u SEA LAMPREY SPAWNING RUNS IN THE GREAT LAKES, 1950 SPECIAL SCIENTIFIC REPORT: FISHERIES No. 61 Marint JUl, WOODS i UNITED STATES DEPARTMENT OF THE INTi FISH AND WILDLIFE SERVICE Explanatory ^ote The series embodies results of investigations, usually of restricted scope, intended to aid or direct management or utilization practices and as guides for administrative or legislative action. It is issued in limited quantities for the official use of Federal, State or cooperating agencies and in processed form for economy and to avoid delay in publication. Washington, D. C. April, 1950 Interior - Duplicating Section, Washington 25, D.C. United States Department of the Interior, Oscar L. Chapman, Secretary- Fish and Wildlife Service, Albert M. Day, Director SEA LAMPREY SPAWNING RUNS IN THE GREAT LAKES IN 1950 by Vernon C. Applegate and Bernard R. Smith Fishery Biologists Special Scientific Report, Fisheries Uo. 6l CONTENTS Page Introduction i Installation and operation of sea lamprey CO nT-rO-L StrilC OUT eS Xn Xy y\) eooooeeoooooooo^oeoaeoooe 1 Lake Michigan •ooo»»>>o»" oooaooooooooooooooo^oo.oo.o.. i> lalCS SliperiOT' ©•O3«ooooooo*>oo»oo«vo3«o»©«coo©oo&»oepo o Number, of lampreys -taken by control devices -»*<>..«...<> 6 Relative abundance of sea lampreys c.ooo»ooo.o<.oeoe<.oo 6 X.3JC6 flLUrOn g0OOOOO«OCMOO6OCOO.}OOOOOC0OQOOO06eOOOOQO0 O J_)di\*S ] il < ■> " t g/ -T- fl o^OOOOOOeOOOe<>Ci0000000000000009000«0000 W IjcIKS OllpG riOr ooooouooooooeoooooooooceoooooooooooooos y Other species of fish taken in the weirs and traps and degree of scarring among them „ . « „ » . © © . . . . . . . . . . © 9 Some biological characteristics of the sea lamprey X Lillo 00-7000000000000000000 ooooooooooosooooo o o c o o o oooo — i- O C A I (_*. U'_L O OOOOOOOOOOO OOOOOOOOOOOOOOOO 'OOOCOOOOOOOOOOO*-i-£. Range in length and average size, of migrant adult Sea a.dnlpr6jr S oooooooooooooqooooooooooooooooooooooooo* -LLJ. Characteristics of spawning runs and their response to the several factors affecting them <> ill Variations in time and character of migration in different streams of differing characteristics X 1 1 ^-lC SeAIuS /jOfltf oooooooooOoooooooQooooooooooeoooooo • ^- 5 Variations in the tine of migration in different areas (latitudes) of the same lake and among QIX X GrGf. J X. oK6S OOOOOOOOOOOOOOOOOOOOttOOOOOOCOOOOOOOOS^f Movement and dispersion of a blocked spawning run OJ. Otti X dl'l^Jl CjS ooooooooooooooooooooooooooooooeoooooo C. / Evaluation of various types of mechanical control U.CVl.Co OOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOQOOOOO O o O o o * © _,' U J— j_ L'tl d vUi 6 -^1 L> GCi ooooooooooooo«eooooeooooooooeoooooceo0 i-iO List of common and scientific names of fishes mentioned in this report oo«ooooeooooooeoo.ooo.»o.©o Ii9 ILLUSTRATIONS FIGURE PAGE lo Map of upper Great Lakes showing established sea lamprey 2. Map of northern Lake Huron and Straits of Mackinaw showing location of weirs and traps in Control Zone H-i . . 3 3. Portable-type weir and trap in Milligan Creek, Presque J. s x c vO un iy * in cni^ a. n 0«o*«o***eo«e*«ss«o««o*««*»«*»**««0» /4 lu Small portable-type weir and trap in Cedar Creek, Presque Isle County, Michigan h 5. Large portable-type weir and trap in Pendill's Creek Chippewa County, Michigan 5 6. No. of sea lampreys taken each day during 1950 season in five northern Lake Huron tributaries of different size and character, and mean stream water temperatures for period „ 26 7. No. of ssa lampreys taken each day during the 1950 season in five streams in different geographic latitudes with mean stream water temperatures for period 28 8. Power dam in Cheboygan River at Cheboygan, Michigan 31 9. Peterson-type tag applied to migrant sea lamprey 32 10. Small-scale chart of upper Great Lakes showing general dispersion of marked lampreys from blockaded spawning 11. Large-scale chart of Control Zone H-l (northern Lake Huron) showing movements of marked lampreys from blockaded Cheboygan River spawni ng run 33 12. Permanent- type sea lamprey xjeir and trap in Ocqueoc River, Presque Isle County, Michigan 39 13. Dam and inclined-screen sea lamprey trap in Carp Lake River, Emmet County, Michigan 39 ILLUSTRATIONS (con't) FIGURE PAGE llio Diagrammatic plans of the Carp Creek style portable- type sea lamprey weir and trap ...... . .................. . Ul 1?. Diagrammatic plans of the Milligan Creek style portable- type s ea lamprey weir and trap ....... ........ .......... 1|2 16. Perspective drawing of Carp Lake River dam and inclined- 17. Digrammatic plans of a sea lamprey barrier dam rein- forcing details not shown .................. ............ Ixb Introduc tion As the result of a special Congressional appropriation (Public law 2u9-8lst Congress) the Service's sea lamprey investigations were greatly expanded at the beginning of the 1950 calendar year. A per- manent staff of seventeen individuals with an equal number of seasonal employees was assigned specifically to these investigations. Permission to occupy the former Hammond Bay Coast Guard Station on northern Lake Huron was obtained from that agency and the nine buildings and other properties involved are now known as the Hammond Bay Fishery Laboratory. Alterations and additions to provide office and laboratory space, run- ning-water aquaria and tank rooms, work shop, net-shop, boathouse, and raceway facilities have been completed or are in progress. Considerable time and energy have been expended to equip this field station and in training the permanent staff. A number of investigations of both the biology of the sea lamprey and of methods of controlling that parasite are currently underway. This report is the first of a series describing the results of one group of studies and activities brought to a conclusion during the 1950 season. Subsequent reports will treat other phases of the work. Installation and operation of sea lamprey control structures in 19 $0 Lake Huron . — In northern Lake Huron 11 weirs and traps were operated in an area which was termed Control Zone H-l. This zone extends a dis- tance of about 90 miles from Waugochance Point at the west end of the Straits of Mackinaw to the southern boundary of Presque Isle County, Michigan (Figs. 1 and 2). Weirs were placed in every stream in this zone in which sea lampreys were known to run. Among these structures were the Ocqueoc River and Carp Creek weirs which were operated in former years. During the 1950 season these two traps were run cooperatively with the Michigan Department of Conservation by crews made up of employees of both agencies. With the exception of the permanent- type Ocqueoc weir all others installed were standard, portable-type sea lamprey weirs (Figures 3, 4, and 5). Complete runs were captured in all but two streams and in these, only a minor escapement occurred. The objectives in establishing this "control zone" were manifold and may be briefly outlined as follows: (1) To institute immediately a measure of sea lamprey control on an organized basis. Experience gained from such an operation would be, and was, invaluable in revealing administrative and operational problems which would present themselves in a large-scale control program; (2) To determine whether destroying the potential to produce sea lampreys in the streams tributary to a limited area of shoreline would Figure I. --Map of upper Great Lakes showinp established and proposed sea lamprey control devices. Figure 3, — Portable-type weir in Milligan Creek, Presque Isle County, Michigan Figure 4.. — Small portable-type weir and trap in Cedar Creek , Presque Isle County, Michigan Figure 5» — Large portable-type weir and trap in Pendill's Creek, Chippewa County, Michigan. have any local beneficial effects on fish stocks in the lakes (3) To develop and test improvements in the design and construction of mechanical control structures} and, (4) To provide needed additional sites where adequate checking struc- tures (weirs and traps) were present for testing other devices or techniques of control Continued operation of the devices in this zone in future years is essential to the successful attainment of all objectives sought. Lake Michigan — In Lake Michigan the Service contributed materials and technical assistance for construction of 7 portable-type weirs and traps operated by the Wisconsin Conservation Department, Entire runs were captured by most of these weirs. In some streams only part of the runs1 were taken since inadequate knowledge of the spawning grounds resulted in the location of the trapping devices too far upstream. Re-location -of improperly placed weirs was effected by the Wisconsin Conservation Department during the summer of 1950. One Dortable-type trap was subsidized by the Service for operation in Trail Creek near Michigan City, Indiana, by the Indiana Conservation Department. Only a portion of the run was captured due to frequent flood damage and operation by inexperienced personnel. One portable-type weir and trap was installed in the Black River, Mackinaw County (Upper Peninsula s^ore of Lake Michigan) for operation by Michigan Department of Conservation personnel as a checking device in an experiment on the effectiveness of a barrier dam for blocking the