|11/10/2017 7:26:00 AM|
The lake where you live
Approaches to spawning
By Ted RulsehFor most of us, fishing isn't top of mind during these in-between days before the ice firms up. Meanwhile, the fish in our lakes are half a year from spawning, but let's explore one interesting facet of that behavior, anyway.
It turns out that there are two basic types of spawners: broadcasters and nesters. The broadcaster females drop their eggs more or less at random on the bottom, and the males follow and shed their milt in the same somewhat imprecise manner.
Nesters, as the name implies, fan out nest sites on the bottom. The females deposit their eggs there and the males shed their milt on that spot. It is much more targeted and efficient, in addition to which the nesters patrol the site for a while to protect the young against predators.
Steve AveLallemant, a retired Wisconsin DNR fisheries experts, observes, "Broadcast spawners in general are prolific reproducers but lousy parents - unlike nest building species, which lay fewer eggs but guard them relentlessly."
In other words, fish that guard their young don't have to produce as many to sustain the species, because the little ones' survival odds are better (though still rather grim). Both broadcasters and nesters lay thousands of eggs at a time. For example, a five-pound female walleyes may deposit more than 100,000 eggs in a single spawning episode; a smallmouth bass lays up to 14,000.
Walleyes of course are broadcast spawners, depositing their eggs soon after ice-out over rocky or gravely bottom. Once they spawn, they leave, and the kids are on their own. Bass (largemouth and smallmouth) are nesters, fanning out circular nests two to four feet in diameter, also in gravely areas. The popular panfish - bluegills, sunfish, rock bass and crappies - are also nesters, and the males of these species guard the nests aggressively; crappies may even, at first, chase away females coming in to spawn.
Perch, on the other hand, are broadcasters, though they don't spread their eggs in quite as random a fashion as some others. The females discharge them in jelly-like strands that hang from sunken branches or other solid objects. Northern pike are broadcast spawners, dropping their eggs on shallow-water vegetation. The hatchlings' worst enemies are members of their own kind; they face high mortality from cannibalism. Muskies do their broadcasting in slightly deeper water and a couple of weeks later.
Among the nesters, bullheads are perhaps the most attentive parents. Both the male and female defend the nest before the eggs hatch. The young travel in schools, and the male stays with them until they're about an inch long, herding strays and stragglers back into the group.
So clearly, in the fish world, there's more than one way to raise a family.
Ted Rulseh, who lives on Birch Lake in Harshaw, is the author of the "The Lake Where You Live," a blog where readers can learn about the lakes they love - the history, geology, biology, chemistry, physics, magic, charm. Visit lakewhereyoulive.
blogspot.com. Ted may be reached at firstname.lastname@example.org.
Article Comment Submission Form