From the Bay

The Skinny on Shallow Water: Protected but Vulnerable

Kayaking is such a simple and therapeutic pleasure. Shallow waters abound in the Chesapeake Bay, and car roof racks attest to its popularity. In tidal creeks, rivers and protected bays, passive glides bring nature’s envelopment. Arms work against wind and tide. Immersion and exertion shed worries in the kayak’s wake. ese skinny waters are also therapeutic for the Bay itself. ey are its highestfunctioning habitats: nurseries for sh, beds for reefs and underwater grasses, and incubators for the forage species that sustain oysters, crabs, sh and wildlife.

Little wonder then that these shallow waters receive the government’s highest safeguards. e Chesapeake Bay Program applies its most stringent water quality standards to two classes of habitats: skinny tidal waters, including shoreline waters less than 2 meters deep, and migratory spawning reaches and nurseries, which are mostly shallow, upper estuarine waters where striped bass, perch, shad and other sh reproduce.

Twenty years ago, I worked with a team to develop these protections, and they have stood up well. Still, le in the wake of that e ort are larger perils to skinny waters: climate change, invasive species and development in coastal rural counties.

Along the shores of the Potomac River, we summertime paddlers share skinny waters with countless 2-inch juvenile striped bass. eir numbers vary wildly year-to-year, depending on springtime egg and larval survival. Upriver to Nice Bridge, large females cast billions of eggs to the whims of spring weather. Early mortality is brutal, and bass have adapted by spawning repeatedly over long lifespans. A 30-year-old striped bass has more than 20 times at bat to replace herself.

Enter climate change. Spring is now a less predictable transition between seasons, narrowing the window of favorable conditions. Combined with recent over shing and disease, most females get only one or two times at bat.

Protecting the nursery function of skinny waters against climate change thus has more to do with sheries management — maintaining older spawners — than improvements to water quality.

Enter blue cat sh. From 1974 to 1985, Virginia introduced hundreds of thousands of them into freshwater rivers of the Lower Bay. But the sh had an unexpected predilection for brackish water, and within 20 years they had exploded in abundance, invading all major tributaries.

In a 2013 survey of a 7-mile stretch of the James River, Dr. Mary Fabrizio and her team at the Virginia Institute of Marine Science put the number of blue cat sh at 1.6 million — more than the Bay’s entire commercial harvest of striped bass. As the dominant predator, they’re taking a big bite out of the juveniles that sustain our native sh. ere is no obvious x, but promoting harvests of blue cat sh would help young striped bass and other native sh to evade predation.

Kayaking near Great Mills on the St. Mary’s River requires a good deal of maneuvering between obstacles: submerged snags and overhanging trees and vegetation. is weaving and dodging, great sport in a kayak, is the result of coastal zone protections: Homeowners and small businesses along the river have helped conserve and even enhance shoreline vegetation. ese zones of trees, swamps, marshes and undergrowth provide habitat and bu er skinny waters from runo .

Enter coastal development. Strategic planning for Lexington Park in St. Mary’s County concentrates a corridor of retail, industry and high-density dwellings along MD Route 235 — away from coastal zones.

Yet the county is a narrow peninsula, so the corridor straddles the headwaters of the St. Mary’s River within 1–3 miles of tidal waters. Impervious surfaces exceed 10%, the threshold at which the conveyance of sediment, nutrients and other pollutants harms living resources.

In coastal rural counties and towns, these impervious spines of development continue to grow, paralleling and crossing skinny waters — for instance, along Southern Maryland’s state routes 2, 4 and 5; Virginia’s I-64 and state routes 3 and 17; and the Delmarva Peninsula’s U.S. routes 50 and 13. e stringent EPA protections for skinny waters, though notable in their achievements, have not kept pace with the threats. e most important battle for conserving skinny waters is not in improving agricultural practices in Pennsylvania, nor is it in restoring oxygen to the Bay’s deepest waters. It’s proximate to the skinny waters themselves: actions that give living resources a ghting chance against climate change and other assaults. Essential actions include reversing over shing, reining in blue cat sh and extending coastal zone protections to those spines of coastal rural development.

On a recent paddle in the brackish part of the St. Mary’s River, I reached down from my kayak and plucked a large live oyster from the sandy bottom. e water was crystal-clear except for dense patches of seagrass. ere is much worth savoring and conserving here.

Taste award winning wines at the Port of

Leonardtown Winery. Paddle the McIntosh Run water trail. Enjoy a sunset along Breton

Bay. Dine at an outdoor café. Shop the unique shops and Shepherd’s Old Field

Market. Explore the galleries showcasing Taste award winning wines at local artists in Southern Maryland’s only Arts & Entertainment District. Located in the heart of St. Mary’s County. the Port of Leonardtown Winery. Explore the galleries showcasing local artists in Southern Maryland’s VisitStMarysMD.com/leonardtown only Arts & Entertainment District.

Stay overnight and make it a weekend getaway! Dine on the square at an outdoor cafe. Enjoy a sunset along Breton Bay.

Port of Leonardtown Winery www.POLWinery.com

VisitLeonardtownMD.com

thelba.org

A kayaker pauses in a shallow, narrow passage to capture an image of marsh hibiscus. Photo by Dave Harp

About the Author: Dave Secor is a sheries and environmental scientist at the University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory. e views expressed by opinion columnists are not necessarily those of the Bay Journal. is piece printed with permission. Bayjournal.com