Environment

Invasion of the midges

Millions of midges are flooding lakeside suburbs across Perth, inconveniencing businesses and residents.

Attracted to light, dense swarms of the non-biting insects have flown in from wetlands to nearby houses and businesses in Perth’s north and south.

Surge Fitness in Wanneroo has had issues with the insects since opening early last year.

The fitness centre, at the corner of Wanneroo Road and Joondalup Drive, backs onto Lake Joondalup.

Surge Fitness manager Marc Fury says the number of midges making their way inside the property was out of control, putting people off visiting the gym.

“Around this time of year it gets extremely bad at night,” Mr Fury says.

“Our landlord made a few complaints to the council, but we’re yet to see much of an improvement this year.”

City of Wanneroo director of business Chris Morrison says midges have been a problem since areas near Lake Joondalup were developed.

“The City of Wanneroo and the City of Joondalup receive many complaints about the midges at this time of year,” he says.

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Entomologist at the WA Museum, Nikolai Tatarnic, says midges are common after winter because Perth’s lakes are full of nutrients from winter storm runoff.

“The runoff carries phosphorous and nitrogen from fertilisers, which in turn feeds algae in lakes and streams,” he says.

“High nutrients are associated with more food for midge larvae and therefore higher midge numbers.”

Mr Morrison says the City of Joondalup, City of Wanneroo and the Department of Parks and Wildlife have formed a midge management agreement which lays down a “balanced approach” to the insect issue.

“We are mindful that Lake Joondalup is an important wetland ecosystem,” he says.

“Chemical treatment is only undertaken as a last resort in response to high larvae numbers, the location of swarms and the number and type of complaints.”

He says chemical treatments may not work if they are used too often.

“Over time midges may gain resistance to the larvicide used to treat larvae and future treatments may not be effective,” he says.

Surge Fitness receptionist Kylie Donley says working at night is challenging because of complaints from members.

She says members are “disgusted” at the swarms of midges that come inside the club.

“There’s really not much we can do,” she says.

“Sometimes we close the automatic doors completely and direct members through another exit to try and reduce the amount [of midges] coming inside.”

Dr Tatarnic says although midges are a pest they do not carry disease.

“They are non-biting flies which belong to the Chironomidae family,” he says.

“However, some people who are prone to allergic reactions may react from exposure to midges.”

A City of Cockburn spokeswoman says midges are widespread around lakes in Perth’s southern suburbs.

“The city has treated some lakes such as Yangebup Lake with larvicide, distributed by helicopter,” she says.

“Chemicals are always used as a last resort because it can harm wildlife living in or near the wetland.”

Dr Tatarnic says areas near lakes may experience issues with midges lay their eggs in water and the larvae grow and live on the lake sediment.

“The clutches of eggs are attached to floating debris and hatch in one or two days, releasing about 800 larvae,” he says.

“The whole life cycle can range from just three weeks to a little over a month, but they need to be near water to survive.”

Joondalup resident Amy Heslop says the midges are “a pain” and have stopped her family from enjoying the outdoors.

“Sometimes we just want to sit outside … or walk our dog but it’s not very pleasant because the midges are everywhere,” she says.

Dr Tatarnic says that unlike other lakes Lake Joondalup does not dry significantly until the end of summer so it never loses its midge population.

He says that using yellow external lights, and keeping indoor lights away from windows can minimise midge numbers around the home.

Categories: Environment, Health

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