The Fish Vet's Blog

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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AquaVetMed e-News provides information to veterinary and veterinary-allied subscribers concerning aquatic animal medicine, health, welfare, public health and seafood safety, obtained from a variety of sources (largely AquaVetMed subscribers). While provided by the American Veterinary Medical Association’s, Aquatic Veterinary Medicine Committee and are for public distribution, they do not necessarily reflect the opinion of the AVMA or the veterinary profession. See the AVMA Terms of Use (http://tinyurl.com/29h2rf) for further information.

If e-News information is used elsewhere please acknowledge AquaVetMed as the source. Encourage individuals to subscribe rather than distribute through list serves.

Messages may contain attachments that will have been scanned for known viruses.

Subscription and Contributions: Interested veterinarians and veterinary-allied professionals can subscribe, unsubscribe, or contribute pertinent news or information, by sending a message with “For AquaVetMed -” and the topic in the subject line, to dscarfe@avma.org.

Note: Undelivered e-mails will not be resent; Subscribers will be deleted from the list after repeated undelivered or bounced messages and will have to re-subscribe.

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

Buy a fish, save a tree.

It took five years and I’d expect, an enormous amount of funds and time to enforce the KHV ban to finally arrive at this outcome.

Countries that are currently KHV-free, stay on the alert.

From: “Dr. David Scarfe”
Date: 7 February 2013 2:27:07 AWST
Subject: AquaVetMed: DEFRA (UK) Lifts KHV Ban

February 6, 2013
Notification – Withdrawal of Confirmed Designations for Koi Herpesvirus (KHV)

UK Department of Environment, Food & Rural Affairs (Defra) – Confirmed Designations for the control of KHV disease have been lifted from all of the sites listed below following successful completion of a four year KHV monitoring and retest programme, conducted by the Fish Health Inspectorate at Cefas.

Each of the fisheries were placed under movement controls in the form of a confirmed designation notice for the control of KHV disease following an initial outbreak in 2008.

During the subsequent monitoring and retest period, there have been no further occurrences of clinical KHV disease and all samples of fish taken from these sites consistently tested negative for the presence of KHV.

Fisheries Involved
• Shirkoak Fishing Lake, Woodchurch, Ashford, Kent
• Pavyotts Mill Carp Fishery, East Coker, Yeovil, Somerset
• Lynsters Lakes and The Colne Valley Pits, Hertfordshire and Greater London
• Old Mill Fishery, The Old Mill, Stoford, Yeovil, Somerset
• Pine Lake Fisheries, Oak Field Farm, Kirton Lane, Thorne, Doncaster, S. Yorks
• Wassell Grove Fisheries, Wassell Grove Lane, Hagley, Stourbridge, Worcestershire
• Press Manor Fishery, Birkin Lane, Ashover, Chesterfield, Derbyshire
• Moor Hall Lakes, Moor Hall Farm, Ninfield, Battle, East Sussex

For more details see http://tinyurl.com/b3zlk6s.
___________________________
AquaVetMed e-News provides information to veterinary and veterinary-allied subscribers concerning aquatic animal medicine, health, welfare, public health and seafood safety, obtained from a variety of sources (largely AquaVetMed subscribers). While provided by the American Veterinary Medical Association’s, Aquatic Veterinary Medicine Committee and are for public distribution, they do not necessarily reflect the opinion of the AVMA or the veterinary profession. See the AVMA Terms of Use (http://tinyurl.com/29h2rf) for further information.

If e-News information is used elsewhere please acknowledge AquaVetMed as the source. Encourage individuals to subscribe rather than distribute through list serves.

Messages may contain attachments that will have been scanned for known viruses.

Subscription and Contributions: Interested veterinarians and veterinary-allied professionals can subscribe, unsubscribe, or contribute pertinent news or information, by sending a message with “For AquaVetMed -” and the topic in the subject line, to dscarfe@avma.org.

Note: Undelivered e-mails will not be resent; Subscribers will be deleted from the list after repeated undelivered or bounced messages and will have to re-subscribe.

Visit our website: http://www.avma.org
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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. 

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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. 

This article suggests it is too, with increased disease resistance being one of the benefits.

Read more here:
http://aquatichealth.net/node/70061

Lately, there has been a recent increase in popularity in nano fish keeping. Critters like the cherry shrimp are growing in popularity In Australia, there are reports of people smuggling in these critters in as they’re not legal imports and some enthusiasts have even been so bold as to advertise them for sale on fish forums and the like. Although I don’t condone such activities, perhaps those that are already in Australia and provided that they are disease-free (the biggest concern for importing crustacea is the White Spot Syndrome virus), can be kept in Australia for breeding and populating the hobby.

This research paper describes the breeding behaviour and reproduction of a freshwater prawn and the observations made by the authors might be useful in breeding crustacea like the cherry shrimp. I’m keen on the idea of small scale aquaculture and intend to get more expertise in this area when I travel to Hawaii and Florida in the middle of this year.