up- stream movement of sea lampreys. The operation of this weir was inter- mittent; it is estimated that 50 percent of the run was captured. The Michigan, Wisconsin, and Indiana Conservation Departments have kindly permitted us to utilize much or all of the data collected by them in preparing subsequent sections of this report. Lake Superior. — In Lake Superior a weir and trap in Pendill's Creek, a tributary of Witefish Bay, captured the entire run. Subsequent to the spawning-run season, another weir and trap were installed in the Chocolay River near Marquette. This structure will serve as a check on the effect- iveness of an electric fish screen which is in place and is to be tested in the spring of 1951* Numbers of lampreys taken by control devices. — A total of l;8,89l; spawning-run sea lanpreys were captured in 1950 in 21 trapping devices (exclusive of 2,8£i3_) individuals captured and released in a tagging experiment). Biological data were recorded for many of these lampreys; all individuals were subsequently destroyed. These catches are summar- ized in Table 1. Individual totals are given for streams in which trap- ping devices were operated directly by the Fish and Wildlife Service or cooperatively with the Michigan Conservation Department. Gross totals only are given for trapping operations effected with other agencies. Relative abundance of sea lampreys Lake Huron.— In northern Lake Huron weir and itrap catches^ suggest a leveling-off or even a slight diminution in the sea lamprey population in that area. The total run in the Ocqueoc River in 19U9 was 2U,61j3 lampreys; that in 1950 was 18,882. Tagging studies indicated that an appreciable portion of the Ocqueoc River run in 1950 was "siphoned off" through the operation of weirs in all other nearby streams. If this fact is taken into consideration, the numbers in the 19U9 and 1950 runs in this stream may be said to be nearly equal. Weir operations, fishing operations in the lake, and contacts with commercial fishermen Table 1. --Numbers of spawning-run sea lampreys taken by control devices during 1950 season. (Structure designated by number may be located on map in Figure"!"] Stream Total taken Lake Huron tributaries: Control Zone H-l: 1. Carp Lake River, Emmet County 3,821 2. Martins Creek, Cheboygan County 3 3. Little Black River, Cheboygan County 953 h. Elliott Creek, Cheboygan County 266 5. Green Creek, Cheboygan ^ounty l,9h5 6. Milligan Creek, Presque Isle County 700 7. Cedar Creek, Presque Isle County 0 8. Grace Harbor Creek, Presque Isle County 52 9o Garp Creek, Presque Isle County l,l6l 10. Ocqueoc River, Presque Isle County 18,822 11. Trout River, Presque Isle County 1,702 Total-Control Zone H-l Z9,bZS Lake Michigan tributaries: 12. Black River, ^ackinaw bounty 2,lhk Seven weirs operated cooperatively with the Wisconsin Conservation Department 16,391 One weir operated cooperatively with the Indiana Conservation Department 896 Total - Lake Michigan 19,1)31 Lake Superior tributaries: Pendili's Creek, Chippewa County 38 Grand Total U8, 89I1 indicate that fish stocks in the area are sorely reduced, somewhat almost to the point of disappearance. A decline in the sea lamprey population would be a natural sequel to the recently observed abrupt decline of avail- able prey species. As a matter of historical interest and as an aid in predicting the future status of this parasite in Lakes Michigan and Superior, all available records of the spawning runs entering the Ocqueoc River are assembled herewith. (This run was first observed and reported in 1937 by Conservation Officer Marvin Norton according to Shetter (I9h9) . Year Numbers trapped or enumerated 19hh 1/ 3,366 19 h$ y U,6o8 19ii6 (NO DATA) 19 hi 2/ 10,000 19U8 2/ 13,000 19h9 1/ 2U,6U3 1950 18,882 Lake Michigan. — Whereas the population in Lake Huron appears to have at least leveled off, Wisconsin Conservation Department reports for Hibbard Creek in Door County reflect a near trebling of the population in north- western Lake Michigai over 19U9 levels . This point is illustrated in the following records of weir and trap catches of spawning migrants 3/ in the afore-mentioned stream over a U-year period. 1/ Shetter (19li9); partial capture of run; examination of Shetter' s data suggests that these catches represent about three-quarters of the run enter- ing in each year. 2/ -kpplegate (193>0); data for 19h7 and 19^8 are estimates from counts of total number of nests in watershed with consideration given for observed spawning habits and sex ratio in those years; catch in 19U9 is entire run taken in new permanent-type Ocqueoc River weir and trap. 3/ Data for \9h$-\9\\b provided by Mr. Matt Patterson of the Wisconsin Con- servation Department. The number of lampreys trapped in 19U5 is not the complete run into the stream; trapping operations were intermittent in that year. 3/ Data for 19^7-19^9 extracted from Wisconsin's report in the "Report of the Great Lakes Sea Lamprey Committee- 19^7 ," "Report of the Great Lakes Sea Lamprey Committee-19li8/' and "Report of the Great Lakes Sea Lamprey Committee-19li9, " (Mimeographed). 8 Year Number trapped !9hS 25 19U6 125 19U7 596 19U8 989 19h9 1,579 1950 5,U22 Whether or not the sea lamprey had reached the peak of its abundance in Lake Michigan will not be revealed until the conclusion 1 of the 195l season. Judging, however, by the rate of decline of the lake trout (an apparently preferred prey species) in this lake, the time when the demand for food far exceeds the supply is fast approaching. Lake Superior.— In Lake Superior, stream survey reports and records of occur - rence in the Lake proper indicate that the lamprey is more firmly entrenched than heretofore suspected and, although still not numerous, is on the increase. The presence of spawning runs in streams tributary to the southeastern area of the lake is definitely established. Adults have been captured throughout the lake to its extreme western end. In August 1950, representatives of the Minnesota Conservation Department captured mature spawning migrants in several streams in the vicinity of Duluth, Minnisota. Further expansion of the sea lamprey population in Lake Superior may be anticipated. Although adult sea lampreys or their nests were found in slightly less than 10 percent of the 325 streams on the southeastern shore of the lake examined in 1950, rougMy one-third' of the streams in the area are' of a character suitable for sea lamprey reproduction, h/ Utilization of these watersheds by the lamprey may be expected in the near future if the characteristic rate of increase of the species after establishment in a new water (as evidenced in Lakes Huron and Michigan) is displayed. Other species of fish taken in weirs and traps and degree of scarring among them Counts by species were made of fish in 10 of the weirs and traps in Control Zone H-l in northern Lake Huron and in Pendill's Creek which flows into Lake Superior. A total of 103,5Uii fish were taken along with the sea lampreys in the 10 streams of Zone H-l; in Pendill's Creek, 1,2U3 were captured (Table2). Data were collected also on the numbers of lamprey-scarred suckers of several species taken in eight of the streams in Zone H-l and in Pendill's Creek (Table! 3). Scarring records for other species were incomplete. The data presented in this section not only reflect the continuing decline of certain species but also contain a hint that the balance among the remaining fish stocks in this area of Lake Huron may have been profoundly affected by the sea lamprey. h/ A detailed report of a survey of streams tributary to Lake Superior which was conducted in 1950 is now in preparation. 01 £ fl •dl 5 ■M a o H ■ i — 1 CO CD C C a o o a> 3 co % rH •5 +j 8 CO - — -p 3 co i3 \C\ oj b 3> c O H .-: Si CI -h 0) u\ u Ih P 3 _li wl-o [Q Q ok-» 3 ^'.g """ ! rg ,2 •H CO 'H a tl cfl o ^J1 col $ ■ — CO C|>! J-. •HI Q Q) .O £ 21 CD su m 1 (-"■ •" 1 E:i r-j • cfl p-! 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J3 O *£ 2 s 5=» 's— ** 13 CD 7J & -P cd O u e-i 43 CO CD f-f -P -0 Q C O H ; CD O Uo Cn 00 H cn cn cn a CN IT\ 4) w CD CD ' > o o 3) CO Hi o rH Cn CO cn C* 8 cr CQ CD a> -3 . as c o O CD 0) h y CO CfM O O o cn lf\ 33 CD U a. o o 3 C,- CO ►-, M CO o c^v ~4 tX) m en CD O O CD r-i CO U M o CD co 5* QO CO ■H CD h a, -H s o a o o en o en vO 00 o> m C -? 