Dam Removals Benefit Migratory Fishes in Little River, NC

Published:Thursday, February 7, 2008

 

In the spring of 2007, North Carolina State University researchers set up a resistance board weir at the former Lowell Mill Dam site to monitor upstream and downstream migrations. 

Continue reading for the study-

Little River 

The Little River originates in Franklin County, North Carolina, and flows into the Neuse River near Goldsboro 

Three dams have been removed since 1998, while a notched and impassable dam still remain  

Both anadromous species, such as American shad, and year-round resident species, including suckers and gizzard shad, have annual spawning migrations in the river 

The Study

 In the spring of 2007, North Carolina State University researchers set up a resistance board weir at the former Lowell Mill Dam site to monitor upstream and downstream migrations

 

Upstream electrofishing provided additional information on fish locations

 

American shad abundance was compared to two “rule-of-thumb” estimates of run size for a restored population (conservative: 7 adults/ha; optimistic: 124 adults/ha)

 

Eggs and larvae were collected with plankton nets on the Little River and one Buffalo Creek site. 

Results

Migratory American Shad (502), gizzard shad (302), notchlip redhorse (58) were the most abundant fish collected in the weir

Largemouth bass, sunfishes, channel catfish, and additional species were also sampled

 

American & gizzard shad migrated to Atkinson Mill Dam, the maximum extent of restored habitat

 

Flow was important for migrations, as species migrated in highest numbers during increased flow periods

 

Total American shad abundance (508) was higher than the conservative estimate but drastically lower than the optimistic estimate for the reach below of Atkinson Mill Dam

 

American shad spawning was confirmed by eggs and larvae collected both downstream and upstream of the weir site 

 

Conclusions 

Fish, especially migratory species, are utilizing restored habitat following dam removals on the Little River

 

Since dam removals began in 1998, it may be too early to see overall population responses

 

River flow may annually influence the extent that fish migrate upstream and use restored habitat

 

For 2008, the weir will be moved downstream in order to sample the entire river

 

In addition, fish will receive permanent PIT identification tags.  Passive and active tracking of these fish will provide detailed information about migration and spawning habitat

 

Finally, fish passage or hindrance at the notched dam will also be evaluated  

Produced By: 

Joshua K. Raabe, Graduate Research Assistant., PhD candidate

Joseph E. Hightower, Professor, Assistant Unit Leader 

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