Blue crabs (Callinectes sapidus) are decapods found in estuaries across the Western Atlantic.
They regulate the abundance of organisms within ecosystems and contribute millions of
dollars to fishing industries around the United States. Unfortunately however, there have been
reported decreases in Blue crab populations, and mature individual sizes. Furthermore, blue
crab habitats, like estuaries, are becoming warmer and more acidic due to climate change.
This experiment sought to determine if increasing temperatures and acidity of estuarine
environments, can negatively impact blue crab juveniles, by simulating these conditions in a
laboratory setting. We collected 180 crabs from the Neuse Estuary in Beaufort, North
Carolina and placed them into 3" finger bowls. Then they were placed into two incubators,
one set at 24°C and the other at 28°C. Each temperature treatment also included three pH
treatments (i.e., 6.5, 7.5, and 8.5) with 30 individuals per treatment. We monitored
development for nine weeks, and recorded crab intermolt duration and molt sizes daily.
Results/Conclusions
We found that juveniles in the warmer, acidic treatment had significantly smaller molts than their
cooler, non-acidic counterparts. We also found that juveniles coped with thermal stress by
taking longer to molt. Crabs with smaller shells are more susceptible to predation and females
have reduced fertility. Over time, these effects will reinforce blue crab population declines
and reduce their resilience to climate change, which will negatively affect fishing industries
and ecosystems across the United States.