The Fish Vet's Blog

Check the female for a knob 🙂

Journal of Applied Aquaculture
Volume 25, Number 2 (April 2013)
	A Practical Approach for Sexing Zebrafish, Danio rerio
	Authors:	Rodrigue Yossa 1, PallabK. Sarker 1, Emilie Proulx 1, Vishal Saxena 2, Marc Ekker 2, GrantW. Vandenberg 1
	Author Affiliations:	1: Groupe de Recherche en Recyclage Biologique et Aquiculture, Département des Sciences Animales, Université Laval 2: Center for Advanced Research in Environmental Genomics (CAREG), Department de Biology, University of Ottawa
	Source:	Journal of Applied Aquaculture, Volume 25, Number 2 (April 2013)
	Page Numbers:	148 – 153
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: Unknown Location: Publisher’s Site Authentication: Publisher’s Site
	Abstract:	This study aimed at a simple, rapid, reliable, practical, and non-destructive sexing technique for mature zebrafish (0.61 ± 0.011 g each). In the first experiment, 36 fish of each sex were selected on the basis of the presence of a prominent genital papilla on mature females and bred randomly. All the couples laid fertilized eggs with a mean fecundity of 304 eggs per female, for a 100% sexing accuracy. In the second experiment, 140 mature zebrafish were randomly selected and individually sexed like in the first experiment. Each fish was then dissected in order to confirm the reliability of this sexing technique through the observation of either the ovaries or the testes. Upon dissection, an accuracy of 100% was recorded. This study demonstrates that sexing mature zebrafish only on the basis of the presence of a prominent genital papilla on the mature female is a reliable technique.
	Citation:	Rodrigue Yossa, PallabK. Sarker, Emilie Proulx, Vishal Saxena, Marc Ekker, GrantW. Vandenberg . A Practical Approach for Sexing Zebrafish, Danio rerio. Journal of Applied Aquaculture, Volume 25, Number 2 (April 2013), pp. 148-153, <http://ejournals.ebsco.com/direct.asp?ArticleID=441D8D6F9022E861DB47&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=441D8D6F9022E861DB47

This is a simple and well-laid out experiment to produce the data needed by licensing authorities to test for the safety of using antibiotics in fish. Here they were able to establish a 500 degree day witholding period for florfenicol in rainbow trout.

 

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Journal of Fish Diseases
Volume 36, Number 8 (August 2013)
	Florfenicol depletion in edible tissue of rainbow trout, Oncorhynchus mykiss(Walbaum), and sea bream, Sparus aurataL.
	Authors:	A Di Salvo, G della Rocca, E Terzetti, J Malvisi
	Author Affiliations:	no affiliations available
	Source:	Journal of Fish Diseases, Volume 36, Number 8 (August 2013)
	Page Numbers:	685 – 693
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	An increase in fish production has consequently brought an increase in infectious diseases in fish farms. The use of chemotherapic drugs is the most effective instrument against common bacterial agents. The number of registered drugs for use in aquaculture is limited and often veterinary practitioners resort to the off-label use of chemotherapic agents authorized for different food-producing animal species. Florfenicol is well known for its outstanding effect against various pathogenic bacteria affecting fish, and therefore, it may be a useful drug for off-label use in aquaculture. The aim of this study was to evaluate the depletion of florfenicol and its major metabolite, florfenicol amine, from the edible tissue of two fish species, rainbow trout and sea bream, following treatment with medicated feed at a dosage of 10 mg kg-1of bw day-1, for 10 consecutive days. At prefixed time points after the end of administration (0.25, 1, 2, 3, 4, 6, 7, 10, 14 and 21 days after treatment), edible tissues (muscle plus adherent skin) from 15 individuals in each group were collected and analysed by HPLC, to determine concentration of the drug in the tissue. On the basis of the obtained concentrations, withdrawal times of florfenicol in the two species were calculated. The results indicate that a drug withdrawal time of 500 °C-day, as established by Directive 2004/28/EC, for off-label drug use is more than satisfactory to guarantee the healthiness of fish products against the risk of drug residues.
	Citation:	A Di Salvo, G della Rocca, E Terzetti, J Malvisi . Florfenicol depletion in edible tissue of rainbow trout, Oncorhynchus mykiss(Walbaum), and sea bream, Sparus aurataL.. Journal of Fish Diseases, Volume 36, Number 8 (August 2013), pp. 685-693, <http://ejournals.ebsco.com/direct.asp?ArticleID=486D87E380E1F12864A6&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=486D87E380E1F12864A6

