Spawning-Phase Assessment

Mechanical traps are used to monitor sea lamprey spawning migrations in spring and early summer. Traps either are portable (rectangular steel mesh, hoop or fyke nets) or permanent (generally concrete) and usually are associated with a physical or electrical barrier. Trap catch of sea lampreys is a measure of relative abundance. Biological characteristics (sex, weight, length) are recorded from lampreys removed from certain streams.

Mark/recapture studies are conducted in most streams to estimate the spawning population for the year. These estimates are computed using a modified version of Schaefer (1951). Lake estimates are computed based on a relation (y=ax) of average stream discharge (x) to the estimated number of adult lampreys that enter tributaries (y).

Figure 8: Location of streams where assessment traps were operated in 1995

Lake Superior Spawning-Phase Assessment

In 1995, 2,967 sea lampreys were trapped in 21 tributaries (Table 14, Fig. 8).
The estimated population of spawning-phase sea lampreys for the south shore of Lake Superior was 24,081 [13,649 west (y=180.71x; r2=.75, P<0.10) and 10,432 east (y="146.11x;" r2=".88," P<0.01) of the Keweenaw Peninsula; Table 15].
Spawning runs were monitored through cooperative agreements in eight streams with the Great Lakes Indian Fish and Wildlife Commission (Amnicon, Middle, Bad, Firesteel, Misery, Traverse, Silver, and Huron rivers) and in the Brule River with the Wisconsin Department of Natural Resources.
Fig. 2 shows a downward trend of spawning populations in the U.S. waters of western Lake Superior for 1986-95, and a relatively stable trend in the east with a slight increase in 1995.


Table 14.  Stream, number, estimated population, trap efficiency and biological characteristics of adult sea lampreys captured in assessment traps in tributaries of Lake Superior, 1995.  (Number in parentheses corresponds to location of stream in Fig 8).


Stream			Number	Spawner		Trap		Number		Percent		Mean Length (mm)	Mean Weight (g)
			Caught	estimate	efficiency	sampled (1)	males (2)	Males	Females		Males	Females


UNITED STATES

  Tahquamenon R. (38)	558	2,784		19		283	 	59		442	446		226	242
  Betsy R. (39)		47	120		39		36		58		440	425		189	190
  Miners R. (40)	1	-		 -		0	 	 -		-	  -	 	-	  -
  Rock R. (41)		406	815		50	  	0		 612	 	-	  -	 	-	  -
  Big Garlic R. (42)	0	-	 	-	 	0	 	 -	  	-	  -	 	-	  -
  Iron R. (43)		14	-	 	-	  	0	 	 -	 	-	  -	  	-	  -
  Huron R. (44)		34	140		24	  	1		100		420	  -		227	  -
  Silver R. (45)	23	85		27	 	4	 	75		435	401		228	124
  Traverse R. (46)	0	-		 -	  	0	  	-	  	-	  -	 	 -	  -
  Misery R. (47)	189	413		46	  	0	  	-	 	 -	  -	 	 -	  -
  Firesteel R. (48)	20	-	 	-	  	1		100		413	  -		198	  -
  Bad R. (49)		237	1,931		12		 69		 25		398	417		181	172
  Brule R. (50)		1,177	1,693		70		149	 	56		446	425		214	191
  Middle R. (51)	21	46		46	 	 5	 	60		438	434		105	176
  Amnicon R. (52)	22	0		 -	 	 4	 	25		400	441		176	165

Total or average	2,749					552		56		440	433		217	210

CANADA

  Neebing McIntyre R. (53)51	218	23	0		 -		-		-	  -		-	-
  Wolf R. (54)		10	-	 -	0	  	 60 (2)	 	-	 	-	  -	 	-	-
  Pancake R. (55)	31	-	 -	0	  	-	  	-	 	-	  -	 	-	-
  Carp R. (56)		62	119	52	0	  	-	  	-	 	-	  -	  	-	-
  Stokely Cr. (57)	49	78	63	0	  	-	  	-	  	-	  -	  	-	-
  Big Carp R. (58)	15	17	88	0	  	-	 	-	  	-	  -	  	-	-

Total or average	218			0		60		-		-	-		-	-

Grand total or average	2,967			552	 	56		440		433	2		17	210


1  The number of lampreys from which all length and weight measurements were determined.
2  Percent males generally determined from internal body examination of the number sampled.  In the Rock and Wolf rivers,
 lampreys were examined externally for secondary sexual characteristics to determine percent males.


