An endangered Fish o' the Day - pygmy madtom

As I mentioned earlier, I'll be including some posts authored by students in my summer Biology of Fishes course.  Among their other assignments, they're completing weekly "mini-projects" dealing with a number of topics, including Fish o' the Day in different categories (invasive, endangered, etc.), Fish in Art/Literature, Fish as Food, and others.  A couple from last night's session.

An entry from Jason on the endangered pygmy madtom.

The pygmy madtom (Noturus stanauli) is the smallest member of the family Ictaluridae. This family of fish is easily recognized due to the barbels that extend from its upper jaw. The pygmy reaches a total length of only 2 inches. Coloration of the fish is typically a dark brown on the dorsal side and a solid white on the ventral side. It is believed that they have a short life span of approximately one year, but they may spawn multiple times.

Very little is known about the pygmy due to the lack of success in collecting efforts. In the two Tennnessee rivers that they are known to inhabit, successful collection only occurs 25% of the time for the Duck River and 50% of the time for the Clinch River, making this one of the rarest if not the rarest fish in North America.

Where collection efforts have been successful, it is noted that their habitat is a relatively silt-free zone, with a stable substrate, and a very high water quality. This is probably related to the pygmy madtom’s decline. Siltation resulting from environmental changes in the area and degradation of water quality may have diminished the amount of suitable habitat for this species, leading to a struggle to remain viable. It seems that the pygmy could be going the way of the dodo.

One bright note is that the pygmy madtom has been successfully bred in captivity. On a collection effort for other fish, two pygmy madtoms were collected and transported into an aquarium modified for their environment. Two spawning individuals were observed during this time, and 13 offspring were able to reach adulthood. This could lead to reintroduction to areas as long as the habitat is suitable.

One thing to be noted about the pygmy is that, in the areas where it is found, there is always a diverse assemblage of species around it. In the Clinch River, 80 species of fish and 18 federally listed mussels are associated with it pygmy habitat. In the Duck River, 90 species of fish are associated with it. This leads one to believe that the presence of the pygmy madtom is an indicator of a healthier river and ecosystem.