https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54981 45 mm shell length) cockles, and report on the outcomes of preliminary trials of the gear for surveying Sydney Cockle. Efficiency trials showed that the gear captured and retained ∼95% of the cockles in the tow path, however efficiency decreased in compacted sediments (∼66%). Trial surveys captured cockles between 33 and 78 mm shell length, at densities as high as 186 individuals 100 m−2. The modified scallop dredge provides a robust and portable (∼10 kg weight) fishing gear for sampling estuarine soft sediment habitats from small vessels. Both the sampling gear, and the methodology presented here, are broadly applicable for surveying arcid cockles and other bivalve species from similar soft sediment habitats elsewhere.]]> Wed 27 Mar 2024 15:27:58 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39544 60 % of the biomass was required to obtain an accurate estimate of abundance for rarer species. The careful consideration of program objectives is important in optimising the sampling approach employed, as subsampling may not be appropriate for detection of rare species. The patterns presented here provide a quantitative basis to support sampling and sorting methodology for multispecies trawl samples, as well quantifying the implications of subsampling on the confidence in estimates of diversity or abundance.]]> Wed 27 Jul 2022 14:25:17 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46426 Wed 23 Nov 2022 09:51:18 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40502 Wed 13 Jul 2022 14:55:41 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31429 Chelidonichthys kumu, Grooved Gurnard Lepidotrigla modesta, and Roundsnout Gurnard Lepidotrigla mulhalli), were examined for the presence of such dietary niches. The species are either fishery-important (Red Gurnard) or provide prey (Grooved Gurnard and Roundsnout Gurnard) for fishery-important species (e.g., Platycephalidae and Zeidae). Based on stomach content analyses, all three gurnards were shown to be bottom-feeding carnivores that consumed mainly benthic crustaceans, particularly decapods and amphipods, with teleosts also being important in the diets of only the larger Red Gurnard. Nonmetric multidimensional scaling ordination and multivariate analyses based on volumetric contributions of different prey taxa to the stomach contents revealed significant differences in dietary composition among all three species, implying a partitioning of food resources. Size-related and temporal changes in dietary composition were each significant among the three gurnards, but there were no interactions between body size and time. Principal components analysis of head and mouth morphology demonstrated that mouth protrusiveness was the dominant morphological difference among species, which may in part account for the niche partitioning observed from the stomach content analysis. Given the important role of gurnards in benthic food webs, these relationships will improve the specification of ecosystem-based fisheries models and their ability to predict the effects of environmental and anthropogenic perturbations.]]> Wed 11 Apr 2018 14:09:53 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46025 Metapenaeus macleayi). These fisheries have experienced declining productivity over the last ten years and increasing occurrence of catchment-derived stressors in estuaries contribute to this problem. We evaluated the effect of pH 4–7.5 on School Prawn survival at two salinities (27 and 14.5), pH 5, 6 and 7.5 on the predation escape response (PER) speed at two salinities (27 and 14.5), and pH 4 and 7.5 on respiration rates. While mortality appeared to be greater in the high salinity treatment, there was no significant relationship between proportional survival and pH for either salinity treatment. Respiration was significantly slower under acidic conditions and the average PER was almost twice as fast at pH 7.5 compared to pH 5 (p < 0.05), indicating prawns may fall prey to predation more easily in acidic conditions. These findings confirm the hypothesised impacts of acidic water on penaeid prawns. Given that the conditions simulated in these experiments reflect those encountered in estuaries, acidic runoff may be contributing to bottlenecks for estuarine species and impacting fisheries productivity.]]> Wed 09 Nov 2022 15:45:04 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40212 Wed 06 Jul 2022 16:05:38 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52172 Wed 04 Oct 2023 10:55:46 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54490 Tue 27 Feb 2024 15:13:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47633 Tue 24 Jan 2023 14:24:13 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41927 Metapenaeus macleayi), through a series of experiments conducted under normal (pH 8) and acidic (pH 5) conditions. Experimental data were used to examine mortality. Also, histological examination of the gills and hepatopancreas was conducted to determine pathological consequences of exposure to these stressors. School Prawn did not experience mortality in response to acute exposure to Al under normal pH conditions, but mortality and tissue bioaccumulation of Al was greater under acidic conditions, suggesting an interactive effect of both stressors. Histology revealed sub-lethal effects of Al including structural abnormalities in the gills and hepatopancreas, and evidence of viral infection and immune response, particularly at lower pH and higher Al concentrations. These impacts may impede major vital functions such as respiration, osmotic regulation, metabolism and growth of juvenile School Prawn, which could contribute to productivity bottlenecks in degraded estuaries.]]