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Unifying models have shown that the amount of space used by animals (e.g., activity space, home range) scales allometrically with body mass for terrestrial taxa; however, such relationships are far less clear for marine species. We compiled movement data from 1,596 individuals across 79 taxa collected using a continental passive acoustic telemetry network of acoustic receivers to assess allometric scaling of activity space. We found that ectothermic marine taxa do exhibit allometric scaling for activity space, with an overall scaling exponent of 0.64. However, body mass alone explained only 35% of the variation, with the remaining variation best explained by trophic position for teleosts and latitude for sharks, rays, and marine reptiles. Taxon-specific allometric relationships highlighted weaker scaling exponents among teleost fish species (0.07) than sharks (0.96), rays (0.55), and marine reptiles (0.57). The allometric scaling relationship and scaling exponents for the marine taxonomic groups examined were lower than those reported from studies that had collated both marine and terrestrial species data derived using various tracking methods. We propose that these disparities arise because previous work integrated summarized data across many studies that used differing methods for collecting and quantifying activity space, introducing considerable uncertainty into slope estimates. Our findings highlight the benefit of using large-scale, coordinated animal biotelemetry networks to address cross-taxa evolutionary and ecological questions. [ABSTRACT FROM AUTHOR]

Satellite derived sea surface temperatures (SSTs) are often used as a proxy for in situ water temperatures, as they are readily available over large spatial and temporal scales. However, contamination of satellite images can prohibit their use in coastal areas. We compared in situ temperatures to SST foundation (~10 m depth) at 31 sites inshore of the East Australian Current (EAC), the dynamic western boundary current of the south Pacific gyre, using an area averaging approach to overcome coastal contamination. Varying across- and along-shelf distances were used to area average SST measurements and de-correlation time scales were used to gap fill data. As the EAC is typically anisotropic (dominant along-shore flow) the choice of across-shelf distances influenced the correlation with in situ temperatures more than along-shelf distances. However, the “optimal” distances for both measurements were within known de-correlation length scales. Incorporating both SST area and time averaging (based on de-correlation time scales) produced data for an average of 96% of days that in situ loggers were deployed, compared to 27% (52%) without (with) area averaging. Temperature differences between the in situ data and SSTs varied depending on time of year, with higher differences in the austral summer when daily in situ temperatures can range by up to 4.20°C. The differences between the in situ and SST measurements were, however, significant with or without area averaging (t-test: p-values < 0.05). Nevertheless, when using the area averaging approaches SSTs were only an average of ~1.05°C different from in situ temperatures and less than in situ temperature fluctuations. Linear mixed models revealed that latitude, distance to the coast and nearest estuary did not influence the difference between the in situ and satellite data as much as the water depth. This study shows that using de-correlation length and time scales to inform how to process satellite data can overcome contamination and missing data thereby greatly increasing the coverage and utility of SST data, particularly in coastal areas.

Broad-scale acoustic telemetry networks are being established worldwide. The 10-year anniversary of the Integrated Marine Observing System's Animal Tracking Facility provided the opportunity to assess the efficiency of one of the first national-scale acoustic telemetry networks. Acoustic networks are comprised of acoustic receiver arrays that detect high-frequency transmitters attached to animals that pass within detection range. Herein we assessed the efficiency of eight curtains to detect passing animals by calculating the standardised mean number of detections and transmitters detected at each station. The aim was to determine how many receivers could be decommissioned fromeach curtain while maintaining its integrity (i.e. detection of all species passing the array). Pivotal locations were defined as the furthest station at which all species would still be detected and where at least 75%of the detections and transmitterswould still be detected. By applying these criteria, we were able to improve the cost-effectiveness of our network significantly, reducing the number of stations from 132 to 85 (64% of the original network), yet still retaining 84% of total detections, 86% of transmitters and 100% of detected species. The present study provides a useful framework for refining acoustic telemetry networks. [ABSTRACT FROM AUTHOR]

Phytoplankton abundance and distribution along the east coast of Australia are driven primarily by the southward flowing East Australian Current (EAC), which transports tropical water masses to temperate latitudes. The Solitary Islands Marine Park (SIMP, ~30°S) is located north of the EAC separation point (~32°S) in this tropical–temperate transition zone. In this study, we describe the oceanographic context (wind, current and nutrient load) during a wind-driven downwelling and a current-driven upwelling event, both sampled in austral winter only ten days apart. We investigate the effect of these contrasting oceanographic conditions on phytoplankton abundance, composition and distribution along a cross-shelf transect. During downwelling we find a cross-shelf transition in microphytoplankton composition from an offshore- to an inshore-community associated with nutrient gradients (nitrate and silicate). Strong vertical mixing leads to increased occurrences of benthic diatoms in near-shore surface waters. During upwelling conditions, elevated nutrient availability results in maximum microphytoplankton abundances (mainly oceanic diatoms) and increased species richness on the mid-shelf. An increase in dinoflagellates and silicoflagellates (mid-shelf) and the appearance of tropical phytoplankton (especially picoplankton and dinoflagellates, offshore) signals a strong impact of the EAC across all shelf communities. Nanoplankton are a major part of the winter phytoplankton community during both oceanographic regimes (~40–50% of TChl a). Our findings provide evidence of EAC-driven, nutrient-rich, slope water intrusion in the SIMP as expressed by cross-shelf phytoplankton variability. We suggest that rapid (~weekly) changes in phytoplankton composition along the east Australian coast are likely to be enhanced by the climate change-induced warming/strengthening of the EAC. [ABSTRACT FROM AUTHOR]

Zooplankton are the key trophic link between primary producers and fish in pelagic ecosystems. Historically, there are few Zooplankton time series in Australia, with no data sets longer than two years prior to 2008. Here we compile 98676 abundance records of more than 1000 Zooplankton taxa from unpublished research cruises, student projects, published literature, and the recent Integrated Marine Observing System (IMOS). This data set covers the entire coastal and shelf region of Australia and dates back to 1938. Most records are for copepods, but there are also data for other taxa such as decapods, chaetognaths, thaliaceans, appendicularians, and cladocerans. Metadata are provided for each record, including dates, coordinates, and information on mesh size and sampling methods. To facilitate analysis across the multiple data sets, we have updated the species names according to the World Register of Marine Species (WoRMS) and converted units to abundance per cubic meter. These data will be valuable for studies of biodiversity, biogeography, impacts of climate change, and ecosystem health. We encourage researchers holding additional Australian Zooplankton data to contact us and contribute their data to the data set so we can periodically publish updates. [ABSTRACT FROM AUTHOR]