Check out this recent paper:
Verner-Jeffreys DW, Baker-Austin C, Pond MJ, Rimmer GSE, Kerr R, Stone D, et al. Zoonotic disease pathogens in fish used for pedicure [letter]. Emerg Infect Dis [serial on the Internet]. 2012 Jun.
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) | |||||||||||||||||
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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 | ||||||||||||||||
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| Source: | Reviews in Fisheries Science, Volume 20, Number 3 (July 2012) | ||||||||||||||||
| Page Numbers: | 165 – 180 | ||||||||||||||||
| Available Full Text: |
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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> | ||||||||||||||||
| 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.
Should the ice slurry method be used to euthanase fish?
I had put a few posts in the past about recommended methods for fish euthanasia.
I was alarmed when I came across this article that was published only as recently as 2010 in the Journal of Fish Biology –
Humane killing of fishes for scientific research: a comparison of two methods. In the abstract it concluded that ice-slurry immersion was more humane than benzocaine overdose and that it should be accepted as a standard humane method for the species used and for other warm-water species. But when you read the paper, there are a few things I have major reservations about.
One of the opening statements was –
The aim was, therefore, to compare the behavioural stress response and the associated time taken to lose equilibrium and reach the death endpoint by a small to medium bodied Australian freshwater Clupeid bony bream (Nematolosa erebi),…..
Anyone who deals with anaesthesia should be aware that there are planes of anaesthesia and that the “excitatory phase” is one of the planes of anaesthesia. It’s not a behavioural stress response. It can be avoided by using higher doses of anaesthetic so that this phase can be shortened or “bypassed”. Behavioural stress response is not an adequate measure to come to such a conclusion. Heart rate and cortisol levels are some of the methods we could be using.
The paper also states the reason why several other authors have found disfavour with the ice slurry method:
The traditional method of immersing fish in an ice-slurry to achieve death by hypothermia relies on lowering the core body temperature resulting in anaesthesia and subsequent death. This has been approved by some fish euthanasia guidelines (Barker et al., 2002), but rejected by others (e.g. European Commission, DGXI – Working Party, 1996; Barker et al., 2002; Reilly et al., 2001; European Commission, DGXI – Working Party, 1997). Rejections of the method have been based firstly, on evidence that the method potentially causes an initial period of discomfort due to ice crystal formation both on the skin and within the body (Reilly et al., 2001), and secondly on a potentially long treatment time before achieving death (Van De Vis et al., 2003) because of the poor thermal conductivity of tissues surrounding the brain (European Commission, DGXI – Working Party, 1996).
It sounds like the authors found good evidence to suggest that the ice slurry method should be aborted, but chose to discount the evidence.
The paper goes on to say…
It should be noted, however, that studies of the use of ice-slurry for fish slaughter (in the food industry) have often been undertaken on large cold-water species from the Northern Hemisphere, such as turbot (Psetta maxima), gilt-headed sea bream (Sparus auratus) and Atlantic salmon (Salmo salar) (Van De Vis et al., 2003; Morzel et al., 2003). Current Australian guidelines are based on these northern hemisphere studies (Reilly et al., 2001), but it is not clear if such assumptions are universally valid, particularly for small to medium bodied, warm-water fish.
According to fishbase, the Australian freshwater Clupeid bony bream (Nematolosa erebi) is a subtropical species and has a preferred water temperature range of 15 – 25 degrees Celsius. Subtropical fish should by no means be considered “warm-water fish”. Its tolerance range is not shown on the database but I’d expect it to be much lower than this.
In conclusion,
- I would not support the ice slurry method of fish euthanasia.
- I am appalled that this paper passed the peer review process to become published.
- It pays to read the article in its entirety to check out its methodology before believing.
I shall dismount from my high horse now and get back to more menial tasks that I have to do today.
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.
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) | |||||||||||||||||
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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 | ||||||||||||||||
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| 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> | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=4F078538461BA51F37FC | ||||||||||||||||
Mental health check.
It’s that gloomy winter time again and we should be keeping ourselves well and looking out for our neighbours.
Check out these useful sites on mental health:
Australian Veterinary Association
Reach Out for the youth.
Please share this information with your family, friends and colleagues.
Temperature changes should be gradual.
Following on from my last post about goldfish preferring the warmer water and people rushing out to buy a heater, I should add that any changes should be done gradually. See also attached, a page from my recently published book (orders can be made via my website – http://www.thefishvet.com.au) about temperature.
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.
Benefits of touch pools.
Check out the latest post on my Facebook Fanpage.