Up to 100 scale samples per species were 

 taken in Miller Lake. Additional length meas- 

 urements, up to approximately 500 for one 

 species, were recorded for the most abundantly 

 represented species . The remaining fish were 

 counted and weighed in bulk . Total number 

 and total weight of all forage fish were estimated. 

 Total lengths and weights were recorded for all 

 fish from area A and from area B in 1948, 1951 , 

 and 1952 except young-of-the-year specimens 

 and forage fish for which only numbers and bulk 

 weight were noted. Up to 50 scale samples 

 were collected from each species of imfXDrtance 

 except as indicated above. In area B, during 

 the 1949 operation, 50 scale samples were 

 taken from most species and an additional 50 

 length measurements were made if enough 

 fish were available. The remaining fish were 

 counted and weighed collectively by species . 



In addition to the fish collected, the 

 numbers of unrecovered small specimens of 

 some species were estimated and assigned 

 a total weight on the basis of recovered 

 samples in the respective size classes. 



WEIGHT AND SPECIES COMPOSITION 

 OF THE FISH POPULATIONS 



In an analysis of a fishery the determi- 

 nation of the capability of a water to produce 

 fish is of primary importance. The term "fish 

 production" has been employed in the literature 

 to convey two different meanings: 1) the sur- 

 plus of fish available for harvest in any period, 

 and 2) the total fish population present at any 

 one time. In this study the term is used in the 

 latter sense only. Fish production, or standing 

 crop, is considered here in terms of pounds 

 of fish per acre with discussions of size and 

 age -group comjHDSition presented in a later 

 section. The list of fish species in table 1 is 

 complete for the 1948 and 1949 collections in 

 area B but omits the "forage fish" group in the 

 other studies . 



The broad nature of the present studies 

 suggested the grouping of all species under six 

 classifications (predators, game fish, panfish, 

 catfish, rough fish, and forage fish) following 

 the precedent established by the Technical 

 Committee for Fisheries of the Upper Missis- 



sippi River Conservation Committee in its pre- 

 liminary reports on other backwater populations 

 (Uppsr Mississippi River Conservation Com- 

 mittee, 63, 64). Bamickol and Starrett(3) em- 

 ployed grouping of a similar type but pointed 

 out certain inadequacies of the arrangement. 



Re liability of estimates 



Consideration was given to the efficiency 

 of the toxicant application and fish collection in 

 area B during 1951 . Sixteen fin-clipped fish 

 with a minimum length of approximately 6 inches 

 and representing eight species were released 

 prior to application of the toxicant . In addition, 

 one spotted sucker was placed in a wire cage 

 and lowered :o the bottom at the deepest point 

 in the area. A 0.25 -inch -mesh seine 8 feet 

 wide and 35 feet long was weighted on both the 

 lead and float lines and laid flat on the bottom 

 in the deepest water. On the day following the 

 poisoning a 250-foot experimental gill net and 

 a 1-inch bar mesh frame net with a 50-foot 

 lead were set in the enclosed area . 



The condition of the spotted sucker in the 

 cage 3 hours after application of the poison had 

 been completed indicated that death had occurred 

 soon after the toxicant was placed in the water. 

 All of the 16 marked fish were recovered and 

 neither the gill net nor the frame net caught any 

 fish. Only two trout-perch and two small gizzard 

 shad were found in the seine which had been 

 spread on the bottom. Minnows and young-of- 

 the=year crappies placed in a wire cage 56 hours 

 after application of the toxicant showed immediate 

 signs of distress and most of them died within 

 15 minutes. While individual checks on the 

 efficiency of the toxicant application and fish 

 collection were not conclusive because their 

 scope was limited, as a group they indicated 

 a complete kill and a recovery of fish approaching 

 100 percent by weight. Although no checks of 

 this nature were made in the other studies, the 

 procedures were similar and therefore it is 

 probable that comparable efficiency was attained 

 except in Miller Lake. 



At Miller Lake the poisoning was preceded 

 by netting, seining, and fin-clipping operations 

 to check the relative efficiency of nets used in 

 test netting operations. These activities were 



