Sex Of Sea Lamprey Is Determined By Its Growth Rate

Posted: Mar 30 2017, 2:05am CDT | by , Updated: Mar 30 2017, 3:04am CDT, in News | Latest Science News

Sex of Sea Lamprey is Determined by its Growth Rate
Credit: Visuals Unlimited/Corbis

Sea lampreys, an invasive, parasitic species of fish could become male or female depending on how quickly they grow

Sea lampreys are eel-shaped fish that use their mouth to attach and feed on the blood and fluids of other fish. They are most primitive of all 46,000 known species of vertebrates, meaning that these bloodsucking creatures are least changed over time.

Now, researchers have discovered that they have yet another surprising distinction. After taking a closer look at growth rate, researchers have found that the sex of sea lamprey is not determined at birth. Lampreys become male or female depending on how quickly they grow, making them the first creatures known to undergo sex determination in this way. Slower growth rate during the larval phase increases their odds of becoming male while more conductive environment for growth results in more female production.

Since sea lamprey is an invasive, parasitic species of fish that invaded the Great Lakes in late 1820s, their colonies are threatening to upset the local ecological balance. However, the discovery could lead to new ways of controlling sea lamprey populations.

“Remarkably, we don’t set out to study sex determination in sea lampreys – we were planning to study environmental effects on growth rates only,” said Nick Johnson, a USGS scientist and the lead author of the study. "We were startled when we discovered that these data may also reveal how sex is determined because mechanisms of sex determination in lamprey are considered a holy grail for researchers.”

Researchers know next to nothing about sex determination in sea lampreys - until now. Between 2005 and 2007, a team of researchers tagged and released sea lamprey larvae into both unproductive lakes and productive streams, including the lakes of Huron and Michigan. The researchers then recaptured the tagged lamprey and checked their sex after the larvae had morphed into adults and migrated during spawning period.

Researchers found that lampreys started out with undifferentiated sexual organs as larvae. But after a year or so, they transformed into either male or female. Lampreys in productive streams with lots of food available reached maturity earlier and were more likely to be female while unproductive sites were dominated by male lampreys.

Sea lampreys are native to Atlantic Ocean, but they invaded the Great Lakes after the construction of the Welland Canal in 1829, causing destruction to native fish populations. According to estimates, one lamprey kills about 40 pounds of fish every year and cost US fisheries billions of dollars a year.

“The results of this study could be a critical step toward developing advanced technologies to control sea lampreys in the Great Lakes, which have caused unparalleled damage to fisheries," said David Ullrich from Great Lake Fishery Commission. "Although sea lamprey populations have been reduced by 90 percent, innovation will be key to maintaining strong control into the future. The results of this study could open paths forward to novel technologies that can disrupt or modify gender in sea lampreys, providing the commission with other means to control this noxious predator.”

The findings of the study were published in The Royal Society Publishing.

This story may contain affiliate links.


Find rare products online! Get the free Tracker App now.

Download the free Tracker app now to get in-stock alerts on Pomsies, Oculus Go, SNES Classic and more.

Latest News


The Author

<a href="/latest_stories/all/all/47" rel="author">Hira Bashir</a>
The latest discoveries in science are the passion of Hira Bashir (). With years of experience, she is able to spot the most interesting new achievements of scientists around the world and cover them in easy to understand reporting.




comments powered by Disqus