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A small fish with dark stripes on a yellow tinged back and white belly.
Information icon Blackfin sucker. Photo by Matthew Thomas, KDFWR.

Blackfin sucker

Thoburnia atripinnis

  • Taxon: Freshwater fish
  • Range: Upper Barren River system, north-central Tennessee and south-central Kentucky
  • Status: Not listed

Appearance and life history

A small fish averaging about five and a half inches in length, the blackfin sucker has a body patterned with two dark, brownish-black horizontal lines below the lateral line (a faint line of sense organs extending from the gill cover to the tail) and six or seven additional lines in the back and the side of the body, with intervening olive-gold stripes. The lower body surface to the lowest lateral stripe and the belly are white. The top of the blackfin’s body, the single belly fin near the tail, and pelvic, paired belly fins near the head fins are white; the back fin has a conspicuous black blotch on the distal half of the front five or six rays. The paired side fins near the head are pinkish olive. Blackfins reach sexual maturity by three years old with some males maturing by age two. The fish has a maximum lifespan of five years. Female blackfins spawn in March and April.

A fish out of water being held in a net.
Blackfin sucker. Photo by Matthew Thomas, KDFWR.

Habitat

Blackfin suckers are found in clear headwater streams near bedrock ledges, slabrock boulders, root wads, and undercut banks in pools and slow runs. U.S. Fish and Wildlife Service biologists observed that adult suckers were attracted to bedrock ledges, crevices, large rock slabs, and boulders. Adult blackfin suckers also are found in deeper water than sites where the species was not found. Schools of juvenile suckers are found in pools with moderate current and shallower water than the pools occupied by adults. Reproductive males occupy swift riffles, in areas under or behind large rocks several weeks before the females are ready to spawn. During spawning, the females occupy pools and are occasionally found under flat rocks at the edges of riffles.

Diet

The blackfin’s primary food item is larval midges. Other items include crustaceans, larval black flies, larval fishflies and hellgrammites, and larval caddisflies.

Historical range

According to pre-2007 data, the blackfin sucker was historically found in 23 streams in the Upper Barren River Basin.

Blackfin sucker status in all streams of historical or recent occurrence in the Upper Barren River Basin

Sub-Basin Stream Drainage Area Status County of Last Observation
Boyds Creek Boyds Creek 14.5 extant Barren, KY
Skaggs Creek Skaggs Creek 147.0 extant Monroe, KY
Falling Timber 59.7 extant Metcalfe, KY
Glover Creek 22.7 unknown Barren, KY
Nobob Creek 17.4 extant Barren, KY
Peter Creek Peter Creek 69.0 extant Barren, KY
Caney Fork 11.7 extant Barren, KY
East Fork Barren River Indian Creek 33.9 extant Monroe, KY
East Fork Barren River 335.4 extant Monroe, KY
Mill Creek 32.9 extant Monroe, KY
Gully Creek 5.2 extant Monroe, KY
Cable Branch 3.4 likely extant Monroe, KY
Trace Creek 18.3 extant Clay, TN
Line Creek 68.9 extant Clay, TN
Wilson Branch 1.8 likely extant Clay, TN
Hurricane Creek 7.8 likely extant Clay, TN
Salt Lick Creek 52.8 extant Macon, TN
Little Salt Lick Creek 8.4 extant Macon, TN
Long Hungry Creek 14.0 extant Macon, TN
Long Fork 33.0 extant Macon, TN
White Oak Creek 118.5 extant Macon, TN
Puncheon Creek Puncheon Creek 26.8 extant Allen, KY
Pinchgut Creek Pinchgut Creek 7.1 extant Allen, KY
Long Hungry Creek Long Hungry Creek 6.7 unknown Allen, KY
Long Creek Long Creek 69.5 extant Macon, TN
West Fork Long Creek 11.3 extant Macon, TN
Hanging Rock Branch 3.5 extant Macon, TN
Rhoden Creek Rhoden Creek 5.0 extant Allen, KY
Walnut Creek Walnut Creek 4.2 extant Allen, KY

Current range

According to historical and present survey data, the blackfin sucker is extant in 24 streams, likely extant in three streams, and of unknown status in two streams within the Upper Barren River Basin.

Summary of recent Blackfin sucker surveys (2007-2016). Streams are organized by stream and sub-basin (in bold).

