Browsing by Author "Fry, B"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Muscle and carapace tissue–diet isotope discrimination factors for the freshwater crayfish Cherax destructor
    (CSIRO Publishing, 2017-09-08) Mazumder, D; Johansen, MP; Fry, B; Davis, E
    This study examined a range of diets and two tissue types (muscle and carapace, representing protein and chitin biochemistry respectively) of Cherax destructor (Clark, 1936) to allow more accurate use of isotope data in trophic source estimates. The resulting Δ13Ctissue–diet and Δ15Ntissue–diet discrimination factors of muscle and carapace tissues showed significant differences among diets. For muscle, Δ13Ctissue–diet was higher (2.11–2.33‰) when C. destructor was fed with lamb, turkey and mixed animal and plant-based diets, 1.27–1.96‰ when C. destructor was fed with beef and kangaroo diets and negative (–1.36‰) when C. destructor was fed with an aquatic meat (tuna) diet. The Δ15Ntissue–diet discrimination factors were lower for muscle when C. destructor was fed aquatic meat (0.12‰) and mixed plant–animal diets (1.67‰), but higher for terrestrial meat diets (2.79–3.74‰). The Δ13Ctissue–diet for carapace followed similar patterns to that of muscle, but Δ15Ntissue–diet values were lower for carapace than muscle. Strong correlations were observed between muscle and carapace for δ13C (r = 0.96, P < 0.0001) and δ15N (r = 0.82, P < 0.0012) across the six diets evaluated, indicating that carapace can be used as a non-lethal alternative to muscle during field sampling. © CSIRO 2017
  • Thumbnail Image
    Item
    Radiocarbon as a novel tracer of extra-Antarctic feeding in Southern Hemisphere humpback whales
    (Springer Nature Limited, 2017-06-29) Eisenmann, P; Fry, B; Mazumder, D; Jacobensen, GE; Holyoake, CS; Coughran, D; Bengtson Nash, S
    Bulk stable isotope analysis provides information regarding food web interactions, and has been applied to several cetacean species for the study of migration ecology. One limitation in bulk stable isotope analysis arises when a species, such as Southern hemisphere humpback whales, utilises geographically distinct food webs with differing isotopic baselines. Migrations to areas with different baselines can result in isotopic changes that mimic changes in feeding relations, leading to ambiguous food web interpretations. Here, we demonstrate the novel application of radiocarbon measurement for the resolution of such ambiguities. Radiocarbon was measured in baleen plates from humpback whales stranded in Australia between 2007 and 2013, and in skin samples collected in Australia and Antarctica from stranded and free-ranging animals. Radiocarbon measurements showed lower values for Southern Ocean feeding than for extra-Antarctic feeding in Australian waters. While the whales mostly relied on Antarctic-derived energy stores during their annual migration, there was some evidence of feeding within temperate zone waters in some individuals. This work, to our knowledge, provides the first definitive biochemical evidence for supplementary feeding by southern hemisphere humpback whales within temperate waters during migration. Further, the work contributes a powerful new tool (radiocarbon) for tracing source regions and geographical feeding. © The Authors. Creative Commons Attribution 4.0 International Licence
  • No Thumbnail Available
    Item
    Uptake and accumulation of cadmium, manganese and zinc by fisheries species: trophic differences in sensitivity to environmental metal accumulation
    (Elsevier, 2019-11-10) O'Mara, K; Adams, MS; Burford, MA; Fry, B; Cresswell, T
    Fishery targeted species living in estuaries face multiple anthropogenic pressures including habitat contamination. However, trace metal concentrations in aquatic organisms can be highly variable, making it difficult to interpret accumulation responses. Understanding sources for metal accumulation in these organisms and their biokinetics is important for management of local fisheries and ensuring safety and quality of consumed seafood, particularly in urbanised areas. In this study, we exposed Australian sand clams, school prawns and sand whiting to a combination of cadmium (Cd), manganese (Mn) and zinc (Zn) radioisotopes 1) dissolved in seawater, 2) adsorbed to suspended sediment particles and 3) in radiolabelled food. Sand clams were sensitive to Cd, Mn and Zn uptake and accumulation from all sources because of their filter feeding physiology. Mean Cd and Zn assimilation efficiencies (AE) were higher in clams fed benthic diatoms (51, 43, 63% for Cd, Mn and Zn, respectively) than clams fed an algal flagellate species (22, 32, 33% for Cd, Mn and Zn, respectively). Metal uptake by prawns from seawater was low, whereas assimilation from diet was high (67, 59, 64% mean AEs from Cd, Mn and Zn, respectively). Sand whiting did not accumulate metals from seawater, even after concentrations were increased. Assimilation from diet (labelled prawns) was also low for sand whiting, particularly for Cd and Zn (11, 26, 14% mean AEs from Cd, Mn and Zn, respectively). These results may help explain the persistence of sand whiting in contaminated estuaries. Suspended sediment exposures showed that prawns and fish are less likely than clams to be negatively affected by disturbance events such as floods, which can bring metals into estuaries. The findings of this study have implications for fisheries management, both for protection and remediation of important habitats, and to ensure safe standards for seafood consumption by humans. © 2019 Elsevier B.V