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Oneida Lake Cormorant Hazing


In order to minimize impacts of cormorant predation on the fish community of Oneida Lake, cormorant management activities have been undertaken since 1998. The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) conducted cormorant management activities from 1998 through 2009. Along with other activities, APHIS conducted "hazing" (non-lethal) in the spring, summer, and fall to move birds off of the lake. Prior to the APHIS management program, as many as 2,700 cormorants had been counted on the lake per day during the fall migration period, while the adult summer resident population had been as high as 900 birds.

Cornell University research indicated that cormorant predation prior to 1998 was having significant negative impacts on sport fish populations of the lake, including yellow perch and walleye. After control efforts by APHIS were implemented, cormorant use of the lake and associated impacts on walleye and perch declined dramatically. The average number of cormorants on the lake during the spring and fall migration period dropped to less than 200 birds per day from 2005-2008, while the resident summer population was consistently less than 150 birds per day.

In 2010 the federal funding was eliminated for the APHIS cormorant management program on Oneida Lake. From 2010-2013, without this federal funding, cormorant management activities on Oneida Lake have been undertaken by the New York State DEC along with a group of citizen volunteers.

2013 Cormorant Hazing Program

The joint DEC and volunteer cormorant hazing program was implemented at Oneida Lake in late August and September 2013. As in the previous three years DEC Fish and Wildlife (F&W) staff and Environmental Conservation Officers (ECO's) from both Regions 6 and 7 were involved with the hazing effort. ECO's conducted hazing every Wednesday of the month while F&W staff conducted hazing each Monday and conducted cormorant counts (with some hazing if time permitted) every Friday of the month. Volunteers conducted sanctioned, non-lethal hazing efforts each Tuesday and Thursday of the week.

Cormorant numbers declined by roughly half following the first DEC hazing effort in late August but increased in mid-September as the migration commenced. Although the number of cormorants ranged from 400 to 600 birds from mid-September through early October, staff feel confident there would have been more cormorants without the hazing effort. Most birds encountered during the latter half of September appeared naive to our hazing efforts, indicating they were new birds to the lake.

A total of 134 cormorants were killed in order to reinforce the hazing efforts and to collect data on what the birds were eating. Gizzard shad and emerald shiners were again an important part of the cormorant diets, but adult yellow perch and panfish comprised a significant portion their diets for most of the month of September. In contrast to previous years, there was only one week (last week of September) in which gizzard shad comprised nearly the entire diet of the cormorants sampled. The size and abundance of young-of-year (YOY) gizzard shad in September appears to have a great influence on their utilization by cormorants at Oneida Lake. In past years when YOY gizzard shad were larger and more abundant, they appeared to serve as a buffer against cormorant predation on other sportfish.

2010 cormorant hazing program

Despite the documented success of the twelve year APHIS cormorant control program on Oneida Lake, funding was eliminated from the Federal budget for 2010. The New York State Department of Environmental Conservation (DEC) could not undertake a similar management program without dramatic reduction of existing programs due to financial constraints and reduced staffing. As a result, no hazing activities were conducted in spring and summer 2010. However, DEC staff was particularly concerned that the fall migration could have significant impacts on the fishery, so a decision was made to attempt some form of fall hazing program. Concerned lake users indicated a willingness to assist in some way, so staff settled on a joint effort conducted by both DEC staff and citizen volunteers. The use of volunteers in cormorant control programs in other states has apparently had mixed results, so this was looked upon as an experimental program to determine the potential effectiveness in New York.

To view the full report: Summary of Fall 2010 Cormorant Hazing Activities at Oneida Lake (PDF) (402 kB)

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