Shark and ray diseases

[exoticvet]

I´m a vet who is trying to help a newstarted public sharkaquarium keeper.
He got 3 Blacktipped reef sharks one month ago 1 male 2 females.
The male one did eat wery well for 2 weeks stopped eating and found dead next morning. 3 different bakteria is growing pseudomonas and something more.(not finished) On autopsy did I find bleedings in the spermreservoir, no parasites. Histopathology is on the way.

One of the 2 females has not been eating for 4 weeks and she sems to be in a hurry, swimming towards water autlet and swimming with the tail below horisontal line. Anny hint what to do waiting for the Histology and bakteriology and resistens report.
Water quality is pH 8,3 Salinity 1,022, Nitate 5-10, Nitrit and ammoniac -0

Best regards from a rainy sweden
[email protected]

 

[jsmkmavity]

silinity sounds a little low for sharks rays and eels. maybe steve will chime in if he knows these fish as well as others.

 

[steve-s]

How large are these sharks?
When the sharks were eating, what and how often?
What if any treatments have you employed on the sharks?
You say no parasites, all internal and external have been eliminated? If so how or was it necessary?
What is the overall appearance of the sharks, color, eye, skin ect?
Please provide much more information about the tank and maintenance performed regularly.

 

[exoticvet]

Hello Steve The BT reef sharks are around 1 m and are swimming in a 75 m3 tank. The tank keeper belive that they are feed up in tank perhaps in holland before delivery. About eating schedule, will I return when I have the English namnes on the food. I said no parasites as I did not see any but as I do not know much about sharks I could have missed a lot of not obvius for the eye parasites. I tock some imprints on glas to the fish pathologist that I have not got any answer from yet. As far as I could see were there no discolorations on the body a 5 mm rounded grey hard falling apart area on one eye. blood in the opening between the " back underbelly fins??" The equipment is up to date and water is regular chanced. UV ligt and surfase cleaner and sand filters.
No treatment more then lowering of salinity to 1,022 from 1,024

 

[steve-s]

Most shark parasites will be in the gill area or gut. The area around the eye is definitely a concern.

It will help to know the foods and feeding schedule. I am also a little lost on what 75 m3 refers to in terms of tank size. What is the volume in liters?

Why is the salinity not being kept stable? 1.022 is lower than it should be, 1.024 would be the preferred level. Do you know how often this is changing?

So far what your describing seems to be a systemic bacterial infection. The most likely cause will be a high level of dissolved organic compounds in the tank water. When will your lab results be back?

 

[exoticvet]

Hello steve
The tank is around 75000 liter .the owner had heard from the salesman of the sharks that a way to treat parasite problem was to lower the salinity, I have told him to raise it to 1,024 again. I will return to you with feading scedule and I hope I will have more bakteriologi answers tomorrow.
My best regards
Tomas

 

[steve-s]

I am guessing this is from a public aquarium of some sort? That's a pretty hefty system. Do you know how it was constructed? Concretes, glass, metals etc?

On the parasite issue... what was being treated, how low did the salinity get and for how long?

Elasmobranchs cannot tolerated lowered salinities for too long, if at all. Hyposalinity levels should only be performed on Teleost species of fishes, never cartilaginous species. They actually cannot rid themselves of body waste in reduced salinities.

Anything on the food yet?

 

[exoticvet]

More about those Blacktipped reef sharks food and environment

Lifesupport system:
Display tank 75 000 liter of water
* Proteinskimmer (70 000 l/h)
* 4 biological sandfilters (25 000 l/h each)
* 3 UV sterilisation units (10 000 l/h each)
* Denitrifikation filter
Above this
* Extra pumps for circulation (100 000 l/h)

Food we have tried:
Herring, makrel, salmon, ansjovis, pike, smelt, squid salwaterfish and fresh fish and more...
Vi have tried daytime and evnings on dayli basis and 3 times a week

Water parameters:2006-11-26
Temp.: 25 C
Salinity: 1.022
pH: 8,2
KH: 7,4
Nitrate: 10 mg/l
Nitrite: 0
Ammonia: 0

The salinity was lowerd becouse the tankkeeper was told from someone in holland that it shuld be a tratment against parasites. I have told him after your advice to raise it to 1,024

The tank is in ground made in concreate and glas with the concreate coverd with a recomended 2 komponent plastic on all surface towards the water.

Best regards
From sweden

 

[shallowreef]

Shouldn't your nitrates be Zero? I was always told with keeping sharks and rays that your nitri and nitra need to be zero.

 

[steve-s]

Food we have tried:
Herring, makrel, salmon, ansjovis, pike, smelt, squid salwaterfish and fresh fish and more...

Live or dead, fresh or frozen?

There is a serious risk of introducing pathogens depending on the foods condition. Not much you can do about bacterial but parasites are easily introduced using foods that have not been previously frozen.

Are the foods being removed once left by the sharks?

The salinity was lowerd becouse the tankkeeper was told from someone in holland that it shuld be a tratment against parasites. I have told him after your advice to raise it to 1,024

As long as it did not go below 1.022 you not too bad off. 35-36.5 ppt is the ideal range for these creatures.

Do you know what parasite was being treated? Was the parasite eliminted?

The tank is in ground made in concreate and glas with the concreate coverd with a recomended 2 komponent plastic on all surface towards the water.

Your sure there is no metal in the tank at all?

So far, I still say it's looking like a systemic bacterial infection. Force feeding antibiotics via foods with a tube may be your best option.

Are your test results in yet?

 

[steve-s]

Shouldn't your nitrates be Zero? I was always told with keeping sharks and rays that your nitri and nitra need to be zero.

There's still some give here but your right, nitrate should be as low as possible. The main reason being how sharks expel wastes. If the surrounding waters are less than desirable, they'll just take it back in (see...Maintaining the Internal Sea ). 10 ppm will not be life threatening though. The biggest issue here would be opportunistic bacteria.

