You guys should read PB mag.
Couple issues back was an article on the subject of LMB growth and forage in the south. I will put parts below then we can discuss.
Actual data from study so you can compare to my text.
Ponds were stocked with bluegills (mean weight 1.4 g) in mid March 2003 at a rate of
3,705 fish ha�1. The bluegill stocking rate was 50% higher than normally recommended
as we attempted to maximize food resources for largemouth bass (Masser
1992). Largemouth bass (mean weight 1.8 g) were stocked into the ponds at the
standard rate of 248 fish ha�1 (Swingle 1950b) in late May 2003, after bluegills had
spawned.
THE CUTTING EDGE � SCIENCE REVIEW
By Eric West
A recent article of interest Population Size, Survival, and Growth of Largemouth Bass One Year After Stocking in Four Ponds by Steve M. Sammons, and Michael J. Maceina, in 2005 Proceedings of the Annual Conference Southeastern Association of Fish and Wildlife Agencies 59:241�250.
I will point out that based on studies like this and their personal observations private fisheries scientist presenters at last year�s Pond Boss Convention recommended stocking small bluegill at 2000 per acre (twice the old stocking rate) in southern largemouth bass ponds to achieve good growth rates.
Notice good growth rates not trophy LMB. The use of the word trophy in the study refers to Anderson Wr and condition indices not 10lb LMB. Note Proportional Stock Density (PSD). Three new size categories - preferred, memorable, and trophy - were developed to accompany previously established stock and quality lengths.
Due to the high bluegill stocking rate (150% of the normal suggested rate), largemouth bass presumably had an abundant food supply. The relatively low density of largemouth
bass, coupled with an assumed unlimited food supply, allowed these fish to forage at close to maximum rates, leading to rapid growth and high condition or relative
weight.
Bioenergetic models estimated that the largemouth bass population in these ponds consumed between 132 and 171 kg ha (roughly 150 lbs per acre) of bluegills in the first 300 days after stocking to maintain the observed growth.
Each population of largemouth bass was predicted to have consumed 4.2 to 6.7 times their own biomass in bluegills in 300 days to maintain these growth rates and biomass. Recent research has revealed consumption-dependent error in many bioenergetic models, including the one used in this study, which was particularly large when growth rates were fast .
Thus, the percent of maximum consumption by largemouth bass estimated in this study were likely underestimated which probably indicates that the bluegill densities in the ponds used in this study may not be great enough to meet predator demand in the future, leading to slower growth, poorer condition, and a possibly lower production of trophy-sized fish. The fact that the high consumption rates of largemouth bass found in this study were probably underestimated serves as warning of how delicate predator-prey balances are in small ponds, and
how easily predator demand can exceed prey supply if predator densities are not strictly controlled . One of the most common themes on the Pond Boss Forum is overabundant largemouth bass in ponds. This study plus current recommendations of 2000 stock size bluegill per acre appear to be a remedy for the tendency of southern ponds to quickly (2 to 3 years) get bass crowded.
Actual text :
Thus, the P-value and
consumption by largemouth bass estimated in this study were likely underestimates,
which may indicate that the bluegill densities in the ponds we used in this study may
not be great enough to meet predator demand in the future, leading to slower growth,
poorer condition, and a possibly lower production of trophy-sized fish.Subsequent year classes of largemouth
bass in these systems are not likely to exhibit the fast growth observed in this study,
as largemouth bass densities increase (Irwin et al. 2003).
However, the fact
that the high consumption rates of largemouth bass found in this study may have
been underestimates serves as warning of how delicate predator-prey balances are
in small ponds, and how easily predator demand can exceed prey supply if predator
densities are not strictly controlled (Geihsler and Holder 1983).
This was in fertilized ponds with small stocker fish BG (1500 per acre) in March followed by LMB (100 per acre) in late may after the BG had spawned. Results were fast initial growth in LMB with the forage base being overeaten if viewed in terms of continued ability to sustain the pond. Other studies upon which this one relied showed in older ponds up to 1.5 X LMB per acre with diminished forage and slow growth.
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