Abstract or Keywords
Coastal habitats can sometimes experience more frequent and severe extremes in seawater pH due to nutrient discharge after storm events. The adults of coastal marine species are often able to tolerate changes in environmental conditions like seawater pH, however, their earlier and sometimes more sensitive life-stages (embryos and larvae) are still developing the physiological mechanisms needed to acclimate to those changes. The stone crab, Menippe mercenaria, is an important coastal species throughout south Florida valued at ~$25 million per year. We determined the effects of reduced seawater pH on the stone crab's embryonic development and hatching success. Ovigerous crabs were maintained in a laboratory setting that mimicked present-day and future seawater pH conditions throughout the duration of their embryonic development. The rate of embryonic development was significantly slower (i.e., time to hatching delayed by ~24%) in crabs that were exposed to reduced seawater pH, however, there was no effect on the size of the developing embryos (i.e., embryonic volume ). Stone crab larvae that successfully hatched were not morphologically different between treatments, although the overall hatching success was reduced by 28% in lower pH seawater. The hatching success was also more variable in the acidic treatment indicating that some broods may be more tolerant to changes in seawater acidity. Variable hatching success under extreme seawater pH suggests that stone crab embryos may have the capacity to acclimatize to future seawater pH conditions.