Aquaculture Research
Volume 44, Number 3 (February 2013)
On the breeding behaviour and reproduction of the freshwater prawn, Macrobrachium rosenbergii(de Man 1879) (Decapoda-Crustacea) under laboratory conditions

Authors: Madlen M Habashy
Author Affiliations:
no affiliations available
Source: Aquaculture Research, Volume 44, Number 3 (February 2013)
Page Numbers: 395 – 403
Available Full Text:
Full Text: Subscription Required to view full text
Format: PDF
Size: unknown
Location: Publisher’s Site
Authentication: EBSCOhost EJS

Abstract: The giant freshwater prawn, Macrobrachium rosenbergiiis one of the most common decapod species, and now getting more attention from the aquaculturists world wide due to its high market demand. It is commercially important because of its size as well as its eating flesh qualities. The breeding behaviour, reproduction and hatching of this species were observed for about 8 months during 2009. Juveniles (0.55 ± 0.177 g total weight and 2.7 ± 0.12 cm, total length) were reared in rounded fibre glass tanks (1.3 m, diameter). Pre-mating moult occurs in prawns once the ovaries ripen in their carapace cavity so as to transform the prawn into berried stage. Recorded incubation period ranged from 18 to 24 days. The number of eggs ranged from 2050 to 150 500 and the fecundity ranged from 435.2 to 3849.1 eggs. Number of hatched larvae ranged from 1825 to 123 410 larvae for females of 4.71 to 39.1 g respectively. The number of eggs carried by female prawn was directly proportional to its body weight (no. of eggs = 3441.3 wt. of female – 32 292, r2= 0.819). (fecundity = 82.066 wt. of female – 235.04, r2= 0.7779; fecundity = 317.86 length of female – 2651, r2= 0.833). Hatching rate ranged from 65% to 91%, and there was a correlation between number of hatched larvae and size of female parent (no. of larvae = 10 369 length of female – 102 965, r2= 0.8159; no. of larvae = 2792.9 wt. of female – 26 268, r2= 0.829). This study can greatly help in the management strategies of prawn hatcheries and improve its hatching technology.
Citation: Madlen M Habashy . On the breeding behaviour and reproduction of the freshwater prawn, Macrobrachium rosenbergii(de Man 1879) (Decapoda-Crustacea) under laboratory conditions. Aquaculture Research, Volume 44, Number 3 (February 2013), pp. 395-403,
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=4FCD8DA3D687DDB1CD5A

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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.
Mobile Veterinary Medical & Diagnostic Services for fish and other aquatic creatures.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383

In Vietnam, small scale fish farmers are finding it more profitable to make their own fish diets rather than rely on feed manufacturers. This is also a good idea from the farmer’s point of view because you cannot always rely on the feed manufacturer to make the food to your specifications. Already, there have been reports of manufacturers substituting fish proteins for cheaper proteins and the health of the farmed fishes suffer as a result. Apparently, feed mills change things all the time. The reasons may be that specific ingredients may be too expensive or unavailable, they may then substitute it with another, or reduce the inclusion rate.

One farmer, and likely several others, had experienced the effects of alleged feed substitution by a feed manufacturer such as muscle disease, poor immunity and more. This farmer had a great idea on how they could avoid this issue. They bypassed the local feed supplier and import their feed from overseas. The reason behind this is that the Australian Quarantine Inspection Service (AQIS) is very strict and one of the import requirements is that the ingredients must be reflected on the label and there must not be any changes. There was a lot of paper work to get through, but they’re now reaping the rewards from this ingenious idea.

It troubles me that feed manufacturers could do such things, thinking they can get away with it. Aquaculture in most of Australia tends to be a small industry and they tend to be lower on the priority list as clients. But this feed substitution also occurs in other animal feeds like poultry. Such malpractices will jeopardise the aquaculture industry and eventually, it would impact on the feed manufacturer in a trickle down effect. So, one way of avoiding the loss of control over what you’re feeding your farmed fish is to make your own fish food. This is the experience of the Vietnamese farmers as explained in the research paper below.

Aquaculture Research
Volume 44, Number 3 (February 2013)
Evaluation of potential feed sources, and technical and economic considerations of small-scale commercial striped catfish (Pangasius hypothalamus) pond farming systems in the Mekong Delta of Vietnam

Authors: Chau T Da, Le T Hung, Håkan Berg, Jan E Lindberg, Torbjörn Lundh
Author Affiliations:
no affiliations available
Source: Aquaculture Research, Volume 44, Number 3 (February 2013)
Page Numbers: 427 – 438
Available Full Text:
Full Text: Subscription Required to view full text
Format: PDF
Size: unknown
Location: Publisher’s Site
Authentication: EBSCOhost EJS

Abstract: A technical and socio-economic survey was conducted in Dong Thap, Can Tho and An Giang, provinces of Vietnam in 2009. The results showed that most of the small scale farmers of striped catfish (Pangasius hypothalamus) carry out fish pond culture, developed and operated by self-learned experience and from neighbours knowledge. The mean pond depth varied from 3.5 to 4.0 m, ranging from 2 to 6 m. Most of the fish farms have extremely high stocking density, with an average of about 40 fish m-2, in some cases up to 70 fish per m2. The average yields and net income of small-scales pond farming is about 21–27 kg per m2crop-1and US$ 0.184–0.329 kg-1crop-1respectively. These figures are not significantly different compared with large-scale pond farming. About 75%, 86% and 80% of fish farmers in Dong Thap, Can Tho and An Giang province, respectively, received positive net returns. Farm-made feed is still playing an important role because of higher net profit compared with commercial pellet feeds. Rice bran and trash fish are the main feed ingredients for farm-made feed formulations. Striped catfish farmers are now actively searching for locally produced plant protein sources as alternatives to marine trash fish or fish meal.
Citation: Chau T Da, Le T Hung, Håkan Berg, Jan E Lindberg, Torbjörn Lundh . Evaluation of potential feed sources, and technical and economic considerations of small-scale commercial striped catfish (Pangasius hypothalamus) pond farming systems in the Mekong Delta of Vietnam. Aquaculture Research, Volume 44, Number 3 (February 2013), pp. 427-438,
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=4C58B37C12DF2D660F6B
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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.
Mobile Veterinary Medical & Diagnostic Services for fish and other aquatic creatures.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383