Featured Research

from universities, journals, and other organizations

New Chemical Method For Distinguishing Between Farmed And Wild Salmon

Date:
October 1, 2009
Source:
National Oceanography Centre, Southampton (UK)
Summary:
Wild salmon and farmed salmon can now be distinguished from each other by a technique that examines the chemistry of their scales.

Wild salmon and farmed salmon can now be distinguished from each other by a technique that examines the chemistry of their scales.
Credit: Image courtesy of National Oceanography Centre, Southampton.

Wild salmon and farmed salmon can now be distinguished from each other by a technique that examines the chemistry of their scales.

Dr Clive Trueman, who is based at the National Oceanography Centre, Southampton said: "Salmon farming is a big, intensive business. In 2006, around 130,000 tonnes of salmon were farmed in Scotland for the table. Wild populations of Atlantic salmon are in serious decline across their whole range and the total wild population returning to Scottish rivers in the same year is estimated at less than 5000 tonnes. Wild fish are rare and expensive so there is a strong incentive for fraudulent labelling. Farmed fish also escape into rivers, harming the wild population. Unfortunately, it can be difficult to distinguish between farmed and wild fish."

The new work which was done in collaboration with the Scottish Association for Marine Science (SAMS), Oban, will help crack this problem.

Fish scales are formed from the same chemicals as bones and teeth and grow like tree rings, preserving a chemical record of the water the fish lived in throughout its whole life. Scales are easy to collect, and can be removed from fish without harming them – which is important when studying an endangered population. The team discovered that levels of the trace metal manganese were always much higher in fish of farmed origin.

"This is probably caused by manganese supplements in fish food, and also because conditions underneath the fish cages promote recycling of manganese in the water column," says Dr Elizabeth Adey from SAMS, lead author on the research.

Using relatively simple techniques, the team was able to distinguish between farmed and wild fish with 98% accuracy.

"Because of its non-destructive nature, this technique could be used to assess the proportion of farm escape salmon present in any river, and therefore identify where additional conservation and wildlife protection measures are needed," says Dr Trueman, a geochemist with the University of Southampton's School of Ocean and Earth Science, based at that National Oceanography Centre.

Concern over declining numbers of wild Atlantic salmon has led to the closure of most fisheries, and the growth of salmon farms has been implicated in the decline of the wild fish. In 2000, more than 400,000 fish escaped from farms in Scotland. This is a problem as farmed salmon are not adapted to the local environment, and if they breed with the wild stock, the resulting offspring are less likely to survive to adulthood. In some years, the number of fish that escape from farms in Scotland exceeds the total number of wild fish, and in some Norwegian rivers more than half of all fish are of farmed origin.

It is particularly difficult to distinguish between a farm origin and wild origin fish if some time has passed after the fish escaped, and that is why the new method should prove valuable.

The team also found differences in the chemistry of scales between fish farms, which might allow researchers to identify individual farms responsible for the release of wild fish – although this would require additional work.

The research was supported by the UHI Millennium Institute.


Story Source:

The above story is based on materials provided by National Oceanography Centre, Southampton (UK). Note: Materials may be edited for content and length.


Journal Reference:

  1. Adey et al. Scale microchemistry as a tool to investigate the origin of wild and farmed Salmo salar. Marine Ecology Progress Series, 2009; 390225 DOI: 10.3354/meps08161

Cite This Page:

National Oceanography Centre, Southampton (UK). "New Chemical Method For Distinguishing Between Farmed And Wild Salmon." ScienceDaily. ScienceDaily, 1 October 2009. <www.sciencedaily.com/releases/2009/09/090930102530.htm>.
National Oceanography Centre, Southampton (UK). (2009, October 1). New Chemical Method For Distinguishing Between Farmed And Wild Salmon. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2009/09/090930102530.htm
National Oceanography Centre, Southampton (UK). "New Chemical Method For Distinguishing Between Farmed And Wild Salmon." ScienceDaily. www.sciencedaily.com/releases/2009/09/090930102530.htm (accessed September 22, 2014).

Share This



More Plants & Animals News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins