ORCID Profile
0000-0002-1834-6945
Current Organisation
University of Tasmania
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Publisher: Elsevier BV
Date: 2021
DOI: 10.2139/SSRN.3784895
Publisher: The Royal Society
Date: 24-07-2019
Abstract: The effects of anthropogenic aquatic noise on marine invertebrates are poorly understood. We investigated the impact of seismic surveys on the righting reflex and statocyst morphology of the palinurid rock lobster, Jasus edwardsii , using field-based exposure to air gun signals. Following exposure equivalent to a full-scale commercial assay passing within 100–500 m, lobsters showed impaired righting and significant damage to the sensory hairs of the statocyst. Reflex impairment and statocyst damage persisted over the course of the experiments—up to 365 days post-exposure and did not improved following moulting. These results indicate that exposure to air gun signals caused morphological damage to the statocyst of rock lobsters, which can in turn impair complex reflexes. This damage and impairment adds further evidence that anthropogenic aquatic noise has the potential to harm invertebrates, necessitating a better understanding of possible ecological and economic impacts.
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/MF07026
Abstract: Development of the pharyngeal dentition of two herbivorous halfbeaks, Hyporh hus regularis ardelio (Whitley, 1931) and Arrh hus sclerolepis krefftii (Steindachner, 1867), was examined quantitatively to assess features that might confer their ability to shift their diet from animal to plant material. Toothed area, tooth number, maximum tooth diameter and tooth wear area in both pharyngeal tooth pads of both taxa increased with ontogeny, whereas tooth density decreased. Comparing in iduals of the two taxa at similar standard lengths indicated that A. sclerolepis krefftii showed hypertrophy of the majority of pharyngeal characters in relation to H. regularis ardelio of a similar standard length. That A. sclerolepis krefftii is more developmentally advanced than H. regularis ardelio in almost all dentigerous characters studied indicates that pharyngeal development may allow the former to commence herbivory at a smaller standard length than the latter species. The evolutionary and ecological implications of these findings are discussed in the context of a group of fishes that is overexploited worldwide.
Publisher: Springer Science and Business Media LLC
Date: 07-03-2014
DOI: 10.1007/S00360-014-0813-4
Abstract: We explored the integrated role of dietary specialization and feeding periodicity on the response of the gastrointestinal tract of teleosts fishes to short-term (7-10 days) fasting and refeeding. Fasted and fed herbivorous grass carp (Ctenopharyngodon idella), omnivorous channel catfish (Ictalurus punctatus), and carnivorous largemouth bass (Micropterus salmoides) were compared for digestive organ masses, intestinal morphology, gastrointestinal pH, and the specific activities and total intestinal capacities of the intestinal hydrolases aminopeptidase (APN) and maltase and intestinal nutrient transporters. All three species experience intestinal hypertrophy with feeding as noted by significant increases in enterocyte dimensions. Of the three, only I. punctatus experienced a postprandial increase in intestinal length, and only C. idella experienced significant modulation of intestinal microvillus length. Feeding resulted in acidification of the stomachs of I. punctatus and M. salmoides. Predicted to exhibit a relatively modest set of postprandial responses because of their more frequent feeding habits, C. idella only experienced increases in APN and maltase activity with feeding and no significant regulation of nutrient uptake. Significant regulation of hydrolase activities and nutrient uptake were exhibited by I. punctatus and M. salmoides, with I. punctatus experiencing the most comprehensive set of responses. As predicted by food habits, there was an interspecific gradient in intestinal length and glucose uptake extending from longer intestines and greater glucose uptake for the herbivorous C. idella, intermediate lengths and glucose uptake for the omnivorous I. punctatus, and shorter intestines and reduced glucose uptake for the carnivorous M. salmoides. Among teleosts fishes, short episodes of fasting lead to significant alterations in intestinal form and function that are rapidly restored with feeding.
