Method to overcome surface tension for larval swim-up stage.

At the “swim up” stage in the development of larval fish, they need to get to the water surface to inflate their swim bladder. Sometimes the surface tension of the water may be too great and they aren’t able to penetrate it. This paper details a method to improve survival of small larvae by the addition of egg white and camphor grain to the water.

 

 

Aquaculture Research
Volume 43, Number 8 (July 2012)
Prevention of surface death of horse mackerel (Trachurus mediterraneus) larvae by the addition of egg white and camphor grain to rearing water
Authors: Ilhan Yandi 1, Ilhan Altinok 1
Author Affiliations:
1: Department of Fisheries Technology Engineering, Surmene Faculty of Marine Science, Karadeniz Technical University, Trabzon, Turkey
Source: Aquaculture Research, Volume 43, Number 8 (July 2012)
Page Numbers: 1065 – 1070
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Abstract: To prevent surface tension-related deaths in horse mackerel larvae, Trachurus mediterraneus, camphor grain (CG; 26 and 52 mg L-1with and without ethanol) and chicken egg white (EW; 40 and 80 µL L-1) were added to rearing water. Compared with the control groups, supplementation of EW (40–80 µL) and CG (52 mg L-1, dissolved in ethanol) significantly improved the survivals of horse mackerel larvae (P<0.05). At the end of the 10 days after hatching, the survival rates of EW-40 and EW-80 were 64% and 72% respectively. No clear correlation was found between surface tension and survival rate.
Citation: Ilhan Yandi, Ilhan Altinok . Prevention of surface death of horse mackerel (Trachurus mediterraneus) larvae by the addition of egg white and camphor grain to rearing water. Aquaculture Research, Volume 43, Number 8 (July 2012), pp. 1065-1070, <http://ejournals.ebsco.com/direct.asp?ArticleID=4BA390FA5ABB2118E41C&gt;
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=4BA390FA5ABB2118E41C
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More emphasis needs to be placed on fish health for the management of marine fisheries.

Perhaps veterinarians can play a leading role in assessing fish health for the purpose of managing marine fisheries.

Reviews in Fisheries Science
Volume 20, Number 3 (July 2012)
Fish Health and Fisheries, Implications for Stock Assessment and Management: The Mediterranean Example
Authors: J. Lloret 1, E. Faliex 2, G.E. Shulman 3, J.-A. Raga 4, P. Sasal 5, M. Muñoz 1, M. Casadevall 1, A.E. Ahuir-Baraja 4, F.E. Montero 4, A. Repullés-Albelda 4, M. Cardinale 6, H.-J. Rätz 7, S. Vila 1, D. Ferrer 1
Author Affiliations:
1: University of Girona, Faculty of Sciences
2: University of Perpignan Via Domitia – CNRS, Centre de Formation et de Recherche sur les Environnements Méditerranéens
3: Institute of Biology of Southern Seas
4: Cavanilles Institute of Biodiversity and Evolutionary Biology, Science Park, University of Valencia
5: USR 3278 CRIOBE CNRS-EPHE, CRIOBE
6: Swedish University of Agricultural Sciences, Department of Aquatic Resources
7: European Commission, Joint Research Centre, Institute for Protection and Security of the Citizen
Source: Reviews in Fisheries Science, Volume 20, Number 3 (July 2012)
Page Numbers: 165 – 180
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Abstract: Although fish health may influence key population-level processes, particularly those dealing with natural mortality, reproduction, and growth, which, in turn, affect stock productivity, little emphasis has been placed on the links between fish health and the management of marine fisheries. This article addresses this gap and illustrates how knowledge of fish health could provide insight for marine fisheries biologists, stock assessment modelers, and managers. The study proposes ways in which the consideration of condition indicators (energy reserves) and parasitism improves stock assessment and fisheries management, especially in situations of data shortage when standard methods cannot be applied, as is the case in many Mediterranean fish stocks. This article focuses on seven case studies of different fish species from the Mediterranean and Black Seas. Overall, and although the relationship between fish health and productivity cannot always be found or quantified, the article emphasizes the importance of the physical health of exploited stocks, particularly during critical life periods of the fish (e.g., prior to spawning, migration, or in the early life stages), as an essential element of sustainable and profitable fisheries. On the basis of these results, stock assessment and fisheries management implications are discussed.
Citation: J. Lloret, E. Faliex, G.E. Shulman, J.-A. Raga, P. Sasal, M. Muñoz, M. Casadevall, A.E. Ahuir-Baraja, F.E. Montero, A. Repullés-Albelda, M. Cardinale, H.-J. Rätz, S. Vila, D. Ferrer . Fish Health and Fisheries, Implications for Stock Assessment and Management: The Mediterranean Example. Reviews in Fisheries Science, Volume 20, Number 3 (July 2012), pp. 165-180, <http://ejournals.ebsco.com/direct.asp?ArticleID=421B8A58189FA7A444C7&gt;
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=421B8A58189FA7A444C7

Nemo faces an acid test in real-life movie sequel.

