206,520 research outputs found
Gill disease in barramundi (Lates calcarifer)
No full textDisease is a major impediment to world aquaculture, amplified by the increase of the intensity of aquaculture relieving pressure from over depleted wild stocks, but with intensity brings disease and particularly disease of the fragile gill organ, exposed directly to the water environment. There is little literature on barramundi biology and the various forms of culture impacting on health, particularly the gill and much research is required in gaining a further understanding of this popular eating fish.
The light microscope is a pivotal tool with cytology and histology mandatory in assessing gill health. The gill biopsy should be considered part of a clinical examination as the water medium surrounding the gill and on the gill contains often fragile organisms that would otherwise be lost in fixation for histology alone, but easily viewed with cytology. Barramundi are easily anaesthetised and recovered like many terrestrials and gill re-growth is rapid, healing within days. Biopsies should be viewed unstained with and without phase contrast and then stained and reviewed, recognizing some ectoparasites maybe lost with anaesthetic agents and stains. The sacrificing of the fish after a live gill biopsy is necessary with histology and microbiology our major tools for diagnostics, with no other non invasive methods readily available as for terrestrials. Every year many new water organisms related to aquaculture are described in the literature and the finding of novel and new organisms makes the veterinary examination of the live fish exciting yet imperative.
A major concern is the gill pathogens found in wild barramundi were similar to those found in culture. For example the prevalence of the parasite Henneguya a Myxosporidean was 90% in sea cages 60 km offshore from Darwin in the Bathurst Island river system and 66% for ponded fish with water drawn from the Darwin Elizabeth river, compared to 33% infected in the wild habitat of the Mary river system close to Darwin by road. However the bacterial disease Epitheliocystis had a prevalence of 66% in the sea cages and 18% of similarly sized fish in the Mary river system, yet nil found in the pond farm, but in this case sample numbers were restricted. Consequently the surveillance for new fish pathogens and monitoring for existing pathogens in the wild ecosystems and aquaculture facilities is necessary and must include the macro and micro flora and fauna surrounding such facilities as they are potentially affected from aquaculture waste streams. The sustainability of aquaculture in open water culture must be considered with great concern for many reasons, but disease by its nature could overwhelm a species and other aquatic life quickly disseminated in a dynamic water medium.
Freshwater culture of barramundi has problems with off flavour and disease, particularly recirculating aquaculture systems due to undercapitalization and possibly at this stage with existing type farms not suited for the culture of barramundi with one farm having all fish sampled diagnosed with systemic bacteraemia and gill Epitheliocystis. Commonly fish sampled from freshwater culture had suffered pathological changes to the gill, particularly hyperplasia indicating the fish are continually affected by issues of water quality and disease.
Pond culture appeared to control gill disease issues by affording lower stocking rates, high water exchanges from a river within metres, fallow and the flavour of the fish similar to wild catch or sea cage culture, when purged in brackish water. The decreased environmental and ecosystem risks, coupled with the pond farmer reporting good profits with a simple form of culture, also suitable for intensification is a success story for barramundi production for today and the future
R.M. Gill to Mary Edwards Walker
No full textCorrespondence from R. M. Gill to Mary Edwards Walker regarding two tickets to Walker's lecture that were sent to Gill. 1 letter
Gill, R L, NX53017
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387564Surname: GILL. Given Name(s) or Initials: R L. Military Service Number or Last Known Location: NX53017. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 2277.209827
Item: [2016.0049.19857] "Gill, R L, NX53017
Gill, R, VX56017
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387581Surname: GILL. Given Name(s) or Initials: R. Military Service Number or Last Known Location: VX56017. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 42499.209851
Item: [2016.0049.19874] "Gill, R, VX56017
Gill, R D, 417360
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387549Surname: GILL. Given Name(s) or Initials: R D. Military Service Number or Last Known Location: 417360. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 56915.209789
Item: [2016.0049.19842] "Gill, R D, 417360
Gill, R L, 406841
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387545Surname: GILL. Given Name(s) or Initials: R L. Military Service Number or Last Known Location: 406841. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 33020.209779
Item: [2016.0049.19838] "Gill, R L, 406841
Gill, R H, QX10305
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387569Surname: GILL. Given Name(s) or Initials: R H. Military Service Number or Last Known Location: QX10305. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 28057.209839
Item: [2016.0049.19862] "Gill, R H, QX10305
Gill, W R, 44293
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387543Surname: GILL. Given Name(s) or Initials: W R. Military Service Number or Last Known Location: 44293. Missing, Wounded and Prisoner of War Enquiry Card Index Number: SEA-3284.209774
Item: [2016.0049.19836] "Gill, W R, 44293
Gill, R T, 408367
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/387547Surname: GILL. Given Name(s) or Initials: R T. Military Service Number or Last Known Location: 408367. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 53395.209784
Item: [2016.0049.19840] "Gill, R T, 408367
A novel computerized real effort task based on sliders
No full textIn this note, we present a novel computerized real effort task based on moving sliders across a screen which overcomes many of the drawbacks of existing real effort tasks. The task was first developed and used by us in Gill and Prowse (forthcoming). We outline the design of our \slider task", describe its advantages compared to existing real effort tasks and provide a statistical analysis of the behavior of subjects undertaking the task. We believe that the task will prove valuable to researchers in designing future real effort experiments, and to this end we provide z-Tree code and guidance to assist researchers wishing to implement the slider task
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