Publisher: Springer Science and Business Media LLC
Date: 22-06-2017
Abstract: Zooplankton underpin the health and productivity of global marine ecosystems. Here we present evidence that suggests seismic surveys cause significant mortality to zooplankton populations. Seismic surveys are used extensively to explore for petroleum resources using intense, low-frequency, acoustic impulse signals. Experimental air gun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar (~3-4 dB drop within 15-30 min) and net tows (median 64% decrease within 1 h), and caused a two- to threefold increase in dead adult and larval zooplankton. Impacts were observed out to the maximum 1.2 km range s led, which was more than two orders of magnitude greater than the previously assumed impact range of 10 m. Although no adult krill were present, all larval krill were killed after air gun passage. There is a significant and unacknowledged potential for ocean ecosystem function and productivity to be negatively impacted by present seismic technology.
Publisher: Wiley
Date: 16-09-2022
DOI: 10.1002/AFF2.64
Abstract: Palinurid rock (or spiny) lobsters constitute valuable seafood fisheries around the world. Post‐harvest mortality can have a substantial economic impact on the value of these fisheries and damage the brand identity of an otherwise fungible commodity. In this study, sudden, large‐scale mortalities in the Australian Rock Lobster industry were investigated through comprehensive haemolymph biochemistry panels, measurements of immune status and nutritional condition. A cohort of lobsters ( n = 25) was s led over a 4‐week period at a commercial processing facility, with the final s le occurring during a mortality event. A comparison of 22 biochemical parameters, including electrolytes, minerals, ions, metabolites and enzymes, showed a notable disruption in osmoregulation, protein content and enzymes during weeks 3 and 4 of the study. Haemocyte counts showed a decline in circulating haemocytes by the time of the mortality event along with a shift in the proportion of hyalinocytes to granulocytes favouring the former. The condition index was variable over the s ling schedule, possibly linked to observed incidences of cannibalism, with no evidence of an overall low condition that would explain mortalities. The lobsters s led in this study did not show any consistent or progressive changes in biochemistry that may indicate a pathogen or disease as a causative agent. Rather, analysis of the water quality within the facility suggested that mortality was due to sub‐optimal water quality characterized by a combination of two factors, a substantial decrease in the pH and potential nitrogen toxicity, that caused a physiological response comprised of an ion imbalance, altered enzyme activity and, ultimately, mortality. These results offer a comprehensive characterization of the impact of unexplained morbidity on the biochemistry and physiology of lobsters, illustrate the harm of sub‐optimal aquaculture practices and highlight the need for a better understanding of aquaculture practices and their effects on economically important seafood industries.
Publisher: Elsevier BV
Date: 07-2007
DOI: 10.1016/J.GIE.2006.12.056
Abstract: The growing demand for endoscopy associated with colorectal cancer screening has resulted in busier endoscopy units and an increase in the practice of open-access endoscopy, in which patients are referred for procedures without prior consultation by the gastroenterologist, all of which may result in less-informed patients. We sought to determine whether providing patients with a written copy of their standard endoscopy report at the conclusion of their procedure enhanced recall of the findings and recommendations. Eighty consecutive outpatients who presented to 3 endoscopists were randomized to receive the results of their upper or lower endoscopy via standard verbal report (VR) or by standard VR followed by receipt of a computer-generated endoscopy report (VR+WR) from the Olympus ImageManager report generator. The endoscopist communicated the VR after a standard postprocedure recovery period of 30 to 60 minutes and routinely discussed all findings and recommendations as mentioned in the WR. The endoscopist was blinded as to whether the patient subsequently received the WR. Recall of the endoscopic procedure was assessed by using a piloted 11-question survey instrument to be filled out 3 days after the procedure. Results were calculated by using the Fisher exact and Wilcoxon rank sum tests. Referral for endoscopy from University of Chicago physicians. Seventy-eight of 80 patients (98%) approached about the study agreed to participate. The response rate was 77%. Patients in the VR+WR group overall had a greater composite score than patients in the VR group (8.9/10 vs 7.7/10, P<.01). Patients in the VR+WR group were also significantly more likely to recall the recommendations for therapy or follow-up (72% vs 42%, P<.01) and the name of the endoscopist (97% vs 74%, P<.05). Patients with an education beyond the 10th-grade level were not formally accessed in this study. Because of this, we could not evaluate whether differences in educational attainment affected patient understanding of endoscopy procedure details and findings. A computer-generated endoscopy report (WR) significantly improved patient recall of endoscopic procedure information compared with a VR alone. Despite this, patients were unable to recall 28% of recommendations. Additional study to determine if such enhanced physician-patient communication improves patient satisfaction or follow-up, and whether more specific patient-directed results further improve recall needs to occur.
