19 
In addition, NOAA Fisheries determined that the adoption of the dissolved oxygen 
criteria would result in significantly improved water quality conditions in the Bay, 
elimination of anoxic zones and the improvement in the quality and quantity of 
habitat available to shortnose sturgeon as well as improving the chances for recovery 
of the Chesapeake Bay population of shortnose sturgeon and the long term sustain¬ 
ability of this population (NOAA National Marine Fisheries Service 2004). 
This determination was based on the following conclusions: 
• The effects of the ambient water quality criteria for the Chesapeake Bay and its 
tidal tributaries have been analyzed on the Chesapeake Bay population of short¬ 
nose sturgeon. While the dissolved oxygen levels authorized by this set of criteria 
may result in some short-term adverse effects to shortnose sturgeon through 
displacement or other behavioral or physiological adjustments, no chronic effects 
are expected. No lethal effects are expected as a result of the dissolved oxygen 
criteria and significant protections are being provided to essential habitats 
including deep water, spawning and nursery habitats. 
• The adoption of the dissolved oxygen criteria will result in significantly improved 
water quality conditions in the Bay, elimination of anoxic zones and the improve¬ 
ment in the quality and quantity of habitat available to shortnose sturgeon as well 
as improving the chances for shortnose sturgeon recovery in the Bay and 
improving the likelihood of long-term sustainability of this population. 
• NOAA Fisheries believes that the issuance of these criteria, as currently stated, 
would not reduce the reproduction, numbers and distribution of the Chesapeake 
Bay shortnose sturgeon population or the species as a whole in a way that appre¬ 
ciably reduces the likelihood of the species’ survival and recovery in the wild. 
This conclusion was supported by the following: (1) no lethal takes of any life 
stage of shortnose sturgeon are anticipated to occur; (2) the demonstrated ability 
of shortnose sturgeon to avoid hypoxic areas and move to areas with suitable 
dissolved oxygen levels; (3) the availability of adequate habitat with not only 
suitable temperature, salinity and depth, but suitable dissolved oxygen levels; (4) 
the seasonal nature of the anticipated effects (i.e., no effects anticipated from 
October 1-May 31 of any year); (5) adequate protection of essential spawning and 
nursery areas protecting not only spawning adults but eggs and larvae from 
hypoxic conditions; (6) the elimination of anoxic areas within the Bay; (7) a large 
portion of the deep-water areas have low temperatures and adequate dissolved 
oxygen levels allowing shortnose sturgeon to be less dependent on the deepest 
areas of the Chesapeake Bay (deep-channels) for thermal refiigia; and (8) the 
significant improvement in Bay water quality conditions and increased avail¬ 
ability of suitable habitat for all life stages of shortnose sturgeon. 
As such, it was NOAA Fisheries’ biological opinion that the approval of these 
criteria by EPA may adversely affect the Chesapeake Bay population of endangered 
shortnose sturgeon through displacement to suboptimal habitat or other behavioral 
and metabolic responses to hypoxic conditions but was not likely to jeopardize the 
chapter iv 
Key Findings Published in the NOAA ESA Shortnose Sturgeon Biological Opinion 
