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,

How to grow super abs

Posted on by TheFishVet - Richmond's School of Fish

Aquaculture Volume 321, Number 3-4 (December 2011)

Organic acids as potential growth promoters in the South African abalone Haliotis midae

Authors: Neill Jurgens Goosen, Johann Ferdinand Görgens, Lourens Francois De Wet, Hafizah Chenia Author Affiliations:

no affiliations available

Source: Aquaculture, Volume 321, Number 3-4 (December 2011) Page Numbers: 245 – 251 Available Full Text:

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Abstract: The study investigated organic acids and organic acid salts as growth promoters in cultured South African abalone Haliotis midaewhen incorporated as feed additives in formulated feed. Two blends of organic acids (1% acetic acid+1% formic acid, and 1% benzoic acid+1% sorbic acid) and one of organic acid salts (1% sodium benzoate+1% potassium sorbate) were evaluated in South African abalone (23mm initial mean length), and tested against a negative control and positive control containing 30ppm avilamycin as antibiotic growth promoter (AGP). Experiments were performed at controlled water temperatures under optimal (Phase 1) and sub-optimal (Phase 2) temperatures. During Phase 1 the organic acid and organic acid salt blends significantly enhanced mass growth rate (both linear weight increase [AGRW] and specific growth rate [SGR]) compared to both controls. Linear length increase (AGRL) was significantly higher than the negative control. SGR was increased by 15.8%–17.9% relative to the negative control; AGRW and AGRL were between 12.9%–22.9% and 11.7%–13.5% higher, respectively. No significant growth enhancement was observed during Phase 2. Avilamycin had no effect on growth and none of the treatments had significant effects on feed conversion ratio (FCR), relative incidence cost (RIC, relative to negative control) or feed intake during either phase. The mode of growth enhancement could not be established; it could not be shown that the acid and salt treatments or the AGP had any effects on intestinal microflora, but possible energy effects of the acids were eliminated as potential mechanism; it is unclear what role gut acidification played in the enhanced growth performance.

Citation: Neill Jurgens Goosen, Johann Ferdinand Görgens, Lourens Francois De Wet, Hafizah Chenia . Organic acids as potential growth promoters in the South African abalone Haliotis midae. Aquaculture, Volume 321, Numbers 3-4 (December 2011), pp. 245-251,