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.ENVPOL.2022.119699
Abstract: Anthropogenic aquatic noise is recognised as an environmental pollutant with the potential to negatively affect marine organisms. Seismic surveys, used to explore subseafloor oil reserves, are a common source of aquatic noise that have garnered attention due to their intense low frequency inputs and their frequent spatial overlap with coastal fisheries. Commercially important Southern Rock Lobster (Jasus edwardsii) adults have previously shown sensitivity to signals from a single seismic air gun. Here, the sensitivity of J. edwardsii juveniles and puerulus to the signals of a full-scale seismic survey were evaluated to determine if early developmental stages were affected similarly to adults, and the range of impact. To quantify impact, lobster mortality rates, dorsoventral righting reflex and progression through moult cycle were evaluated following exposure. Exposure did not result in mortality in either developmental stage, however, air gun signals caused righting impairment to at least 500 m in lobsters s led immediately following exposure, as had previously been reported in adults with corresponding sensory system damage following exposure. Impairment resulting from close range (0 m) exposure appeared to be persistent, as previously reported in adults, whereas juveniles exposed at a more distant range (500 m) showed recovery, indicating that exposure at a range of 500 m may not cause lasting impairment to righting. Intermoult duration was (time between moults) significantly increased in juveniles exposed at 0 m from the source, indicating the potential for slowed development, growth, and physiological stress. These results demonstrate that exposure to seismic air gun signals have the potential to negatively impact early life history stages of Southern Rock Lobsters. The similarity of both the impacts and the sound exposure levels observed here compared to previous exposure using a single air gun offer validation for the approach, which opens the potential for accessible field-based experimental work into the impact of seismic surveys on marine invertebrates.
Publisher: Wiley
Date: 03-2009
DOI: 10.1002/JMOR.10696
Abstract: To assess how tooth microstructure and composition might facilitate the pharyngeal mill mechanism of halfbeaks, apatite structure and iron content were determined by scanning electron microscopy and energy dispersive X-ray analysis for Hyporh hus regularis ardelio, Arrh hus sclerolepis krefftii, and Hemir hus robustus. Iron was present in developing teeth and was concentrated along the shearing edge of spatulate incisiform teeth, which dominate the occlusive wear zone in all three species. A model based on tooth structure and wear rate is proposed to explain how halfbeaks maintain a fully functional occlusion zone throughout growth and consequent tooth addition and replacement. Replacement teeth erupt and wear rapidly so that a constant occlusion plane is always present. Iron within the tooth tissue reduces the wear rate of the cutting edge while simultaneously maintaining its sharpness and efficiency.
Publisher: Cold Spring Harbor Laboratory
Date: 15-01-2021
DOI: 10.1101/2021.01.13.426456
Abstract: The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems: mouse and zebrafish. In both models Cavin4 localized to T-tubules and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein, Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca 2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.
