Migrating fish leave behind a trail of DNA

DNA analysis revealed the presence of migrating fish species in New York's Hudson and East rivers. Photo by Rockefeller University

April 16 (UPI) — Wherever fish go, they leave behind traces of DNA. As new research shows, scientists can track fish migrations by following their trail of DNA.

Researchers at Rockefeller University sequenced DNA from water samples collected daily in New York’s East and Hudson rivers. Their analysis — detailed in the journal PLOS ONE — revealed the presence and absence of a variety of local fish species as they traversed the river.

The presence and absence of specific species corresponded with migration patterns established by previous net surveys.

“For the first time, we’ve successfully recorded a spring fish migration simply by conducting DNA tests on water samples,” Rockefeller researcher Mark Stoeckle said in a news release.

Researchers identified the genetic signatures of 42 fish species among the sampled DNA. The amount of genetic material corresponded to the expected abundance of local species. Only a few surprise species were identified.

“We didn’t find anything shocking about the fish migration — the seasonal movements and the species we found are known already,” said Stoeckle.

That means the technique is accurate. Because the method is cheap and easy, researchers believe it has great potential. However, scientists say more testing and comparisons with previous surveys are necessary.

“If future research confirms that an index of species’ abundance can be derived from naked DNA extracted from water, it could easily improve the rationality with which fish quotas are set, and the quality and reliability of their monitoring around the world,” said Jesse Ausubel, director of Rockefeller’s Program for the Human Environment.


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