Table 15.  Mean discharge for U.S. streams west  and east of Keweenaw Bay in Lake Superior from May 6-June 30, 1986-90, ranked as primary and secondary producers of sea lampreys, and the estimated number of spawning phase sea lampreys in 1995.
[Population estimates were calculated from stratified multiple mark/recapture studies, linear regressions relating past years trap catch to mark/recapture estimates, or trap efficiencies from mark recapture studies conducted from 1986-93 in 9 of 15 streams with traps.  A simple linear regression estimates populations for all streams by the relation of mean stream discharge to the number of lampreys entering the 9 tributaries.]

		Primary Streams							Secondary Streams

		Discharge	Pop. Est						Discharge	Pop. Est.
Stream		m(3)/s		Mark/Recap	Regression		Stream		m (3)/s		Regression




WEST									WEST
Nemadji		13.87		-		2,506			Washington	0.82		15
Amnicon		6.80		-		1,229			Arrowhead	9.82		177
Middle		1.42		46		257			Poplar		1.27		23
Brule		5.52		1,693		998			Gooseberry	0.08		1
Red Cliff	0.03		-		5			Split Rock	0.28		5
Bad		12.37		1,931		2,235			Sand		0.31		6
Ontonagon	29.18		-		5,273			Black		2.75		50
East Sleeping	0.74		-		134			Cranberry	1.70		31
Firesteel	1.90		-		343			Potato		1.02		18
Misery		1.39		413		251			Elm		0.59		11
									Salmon Trout	1.25		23
									Fish		2.21		40
									Poplar		0.99		18

Subtotal (West)	73.22		4,083		13,231			Subtotal (West)	23.09		418
        (w/  traps)29.40	4,083		5,313
        (w/o traps)43.82	-		7,918

EAST									EAST
Traverse	0.59		-		86			Big Gratiot	0.34		5
Sturgeon	17.18		-		2,510			Eliza		0.03		0
Falls		1.73		-		253			Dead		1.42		21
Silver		1.95		85		285			Sand		0.45		7
Slate		0.54		-		79			Five Mile	0.06		1
Ravine		0.59		-		86			Beaver Lake Outlet0.48		7
Huron		3.08		140		450			Sable		0.28		4
Salmon Trout	1.58		-		231			Galloway	0.11		2
Iron		2.80		-		409			Pendills	0.59		9
Big Garlic	0.42		-		61			Laughing Whitefish0.71		10
Little Garlic	0.31		-		45
Harlow		0.57		-		83			Subtotal (East)	4.47		66
Chocolay	2.91		-		425
Rock		0.93		815		136			Secondary
									Lake Total	27.56		484
Au Train	3.03		-		443
Furnace		0.17		-		25
Miners		1.08		-		158
Sucker		2.12		-		310
Two Hearted	6.14		-		897
Little Two Hearted0.96		-		140
Betsy 		2.09		120		305
Tahquamenon	18.65		2,784		2,725
Waiska		1.53		-		224

Subtotal (East)	70.95		3,944		10,366
       (w/  traps)31.59		3,944		4,615
       (w/o traps)39.36		-		5,751

Primary Lake Total144.17	8,027		23,597


TOTAL SOUTH SHORE DISCHARGE:                171.73 m3/s

TOTAL SOUTH SHORE POPULATION ESTIMATE:         24,081

Lake Michigan Spawning-Phase Assessment

In 1995, 18,729 sea lampreys were trapped at 14 sites in 13 tributaries (Table 16, Fig. 8).
Spawning runs were monitored in six streams through cooperative agreements with the Grand Traverse Band of Chippewa and Ottawa Indians (Betsie and Boardman rivers), Michigan Department of Natural Resources (Jordan River), Consumers Power (Manistee River), and volunteers (Little Manistee River).
Fig. 3 shows the trend of spawning populations in Lake Michigan for 1986-95.