> Tue 16 Aug 2022 11:19:40 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46339 Penaeus [Melicertus] plebejus; EKP, an important penaeid species harvested across eastern Australia) that are closed to trawling (on a permanent, and temporary basis) were evaluated using a combination of trawl and tag-recapture surveys. Over 1,250 EKP were tagged and released across the permanent and temporary trawl closure, and 15.4% of all tagged prawns were recaptured and reported by fishers in both New South Wales (33% of recaptures) and the adjacent jurisdiction of Queensland (67% of recaptures, up to 730 km from the point of tagging) during 7 months post-tagging. There were significant differences in prawn size and abundance across the permanent and temporary trawl closure areas with both depth and distance to the adjacent estuarine nursery explaining these patterns, but prawns generally exceeded the minimum size-at-first-capture estimated by relevant yield per recruit models before they left areas closed to trawling. While more prawns were captured in Queensland, recapture rates were far greater in New South Wales when standardised by relative effort. Patterns in these data highlight the broader considerations of spatial management in multi-jurisdictional fisheries.]]> Tue 15 Nov 2022 13:51:54 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43117 Tue 13 Sep 2022 14:25:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43115 Portunus armatus) is a widely distributed species that has been identified as a candidate for stock enhancement; however, the release strategy and ecological impact of releases have not yet been assessed. Here, we (1) quantify the bioenergetics of blue swimmer crab, (2) estimate consumption rates, and (3) develop these relationships in a stocking model to assess appropriate release densities and associated trophic impacts. Static respirometry was used to measure the resting metabolic rate (RMR) of blue swimmer crab at three temperatures (19, 24, and 29°C). RMR was found to increase with temperature (Q₁₀ = 2.32), and was 73% higher when crabs were at a premoult or moulting stage. Parameters derived from respirometry experiments were applied to estimate blue swimmer crab stocking density in a south-eastern Australian estuary, by adapting an existing production-based simulation model. The model estimated a median stocking density of ~1.2 crabs per 100 m². A sensitivity analysis showed that the growth rate was the most influential parameter in this model, showing the importance of this parameter when assessing stocking scenarios.]]> Tue 13 Sep 2022 14:23:56 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43086 n = 1,130 fish) and incorporated into a bioenergetic model (the “primary” model) that included diet variability (n = 144 prey sources) and ontogenetic changes in metabolism (1–7 year) to estimate lifetime consumption. We quantified error by building nine model scenarios that each incorporated different spatiotemporal diet data of four published studies. The model scenarios produced individual lifetime consumption estimates that were between 25% lower and 15% higher than the primary model (maximum difference was 53%, range 11.7–17.8 kg). When consumption (in mass) was held constant, differences in diet quality among models caused a several-fold range in growth rate (0.04–1.07 g day^–1). Our findings showcase the large uncertainty in consumption rate estimates due to diet diversity, and illustrate that caution is required when considering bioenergetic results among locations, times, and ontogeny.]]> Tue 13 Sep 2022 12:33:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37663 Tue 09 Mar 2021 18:06:03 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39925 Thu 30 Jun 2022 12:02:32 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50494 40% contribution) for three resident and five transient species, including polychaetes, blue swimmer crabs, toadfish, luderick, leatherjackets, oyster gobies, and stingarees. Benthic organic matter from the oyster reef was found to be a primary resource for 12 residents and four transient species, including crabs, shrimps, gastropods, and fish. Oyster reefs are key foraging grounds in the estuarine seascape, and their restoration will enhance fisheries productivity by broadening the trophic resource base and contribute to the estuarine energy transfer to higher trophic levels.]]> Thu 27 Jul 2023 10:15:39 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36709 4 saltmarsh plant Sporobolus virginicus had the greatest contribution to consumer diet among almost all sites and times (25–95%), though for prawns the presence of seagrass may be exerting some influence on this calculated contribution in the Clarence estuary. Particulate organic matter (POM; 30%) and fine benthic organic matter (FBOM; 39–41%) also contributed significantly to consumer diet. Mangroves and other C₃ sources generally had the lowest contribution to consumers (1–31%). While the exact contributions of each source are uncertain within our Bayesian framework, these results highlight the relatively large role of saltmarsh habitat as a contributor to fishery productivity, especially in estuaries with no seagrasses. Given the anthropogenic threats to saltmarsh habitat, there is potential for loss of fishery productivity with further loss of saltmarsh areal extent.]]