Testicular microlithiasis occurs in more than 5% of healthy young men. In contrast, testicular cancer develops in 3/100,000 to 5/100,000 men or 1,000-fold less often. The relative prevalence of testicular microlithiasis with respect to testicular cancer, increased prevalence in minorities, bilateral distribution, and inverse geographic distribution of men with testicular microlithiasis and testicular cancer represent evidence against an association of the 2 conditions. This study indicates that testicular microlithiasis is a common finding in asymptomatic men that may not be related to testicular cancer.

Testicular microlithiasis occurs in more than 5% of healthy young men. In contrast, testicular cancer develops in 3/100,000 to 5/100,000 men or 1,000-fold less often. The relative prevalence of testicular microlithiasis with respect to testicular cancer, increased prevalence in minorities, bilateral distribution, and inverse geographic distribution of men with testicular microlithiasis and testicular cancer represent evidence against an association of the 2 conditions. This study indicates that testicular microlithiasis is a common finding in asymptomatic men that may not be related to testicular cancer.

Studies that evaluate the effects of different feeding strategies (e.g., feeding frequency and food type) on larval fish growth and survival are important for aquaculture productivity. We quantified the effects of common feeding strategies on the growth and survival of larval Lake Sturgeon Acipenser fulvescens. At 30 d after initiation of exogenous feeding, the TL and body weight of larvae reared under a treatment regime of three feedings per day (TL [mean ± SE] = 46.83 ± 0.43 mm; body weight = 0.41 ± 0.01 g) were significantly greater than those of fish reared under a regime of 12 feedings per day (TL = 45.73 ± 0.54 mm; body weight = 0.39 ± 0.02 g). Alternate food type and family were documented to have significant effects on the body weight of hatchery‐produced larvae at 14 d postexogenous feeding: body weight was significantly greater for larvae that were fed brine shrimp Artemia spp. (family 1 [mean ± SE]: 0.31 ± 0.004 g; family 2: 0.35 ± 0.006 g) than for larvae that received formulated food (family 1: 0.06 ± 0.006 g; family 2: 0.08 ± 0.014 g). Furthermore, alternate food type had a significant effect on the survival of hatchery‐produced larvae at 14 d postexogenous feeding, as survival was greater for larvae that were fed Artemia (97.0 ± 3.0%) than for those that were given formulated food (34.0 ± 7.0%). In addition, alternate food type had significant effects on the body weight and survival of wild‐caught Lake Sturgeon larvae, with both variables being greater for fish that received Artemia (body weight [mean ± SE] = 0.41 ± 0.02 g; survival = 94.0 ± 2.0%) than for fish that were given formulated food (body weight = 0.03 ± 0.01 g; survival = 17.0 ± 6.0%). Our results provide guidance to direct feeding strategies that can be used to develop standard operating procedures for the culture of Lake Sturgeon, a species of conservation concern.

Summary Knowledge of the effects of environment and genotype on behavior during early ontogenetic stages of many fish species including lake sturgeon (Acipenser fulvescens) is generally lacking. Understanding these effects is particularly important at a time when human activities are fundamentally altering habitats and seasonal and diel physical and biotic stream features. Artificial stream channels were used in a controlled experiment to quantify lake sturgeon yolk‐sac larvae dispersal distance and stream substrate preference from different females (N = 2) whose eggs were incubated at different temperatures (10 and 18°C) that simulated stream conditions during early and late spawning and incubation periods in the Black River, Michigan. Data revealed that yolk‐sac larvae exhibited considerable variability in dispersal distance as a function of family (genotype), temperature experienced during previous (embryonic) ontogenetic stages, and environmental ‘grain’. Yolk‐sac larvae dispersal distance varied as a function of the juxtaposition of substrate to location of egg hatch. Lake sturgeon yolk‐sac larvae dispersed from mesh screens attached to bricks and settled exclusively in gravel substrate. Dispersal distance also varied as a function of family and egg incubation temperatures, reflecting differences in offspring body size and levels of endogenous yolk reserves (yolk sac area) at hatch. Expression of plasticity in dispersal behavior may be particularly important to individual survival and population levels of recruitment contingent upon the location, size, and degree of fragmentation of suitable (gravel) habitats between adult spawning and yolk‐sac larvae rearing areas.