00 m O CN 4 cn r-i o o a) io 0) 5C CD O o CD O cy o o « to ha - t» -P o -p ,0 O CD CD Comparison of weir catches of the larger fishes (food, game and coarse species) with those of former years reflects a drastic decline in the size of their spawning runs (Applegate 1950). Concurrently with this decline, the percentage of lamorey-scarred individuals has increased, for example, in Carp Creek and the Ocqueoc River (Control Zone H-l) the spawning runs of suckers and the number and percentage of lamorey-scarred individuals among them over a U-year period were as follows t Stream Year Total suckers taken Percentage of suckers (all species) scarred Carp Creek 19U7 3,700 7.0 Carp Creek 19u8 2,8h8 6.8 Carp Creek 19U9 1,811 17.2 Carp Creek 1950 161 31.1 Ocqueoc River 19u9 3,137 25.5 Ocqueoc River 1950 331 30.0 The decline of these runs most certainly reflects a severe de- pletion of the stocks of suckers in the lake proper. Fishing operations conducted in this area of the lake substantiate this view. It may be reiterated here that the decline of these and other species of fishes has been coincident with, and (directly) proportional to, the increase in the numbers of sea lampreys (see text table, p.8 ). On the other hand, the numbers of smaller species of fish, primarily cyprinids and presumably forage species, seem to have increased each year. For example, the numbers of Great Lakes longnose dace taken in the Carp Creek weir and t rap over a u-year period were as follows: 19h7-80lij 19U8-5,798j 19li9-l5,69l^ and 1950-30,028. These minnows, too small to be preyed upon by the sea lamprey and in the absence of any effective numbers of their normal predators, appear to be increasing apace. Some biological characteristics of the sea lamprey runs Sex ratio . --Records of sex were made for all or nearly all of the sea lampreys taken in eight streams in Control Zone H-l and in one stream tributary to Lake Superior (Table I4.). Examination of these data col- lected in 1950 indicates that the sex ratio of entire runs in northern Lake Huron continues to shift in favor of the males. Specific figures for four consecutive years are as follows (where data for runs in more than one stream are available, an average has been obtained for the combined runs),, I ear I9UT 19U8 1/1*9 1950 12 Sex Ratio 165 males : 100 females 169 males : 100 females 211 males : 100 females 252 males : 100 females Table lio== Sex ratio of sea lamprey runs in eight tributaries of northern Lake Huron and one of Lake Superior during 1950 season. STREAM TOTAL CATCH TOTAL FOR "WHICH S5JC DETERMINED NO. OF MO. OF RATIO OF MALES MALES FEMALES TO FEMALES Jake Huron; Control Zone H-l Trout River, Pres. Isle, Co, Ocqueoc River, Pres. Isle, Co. Carp Creek, Pres. isle, Co. Grace Harbor Cr., Pres. Isle, lo. Green Creek, Cheboygan Co. Carp Lake River, Emmet Co. Little Black River, Cheboygan, Co. Elliott's Creek, Cheboygan, Co. TOTAL 1,703 1,703 1,206 U97 21*3:100 18,822 18,065 12,9U6 5,119 253slOO 1,161 1,161 863 298 290:100 52 51 Ul 10 UlOslOO 1,91*5 1,325 99$ 330 302 j 100 3,821 3,821 2,666 1,155 231:100 953 751* 522 232 2 25s 100 266 208 157 51 308 % 00 28,723 27,088 19,396 7,692 252:100 Lake Superiors Pendill's Creek, Chippewa, Co. 38 38 20 18 111:100 13 It is possibly significant that in Pendill's Creek, in the Lake Superior basin, where the species is relatively recently established, the sex ratio of the run was 111 males : 100 females. Range in length and average size of migrant adult sea lampreys . — The range in length of 5,287 migrant sea lampreys, sexes combined, that were measured in 1950 was 9.9 to 22.9 inches. The average length, sexes separately or combined, varied a little among the two runs studied but was generally close to a mean of 16,5 inches (Tables 5, 6, and 7). These data were collected in Carp Creek and the Ocqueoc River according to a predetermined sampling schedule: 57.5 percent of the Carp Creek run and 2Lu5 percent of the Ocqueoc River run were measured. Although a slight decline in average length was observed this year for these two runs, the difference was not significant. This year's runs did, however, include a number of individuals of a smaller size than had ever been encountered in three earlier years. Prior to 1950, 10,iill migrant adults from these two streams had been measured. The extreme range in length of this sample was 11.0 to 23.5 inches of vhich only eight individuals measured less than 12.0 inches (Applegate, 1950). In 1950, among 5,287 sea lampreys the total length of 17 individuals were less than 12.0 inches. The range in size of migrant adults is being followed closely for any significant decline in size would seriously affect the structural requirements of mechanical control devices. A decrease in average length of the sea lamprey must be considered possible in the presence of a declining food supply. Characteristics of spanning runs and their response to the several factors affecting them. --Other than in the matter of the sex ratio, as previously noted, the spawning runs in the Ocqueoc River and Carp Creek did not differ in character or in their response to certain environmental factors from those runs of former years (Tables 6, 7, and 8)„ Differences in migrations related to sex and size were again ap- parent. The percentage of males was relatively greater at the begin- ning of the run. The relative abundance of females was greater toward the end of the run, although they never approached the males in total number, The largest individuals of both sexes appeared early in the runs and the average size of migrants declined during the period of movement „ Upstream migration into the weirs commenced when the mean daily water temperature rose above U0°F.j it was sporadic or light close to that temperature. Movement increased as daily mean of 50°F. was ap- proached and the greatest numbers migrated at temperatures above the 50eF. level. lU Table 5.- -Length-frequency of sea lampre we collected in Carp Creek and th; 3 Deque oc River, Presque Isle County, Mich. :ize groups) , in 1950. (Data presen bed by 0.2-incn : Midpoint o.f length Carp Creek Ocqueoc River group Males Fera! -QS Total Male 3 Females Total (inches) — 9.9 y • • » * * ♦ 1 10. 1 > • * • • • » • 4 .3 • • ► « • • • « a .5 t ■ 9 i • • • • • • • • « .7 i • • ..1 • • c 1 .9 • • ► • • « • « 0 11.1 > • • 3 1 4 .3 • 3 l> • . • • • • * • • • t> • 5 • • 3 • • • 3 .7 * * » < • • 2 4 6 =9 6 «- t 1 • • 2 • • • 2 12.1 • > » • » 7 * • • 7 .3 • • * 1 ] 7 3 10 .5 1 • • ] 14 1 15 .7 » * * i • » • • < 24 1 25 .9 3 • * * 5 30 10 40 13.1 3 • • 0 J 36 11 47 .3 6 « • t 33 9 42 .5 12 1 i: 5 59 20 79 .7 2 1 ; ) 66 16 82 .9 u 3 r 1 78 16 94 14.1 11 3 1/! ► 87 22 109 • 3 20 2 2i I 96 35 131 .5 16 4 2( ) 104 31 135 .7 16 1 lr r 106 31 137 .9 17 5 21 > 138 42 ISO 15.1 16 5 2] 94 28 122 .3 16 6 2; > 102 49 151 .5 37 9 M > 142 55 197 .7 21 4 2f > 148 55 203 .9 32 14 4< > 131 63 194 16.1 18 3 2] 111 46 157 »3 11 6 lr t 124 67 191 .5 37 9 4c > 138 53 191 .7 13 4 lr ' 130 45 175 o9 16 16 32 ! 128 55 183 17.1 19 4 2: i 90 43 133 Continued ©n next page 15 Table 5, continued Midpoint of length- Carp Greek Ocqueoc River group Males Females Total Males Females Total (inches) 17 *3 8 5 13 87 45 132 .5 18 5 23 96 46 142 .7 11 4 15 95 37 132 .9 15 6 21 101 56 157 18.1 14 7 21 75 39 114 .3 15 1 16 67 28 95 .5 14 4 18 87 51 138 .7 5 2 7 67 37 104 o9 9 5 14 94 39 133 19.1 A 4 8 44 31 75 • 3 A 4 8 49 23 72 .5 8 3 11 44 18 62 .7 6 1 7 33 10 43 •9 6 2 8 22 17 39 20.1 2 2 4 19 22 41 .3 3 1 4 14 16 30 • 5 2 1 3 16 4 20 .7 1 2 3 9 3 12 .9 2 1 3 4 5 9 21.1 1 • • • 1 6 3 9 .3 1 « • • 1 4 2 6 .5 • • • ■ • « • • • 1 2 3 .7 ■ a • • • k • • • 1 • • • 1 • V • • • 1 1 2 • • • 2 23.1 • « • • • • • • * • * • 1 1 Total 506 162 668 3,271 1,348 4,619 Mean Length 16.4 16.9 16.5 16.4 16.7 16.5 Stand. Deviation 1.78 1.75 1.76 1.89 1.86 1.38 16 Table 6. — Mean v^ater temperatures , number and average len g th by sexes of samples of sea lampreys and total number of sea lampreys taken in Carp Greek Pre s que Isle County, Mich* , by dates and by periods in 1950 Males Female; Date 1950 Mean water tempera- ture /t-.0\ A" Number Average measured length (inches) Number Average measured length (inches) Number not Total measured number taken April 26-May 2 (Weir operation continuous - no lampreys taken) May 3 4 5 May 1-5 May 15 11-15 43.0 41.0 43.0 56.0 1 2 17.6 • » • 17.4 17.5 2 2 19.0 19.0 43 16.7 21 16.9 31 31 3 5 6 47.5 1 14.7 • • • * 1 7 43.0 • • • * • • • * « « • • • • 8 43.5 • • • « • • t • • • • • • • • 9 46.5 • • • • a • • • • • • • • • 10 46.5 1 17.6 • • • • 1 May 6-10 • • • 2 16.2 • • • • < 2 11 47.5 2 19.3 2 17.7 4 12 50.0 5 15.9 2 18.6 7 13 56.0 10 16.7 3 16.6 13 14 56.0 26 16.6 14 16.6 40 31 95 16 17 18 19 20 May 16-20 58.5 52.0 53.5 54.0 58.0 6 17.9 • « • 20 • • • 16.5 • • • 106 132 16.4 16.4 • • • 73 • • • 16.9 ♦ • • 62 15.9 135 16.4 64 16.5 • • • 13 « e • 16.2 • • • 25 • • • 16.0 102 16.3 7 1 ■ • • 32 40 17.9 • o • 17.6 • ♦ • 16.8 17.0 24 38 • • * 46 13 121 37 38 21 46 151 293 21 22 23 24 25 May 21-25 63.0 62.5 59.5 62.0 64.0 23 15 ■ • • 38 17.7 • • • 16.4 • • • 17.2 25 • • • 83 • • * 79 187 25 96 83 77 79 360 May 26 27 28 29 30 31 26-31 64.5 56.0 56.0 61.0 65.0 63.0 20 • • « 6 • • • 6 ■ u a 32 16.6 • • • 17.7 • • • 16.6 • • • 16.8 Continued next page 45 32 • • • 12 89 84 45 19 32 31 12 223 Table 6, continued Date 1950 Mean water tempera- ture Number Average measured length (inches) Number Average measured length (inches) Number Total not rneas. number taken June 1 63.0 4 17.9 2 19.0 • . • 6 2 63.0 • • « • • ♦ • • * . • 11 11 3 58,0 2 17.6 1 18 9 • • • 3 4 59.0 • • • • • • 0 • • . . 5 5 5 58.0 3 15.8 2 16. 8 ■ * • 5 June 1-5 • • • 9 17.1 5 18, ,1 16 30 6 65.0 • • • • • • 0 • • . « 8 8 7 63.0 9 16.4 2 17. 8 11 8 70.0 • • • • • * • • • • • 3 3 9 71.5 6 14.7 1 17 .3 • • • 7 10 71.0 • • • • » • * » • 7 7 June 6-10 • • • 15 15-7 3 17 6 18 36 11 64.0 5 16.3 • • • . • 5 12 62.0 • * • • • • • • • . • • • • 13 64. 5 18 16.0 8 16 .3 26 U 66.0 • ♦ • ... • • • . » * 3 3 15 65.5 14 15.8 4 16 .3 • • • 18 June 11- -15 • • » 37 16.0 12 16. .3 3 52 16 • * • • • • • • • • • • , t • 18 18 17 63.5 20 16.6 8 15 0 ... 