New Study on Climate Change Impact on Bay Finfish

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We hear a lot about how climate change will impact the Chesapeake Bay region, with sea level rise and increased rates of flooding affecting shoreline communities; and ocean acidification potentially harming oyster and blue crab populations. What about finfish species? The U.S. Geological Survery, USGS, has just released a report examining how climate change will affect coldwater fish species (such as the brook trout), native to the Bay watershed. The report relays estimates (through models) on how temperatures of specific streams and watersheds in the Chesapeake Bay region will be impacted with climate change. This new data should allow conservationists to ramp up efforts to protect coldwater fish ecosystems in threatened areas.

Brook trout, and other coldwater finfish species, which can be found in our watershed’s freshwater streams, are expected to suffer from climate change, and warming water temperatures. While previous studies have looked at the relationship between air and surface water temperature to predict future water temperatures of streams, the USGS set out to create more accurate models for climate change impacts on coldwater fish, by taking groundwater into account. Groundwater, especially in headwater streams, can have a major impact on overall stream temperatures. The USGS created models for specific streams throughout the Chesapeake Bay watershed, using groundwater and surface water temperatures, to predict changing water temperatures in the wake of climate change, and with this, the future health of the fish that rely on these streams.

The full report can be found here.

Bay Grass Acreage Up From Last Year

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The abundance of total underwater seagrass in the Chesapeake Bay is up 27% from last year. Underwater grasses increased by thousands of acres across all four water ranges (from freshwater, slightly salty, moderately salty, to very salty) in the Bay watershed. There are currently an estimated 75,000 acres of underwater grasses in the Bay, up from 59,711 acres in 2013. The increase in acreage in each salinity zone (amount of salt in the water) is represented in a table below.

While this increase is a vast improvement from previous years, the Bay needs to have an additional 15,000 acres of underwater seagrass to meet 2017 restoration goals, and a further 40,000 acres to meet 2025 goals, set by the Chesapeake Bay Program (CBP). Beyond 2025, the CBP ultimately aims to restore 185,000 acres of underwater grasses in the Bay. Underwater seagrass acreage is gradually increasing in the Bay, but over 100,000 additional acres must be restored to meet CBP standards.

Zone 2013 Seagrass Acreage 2014 Seagrass Acreage Zone Goal Achievement (%)
Tidal Fresh Salinity 1,320 15,305 74%
Oligohaline Salinity (Slightly Salty) 1,800 7,413 72%
Mesohaline Salinity (Moderately Salty) 11,850 37,260 31%
Polyhaline Salinity (Very Salty) 1,154 15,857 47%

Bay grass acreage can fluctuate from year to year, due to die-offs from heat waves or major storms, such as Tropical Storm Lee in 2011. Long-term threats to underwater grasses, which have resulted in decades of declining seagrass abundance in the Bay, include nutrient and sediment pollution. Nitrogen, phosphorus, and sediment runoff from agricultural activity and urban stormwater runoff contribute to the declining health and die-off of Bay grasses.

Underwater seagrass plays an important role in the Chesapeake Bay ecosystem. Seagrass provides habitat and sanctuary to various underwater species, such as juvenile blue crabs and finfish. Grasses are able to improve water quality by filtering runoff in the Bay and taking up nutrients that would otherwise contribute to pollution in the watershed. Seagrass protects shorelines from erosion by absorbing wave energy and keeping sediment in place.

The 16,000-acre increase in underwater seagrass abundance in the Bay between 2013 and 2014 is great news. This is a trend that I hope to see continue in years to come. However, restoration, at levels expected by 2025, will not be possible without the Bay states’ cooperation in implementing and enforcing regulations that reduce nitrogen and sediment runoff into the watershed. While 2014 numbers are an improvement from previous years, Bay acreage will continue to fluctuate in years to come, and the only way to create a long-term positive trend in future seagrass abundance is to significantly reduce nitrogen and sediment pollution in the Bay.

Figure 1: Survey findings for underwater grasses in Chesapeake Bay in 2014, compared to historical highs and lows. Image source: www.vims.edu/newsandevents/topstories/sav_2014_report.php
Figure 1: Survey findings for underwater grasses in Chesapeake Bay in 2014, compared to historical highs and lows. Image source: http://www.vims.edu/newsandevents/topstories/sav_2014_report.php.

Recent findings on Bay seagrass acreage come from the Virginia Institute of Marine Science (VIMS), which has released their annual report on underwater seagrass abundance in the Chesapeake Bay for 2014, (http://www.vims.edu/newsandevents/topstories/sav_2014_report.php).

