quantile–quantile (QQ) plots indicate that the models fit well to the seasonal rainfall totals of selected stations. Almost everywhere, various statistics of observed seasonal rainfall are within the empirical 95% confidence intervals of the respective statistics of simulated data using the Tweedie models. The model performs better in modelling extremely high rainfall events (95th percentiles) than the extremely low (5th percentiles) rainfall events. In addition, the P–G distribution within the Tweedie family models the probability of no rainfall and, for about 97% of stations, the observed probability of no rainfall is within the 95% confidence interval of the simulated probability of no rainfall. The ability of the Tweedie models to simulate the extreme rainfall amounts and the probability of no rainfall can be useful in drought monitoring and in water resources planning and management.

A spatial simulation model for the dispersal of the bluetongue vector Culicoides brevitarsis in Australia.

BackgroundThe spread of Bluetongue virus (BTV) among ruminants is caused by movement of infected host animals or by movement of infected Culicoides midges, the vector of BTV. Biologically plausible models of Culicoides dispersal are necessary for predicting the spread of BTV and are important for planning control and eradication strategies.MethodsA spatially-explicit simulation model which captures the two underlying population mechanisms, population dynamics and movement, was developed using extensive data from a trapping program for C. brevitarsis on the east coast of Australia. A realistic midge flight sub-model was developed and the annual incursion and population establishment of C. brevitarsis was simulated. Data from the literature was used to parameterise the model.ResultsThe model was shown to reproduce the spread of C. brevitarsis southwards along the east Australian coastline in spring, from an endemic population to the north. Such incursions were shown to be reliant on wind-dispersal; Culicoides midge active flight on its own was not capable of achieving known rates of southern spread, nor was re-emergence of southern populations due to overwintering larvae. Data from midge trapping programmes were used to qualitatively validate the resulting simulation model.ConclusionsThe model described in this paper is intended to form the vector component of an extended model that will also include BTV transmission. A model of midge movement and population dynamics has been developed in sufficient detail such that the extended model may be used to evaluate the timing and extent of BTV outbreaks. This extended model could then be used as a platform for addressing the effectiveness of spatially targeted vaccination strategies or animal movement bans as BTV spread mitigation measures, or the impact of climate change on the risk and extent of outbreaks. These questions involving incursive Culicoides spread cannot be simply addressed with non-spatial models.

Reproduction, growth and mortality of the exploited sillaginid,Sillago ciliataCuvier, 1829

Summary The goal of this study was to examine the age and size composition, growth, reproductive biology and mortality of Sillago ciliata Cuvier, 1829 in one of the largest estuarine commercial fisheries in south-eastern Australia. The study also aimed to present a qualitative comparison of latitudinal variations in some of these characteristics along the eastern Australian coastline. The sampled population contained fish aged up to 10 years with a maximum size of 39.2 cm fork length (LF), and was dominated by 1–5 year olds. Sexual divergence in both the age and size structure of the population was recorded. Female S. ciliata grew slightly faster and attained a greater maximum size (L∞ = 33.79 cm LF, k = 0.50 year−1 and t0 = −0.57 years) than males (L∞ = 29.73 cm LF, k = 0.49 year−1 and t0 = −0.67 years). Females also matured at a significantly larger size (19.13 cm) and older age (1.63 years) than males (size: 17.07 cm, age: 1.10 years). Reproductive activity was highest between September and March. There were no differences between males and females in terms of mortality rate; the estimated total population, natural and fishing mortality rates were Z = 0.64, M = 0.42 and F = 0.22, respectively. Although these mortality rates suggest that S. ciliata in the Clarence River are relatively resilient to current rates of exploitation, regular monitoring of their commercial and recreational catch as well as their population structure is recommended in order to maintain sustainable fisheries. Potential latitudinal shifts in the spawning period, age structure and growth of S. ciliata along eastern Australia were also revealed.

