The Fish Vet's Blog

Tank wall collision is one of the major causes of mortality during the early-stage rearing of Pacific bluefin tuna. This paper details changing the water flow rate as a preventive measure.

I wonder if an air-bag would work… But seriously, have a ring of air around the tank sides.

Aquaculture International: Journal of the European Aquaculture Society
Volume 21, Number 1 (February 2013)
	Critical swimming speed and maximum sustainable swimming speed of juvenile Pacific bluefin tuna, Thunnus orientalis
	Authors:	F. S. Sabate 1, Y. Nakagawa 1, T. Nasu 1, W. Sakamoto 1, S. Miyashita 1
	Author Affiliations:	1: Fisheries LaboratoryKinki UniversitySakata 1-5Shirahama, Wakayama649-2211Japan
	Source:	Aquaculture International: Journal of the European Aquaculture Society, Volume 21, Number 1 (February 2013)
	Page Numbers:	177 – 181
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Tank wall collision is one of the major causes of mortality during the early-stage rearing of Pacific bluefin tuna, Thunnus orientalis(PBT). Therefore, to design a rearing environment that meets the needs of juvenile PBT, it is important to gather information about their swimming capabilities. We conducted experiments to examine the relative critical swimming speed (RCSS) and maximum sustainable swimming speed (MSSS) of early-stage PBT. The fish were kept in 3-tonne tanks and fed on artificial pellets every 2 h from dusk to dawn. We conducted two sets of experiments to measure swimming speed; the fish were introduced one at a time into a water funnel, and the water current velocity was gradually increased over time to estimate RCSS, or the water current was kept at a constant velocity to estimate MSSS. We measured the RCSS of 72 PBT juveniles (24–29 days after hatching (DAH); standard length (SL), 15.0 ± 2.3 mm) and the MSSS of 32 PBT juveniles (28–37 DAH; SL, 20.0 ± 5.1 mm) in the laboratory. The RCSS ranged from 4.7 to 20.3 SL/s (average, 12.4 ± 3.3 SL/s), and the MSSS was estimated to be approximately 4 SL/s. We speculate that introducing a water current in the rearing tank of no more than 4 SL/s could positively affect the survival of juvenile PBT.Tank wall collision is one of the major causes of mortality during the early-stage rearing of Pacific bluefin tuna, Thunnus orientalis(PBT). Therefore, to design a rearing environment that meets the needs of juvenile PBT, it is important to gather information about their swimming capabilities. We conducted experiments to examine the relative critical swimming speed (RCSS) and maximum sustainable swimming speed (MSSS) of early-stage PBT. The fish were kept in 3-tonne tanks and fed on artificial pellets every 2 h from dusk to dawn. We conducted two sets of experiments to measure swimming speed; the fish were introduced one at a time into a water funnel, and the water current velocity was gradually increased over time to estimate RCSS, or the water current was kept at a constant velocity to estimate MSSS. We measured the RCSS of 72 PBT juveniles (24–29 days after hatching (DAH); standard length (SL), 15.0 ± 2.3 mm) and the MSSS of 32 PBT juveniles (28–37 DAH; SL, 20.0 ± 5.1 mm) in the laboratory. The RCSS ranged from 4.7 to 20.3 SL/s (average, 12.4 ± 3.3 SL/s), and the MSSS was estimated to be approximately 4 SL/s. We speculate that introducing a water current in the rearing tank of no more than 4 SL/s could positively affect the survival of juvenile PBT.
	Citation:	F. S. Sabate, Y. Nakagawa, T. Nasu, W. Sakamoto, S. Miyashita . Critical swimming speed and maximum sustainable swimming speed of juvenile Pacific bluefin tuna, Thunnus orientalis. Aquaculture International: Journal of the European Aquaculture Society, Volume 21, Number 1 (February 2013), pp. 177-181, <http://ejournals.ebsco.com/direct.asp?ArticleID=45D686120F3F3CD3180A&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=45D686120F3F3CD3180A

It’s not been an easy road to acquire specialised knowledge, skills and training as described by a colleague, even in the US. So, they have compiled a list of training providers and their courses on their blog.

Check it out here:

http://avsnca.com/aquatic-veterinary-medicine-resources/comment-page-1/

There will also be a couple of courses being run in Australia this year; in July (https://thefishvet.com/2013/01/11/2013-frdc-australasian-scientific-conference-on-aquatic-animal-health/)
and another in August (https://thefishvet.com/2012/12/28/the-24th-international-conference-of-the-world-association-for-the-advancement-of-veterinary-parasitology-will-be-in-perth-australia/).

Also, join WAVMA to network with other fish vets.

Why culture for bacteria? The answer can be found in a previous post (
https://thefishvet.com/2012/10/13/whats-the-best-antibiotic-to-treat-sick-fish-with/).

But do you ever have trouble trying to take an aseptic sample from the kidney of a tiny fish and find that the giant cotton wool swab ends up swabbing everything, but the kidney?

Ensuring that you take a targeted sample will ensure that whatever the bacteriology laboratory isolates, itis likely to be significant, rather than mere environmental contaminant.

Also, my fish bacteriologist colleague says that aquatic bacteria survive better in Amies transport media that contains charcoal.

This swab pictured is the ideal design for fish vetting and it’s what I carry in my kit at all times.

These bacterial transport swabs with small tips are perfect for aseptically sampling from small fish organs. The charcoal media guarantees longevity of the bugs so they can reach the lab alive.

Enquire with TheFishVet regarding supply of these Transwabs for your veterinary clinic or laboratory.

—
Yours sincerely,

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

I had a flurry of questions about the blood testing. The most common one was, what is the minimum amount of blood we need in order to run a full biochemistry panel?

The minimum amount of blood we need is 0.5mL. Blood collection tubes come in all sizes and I’ve included a picture of the common sizes used (from left to right, 10mL, 5mL, 2mL and 1mL). The amount of anticoagulant to blood ratio shouldn’t be too much of a problem if running a biochemistry panel. It is only an issue if you’re wanting haematology since excess anticoagulant can rupture your cells, and too little will lead to a clotted blood sample. Of course there are a heap of other complications, but I’d best leave that to a specialist clinical pathologist to answer.

In a race, what would you say to cheer a fish on?

GO! Rami!
(gourami)

Read more
http://news.nationalgeographic.com/news/2013/130109-shark-embryo-freeze-predator-animals-science

http://smithsonianscience.org/2013/01/first-detailed-sex-video-of-deep-sea-squid-penetrates-long-standing-mysteries-as-to-how-these-animals-mate/

This course is taught byDr. Donald Lightner and his colleagues from the Aquaculture Pathology Laboratory at the University of Arizona.  This intensive course consists of comprehensive lectures and practical laboratory training that is focused on current methods used to diagnose, prevent, and treat the principal diseases of cultured penaeid shrimp. This program also provides an excellent opportunity for participants to meet and interact with others involved in shrimp disease research and management.

More information available at
http://microvet.arizona.edu/research/aquapath/index.htm

This information brought to my attention from WAVMA’s email list-serve.