Publisher: The Company of Biologists
Date: 10-2006
DOI: 10.1242/JEB.02449
Abstract: A common feature of animal locomotion is its organization into gaits with distinct patterns of movement and propulsor use for specific speeds. In terrestrial vertebrates, limb gaits have been extensively studied in erse taxa and gait transitions have been shown to provide efficient locomotion across a wide range of speeds. In contrast, examination of gaits in fishes has focused on axial gaits and the transition between synchronous paired fin locomotion and axial propulsion. Because many fishes use their pectoral fins as their primary propulsors, we aimed to examine more broadly the use of pectoral fin gaits in locomotion. We used juvenile reef fishes in these experiments because their swimming could be recorded readily across a wide range of Reynolds numbers, which we thought would promote gait ersity. Based on previous work in larval fishes, we hypothesized that juveniles have alternating pectoral fin movements rather than the synchronous, or in-phase,coordination pattern of adults. In flow tank swim studies, we found that juvenile sapphire damselfish Pomacentrus pavo used two fin gaits during steady swimming. Below approximately 3 BL s-1, P. pavo primarily swam with alternating fin strokes 180° out of phase with one another. At speeds in the range of 3-4 BLs-1, they performed a gait transition to synchronous fin coordination. Between approximately 4 and 8 BL s-1, P. pavo primarily beat their fins synchronously. At around 8 BLs-1 there was another gait transition to body-caudal fin swimming,in which the pectoral fins were tucked against the body. We suggest that the transition from alternating to synchronous fin coordination occurs due to mechanical limits of gait performance rather than to energy efficiency,stability or transitions in hydrodynamic regime. To determine whether this gait transition was species-specific, we surveyed pectoral fin locomotion in juveniles from 11 species in three reef fish families (Pomacentridae, Labridae and Scaridae). We found that this gait transition occurred in every species examined, suggesting that it may be a common behavior of juvenile reef fishes. Greater inclusion of early life history stages in the study of fin-based locomotion should significantly enhance and inform the growing body of work on these behaviors.
Publisher: Rockefeller University Press
Date: 11-10-2021
Abstract: The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems, mouse and zebrafish. In both models, Cavin4 localized to T-tubules, and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule–associated BAR domain protein Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Wiley
Date: 10-2009
DOI: 10.1002/JMOR.10745
Abstract: Belonidae are unusual in that they are carnivorous but lack a stomach and have a straight, short gut. To develop a functional morphological model for this unusual system the gut contents and alimentary tract morphology of Tylosurus gavialoides and Strongylura leiura ferox were investigated. The posterior orientation of the majority of the pharyngeal teeth supports the swallowing of whole large prey, but not their mastication. Mucogenic cells are abundant in the mucosa lining, particularly the esophagus, and their secretions are likely to protect the gut lining from damage while lubricating passage of the prey. Esophagus, anterior intestine, posterior intestine, and rectum all have highly reticulate mucosae. The anterior three gut sections are distensible to accommodate the passage of prey. However, following ingestion large prey are passed to the highly distensible posterior intestine where they rest head first against the ileorectal valve. Alimentary pH ranges from neutral to weakly acidic. Fish prey is digested head first with the head being largely digested while the remainder of the body is still intact. The nondistensibility of the rectum and the small aperture provided by the ileorectal valve suggest the products of intestinal digestion are either small particulates or fluids that pass into rectum where they are absorbed.
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.CBPB.2010.09.010
Abstract: Most young fishes lack the ability to function as herbivores, which has been attributed to two aspects of the digestive system: elevated nitrogen demand and a critical gut capacity. We compared the digestive morphology and biochemistry of two size classes of the marine herbivore Hyporh hus regularis ardelio, pre-ontogenetic trophic shift (pre-OTS, 100mm), to determine what limits the onset of herbivory and how their digestive processes fit with current models of digestion. Two gut-somatic indices comparing gut length to body length (relative gut length) and body mass (Zihler's Index) demonstrated a significant decrease (RGL 0.59→0.49, P<0.01 ZI 3.24→2.44, P<0.01) in gut length relative to body size. There was little difference in enzyme activity between the two classes, with juveniles showing similar levels of carbohydrase and lipase and less protease compared with adults, indicating that juveniles did not preferentially target nitrogen and were as capable of digesting an herbivorous diet. These findings suggest that herbivory in this fish is not limited by the function of the post-oesophageal digestive tract, but rather the ability of the pharyngeal mill to mechanically process plants. Our findings offer partial support for the current model of stomachless digestion, indicating that further refinement may be necessary.
