Fish Hormones Change When Oxygen Is Scarce. (Sexual Hang-Up)

By Morgan, K. | Science News, March 1, 2003 | Go to article overview
Save to active project

Fish Hormones Change When Oxygen Is Scarce. (Sexual Hang-Up)


Morgan, K., Science News


Oxygen deprivation tampers with sex hormones in fish and impairs reproduction, according to new research. The results suggest that low oxygen in freshwater ecosystems can disrupt animals' endocrine systems. Researchers say this link might explain the ongoing decline in some fish and amphibian species.

Various pesticides, components of plastics, and other chemical pollutants known collectively as endocrine disruptors mimic natural hormones such as estrogen. Scientists have linked such contaminants to reproductive failures in many animals and to oddities ranging from deformities in frogs to sex changes in fish. The disruptors are also suspected of underlying some breast cancer in women.

Researchers have found that other physical factors--including artificial lighting and magnetic fields--can similarly disrupt hormones (SN: 7/3/93, p. 10). Now, Rudolf S.S. Wu of the City University of Hong Kong and his colleagues add oxygen deficiency, or hypoxia, to the list of endocrine disruptors.

Human activities that overload fresh water with plant nutrients, such as components of fertilizers and detergents, reduce concentrations of dissolved oxygen in lakes and rivers. Wu and his colleagues found earlier that oxygen-starved fish have an altered metabolism and remain smaller than normal. The team wondered whether the almost suffocating conditions might also stunt fish reproduction.

To find out, the team placed immature adult carp--a species unusually tolerant of hypoxia--in lab conditions of either normal or one-seventh normal oxygen concentrations for 12 weeks.

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
Loading One moment ...
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited article

Fish Hormones Change When Oxygen Is Scarce. (Sexual Hang-Up)
Settings

Settings

Typeface
Text size Smaller Larger
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

While we understand printed pages are helpful to our users, this limitation is necessary to help protect our publishers' copyrighted material and prevent its unlawful distribution. We are sorry for any inconvenience.
Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.

Are you sure you want to delete this highlight?