Table 16.  Stream, number, estimated population, trap efficiency, and biological characteristics of adult sea lampreys captured in assessment traps in tributaries of Lake Michigan, 1995.  (Number in parentheses corresponds to location of stream in Fig. 8.)



Stream			Number	Spawner		Trap		Number		Percent		Mean Length (mm)	Mean Weight (g)
			Caught	estimate	efficiency	sampled (1)	males (2)	Males	Females		Males	Females


UNITED STATES

Carp Lake R. (22)	69	-		-		46		33		437	444		166	179
Jordan R. (23)		5	-		-		0		-		-	-		-	-
Deer Cr. (24)		4	-		-		2		50		460	-		199	-
Boardman R. (25)	165	-		-		46		43		460	454		63	268
Betsie R. (26)		831	2,704		28		302		28		472	473		139	249
Manistee R. (27)	830	-		-		0		-		-	-		-	-
  Little Manistee R.	23	-		-		23		52		481	459		257	241
St. Joseph R. (28)	50	-		-		43		30		420	396		193	186
East Twin R. (29)	12	-		-		3		33		432	407		136	155
Fox R. (30)		0	-		-		0		-		-	-		-	-
Oconto R. (31)		62	-		-		33		67		495	525		252	312
Peshtigo R. (32)	657	2,049		32		156		56		464	494		263	287
Menominee R. (33)	94	445		21		9		44		483	471		252	248
Manistique R. (34)	15,927	25,077		64		0		41		-	-		-	-

Total or average	18,729	30,275		36		663		41		466	468		244	247

1The number of lampreys from which all length and weight measurements were determined.
2Percent males generally determined from internal body examination of the number sampled.  In the Manistique River,
 15,917 additional lampreys were examined externally for secondary sexual characteristics to determine percent males.

Lake Huron Spawning-Phase Assessment

In 1995, 46,974 sea lampreys were trapped in 16 tributaries (Table 17, Fig. 8).
The estimated population for Lake Huron is 346,859 [321,119 north (y=1132.60x; r2=.88, P<0.01) and 25,740 south (y="177.08x;" r2=".86," P<0.05) of a line from Alpena, Michigan to Espanola, Ontario, Table 18]. This estimate is the result of a cooperative effort between the Service and Department and combines the data of both agencies.
Spawning runs were monitored through cooperative agreements in two rivers. Traps in the Albany River were monitored by the Chippewa/Ottawa Treaty Fishery Management Authority and in the Tittabawassee River by Dow Chemical U.S.A.
Additional trap sites were established at the Great Lakes Tissue Plant in the Cheboygan River and at the E.B. Eddy dam on the Spanish River.
A permanent trap replaced two portable traps in the Tittabawassee River. Trap efficiency increased from 7% in 1994 to 13% in 1995.
Figure 4 shows the upward trend of spawning populations in Lake Huron for 1986-93, followed by an abrupt drop for 1994-95.


Table 17.  Stream, number, estimated population, trap efficiency, and biological characteristics of adult sea lampreys captured in assessment traps in tributaries of Lake Huron, 1995.  (Number in parentheses corresponds to location of stream in Fig. 8).


Stream			Number	Spawner		Trap		Number		Percent		Mean Length (mm)	Mean Weight (g)
			Caught	estimate	efficiency	sampled (1)	males (2)	Males	Females		Males	Females


UNITED STATES

Saginaw R. (16)
   Tittabawassee R. 	1,702	10,157		17		573		49		462	473		222	235
     Big Salt R. 	100	443		23		27		52		456	444		207	208
     Pine R. 		121	951		13		43		51		500	469		291	237
     Chippewa R.	6	-		-		0		 -		-	-	  	-	-
     Cass R. 		24	82		29		0		 -		-	-		-	-
East Au Gres R. (17)	231	1,914		12		23		52		442	493		195	265
Au Sable R. (18)	930	6,045		15		68		48		421	479		190	261
Devils R. (19)		224	897		25		68		32		440	462		183	210
Ocqueoc R. (20)		3,717	5,684		65		0		43		-	-	  	-	 -
Cheboygan R. (21)	26,237	30,488		86		0		47		-	-		-	 -
Carp R. (35)		549	5,153		11		2		50		477	426		218	194
Albany R. (36)		52	101		52		7		43		383	477		127	194
St. Marys R. (37)	1,038	See Canada	See Canada	0		60		-	-	 	-	  -
Total or Average	34,931					811		48		458	472		219	234

