The early arrival and ongoing stretch of hot weather is raising concerns about the potential for another fish kill in Brydon Lagoon.
On the August long weekend in 2014, thousands of dead fish were discovered floating on the surface of the lagoon — likely the result of high temperatures and low oxygen levels — and Langley Field Naturalist Rhys Griffiths is concerned that it could happen again.
The fundamental issue, said Griffiths, is the lack of water flowing into the lagoon from two storm sewer pipes on its north side.
With no significant flow into the pond for the past two months, the water level is dropping, noted Griffiths.
Shallow water heats quickly, increasing the threat to the fish.
In addition, Griffiths said, the surface of the pond is once again becoming covered in a large algae bloom, which affects oxygen levels in the water, depleting oxygen at the bottom of the pond and resulting in an over-saturation near the surface.
“Neither condition is good for fish,” he said.
LFN and the City have been working together to fix the problem, but Griffiths is concerned that not enough has been accomplished to prevent another kill if the hot weather continues.
Since last year’s incident, the City of Langley has purchased and installed an underwater bubbler. The pump is attached to hoses which are spread along the bottom of the lagoon and inject air into the water.
“We’ve ordered more hose to get further reach,” said City CAO Francis Cheung.
“It is working, but we want to enhance it even more,” he said.
At the same time, said Cheung, the City is mindful of the noise generated by the lagoon’s aeration pumps, so rather than run them 24 hours a day, they are turned on in the morning and shut off again in the evening, to minimize the disturbance to area residents.
The lagoon supports several species of fish, including carp, sunfish and three-spined stickleback, as well as frogs, newts, salamanders and turtles.
Although most are non-native, much of Brydon Lagoon’s bird life and diversity comes as a result of fish being there, wrote Field Naturalist, Anthea Farr, in a letter to The Times last August.
In an effort to prevent similar catastrophic events to last summer’s fish kill, some have suggested that the City dredge the lagoon — a solution that could cost several million dollars.
“Brydon Lagoon is repeatedly referred to as a ‘jewel’ in Langley’s park system, and is the largest piece of open water for miles around,” said Griffiths.
“We cannot lose it to either neglect or climate change.
“So what to do?”