Date of this Version
Published in Transactions of the Nebraska Academy of Sciences, Volume 3 (1976).
From September 5,1970 to August 10,1971,27 species and 12,499 fish were collected from the Middle Loup River by seine. The red shiner, Notropis lutrensis, and the sand shiner, Notropis stramineus, composed 72 per cent of the total fish taken. The minnow family, Cyprinidae, composed 88 per cent of the total fish collected. Species diversity and number of species increased with the increase in the size of the river.
Very little research has been done with fish distribution in the rivers of Nebraska. As time goes by, conditions change and so do the fish populations. Thus, it is important that we know what the fish distribution and species composition are today so that we can best manage this resource for future generations.
The Middle Loup River begins in Hooker County northwest of Mullen. It flows mainly in a southeasterly direction. The Middle Loup and South Loup Rivers combine near Boelus and then angle northeasterly until they flow into the North Loup River forming the Loup River.
Methods and Materials
All collections were made with a seine. The collections during the fall of 1970 were made with a 20-foot by 4-foot nylon ¼-inch mesh seine. The collections made during the spring and summer of 1971 were made with a 20-foot by 5-foot nylon ¼-inch mesh bag seine.
As the fish were collected, they were immediately placed in a 6 per cent formalin solution. A few of the fish captured were identified and released.
Fourteen collection stations (Fig. 1) and (Table 1) were selected along the river mainly because of their accessibility. Three different habitats were sampled at most sites. These habitats included the channel water with swift flowing water, side channel with shallow moderate flowing water, and back water formed by the river backing up into pools of various depths. Some of the collection stations toward the headwaters of the river consisted of just one habitat, the channel, because of the narrow width of the river.
Seine hauls made at each station were kept at similar lengths as much as possible. These hauls usually averaged 10 yards. The number of seine hauls made for each habitat at each station did vary. Seine hauls were made until it was felt that a representative sample had been taken. This was determined when no new species were taken in a seine haul.
The keys used in the identification of the fish collected were Eddy (1969) and Cross (1967).