Pond Boss Forums INTRO Questions & Observations Carrying capacity

I was wondering whether the morts were female or male. The lengths are consistent with managing for higher population and slow/moderate growth (depending on perspective, to a person that wants trophies, that is slow, to a person who wants balance, that is just right). Females growing by ad libitum consumption could make the average weights of the morts in just a couple of years. Sometime ago I was trying to understand how RW plays into all of this. Fish in the range of 95 and 110 appeared consistent with fish growing at around 25-30% of maximum potential. Those fish were growing (average for their age) at 27% of potential in a Goodland, KS climate. They very well could have marked better growth than that earlier in life stalling over the past few years. FWIW, RW is highly variable and can swing all over the place for fish of all the varying potential of average annual growth. Don't use a RW of 100 to conclude a fish is growing by 25% of its potential.

Just a theory ... but here goes with some background. I think the marking of length increment is important for survival. In the Texas 17 year study that Eric introduced me to, the survivors almost all recorded length increment. The exceptions were explained by damage to fins cause by spawning activities. Morts were not part of the growth data, but this suggests that survivors do have length increments. Length increments even occurred in the rare years that there were declines in average weights. In years where there were declines in average weights, these were high mortality years. So growth may in some way be important to an individual's fish prospects of survival. In the Texas study, the fast growers demonstrated they had a higher rate mortality. But as they grew, the separation of the weights of fast and slow grower declined. What this means is that the rate of growth of slow growers eventually overtakes the rate of growth of fast growers. Fast growers rate of growth stalled sooner than the slow growers.

Fast growers have really good initial growth but eventually divide between the fast growers and the slow growers becomes too broad to benefit equally from forage production. For two LMB to grow at the same percentage gain, they need to consume similar proportions of their body weight. Because the fast grower weighs more, the consumption required is proportional to the ratio of the weight of the fast grower to the slow grower. Each only has one mouth and each are afforded a similar number of opportunities for whatever prey is present. But the slow grower has an advantage. Its optimum sized prey is smaller than the fast grower and so unless the prey starts at a size that is more optimum for the larger fish ... the smaller fish always maintains a competitive advantage (here I am talking adult LMB > 3 yrs age ... not fingerling or adolescents). A smaller LMB can grow at a density of prey that the larger LMB cannot. Keep in mind that as a cohort of prey grow, their population density declines. So, as an LMB grows larger, the availability of consumable prey eventually falls below the density required to maintain its weight.

I think this is in part why fast growers die younger. They stop growing earlier than the slow growers do. Perhaps, something internal accelerates end of life when growth stops. To be sure, such fish forage more frequently without success and undergo more stress than fish that are growing. Don't know for sure but growth seems to be an important contributor to the rate of survival.