Humans weren’t the only creatures affected by the long, hard winter and cold, wet spring.

The freakish weather patterns also played havoc with the fish community and might explain why anglers are cleaning fish that still have eggs, according to Michigan fisheries biologist Jay Wesley.

In this part of the country, bass typically spawn in late April and into May while bluegill bedding starts in late May and can run into July.

But this is August and some anglers report that they’re still finding fish containing eggs. One angler reported finding eggs in every bass he cleaned from Eagle Lake recently.

Of course, not all fish spawn at once and bluegill have been known to spawn twice in the same summer season. But these bass should have been done with that.

Wesley says that a bass retaining eggs this late in the year is either the result of conditions not being right for that fish to spawn in the spring, or the fish was carrying immature eggs that are in early stages of development for next spring’s spawn.

“If a female bass decided not to spawn because of conditions, she will absorb those eggs and wait until the next year,” Wesley explained. “On the other hand, the eggs could be immature. It’s not uncommon to see females developing eggs this time of year for next year’s spawn.”

Wesley went on to say that fish have an internal mechanism that tells them when to spawn.

Water temperature is a big part of that. Fish depend upon rising water temperatures in the spring to generate egg maturity. If water temperatures warm slowly and the eggs don’t develop adequately, that fish won’t spawn.

“Because of the extended winter, some fish may have used up their fat reserves and their bodies became stressed heading into the spawning season,” Wesley added. “The eggs didn’t develop properly, so their biological sense told them they weren’t physically ready to spawn.”

The spawning rigors can complicate matters for already stressed fish, he said, which in turn can make those fish susceptible to disease.

In fact, a bacterial disease called “Columnaris” has been detected among fish populations in some lakes that have suffered post-winter fish kills this year.

“The disease can be fatal if there are other stress factors going on, such as inconsistent water temperatures while the fish is trying to spawn,” he said. “And, if a lake is getting a weed treatment about the time stressed fish spawn, the disease, coupled with the chemical application, can kill them. We noticed that minor fish kills we investigated this summer occurred about the time chemicals were applied to treat the weeds on that lake.”

Generally speaking, the chemicals used to kill aquatic plants – if applied properly - cause the fish little harm, unless extremely stressed fish are nesting in areas where weeds are being chemically treated.

“Fish came out of the hard winter stressed and went into the spawn with little time to build up their reserves to carry them through the spawn,” explained Wesley. “Weed treatments won’t kill them, but they certainly can be a contributing factor if the fish are stressed.”