For more information on underwater seagrass, please see Part III of our Phosphorus in the Chesapeake paper here: https://beyondthebayblog.com/2015/05/07/phosphorus-in-the-chesapeake-part-iii/.

The Chesapeake Bay’s Blue Catfish Problem

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A growing blue catfish population in the Chesapeake Bay Watershed is depleting the Bay’s native fish population. Regional restaurants, markets and nonprofit organizations are stepping up to this challenge, and offering this invasive species to consumers as a tasty, affordable alternative. Does a higher demand for blue catfish provide a solution to this environmental issue?

The blue catfish is a major predator of the blue crab population in the Chesapeake Bay and its tributaries. The VMRC has named the growing blue catfish population as one of the factors responsible for the low harvest numbers for crabs this year. Originally from the Mid-West, native to the Mississippi, Missouri, and Ohio Rivers, the blue catfish was brought to Virginia in the 1970s and 80s as a sporting fish. Stocked in the York, James, and Rappahannock Rivers, the fish has since spread north, to the Potomac River, infiltrating both Virginia and Maryland waters.

The blue catfish thrives in freshwater, in the Chesapeake Bay’s major Southern tributaries, but can also live in brackish, tidal waters. Since the blue catfish is an invasive species in the Chesapeake Bay Watershed, it has no natural predators in this estuary. An unchecked population can do a great deal of damage to the underwater ecosystem, by preying heavily on shellfish, menhaden, white perch and fish eggs (such as shad), and competing for resources with native fish.

Blue Catfish Range in the Chesapeake Bay. Source: chesapeakebay.noaa.gov/fish-facts/invasive-catfish.
Blue Catfish Range in the Chesapeake Bay. Source: chesapeakebay.noaa.gov/fish-facts/invasive-catfish.

Spawning from late May into June, females of reproductive age release 4,000 to 8,000 eggs per kilogram every year. This can be quite a lot of eggs considering the large size of catfish. The largest catfish caught in Maryland was 84 pounds, while Virginia has recorded the catch of a 140-pound catfish.

While a 2012 Maryland Department of Fisheries report recorded an annual catch of 400,000 pounds of blue catfish, this has not been enough to reduce the environmental damage caused by this invasive species in our watershed. As a response to this issue, many area restaurants and markets have embraced the idea of selling locally caught blue catfish to help reduce the Bay population. Whole Foods and MOM’s Organic Market began to sell this fish in 2014, while restaurants such as Clyde’s, and other popular D.C. restaurants, now offer catfish on their menu.

A regional nonprofit, Wide Net Project, has also found a way to address this environmental issue, and works to build up the market for blue catfish. Wide Net Project works with regional markets, restaurants, and food service companies, marketing the blue catfish as a local, sustainable, tasty and inexpensive food item. In addition, this nonprofit works to stock local hunger relief organizations with the fish. A quarter pound of blue catfish is donated for every pound sold. In 2015, Wide Net Project is expecting to sell 75,000 pounds and donate tens of thousands of pounds of blue catfish.

Cleaning Up Bay Tributaries

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Interesting article in today’s Washington Post about a husband-and-wife led scientific team in Maryland experimenting with ways to clean up the tributaries of the Chesapeake Bay.

How much is a polluted Chesapeake Bay costing us?

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What are the benefits to cleaning up the Chesapeake Bay? I usually focus on the biological and ecological benefits to watershed cleanup, but the Chesapeake Bay Foundation has been looking at economic benefits. They released a report earlier this month estimating that cleaning up the Bay could result in earnings of $130 billion dollars each year for states in the watershed. On the other hand, failing to enforce pollution diets or follow the 2010 Clean Water Blueprint, will result in billions of lost dollars in the region.

The report estimates the economic benefits from watershed cleanup and regulation will improve recreational opportunities; support local businesses, restaurants and watermen; and reduce risks associated with flooding, air pollution and climate instability. The report looks at the savings possible for each state involved, and for the overall watershed.

In the News

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There have been a variety of stories in the news lately on the Chesapeake Bay watershed. I’ve picked out some of the ones I’ve been reading to share:

From Delaware Online: The Federal Energy Regulatory Commission approved the export of liquefied natural gas from Dominion Energy’s Cove Point facility on the Bay. Natural gas will likely begin to be exported from this location starting in 2017, and be carried via ships to Japan and India. Many environmentalists remain opposed to this plan, citing concerns over the extraction, processing and shipping of natural gas.