> Thu 25 Jun 2020 16:03:41 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42124 Thu 25 Aug 2022 11:57:54 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38986 Thu 24 Mar 2022 16:39:31 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51216 Thu 24 Aug 2023 15:06:05 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40989 70% for salinity treatments other than the lowest salinity. Survival was 0% in the lowest salinity and all prawns had died within 3 days. Salinity did not appear to impact relative growth across the range of salinities examined. In contrast, relative somatic condition was greater at lower salinities and was negatively correlated with salinity, indicating lower salinities promote enhanced somatic condition in School Prawn. Total fatty acid concentration showed no relationship with salinity or somatic condition index. However, total fatty acid concentration did have a significant positive relationship with total amino acid concentration. Total amino acid concentration showed no linear relationship with salinity or somatic condition index. Quantitative profiling of individual fatty acids and amino acids showed some changes in response to salinity. Alpha-aminoadipic acid showed a significant positive relationship with salinity. These complex patterns suggest several shifts in cellular chemistry may occur throughout the salinity range investigated, potentially with metabolic consequences. These results highlight the complex responses of estuarine crustaceans to changes in salinity.]]> Thu 21 Jul 2022 09:34:25 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38738 Thu 20 Jan 2022 16:03:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54264 Thu 15 Feb 2024 14:31:17 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39933 Thu 14 Jul 2022 10:23:12 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31277 Penaeus [Melicertus] plebejus) and School Prawn (Metapenaeus macleayi) were studied for two years in the lower Hunter River estuary, on the temperate east coast of Australia. The higher salinity areas near the lower end of the estuary were most important for Eastern King Prawn, and marsh systems in the lower estuary were only important for the species where there was good connectivity with oceanic water. Areas along the estuary were important for juvenile School Prawn, especially marsh habitats, and relative abundance tended to increase with increasing distance along the estuary. Designation of effective juvenile habitat for School Prawn may have been affected by high fishing mortality in fished areas, but this requires further investigation. Salinity, depth, turbidity and distance along the estuary were all important indicators of prawn distribution. The implications of these patterns for current and future habitat rehabilitation in temperate Australia are discussed.]]> Sat 24 Mar 2018 08:44:32 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31392 Penaeus [Melicertus] plebejus), and the processes that contributed to this nursery role. Stable isotopes were used to assign prawns joining the adult stock to putative nursery habitat areas within the estuary. Emigrating prawns originated from only 11 of the 20 sites surveyed. Of these, 8 sites were designated as Effective Juvenile Habitat (EJH), and 5 sites designated as Nursery Habitat (NH). The contribution of individuals from different nursery areas to the adult stock was related to both the abundance of prawns within an area and the distance to the mouth of the estuary, and with the exception of 1 site all EJH and NH were located in the northern section of the estuary. Quantitative sampling in this area indicated that prawns were present at an average density of 165 ± 11 per 100 m², and density formed non-linear relationships with the distance to the mouth of the estuary, seagrass cover and temperature. Prawn size also formed non-linear relationships with prawn density and seagrass cover. Spatial patterns in abundance were consistent with wind-driven recruitment patterns, which in turn affected the nursery role of particular areas within the system. These findings have implications for targeted fishery restoration efforts for both Eastern King Prawn and other ocean spawned species in wave dominated estuaries where circulation is primarily wind-driven.]]> Sat 24 Mar 2018 08:43:01 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30702 Metapenaeus macleayi) and Mud Crab (Scylla serrata), two commercially important crustaceans in Australia. Perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA) were present in samples of both species collected following exposure under natural conditions in contaminated estuaries. Depuration was tested in uncontaminated water for 33 days. PFOA was present at levels close to LOR in both species, and was not detected after 4.5 h and 72 h in School Prawn and Mud Crab respectively. PFHxS was rapidly depurated by School Prawn, and had a depuration half-life of 5.7 h. PFOS was also depurated by School Prawn, with a depuration half-life of 158.5 h. PFHxS and PFOS concentrations were highly variable in Mud Crab both at the start, and during the depuration experiment, and a depuration model could not be fitted to the data. For School Prawn, depuration of total PFASs to the relevant screening value for protection of human health (9.1 μg kg^{− 1}) occurred within 7.1 h. Rapid depuration of PFASs in School Prawn indicates that human health risks associated with consumption may decrease as this species migrates away from the contamination source. Further research is required to better understand the relationships between contaminant load and life-history characteristics (such as growth, reproduction, and moult cycle) in Mud Crab, and future work should target broader time frames for depuration in this species.]]