The science

Mole crabs (sand fleas) and coquina clams

• On North Carolina beaches, mole crabs and coquinas were 86–99% lower on nourished beaches 5–10 weeks after nourishment compared with control beaches (Peterson et al. 2000, Journal of Coastal Research 16(2)).
• On Topsail Island, NC, mole crabs virtually disappeared for a full year after one nourishment event, and coquinas dropped more than 50% (Peterson et al., monitoring review; Marine Ecology Progress Series, doi:10.3354/meps10870).
• Florida's mole crab (Emerita talpoida) lives in the swash zone and filters plankton and detritus from the waves (FWC species profile).

Ghost crabs

• Bulldozing to build dunes cut active ghost crab burrows by 55–65% about three months later (Peterson et al. 2000).
• At Pea Island National Wildlife Refuge, NC, ghost crabs were less abundant than at control sites after nourishment, then returned to parity by 2016–2017 (Heliyon 2023).

Recovery times

The studies above show recovery ranging from months to about two years depending on the species, the sand used and the timing. The NC review found mismatched (finer or shellier) fill drove the worst damage and slowed recovery (Peterson et al.). Florida-specific pre/post counts of mole crabs on nourished beaches are, as far as we have found, not published, and that is the gap our monitoring program plans to fill.

What permits monitor today

Required monitoring under the U.S. Fish & Wildlife Service's 2015 statewide sand placement biological opinion centers on sea turtles, beach mice and shorebirds, with conditions like compaction testing and tilling (USFWS 2015 SPBO). We found no routine requirement to count mole crabs or coquinas.