Author: TheFishVet - Richmond's School of Fish

FYI.

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Yours sincerely,

Dr Richmond Loh
BSc, BVMS, MPhil (Vet Path), MANZCVS (Aquatics), MANZCVS (Pathobiology), DipPM.
Veterinarian | Adjunct Senior Lecturer Murdoch University | WAVMA President-Elect |
Secretary Aquatic Animal Health Chapter – Australian and New Zealand College of Veterinary Scientists (ANZCVS)
The Fish Vet, Perth, Western Australia, AUSTRALIA.

This article was sourced from http://oceanacidification.wordpress.com/2013/02/12/ecological-aspects-of-marine-vibrio-bacteria-exploring-relationships-to-other-organisms-and-a-changing-environment/

Ecological aspects of marine Vibrio bacteria – exploring relationships to other organisms and a changing environment
Posted by Lina Hansson

Heterotrophic bacteria of the genus Vibrio are indigenous in the marine environment although environmental cues regulate their growth and distribution. The attention brought to this genus is due to its many species/strains that are pathogenic to humans and other organisms. Vibrio abundances are strongly coupled to water temperature and salinity but abundance dynamics occur even where these hydrographical parameters are stable. In this thesis, I have studied Vibrio dynamics in relation to other organisms such as phytoplankton (papers I, II and III) and a bivalve host-organism (paper IV) in a changing environment where increasing temperature (paper III) and ocean acidification (paper IV) may influence survival and proliferation of these bacteria. In particular paper I showed that in a tropical coastal area, where the water temperature and salinity were stable across seasons, abundances of Vibrio were tightly coupled to phytoplankton biomass and community composition. A diatom bloom during December seemed to support high numbers of vibrios in waters with otherwise low levels of dissolved organic carbon. Paper II further supports that some phytoplankton can favor Vibrio growth while others seem to have a negative influence on Vibrio abundances. For instance, Skeletonema tropicum, a common diatom in Indian coastal waters, easily eradicated Vibrio parahaemolyticus from sea water in our experiments. In temperate marine areas culturable Vibrio predominantly occurs in the water column during the warmer months. Sediments are suggested to be potential reservoirs when conditions in the water-column are harsh. Accordingly, in paper III we showed that cold-water sediments from geographically separate areas in a boreal region of Scandinavia all contained relative high abundances of total Vibrio spp. and that all sediments also included culturable Vibrio. In agreement with paper I, the fresh input of organic material from phytoplankton blooms, for which chlorophyll a was used as a proxy, seemed to positively influence Vibrio abundances also in the sediments (paper III). Therefore, the pelagic-benthic coupling which can supply the sediments with biomass from the primary production could influence the abundance of Vibrio spp. Increasing temperature had variable influence on sediment-associated Vibrio abundance, with a significant increase in abundances in sediments originating from one area when the temperature reached over 21°C and a generally negative influence of increasing temperature on abundances in sediments originating from another area (paper III). This suggests that the sediments contained different Vibrio communities with varying temperature tolerance traits. Rising levels of carbon dioxide in the atmosphere does not only lead to higher water temperature through the green house effect, but also to acidification of the oceans. Paper IV illustrated how a common bivalve pathogen, Vibrio tubiashii, can be favored in the interaction with a calcifying bivalve host, Mytilus edulis, when this host-pathogen combination was exposed to levels of ocean acidification projected to occur by the end of the 21st century. Thus, global environmental changes may enhance the probability of Vibrio infections in higher organisms.

Asplund M. E., 2013. Ecological aspects of marine Vibrio bacteria – Exploring relationships to other organisms and a changing environment. PhD thesis, University of Gothenburg. Thesis.

There are many drugs and chemicals that enter our waterways that can exert effects on aquatic life even at levels beyond detectable limits by even the most sophisticated of equipment. Immunosuppression, behavioural changes and endocrine disruption are some effects in aquatic animal life that have been reported in the literature due to residues from agrichemicals and human medications. Even algal growth can be affected! There is still a lot of controversy around these findings due to the complexity of the pathogenesis, however, the is evidence out there. There’s no denying this in Sweden, already work is underway to curb such effects by way of advanced techniques for wastewater treatment.