28 18 57.0 • • • • • • • • * . , . 9 9 19 56.5 7 16.6 1 19 .0 8 20 60.0 • • • • • • • • • . . • • • June 16- -20 • • • 27 16.6 9 15 .5 27 63 21 61.0 1 18.2 • • • • 1 • 1 22 59.0 • • • * • • • • • • ► • • • a 23 60.5 • • • * • • • • • • ► • • ♦ • 24 65.0 * • • • • • • • • • • • • • 24 68.0 • • ♦ • • • • • 0 . . • • • June 21-25 « • o 1 18.2 • • • • ► • 1 26 68.0 • • • • • • • * • • ► • ■ • • 27 68.0 1 16.6 • • • • 1 • * • • « 1 28 64.0 • • » • • • • • • • » • • • • 29 64.O • • • • • • • . • • 1 • * • • T 39r 64.0 0*0 -T ' * ■ • • • • * • . * • June 26- -30 • • • 1 lb.b • • • * • 1 July 1-20 (Weir operations continuou*s - no lampreys taken) Totals and averages 506 16.4 162 16.9 493 1,161 18 Table 7. — Number and average length by_ sexes of samples of sea lampreys and tota 1 number of sea lanpre-'s taken in the Ocqueo c River, Pre sque Isle Couiaty'^ic] v«t ■ by_ dates and by p< jriods in 1950 Kales Fer aales Number no Number Average Number Average t Total Date measured length measured length measured nc . taken 1950 (inches) (inches) April 25- May 10 (Weir operation continuous - no lampreys taken) May 11 • • • • • • • • • ... • • • « • * 12 5 17.6 » » ■ ... • • • 5 13 17 18.3 4 18.7 • • • 21 14 9 18.9 6 18.4 • • • 15 15 • • • • « • • • • • • • 390 390 16 35 18.3 12 18.6 59 106 17 • • « • • • ♦ « • • • • 66 66 18 57 17.5 32 18.3 0 89 19 • • « • • • • * • ♦ • • 288 288 20 155 16.9 48 17.3 1,472 1,675 Hay 11- 21 20 278 ♦ • # 17.4 102 17.9 2,275 2,655 • • • • • • • • • 989 989 22 146 16.4 67 16.9 1,135 1,348 23 • » • • • • • • « • • • 377 377 24 154 16.4 53 16.5 781 988 25 • • • • • » • • • • • • 702 702 26 144 16.3 71 17.1 373 588 27 • • • • • • • • « • • • 380 380 28 106 17.0 41 17.4 • • « 147 29 • • • • « « • » ♦ .'. ♦ • « 541 541 30 145 16.0 68 16.7 399 612 31 • • • • • • ■ • • • • ♦ 755 755 May 21- 31 695 16. A 300 16.9 6,432 7,427 June 1 142 16.4 58 16.5 266 466 2 • • • • • • ♦ • * • • • 366 366 3 155 16.9 48 17.3 175 378 4 • • • • • ♦ • « • p • • 419 419 5 118 16.1 55 16.7 94 267 6 • • • • • • * « « • • « 319 319 7 154 16.5 61 16.9 137 402 8 • • • • • • • • • « • « 476 476 9 195 16.6 84 16.9 141 420 10 * • • 0 • o • • • • • • 499 499 dune 1- 10 764 16.5 306 16.8 2,942 4,012 Continued next page 19 Table 7, continued Males Females Number not Number Average Number Average Total Date measured length measured length measured no .taken 1950 (inches) (inches) June 11 172 16.1 76 16.8 193 441 12 • • ■ • • ♦ o • • • • • 348 348 13 138 16.0 65 16.9 • • • 203 14 * • • • ♦ • e • • • • • 231 231 15 117 16.3 64 16.7 30 211 16 o J 17.6 O 16.4 249 254 17 165 16. 4 57 16.6 76 298 IS • • • m • • 9 • • • • • 419 419 19 146 16.5 55 16.9 59 260 20 © • © • © © • * • • • o 297 297 June 11-20 741 16.3 319 16.8 1,902 2,962 21 165 16.5 60 17.0 85 310 22 • o • a • • • • • • • • 244 244 23 101 16.3 35 16.1 1 137 24 • • • a • 9 © • © • • • 163 163 25 31 16.2 12 17.0 51 94 26 26 15.8 9 16.7 11 46 27 105 15.7 46 16.0 • • • 151 28 30 16.2 13 16.9 46 89 29 58 16.3 26 16.1 1 85 30 32 16.1 12 15.8 34 73 July 1-10 June 21-30 548 16.2 213 16.5 636 1,397 July 1 43 15.4 27 15.9 70 2 51 15.5 17 16.6 68 3 13 14.9 5 18.6 18 4 • • • • • © • « « © • s 8 8 5 1 14.0 © • © • • © 1 6 1 14.9 2 15.6 3 7 15 14.5 10 16.0 25 8 16 14.9 5 15.9 21 9 17 15.4 5 16.0 22 10 5 16.5 2 15.4 7 162 15.3 73 16.3 243 11 4 13.7 3 16.5 12 1 16.8 1 15.7 13 1 14.6 1 15.8 14 5 15.6 • • • • 0 • 15 8 13.9 2 15.5 16 10 15.7 3 15.4 17 5 15.2 1 17.1 18 7 15.5 3 16.4 2 2 5 11 13 6 10 Continued on next page 20 Tablo 7 , continued Males Fema] .es Number Average ber Average Number not Total Date measured length measured length measured no. taken 1950 (inches) (inches ) July 19 5 15.1 > •4- 1Q O 9 20 2 14.* 4 •r 9 O ... 2 July 11- 20 48 15 cO IS 15.4 2 68 21 2 14.9 J 13.5 5 22 7 14,9 6 13.8 13 23 6 15*3 « 9 C * • • 6 24 4 14.9 1 15.0 ... 5 25 2 13 .7 • * * 9 9 9 2 26 2 15 oO • e • • 9) * 2 27 ■ • » 9 9 9 1 14.2 1 28 • • • * 9 9 • 99 • 9 O 9 9 * 9 9 9 2? • • • • • • • • 9 9 « 9 • 9 0 9 9 9 30 • • • • • 0 • • 9 • 9 9 9 9* 9 • 9 31 ♦ • 0 • • o • 99 • • 9 • • 9 • • 9 July 21-31 23 14.9 11 13.8 34 August 1 • • • « • • * 9 9 9 9 9 9 9 9) 9 9 9 2 1 16.1 a 9 i • 9 • 1 3 1 11.2 O • 9 • 9 9 1 4 5 14 9 4 I 12.5 6 5 1 18.3 1 13»2 2 6 • • » o 9 9 • 9 9 • • 9 9 9* 9 9 9 7 • • • • • ♦ 1 9.9 6 7 8 1 15.5 • « e • • 9 1 9 • * • • 9 » 1 15.5 1 10 1 16.0 9 9 9 9 9 9 1 August I'- ■10 10 U.9 L 12.8 6 20 ll ♦ • • • • • • 90 9 9 9 9 9 9 9 9© 12 1 13o0 "J 13.5 2 13 • • • 9 0© 9 9 9 9 9 9 9 9 9 9 9 9 14 • • • * * • 9 • 9 9 9 9 9 9 9 • 9 © 15 • • • • • • 0 9 9 • • 9 9 9 9 9 9 9 16 • • 0 • • © • • 9 • • • • • 9 9 9 « 17 9 • • a f ■ 9 9 9 9 9 9 9 9 9 9 9 9 IS • • • • • * 9 • 9 • . • 9 • 9 9 9 9 19 • • ■ • 9 © 9*9 9*9 • 9 9 9 9 9 20 • • • • • • • • > • • 9 • • 9 a « • Augu stll- 20 1 13.0 1 13.5 9 9 9 *C 21 • • 9 • • a 9 e « • 9 » • 99 9 9 S 22 9 9 9 • • • • • 9 9 9 9 9 9 9 9 9 * 23 9 9 9) • • • • 9 9 • • 9 9*9 999 24 • • • • • * 9*9 • * 9 9*9 999 25 • • 9 • • • * • • 9*9 9 9 9 9 9 4 26 • • • • • • 9 9 9 9*9 9*9 9*9 27 1 14 o 5 • « e 9 9 9 1 28 • • • • • » 9 9 9 • « 9 9*9 ■ 9 9 29 • O » » • • 9ft* 9 9 9 • 9 9 9 9 9 30 • * • • • • 1 14.5 1 AuguBtZL- 30 1 14.5 1 H.5 2 Tctals ar d A- /erases 3,271 16.4 1,343 16.8 14,203 18,822 21 and mean water temperatures and water gauge ture and1 wj nd and veath rr records for the 1 ocality: April 25 -Aug us t 30, 1950 Watei ■ temperature V iViean air Wind Date Min. Max. Water tempera- direction 1950 Mean Gauge 2/ ture and shift Weather Aoril 25 36 33.5 ul 15. U » E OvefcasT ' rain 26 38 38.5 39 15.0 - S ii ; cool 27 39 Uo.5 h2 16.5 - sw ti n 28 38 39. C Uo 16.1 - s n it 29 37 38.5 Uo 15.5 36.0 N n n 30 37 39.5 U2 i5.o 36.0 N it tt May 1 39 UO.O Ul 13.5 UO.O E it n 2 39 Uo.o Ul 13.0 36.5 W Clear fair 3 Uo 12.0 UU 13.0 U3.0 NE Overcast ; rain U Uo Uo.5 Ul 13.0 U3.0 N ti ; cool 5 1x2 U2.5 U3 13.0 U5.5 S tt ! warm 6 U3 U5-o U7 13.0 63.5 s it ; windy 7 uu UU.5 U5 1U.0 58.5 N Clear , cool 8 U3 U6.5 50 13. C U2.5 NE n it 9 U5 U7.5 50 12. U U3.0 S Overcast ; rain 10 U5 U7.5 50 12. U 51.0 SW n , cool 11 UU U7.5 51 12. U U3.5 s ti warm 12 U6 50.0 5U Guage 5U.0 WNW Clear ti 13 U8 52.0 56 Broken: 53.0 WNW Overcast, cool lU U9 52.5 56 Low 55.5 S n warm 15 52 55.0 58 Water 59.0 NW Clear n 16 52 55.0 58 n 53.5 N n n 17 U3 5o.5 58 tt U6.5 NE n ; mild 18 52 5U.0 56 it U0.5 NE Overcast, it 19 53 56.0 59 ii U6.5 NE Clear t warm 20 5U 59.0 6U it 5o.o NE n it 21 5U 59.0 6U n 52.5 E it it 22 59 62.0 65 it 61.5 NE Overcast ; cool 23 SS 59.5 6U tt 51.0 NE Clear ; warm 21 58 62.0 66 8.0 63.5 N Ovp.rcast i cool 25 6o 63.5 67 8.0 6U.0 SE n ; warm 26 58 62.5 67 7.6 62.5 NW it ; rain 27 61 62.5 6U 8.0 57.0 NW tt ; cool 28 58 61.0 6U Low 53.5 NW n ; warm 29 58 62..0 66 8.0 57.0 NE Clear it 30 58 63.0 68 7.5 5U.5 SE Overcast n 31 61 6U.5 68 7.5 61.5 W it it June 1 62 65.0 68 8.0 59.5 S Clear ; warm 2 62 65.0 68 Low 58.0 s ii . it 3 58 61.0 6U 8.0 52.0 N it ; cool U 57 62.5 68 7.5 51.5 W it ■ it 5 58 63.0 68 7.2 57.5 None Overcast • ti 6 62 6U.0 66 7.2 67.0 SW-N n , warm Continued on next page 22 Table 8, continued Date Watei ■ temperature l/~ Mean air Wind 1950 Min. Max„ Water tempera- directio n Mean guage 2/ ture and shift Weather June 7 62 6Ii.o ~T6™ 7.0 66,0 SW Clear 3 warm 8 62 67.0 72 6.7 7U.0 SW 11 J hot 9 66 69.5 73 7.5 76.0 SW Overcast 1 tt 10 68 71.0 Ik 7.3 59.0 W I! 3 cool 11 60 66.0 72 7.5 56.0 N Clear } warm 12 60 61.0 62 6.5 56.0 E ti 3 it 13 63 68.5 7U 6.0 55.0 NW ti 5 1! 111 66 70.5 75 6.0 62.0 MW Overcast 5 II 15 66 70o0 Ik 6.1 67.0 E ^lear } I) 16 68 71.0 7U 6.5 6iu0 NW Overcast > cool 17 51 56.5 62 6.0 62.0 NE Clear > fair 18 6o 6U.5 69 6.0 U9.0 SW Overcast i cool 19 60 6u,0 68 6.0 53.0 W 11 9 ti 20 62 65.0 68 6.1i 6U.5 SW it > warm 21 6o 65.0 70 6.0 58.0 w Partly " l cool 22 60 6U.0 68 5.8 51i.o E Overcast j rain 23 62 66.0 70 5.5 67.5 SW tt 1 warm 2k 66 69.O 72 6.7 7U.5 W Partly " 1 11 25 68 73.0 78 6.0 71.0 NW Clear ) it 26 68 73.0 78 7.0 71.5 SW Clear » 11 27 6U 71.0 78 6.5 67.5 w Overcast cool 28 6I4 68.0 72 6.5 62.5 SW n 0 warm 29 6i* 68.0 72 6.5 71.0 w •-lear » cool 30 61; 69.O Ik 6.5 61. 