https://www.sciencenews.org/article/...oped-out-ducks

Quote Originally Posted by Science News
For fish eggs, getting gobbled by a duck kicks off a harrowing journey that includes a pummeling in the gizzard and an attack by stomach acids. But a few eggs can exit unscathed in a duckís excrement, possibly helping to spread those fish, including invasive species, to different places, a new study finds.

Itís been an ďopen question for centuries how these isolated water bodies can be populated by fish,Ē says fish biologist Patricia Burkhardt-Holm of the University of Basel in Switzerland, who was not involved with the work. This study shows one way that water birds may disperse fish, she says.

Birdsí feathers, feet and feces can spread hardy plant seeds and invertebrates (SN: 1/14/16). But since many fish eggs are soft, researchers didnít expect that they could survive a birdís gut, says Orsolya Vincze, an evolutionary biologist at the Centre for Ecological Research in Debrecen, Hungary.

In the lab, Vincze and her colleagues fed thousands of eggs from two invasive carp species to eight mallard ducks. About 0.2 percent of ingested eggs, 18 of 8,000, were intact after defecation, the team found. Some of those eggs contained wriggling embryos and a few eggs hatched, the team reports June 22 in the Proceedings of the National Academy of Sciences. Itís not clear yet whether eggs survive in this way in the wild.

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