A small crayfish is found along the banks of the Potomac River in Shepherdstown, West Virginia. The thousands of rivers and streams that flow to the Chesapeake Bay are home to many species of native crayfish—also called crawfish, crawdads or mudbugs—which are freshwater crustaceans that resemble small lobsters. But several species of invasive crayfish also call the waterways home, displacing native species of crayfish and reducing the amount and diversity of underwater plants.
Certain species of crayfish are commonly eaten or even kept as pets in freshwater aquariums. But the widespread use of live crayfish by fishermen as bait has led to their introduction in waterways across the region. Unused buckets of live crayfish are often unknowingly dumped into rivers and streams, where they aggressively establish themselves at the expense of native crayfish populations.
Some of the most infamous invasive crayfish in the region include the rusty crayfish (Orconectes rusticus), the red swamp crawfish (Procambarus clarkii) and the virile crayfish (Orconectes virilis). According to the Maryland Department of Natural Resources (DNR), virile crayfish populations in the state are nine times more abundant than all native crayfish species combined. And because removing invasive crayfish would harm other, native species, prevention is the only effective way to stop the spread. The DNR recommends never moving caught crayfish from one waterbody to another and either disposing of unused bait humanely or saving it for future use.
Learn more about invasive species in the Chesapeake Bay watershed.
Image by Will Parson
Not all the animals who live in and along the Chesapeake Bay and its tributaries are as cute as a playful river otter or as majestic as a soaring bald eagle. Whether hidden in cracks and crevices or buried deep in the mud, a multitude of scuttling, slithering and swarming critters call the Bay home. Celebrate the spookiest time of the year by learning about a few of these creepy-crawlies.
Common Spider Crab
Covered in spines and coated in algae, this slow-moving crustacean probably wouldn’t win any beauty contests. Also known as the portly spider crab or the nine-spined spider crab, the common spider crab belongs to a group known as “decorator crabs”: several species of crabs that use materials from their environment to hide from predators. For the common spider crab, this includes attaching algae, debris and small invertebrates to the hook-like hairs that cover its spiny shell.
Spider crabs eat mostly detritus—bits of dead plants and animals—which helps keep the ecosystem free of rotting materials. Their eyesight is poor, but they use the sensitive tips of their legs to identify food in the water or mud as they walk.
Slender, stick-like and mostly transparent, the alien-looking skeleton shrimp is an underwater resident of the mid- to lower-Bay. These tiny, gangly amphipods—a type of small crustacean—use their hooked, grasping rear legs to latch on to hydras, sponges and vegetation, leaving their folded front legs free to capture algae, plankton and detritus. Some species of skeleton shrimp can even change color to blend in with their surroundings.
Crawling, burrowing and covered in tiny appendages, bristle worms can be found along the shorelines, mudflats and shallow waters of the Bay and its rivers. More than 110 species of bristle worms—also known as polychaetes, which translates to “many hairs”—have been recorded in the Chesapeake Bay region, including the common clam worm and the creatively-named ice cream cone worm.
Some species of polychaetes crawl freely throughout the shoreline and shallow waters, while others prefer to tunnel deep into the mud, seldom leaving their tube-like burrows. By feeding on plankton, algae and detritus, and being eaten by fish and birds in turn, bristle worms play a key role in the Bay’s food web.
Although named for their similarity to common cockroaches, sea roaches or wharf roaches are not insects. They’re actually small isopods—a type of crustacean that often has a rigid, segmented outer shell instead of a skeleton. While sea roaches live mostly above water, they breathe through gills that must stay wet in order to work properly. This means these critters are most often found scurrying close to the water line—on rocks, piers and jetties—scavenging for decaying bits of plant and animal matter.
Experts aren’t sure where sea roaches are originally from, but the first record of one of these critters in the Chesapeake Bay region occurred in the early 1900s. While not a native species, scientists haven’t found a significant negative impact from sea roaches on the native species of the area.
The “devil” in this crayfish’s common name could refer to several of its characteristics: the red highlights that appear around its eyes and claws, its habit of spending most of its life in underground chambers or the painful pinch its claws can deliver. Resembling a miniature lobster, the devil crayfish is found primarily in freshwater rivers and streams, where it burrows deep underground and seldom emerges. Burrows can be recognized by their cone-shaped “mud chimney” entryways, formed by mud the crayfish carries from the burrow and places by the entrance.
Want to learn about more creepy-crawlies that live in the Bay? Check out our field guide!
More than 145,000 lost or abandoned crab traps may be resting on the bottom of the Chesapeake Bay, according to a recent report from the National Oceanic and Atmospheric Administration’s (NOAA) Marine Debris Program. Once lost, these so-called “ghost pots” can continue to catch crabs, fish and other species, resulting in the loss of an estimated 3.3 million blue crabs each year. Though this makes up a small proportion of the total number of blue crabs in the Bay—estimated at 553 million in 2016—the study suggests that the targeted removal of derelict fishing gear could help boost commercial crab harvest.
Each year, an estimated 600,000 crab pots are actively fished by watermen on the Bay. But whether accidentally lost or intentionally tossed overboard, 12 to 20 percent of these traps are lost each year. Lines connecting traps to buoys can come loose or be cut, strong storms can relocate the gear or pots may simply be abandoned.
This lost fishing gear can continue to “ghost fish,” trapping crabs, finfish and other underwater animals. According to the study, more than 6 million blue crabs are caught—and 3.3 million of those killed—by ghost pots each year. More than 3.5 million white perch and close to 3.6 million Atlantic croaker are also estimated to be trapped each year. And derelict gear can harm sensitive habitats like underwater grass beds and salt marshes as well.
In addition to the environmental impacts of derelict crab pots, the team of researchers—which included experts from the Virginia Institute of Marine Science—looked at how abandoned fishing gear could affect commercial crab harvest. By catching crabs that could otherwise be caught by actively-fished traps, ghost pots can potentially result in a loss of harvest. The study estimates that the removal of derelict pots from 2008 to 2014 resulted in an increased Bay-wide blue crab harvest of more than 38 million pounds—valued at $33.5 million—over the six-year period.
Removing derelict pots from heavily-fished areas could be a cost-effective way to boost harvest and reduce the gear’s harmful ecological effects, the study suggests. Biodegradable escape panels, which are inexpensive and easy to install, are another option that have been successfully tested in the Bay.
The report, Ecological and Economic Effects of Derelict Fishing Gear in the Chesapeake Bay, can be found online.
Robin Dunbar of the Elizabeth River Project conducts a teachers' workshop at Paradise Creek Nature Park in Portsmouth, Virginia. The area surrounding Paradise Creek—a tributary of the Elizabeth River—was once nicknamed "Paradise Lost" because of its close proximity to the former New Gosport landfill. Now, the creek has become a model for urban waterway restoration.
Since 1991, the Elizabeth River Project has worked tirelessly to restore the Elizabeth River, which flows between the cities of Norfolk, Portsmouth and Chesapeake, Virginia, before making its way to the Bay. For years, the river was one of the most polluted in the region. But in recent years, though the river still faces a long road to recovery, improving trends have brought new hope to a waterway once thought to be devoid of life.
In addition to on-the-ground restoration projects, part of the Elizabeth River Project’s mission is connecting with and educating the local community. Initiatives include the River Star Homes, River Star Schools and River Star Businesses programs; the Learning Barge, a 120-by-32 foot barge-turned-classroom; and Paradise Creek Nature Park, which hosts educational programs for both schools and the general public.
Learn more about the Elizabeth River Project.
Image by Will Parson