0 SW Partly overcast 3 cool July 1 68 70.0 72 6.5 56.0 SW Clear 1 fair 2 62 66.0 70 6S 67.0 SW Overcast 3 warm 3 63 65.5 68 6.0 58.0 N Clear 3 fair h 62 66.0 70 5.6 61.0 E Overcast i cool 61 65.5 70 6.0 59.0 w Partly « 3 warm 6 62 66.0 70 6.5 " 60.0 w Overcast 3 tt 7 62 68.0 Ik 6.0 65.0 w Clear J 11 8 63 6U.5 66 6.0 67.0 None ti 3 hot 9 66 71.0 76 6.0 67.5 11 11 3 warm 10 68 73.0 78 6.0 75.0 11 tt 3 tt 11 68 69.O 70 6.0 71.0 11 11 3 11 12 70 75.0 80 6.0 72.0 in it 3 tt 13 52 65.0 78 6.1} 72.0 W Overcast 3 cool m 63 68.0 73 8.0 52.5 w it 3 II 15 61 6U.5 68 6.5 62.0 SW Clear 9 warm 16 66 72.0 78 6.5 73.0 s Partly overcast 1 warm 17 66 71.0 76 7.0 73.5 None 11 it •j warm 18 68 71.0 Ik l.k 67.0 NW Clear 3 cool 19 66 71.0 76 7.0 66.0 E Overcast 3 11 20 62 65.0 68 6.0 59.0 NW Partly " f warm Continued next page 23 Table 8, continued Date Water temperatures l/~ Mean air 19$0 jMin Max " Water temperatures Wind direct- ion and shift Mean gauge 2/ Weather July 21 66 71.0 76 7.5 59.0 W Part, overc \ wan 22 66 71.0 76 7.5 70.0 NW it 11 23 66 72.0 78 6.0 68.0 S Clear it 2b 68 71.0 7b 5.5 70.0 w Ovecc 11 25 68 70.0 72 9.0 66.0 w Clear \ fai 26 66 71.0 76 7.5 66.0 sw " overc ; war 27 66 72.0 78 7.5 67.O s n 11 it 28 72.0 8.0 76.0 None Clear it 29 70 7b. 0 78 8.0 71.0 t! Overc 11 30 70 7U.0 78 7.3 72.0 sw it ; rai 31 68 70.0 72 7.0 65.0 None it ; wan Uigust 1 66 68.0 70 9.0 61.0 NE 11 ; rai 2 62 65.0 68 8.0 58.0 NE 11 » fog 3 62 65.0 68 9.0 56.0 - it it 1» 60 63.0 66 9.0 58.0 NW 11 11 ; coo 5 60 6U.0 68 8.5 6I.0 W Clear ; wan 6 62 67.0 72 8.0 6b. 0 SE it it 7 62 67.0 72 8.5 63.O SE it n 8 6b 69.O 7b 8.5 68.0 SW " Overc 11 9 66 70.0 7b 10.0 72.0 SW n 11 n 10 66 70.0 714 8.5 68.0 NW n ti ; coo 11 62 68.0 7b 9.5 63.O N Clear it 12 62 68.0 7b 8.5 58.0 NW ti j wan 13 62 68.0 7b 7.5 56.0 None it it lb 6U 69.0 71* 7.0 63.0 SW n, 11 15 6b 69.0 7b 7.5 69.0 S Overc n 16 6b 69.O 7b 7.3 70.0 W 1! It ; coo 17 68 71.0 7b 7.5 69.O S " overc ; wan 18 6b 69.O 7b 9.0 63.0 NE Clear J coo 19 5b 63.0 72 8.5 52.0 SW " overc . n 20 62 66.0 70 12.0 56.0 NW it n • 11 21 60 65.0 70 10.3 66.0 SE tt » 11 22 68 69.O 70 8.0 52.0 None Clear . it 23 58 63.0 68 8.0 53.0 S Overc 11 2b 62 63.O 6b 8.0 59.0 SE n ti it 25 60 65.0 70 8.0 69.0 N n 11 26 58 63.O 68 7.0 60.0 N 11 11 27 60 61u0 68 7.0 59.0 None 11 ; rai 28 62 6b. 0 66 8.5 58.0 11 n . it 29 60 62.0 6b 9.5 56.0 NE it 11 30 58 60.O 62 9.5 U9.0 NE 11 ; coo 1/ Vfeter-temperature station at weir 2/ Water-gauge readings are absolute depths in inches across the deck of the weir 2b The migration was almost exclusively a nocturnal one, with the exceptions appearing very late in the season and only in the larger of the two streams. Variations in time and character of migration in different streams of differing characteristics in the same zone . — The runs in the following five streams of diverse character in Control Zone H-l were selected for comparison: Ocqueoc and Trout uivers and Green, Milligan, and Grace Harbor Creeks (Pig. 6). Essentially, all runs in a limited area such as this, regardless of the sire of the stream entered, begin on about the same date. The first migrants entered traps in these streams on the following dates: Ocqueoc River — May 12; Trout River — *%y 3; Green Creek — April 2$; Milligan Creek — May 6; Grace "Harbor Creek — May 9. The lateness of the first capture in the Ocqueoc River is not normal for that river and is attributable to the blocking action of the right-angle- type weir installed in the stream (see Applegate, 195>0) . The early captures in Green Creek were due to the location of the weir which was practically on the Lake Huron beach. Earlier researches demonstrated that lampreys explore the mouths of stre-ms for many nights orior to upstream movement until stream temper- atures attain a satisfactory level for migration. Such exploring indi- viduals evidently were captured in this trap. The weirs in the other four streams are located seme distance upstream. Although water temperature is the greatest governing factor in determining when and in what numbers upstream movement will occur, the general character (Continuity) and duration of the runs can be strongly influenced by the size of the stream and the stability of its volume of flow. The Ocqueoc River, a moderately large stream with the most stable volume of flow from season to season, has the most prolonged and consistent run in the area. In 1950, this run continued until August 30 (irig.6). Green Creek, small, but with a stable volume of flow throughout the year, attracted scattered migrants until August 15 but in far less numbers than the Ocqueoc River. During the period of major movement, the run in Green Creek increases and decreases ab- ruptly as in the other smaller streams of the area in quick response to climatic changes. The Trout River and Milligan Creek, small streams with severe daily and seasonal changes in flow, tend to decline to a trickle by the end of June. This change is reflected in the sea lamprey runs which cease at that time. Carp Creek, mentioned in previous sections, falls in this category (Table 6). Very small tributaries, 2 to k feet wide, attract occasional mi- grants where the flow of the stream crosses the lake beach in a narrow concentrated channel. Crace Harbor Creek was typical of this type. In another small tributary in the area, Cedar Creek, the discharge was dispersed across the beach zone in a broad, shallow sheet. No lampreys 25 / w. v\ GRACE HARBOR CREEK PRESQUE ISLE CO, MICHIGAN ^luj.ll.uxu1i uj i ^fr^L^ ^ ^^ " I IAJ ^ ' Lftu" w ' ' ' ' ' ' ' ' ' ' ' ^ '■'■" " " ' i uj ***>!. ™_ " *' J ^ " !» » » ' * » 'J /K .1 1: H I i i I i 1 I i I i n-[ft i i i i i i i i ' i U/^....U,.A. . MIL L/C AN CREEK PRESQUE ISLE CO.. MICHIGAN *e li 30 1 1 ' n in 1 1 1 n n it , i 1 1 1 1 1 1 1 , i i i n i GREEN CREEK CHEBOYGAN CO., MICHIGAN iiliUmttiHiwiiiiiiiiiiiuiiAiiiiiiii , ,, TROUT RIVER PRESQUE ISLE CO., MICHIGAN ■UJ I II UJ I M I I I II I I I I I I I I I I n in, v ■ — A; OCQUEOC RIVER PRESQUE ISLE CO, MICHIGAN II IMIIIM IIIIIIIIMHrflMil nun n II M lllliiillMi hi mi ii ii iiiVmtmuatm^^uu ii tn. i,, i ■ ii miiil *igure 6. --Number of sea lampreys taken each day during 1950 season In five northern Lake Huron tributaries of different size and character, and mean stream water temperatures for period. entered this creek. Runs in these small tributaries are erratic and tend to cease early; that in Grace Harbor Creek ended on June 21. Variations in the time of migration in di f f erent areas (latitudes) of the same lake and in different lakes. — It may be remarked here, in passing, that the opening of the 1950 season on northern Lake Huron was the latest in four years. The first sea lamprey did not enter Carp Creek in Presque Isle County, Michigan, until May 3. During four years of widely differing climatic conditions, sea lamprey runs in this creek have commenced as early as April 9 (I9u9), April Ik (19^8), and April 22 (19u7). Observations indicated that conditions were similarly late in 19$0 throughout the entire upper Great Lakes area. *ive streams in widely separated areas of Lakes Michigan and Superior in which weirs were operated in 1950 were specifically se- lected for this study (^ig.?). These streams from south to iorth weres Trail Creek, near Michigan City, Indiana; Hibbard's Creek, Door County, Wisconsin; Carp Lake River, Emmet County, Michigan; Black River, Mackinaw County, Michigan (all tributary to Lake Michigan); and Pendill's Creek, Chippewa County, Michigan (tributary to Lake Superior). Complete runs were not captured in two of these five streams but where complete data were lacking, extrapolations were made, based on past studies of spawning runs. Examinations of these data reveals that the peak of upstream movement is progressively later in each stream from south to north (Eig.7). In 1950, the run in the stream tributary to the southern tip of Lake Michigan (Trail Creek) reached its peak about 3 weeks earlier than that entering a tributary of the more central area of the lake (Fibbard Creek), and was about k weeks earlier than those entering flowages tributary to the lake ' s northern tip (Carp Lake River and the Black River). Runs in streams in comparable latitudes in Lake Huron attain their peak of migration at the same time as those in Lake Michigan (Fig . 6; Tables 6 and 7). The small run captured in Pendill's Creek, tributary to the eastern extension of Lake Superior, suggests that the major upstream movement in streams of this area occurs as late as or later than that which takes place in streams tributary to the northern- most reaches of Lake Michigan. Data collected in 19^0 demonstrated that the Pendill's Creek run did not even commence until 3 1/2 weeks after migrants first appeared in streams of the Mackinaw Straits area (northernmost extensions of Lakes Huron and Michigan) . No point is made of actual, calendar dates in conjunction with the beginning and peak of sea lamprey migrations. Past studies have indicated that such dates are highly unreliable, since they vary from year to year with climatic conditions. It is sufficient to know the differences in time of migration between different latitudes of one lake and among the different lakes so that operations for control of the species may be properly scheduled. 27 3 ^ < x eo- = S !, » - 3S.