Vincent Raoult results 38
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Differences in diet have implications for potential ecosystem roles of two key rocky reef fishNARA Subscribed
The influence of fishes on temperate rocky reef ecosystems is globally recognised, particularly where large predators may structure ecosystems through predation. In South-East Australia, the common Wrasse Achoerodus viridis (Blue Groper) and Sparid Chrysophrys auratus (Snapper) are sympatric rocky reef predators. While their diets are thought to be well understood, this is generally based on gut contents undertaken over limite...
Urchin diets are a topic of global interest due to their impacts on subtidal reefs. Urchins can consume large amounts of macroalgae, leading to the loss of macroalgal forests and creation of “barrens”. However, there is scant dietary information in the southern hemisphere for the temperate sea urchin, Centrostephanus rodgersii , and what they consume within barrens, which lack macroalgae. Here, we sampled C. rodgersii to quant...
Stable isotope analysis reveals resource use by rays in an Australian temperate estuaryNARA Subscribed
Estuarine ecosystems are increasingly threatened by anthropogenic activities that deplete or replace natural habitats. This may lead to cascading effects in estuarine food webs as the availability of primary producers changes. Rays are ecosystem engineers that feed in sedimentary environments, yet their main prey items and the primary producers supporting their nutrition are unknown. The aim of this study was to assess resourc...
There is an urgent need for improved monitoring approaches to rapidly and accurately assess sea cucumber populations at ecologically relevant scales. Timely surveys are critical for informing effective fisheries management and decision-making. Traditional surveys, undertaken via snorkelling, manta tows, or SCUBA, are limited to shallow and accessible areas; however, sea cucumbers inhabit a broad range of depths, including area...
Quantitatively assessing mortality post coral bleaching at scale is inherently difficult, yet can be achieved with georeferenced imagery from aerial drones. Here, we assess the coral bleaching mortality rate from the 2024 global bleaching event at the iconic Lizard Island, Australia. Using drone-derived orthomosaics of the northern and southern sides of the island collected during and after the bleaching event, we measured the...
Quantifying the trophic role of a species is key to understanding its ecology and ecological role. Their trophic role can influence community composition, ecosystem stability, and nutrient transport and cycling between habitats through ingestion, egestion, and excretion, which requires an understanding of species diet and habitat use. Despite the regular occurrence of sawsharks in Australian temperate fisheries, there remains...
Patterns of mother–embryo isotope fractionation in batoids vary within and between speciesNARA Subscribed
Patterns of mother–embryo fractionation of 13 C and 15 N were assessed for their predictability across three species of batoids caught as by‐catch in south‐eastern Australia. Stable isotope analysis of 24 mothers and their litters revealed that isotope ratios of embryos were significantly different from their corresponding mothers and that the scale and direction of the difference varied within and across species. The range of...
Elasmobranchs are covered in scale‐like structures called dermal denticles, comprising dentine and enameloid. These structures vary across the body of an individual and between species, and are frequently shed and preserved in marine sediments. With a good understanding of denticle morphology, current and historical elasmobranch diversity and abundance might be assessed from sediment samples. Here, replicate samples of denticl...
Niche partitioning and individual specialisation in resources and space use of sympatric fur seals at their range marginNARA Subscribed
Ecological theory predicts niche partitioning between high-level predators living in sympatry as a mechanism to minimise the selective pressure of competition. Accordingly, male Australian fur seals Arctocephalus pusillus doriferus and New Zealand fur seals A. forsteri that live in sympatry should exhibit partitioning in their broad niches (in habitat and trophic dimensions) in order to coexist. However, at the northern end of...
Blue carbon is fast garnering international interest for its disproportionate contribution to global carbon stocks. However, our understanding of the size of these blue carbon stocks, as well as the provenance of carbon that is stored within them, is still poor. This is especially pertinent for many small-island nations that may have substantial blue carbon ecosystems that are poorly studied. Here, we present a preliminary ass...
Recreational fishing waste, produced from processing catches at shore‐based fish cleaning facilities and discarded into adjacent waters, is foraged by various aquatic species. However, the potential alterations to the diet of consumers of these resources are poorly studied. Smooth stingrays ( Bathytoshia brevicaudata ) are a large demersal mesopredatory ray species and common scavenger of recreational fishing discards around s...
Australian cownose rays ( Rhinoptera neglecta ) and whitespotted eagle rays ( Aetobatus ocellatus ) are large myliobatiform rays that co‐occur off temperate eastern Australia. Here, we performed stable‐isotope analyses (δ 13 C, δ 15 N and δ 34 S) on fin clips of both species to gain insights into their trophic interactions and isotopic niches, and assess the effect of preservation (ethanol‐stored versus frozen) on isotopic val...