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Not evaluated (IUCN 3.1)
D. S. Jordan, 1878
Minytrema melanops, or spotted suckers, have a dark spot at the base of each scale giving them the appearance of having many rows of small black spots on their body and can reach about 19 inches. They are widely found throughout the central and southeastern United States and reach southern Canada. They are distributed within and east of the Great Lakes and Mississippi River basin but these species are at the southeastern limits of their distribution in the Apalachicola River. The spotted sucker inhabits deep pools of small to medium rivers over clay, sand or gravel. They are occasionally found in creeks and large rivers. Through its life stages, the spotted sucker goes from a mid-depth predator to a bottom forager. There is not much known about the feeding habits of adults. It is believed that suckers feed primarily during dusk and dawn. Spotted suckers primarily feed upon organic fragments, copepods, cladocerans, and chironomids. Other benthic invertebrates have been found in gut contents, but are not a large part of the diet. Spotted suckers spawn in April and May, when water temperatures reach approximately 59 degrees. There is no parental care by the adults. The eggs take 7–10 days to hatch. Early development of Minytrema melanops is quite similar to that of other catostomids. You can identify larvae by fin ray counts, myomere counts, and pigmentation  Limited knowledge of the occurrence, abundance, and natural history of this species has been an impediment to status assessment and the determination of need for conservation measures within this family.
The spotted sucker has a very wide distribution. It is found in the lower great lakes and Mississippi River Basins from Pennsylvania to Minnesota and in Atlantic and Gulf Slope drainages in North Carolina to western Texas. Populations in the United States have remained stable and they are still relatively common. The spotted sucker prefers clean, clear bodies water with a firm substrate. It is reported that they are abundant in oxbow lakes and other areas without a strong current. They do not tolerate pollution or siltation very well and because of this they have been lost in some areas of their historic range such as Illinois. Numbers are also declining in areas such as Ohio and Kansas. Farther north in Canada the species is a species of concern due to declining numbers and deteriorating water quality. This represents the northern most area of their range, so they may have always been rare in Canada.
The feeding habits of Minytrema Melanops show a distinct change throughout its life cycle. As larvae the fish feed upon individual zooplankton. Larvae up to 25 millimeters in length were observed feeding in shallow back waters during the day. The spotted sucker begins to ingest organic matter once they reach approximately 25 millimeters. It is at this length that they become bottom feeders. At about 50 millimeters Minytrema begins to feed on the substrate and benthos and sand become part of the stomach contents. As larvae and juvenile Minytrema feeds in schools, but as they become adults they separate to feed in deeper waters. The stomach content of spotted suckers varies with the time of the year. In the spring, summer, and autumn large numbers of zooplankton are ingested. In the summer and autumn chironomids are also found. This shows the change in abundance with the change in season. Numerically, organic fragments and sand are most abundantly found in the gut. This is followed by diatoms, copepods and cladocerans making up much of the remainder. From the differences in abundance and types of particles in gut contents from different populations, it appears that Minytrema is not selective for any particular group, but harvests those groups that are seasonally or regionally abundant .
Predators of the spotted sucker typically vary depending on the environment. It depends heavily on clean waters with no silt to survive. It prefers sluggish water, but has been found in some turbid environments. Human activities have caused for the streams that Minytrema lives in to become silted, thus making it hard for them to survive. However, dams have also caused impoundments which can cause slower moving waters and boost populations.
Spawning season for the spotted suckers begin anywhere from early march to early may when the water temperature reaches approximately twelve to nineteen degrees Celsius. The fish migrate upstream to smaller tributaries in January to spawn in riffles containing gravel substrates. There are usually two males for every female. As the female approaches, the males bump and prod her in the abdomen. The males then clasp the posterior half of the female between themselves on either dies. They vibrate their caudal sections and head toward the surface. During this time semibouyant eggs are released downstream. The males do not guard the nest a leave after the act of spawning. Both sexes are able to spawn more than once in a season. The eggs will hatch after seven to twelve days depending on the water temperature and will reach sexual maturation after three years. The lifespan is generally six years. However, fish in the southeast and to only live for five years. It is unknown why this is.
In order to reduce human impacts on spotted suckers, we would need to maintain stream water quality. The number one reason that causes a decline in the species is siltation of the water that they inhabit. To decrease this influence we could prevent clear cutting up to rivers and other bodies of water. There is not much being done to manage the species due to the fact that populations are still stable in areas where silt is not a problem. It is not federally listed as endangered or threatened in the United States for this reason. However, In Canada the number of spotted suckers is very low. They are listed as a species of concern and fishermen are asked to report any sightings they have of the fish in order to keep a current count of fish populations. The suckers do not usually hybridize with other species. Over fishing is not a problem for this species either. While they generally taste pretty good to eat, the flesh has a lot of bones making it difficult to clean them. There are not currently any easements that are providing areas of conservation for this species.
The spotted sucker is abundant in its native range. It is a good indicator fish to show good water quality due to its inability to thrive in murky water that contains large amounts of silt. Since it is not currently listed, there is not a management plan for Minytrema melanops. However, we should monitor the species to be sure it’s habitat is not destroyed. Regular sampling in streams that are receiving large amounts of silt pollution, such as Tennessee because of agriculture, with electro shockers and seines is needed to be able to estimate population numbers. Sampling should also be done yearly in areas that are not in immediate danger to ensure that there is not cause for concern and populations are still stable. Another method that should be implemented is education of anglers and the public at large. Doing so will encourage anglers to keep streams clear and discourage any kind of stocking of non-native species. While invasive species do not pose an immediate threat right now, they could potentially compete with the sucker for food sources and habitat if streams became extremely polluted. If the sucker’s habitat became limited due to pollution, the invasive species could possibly move into their refuge areas in order to exploit food sources. This would put the sucker in danger of extinction.
- "Spotted Sucker." Spotted Sucker. Ohio Department of Natural Resources, n.d. Web. 27 Oct. 2013.
- Timothy B. Grabowski, Shawn P. Young, J. Jeffery Isely, and, and Patrick C. Ely, “Age, Growth, and Reproductive Biology of Three Catostomids From the Apalachicola River, Florida.” Journal of Fish and Wildlife Management ( 2012): 223-237.
- David S. White and Kim H. “Foods and Feeding Habits of the Spotted Sucker, Minytrema melanops (Rafinesque).” Haag American Midland Naturalist (1977): 137-146.
- Spotted Sucker." Spotted Sucker. Ohio Department of Natural Resources, n.d. Web. 27 Oct. 2013.
- Coughlan, D. J., B. K. Baker, D. H. Barwiick, A. B. Garner, and W. R. Doby. “Catostomid fishes of the Wateree River, South Carolina.” Southeastern Naturalist(2012): 305-320.
- Forese, Rainer, and Auda K. Ortañez. "Minytrema Melanops (Rafinesque, 1820)." FishBase. N.p., n.d. Web. 17 Nov. 2013.
- "Spotted Sucker Minytrema Melanops." Spotted Sucker Minytrema Melanops. Texas State University - San Marcos, n.d. Web. 17 Nov. 2013.
- "Spotted Sucker." Ontario Government, Ministry of Natural Resources. N.p., 2 May 2013. Web. 17 Nov. 2013.
- "Spotted Sucker." Outdoor Alabama. Alabama Department of Conservation and Natural Resources, n.d. Web. 17 Nov. 2013.
- Etnier, David A., and Wayne C. Starnes. The Fishes of Tennessee. Knoxville: University of Tennessee, 1993. Print.