Discovering lost salmon at sea

June 23, 2011
Co-author William Beaumont of the Game and Wildlife Conservation Trust holds a large male salmon. Credit: (Credit: © Anton Ibbotson)

Where Atlantic salmon feed in the ocean has been a long-standing mystery, but new research led by the University of Southampton shows that marine location can be recovered from the chemistry of fish scales. Surprisingly, salmon from different British rivers migrate to feed in separate places, and may respond differently to environmental change.

Numbers of Atlantic salmon have declined across their range since the early 1970s, and most researchers believe that conditions experienced at sea are largely to blame. Unfortunately, identifying where salmon go to feed in the huge expanse of the North Atlantic is difficult as attaching artificial tags to fish is expensive. A paper published this week in Scientific Reports shows that fish carry natural records of feeding location hidden in the chemistry of their scales.

The chemistry of reflects the composition of food and water in the area where they live and feed, and can act as a natural tag. Using this idea, the Southampton team, working with scientists from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), the Game and Trust (GWCT) and the National Oceanography Centre (NOC), looked at the contained in historical records of scales of . The scales grew while the salmon were feeding at sea, so the values of the scales reflect the values of their diet in the feeding grounds. The team compared the scale values through time with satellite records of across the North Atlantic. The locations of sea where the time series match best are most likely to be the areas where the fish have been feeding.

"As every single salmon contains the natural chemical tag, we can now see where fish from individual rivers go to feed in the Atlantic," lead author Dr Kirsteen MacKenzie said. "Interestingly, we found that salmon born in two areas of the British Isles swim to feeding grounds that are far apart, and experience very different conditions while at sea". Co-author Dr Clive Trueman continued: "This information allows for better management of individual fish populations by monitoring both environmental conditions and fishing efforts in the areas where they feed". "Our technique can also be used to aid conservation of animals such as turtles, seabirds and tuna, and identify the best areas for marine protection measures," added Dr MacKenzie.

Explore further: Farmed salmon could become an invasive species in forest streams

Related Stories

The bear necessities of aging

December 12, 2007

According to George Bernard Shaw: “We don’t stop playing because we grow old; we grow old because we stop playing,” but how fast does that aging occur once started" In the case of populations of salmon in Alaska studied ...

Salmon fishing season at risk in Calif.

March 13, 2008

U.S. officials are considering canceling the 2008 salmon fishing season in California and Oregon because of a dramatic decline in salmon population.

Study Reveals Genetic Secrets Of Pacific Sea Louse

April 1, 2009

(PhysOrg.com) -- Sea lice found in the Pacific Ocean are very different genetically from sea lice in the Atlantic Ocean, a study team co-led by a University of Victoria researcher has found.

Recommended for you

Studies reveal details of error correction in cell division

July 29, 2015

Cell biologists led by Thomas Maresca at the University of Massachusetts Amherst, with collaborators elsewhere, report an advance in understanding the workings of an error correction mechanism that helps cells detect and ...

Researchers discover new type of mycovirus

July 29, 2015

Researchers, led by Dr Robert Coutts, Leverhulme Research Fellow from the School of Life and Medical Sciences at the University of Hertfordshire, and Dr Ioly Kotta-Loizou, Research Associate at Imperial College, have discovered ...

Stressed out plants send animal-like signals

July 29, 2015

University of Adelaide research has shown for the first time that, despite not having a nervous system, plants use signals normally associated with animals when they encounter stress.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.