Study of feeding behaviors points to challenges for native fish

Feb 03, 2012
Populations of the roundtail chub have greatly declined in recent decades, and the results of a recent NAU study suggest that human-caused conditions favor nonnative species of fish found in the Colorado River.

( -- A study detailing the feeding behaviors of four species of fish found in the Colorado River and its tributaries uncovered a few surprises and opened new insights to the challenges faced by native fish species in the Southwest.

Some of the biggest challenges are relatively recent ones. In a diverse region known for its markers of geologic time, a combination of dam building and the introduction of have dramatically reduced the survival chances of native fish, said Northern Arizona University researcher Alice Gibb.

A biology professor, Gibb is the corresponding author of a new paper, “Prey Capture Behavior of Native vs. Nonnative Fishes: A Case Study from the Drainage Basin (USA),” that appears in the Journal of Experimental Zoology A.

That native fish in the Southwest are on the decline is not in dispute, but the research provides more evidence as to why.

“We altered the habitat native fish evolved for and put in fish that are better-adapted to the new conditions,” Gibb said, calling the changes a “one-two punch” for native fish.

For the study, Gibb and her colleagues compared the native roundtail chub with the nonnative smallmouth bass, and the native Sonora sucker with the nonnative common carp—species that occupy the same “ecological niche.”

While Gibb expected the nonnatives to consume everything offered to them, the study found that it was the native fish that had a broad diet in the lab. The nonnatives were choosier.

“I would interpret the native feeding as opportunistic behavior,” Gibb said. But it’s a behavior that evolved in the constantly changing habitat of the Southwest in warm, turbid water. The nonnatives, Gibb said, are from more stable and clear conditions—just like those created by the introduction of dams.

Gibb also noted that the nonnatives have bigger mouths. “That’s going to provide an advantage, especially when it comes to eating other fish,” she said. Smallmouth bass, for example, can eat chub—but not the other way around—and they have a better chance of doing so in clear water.

“The research results suggest that it’s the conditions that favor the nonnatives,” Gibb said.

Considering that those conditions are human caused, the findings have implications for wildlife management.

“You can try to extirpate the nonnatives,” Gibb said, noting an environmental restoration of Fossil Creek that has created a reservoir habitat for . “But people want their sport fish, which are good predators in clear conditions.”  

Such dynamics are not the case only in the Southwest. Gibb said there is growing worldwide interest in a field known as “invasion ecology.”

“It’s an area that’s recently been recognized as a tool to understand why some species go extinct and others take over.”

Explore further: Man 'expelled from Croatia for punching monk seal'

Provided by Northern Arizona University

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Fish jump into picture of evolutionary land invasion

Oct 06, 2011

( -- Research sometimes means looking for one thing and finding another. Such was the case when biology professor Alice Gibb and her research team at Northern Arizona University witnessed a small ...

Can we bring the grayling back to Michigan?

Aug 16, 2011

( -- Overfishing and destruction of its habitat have driven the Arctic grayling from its native Upper Michigan waters. But Michigan Technological University biologists Nancy Auer and Casey Huckins ...

Native species proposed as viable long-term sequesters

Jan 26, 2012

( -- New research into the carbon sequestration abilities of native tree species was undertaken by Greening Australia, and will hopefully make native species more attractive and viable option for ...

Weeds and the Murray

Feb 15, 2011

( -- A new study has revealed that human-induced changes in the flow of the Murray River has led to mass weed invasion and reduced biodiversity in wetlands along the riverbank, highlighting the need for a review ...

How fish swim: Imaging device shows contribution of fins

Apr 22, 2011

There are fish tales and then there are fish tails. And a report from Harvard researchers in the current issue of the journal Biology Letters seems to demonstrate that previous theories about how bony fish mo ...

Recommended for you

Brother of Hibiscus is found alive and well on Maui

6 hours ago

Most people are familiar with Hibiscus flowers- they are an iconic symbol of tropical resorts worldwide where they are commonly planted in the landscape. Some, like Hawaii's State Flower- Hibiscus brackenridgei- are en ...

Boat noise impacts development and survival of sea hares

8 hours ago

While previous studies have shown that marine noise can affect animal movement and communication, with unknown ecological consequences, scientists from the Universities of Bristol and Exeter and the École Pratique des Hautes ...

Classic Lewis Carroll character inspires new ecological model

Jul 30, 2014

Inspired by the Red Queen in Lewis Carroll's Through the Looking Glass, collaborators from the University of Illinois and National University of Singapore improved a 35-year-old ecology model to better understand how species ...

Saving seeds the right way can save the world's plants

Jul 30, 2014

Exotic pests, shrinking ranges and a changing climate threaten some of the world's most rare and ecologically important plants, and so conservationists establish seed collections to save the seeds in banks ...

User comments : 0