Fewer male pike in fish habitat

[Spiel]

Fewer male pike in fish habitat

Chemical outflow on the hook

 

 

December 10th, 2008

Rob Faulkner / Hamilton Spectator

 

 

Cootes Paradise is famous for a habitat restoration effort that includes barring carp from this 250-hectare wetland at the west end of Hamilton Harbour.

 

But also for vanishing male pike.

 

In a disturbing echo of recent news about gender-bending chemicals, a Royal Botanical Gardens aquatic biologist says male northern pike are hard to find.

 

At the fishway, a carp barrier at the mouth of the harbour credited with saving the marshland, only 27 pike per year pass through. (About 500 pike live in a cleaner system called Hendrie Valley.)

 

But at the fishway, crews found that about 77 per cent of the pike are female.

 

“We do know we have a serious problem,” said acting head of conservation Tys Theysmeyer. Also, in 2003, he took females and males to a clean pond and they failed to produce baby pike.

 

“We did it a second year and it didn’t work. So we said, ‘OK, they look like males but aren’t behaving like males,’” adds a man jokingly called a pike matchmaker.

 

The observations come amid news that chemicals in food wrapping, makeup and baby powders are feminizing males, in wildlife and in human populations. Communities polluted with the chemicals are reportedly giving birth to twice as many girls as boys.

 

Theysmeyer says a serious source of chemical outflow into Cootes is the Dundas wastewater treatment plant, which he says pumps out so much nitrogen fish eggs can’t hatch near the sewage-outflow pipe into Desjardins Canal.

 

At times, treated sewage is nearly the only water in the canal squeezed between Cootes Drive and King Street East.

 

A key scientific paper on local fish and gender effects from chemicals was by a graduate student at Trent University, Theysmeyer said.

 

A 2003 masters of science thesis by Richard Kavanagh found male white perch from Cootes Paradise had a high prevalence (83 per cent) of intersexualism (male and female traits). This trend, called “gonadal intersex,” has been observed in wild fish in areas with domestic and industrial effluent.

 

The rate in Cootes was much higher than in male white perch in in eastern Ontario’s Bay of Quinte (22 to 44 per cent) and the Windsor area’s Lake St. Clair (45 per cent).

 

Cootes perch were exposed to high levels of endocrine-disrupting substances, which may be responsible for gonadal intersex, the Kavanagh paper concluded.

 

Theysmeyer said likely solutions to the dearth of male northern pike will include upgrades to the Dundas water treatment plant, or better treating the water.

 

But stopping the sewage plant’s outflow isn’t wise when it provides a steady stream into the canal, where mature fish return to spawn.

 

“In the summer, when it rains, all we are left with (in the canal running to the Dundas marsh) is parking lot runoff,” he says, highlighting the need of water from the plant.