 

[exoticvet]

Hello
The diskussion about parasites was a telephone diskussion betwen the owner and someone in holland - No parasites has ben found as far as I know.
And the salinity was lowerd from this rekomendation from holland.
I have advised him after your hint to raise the salinity to 1,024


We have been talking about havey metals (toxic to sharks, for.ex, Cu) the keeper is well avere of that.

Something I think about is how much stress will the sound from waterpumps throu water make to sharks. And I supose that even sharkes have an individuel differense in how much stress thay can take.

I will be in touch when I got more from lab.

Regards from sweden

 

[steve-s]

We have been talking about havey metals (toxic to sharks, for.ex, Cu) the keeper is well avere of that.

Not just copper, any/all metals. The construction of the tank can contain no exposed metal. Your post suggests your already aware of that but I just wanted to be sure.

I will be in touch when I got more from lab.

 

[exoticvet]

BT reef sharks

Laboratory results has confirmed your thoughts about infection


Orhit was diagnosed with an abscesses and muscle fiber damage in hart and bodymuscles and damage in kidneys.
Pseudomonas, and Enterobakteriase sensitive to Tetracycline and Gentamycin has been found.
The death of the male BT shark was coursed of sepsis after an orchid infection .

Now I will try to treat the female shark that have not been eating.

Do you have Any recommendations of these antibiotics to choose – I´m thinking about as few treatments as possible .

In mammals can you give twice the dose ,each other day of Tetracycline –can this be done in sharks. Is Doxycykline usefull.

What about Gentamicin in sharks - In mammals there are hearing, kidney and liver damage easy.

regards from Sweden

 

[steve-s]

Generally I would much prefer the use of Gentamycin but given the analysis of the kidneys, it would be too much strain on the animal. The Doxycycline would be an excellent alternative as it will not impair the kidneys. It is from the Oxytetracycline group.

Watch for discoloration of skin and teeth, they can yellow but not a concern. Also be on the watch for skin irritation. Dosage should be at a rate of 5mg/kilo of fish weight for Doxycycline.

 

[exoticvet]

Hello Steve do you know how to calculate the bodyweight on a swimming shark
in this case 1 m BT reef shark
I got information know from the owner that the shark weight is 7-8 Kg bodyweiht and she did start to eat after the salinity was slowly rising- and I´m no going to give her Doxycycline 100 mg each other day in the food do you thing that will be ok.

I do appreciate your help.
Best regards

 

[NaH2O]

Welcome exoticvet to Reef Frontiers!!!

I just wanted to welcome you and follow along with the information in the thread.

 

[steve-s]

Hello Steve do you know how to calculate the bodyweight on a swimming shark

No, it's all voodoo :lol: I couldn't guess the weight of something sitting still.

in this case 1 m BT reef shark
I got information know from the owner that the shark weight is 7-8 Kg bodyweiht

That sounds about right....
http://www.flmnh.ufl.edu/fish/Gallery/Descript/Blacktip/Blacktipshark.html

and she did start to eat after the salinity was slowly rising- and I´m no going to give her Doxycycline 100 mg each other day in the food do you thing that will be ok.

Great news on the feeding, that will make this so much easier. Every other day feedings would not be my first choice. It leaves room for the bacteria to bounce back. I would feed less food daily and also less on the med. If your friends weight calculation is correct, I would dose at a rate of 35 mg Doxyciline daily in foods for a minimum of 7 days (max 10 days).

 

[exoticvet]

BT reefsharks

Hello Steve
The reason to feeding every 2 days is that the owner does not think that the shark will eat every day. I thought that as with oxytetrcyklin where you can rise the dose and length the time between, you will have a accepted result but not ideal. I did the medication to one 100 mg tablet each other day to keep the blood level higher for a longer period of time. ½ time for doxycyklin is twice as long for doxycyklin as for tetracycline (Dox.18-22h for humans10-12 Tetra) I do not know the shark liver/kidney breakdown time for doxycyclin.
It would be interesting to know the antibiotic blood levels during treatment.
If I get a Chance to take a blood sample - where do I take it in a shark-I suppose they have same surface veins or do I take it with a hart injection ??
When treating mammals with antibiotics - I usually treat until the animal seems to be completely healthy and then another 2 days. With sharks and a lower
body turnover speed should´t I do the treatment for a longer time. With birds and reptiles there can I rise the temperature in the environment and in that way rise the efficiency of there antibody system and speed up the treatment - could this be done with sharks - rise the water temperature to get this benefit ??
More questions with regards from Sweden

 

[NaH2O]

Exoticvet - in the book Fish Medicine by Stoskopf, it indicates collecting blood from the Caudal Vein of the shark. The book also indicates that "prepping the shark skin with alcohol is very irritating and results in local erythema and induration. It is unnecessary and ineffective."

I pulled a few links that might help with locating the caudal vein, if Steve feels the samples are necessary.

Shark Cardiovascular System Photos - the Caudal Vein photo is the very bottom, left side

Caudal Vein

From: Journal of Aquariculture & Aquatic Sciences - Volume 5, Number 3

The blood sample is also frequently called into play. Blood is easily obtained from the caudal vein (Fig 1). This vein runs ventral to the cartilaginous tail vertebrae, encased in a cartilaginous canal. It is just ventral to a similarly encased caudal artery. The vein is easily sampled by inserting an appropriate length, large-bore needle on the ventral midline. The needle should be angled to pass dorsally and slightly anteriorly (Stoskopf et al., 1984). A distinct pop is felt as the needle enters the cartilaginous chamber containing the vein. The most common error in attempting to hit this vein is being off of midline. This vein can also be used to administer drug.