Author: TheFishVet - Richmond's School of Fish

Aquatic veterinary medicine, pathology and educational services for fish. A repository for useful information and events.

Can fish get a skin tan?

Posted on by TheFishVet - Richmond's School of Fish

If you ever see pond reared goldfish, you will notice that their colours are more vibrant and intense than their indoor counterparts. Could it be the effect of the sun? Could it be to do with supplementary feeds they get such as insects and algae? Probably a combination.

What I just learnt today though, is that hammerhead sharks can and do get skin tans!

Lumpy catfish, cause unknown. Pollution?

Posted on by TheFishVet - Richmond's School of Fish

Begin forwarded message:

From: noreply>
Date: 8 November 2011 6:20:06 AWST
To: Undisclosed Recipients
Subject: Disease News Update

AquaticHealth.net Disease News Update >> Catfish tumor – USA [ProMed request for information]

Link to source content: http://www.hometownannapolis.com/news/TOP/2011/10/31-31/Cause-of-catfish-tumors-still-unknown.html.

Your input is important: Please verify and add any relevant commentary to this report. Also, is the information in the report summarised somewhere in the Wiki?

Report Content:

CATFISH TUMOR – USA: (MARYLAND) REQUEST FOR INFORMATION

*******************************************************

A ProMED-mail post

ProMED-mail is a program of the

International Society for Infectious Diseases

Date: Mon 31 Oct 2011

Source: Howntownannapolis.com, The Capital Gazette [edited]

Cause of catfish tumors still unknown

How to increase fertility in fish

Posted on by TheFishVet - Richmond's School of Fish

Aquaculture International: Journal of the European Aquaculture Society Volume 19, Number 6 (December 2011)

Ovaprim treatment promotes oocyte development and milt fertilization rate in diploid and triploid African catfish (Clarias gariepinus)

Authors: Ali Karami 1, Annie Christianus 1, Hadi Zokaeifar 1, Khairul Saad 1, Fahmi Imraan 1, Shahram Shakibazadeh 1, Hossien Negarestan 2, Simon Courtenay 3 Author Affiliations:

1: Department of Aquaculture, Faculty of Agriculture, University Putra Malaysia, 43400 Selangor, Malaysia
2: Department of Aquatic Ecology of Caspian Sea, Iranian Fisheries Research Organization (IFRO), Tehran, Iran
3: Fisheries and Oceans Canada at the Canadian Rivers Institute, Department of Biology, University of New Brunswick, Fredericton, NB, Canada

Source: Aquaculture International: Journal of the European Aquaculture Society, Volume 19, Number 6 (December 2011) Page Numbers: 1025 – 1034 Available Full Text:

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Abstract:

Abstract

Triploid fish are increasingly used in aquaculture because they are generally unable to reproduce successfully. Energy is channeled into somatic growth rather than gonadal development, and in the event of escape, the animals are unlikely to breed successfully among themselves or with wild conspecifics. This study tested the ability of recently matured triploid African catfish (Clarias gariepinus) to produce and fertilize eggs with and without ovaprim treatment. Triploid females did not show the increase in ovary size observed in diploid members of the same cohort between 8 and 9 months of age, or the coincident decrease in visceral fat deposits, and this was unaffected by up to 5 weekly i.m. injections of 0.5 ml kg-1 Ovaprim. However, we observed advanced vitellogenin (Vtg) sequestration in oocytes of triploid females, albeit to a lesser degree and with lesser cortical alveoli, compared to oocytes from diploid cohort members. Histological sections revealed a positive trend of oocyte development up to the third weekly ovaprim injection followed by a negative gonadal development in weeks four and five. Milt from triploid males injected 9–12 h earlier with 0.25 ml kg-1 ovaprim i.m. fertilized more diploid eggs than milt from untreated triploid males (30 vs. 20%), but none of the developing embryos of triploid paternity survived to hatch. In contrast, milt of diploid males fertilized 49% of eggs, and 20% of the developing embryos hatched successfully. These rates were improved in ovaprim-injected diploid males to 70% fertilization and 33% hatch. This study demonstrates potential of overcoming non-viability of eggs from triploid female African catfish, and enhancing the ability of triploid milt to fertilize eggs.

Citation: Ali Karami, Annie Christianus, Hadi Zokaeifar, Khairul Saad, Fahmi Imraan, Shahram Shakibazadeh, Hossien Negarestan, Simon Courtenay . Ovaprim treatment promotes oocyte development and milt fertilization rate in diploid and triploid African catfish (Clarias gariepinus). Aquaculture International: Journal of the European Aquaculture Society, Volume 19, Number 6 (December 2011), pp. 1025-1034,