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
When you imagine fish in the Chesapeake Bay, top predators probably come to mind. But the most important fish in the Bay weighs no more than a pair of playing cards, measures no longer than the width of your hand and is more abundant than any other fish that calls the Chesapeake home.
The bay anchovy (Anchoa mitchilli) can be found in great numbers along the Atlantic coast and in all parts of the Chesapeake Bay. “It is the single most abundant fish on the east coast of North America," said fisheries scientist Ed Houde. “That in itself says something about its importance.”
Because it is such an oft-consumed prey item for so many predators, the bay anchovy is considered a forage fish. But the bay anchovy stands out among forage species. Scientists have long known, for instance, that the bay anchovy is a major source of energy fueling the growth and production of predators in the Chesapeake, and can even comprise up to 90 percent of the diets of predatory fish in the fall. A recent investigation into the diets of five predatory fish found that the bay anchovy was the fishes’ most common prey, confirming the bay anchovy is the most important forage species in the Bay ecosystem.
“We’ve studied the production and consumption of bay anchovy in the Chesapeake Bay, and the numbers are impressive,” said Houde, who worked at the University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory for more than 35 years and served as the institution’s Vice President for Education before retiring in July 2016. According to Houde, about 50,000 tons of bay anchovy can be found in this estuary at any given time—but an average of 458,000 tons are produced here each year. “That means a huge amount is being eaten and is fueling the production of Bay predators,” Houde said.
According to Houde, several characteristics make the bay anchovy the perfect prey fish. First, it’s a small fish, which means a range of predators both big and small can fit the fish into their mouths. Second, it’s a fecund fish, which means it spawns large numbers of eggs; eggs, larvae, juveniles and adults are eaten by predators. Third, there are a lot of them, almost everywhere, all the time. While other prey species may only inhabit certain areas of the Bay at certain times of year, the bay anchovy is generally available throughout the Bay most of the year.
Indeed, the bay anchovy is surprisingly tolerant of both the normal fluctuations observed in an estuarine environment and the hostile conditions that can occur when this environment is stressed. Through laboratory experiments and field work, Houde and his students have found that low dissolved oxygen, for instance, may not impact the bay anchovy like it impacts many other species. Areas of low dissolved oxygen—which occur in the Bay each summer, and which can suffocate shellfish and other organisms living on or near the bottom—seem to affect the distribution of bay anchovy but not their death rates, driving adults into the lower portion of the Bay. Coincidentally, it is in this portion of the Chesapeake that bay anchovy larvae and young are most likely to thrive. It may seem counterintuitive, but in this way, low dissolved oxygen can enhance the bay anchovy’s reproductive success.
“This is not an argument to support benefits of low dissolved oxygen in the Bay,” Houde cautioned. “But in the case of the anchovy, it does seem to promote conditions that increase its productivity.”
The Maryland Department of Natural Resources and Virginia Institute of Marine Science have gathered survey data on bay anchovy abundance for decades, and the University of Maryland Center for Environmental Science has also tracked this number as an indicator of Bay health. While bay anchovy populations fluctuate seasonally and annually and the fish is less abundant now than in the decades before 1990, Houde does not believe the bay anchovy has declined since the mid-1990s.
That said, Houde acknowledges that there must be environmental thresholds the bay anchovy cannot successfully cross. Little research has been done into the effects that chemical contaminants could have on the fish, and environmental conditions that lower plankton productivity—the mainstay of the bay anchovy’s diet—could have substantial effects on anchovy production and abundance.
How can we ensure the continued abundance of the most important fish in the Bay? “Ensuring the bay anchovy population remains healthy depends on keeping estuaries healthy,” Houde said. “Good water quality that supports abundant zooplankton to fuel anchovy production is what we need to maintain the health of anchovies. That’s not so different from [protecting] most of the things in the Bay.”
Through the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program has committed to improving our understanding of the role of forage species in the Bay. Learn about our work to develop a strategy for assessing the Bay’s forage base.