https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28245 Wed 11 Apr 2018 15:05:52 AEST ]]> https://ogma.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://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47407 Saccostrea glomerata is one measure addressing these problems by producing fast‐growing, disease‐resistant oysters. Farmers report that selected oysters have different growth characteristics than their wild counterparts using conventional grow‐out methods. This study investigated how different grow‐out methods influence commercially valuable oyster characteristics including shell length, shape, surface growth deformities and meat condition. In June 2015, selectively bred S. glomerata spat were deployed in two estuaries (Hawkesbury River and Georges River) in NSW, Australia, using three grow‐out methods (fixed trays, Stanway cylinders and floating baskets). In November 2015, oysters were transferred among grow‐out methods to test for the effects of changing grow‐out methods on oyster growth patterns. Oysters transferred from baskets to cylinders and from trays to cylinders had, on average, deeper and wider shells, a higher meat condition and fewer shell surface deformities than oysters in other grow‐out method combinations. However, these oysters were smaller than oysters not grown in cylinders. While there were some differences in growth patterns between the estuaries, overall it was the grow‐out methods that most influenced oyster characteristics. This was attributed to differences in the amount and magnitude of movement oysters experienced in the grow‐out methods, as recorded by motion sensors. This study demonstrates how grow‐out methods can be managed to achieve desired growth trajectories and therefore improve marketability among selective bred S. glomerata.]]> Tue 17 Jan 2023 15:54:37 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:54208 Tue 13 Feb 2024 11:52:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45035 Thu 27 Oct 2022 13:46:27 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35989 Thu 23 Jan 2020 11:40:14 AEDT ]]> https://ogma.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://ogma.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://ogma.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://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19136 Sat 24 Mar 2018 07:55:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25333 Sat 24 Mar 2018 07:30:24 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40787 Mon 18 Jul 2022 16:07:20 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37668 Dendronephthya australis, with its limited distribution along the central New South Wales (NSW) coastline, forms a habitat within the benthic estuarine environment that supports commercially significant and protected marine species. However, the functional role of the soft coral within this system is unknown. Organisms from primary producers through to secondary consumers were sampled from soft coral and sponge habitats inside the Port Stephens estuary, NSW, Australia in 2014. A food web model of the benthic habitat, created using stable isotopes of carbon and nitrogen, was used to describe the functional role of the soft coral in comparison to sponges, another important habitat for commercially significant and protected marine species. Primary consumers accessed a range of benthic and pelagic energy sources; however, secondary consumers were almost entirely dependent on pelagic energy sources. Soft coral and sponges accessed different primary sources for their energy requirements. There was no evidence that D. australis was used as a direct food source by consumers other than nudibranchs. In contrast, sponges were trophically linked with secondary consumers and are likely to play a direct role in pelagic energy transfer. Amphipods collected from the branches of D. australis were identified as major prey components in the diet of protected syngnathids, suggesting that while the soft coral functions as critical habitat, it is indirectly linked to higher trophic levels.]]> Fri 25 Jun 2021 13:34:15 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41757 Fri 12 Aug 2022 11:42:23 AEST ]]>