It’s got tornadoes and sharks combined for full evil effect –

—
Yours sincerely,

Dr Richmond Loh
DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics& Pathobiology).
The Fish Vet, Perth, Western Australia.
Veterinary Medicine for fish.
W: http://www.thefishvet.com.au
E: thefishvet
P: +61 (0)421 822 383

 

Not only the Secretary position, but also the Treasurer position!

Roles of Chapter office bearers:

President
The President is an officer of the Chapter who is appointed or elected to preside over the Chapter. The President chairs Chapter meetings and manages all Chapter activities.
Secretary
The Chapter secretary conducts correspondence, takes minutes of meetings, keeps records and performs secretarial duties for the Chapter.
Treasurer
The Chapter Treasurer is in charge of receipting and caring for the funds of the Chapter. Chapter Treasurers must ensure Chapter accounts are managed according to the College directions in relation to budgeting, banking, GST activity reporting and auditing
requirements.

AQUATIC ANIMAL HEALTH CHAPTER
The Chapter of Aquatic Animal Health is a very diverse interactive group of veterinarians as this Chapter covers all aquatic animals (apart from reptiles, amphibians, birds and mammals), with particular emphasis on those species which are kept for aquaculture or otherwise commercially exploited, including but not limited to teleost fish, bivalve molluscs, marine shrimps (prawns), freshwater crayfish and abalone. Disciplines include medicine and management, pathobiology and epidemiology of aquatic animal diseases. Members of this Chapter aim to exchange knowledge and promote excellence in the diagnosis, treatment and prevention of diseases of aquatic animals, to advance the science and art of veterinary science as it relates to aquatic animals, and to further the professional education and training of veterinarians with a special interest in aquatic animal health. The Chapter also aims to encourage research in aquatic animal health, and to encourage exchange of knowledge with and collaborative work with other scientists working in the field of aquatic animal health.

How do you become a Member of the ANZCVS?

The award of Membership of the College is conferred upon a veterinarian who is eligible to sit and successfully passes an examination in a given Membership subject.

Candidates for Membership of the College should be eligible for registration as a veterinarian in an Australian State or in New Zealand. Candidates must have spent at least four years in a full-time veterinary activity between graduation and taking the examination.

Applicants will be assessed on their knowledge and skills at the Membership examination. Performance in the Membership examination is assessed on the basis that the candidate shall achieve a pass mark of 70% or above.

“The candidate is expected to demonstrate a high level of interest and competence in a given area of veterinary activity. This is judged by that standard of knowledge and understanding, practical skills, attitude, methodology and communication which would make the person suitable to give professional advice to veterinary colleagues not similarly qualified on problems or procedures often encountered or used in general practice, in the relevant area of veterinary endeavour.”

For more information, go to http://www.anzcvs.org.au

I had a question about whether they should purchase a new tank or an old tank. Everyone loves new, but can you go old too?

From a looks perspective, you may notice unsightly water marks as minerals may be deposited on the glass. This can be easily cleaned off using warm water or dilute vinegar. Don’t worry about light scratches on the tank as they will look invisible once the tank is filled.

From a disease point of view, if the old tank is dry and has been out of circulation for several months, then there ought to be no issues. If in doubt, you can always disinfect with chlorine/bleach and then make it fish-safe again by thorough rinsing and by the use of dechlorinators.

From a practical perspective, you cannot be sure whether the tank will hold up or leak, especially if the tank has been dry for some time. Thus, it is always best to fill the tank in stages. Day 1, fill it to 30% capacity. If no leaks, then fill it to 50% capacity on Day 2. On Day 3, it might be safe to fill it to the maximum water level. Leave it for a week at least prior to stocking the tank.