- 10 - PENDILLS CREEK 20 CHIPPEWA CO, MICHIGAN 10 5 i nni in 25 101 5 1PR1L 10 IS 20 25 JO 1 1 10 I) 20 21 301 i 10 IS 20 21 30 1 5 10 IS 20 2S l' HAT JVNI JULY AUGUST 5. l« ■^ JO: a- .100 K != £ Ml I 'o- 3*> S ^ MO 5 5»- 5c no 210 J 240 q_ ^,«o- i _ji;o - ^ o ~J 80 - x "r- ki <0 20 - ' ' ' ' ut ill I iUi 1 1 iWj-iLrTM I I BLACK RIVER MACKINAW CO, MICHIGAN Vim \++W\ i V»-MvrTr»^4si 1 1 1 .ui Jim i^-i i " ' ' U. 2S 301 5 10 II 20 2S 30 I S 10 15 20 25 101 1 10 II 20 21 30 I 5 » 15 20 21 21 301 1 Figure 7 -"Number of sea lampreys taicen each day during 19?0 season In five streams in different geographic latitudes, with mean stream water temperatures for period. Movement and dispersion of a blocked spawning run of sea lampreys. In several large Great Lakes watersheds sea lamprey spawning runs are blocked near the mouth of the main stream by power dams. An example of such a watershed is that of the Cheboygan River flowing into the north- west tip of Lake Huron in Control Zone H-l (Figs. 2 and 8). To determine whether or not it is worthwhile to trap and destroy these large runs which are prevented by barriers from reaching suitable spawning grounds , a tagging experiment was conducted in that river during the spring spawning migration of 1°$0. Conditions were favorable for such an ex- periment as the weirs and traps operated within the control zone pro- vided extensive facilities for the recapture of marked lampreys. Field experiments, anatomical studies, and other observations seemed to indicate that many of these blocked individuals do not locate suitable streams in which to spawn and ultimately die in the lake proper without spawning. The tagging experiment was conducted to find the answers to the following questions. (1) What proportion of a blocked run is diverted to other streams along the shoreline and what proportion disappears back into the lakes presumably to die without spawning? (2) In what directions do blocked migrants travel, how far and how fast do they travel, and in what numbers do they enter other watersheds in relation to distance from the blocked stream? (3) Do these diverted migrants make a significant contribution to the spawning runs in other streams? A total of 2,8U3 adult lampreys were trapped below the paper mill power dam in the Cheboygan River and tagged during the period May 7 to June 10, 195>0. Of this number, 289 or 10.2 percent were recovered. Of the lampreys recaptured, 25u were trapped in the sea lampreys weirs in the streams of Control Zone H-l, 3U specimens were returned through the cooperation of commercial fishermen who captured them in trap nets and gill nets set for other fishes, and the remainder were captured in a stream on the eastern tip of the Upper Peninsula (Figs. 10 and 11 j Table 9). Forty-two lampreys taken had obviously been tagged but the tag had been torn out. A ragged, "V-shaped" scar was observed in the area where the tag had been placed. These lampreys were counted as tag recoveries in analysing the data, except in those calculations involving the number of days between tagging and recapture. A few dead, marked lampreys were recovered from the Cheboygan River, most of them hanging by the tag. from steel wire tangles (city refuse) on the river bottom. These were not counted in the total number tagged or as recoveries. From observations at time of tagging it is known that a few tagged 29 Table 9.— Location of point of recovery of marked sea lampreys and distance from point o f tagging (W ith number recovered, percentage of total tags re- covered, percentage of total tagged, and days out ) distance Percentage Location from point of total of tagging Taga recovered tagged Days Out (miles) Number Percentage MTHI mum - Mean Maxi- mum Control Zone H-l: In streams: Little Black River 2 55 19.0 1.93 2 10.7 30 Elliott Creek 3 18 6.2 0.63 2 10.3 26 Martin Creek 8 3 1.0 0.11 28 29.7 31 Green Creek 12 89 30.7 3.13 3 1U.2 65 Milligan Creek 15 3 i.o 0.11 6 7.7 11 Grace Harbor Creek 23 1 o.U 0.0U 11 11.0 11 Carp Creek 25 7 2.U 0.25 6 9.2 12 Carp Lake ftiver 25 5 1.7 0.18 8 1U.0 18 Ocqueoc ^ver 30 71 2U.5 2.50 U 1U.8 37 Trout River U3 2 0.7 0.07 13 15.5 18 Total in streams • • ■ 25U 87.6 8.95 • * • • • • • • • In the lake: West of Cheboygan 2-5 17 S.9 0.60 2 15.5 U2 Lighthouse Point 3 1 O.U o.oU 15 l5.o 15 Poes Reef 5 2 0.7 0.07 27 38.5 50 Bois Blanc Island 5-10 5 1.7 0.18 11 25.U 35 *'ly Point 15 l O.U o.oU 1U lU.o 1U Mackinaw °ity 17 2 0.7 0.07 6 10.7 lU Round Island 17 1 o.U o.oU 31 31.0 31 Cecil Bay 23 1 o.U o.oU 12 12.0 12 Total in lake • • • 30 10.6 1.00 • • • • • • • • • Total in Control Zone H-l • • • 28U 98.2 10.03 • • • • • • • • • Other Areas t In streams: Mackinaw Creek 25 1 O.U o.oU (6 to 19 days) (Hessel, Mich.) In the lake: St. Martins Bay 25 3 1.0 0.11 7 12.0 2L (Lake Huron) Glen Arbor Bay 150 1 o.U o.oU • • • 52 • • • (Lake Michigan) Total in other areas • • • 5 1.8 0.19 • • • • • • • • • Grand Total • * ♦ 289 100.0 10.22 2 • • • 65 30 Figure 8.— Power dam in Cheboygan River at Cheboygan, Michigan. Figure 9» Peterson- type tag applied to migrant sea lamprey. 3 1 SCALE Of MILES POINT Of TAGGING ^- TAGGED LAMPREfS HLCOVERE IN STREAMS — TAGGED LAUPBEY5 RECOVERED IN THE LAKE BASE MAP OFFICIAL MICH STATE H'tAT MOP FOR I9SO ^lgure. — 10. --Small-scale chart of upper Great ^akee showing general dispersion of marked lampreys from blockaded spawning run. lampreys escaped upstream through the power dam boat locks into the Mullett Lake — #urt Lake drainage. Specimens for tagging we^e obtained by dipnetting at night below the paper mill power dam on the Cheboygan River. Sea lampreys collected early in one night were held in live boxes overnight and tagged the following morning. Originally a special experimental trapnet was ooerated but it proved to be inefficient because of improper mesh-size^ strong cu rents, and the accumulation of large amounts of detritus on the webbing. Two types of tags were used in the experiment. The first groups of the lampreys (1,585 individuals) were tagged with numbered Peterson- type tags, three-eights of an inch in diameter. One disc was red and the other was white. These were applied with 1 3/u nickel wire pins through the dorsal musculature just anterior to the first dorsal fin (Fig, 9). The remainder of the lampreys (1,258 individuals) were marked with numbered jaw tags of fingerling size. The jaw tags were clamped through the anterior portion of the first dorsal fin just above its juncture with the back. Prior to tagging, the lampreys were anesthetized with a 5-percent solution of urethane. Anesthetized lampreys were measured, tagged, and held in a live box until they had recovered fully. They were then released. No lampreys so handled were held in excess of 2 hours. **ny individuals not appearing fully recovered in this time were destroyed to exclude them from the experiment. There was evidently a difference in the efficiency of the two types of tags used, Of the 2l\l tags recovered, only 7k were jaw-type tags, ^t was noted that lampreys taken in commercial gear were almost always cap- tured when the Peterson-type tag became entangled in the mesh. The jaw tag could not similarly ensnare the lamprey. If the 3k Peterson- type tags recovered in the commercial fishery are disregarded, the jaw tags still made up only 35 percent of the tags recovered although kk percent of the lampreys were marked with this type of tag. The difference in efficiency still evident in the figures after this adjustment is probably attributable to difficulty in detecting the small tags under night work- ing conditions at the weirs. The large red and white disc tags were highly visible even in subdued light. The recovery of 2[Sk marked lampreys in the weirs and traps of Con- trol &one H-l indicates that at least 9 percent of the blocked Cheboygan River run was diverted to other streams within the zone in both direct- ions along the shoreline. The Cheboygan River sea lamprey run was conservatively estimated by experienced observers at U0,000 migrant individuals. On the basis of this estimate, the total number tagged, and the percentage recovery of tags, it appears that about 3,600 of the spawning run -ea lampreys captured in the streams of the control zone were diverted Cheboygan River migrants. By the same token, 91 percent or an estimated 36, uOO sea lampreys from the blocked run were diverted into streams outside the control area or wandered aimlessly in the lakes, presumably to die without spawning. 31 Several tagged lampreys were taken by commercial fisherman in the Straits of Mackinaw, St. Martins Bay, and Mackinaw Creek near Hessel, Michigan. These recoveries indicate that many of the Cheboygan River migrants find their way across the deeper waters of the Straits and into the streams and rivers of the Upper Peninsula of the Michigan and perhaps contribute significantly to the spawning runs of those streams. The portion of the blocked run that is diverted into other streams apparently moves in all directions from the mouth of the Cheboygan River with the majority following the Lake Huron and Lake Michigan shorelines of the lower peninsula (Figs. 10 and 11). It is difficult to define the farthest limits of dispersion of the blockaded Cheboygan River run as there were few devices for recapturing the tagged speci- mens in any area other than Control Zone H-l. Since little publicity concerning the experiment was given beyond the local area, it is en- tirely possible that some tags recovered by commercial fishermen in more distant locales were not returned. It is significant, however, that no tagged lampreys were taken in the Pendill's Creek weir and trap (Chippewa Co.), the Black River weir and trap (Mackinaw Co.)