Study: Dead Zones Cause Sex Changes in Fish

New research indicates that polluted run-off might be causing reproduction problems for ocean fish by making more males than females. The GLRC’s Lester Graham reports:

Transcript

New research indicates that polluted run-off might be causing
reproduction problems for ocean fish by making more males than
females. The GLRC’s Lester Graham reports:


Rivers dump much of the pollution and agricultural runoff they carry into
the oceans. That often causes a dead zone… an area where the oxygen is
depleted. New research being published in the journal, Environmental
Science & Technology, indicates low levels of oxygen can cause sex
changes in embryonic fish. That’s leading to an overabundance of
males.


The lead researcher, Rudolf Wu at the City University of Hong Kong
finds since there are a lot more males… it’s less likely the males fish will
find females to reproduce. That means there might not be enough new
fish to maintain sustainable populations.


Some dead zones develop naturally, but scientific evidence suggests that
often dead zones are caused by fertilizers used on farmland crops
running off into rivers and finally into the oceans.


For the GLRC, this is Lester Graham.

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