Stream Location River km (mi) Watershed size (km2(mi2)) Collection Date # observed
Boyds Creek 7.6 (4.7) 19.9 (7.7) 20091 10
20112 22
20163 15
Skaggs Creek 13.0 (8.1) 122.2 (47.2) 20091 6
20163 17
Falling Timber Creek 10.9 (6.8) 58.5 (22.6) 20091 1
Falling Timber Creek 18.0 (11.2) 17.6 (6.8) 20163 3
Nobob Creek 1.3 (0.8) 45.6 (17.6) 20112 1
Peter Creek 20.9 (13.0) 128.2 (49.5) 20091 2
Caney Fork 1.3 (0.8) 29.3 (11.3) 20112 18
20112 19
20163 12
East Fork Barren River 14.0 (8.7) 91.9 (35.5) 20091 2
18.2 (11.3) 65.3 (25.2) 20163 5
7.9 (4.9) 113.7 (43.9) 20112 2
20134 P5
Indian Creek 1.1 (0.7) 80.0 (30.9) 20112 1
Indian Creek 8.2 (5.1) 51.0 (19.7) 20112 16
20163 4
Mill Creek 4.7 (2.9) 54.4 (21.0) 20091 6
20112 20
20163 16
Gully Creek 0.5 (0.3) 13.2 (5.1) 20094 P5
Line Creek 21.1 (13.1) 54.1 (20.9) 20112 10
20112 4
Trace Creek 6.0 (3.7) 29.8 (11.5) 20112 27
20163 29
Salt Lick Creek 1.4 (0.9) 305.6 (118) 20091 1
Salt Lick Creek 5.0 (3.1) 135.5 (52.3) 20091 5
Salt Lick Creek 16.8 (10.3) 107.2 (41.4) 20112 16
20163 10
Salt Lick Creek 24.0 (14.9) 38.8 (15.0) 20156 8
Little Salt Lick Creek 1.9 (1.2) 16.8 (6.5) 20112 36
Little Salt Lick Creek 3.9 (2.4) 14.5 (5.6) 20112 14
Little Hungry Creek 1.3 (0.8) 33.7 (13.0) 20112 7
Long Fork 8.2 (5.1) 76.7 (29.6) 20112 2
20163 7
Long Fork 19.6 (12.2) 26.9 (10.4) 20112 3
White Oak Creek 10.1 (6.3) 51.0 (19.7) 20112 24
White Oak Creek 13.8 (8.6) 34.7 (13.4) 20107 6
White Oak Creek 19.2 (11.9) 12.2 (4.7) 20112 25
Puncheon Creek 3.5 (2.2) 64.0 (24.7) 20091 1
20163 10
Puncheon Creek 6.1 (3.8) 49.2 (19.0) 20112 3
Puncheon Creek 7.6 (4.7) 33.4 (12.9) 20112 1
Puncheon Creek 8.7 (5.4) 29.3 (11.3) 20126 P5
Puncheon Creek 11.3 (7.0) 23.6 (9.1) 20126 P5
20112 8
Pinchgut Creek 9.8 (6.1) 5.7 (2.2) 20112 10
20163 8
Long Creek 17.9 (11.1) 141.2 (54.5) 20112 1
Long Creek 19.6 (12.2) 130.3 (50.3) 20084 P5
20112 2
Hanging Rock Branch 0.6 (0.4) 8.5 (3.3) 20088 1
West Fork 3.7 (2.3) 20.7 (8.0) 20112 24
20163 8
Rhoden Creek 4.7 (2.9) 11.7 (4.5) 20112 9
Walnut Creek 5.8 (3.6) 8.5 (3.3) 20112 3

Conservation challenges

The blackfin sucker is only found in habitat with rock ledges, crevices, and boulder slabs, and these features are susceptible to sedimentation (built-up material that sinks to the bottom of the water). Excess sediment can bury blackfin habitat, damage fish gills and eggs, and kill or affect the blackfin sucker’s prey.

Degradation, caused primarily by agricultural uses in the Upper Barren River Basin, is the primary threat to blackfin sucker habitat. Stream channelization, along with loss of waterside habitat, bank erosion, sedimentation, and fertilizer and pesticide runoff, can result from agricultural use.

The effects of climate change also may impact blackfin populations. An increase in mean temperature and average annual rainfall within the species’ range, combined with increases in the frequency, duration, and intensity of droughts, could be detrimental.

Reasons for “Not Warranted For Listing” finding

The blackfin sucker was one of 404 aquatic, riparian, and wetland species, petitioned to be listed under Endangered Species Act by the Center for Biological Diversity and others on April 20, 2010.

