Q: In the spring, why let people keep crappies from bays where they spawn?
A: We in DNR do not have any clear evidence that protecting spawning areas improves spawning success of crappies. We know that anglers fare well in spring when fishing shallow bays, but anglers are also effective at catching crappies during most of the year (look at our winter angling pressure in recent years). Because we continue to see strong year-classes of crappies, we know that anglers do not harvest all spawning crappies. This indicates that only a few successful nests are needed to produce a year-class. I also guess (no real proof) that many of our lakes have limited amounts of spawning habitat, but a surplus of potential spawners. Lastly, crappies can and do spawn when they reach 6 inches in length, lengths that anglers seldom keep. In other words, our crappies have found ways to offset effects caused by spring fishing.
- Response by Mike McInerny, DNR Research Scientist
Q: Is the growing wolf population putting a severe risk on the deer? Should we be concerned?
A: According to the winter 2016-17 wolf survey, the population has shown an apparent, although not statistically significant increase compared to estimates of the preceding several years. At an estimated 2,856 wolves, the population is similar, but still less than the estimate of 2003-04, at 3,020 wolves. We have strong evidence from our long-term study (1990-2005) of survival and cause-specific mortality of 450 radio-collared female deer (including wolves and wolf predation) that at this level, the wolf population does not pose a severe risk to the deer population of the forest zone in northern Minnesota. During winter, when natural mortality of radio-collared does is greatest, even when wolves were at about 3,000, natural mortality was consistently less than 10% annually. Although wolves are the primary source of natural mortality of deer in the forest zone, only a fraction of that 10% was due to wolves. White-tailed deer in the forest zone have such a high reproductive potential, that is, near 95% to 100% pregnancy rates annually, high fertility rates in the females all the way up to at least 15 years of age, and more than half of them produce twins, all of which enables the population to withstand impacts from the primary mortality factors and perform positively, often despite reasonably significant hunting pressure, wolf predation and winter severity.
- Response by Glenn DelGiudice, DNR Research Scientist