This is followed by a rapid redeposition of salvaged inorganic salts to harden the new cuticle. Tissue water is replaced with protein during the next intermolt period. Blue crabs cease feeding and seek out shelter and isolation from non-molting conspecifics as ecdysis approaches. A lunar rhythm of molting has been observed. Intermolt periods increase with age of blue crabs, but are generally shortened by ample food availability, high dietary nutrient quality and high water temperatures.
Small crabs molt frequently with molt frequency decreasing as carapace width increases.
Larger crabs are often found in areas of low salinity, suggesting a negative correlation of size with salinity. Laboratory studies evaluating the effects of salinity on growth of blue crabs, however, have yielded conflicting results. Males become sexually mature at the 18 or 19th molt but may continue to grow and molt an additional 3-4 times thereafter. Female crabs were initially thought to rarely, if ever, molt again following their pubertal molt. However, mature females undergoing a second molt have been verified.