Read more below…

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Yours sincerely,

Dr Richmond Loh
BSc, BVMS, MPhil (Vet Path), MANZCVS (Aquatics), MANZCVS (Pathobiology), DipPM.
Veterinarian | Adjunct Senior Lecturer Murdoch University | WAVMA President-Elect |
Secretary Aquatic Animal Health Chapter – Australian and New Zealand College of Veterinary Scientists (ANZCVS)
The Fish Vet, Perth, Western Australia, AUSTRALIA.

Shared by my friend, Dr Rob Ossiboff:

“Here is an interesting story on antibiotic resistant bacteria in aquarium fish; one of the major suspected drivers is the (mis)use of prophylactic antibiotics by hobbyists. I was amazed at how many types of antibiotics can be acquired over the counter by hobbyists. One of your jobs as aquatic vets will be to educate about the dangers of such use.”

http://www.smartplanet.com/blog/report/fancy-fish-could-harbor-dangerous-bacteria/1226

(be sure to check www.timeanddate.com/worldclock/converter.html for your local time)

DON’T MISS OUT AND REGISTER NOW!
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Follow me on: Facebook “Fin Page” – YouTube – Blog – Linkedin – Twitter

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Yours sincerely,

Dr Richmond Loh
BSc, BVMS, MPhil (Vet Path), MANZCVS (Aquatics), MANZCVS (Pathobiology), DipPM.
Veterinarian | Adjunct Senior Lecturer Murdoch University | WAVMA President-Elect |
Secretary Aquatic Animal Health Chapter – Australian and New Zealand College of Veterinary Scientists (ANZCVS)
The Fish Vet, Perth, Western Australia, AUSTRALIA.

Dear Fish Fanciers,

Check out pictures at Ocean Park at this link.

Check out the Fa Yuen Street Wet Markets at this link.

Check out the array of ornamental fish shops along Tung Choi Street at this link.

Bigger initial investment, but ultimately, the non-fouling of nets means better water flow and better growing environment for the fish, reducing stress for better health and productivity, avoiding diseases and losses.

Aquaculture Economics & Management: Official Journal of the International Association of Aquaculture Economics and Management
Volume 17, Number 1 (March 2013)
	ECONOMIC IMPACTS OF USING COPPER ALLOY MESH IN TROUT AQUACULTURE: CHILEAN EXAMPLE
	Authors:	ExequielP. González 1, CarlosFelipe Hurtado 1, Langley Gace 2, Alberto Augsburger 3
	Author Affiliations:	1: School of Marine Sciences, Pontificia Universidad Católica de Valparaíso  2: International Copper Association Ltd.  3: Fundación Chile
	Source:	Aquaculture Economics & Management: Official Journal of the International Association of Aquaculture Economics and Management, Volume 17, Number 1 (March 2013)
	Page Numbers:	71 – 86
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: Unknown Location: Publisher’s Site Authentication: Publisher’s Site
	Abstract:	Commercial aquaculture continues to expand as it strives to meet growing global demand for healthier protein. In this context, farmers are under great pressure to address problems of biofouling and predation, all while reducing operational costs and losses. Copper alloy mesh (CAM) has been shown to provide solutions to these problems, yet there has not been an in-depth study of economic benefits of adopting this new technology. This study was conducted in Chile using one 2010 grow-out cycle of trout (Oncorhynchus mykiss) and combined productivity indicators with economic analysis based on investment theory. Results showed that CAM net yielded better productivity indexes and higher net economic benefits than those of nylon net with anti-fouling coating. Sensitivity analyses showed a greater effect on the profitability of nylon versus CAM and a reduced elasticity of pen profitability with respect to the rental cost of CAM.
	Citation:	ExequielP. González, CarlosFelipe Hurtado, Langley Gace, Alberto Augsburger . ECONOMIC IMPACTS OF USING COPPER ALLOY MESH IN TROUT AQUACULTURE: CHILEAN EXAMPLE. Aquaculture Economics & Management: Official Journal of the International Association of Aquaculture Economics and Management, Volume 17, Number 1 (March 2013), pp. 71-86, <http://ejournals.ebsco.com/direct.asp?ArticleID=4D49878F23A00F91C82D&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=4D49878F23A00F91C82D

