Bass International, one of the country's premier bass fishing tournaments was
held this past weekend on Lake of the Woods
and to say that at least some of the fish were mixed up and acting weirdly is
of the continent, Northwestern Ontario has
been shaking and baking this summer under scorchingly hotter than normal
conditions. Indeed, the water
temperature in many of the massive million acre lake's shoreline shallows and
backwater bays has exceeded 80 F or 27 C for much of the summer. So why in the world were anglers finding and
catching smallmouth bass this weekend on beds?
right. Nesting summer smallmouth.
general rule, smallmouth bass spawn in the spring as soon as water temperatures
approach 60 F / 16 C in temperature.
And, according to Ontario Ministry of Natural Resources scientist Dr.
Mark Ridgway, the biggest fish spawn first.
past two decades, Ridgway has headed up a team of biologists working out of the
Harkness Laboratory of Fisheries Research in Algonquin Provincial
Park. His work on the smallmouth bass of Lake Opeongo
has contributed to the longest continuous census of any animal population on
earth. It’s approaching 80 years worth
of data. Ridgway's findings have also shed
new light on the factors that determine the reproductive success and year class
production of smallmouth bass in northern lakes and rivers.
Ridgway’s most significant discoveries, for example, is the fact that northern range
smallmouth don't spawn for the first time until they are between five and nine
years of age and between 10 inches and 16 inches in length. More importantly, precisely when a smallmouth
lays its eggs or guards a nest is based on the size of the fish. As a general rule, large males and females
spawn earlier in the spring than their smaller brothers and sisters. This difference is hugely important for
reasons we’ll see in a minute.
Ridgway’s most astonishing finding, though, is the revelation that only about
one-third of all the smallmouth bass big enough to spawn in a northern lake
actually reproduce in any given year.
Even more amazing, the factors that determine which bass will comprise
the one-third spawning group are established during the previous summer.
(Northern range smallmouth bass use the summer to feed voraciously and gain weight to survive the winter starvation period. So why in the world are they nesting in August?)
means,” says Ridgway, “is that if you pull a bass off a nest there is no rush
of new fish waiting to move in. Once the
spawning decision is made, it is absolutely final. Pull a male off his nest and no one else will
says Ridgway, if the population of larger smallmouth is angled down, smaller
bass must be rushed to the front … ahead of their time … to assume the spawning
chores in subsequent years. But smaller
bass spawn later than larger fish. This
fact holds true even when they are the only nesters left in the lake.
that when fall arrives, the young-of-the-year that the small bass produce are
at a distinct disadvantage in terms of surviving the winter starvation
period. In the north, for all intents
and purposes, bass don’t eat once a lake freezes. As a result, young-of-the-year smallmouth
must eat and grow fast enough in the first year of their life … typically to
the size of your little finger … to survive to the following spring. So every
day they’re delayed in the egg-laying stage is another potential nail in their
coffin. Still, it can get worse.
you force small bass to start spawning ahead of their time,” Ridgway explains,
“because you’ve ratcheted down the big bass population, their reproductive life
span becomes only one or two years. Like
the young-of-the-year, they starve to death during the winter. These smaller nesting bass, typically 12
inches or so, have a very high mortality rate.
It is the cost of reproduction.
Very few of these fish survive to reproduce twice. But, as nesters increase in size, up to
seven, eight, nine plus years of age, you get a much higher return rate. These older fish do not pay a survival price
in terms of reproduction like the smaller fish do."
to Ridgway the odds of north country bass surviving the first year of their
lives are about the same as playing Russian Roulette. It’s a game, by the way, southern bass don’t
have to play.
to Ridgway, the best possible scenario occurs when the ice leaves northern
lakes early in the spring, water temperatures warm up quickly and large
genetically fit fish nest ahead of schedule.
If "freeze up" in the fall is then delayed and warm summer
conditions are extended it is even better still. And if the following spring arrives early once
again, it is the best of all possible worlds for the fish.
that is precisely what happened way back in 1983 and 1984 when conditions
meshed together perfectly to produce the biggest bass year class most biologists
have ever seen.
all the stars line up perfectly is rare.
More often, says Ridgway, you can have a wonderful spawn, and then see
all the gains you thought you made in the summer, wiped out over the winter.
brings us back to the conditions on the weekend. Given that the water temperature in Lake of the Woods long ago reached and then super
exceeded the 60 F temperature that normally sparks smallmouth to spawn, why
were large males nesting in August?
Surely any young of the year that might hatch at this late stage will be
too small to survive the winter starvation period. And the "cost of reproduction" to
the adults must be fatal as well.
least one of the anglers, OFAH's Mike Miller, says he and his partner have caught
smallmouth spawning in the same area during KBI in previous years as well.
a suicidal life-style strategy.