18 
water clarity criteria (NOAA Fisheries 2004). The endangered green sea turtle feeds 
directly on sea grasses while other sea turtle species feed on shellfish which are 
dependent on the underwater grasses for habitat. The criteria for water clarity fully 
support the survival, growth and propagation of balanced, indigenous populations of 
ecologically important fish and shellfish inhabiting vegetated shallow-water habitats 
(U.S. EPA 2003b). As the water clarity criteria will lead to increased water quality and 
an increased forage base for sea turtles, NOAA Fisheries believed that these criteria 
will beneficially affect listed sea turtles. While shortnose sturgeon are not directly 
dependent on underwater grasses, these grasses are an important part of the food chain 
making the protection of bay grasses beneficial to shortnose sturgeon as well. 
DISSOLVED OXYGEN CRITERIA 
SEA TURTLES 
After reviewing the best available information on the status of endangered and 
threatened species under NOAA Fisheries jurisdiction, the environmental baseline 
for the action area, the effects of the action, and the cumulative effects, it was NOAA 
Fisheries’ opinion that the EPA’s approval of the dissolved oxygen criteria for Chesa¬ 
peake Bay and its tidal tributaries was not likely to adversely affect loggerhead, 
leatherback, Kemp’s ridley, green, or hawksbill sea turtles. Because no critical 
habitat is designated in the action area, none will be affected by the project. 
NOAA Fisheries believed that the dissolved oxygen criteria would beneficially affect 
endangered and threatened sea turtles that may be present in the Chesapeake Bay. 
Loggerhead, Kemps ridley, leatherback and green sea turtles are likely to be present 
in the action area. The occurrence of a hawksbill turtle in the area would be a rare 
occurrence. The effect of the dissolved oxygen levels on juvenile and adult turtles 
have been assessed. As turtles are air breathers, there are not likely to be any direct 
effects to sea turtles as a result of these dissolved oxygen criteria. As the dissolved 
oxygen conditions in the Bay were expected to continually improve over the next 
several years until the nutrient and sediment enrichment goals were met, NOAA 
Fisheries anticipated that as habitat conditions improve in the Bay and habitat was 
restored, there would be an increased forage base for sea turtles. 
SHORTNOSE STURGEON 
NOAA Fisheries determined that the water clarity and chlorophyll a criteria were 
expected to improve water quality conditions in the Bay and its tidal tributaries, 
beneficially affecting all native species of the Bay including shortnose sturgeon 
(NOAA Fisheries 2004). While the dissolved oxygen levels authorized by this set of 
criteria may result in some short-term adverse effects to shortnose sturgeon, no 
chronic or lethal effects were expected. 
chapter iv 
Key Findings Published in the NOAA ESA Shortnose Sturgeon Biological Opinion 
