Naturespeak 

Millars Pond dilemma

Whistler Naturalist Society

Millars Pond in Bayshores can be considered a healthy and productive wetland, but for the uninvited guest which is steadily threatening its overall health. Carassius auratus, the common goldfish, was released into Millars Pond sometime in 2002 by a fool with either good intentions or malicious intent.

Goldfish are related to Carp ( Cyprinus carpio) . They can survive in many different habitats where temperatures are high and oxygen levels are low, such as plastic bags and glass bowls in the window. Millars Pond is absolutely heaven with its abundance of aquatic vegetation, muck bottom and warm temperatures. Millars Pond also provides a plentiful diet of insect larvae, some of which are the largest and healthiest seen in Whistler. Goldfish are voracious eaters with no manners. They are known to stir up muck and silt while they are digging for the roots of their favourite plants. This increased cloudiness wouldn’t be a real issue if there was only one fish but next to eating, the favourite pastime for goldfish is spawning. Each spawning pair can lay up to 10,000 eggs and sometimes spawn more than once a year. They will grow up to 40 cm with the average being between 12 and 22 cm. Once goldfish are born in the wild, their colour is a dull, olive-grey.

The main local residents being inconvenienced by C. auratus are the amphibians. Beautiful Northwestern Salamanders ( Ambystoma gracile) have been seen in Millars Pond. In higher elevations such as Whistler, it is common for this large salamander to reach sexual maturity in the pond and spend their entire life under water.

Another amphibian known to breed in Millars Pond is the Pacific Chorus Frog ( Pseudacris regilla ) formerly named the Pacific Treefrog. These species will be extremely vulnerable to changes in the environment brought on by the habits of the goldfish. The increase in sediments in the water will not only clog their gills, but will suffocate the insects they rely on for food. With that, the voracious feeding habits and tolerance for poor water quality of the goldfish will eventually force our native species away, including the plants and waterfowl.

It is always wrong to release a non-native species. Many popular exotic pets such as fish, birds and mammals, not to mention exotic plants, have shown a great ability to survive and flourish in our climate. The resilience to local limiting factors and lack of predators creates a real problem for controlling the invaders.

The fish in Millars Pond were not reported for at least two years and in that time seven fish became about 350 fish. Millars Pond is linked to the Millar Creek wetland complex north of Function Junction. There have been no successful trappings or sightings as of yet, however, they will be impossible to control should they be found there.

Anyone interested in volunteering to help trap the goldfish or assist in the monitoring of Millars Pond please call Veronica Woodruff at 604-935-8323.

Upcoming Events:

The Whistler Naturalists will hold the season’s first nature walk on Wednesday, May 4th, 6:30-8:30 p.m., at Nairn Falls Provincial Park. Stéphane Perron will be the walk leader and the walk will start at the park parking lot. There is no charge and the public is welcome. But this season, each person who participates will be asked to sign a registration and waiver form.

This walk is rated as "easy" and should be suitable for all family members.

Pacific Rim's Annual Mother's Day Weekend Sale Saturday and Sunday, May 7-8, 10 a.m. to 4 p.m. This is your chance to stock up on Trillium, fawn lilies, tiger lilies and many native perennials, vines, groundcovers and trees. Directions on website: www.hillkeep.ca

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