* the Trail Creek trap (La Porte Co., Indiana), any of the 7 installations operated in Wisconsin, or those operated by the Province of Ontario. The most distant reported recovery was from Glen Arbor Bay, Lake Michigan, approximately 150 miles west and south of Cheboygan (Fig. 10). This lamprey was taken by a commerical fisherman in a gill net 52 days after it was tagged and released at the power dam. In the other direct- ion the farthest recoveries were two lampreys taken in the trap in Trout River, Presque Isle ^o., U3 miles east of the point of tagging (^ig.ll). The first capture was recorded 13 days after release and the second 5 days later. Evidently little correlation exists between distance traveled and the number of days elapsing between tagging and recapture within the limited area where devices were present for recovering the migrants. The number of days from the time the lampreys were tagged until they were recovered varied greatly (Table 9). Within a radius of 2 to 10 miles of the point of tagging, total time out varied from 2 to 50 days; 11 to 20 miles distant it varied from 3 to 65 days; and 21 to U3 miles away it varied from U to 37 days. Obviously some of the tagged lampreys wandered in the Lakes for a considerable time before entering another stream in search of a spawning area. Others apparently did not deviate from the most direct route to the stream they entered. The influence of the diverted Cheboygan River run on the runs of other streams varied with the size of the stream and the distance from the Cheboj^gan River. For examole, the Ocqueoc River which is the largest unobstructed stream in Control ^one H-l, is 30 miles east and south of the point of tagging ; 71 tagged lampreys were trapped there. 35 Green Creek, 12 miles east of Cheboygan is only about one tenth the size of the Ocqueoc River and yet 89 tagged lampreys were captured in this stream. In two even smaller streams, Elliott Creek (3 miles dis- tant) and Little Black River ( 2 miles distant) 18 ana 55 tagged spec- imans respectively were recovered (Table 9) • Significant contributions by the blocked Cheboygan River run were made to other runs in streams UO miles distant alongshore in one direct- ion and 25 miles in the other. The proportion of lampreys among the runs of several streams studied that had their origin in the Cheboygan River varied inversely with distance from that blockaded stream (Table 10). For instance, the Little Black River, 2 miles west of Cheboygan, had a run of 953 lampreys. On the basis of the aforementioned estimate of ii0,000 lampreys as the size of the blocked Cheboygan River run, the 55 tagged lampreys recovered in this stream would indicate that 772 specimens or 8l percent of the total catch were diverted lampreys. From similar computation it is found that in the Carp Lake River, 25 miles west of Cheboygan, 2 percent or 76 of the 3,821 individuals taken there were from the Cheboygan River run. In an easterly direct- ion, 95 percent or an estimated 253 of the lampreys taken in Elliott Creek (3 miles distant) were diverted migrants. It is further indicated that of the run in Green Creek, 12 miles east, 6I4 percent were origin- ally from the same river. The Ocqueoc River, 30 miles east, attracted an estimated 1,000 individuals from the diverted run. This figure was only 5.3 percent of the total Ocqueoc River run. The two tagged lam- preys caught in the Trout River weir and trap, h3 miles distant, indi- cated that 1.6 percent or a probable 28 individuals had originally en- tered the Cheboygan River. It is apparent from the results of this tagging experiment that a significant portion of such a blocked run is diverted to other streams in the immediate area which have accessible spawning grounds. Signif- icant contributions by this blocked run were made to spawning runs in streams 1|0 miles distant alongshore in one direction and 25 miles distant in the other. It was also of interest to note that some sea lampreys swam offshore, rather than following the shoreline in their search for a spawning stream, crossed the Straits of Mackinaw, and appeared off the shoreline and in streams of the Upper Peninsula of Michigan. It may be concluded from this experiment that trapping operations to "siphon off" these large blocked runs may be of considerable bene- ficial effect. Against such actions is the observation in Control Zone H-l that these blocked and diverted migrants appearing in other streams contributed only a portion to an already existing surplus of lampreys entering these streams for which no spawning facilities were available. 36 Table 10. -"Probable contribution of the biockei arri diverted Cheboygan River sea lamprey run to rims ±n other near- oy streams with accessible spawning grounds. Distance from Total number Probable proportion of Stream Cheyboygan River of lampreys run that were diverted (miles) entering stream!/ migrants from Cheyboygan River 953 266 l,9U5 700 1,161 3,821 18,882 1, 702 Little Black River 2 Elliot's Creek 3 Green Creek 12 Lgan Creek 15 Carp Creek 25 Carp Lake River 25 ueoc River 30 Trout River U3 1/ Number taken in weir and trap Number Percentage 772 81.0 253 95.0 1,252 62*. 0 U2 6.0 98 8.J4 76 2.0 1,000 5.3 28 1,6 37 Evaluation of various types of mechanical control devices 5/ In the following paragraphs the various types of devices for the control of sea lampreys mentioned frequently in this and earlier re- ports are evaluated as an aid in the planning of sea lamprey control programs o x'ive types of devices have been refined to a point where they may be considered effective, if somewhat expensive, control mechanisms o (l) Permanent- type weirs and traps similar to that installed in the Ocqueoc River for capturing spawning runs (Figure 12) « Although the Ocqueoc River weir and traps, as installed, were functionally satisfactory, their structural characteristics were not„ Designs have been tentatively worked out for a permanent- type sea lamprey weir which will be a vast improvement over the Ocqueoc weir in stability and ease of operation . Construction materials are reinforced concrete and steel throughout,, This type of structure can be placed in streams of moderately large size and of almost any width orovided it can be so installed th^t not more than 5 feet of water will pass across the deck of the weir during flood stages. This limitation on depth is necessary because of the very narrow spacing required in the grates (racks) or screens of a sea lamprey weir; any aperature or spacing wider than l/2-inch will permit the upstream escapement of smaller individuals. It is almost impossible during floods to keep the grates of such a weir cleared of water-borne trash by manual means where the water depth is greater than 5 feet„ Presently designed structures will handle up to 2,500 cubic feet per secondj larger volumes can undoubtedly be handled with proper designing. Permanent-type structures of suitable design can be installed at an average unit cost of $222.00 per linear foot of structure, exclusive of engineering and construction-supervision costs. This figure is based on engineering estimates prepared for a typical group of larger northern Michigan streams. It is not recommended that these structures be built at right angles to the direction of stream flow (shortest distance across stream). No economy can be attained in a long-term program of operation by such construction. The impounding action of the structure creates serious erosion 5/ These devices are distinguished from electrical (electronic)^ chemical^, and biological control devices or- techniques which are currently under investigation. 38 Figure 12 . — Permanent- type sea lamprey weir end trap in Ocqueoc River, Presque Isle Co. , Mich. Figure 13. — Dam and inclined-screen sea lamprey trap in Carp Lake River, Emmet Co., Mich. 39 problems in the loose soils characteristic of the Lake States area which require 3ontinual and expensive attention. These problems can be alleviated to a great extent by constructing such weirs diagonally across the stream or in a "V" plan. The increased area for passing water thus produced decreases the impounding action of the weir to a minimumjscouring and erosion are likewise brought to a minimum. (2) and (3) Portable- type weirs and traps of the Carp Creek and Milligan Creek styles for medium-and small-size streams respectively, for cap- turing spawning runs (Figs. 3-5, Ik and 15). Carp Creek style portable weirs and traps can be installed and operated effectively in streams up to 00 feet wide if maximum flood levels passing through the screens do not exceed 30 inches in depth, and if careful maintenance is accorded the weirs during flood periods. The maximum volume of flow which these weirs can probably handle is about 300 cubic feet per second. Where greater volumes of water must be passed, permanent-type structures are recommended. These weirs, constructed of lumber, l/2-inch-mesh hardware cloth and steel fence posts, are perhaps the most economical control device which has been developed to date (Figs, llj and 15). They may be prefabricated and installed for a unit cost of $26.00 per linear foot of stream width exclusive of engineering and construction- supervision costs. This unit cost is based on a "V'-plan structure with the wings of the weir set at a 32° angle to the bank. The term "portable" weir is derived from the fact that after each spawning run season, all of the structure except the sills, up-right posts, and abutments is removed from the stream and stored until the next season, Where experience gained from one or more years of operation has shown that a portable-type weir can be operated effectively in a given stream, an inexpensive weir substructure and abutments of concrete can be