CANADA

St. Marys R. (37)	8,172	19,608		47		0		54		-	-		  -	  -
Echo R. (59)		2,136	4,167		51		0		54
Thessalon R. (60)	1,732	6,371		27		0		54
Spanish R. (61)		3	-		-		0		 -		-	-	  	-	  -
Total or Average	12,043					0		54
Grand total or average	46,974					811		53		458	472		219	234


1The number of lampreys from which all length and weight measurements were determined.
2Percent males generally determined from internal body examination of the number sampled.  But at six trapping sites where no sampling was conducted males determined by external examination of lampreys (Ocqueoc - 3,717, Cheboygan - 26,237, St. Marys US - 953, St. Marys Can. - 8,172, Echo/Thessalon combined - 3,540).


Table 18.  Mean discharge for streams north and south of Alpena, Michigan-Espanola, Ontario in Lake Huron, ranked as primary and secondary producers of sea lampreys and the estimated number of spawning-phase sea lampreys in 1995.
[Population estimates were calculated from results of stratified multiple mark/recapture studies.  A linear regression estimates populations for all streams by the relation of mean stream discharge to the number of adult lampreys entering 10 tributaries.]




		Primary Streams							Secondary Streams

		Discharge	Pop. Est						Discharge	Pop. Est.
Stream		m(3)/s		Mark/Recap	Regression		Stream		m (3)/s		Regression

NORTH									NORTH
St. Marys	2,122.50	19,608		19,608			Munuscong	1.44		163
L. Munuscong	0.62		-		705			Carlton		0.14		16
Caribou		0.42		-		481			Ceville		1.08		122
Albany		0.76		101		865			Hessel		0.20		22
Trout		0.31		-		353			Steels		0.23		26
Beavertail	0.68		-		769			Nuns		0.62		71
McKay		0.51		-		577			Mulligan	0.40		45
Pine		6.34		-		7,180			Sucker		0.20		22
Carp		8.12		5,153		9,199			Two Tree	0.45		51
Cheboygan	23.97		30,488		27,149			Richardson	0.31		35
Elliot		0.42		-		481			H-68		0.08		10
Greene		0.17		-		192			Livingstone	0.06		6
Black Mallard	0.28		-		321			Blind		6.34		718
Ocqueoc		2.75		5,684		3,109			Lauzon		0.37		42
Schmidt		0.74		-		833			Spragge		0.20		22
Trout		0.91		-		1,026			Serpent		9.85		1,115
Root		2.29		-		2,596			Spanish		215.84		24,447
Garden		7.98		-		9,039			Silver		0.48		54
Echo		1.61		4,167		1,827			Sand		0.28		32
Watson		0.14		-		160			Manitou		1.90		215
Gordon		0.11		-		128			Blue Jay	0.59		67
Browns		0.20		-		224
Koshkawong	0.68		-		769
Thessalon	10.47		6,371		11,859
Mississagi	170.37		-		192,957
Mindemoya	0.96		-		1,090
Timber Bay	0.28		-		321

Subtotal (North)	2,364.61	71,572	293,818			Subtotal (North)	241.06		27,301
         (w/ traps)	2,170.19	71,572	73,616
         (w/o traps)	194.42	0	220,202

SOUTH									SOUTH
Devils		0.71		897		125			Shiawassee	13.19		234
AuSable		43.70		6,045		7,738			Cass		13.56		240
Tawas		2.21		-		391			Mill		0.06		1
E. AuGres	2.52		1,914		446			Pine		1.42		25
Rifle		9.68		-		1,714			Chikanishing	0.34		6
Tittabawassee	49.38		10,157		8,745			French		216.83		3,840
									Still		1.75		31
									Magnetawan	52.64		932
									Naiscoot	1.98		35
									Boyne		1.13		20
									Musquash	56.60		1,002
									Sturgeon	0.88		16
									Nottawasaga	7.78		138
									Sauble		3.42		61

Subtotal (South)108.19		19,013		19,159		Subtotal (South)	371.58		6,581
(w/ traps)	96.30		19,013		17,054
(w/o traps)	11.89		0		2,105
Primary Lake
Total		2,472.80	90,585		312,977			Secondary Lake
										 Total	612.64		33,882