Mycobacteriosis plagues the ornamental fish industry. From my experience, I can tend to diagnose fish disease in ornamentals based on the species. If it’s a Siamese fighting fish or a gourami that’s sick, it’s usually always fish TB. This condition is also very common in the live bearers and in danios. There is no cure for is. In animal research facilities, some manage it by turning over their entire collection every 6 months since such fishes are usually sourced from the local pet or fish store and they cannot guarantee their stock to be specific pathogen free.

Now in the aquaculture industry, work has been done to create an early diagnostic tool. I hope this technology will have a trickle down effect and that we may be able to utilise it in the ornamental industry. Perhaps we can use it to create and demonstrate specific pathogen free fish.

Read more about the test below:

From: “Dr. David Scarfe”
Date: 18 January 2013 0:58:35 AWST
Subject: AquaVetMed: New Information & Diagnostics on Mycobacteriosis in Fish

January 17, 2013
New Information on Mycobacteriosis in Fish

Norwegian School of Veterinary Science – Mycobacteriosis in fish is a disease that is difficult to detect and therefore often underdiagnosed. For the same reason, information about the effects of this disease on the fish farming industry has been limited. The development of two diagnostic tests has led to the discovery of a mycobacterium which causes disease in both cod and salmon and has never been detected in Norway before.
Reports submitted to the authorities of mycobacteriosis (tuberculosis) in fish have been sporadic and have only stemmed from aquarium fish or wild fish, not farmed fish. This is probably due to under diagnosis.

Adam Zerihun’s doctoral research has led to the development of two methods of diagnosis based on real-time PCR and immunohistochemistry respectively. The tests are extremely sensitive and have been instrumental in detecting a mycobacterium that has never been found in Norway before. The bacterium was found both in farmed salmon and in burbot and experimental infection showed that Atlantic cod was very susceptible to the bacterium and became diseased. The isolated bacterium was identified as Mycobacterium salmoniphilum.

In cod and burbot infected with M. salmoniphilum, Zerihun discovered serious nodules, while only small or no such changes were found in infected Atlantic salmon. The formation of nodules in cod was shown to undergo several phases of development. The identification and characterization of these different stages are important for the appraisal of disease development and in order to estimate the time of infection. Zerihun’s study indicates that the occurrence of the disease in farmed Atlantic salmon and in cod is more widespread than previously thought, both with regard to the range of host and climate variations.

Since the formation of nodules is not a typical symptom in salmon infected with M. salmoniphilum, it is highly probable that many cases of tuberculosis in salmon remain undiscovered. Fish that lose weight without there being any apparent disease or specific cause are classified in fish farming as “lost fish”. A mycobacterial infection can be lurking behind various different symptoms, where weight loss is one characteristic.

For this reason, many salmon infected with tuberculosis can be the undetected reason for losses in the industry. The stress that arises when many fish are kept in closely packed surroundings weakens their immune system and allows mycobacteria to reproduce in many individuals. These factors are known to promote the occurrence of mycobacteriosis.

[More information on Mulualem Adam Zerihun’s doctoral research and thesis (“Mycobacteriosis in marine and freshwater fishes: characterization of the disease and identification of the infectious agents”) is available at http://www.nvh.no/en/Home/News/News-stories/Mycobacteriosis-in-fish/. ADS-Mod.]

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This link was shared with me by Dr Nick Sainte-Erne.

Buy a fish, save a tree.