Existing state laws in Kentucky and Tennessee offer some protection

Under the Tennessee Nongame and Endangered or Threatened Wildlife Species Conservation Act of 1974 (Tennessee Code Annotated §§ 70-8-101-112): “[I]t is unlawful for any person to take, attempt to take, possess, transport, export, process, sell or offer for sale or ship nongame wildlife, or for any common or contract carrier knowingly to transport or receive for shipment nongame wildlife.” Further, regulations included in the Tennessee Wildlife Resources Commission Proclamation 00-14 (Wildlife in Need of Management) (1) prohibits the knowing destruction of habitat of designated species without authorization and (2) provides circumstances for which permits can be given to take, possess, transport, export, ship, remove, capture, or destroy a designated species.

The blackfin sucker and its habitat also get some protection through the following laws: Federal Water Pollution Control Act of 1977, commonly referred to as the Clean Water Act (33 U.S.C. 1251 et seq.); Kentucky’s Forest Conservation Act of 1998 (KRS §§149.330–355); Kentucky’s Agriculture Water Quality Act of 1994 (KRS §§ 224.71–140), additional Kentucky statutes and regulations regarding natural resources and environmental protection (KRS §§ 146.200–360; KRS § 224; 401 KAR §§ 5:026, 5:031), and Tennessee’s Water Quality Control Act of 1977 (T.C.A. 69–3–101).

Threats experienced by the blackfin sucker are not expected to change significantly in the future

Agriculture has been the dominant land use in the Upper Barrens River Basin for more than 150 years, and populations of the blackfin sucker have not declined. Despite the creation of Barren River Lake by a dam in 1964, risks to the blackfin’s genetic diversity are expected to remain the same. However, the effects of the resulting genetic isolation may become more pronounced over time, especially in the smaller populations.

Some of the blackfin sucker’s native predators in the Upper Barren River system include fish such as smallmouth bass, spotted bass, rock bass, and wading birds such as the great blue heron. Predation might increase with the introduction of new predator species. The Kentucky Department of Fish and Wildlife Resources has historically stocked non-native rainbow trout in Peter Creek from Barren River Lake upstream to near Dry Fork. While introduced trout may prey on blackfin suckers, they would only be present during the colder months and would not persist in this region without additional stocking. Kentucky Department of Fish and Wildlife Resources is not currently stocking rainbow trout within the Upper Barren River Basin. Because the blackfin is adapted to living with native predators and the influence of introduced predators is minimal, predation does not likely have a significant effect on blackfin sucker populations.

Climate change, such as an increase in annual temperatures and rainfall, intensified flooding, and increased droughts, is expected to negatively affect the blackfin sucker. However, there is currently no data available to analyze when or if those climatic changes will result in a change in the blackfin sucker’s viability.

The blackfin sucker’s resiliency and ability to survive catastrophic events are estimated as moderate to high

There is a relatively high abundance of blackfin suckers observed in multiple streams during recent (2007-2016) surveys (observations ranging from one to 36, with a median of eight). The blackfin’s resiliency was further demonstrated by the presence of multiple age classes (evidence of recruitment) at many collection sites. All of these observations suggest that there are multiple, self-sustaining, moderately large populations across the species range. The Service’s moderate to high estimate of redundancy is based on the blackfin’s relatively high number of 27 occupied streams that are distributed across nine separate sub-basins in the Upper Barren River watershed. These streams provide a margin of safety for the species to reduce the risk of extirpation from a single catastrophic event. Representation can be measured through genetic diversity within and among populations and the ecological diversity of populations across the blackfin’s range.

The blackfin sucker is extant or likely extant in 27 of 29 streams with previous collection records. It also is extant in nine of the 10 sub-basins with historical records. The blackfin’s status is unknown in the remaining two streams and one sub-basin. The Fish and Wildlife Service cannot conclude that the blackfin sucker is currently extirpated from any portion of its historical range.

Federal Register notices

The following Federal Register documents were automatically gathered by searching the Federal Register Official API with this species’ scientific name ordered by relevance. You can conduct your own search on the Federal Register website.


  1. Stillings and Harrel (2010). Date of record is listed as 2009; actual date may be 2009 or 2010. [return]
  2. Stringfield (2013). Date of record is listed as 2011; actual date may be 2011 or 2012. [return]
  3. USFWS (2016). [return]
  4. KDFWR (2016). [return]
  5. P = Indicates record of presence with no recorded number of individuals. [return]
  6. TWRA (2016). [return]
  7. Johansen (2010). [return]
  8. TDEC (2017). [return]
  • We're sorry but an error occurred. Visit the Federal Register to conduct your own search.

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