TOTAL DISCHARGE    2,537.80 m3/s
TOTAL POPULATION ESTIMATE     346,859

Lake Erie Spawning-Phase Assessment

In 1995, 504 sea lampreys were trapped in 8 tributaries (Table 19 , Fig. 8).
Fig. 5 shows the trend of spawning populations in Lake Erie for 1986-95. The population dropped in 1989-90 in the aftermath of the 1986/87 first round of treatments, increased slightly in 1991-92, and decreased and stabilized during 1993-95.

Table 19.  Stream, number, estimated population, trap efficiency and biological characteristics of adult sea lampreys captured in assessment traps in tributaries of Lake Erie, 1995.  (Number in parentheses corresponds to location of stream in Fig. 8)

Stream			Number	Spawner		Trap		Number		Percent		Mean Length (mm)	Mean Weight (g)
			Caught	estimate	efficiency	sampled (1)	males (2)	Males	Females		Males	Females


UNITED STATES

Cattaraugus Cr. (10)	446	780		57		212		57		490	493		285	287
Crooked Cr. (11)	1	-		-		1		100		381	-		170	-
Raccoon Cr. (12)	0	-		-		0		-		-	-		-	-
Conneaut Cr. (13)	0	-		-		0		-		-	-		-	-
Grand R. (14)		18	-		-		3		67		460	480		297	284
Chagrin R. (15)		2	-		-		0		-		-	-		-	-
Total or average	467					216		58		489	493		285	287

CANADA
Big Cr. (62)		8	-		-		0		-		-	-		-	-
Young's Cr. (63)	29	-		-		0		-		-	-		-	-
Total or average	37	-		-		-		-		-	-		-	-

Grand Total or average	504					216		58		489	493		285	287

Lake Ontario Spawning-Phase Assessment

In 1995, 4,241 sea lampreys were trapped at 16 sites in 15 tributaries (Table 20 , Fig. 8).
Low water levels persisted throughout April-June and decreased effectiveness of traps at several sites in the U.S.
The catches from the assessment traps indicate that lamprey populations in Lake Ontario have remained relatively stable, during 1986-95 (Fig. 6).

Table 20.  Stream, number, estimated population, trap efficiency and biological characteristics of adult sea lampreys captured in assessment traps in tributaries of Lake Ontario, 1995  (Number in parentheses corresponds to location of stream in Fig. 8).

Stream			Number	Spawner		Trap		Number		Percent		Mean Length (mm)	Mean Weight (g)
			Caught	estimate	efficiency	sampled (1)	males (2)	Males	Females		Males	Females


UNITED STATES
Cattaraugus Cr. (10)	446	780		57		212		57		490	493		285	287
Black R. (1)		536	4,454		12		49		53		458	468		216	247
South Sandy Cr. (2)	15	-		-		0		-		-	-		-	-
Salmon R. (3)		0	-		-		0		-		-	-		-	-
Grindstone Cr. (4)	24	-		-		0		-		-	-		-	-
Little Salmon R. (5)	5	-		-		0		-		-	-		-	-
Catfish Cr. (6)		0	-		-		0		-		-	-		-	-
Oswego R. (7)		0	-		-		0		-		-	-		-	-
    Black Cr. 		0	-		-		0		-		-	-		-	-
Sterling Valley Cr. (8)	6	-		-		0		-		-	-		-	-
Sterling Cr. (9)	14	-		-		0		-		-	-		-	-
Average or total	600					49		53		458	468		216	247

CANADA
Humber R. (64)		1,528	2,736		56		282		60		-	-		-	-
Duffins Cr. (65)	994	1,346		74		180		53		-	-		-	-
Bowmanville Cr. (66)	186	972		19		39		44		-	-		-	-
Graham Cr. (67)		156	296		53		36		39		-	-		-	-
Port Britain Cr. (68)	47	92		51		10		50		-	-		-	-
Shelter Valley Cr. (69)	730	1,359		54		151		52		-	-		-	-
Average or total	3,641					698		54		-	-		-	-

Grand total or avg	4,241	11,255		46		747		54		458	468		216	247

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