Too much data is never enough: A review of the mismatch between scales of water quality data collection and reporting from recent marine dredging programmes

Water quality monitoring programmes have become integral components of efforts to identify the impact(s) of anthropogenic activities. In many programmes, however, it appears records are being collected at finer temporal scales than required to produce the information needed by end-users (e.g. managers). Such mismatches are of concern given that the effort and expense invested in collection and processing of unexploited records is effectively wasted. Consequently, we were interested in reviewing the temporal scales over which water quality records have been collected, analysed and reported in monitoring programmes. Our case study focussed on turbidity (NTU) records collected from the monitoring of key dredging programmes (n=8) initiated on the northern Australian coastline between 2006 and 2012. The review of (primarily grey) literature revealed that (a) there has been an increase in the number of turbidity records collected per day over time, a pattern driven by fine scale temporal records being taken at an increasing number of sites, and, (b) although these records are typically acquired multiple times per day for all loggers, a daily summary measure is commonly reported (e.g. median, rolling or exponentially weighted moving average), with some programmes reporting a subset of the spatial detail acquired (e.g. averages of dual loggers, exclusion of records from ‘backup’ stations). This pattern of analysis and reporting removes fine scale detail from summaries provided to end-users, driving monitoring programmes to become relatively ‘data-rich but information-poor’. We suggest that iteratively designing monitoring programmes based on the outcomes of previous experiences could facilitate the collection of datasets with higher information content (i.e. fewer records that are not used to produce information), ultimately increasing the efficiency of future monitoring programmes.

Mapping soil salinity and pH across an estuarine and alluvial plain using electromagnetic and digital elevation model data

AbstractIncreasing pressures from agriculture and urbanization have resulted in drainage of many floodplains along the eastern Australian coastline, which are underlain by sulphidic sediments, to lower water tables and reduce soil salinity. This leads to oxidation of the sediments with a rapid decline in pH and an increase in salinity. Accurately mapping soil salinity and pH in coastal acid sulphate soil (CASS) landscapes is therefore important. One required map is the extent of highly acidic (i.e. pH &lt; 4.5) areas, so that the application of alkaline amendments (e.g. lime) to neutralize the acid produced can be specifically targeted to the variation in pH. One approach is to use digital soil mapping (DSM) using ancillary information, such as an EM38, digital elevation models (DEM – elevation) and trend surface parameters (east and north). We used an EM38 in the horizontal (EM38h) and vertical (EM38v) modes together with elevation data to develop multiple linear regressions (MLR) for predicting EC1:5 and pH. For pH, best results were achieved when the EM38 ECa data were log‐transformed. By comparing MLR models using REML analysis, we found that using all ancillary data was optimal for mapping EC1:5, whereas the best predictors for pH were north, log‐EM38v and elevation. Using residual maximum likelihood (REML), the final EC1:5 and pH maps produced were consistent with previously defined soil landscape units, particularly CASS. The DSM approach used is amenable for mapping saline soils and identifying areas requiring the application of lime to manage acidic soil conditions in CASS landscape.

Migratory Movements of Pygmy Blue Whales (Balaenoptera musculus brevicauda) between Australia and Indonesia as Revealed by Satellite Telemetry

In Australian waters during the austral summer, pygmy blue whales (Balaenoptera musculus brevicauda) occur predictably in two distinct feeding areas off western and southern Australia. As with other blue whale subspecies, outside the austral summer their distribution and movements are poorly understood. In order to describe the migratory movements of these whales, we present the satellite telemetry derived movements of eleven individuals tagged off western Australia over two years. Whales were tracked from between 8 and 308 days covering an average distance of 3,009±892 km (mean ± se; range: 832 km–14,101 km) at a rate of 21.94±0.74 km per day (0.09 km–455.80 km/day). Whales were tagged during March and April and ultimately migrated northwards post tag deployment with the exception of a single animal which remained in the vicinity of the Perth Canyon/Naturaliste Plateau for its eight day tracking period. The tagged whales travelled relatively near to the Australian coastline (100.0±1.7 km) until reaching a prominent peninsula in the north-west of the state of Western Australia (North West Cape) after which they travelled offshore (238.0±13.9 km). Whales reached the northern terminus of their migration and potential breeding grounds in Indonesian waters by June. One satellite tag relayed intermittent information to describe aspects of the southern migration from Indonesia with the animal departing around September to arrive in the subtropical frontal zone, south of western Australia in December. Throughout their migratory range, these whales are exposed to impacts associated with industry, fishing and vessel traffic. These movements therefore provide a valuable tool to industry when assessing potential interactions with pygmy blue whales and should be considered by conservation managers and regulators when mitigating impacts of development. This is particularly relevant for this species as it continues to recover from past exploitation.

Confirming the lack of any sea level acceleration around the Australian coastline

Confirming the lack of any sea level acceleration around the Australian coastline