|
|
Weed shiners are listed as endangered in Iowa. In the spring of 1990, one weed shiner (Notropis texanus) was collected from the Crooked Slough Complex, Pool 13 (river mile 554.3) of the Upper Mississippi River System. Prior to this study, there is no record of weed shiners collected in Pool 13. After the initial collection, a follow-up search for weed shiners was undertaken during fall 1990, and during late summer and fall 1991, to estimate relative abundance at this site. The Crooked Slough collection site was seined on three separate occasions, and 1,840 fish were collected. No additional weed shiners were captured. Therefore, the collection efforts do not support the hypothesis that the Crooked Slough collection...
|
An electrofishing efficiency study was conducted on Navigation Pool 13 of the Upper Mississippi River to determine the effects of four pulse rate and duty cycle combinations on electrofishing catch rate. The four combinations of pulse rate (Hz) and duty cycle (%) tested were 60/25, 60/75, 80/25, and 80 Hz/75%. It was found that all settings were effective in the capture of fishes; however, the catch rates differed among settings (X2 = 24.01 P �0.05) and 60/25 combination captured more fish than the other settings. The 60/25 setting also showed the least variation between samples. Average lengths and length frequencies of largemouth bass (Micropterus salmoides) collected with the four combinations were similar.
|
The purpose of this study was to compare catch characteristics of two commonly used fish sampling gears. This comparison provides information on which to base decisions about deployment of sampling gear and interpretion of data from localized historical sampling. A comparison of fish catch was made between a 10.7-m bag seine and a mini fyke net (MFN) in Upper Mississippi River Pool 13. The MFNs were found to capture a higher number of individuals and to have a higher species diversity than the seine. Comparisons of family catches between the MFN and the seine revealed that the two gear types do not catch family groups in similar proportions (X2 = 117.6 with 5 df, P < or = 0.05). Because MFNs can be set in nearly...
|
Incidental catches of turtles have been recorded since the inception of the Long Term Resource Monitoring Program fisheries component in 1989. Large numbers of turtles have been collected by fyke nets used for fisheries assessments in Navigation Pool 13, Upper Mississippi River. As of November 1992, 560 turtles of nine species and subspecies have been sampled, with the Western painted turtle (Chrysemys picta belli) being the most common. Tailwater sampling, initiated in 1990, has produced the largest concentration of turtles, predominantly map (Graptemys spp.) turtles. Starting in 1992, captured turtles were sexed and measured to determine species vital statistics.
|
|
|
View more...
|