> Sat 24 Mar 2018 07:35:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42620 Mon 29 Aug 2022 08:32:13 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49576 Mon 22 May 2023 10:43:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:35377 Mon 22 Jul 2019 13:12:19 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48516 Mon 20 Mar 2023 17:00:06 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40787 Mon 18 Jul 2022 16:07:20 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46212 Penaeus (Melicertus) plebejus; EKP) as a case study, we examine how spatial and temporal factors can influence connectivity between a spatial management network designed to protect small prawns from capture by trawlers, and a multi-jurisdictional (Queensland [Qld] and New South Wales [NSW]) fishery. Over 7500 prawns were tagged across multiple years in three northern NSW spatial management areas, and 786 tagged prawns were recaptured across both jurisdictions. The majority of prawns tended to be recaptured from deeper waters adjacent to, or directly north of, the spatial management areas, but tagging location and release timing influenced recapture patterns. Cohorts tagged early in the growth season showed lower recapture rates, but were larger on average at recapture, and had migrated further. Prawns reached the fishery in the adjacent jurisdiction (Qld) within 54 days-post tagging, but for most cohorts the majority of recaptures were in NSW zones. Overall, there was good connectivity between all spatial management areas and the NSW fishery, and tagged prawns also reached the Qld spawning areas. This represents an optimal scenario for NSW fishers (who forgo capture of prawns within these spatial management areas): the prawns protected in the closure areas primarily contribute to harvest of larger sized prawns within NSW waters; and a portion of the protected prawns survive to reach the southern Queensland spawning grounds, which is the primary source of recruits for northern NSW nurseries. These findings are broadly relevant to defining the role and impact of established and proposed spatial management networks within penaeid fisheries.]]> Mon 14 Nov 2022 15:47:10 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38826 Mon 14 Feb 2022 15:24:37 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37463 2), and the average density across the wetland was 244 prawns per 100 m². All areas of the wetland (except the area closest to the wetland mouth) supported the full range of size classes, and multiple cohorts of prawns moved through the system during the sampling program. The asymmetry observed in the distribution of prawns across the wetland is likely to be due to a combination of water quality and inter-specific interactions. These results show that the recovering wetland is supporting a high abundance of School Prawn. Our estimates of recruitment for School Prawn will also be useful in gauging the potential increases in fisheries productivity arising from habitat repair in this, and other systems.]]> Mon 11 Jan 2021 16:09:20 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40434 500 μg L−1(acetamiprid). To assess uptake and elimination, shrimp were exposed to a fixed 5 μg L−1 water concentration for eight days (uptake) or four days of exposure followed by four days of depuration (elimination). Neonicotinoid water and tissue concentrations were measured by liquid chromatography-mass spectrometry following solid-phase extraction and QuEChER extraction respectively. The lower toxicity associated with acetamiprid could be associated with lower accumulation in the tissue, with concentrations remaining below 0.01 μg g−1. The activity of acetylcholinesterase, catalase and glutathione S-transferase in abdominal tissues was determined by spectrophotometric assay, with significant sublethal effects detected for all four neonicotinoids. Depuration reduced the tissue concentration of the active ingredient and reduced the activity of oxidative stress enzymes. Given acetamiprid showed no acute toxicity and reduced impact on the enzymatic activity of P. monodon, it may be an appropriate alternative to other neonicotinoids in shrimp producing areas.]]> Mon 08 Aug 2022 13:25:28 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40554 Metapenaeus macleayi (School Prawn) and Penaeus plebejus (Eastern King Prawn) are two commercially and recreationally important species in New South Wales that utilise estuarine nurseries throughout their life history. In this study, stable isotopes of carbon, nitrogen and sulfur were used to determine the proportional contribution of primary producers to prawn nutrition in Brisbane Water (NSW). Both the saltmarsh grass Sporobolus virginicus and seagrass Zostera muelleri were found to support a high trophic contribution to prawns (up to 53% and 40%, respectively). The contributions of other primary producers such as mangroves, fine benthic organic matter (FBOM) and C3 saltmarsh plants were generally found to be much lower (0.7-15%). Such findings are generally consistent with patterns observed in other south-east Australian estuaries, however such a dominant role of saltmarsh in the presence of seagrass is a novel finding. These results highlight linkages between habitats of conservation concern and highly valuable fisheries species, and the benefit of using sulfur as an additional marker in Bayesian mixing models examining estuarine food webs.]]> Fri 22 Jul 2022 15:25:21 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37144 Fri 21 Aug 2020 12:35:43 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51083 Fri 18 Aug 2023 09:38:16 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:54826 Fri 15 Mar 2024 11:46:13 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41757 Fri 12 Aug 2022 11:42:23 AEST ]]>