can some fraction of the young survive in freshwater? Or do the ovigerous females swim all the way to the Gulf of Mexico to reproduce?
Blue Sucker (Cycleptus elongatus)
This species is rarely seen by anglers but when caught it garners attention. It has been given several colorful names such as blackhorse and schooner. This is a big-river fish distributed widely in the Missouri, Mississippi, and Ohio river systems, but it occasionally moves into larger tributaries. Blue Sucker reproductive migrations were
well known before dams were placed on many rivers, but are much reduced today. They were considered by several states to be an endangered or threatened species.
The blue sucker is a slender fish with a small head and mouth, and a long sickle-shaped dorsal fin. The back and sides are dark blue in some individuals but others may appear olive to pinkish. The belly is white. Like most suckers, it feeds on the bottom of rivers consuming a variety of immature insects (of which the Pseudiron mayfly nymph is a likely food item). A moderately large fish, it can weigh more than 20 pounds, but individuals larger than 5 pounds are rare. They spawn in Missouri in April over rock, gravel, and firm sand.
Larval blue suckers were rarely reported prior to the 1990s, probably because of the difficulty in being able to sample the relatively deep and swift water occupied by the young. Trawling is an effective method to capture larval and juvenile blue suckers. Given the efficacy of trawling and improved understanding of where these fish live, they are no longer thought to be rare over some of their range.
Trout-perch (Percopsis omiscomaycus)
This species is an evolutionary intermediate between the Salmoniformes (trouts) and the derived Perciformes (perches). On its back, posterior to the dorsal fin, is a fleshy, rayless structure called an adipose fin. Adipose fins are found on more primitive fishes such as catfishes and trouts. This is a thick-bodied, straw-colored fish with several rows of dusky, brownish spots traversing its sides. There are only two species of trout-perches (family Percopsidae), the other is found in the northwestern United States and is called the sand roller (P. transmontana). Trout-perch is a wide-ranging species found from Alaska to Maine and from the Hudson Bay to Virginia. It is common over most of its range but is uncommon in Missouri. It is best known in Missouri