Chesapeake Bay Activities Newsletter October-December 2022

A case study of temporal trends in risk factors associated with endocrine disruption in smallmouth bass

Issue

The USGS has a long-term research effort that identified endocrine disruption in smallmouth bass (SMB) in the Chesapeake Bay watershed.  Endocrine disruption can cause many changes in fish, including intersex characteristics where fish develop characteristics of the other sex, such as immature eggs forming in males. An overview by USGS of endocrine disruption in fish found the condition downstream of wastewater treatment plants and in watersheds dominated by agricultural land use; however, no single cause or environmental stressor has been directly identified (Blazer and others, 2021).  To better understand the risk factors associated with SMB endocrine disruption, the USGS conducted monitoring and analysis at a site in the Potomac River Basin to assess effects of agricultural land use.  The results from these research efforts are informing several outcomes of the Chesapeake Watershed Agreement, including a better understanding of the occurrence and effects of contaminants, improving water quality, and restoring fish habitat. 

Agricultural best management practices can improve water quality and conditions for fisheries in the Chesapeake Bay Watershed

Issue

Partners in the Chesapeake Bay Program (CBP) are implementing best management practices (BMPs) to prevent nutrient and sediment from entering waterways across the Chesapeake watershed and reduce loads to the Bay. In addition to reducing nutrients, CBP partners want to better understand how BMPs can provide additional benefits for addressing toxic contaminants, such as pesticides, hormones, and pathogens. Agricultural land use and activities (manure application, pesticides use, phytoestrogens in crops) are known to contribute compounds to surface waters that disrupt normal hormone function in organisms. High levels of estrogenic activity have been observed to adversely affect fish and are linked to effects including intersex in male fish, increased susceptibility to immunosuppression and parasites or lesions, and potential population-level effects. An effects-based threshold of 1.0 ng/L has been used to categorize low and high levels of estrogenic activity in relation to fish health. 

USGS and CBP produce report to enhance Chesapeake Bay and watershed monitoring networks

Issue: In March 2021, the Principals’ Staff Committee (PSC) requested a study and recommendations on how to enhance the Chesapeake Bay Program (CBP) monitoring networks to improve decision-making for the goals of the Chesapeake Watershed Agreement.  The monitoring networks include (1) CBP core networks supported primarily by EPA CBP funding (i.e., Tidal Water Quality, Nontidal Water Quality, Submerged Aquatic Vegetation, Tidal benthic macroinvertebrates, Community Science, and Land Use Land Cover), and (2) partnership networks supported by multiple federal and state agencies. 
 

Enhanced understanding of factors affecting stream condition can improve restoration outcomes

Issue: The Chesapeake Bay Watershed Agreement has an outcome to improve stream health. Current restoration approaches have led to mixed improvements in stream conditions, indicating that some major stressors and their sources were likely overlooked. Managers could benefit from synthesized information on most reported stressors responsible for aquatic community impairment and their linkages to other stressors to improve restoration approaches.

USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses are important because they put oxygen into tidal waters, provide habitat for fish and crabs, and food for waterfowl.