Laserfiche WebLink
<br />Size Distribution of Catfish Removed <br /> <br />Among the three primary gear types, few fish smaller than 200 mm were collected (Figure <br /> <br />3,). Significant differences were detected between mean total length of angler captured and :tyke <br /> <br />net captured channel catfish (Mann Whitney U statistic =5.545, P=0.0005) in 1998. The mean <br /> <br />lengths offish captured with :tyke nets (mean = 377 mm) was greater than lengths offish captured <br /> <br />by angling (mean = 301 mm). Although too few fish were captured with trot lines for a valid <br /> <br />comparison (i.e. only 9 fish captured), the average length was 382 mm (SD=87) compared to 301 <br /> <br />mm (SD=50) for angled catfish. No difference was observed between the mean length of channel <br /> <br />catfish captured by angling and electrofishing in 1998, however, differences were observed in 1999 <br /> <br />(F = 6.03, df= 1, P = 0.01). The absolute difference between the mean lengths offish captured by <br /> <br />electrofishing and angling was slight (i.e., 291 mm and 300 mm for electrofishing and angling, <br /> <br />respectively). The presence of larger fish in :tyke nets and trot lines suggested that electrofishing <br /> <br />and angling may not have effectively sampled the larger channel catfish in the lower Yampa River <br /> <br />in Yampa Canyon. Little variation in total lengths from angler data were observed within fish <br /> <br />captured by reach (Table 6). No differences were observed in the average size of channel catfish <br /> <br />by trip (Figure 4). Five passes were completed in 1999 through treatment reaches and the mean <br /> <br /> <br />total lengths by trip were 298 mm (SD= 38),293 mm (SD=43), 301 mm (SD=50), 315 mm <br /> <br /> <br />(SD=50), and 301 mm (SD=42), respectively for trips one through five. Total length of channel <br /> <br /> <br />catfish collected by electrofishing in 1999 from this study together with electrofishing data <br /> <br /> <br />collected from the Yampa River above Cross Mountain Canyon by Anderson (2000) , showed a <br /> <br /> <br />significant positive linear slope existed in which larger fish were collected upstream (Figure 5). <br /> <br />Mean relative weights of channel catfish captured among gear types and reaches in 1998, <br /> <br />10 <br />