Can Nemo Find His Way Home?

May 3, 2007
Can Nemo Find His Way Home?
The orange clownfish is one of two species studied by Michael Berumen and his colleagues. The fate of ocean fish larvae has remained a mystery to science until now, but Berumen and his colleagues have used a novel technique to directly explore their journey from egg to adult for the first time. Credit: University of Arkansas

The fate of ocean fish larvae has remained a mystery to science until now, but a University of Arkansas researcher and his colleagues have used a novel technique to directly explore their journey from egg to adult for the first time. Their findings, which also may help governments and marine organizations better manage marine protected areas, appear in the May 4 issue of the journal Science.

Michael Berumen, a postdoctoral researcher at the University of Arkansas, and his colleagues Glenn R. Almany and Geoffrey P. Jones of James Cook University in Australia, together with Simon R. Thorrold of Woods Hole Oceanographic Institution and Serge Planes of the University of Perpignan, France, examined the dispersion of two species of coral reef fish larvae on a small, isolated island near Papua New Guinea.

"The fate of fish larvae has been a major question for marine ecologists," said Berumen. Researchers know that fertilized fish eggs become larvae with an ability to swim, and they remain in the larval stage anywhere from one week to almost two months. The big question is, where are they during this time? And do they return to the reef where they were spawned?

The researchers attempted to answer these questions by injecting small amounts of signature barium isotopes into female fish of two species: The orange clownfish, a brightly colored specimen made popular by the movie Finding Nemo, and the vagabond butterflyfish, which is white with black, yellow and blue markings. Both are found in coral reef populations in the South Pacific. The barium isotopes enter the bloodstream of the female fish and finally end up in the eggs that she disperses. This barium signal remains with the "tagged" larval fish as they grow into juveniles, settling in the otolith, an ear bone found in fish.

Berumen and his colleagues tagged 176 clownfish females and 123 butterflyfish on a coral reef surrounding Kimbe Island near Papua New Guinea. They chose the two species because each one reproduces in a different way and their larval stages differ in length: Clownfish spend less than two weeks in the larval stage, while butterflyfish spend over a month at that stage. The scientists returned to the island about one month after the initial tagging and collected 15 juvenile clownfish and 77 juvenile butterflyfish. They then examined the barium composition of the otoliths using mass spectrometry.

The results showed that about 60 percent of the juveniles from each species developed from larvae that originated on the reef.

"So if we were to answer the question: Can Nemo find his way home? In this case, it looks like about 60 percent of the time he can," Berumen said. "It's also important to note that we estimate that 40 percent of the juveniles came from other reefs - at least six miles away across open ocean - so we can also confirm that these populations are ecologically connected."

"If this result is typical, appropriate scales for management may be smaller than previously realized," Berumen said. This study suggests that the design of marine protected areas should be small-scale to both be able to sustain the reef, yet also populate reefs outside of the protected area, the researchers write.

Source: University of Arkansas

Explore further: Potential for Saudi Arabian coral reefs to shine

Related Stories

Potential for Saudi Arabian coral reefs to shine

May 1, 2017

Marine surveys estimating fish population density and diversity are crucial to our understanding of how human activities impact coral reef ecosystems and to our ability to make informed management plans for sustainability. ...

The first genome of a coral reef fish

September 30, 2016

Sequencing the genome of an organism allows scientists to investigate its unique genetic make-up, its evolutionary links to other creatures, and how it has adapted to its environment. Researchers at King Abdullah University ...

Butterfly fish 'may face extinction'

February 25, 2008

A beautiful black, white and yellow butterflyfish, much admired by eco-tourists, divers and aquarium keepers alike, may be at risk of extinction, scientists have warned.

Nemo can't go home

August 20, 2013

Round the planet the loveable clownfish Nemo may be losing his home, a new scientific study has revealed.

Recommended for you

Archaeologists find ancient necropolis in Egypt

February 24, 2018

Egypt's Antiquities Ministry announced on Saturday the discovery of an ancient necropolis near the Nile Valley city of Minya, south of Cairo, the latest discovery in an area known to house ancient catacombs from the Pharaonic ...

AI and 5G in focus at top mobile fair

February 24, 2018

Phone makers will seek to entice new buyers with better cameras and bigger screens at the world's biggest mobile fair starting Monday in Spain after a year of flat smartphone sales.

Researchers turn light upside down

February 23, 2018

Researchers from CIC nanoGUNE (San Sebastian, Spain) and collaborators have reported in Science the development of a so-called hyperbolic metasurface on which light propagates with completely reshaped wafefronts. This scientific ...

Walking crystals may lead to new field of crystal robotics

February 23, 2018

Researchers have demonstrated that tiny micrometer-sized crystals—just barely visible to the human eye—can "walk" inchworm-style across the slide of a microscope. Other crystals are capable of different modes of locomotion ...


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.