Lake Scugog walleye population dwindling
Natural causes, over-fishing blamed by MNR
The number of walleye in Lake Scugog has dropped dramatically in recent years, a dip government fishery officials attribute to both over-fishing and natural causes.
When the Ministry of Natural Resources began tracking the walleye population in Lake Scugog during the 1970s, it's estimated that as many as 20,000 of the fish were harvested during one open-water season alone.
That figure dropped significantly in the early 1980s, to an estimate of about 5,000, before rebounding to between the 10,000 and 15,000 range from the mid-1980s to about 1999.
From there, however, the estimated harvest took a significant dip, falling to just below 5,000 fish caught in 2007, a figure that remained steady through 2011.
Ice-fishing figures follow a similar pattern, with the MNR estimating around 14,000 fish harvested in 2004 before falling to barely more than 1,000 in 2011.
On average, about a third of all walleye harvested from Lake Scugog are caught during the winter ice-fishing season, which spans January and February.
"The decline has been significant, it has been measurable," said Mike Rawson, who works with the MNR's Kawartha Lakes Fisheries Assessment Unit.
"Our long-term information indicates a decline and more recent information indicates a reduction in abundance," he said. "The overall pattern is decline."
Walleye are not native to Lake Scugog. They were introduced to the lake about 50 years ago, according to Mr. Rawson, and became a popular target for anglers in the 1970s.
About three-quarters of anglers throughout the Kawartha Lakes and Ontario, as well as across Canada, fish for walleye.
But as the stock in Lake Scugog continues to drop, Mr. Rawson is left with no concrete answers for their disappearance, just contributing factors.
He estimates the current Lake Scugog walleye population hovers around 6,000. About 40 per cent of them will die in a year, through either natural causes or fishing.
"Certainly 40 per cent is on the high side and that's reflected, connected with significant fishing," said Mr. Rawson.
According to MNR estimates, summer anglers on the hunt for walleye collectively spent just over 40,000 hours on Lake Scugog in 2011. During that year's ice-fishing season, anglers fished for about 20,000 hours.
About every four years, the MNR conducts angler surveys, which includes counting the number of fishermen on the lake, asking where they're from and checking out what has been caught.
On average, it takes about 3.3 hours to catch one walleye. As a rule of thumb, the MNR looks at it as 0.3 walleye are caught each hour.
Through eight surveys over recent years, the majority of times anglers reported catching 0.2 walleye per hour.
In 2011, that figure dropped to 0.14.
"There are still people coming for them, but it's not a very robust fishing experience," said Mr. Rawson.
Judi Parsons, who co-owns Causeway Live Bait with her husband Dave, is a little skeptical of the MNR's numbers.
"They are catching them, just not hand over fist. But they are getting them," she said of walleye fishing on Lake Scugog this year. "I haven't gotten any complaints."
Ms. Parsons expects this walleye season, which started in mid-May, to be a decent one given the dismal ice-fishing season, which was stunted due to unseasonably warm temperatures and generally unsafe ice conditions.
She said most anglers are reporting catching fair-sized walleye as they gear up for the upcoming bass season, which opens June 23.
"They're keying in on the walleye," said Ms. Parsons.
But another key contributor in walleye population decline, continued Mr. Rawson, is the low abundance of both older, mature fish as well as younger fish.
"There are a diminished number of older fish and that is the fingerprint of exploitation," said Mr. Rawson. "The population does reflect the high level of harvesting."
Another factor in the dwindling walleye numbers can be connected to the arrival of zebra mussels in the late 1990s, added Mr. Rawson. In most lakes where zebra mussels appear, the clarity of the water improves, sometimes by as much as a metre.
While the transparency of Lake Scugog's water hasn't improved that significantly, Mr. Rawson said there is a clear pattern: Clearer water equals more weeds which leads to fewer walleye.
"Zebra mussels are one factor," he said.
Mr. Rawson also points out that Lake Scugog in general is not a habitat preferred by walleye, mostly due to the fact the lake does not offer the species their favoured type of spawning grounds.
"It's certainly not a typical walleye lake," he said. "The spawning habitat is not what you would find in a textbook."
But Mr. Rawson is quick to stress it's unlikely the local walleye population will disappear.
"With things being what they are, there should not be anything that forces them to extinction," he said.
One factor that could help the walleye population, he added, is the booming bass industry.
Recent statistics "show clearly that people are not targeting walleye for fishing like they used to" and that there is currently a "social trend" towards bass, said Mr. Rawson.
It's unknown, however, if that's due to dipping walleye numbers or the explosion of interest in bass.
"The walleye population could be better. The bass are very healthy," he said.
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