Featured Research

from universities, journals, and other organizations

Seafood: 'Ray' wings sold to consumers include vulnerable species and can be mislabeled

Date:
August 13, 2013
Source:
PeerJ
Summary:
Genetic testing by DNA Barcoding, has revealed which species are sold under the commercial term "ray wings" in Ireland and the UK. The blonde ray, given the lowest rating for sustainability in the marine conservation society's good fish guide, was the most widely sold. Samples from the only retailer to label products as originating from more sustainable sources demonstrated high levels of mislabeling, substituted by more vulnerable species. Therefore, consumers cannot make informed purchasing decisions.

This image shows some of the species of skate sold for consumption, these beautiful fish fish, with their characteristic flattened body are adapted for life on the sea bed.
Credit: Andrew Griffiths

Genetic testing by DNA Barcoding, has revealed which species are sold under the commercial term 'ray wings' in Ireland and the UK. The blonde ray, given the lowest rating for sustainability in the marine conservation society's good fish guide, was the most widely sold. Samples from the only retailer to label products as originating from more sustainable sources demonstrated high levels of mislabelling, substituted by more vulnerable species. Therefore, consumers cannot make informed purchasing decisions.

The research was conducted at the University of Salford and University College Dublin, as part of an international project called "LabelFish" that is currently investigating seafood labelling and traceability within the European Union (EU). The study, titled "DNA Barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in 'ray' products sold across Ireland and the UK" was published today in PeerJ.

The lead author of the paper, Dr Andrew Griffiths, explained the motivation behind the work -- "the commercial title 'ray' is really an umbrella term that includes a large number of fish that are scientifically known as 'skates', a relative of the sharks. These skates are valued for their large fins or wings, so their bodies are usually discarded and they are skinned before sale, making it impossible to identify what species are being sold." He went on to explain that "many of the largest growing species of skate have undergone massive declines in abundance, becoming locally extinct for large parts of their former range. In response the European Union has prohibited the landing of some of the most endangered species and requires closer monitoring of landings of all skates. We wanted to investigate exactly which species are being passed on to consumers."

This work, inspired by a pioneering study in New York conducted by two high school students who analysed samples of sushi, also involved several undergraduates (who are listed as co-authors on the article and were supervised by Prof Stefano Mariani) to collect samples and conduct DNA barcoding on them. DNA barcoding is now a relatively straightforward process which allows rapid and robust species identifications to be made by using a single short sequence of DNA, meaning it is a great tool for students to investigate food authenticity and mislabelling.

The findings showed that none of the ray wings analysed originated from endangered species that were prohibited from being landed in the EU. This is good news for the conservation of groups of skate that are of most critical conservation concern. However, the results were not all positive; the most commonly identified species in the study was the blonde ray (Raja brachyura), a large-growing species that has a decreasing population trend and which the marine conservation society (MSC) awards its lowest sustainability rating, suggesting consumers should avoid purchasing it. In fact, size has previously been suggested as a good proxy for risk to overfishing, and the blonde ray was just one of three large growing species identified during investigations. All three are associated with declining abundance and concerns over sustainability.

The study concludes that the use of ambiguous or amalgamated sales terms makes it impossible for consumers to exercise the right to choose species of lesser conservation concern helping to protect these declining species. Dr Griffiths added that "currently there is a dichotomy; the EU generally requires skates to be identified to the species level when landed, but this information is not being passed onto consumers. This remains a real obstacle in allowing consumers to make informed choices." Interestingly, some supermarket chains have already made commitments to supply smaller growing species that are viewed as more sustainable. One retailer even went as far as labelling its ray wings as originating from these smaller growing groups. Analysis of a limited number of wings purchased from this supermarket showed a third were mislabelled; they really belonged to a more vulnerable larger growing species. This highlights the importance of on-going efforts to improve labelling of foods, not only to protect consumers, but also to allow informed choice and promote the conservation of vulnerable species.


Story Source:

The above story is based on materials provided by PeerJ. Note: Materials may be edited for content and length.


Journal Reference:

  1. Andrew Mark Griffiths, Dana D. Miller, Aaron Egan, Jennifer Fox, Adam Greenfield, Stefano Mariani. DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in ‘ray’ products sold across Ireland and the UK. PeerJ, 2013; 1: e129 DOI: 10.7717/peerj.129

Cite This Page:

PeerJ. "Seafood: 'Ray' wings sold to consumers include vulnerable species and can be mislabeled." ScienceDaily. ScienceDaily, 13 August 2013. <www.sciencedaily.com/releases/2013/08/130813101822.htm>.
PeerJ. (2013, August 13). Seafood: 'Ray' wings sold to consumers include vulnerable species and can be mislabeled. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2013/08/130813101822.htm
PeerJ. "Seafood: 'Ray' wings sold to consumers include vulnerable species and can be mislabeled." ScienceDaily. www.sciencedaily.com/releases/2013/08/130813101822.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
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