| Frecklebelly madtom | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Family: | Ictaluridae |
| Genus: | Noturus |
| Species: | N. munitus |
| Binomial name | |
| Noturus munitus Suttkus & Taylor, 1965 |
|
The frecklebelly madtom (Noturus munitus) is a species of fish in the Ictaluridae family. It is endemic to the United States. Madtoms are in the genus Noturus, which is a group of catfish prevalent to North America.
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The Noturus munitus (Frecklebelly madtom) is a robust, boldly patterned member of the monophyletic saddled madtom subgenus Rabida.[1] Historically the population thrived in large rivers in the Mobile Basin and Pearl River drainages in the southeastern United States.[2] However, it is currently limited to the Coastal Plain rivers.[3] The species lives exclusively in medium to large rivers free of sedimentation and over gravel shoals.[3] They spawn between June and August while producing 50 to 75 mature eggs in a single clutch size.[3]
All madtoms species, including Noturus munitus have experienced much decline since the 1950s due to channelization, gravel mining, dredging, and siltation. These activities reduce the ability for the species to properly breed and survive. An effective management plan for this species should concentrate on habitat protection and further biological research. A potential plan could include: monitoring species populations, preventing construction of dams, conducting biological research, and developing riparian buffer zones. Once riparian habitat and stream restoration are created and maintained, the reintroduction of Noturus munitus could be possible.
Noturus munitus is a diminutive catfish with a disjunct distribution across the southeastern United States. It is historically known from the Pearl River drainage in MS and LA, the Upper Tombigbee River drainage in MS and AL, the Alabama River and Cahaba River drainages in Al. However, it has been extirpated from the main channel of Tombigbee and Alabama River, and is currently limited to the Coastal Plain rivers.[3] The species lives exclusively in medium to large rivers free of sedimentation and over gravel shoals.[3] N. munitus has declined rapidly since the mid-1950s when river modification began. The loss of gravel substrates and increased levels of sedimentation due to poor agricultural practices have also implicated the species. It is now reliably found in high numbers in only a few locations and is considered threatened with extinction.[2]
The habitats of Noturus munitus and other Noturus species are very specific. They have to have moving, cool water, with no sedimentation. This is why human modification of rivers is such an important subject when it comes to conserving this species and others. Dams interrupt the water regimes, and sedimentation can cover eggs preventing them to hatch. Also, according to research it is typical that large-river specialists frequently cohabitate. In a study published in the Southeastern Naturalist several large-river specialists were frequently collected with N. munitus, including Macrhybopsis sp.cf. aestivalis (Speckled Chub), Macrhybopsis storeriana (Silver Chub), Notropis uranoscopus Suttkus (Skygazing Shiner), Crystallaria asprella (Crystal Darter), Percina lenticula (Freckled Darter), and Percina vigil (saddleback Darter) [4]
Since Noturus. munitus is an opportunistic insectivore, like most of these fish, competition for food may be present in the ecology of the species. A diet analysis published in the Southeastern Naturalist, showed Bactidae nymphs (31%), hydropsychidae larvae (20%), and Simuliidae larvae (20%) provided most of the food volume for N. munitus.[4] Consequently, in the long run, managing for N. munitus would also benefit other species as well. On the other hand, another reason for decline that should be assessed is predators. However, published articles on madtom predators were hard to find. Though, like all madtoms, they are known for their pectoral spines that contain saw-like teeth and a neurotoxin gland. These spines and toxins produce a painful sting when utilized, and indicate the presence of predators.
N. munitus reproduction is similar to those of other madtom species. They spawn between June and August while producing 50 to 75 mature eggs in a single clutch size.[3] They also prefer to make homes in cavities under rocks. They use these cavities for spawning. The male locates and guards a suitable site while the female deposits the eggs. The male then protects the eggs from predators and keeps them clean until they hatch. This is why sedimentation plays such a big role in the decline of the species. Sedimentation can cover the eggs and cause them to die. If successful it will reach reproductive maturity during the second summer of life,[4] and will live 2–3 years.[3]
Of the 29 Noturus species, more than 50% are considered vulnerable, imperiled, or extinct, and many are likely in need of conservation action due to small ranges and increasing anthropogenic threats.[5] Much of this decline is due to human impacts such as: water impoundment, channelization, gravel mining, dredging, and siltation. These activities reduce the ability for the species to properly breed and survive. Its habitat specificity and lack of published research are also affecting further conservation actions. To reduce these human impacts the species needs to be considered for a federal threatened status. They are protected in MS and AL, however not legally protected in LA. The Alabama Forever Wild Land Trust has aimed to protecting habitat sites that would be utilized by N. munitus.[3] However, besides that there is no direct management for the species.
Conservation recommendations include: