Native fish species at risk following water removal from the Colorado River

December 12, 2017

Agriculture and domestic activities consume much of the Colorado River water that once flowed to the Colorado Delta and Northern Gulf of California. The nature and extent of impact of this fresh-water loss on the ecology and fisheries of the Colorado Delta and Gulf of California is controversial. A recent publication in the journal PeerJ reveals a previously unseen risk to the unique local biodiversity of the tidal portion of the Delta.

Unique ecological species evolved in the historically fresher Colorado Delta and adapted to this environment. These fish are distinct from closely related species in the historically saltier estuaries found in other regions of the Gulf. However, the Colorado Delta is now more similar in salinity to many of the other estuary systems in the Gulf of California, suggesting that the ecological factors that separated species may have broken down.

Workers from UCLA examined species of silverside fish in a genus that only occurs in the Gulf of California. One species, Colpichthys hubbsi, lives exclusively in the Delta and is listed as endangered due to its restricted range. Morphologic and genetic anayses demonstrate that this species hybridizes along the western edge of the Delta with Colpichthys regis, a widespread relative distributed in estuaries throughout the Gulf. Although hybrids could be recognized morphologically, there was no evidence of hybridization in earlier museum collections.

Furthermore, the genes from the widespread species were found to penetrate the range of the Delta specific species, but there were no genes from the Delta species found elsewhere in the Gulf. Thus, there was clear evidence of gene movement in one direction between the two species. This potentially places the Delta species at risk of extinction as its genome is swamped or replaced by the genes of the other species.

In this particular case, more work is needed to clarify the detailed causes of species separation and the nature of ongoing impacts to the genome of the Delta species. However, there are broader issues at stake than a single species. Other groups of fishes and crabs also appear to have evolved as ecological species restricted to the Colorado Delta. These may also be at risk. More broadly, water extraction continues to accelerate in large river systems around the world. Thus, loss of ecological species in deltas and estuaries around the world is also likely accelerating.

Museums and institutions in Mexico, including the Los Angeles County Museum of Natural History, Scripps Institution of Oceanography CIAD in Guaymas facilitated this work by sharing their collections and supporting field work.
-end-
Image:

Image caption: Jars of preserved fish specimens from the Scripps Institution of Oceanography used in this study. Photo Credit: Clive Lau. Usage restrictions: None.

Full Media Pack including image: https://drive.google.com/open?id=12Y9PhI3_wp3k7Mn4klb8yfLhAwnRE1ij

EMBARGOED until 12 December 2017: 7 am EST; 12 pm UK time (i.e. the date of publication)

PDF of this Press Release: http://static.peerj.com/pressReleases/2017/12/Press-Release-Jacobs.pdf

Link to the Published Version of the article (quote this link in your story - the link will ONLY work after the embargo lifts): https://peerj.com/articles/4056 your readers will be able to freely access this article at this URL.

About:

PeerJ is an Open Access publisher of two peer-reviewed journals and a preprint server. PeerJ's mission is to help the world efficiently publish its knowledge. All works published by PeerJ are Open Access and published using a Creative Commons license (CC-BY 4.0). PeerJ is based in San Diego, CA and the UK and can be accessed at peerj.com

PeerJ is the peer-reviewed journal for Biology, Medicine and Environmental Sciences. PeerJ has recently added 15 areas in environmental science subject areas, including Natural Resource Management, Climate Change Biology, and Environmental Impacts. peerj.com/environmental-sciences

PeerJ has an Editorial Board of over 1,900 respected academics, including 5 Nobel Laureates. PeerJ was the recipient of the 2013 ALPSP Award for Publishing Innovation. PeerJ Media Resources (including logos) can be found at: peerj.com/about/press

Media Contacts

David Jacobs
djacobs@ucla.edu

For PeerJ: email: press@peerj.com , https://peerj.com/about/press/

Note: If you would like to join the PeerJ Press Release list, please register at: http://bit.ly/PressList

PeerJ

Related Genes Articles from Brightsurf:

Are male genes from Mars, female genes from Venus?
In a new paper in the PERSPECTIVES section of the journal Science, Melissa Wilson reviews current research into patterns of sex differences in gene expression across the genome, and highlights sampling biases in the human populations included in such studies.

New alcohol genes uncovered
Do you have what is known as problematic alcohol use?

How status sticks to genes
Life at the bottom of the social ladder may have long-term health effects that even upward mobility can't undo, according to new research in monkeys.

Symphony of genes
One of the most exciting discoveries in genome research was that the last common ancestor of all multicellular animals already possessed an extremely complex genome.

New genes out of nothing
One key question in evolutionary biology is how novel genes arise and develop.

Good genes
A team of scientists from NAU, Arizona State University, the University of Groningen in the Netherlands, the Center for Coastal Studies in Massachusetts and nine other institutions worldwide to study potential cancer suppression mechanisms in cetaceans, the mammalian group that includes whales, dolphins and porpoises.

How lifestyle affects our genes
In the past decade, knowledge of how lifestyle affects our genes, a research field called epigenetics, has grown exponentially.

Genes that regulate how much we dream
Sleep is known to allow animals to re-energize themselves and consolidate memories.

The genes are not to blame
Individualized dietary recommendations based on genetic information are currently a popular trend.

Timing is everything, to our genes
Salk scientists discover critical gene activity follows a biological clock, affecting diseases of the brain and body.

Read More: Genes News and Genes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.