installed. Portable-type weirs can be reinstalled repeatedly and operated with increased ease and with maximum effectiveness for many years upon such a stable base. The Carp Creek stye is impractical in most streams less than 10 feet wide. The Milligan Creek style weir was developed for these smaller tributaries, 10 feet or less in width, in which maximum flood levels passing through the screens do not exceed 2li inches (Figs. 3 and 15). Uo 4 i z * S O I- E < w UJ O Syp U. > W o tr lu H UJ > 2UJ. ;?" a. < rr I- Q£ ft. . — UJ 5a cr< UlUJ Zuj £Oa u „ uiS Q.LU 21 2=> . t/> — cr uj o ^J > >- ^ — ZUJV o. < cc h- Z£ UJ O 5 u- >=? o^ Un «* or uj 3= -1 tt-s u. < 2? LiJ < o _i < UJ in what diminutive weir and trap can be built and installed in a 1G- foot-wide stream Tor less than -$50.00. If a greater volume of water must be handled than is indicated above or if the volume of flow is estimated at greater than IiO cubic feet per second, it is recommended that the stream bed and banks be so altered as to permit the installation of a Carp Greek style structure. These nortable weirs, if properly installed, are amazingly sturdy and will give many years of service. The prototype of this weir in Carp Creek, Presque Isle Co., Michigan, has been used for four consecutive year1: and will serve for many more before the replacement of any of its parts is necessary, However, the limitations of the device should not be overlooked and where any doubt exists as to its ability to handle spring floods, only a permanent-type weir should be considered. (h) Dam and inclined-screen trap units of the Carp Lake River type for capturing young downstream migrants (Figs. 13 and 16) . This device is extremely effective in capturing all of the youngs recently transformed sea lampreys which are moving down- stream to begin their parasitic existence in the lakes. It can be installed, however, only in streams in which it is practical to construct a dam. The flat topography of the land and the generally low gradients of the streams of the Lake States thus place a limit- ation on the use of this device. At least a 5-foot head must be created by the dam in order that the tailwater will not interfere with the installation or operation of the trapping screens. It is frequently difficult, at least in Michigan drainages, to find a satisfactory site in the lower water-course where a dam creating such a head can be built, Generally speaking, the use of the dam and inclined-screen trap is probably limited to those streams that are less than 75 feet vd.de and in which only mild, or at. worst moderate, spring floods occur. The pilot model of this type of structure was installed and developed in the Carp Lake River, Emmet Co,, Michigan, by the Michigan Department of Conservation at an aggregate cost of approximately £6,000.00, Although the Carp Lake River was originally only 33 feet wide (at mean level) at the ooint of construction, a 90-foot, double- i.'all dam was required because of the porosity of the surrounding soils. Installation cost will, therefore, vary widely with stream and soil ditions and resulting construction requirements. (h) Barrier dams for diverting spawning runs of sea lampreys such as that installed in the Black River, Mackinaw Co., Michigan (Fig. 17). 1*3 EXPERIMENTAL BARRIER DAM (SEA LAMPREV BARRIER) BLACK RIVER, MACKINAC COUNTY OlAGRAUATiC PLANS v c »■-■'..-.*; .■ .. i - " ^y / 1 »BUTU€MT IT." .'■■',■■ ■>"■■, ■ '■■■T-v:: ■t twM Powi.^-t-a^oei anon. I "*» J •WON i»t«l t»* *>t ww} X"~T~" *mv' ■:"T""" r—.,"r V',"" :;-—"-:—'—",— : f "j:;":v;;J ■J W ! ' & VtUT O-T . :'■.".,:.'■? .1 ! SECTION rx. FRONT ■i } ,. SLOTS Mlltll 1 •]1 1 i 1 1 i -<■■+■ — ..- -i- — «• — jTOLUjirEimK"', n.*T pncmioms • DETAIL OF STEEL LIP Figure 17. — Diagrammatic plans of a sea- lamprey barrier dam(ueinforcing details not shown). This device, when properly adjusted, is self-operating and prevents the upstream migration of sea lampreys to their spawning grounds while permitting the escapement upstream of most migrating food and game fishes. It is desirable that barrier dams be used singly or in groups in conjunction with weirs and traps in adjacent or nearby streams.. Thus, diverted migrants may be trapped in other streams along with the runs initially entering them» Used in this manner, the barrier dam, an essentially self -operating device, may serve as an aid in reducing the operating costs of a control program based primarily on weirs and traps. All of the limitations with which the dam and inclined- screen device was burdened apply to the barreir dam. At least a k foot head must be created for proper functioning of the special curved lip applied to the dam wall or spillway. In all respects the problems confronting the installation of both the barrier dam and the dam and inclined=screen trap are similar and cd nstruction costs of both devices will be approximately „ the same. The experimental barrier dam built by the Michigan Department of Conservation cost about $3,500,00 for a wooden- type structure in a stream 25 feet wide. Construction of these dams of wood is deemed inadvisable. If a sounder and more permanent structure were built of reinforced concrete, the cost would be about doubled in a stream of this size (Fig. 17) ■ The preceding structured, if properly maintained and given regular attention will capture or block entire upstream or downstream runs. This 100-percent efficiency of operation is absolutely essential. In view of the known natural history of the sea lamprey it appears biologically unsound to effect any- thing less than the entire destruction of a run into a stream if control of the species is to be accomplished. This total destruction requires continual attendance upon the weirs by trained personnel to keep the racks or screens cleaned, to prevent over-topping, and to check the structure for breaks or failures,, SUch continual attendance is expensive. Weirs of the Fish and Wildlife Service are cleaned and cheeked at least every 8 hours during spring high-water levels. Day and night crews are required. Costs for proper weir operation are therefore high. Since construction costs of the preceding mechanical control devices are not excessive (and for the portable-type weirs and traps may be considered very low), one dangerous pitfall in effecting a sea lamprey control program based on these devices must be avoided]; that is, of judging the cost of the program in terms of the initial cost of installing the structures U6 and dismissing their annual operation as a minor maintenance problem. As a measure of the relationship between initial cost and annual operating costs, an example may be cited. A plan has been prepared for the installation ;.nd operation of 15 ad- ditional weirs and traps in streams tributary to Lakes Huron and Michigan (Fig,l). Ten of these structures are permanent- type; the balance are of the portable-type. The purpose of these installations is two-fold: first, to provide much needed ad- ditional sites for experimentation with ether techniques of con- trol; second, to extend the active control program throughout the United States waters of Lake Huron and into Lake Michigan, This plan, requiring the organization of two additional con- trol zones in Lake Huron and one in northern Lake Michigan, effects complete control of the lamprey in the United States waters of Lake Huron and places two pilot structures in the first organized control unit in Lake Michigan (see ^ig.i, Zones H-2, H-3, and M-l) . These 1% structures, predominatly of the permanent -type, will cost an estimated $165,882.00 to install. By careful planning for the best utilization of personnel and equip- ment, it has been computed that operating costs can be held to about $76,969.00 annually. This ratio of initial cost to annual operating expenses can be considered typical of that which wi 11 be met in almost any area of the Great Lakes in initiating a program centered exclusively around mechanical control measures. u7 Literature Cited. Applegate, Vernon C. 1950. Natural History of the sea lamprey in Lake Michigan. U. S. Dept. of Int., Fish and Wildl. Serv., Spec. Sci. Rept. : Fisheries No. 55 Shetter, David S. 19i;9. A brief history of the sea lamprey problem in Michigan waters. Trans. Am. Fish. Soc, 76 (19U6), pp. 160-176. U8 Appendix List of common and scientific names of fishes mentioned in this report Black bullhead Brook trout Common shiners Creek chubs Great Lakes Longnosed dace Lake Chub Lake trout Log perch Muddler Mudminnow Northern pike Pumpkinseed sunfish Rainbow trout Rock bass Sea lamprey Silver lamprey Smallmouth bass Smelt Sturgeon sucker Yellow perch Walleye white sucker Ameriurus m. melas Salvelinus f, fontindis No tropin cornutus frontalis Sernotilus a. atromaculatus Rhynichthys c. cataractae Couesius plumbeus Salvelinus ( Cri s ti vomer )n. namaycush Percina caprodes Cottus b. bairdii Umbra limi Esox lucius I orr,is gibbosus Salmo gairdnerii Ambloplite.s rupestris Pctromyzon marinus Ichthyomyzon unicuspis Micropterus d. i olomieu Osmerus mora ax Catostomus c, catostomus Perca flavescens Stizostedion v. vitreum Catostomus £. commersonnii Interior-Duplicating Section Wash., D.C„ h9 963S1 MBL WHOI Library - Serials 5 WHSE 01042