Townsville-based James Cook University researcher Phillip Munday and his team found clown fish, as well as damsel fish and open-water predators like tuna and spanish mackerel, suffered adverse effects under high acidity.

They said laboratory studies showed increased acid levels affected the main neuro-transmitters in fish brains, causing a malfunction in the sense of smell, hearing and perception of risk, and an increased tendency to stray from safe reef areas.

Read article here…

100 global fish farming standards for salmon aquaculture.

The new standards “will challenge the industry to improve in many areas, and they are one of many tools that must be used to insure the health of the environment, industry and society,”

The Aquaculture Stewardship Council will oversee and accredit the “salmon-auditing process” to approve salmon producers; verification is accomplished by various independent certification bodies worldwide. By passing the audit, producers are approved to use the council’s logo.

Read more…

Oils ain’t oils.

The ornamental fish keepers have been advocating avoiding the use of fats other than those that originate from fish and invertebrates in the diets of their fish. But in the food fish industry, this can be very expensive and so alternatives are being sought. The issue I have with this study is that the trial only goes for 5 weeks and the normal production for the kingfish would be in the vicinity of 2 years. Is growth the only parameter that we should be looking at? What about disease resistance?

Aquaculture
Volume 357, Number 3 (August 2012)
Replacement of fish oil by poultry oil and canola oil in yellowtail kingfish (Seriola lalandi) at optimal and suboptimal temperatures
Authors: J.N. Bowyer, J.G. Qin, R.P. Smullen, D.A.J. Stone
Author Affiliations:
no affiliations available
Source: Aquaculture, Volume 357, Number 3 (August 2012)
Page Numbers: 211 – 222
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Abstract: Fish oil has been replaced by alternative oils to reduce the cost of aquaculture diets, but fish growth may be compromised when fish are fed these oils at suboptimal temperatures. A 5-week feeding trial was conducted to examine the interactive effects of water temperature and the partial or total replacement of fish oil with poultry oil and canola oil on the performance of yellowtail kingfish (YTK, Seriola lalandi), in the early stages of the production cycle. Practical diets were identical in composition, except the dietary lipid component was supplemented with 100% lipid as either poultry oil (PO), canola oil (CO), a blend of fish oil and poultry oil (FO/PO; 50:50) or a blend of fish oil and canola oil (FO/CO; 50:50). A control diet was included and the dietary lipid component contained 100% fish oil (FO). Fish fed the CO diet at 18°C had inferior growth performance, feed efficiency and nutrient retention, and showed higher incidences of green liver and lower plasma cholesterol levels than those fed the other diets. Whole body proximate composition was influenced by water temperature, but not diet, except moisture content which was highest in fish fed CO. The fatty acid composition of fillet lipid correlated with the PO and CO inclusion, in that the proportions of 18:1n-9, 18:2n-6 and 18:3n-6 all increased with increasing dietary PO and CO. The concentrations of 20:5n-3, 22:6n-3 and 20:4n-6 in the fillet lipid were reduced with increasing contents of dietary PO and CO. Our results confirmed that 100% poultry oil and 50% canola oil can replace fish oil in diets without reducing growth, but 100% canola oil results in poor fish growth compared with the FO control, regardless of water temperature. These findings are useful in dietary formulation to reduce feed costs without compromising yellowtail kingfish growth.
Citation: J.N. Bowyer, J.G. Qin, R.P. Smullen, D.A.J. Stone . Replacement of fish oil by poultry oil and canola oil in yellowtail kingfish (Seriola lalandi) at optimal and suboptimal temperatures. Aquaculture, Volume 357, Number 3 (August 2012), pp. 211-222, <http://ejournals.ebsco.com/direct.asp?ArticleID=4F078538461BA51F37FC&gt;
URL: http://ejournals.ebsco.com/direct.asp?ArticleID=4F078538461BA51F37FC

Geriatric goldfish needs this winter.

Very often people think of goldfish as cold water fish. They are in fact, subtropical fish that are tolerant of cold water for periods. The optimal water temperature for this species is in the vicinity of 22-24 degrees Celsius. So, if you find your goldfish are not coping so well this winter, you may introduce a heater and bring the water temperature up slowly at about 1-2 degrees Celsius per day until you reach the optimal temperature. If your fish’s health doesn’t improve, consult your fish vet.