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  Archived Posts From: 2016


WMAP, This is How We Roll…

Written on: December 9th, 2016 in Outreach

We (the Wetland Monitoring & Assessment Program, aka WMAP) learn and grow every year.  Looking back at 2016, we decided to share our top four fun items that we learned or experienced along the way, and a field notebook page infographic pointing out some of our accomplishments throughout 2016.  Enjoy!

Lessons Learned This Year:

This aerial view shows all the muskrat homes (brown dots) on a small portion of the Appoquinimink watershed.

This aerial view shows all the muskrat homes (brown dots) on a small portion of the Appoquinimink watershed.

  1. You never know what you might find in a wetland.  You might find a cool terrarium or a ginormous lamp pole shade.  Check out the Trash or Treasure’s blog post.
  2. When looking at aerial photographs, muskrat homes in the marsh make the land look like it has chicken pox.
  3. Always check the tidal range of a site.  If you don’t, you and your boat might end up high & dry. Womp womp..
  4. Our seasonal people actually like what they do over the summer in spite of working in 100°F weather and really hummocky sites.  Check out Confessions of a Seasonal Part 1 & Part 2.

2016 Accomplishments:


Fiddler Crabs: From Burrows to Zoea

Written on: December 9th, 2016 in Wetland Animals

Guest Writer: Kari St.Laurent, Delaware National Estuarine Research Reserve

Fiddler crabs and their burrows at the St. Jones Reserve in Dover. Credit: Kari St.Laurent

Fiddler crabs and their burrows at the St. Jones Reserve in Dover. Credit: Kari St.Laurent

Fiddler crabs are one of the most iconic critters in the salt marsh. Male fiddler crabs have an unmistakable single large claw, paired with a tiny claw, which is used to court female fiddler crabs. But did you know that crabs start their life as microscopic zooplankton? Fiddler crabs undergo multiple molts to grow from a tiny, drifting zooplankton to the rock-sized crabs we see scurrying around the marsh each summer.

Fiddler crabs create complex burrows within the marsh that serve as their homes, which can make the brown marsh mud look like Swiss cheese. Research has suggested that fiddler crab burrows help to move oxygen from the atmosphere to the roots of marsh cordgrasses like Spartina alterniflora.  However, too many fiddler crab burrows can stop cordgrass root mats from forming and potentially hinder plant growth.

Thus, a change in fiddler crab populations can affect salt marshes in different ways, making it a fine balance with a lot of unknowns.

Magnified view of a zoea, or larval crab, from the St. Jones River. Credit: Kari St.Laurent

Magnified view of a zoea, or larval crab, from the St. Jones River. Credit: Kari St.Laurent

In the upcoming months, researchers, students, and volunteers working at the Delaware National Estuarine Research Reserve will be monitoring zooplankton diversity at the St. Jones Reserve in Dover. One of the most common types of zooplankton found in the brackish sections of the St.Jones River are zoea, or larval crabs! This monitoring effort will help us better understand which species of zooplankton are present and how that diversity changes on both short and long timescales.

Additionally, in the upcoming summer, researchers from the National Estuarine Research Reserve System are hoping to conduct a study to look at crab burrow densities within different marshes across the country.

Connecting the fiddler crab burrows we see in the ground with the microscopic baby crabs swimming in the water, will help us understand if fiddler crab populations are changing, and if that change has an effect on our salt marshes, for better or for worse.

Stay tuned for volunteer opportunities and educational programs!

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Saltmarsh Scientists

Written on: December 9th, 2016 in Outreach

Eco-Explorers walk along the tidal stream and Shoveler Pond at the Aquatic Education Resource Center

Eco-Explorers walk along the tidal stream and Shoveler Pond at the Aquatic Resource Education Center (ARE). Credit: ARE

Guest Writers: Mary Rivera and Debra Forest, Division of Fish and Wildlife, Aquatic Resources Education Center

The quiet of a peaceful morning in the Woodland Beach saltmarsh is interrupted by a flock of 60 lively fifth grade students. Squeals of delight emanate from several of the children at the fish station where they get a close-up look at native fish. Many of the students have never touched or held a fish before. Their nervous giggles are replaced by wide grins when they hold a mummichog or bluegill and learn about fish characteristics and adaptations.

Students measure salinity using a hydrometer. Credit: ARE

Students measure salinity using a hydrometer. Credit: ARE

At the macroinvertebrate station, several budding fifth grade scientists dip net in a freshwater pond, collecting specimens to identify and study. On the boardwalk, a group of students conduct water quality tests on a bucket of brackish water. The kids take turns measuring DO, salinity and pH, using an array of testing equipment. Another group moves along the boardwalk on a scavenger hunt for typical plants that grow in this unique ecosystem. Ten more students sit on benches in one corner of the boardwalk, listening intently to the natural sounds of the marsh.

The students in each of these groups are participating in an Eco-Explorers field trip at the Aquatic Resources Education Center.

The Eco-Explorers Program is designed to complement the science curriculum for fifth grade classes in Delaware. Participating teachers receive training and materials they will use in the classroom to introduce their students to the topic of wetlands. After completing the classroom segment of the program, teachers bring their classes to the Aquatic Resources Education Center near Smyrna to spend a day outdoors being “scientists”.

Parent volunteers accompany the school groups to chaperone the students and help them as they explore the saltmarsh. Often the parents are as thrilled and engaged as their children as they discover this wonderful and valuable locale.

