Two sandfleas below the coquina clams show typical size range of these unusual burrowing crabs. Their presence, like that of the clams, indicates a healthy beach—and good fishing! (FWC photo)
March 31, 2024
By Steve Wayne
Every surf angler knows the value of good bait and sandfleas are like gold. In years past, a little digging along the surf line on most any Florida beach revealed the presence of mole crabs, a.k.a. “sandfleas.” Fast forward to the present time, where did all the sandfleas go? On many Florida beaches, they are nonexistent.
Jerry Pope, a commercial sandflea harvester from East Central Florida, has seen a noticeable decline in sandflea abundance. Several years ago, the populations were so good that Pope and his business partner Jim Balazs could easily fill an order for 40 gallons of sandfleas in just an hour. “They were large sandfleas and we called them ‘turtles’ or ‘bucket fillers’ because they were so big,” boasts Pope. After three years of back-to-back storms, he noticed a change. “Once the trucks moved into the zone where the sandfleas were and began beach renourishment, the sandfleas were pushed farther down the beach,” explained Pope. “Eventually the whole beach was covered up with new sand and it was over.” The sandfleas were gone. Pope is going on his third year of harvesting a very minimal amount of sandfleas.
Pope and Balazs also noticed a shift in the small number of sandfleas remaining on beaches. The sandfleas went from coming up the beach shallower in the day to changing their habits and coming up the beach shallower at night. They also noticed that the crabs moved out to the safety of non-renourishment areas in a deeper zone in the water away from new sand. Pope feels that as sandfleas disappeared, they could easily be pushed offshore. As commercial harvesters on land, they would never know if sandfleas moved into deep water.
Good bait, and good subject for further scientific study. (FWC photo) The decline of sandfleas is not limited to the east central Florida coast. Other beaches in Florida have also shown a decline. A check of the Florida Fish and Wildlife Conservation Commission (FWC) trip ticket data for commercial mole crab harvesters revealed that 32,651 pounds of sandfleas were harvested statewide during 2020. That number has gone down to a mere 7,652 pounds of total harvest for the entire state of Florida during 2022, a 77 percent decline in just two years. Because mole crabs have become so hard to find, commercial harvest trips are down considerably in Florida. A total number of 330 trips for commercial mole crab harvesters in Florida were recorded in 2020. In a span of just two years, only 116 trips were made by commercial harvesters in 2022. Recreational anglers are also feeling the pinch; many say sandfleas are nearly impossible to find.
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Beach Renourishments
Historically, large volume beach renourishment projects—the efforts beachfront communities undertake to rebuild eroding shores—primarily used sand from offshore sources. Smaller volume beach renourishment projects and post-storm recovery efforts have occasionally used sand (dirt) from upland sand mines, which some people feel may have deleterious impacts on crabs and other marine species.
With over 825 miles of beaches, the state of Florida routinely spends $90 million on beach renourishment efforts. The Florida Department of Environmental Protection (DEP) Beaches program overseas beach restoration efforts, as the state legislature views beach restoration as a statewide issue that is not just confined to local beaches in local governmental jurisdictions. Funds are cost shared with local governments and have contributed to the restoration and subsequent maintenance of more than 253 miles, or 60 percent, of the state’s 422 miles of critically eroded beaches. Because the DEP overseas restoration, one might assume an emphasis on environmental awareness, given the more than 30 plant and animal species considered rare living in and among the sandy coastlines.
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Other Possible Causes
Florida Fish and Wildlife Research Institute biologists have very little data as they do not routinely monitor mole crab population changes. State biologists do feel that the impact from natural storms may have the largest short-term impact on mole crab movements, as beach renourishment tends to move at a slower rate, giving crabs time to move down the beach or deeper in the water away from new renourishment sand. Other causes for short-term movements may be red tide or an increase in freshwater discharges, which routinely plague both coasts. Both recreational and commercial harvesters collect sandfleas above the waterline, so little is known if the crabs move out deeper into the water (or where they actually move to).
Fish and Wildlife Commission biologists feel that there are many things that could be affecting long-term mole crab abundance. “Florida is ever so slightly getting warmer each year, and we are at the edge of the temperate and tropical regions, so many species here are getting pushed north by water temps,” advises FWC Research Scientist Stephen Geiger. Geiger also thinks that rising sea levels may be pushing more and more beaches up against seawalls, contributing to extra nutrients leaching into the water.
Geiger feels that as Florida’s population rapidly expands, the waste reclamation systems are strained, which leads to failing septic systems along both coasts. As a result, pharmaceuticals are now easily detectable in many waters here in Florida, as they are not removed by either septic or sewer plants. Water quality is altered which may contribute to mole crab movements. Commercial harvester Jerry Pope agrees. “I think that there’s a combination of us trying to protect our beaches and oceanfront property and there’s a lot more people,” he said. “We have not upgraded our sewer systems.”
Unfortunately, there is little known as to if, when, and how mole crab populations change in Florida. There are not any long-term studies completed (yet) in Florida to provide any indication of any problems associated with mole crab populations. The FWC faces limited funding for research and many different governmental, environmental, and tourism organizations all weigh in on the health of our beaches. Sadly, many different creatures including sandfleas may become victims both from a variety of our decisions and from environmental factors.
This article was featured in the March issue of Florida Sportsman magazine. Click to subscribe .