Biologically, when moving fish from their old tank to their new home, make sure you use as much of the old tank gravel, water, furnishings and filtration equipment to avoid bringing about ‘new tank syndrome’. See fact sheet entitled “Ammonia, nitrite and nitrate” at http://thefishvet.com.au/fact_sheets.html

Does the tank size or water volume affect their growth rate? Last year, I attended the Aquavet II course in the USA. I learnt that the most recent research finding for recirculating aquaculture system (RAS) is that the “partitioned aquaculture system” (PAS) may improve yield per unit total volume or area. The PAS works by dividing the pond to allow 2/3 for the biofilter and only 1/3 for the cultured fish to occupy. The reason for the increased efficiency is not yet understood and this could be investigated further in Australian conditions.

So, I did a short semi-scientific experiment of a different kind with four goldfish. Two fish were in Group A, and they spent their time in a 95L aquarium. Two fish were in Group B, and they spent 3 months in a 4500L set up which was compartmentalised to have a similar amount of swimming space as Group A. Pictured below are two goldfish of the same age.

 

The smaller one belongs to Group A. The larger fish belongs to Group B. Look at the difference in size. At the completion of the experiment, body weights of the small fish were 14g and 16g and the body weights of the large fish were 50g and 59g! That’s a whopping 4x heavier!

What implications does this have for fish breeders and farmers? This experiment shows that water volume, rather than swimming space, plays an important role in goldfish growth rates. This may be to do with better water quality? Maybe production of the growth inhibiting hormone was suppressed (link to previous post). Maybe we could get even better results with a flow through system.

 

Check this out!
http://www.news.com.au/travel/australia/whale-injures-surfers-at-bondi-beach/story-e6frfq89-1226675505920

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—
Yours sincerely,

Dr Richmond Loh DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics & Pathobiology).
Veterinarian | Adjunct Lecturer Murdoch University | President-elect WAVMA |
Secretary Aquatic Animal Health Chapter – 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

Looking for more books? Check out this site.

The NSW Aquaculture Association is holding a 2 day Recirculating Aquaculture and Aquaponic short course you will be interested in.

Tickets are now on sale through the following link:
http://aquacultureaquaponicscourse.eventzilla.net/

Prices are as follows:
General registration will be $280 total for the two days
This is for anyone to register and attend the full two day short course.

NSW Aquaculture Association Members will be $210
This is for full financial members of NSW Aquaculture Association

Students registration will be $230 (a copy of your student ID card will need to be sent prior).

This is for students currently studying at any accredited institution
I can be contacted directly at president@nswaqua.com.au or by phone on +61 (0)439 468 201 (email should be your first point of call).

Regards
Paul Van der Werf
President

Event Description
We will be covering a range of topics suitable to anyone wanting to learn more about designing and operating recirculating aquaculture or aquaponic systems of any size over the intense two day short course presented by Dr Tom Losordo and Dr Wilson Lennard.

Some of the topics that will be covered during this workshop (Full list of topics to be confirmed):

System design and management

Aeration
Plumbing
Components
Construction Techniques
Operation

Fish production

Stocking
Feeding, growth and survival
Harvesting and processing
Water quality

Plant Production

Seedling production
Importance of pest identification
Disease and insect control
Nutrient dynamics

Economics and Marketing

Aquaponics economics
Effect of scale vs Available market
Marketing Fish
Marketing Plants

About the Presenters:

Dr. Tom Losordo is the Director of Aquaculture Systems Engineering for Pentair Aquatic Eco-Systems. Dr. Losordo has a Bachelor degree in Biology and an M.S. and Ph.D. in Biological and Agricultural Engineering. Having been involved in aquaculture for more than 38 years, Dr. Losordo recently retired as head of a program of applied research and extension at North Carolina State University in the area of recirculating aquaculture production systems.

Dr. Wilson Lennard is the Director of Aquaponic Solutions and has been studying aquaponics for the past 10 years. He is a PhD graduate from Australia (RMIT University, 2006) with practical commercial aquaponics experience and knowledge. Wilson also has scientific and engineering skills and experience in associated aquatic disciplines, including freshwater aquaculture, marine aquaculture, hydroponics, integrated aquatic farming systems, freshwater aquatic ecology and environmental biology. These skills and experience have been accumulated over a professional scientific career of almost 20 years.

Venue and cost

The venue will be the Soldiers Point Bowls Club, 118 Soldiers Point Rd, Soldiers Point NSW 2317 We are arranging for discounted accommodation rates which are located next to and across the road from the club (walking distance). So hold off on booking your accommodation.

Date: 21 September 2013.