From CBS Baltimore: Baltimore County has allocated $13 million to clean up White Marsh Run, a tributary of the Chesapeake Bay. Flooding and erosion result in frequent bursting of sewage pipes, sending sediment and waste downstream into the Bay. The funds will allow for construction crews to rebuild the stream and relocate the sewage pipes.

From the Washington Post: Journalist Darryl Fears highlights the recent return of sturgeon, decline of rockfish, and the rise of the invasive water chestnut grass to the Bay and its tributaries.

Grant Funds Awarded to Chesapeake Bay Restoration Projects

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The National Wildlife Foundation’s Chesapeake Bay Stewardship Fund has awarded $9.8 million to various environmental projects in the Bay watershed. These projects aim to reduce pollution, improve water quality, and restore wetlands and forest buffers. Individual projects include the installation of rain gardens in the District, and storm water management programs in Virginia.

(Chesapeake Bay News; Chesapeake Bay Stewardship Fund)

Osprey Used as Indicators for Environmental Hazards

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Spend a day on the Chesapeake Bay and you’ll see osprey all around- nesting on channel markers, diving for fish in the water, and flying above your head. These birds are common to the Chesapeake Bay, and live near bodies of water across the globe. Some 40 years ago, a sighting of an osprey in the Bay would have been much rarer.

Osprey were endangered in North America throughout the 1940s, 50s and 60s with the widespread use of DDT as a pesticide. By 1975, species numbers had fallen by 90% on our continent. DDT was the cause for this decline, as it harmfully impacted osprey eggs; the birds were laying eggs that were not hatching, or had shells so thin that they broke during incubation. The use of DDT for agricultural purposes was eventually banned in 1972, and since the phaseout of DDT, osprey have had an incredibly successful comeback in North America.

Although DDT is no longer a threat to osprey, there are a number of other chemicals and contaminants that humans use and dispose of that make their way into the osprey’s food chain. I read an article from Environmental Health News that discusses some of the other threats facing osprey today. The article, “Osprey whisperers: Deciphering decades of clues from the sea hawk,” talks about how osprey respond to contaminants they ingest. The author uses several examples of the effect of contaminants on osprey in different regions, including the discharge of prescription drugs into the Chesapeake Bay. Osprey, which eat fish, are at the top of their food chain. Pollutants found in the waters where osprey live bioaccumulate in the food chain, and can have serious impacts on these bird’s reproductive and migratory habits. The article points out that examining how osprey are affected by what they eat can be indicators for their health as well as human health. Often, what is damaging to these birds, can be damaging to humans, if ingested or exposed to certain chemicals at high enough levels.

I encourage you to take a look at this article, which I’ve linked to above. I found this particular piece through a post on the New York Times Dot Earth blog, where the author looks at the many ways birds can warn us about the health of our surrounding environment (“Winged Warning: Heavy Metal Song Distortion“).

Update on Blue Crab Regulations

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Late last month the Virginia Marine Resources Commission (VMRC) published a press release on new crabbing regulations the agency had issued to reduce the harvesting of female and juvenile crabs in Virginia waters. The VMRC voted to reduce the female blue crab harvest in Virginia by 10% over the next year, effective July 4, 2014 through July 5, 2015. New limitations on blue crab culling reduce bushel limits by license category (number of crab pots a certain crabber has a license for).The VMRC has also closed winter dredging of blue crabs for this upcoming winter, for the seventh year in a row.

This spring I posted on the incredibly low numbers of blue crabs in the Chesapeake Bay and spoke to the VMRC on steps moving forward. (“Blue Crab Numbers Low Again This Year,” “Information on Blue Crab Regulations“). As stated, the VMRC consulted with two partner agencies, the Maryland Department of Natural Resources and the Potomac River Fisheries Commission, and used two advisory committees (the Crab Management Advisory Committee and the Crab Industry Advisory Committee) to make their decisions.

According to the VMRC, the new regulations will protect juvenile crabs and and will “[bolster] the number of spawning age females.” Reducing the catch of these crabs will help to bring the overall crab population back to a sustainable level in the coming seasons.


The Health of the Bay

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The Health of the Bay

The University of Maryland Center for Environmental Science released their annual health report and score for the Chesapeake Bay. The report focuses on 2013, and awards the Chesapeake a C, the same score as last year. Although the lower Bay has seen some progress, the estuary overall needs more help. The primary limiting factor for stream health again seems to be nutrient and sediment pollution from stormwater runoff.