These Eco-Explorers found a good spot to observe fiddler crabs and animal tracks. Credit: ARE

These Eco-Explorers found a good spot to observe fiddler crabs and animal tracks. Credit: ARE

Students have the opportunity to investigate six different eco-stations in the marsh where they learn about fish, macroinvertebrates, plants, and water quality. They also learn to observe and interpret signs of animals that live in the salt marsh. They explore the ARE’s boardwalk and ponds to discover the relationship of the marsh to Delaware Bay. The guided field work reinforces classroom learning and allows the students to observe first-hand the living and non-living components of the saltmarsh ecosystem.

Eco-Explorers activities are hands on and students are encouraged to try tasks that real scientists would perform when studying an ecosystem. Activities are led by a talented and knowledgeable staff of seasonal employees and volunteers. Field trips are offered every spring and fall and available dates fill up quickly with teachers eager to explore the marsh with their students.

Over the years, tens of thousands of students, parent chaperones and teachers have had the opportunity to participate in the Eco-Explorers Program and take away a deepening respect for the value and importance of Delaware’s wetlands.

The boardwalk at the Aquatic Resources Education Center is open to the public whenever there are no scheduled programs. Visitors to the Center will find this hidden gem situated along Route 9 near Smyrna. They can stroll along the boardwalk, enjoying beautiful marsh vistas and glimpses of the abundant birds and wildlife that inhabit the marsh. Two stocked, catch and release fishing ponds are also available for public use.

A new Aquatic Resources Education Center is scheduled to open very soon in partnership with Delaware’s Bayshore initiative. The new facility will provide additional indoor and outdoor interpretive areas plus new hiking trails.

For more information about the Eco-Explorers Program and the Aquatic Resources Education Center, go to

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Wetlands & State of the Bays Report

Written on: December 9th, 2016 in Wetland Assessments


Cover of the 2016 State of the Delaware Inland Bays Report.

Guest Writer: Katie Georger, Delaware Center for the Inland Bays

In November, the Delaware Center for the Inland Bays (CIB) released the 2016 State of the Bays report, a 70-page compilation of environmental data about the Rehoboth, Indian River and Little Assawoman Bays and their watershed.

In assembling this report, we considered thirty-five environmental indicators to determine the health of our watershed. As you may have guessed, one of these indicators is salt marsh acreage and condition.

So what did we find? Our salt marshes are slowly disappearing – and with more than one culprit responsible.


Urbanization & Development
Perhaps the most well-known cause of wetland loss is urbanization and development.

Between 1938 and 1968, about 22% of the Inland Bays’ salt marshes were lost to excavation and filling for development. Luckily, this trend has slowed due to Delaware’s 1973 Wetlands Act which legally protected salt marshes.


Click image to view a larger version.

Still, in the last five years, developed areas in the watershed increased by 7.8 square miles (11%), replacing agricultural lands, upland forests, and wetlands. And with the population of the watershed projected to increase in the coming decades, the demand for land is sure to continue.

Currently, most direct destruction of salt marsh in the Inland Bays watershed has been halted. That means that the recent cause of marsh loss is a different beast altogether.

The Drowning Marshes
Since 1992, there has been a noticeable increase in the amount of open water in the interior of our salt marshes. While such open water pools are not completely uncommon, the amount of water trapped in them is excessive. Our marshes are slowly drowning.

Marsh pooling and mosquito ditches in Delaware's Inland Bays.

Marsh pooling and mosquito ditches in Delaware’s Inland Bays. Credit: CIB

There are actually thought to be two causes for this phenomenon: sea level rise and old ditches.

As you would expect, sea level rise is slowly causing the marshes to be underwater more frequently and for longer periods of time, as higher tides flow in and out of the Indian River Inlet.

The old mosquito control ditches are contributing to this drowning. These ditches were intended to control mosquito populations by allowing water and fish into an otherwise marshy area, where they can feed on mosquito larvae. Now too much water is getting into in the interior marsh, where it becomes trapped.

Between these ditches letting too much water into the marsh, and sea level rise creeping up higher, these important habitats are slowly becoming lost in the waters by which they once thrived.

Wetland Loss Affects Us All
The total acreage of salt marshes fringing the Bays was 7,300 when last inventoried in 2007- a net loss of over 3,500 acres since 1938.

Black-crowned Night Heron in marsh.

Black-crowned Night Heron in marsh. Credit: CIB

This means that we are losing protection from flooding and erosion, our natural filter for pollutants, and important carbon storage. But the loss of marshes is also harmful to water quality, as well as living resources in the Bays.

Degradation of salt marshes means loss of critical habitat for native critters including diamondback terrapins, blue crabs, mussels, oystercatchers, laughing gulls, terns, egrets, blue herons and more.

Looking Ahead

Activities to protect natural habitats in the Inland Bays watershed have nearly stalled since the previous State of the Bays report was published in 2011. Our wetlands are disappearing. As we look to the future, it is obvious that funding and incentives for conservation, enhancement of forested buffers, and wetlands protection are gravely needed.

Terrapin in hand.

Terrapin in hand. Credit: CIB

What can we do?

  1. Enhance the existing Sussex County water quality buffer ordinance to provide for wider natural buffers between marshes and developed lands.
  2. Consider state regulation that provides greater protection to freshwater wetlands similar to those regulations of neighboring states.

To read the 2016 State of the Delaware Inland Bays Report, visit

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