Publisher: Springer Science and Business Media LLC
Date: 07-01-2011
DOI: 10.1007/S00360-010-0546-Y
Abstract: The lack of a stomach is not uncommon amongst teleost fishes, yet our understanding of this reductive specialisation is lacking. The absence of a stomach does not restrict trophic preference, resulting in fishes with very similar alimentary morphology capable of digesting differing diets. We examined the digestive biochemistry of four beloniform fishes: two herbivorous halfbeaks (Hemir hidae) and two carnivorous needlefish (Belonidae) to determine how these fishes digest their respective diets with their simple, short gut. We found that although the halfbeaks showed significantly greater α-amylase activity than that of the needlefish (P < 0.01), trypsin, lipase, aminopeptidase and maltase activity were not substantially different between the two families. We also found that habitat (freshwater vs. marine) appears to play a significant role in digestive capability, as the two freshwater taxa and the two marine taxa were significantly different (ANOSIM dietary Gobal R = 0.544, P = 0.001, habitat Global R = 0.437, P = 0.001), despite their phyletic and dietary similarities. Our findings offer partial support for the adaptive modulation hypothesis, support the Plug-Flow Reactor model of digestion in herbivorous halfbeaks and also support the compartmental model of digestion but suggest that another model is required to describe stomachless carnivorous needlefish.
Publisher: Wiley
Date: 28-10-2015
DOI: 10.1111/JFB.12799
Abstract: Needlefishes (Beloniformes) were observed employing a range of stalking and attacking behaviours to attack schools of bait fishes ranging from the use of tactics common to predatory fishes to a novel behaviour: the use of leaping, aerial attacks. These aerial attacks are suggested to serve two purposes: to extend the attack range of the needlefishes and to reduce their prey's potential for evasion. Furthermore, a third purpose is hypothesized that the needlefishes are taking advantage of Snell's Window, an optical effect which may mask their approach to their prey.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.FSI.2019.03.043
Abstract: Lobsters are fished world-wide due to their status as a high value, luxury seafood. A large proportion of the product is sold via live export, with lobsters subject to a range of stressors during holding post-capture. Improving the current understanding of the immune response to these stressors assists in improving efficiency and reducing loss in the chain between capture and consumption. In this study, the immune status of four treatment groups of Southern Rock Lobster (Jasus edwardsii) were studied: controls recently landed from a fishing boat, lobsters displaying advanced shell necrosis, lobsters in an unexplained moribund state and lobsters held in a processing facility for 10 weeks in standard conditions (i.e. high density, fasted). A total of 15 immune parameters and 19 haemolymph biochemical parameters were assayed. Phenoloxidase activity was only sporadically observed in haemocyte lysate and was consistently observed at a low level in the plasma with no difference between treatments for either. Haemocyte lysate prophenoloxidase activity was detected in most in iduals, with no differences found between treatments. Prophenoloxidase in the plasma showed the highest level of activity, with the shell necrosis treatment demonstrating an elevated activity level relative to the other three treatments. Cell viability was not affected in any treatment. Lobsters with shell necrosis had a reduced capacity for phagocytosis, a significantly higher total haemocyte count, fewer hyalinocytes and more granulocytes and semigranulocytes. Fasted lobsters showed an opposite shift, with significantly more hyalinocytes compared to the other treatments and very few granulocytes and semigranulocytes. The balance of a range electrolytes, minerals metabolites and enzymes were affected in shell necrosis and fasted treatments, raising them as potential markers for immunocompromised lobsters. Multivariate analysis of all assayed parameters showed that all in iduals in the necrosis treatment showed a similar, distinct immune response and that the fasted treatment, along with one control and one moribund in idual, showed a separate intermediate response. The remainder of the control and moribund lobsters demonstrated a distinct "non-response" in comparison. These results offer a characterisation of the physiological response to common challenges during post-capture holding of rock lobsters, demonstrating the differential response to pathogenic bacterial infection, long term fasting, non-specific moribundity and the stress of capture and transport.
No related grants have been discovered for Ryan Day.