Q: I have many friends that fish, and we just got back from a weekend at Melvern fishing and camping, where we caught quite a few crappie. I fielded many questions, but I do not know if my answers were all correct. Like ... At what water temperature do the male crappies start to establish the nest sites? When do the females move in to spawn. Is it temperature- or daylight-controlled? What will the rise or fall in the water do? What about the rise and fall of the barometer? Has the length limit helped out the population? I have my own ideas on the answers, but would love to hear what a professional thinks.
A: All of the individual crappie do not react the same. This spreads the spawn over a longer period and helps insure the survival of the species as well as the individual populations. From what I see, the males start moving in shallow at about 55 degrees, and this increases until the peak of about 60-65 degrees. It appears that the larger females come in first at about 60 degrees but don't spend much time on the nest. They hang out in a little deeper water and then come in and spawn and leave. The males stay on the nest to protect the eggs. It does not take many spawning crappie to produce a strong year class if conditions are right.
The spawn is triggered by daylight length and temperature. The spawn in Kansas started early this year because of record-high temperatures in early April. Rising water levels can improve the survival of the young by increasing habitat and food supply. Falling water can work the opposite and even leave eggs stranded. That is why we try to have water level management plans on lakes. Cold fronts sometimes move the fish back into deeper water and can delay spawning. I am not sure just how they react to the barometer; the rise and fall of air pressure is usually the result of a front that also changes water temps. Crappie will spawn at different depths according to water clarity. It maybe less than a foot to more than five feet in Kansas.
The length limit probably has no impact on the crappie population on a long-term basis as survival of the crappie population is concerned. It does keep the crappie in the lake until they reach a quality size, and this increases catch rates for the anglers and provides them with larger fish. We actually have a program that we can estimate the impact, and this shows us that there is about a two- to five-pound-per-acre-per-year increase in harvest potential by having the length limit. That equates to a lot of pounds of crappie in a 7,000-acre lake such as Melvern. So from an angler's perspective, yes, it does improve the crappie population at Melvern.