PORTLAND, Ore. – The U.S. Army Corps of Engineers began preparations to manage double-crested cormorants through culling individual adult birds and oiling eggs at East Sand Island. Preparations began after the recent publication of a Record of Decision necessary for implementing the selected alternative in the Corps’ final management plan and Environmental Impact Statement.
In 2014, NOAA Fisheries released a supplemental biological opinion that requires the Corps to develop and implement a Cormorant Management Plan to reduce predation of Endangered Species Act-listed salmon and steelhead by double-crested cormorants in the Columbia River Estuary. Reasonable and Prudent Alternative action 46 in the supplemental BiOp requires the Corps to reduce the number of cormorant breeding pairs on East Sand Island from 14,000 to about 5,600 by 2018. The Corps’ selected action for decreasing predation is listed in the final EIS as alternative C-1.
The double-crested cormorant colony on East Sand Island near the mouth of the Columbia River has increased from 100 pairs in 1989 to approximately 15,000 pairs in 2013.
Before culling begins, field crews will survey the island to determine how the colony is disbursed. Silt fencing was installed to break up dense groups of cormorants into smaller areas, which will help minimize the impacts to non-target species and allow more accurate tracking of the colony population.
Details about how the Corps will implement phase one of the management plan are contained within Chapter 5 of the final EIS at http://www.nwp.usace.army.mil/Missions/Current/CormorantEIS.aspx.
The Portland District will provide regularly scheduled updates to keep the public informed about the Corps’ actions implemented under the management plan to reduce predation on ESA-listed salmon and steelhead by double-crested cormorants. Each Thursday by 9 a.m. the Corps will update results from culling and egg oiling that occurred during the previous week on the Cormorant EIS web page.
The Corps applied for and received a depredation permit from the U.S. Fish and Wildlife Service that authorizes the Corps the take of 3,489 double-crested cormorants and 5,879 nests, 105 Brandt’s cormorants and 10 pelagic cormorants through January 31, 2016. For more information about the USFWS depredation permit, visit
For information about the recently published Record of Decision, visit http://1.usa.gov/1F4nfLk.
Since the late 1990s, the Corps has been monitoring and conducting research on the diet and colony status of double-crested cormorants nesting on East Sand Island. Research included testing a variety of non-lethal techniques such as hazing, social attraction and altering nesting habitats.
Survival rates for ESA-listed fish through the Federal Columbia River Power System to the estuary have greatly increased due to structural and operational improvements made at Corps dams. The rate at which certain birds, including double-crested cormorants, prey on juvenile salmon and steelhead remains high; consequently, NOAA Fisheries requires the Corps to focus on decreasing that rate.