A Natural History of Millbrook Marsh,
A Wetland In An Urbanizing Setting

Fish

The fish of Millbrook Marsh were most recently inventoried in August 1997 (Brooks et al. 1998). The streams were considered as 3 individual reaches when analyzing the fish communities. Thompson Run extended from the mouth at Slab Cabin Run, upstream to the bridge at Route 26. Lower Slab Cabin Run extended from the bridge at Puddintown Road, upstream to the confluence with Thompson Run and Upper Slab Cabin Run, from the confluence with Thompson Run, upstream to the bridge at Route 26.

Wild brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss), white suckers (Catostomus commersoni), and slimy sculpins (Cottus cognatus) were found in both Thompson Run and Lower Slab Cabin Run (Table 6-9). Wild brown trout, white suckers, blacknosed dace (Rhinichthys atratulus), and creek chubs (Semotilus atromaculatus) were found in Upper Slab Cabin Run (Brooks et al. 1998). The Stream Survey Report of 1941 listed abundant "fish food minnows", brook trout, now missing, brown trout, rainbow trout, minnows, and suckers in Lower Slab Cabin Run and classified it as a "Brown Trout Stream." The same fish species were found in Thompson Run (Donley 1941). Station 3 of the PennDOT study was located in Upper Slab Cabin Run, and the fish species were inventoried in 1979 (PennDOT 1981). The fish found were golden shiner (Notemigonus erysoleucas), longnose dace (Rhinichthus cataractae), creek chub, white sucker, largemouth bass (Micropterus salmoides), and pumpkinseed sunfish (Lepomis gibbosus). These fish species are representative of warm water, despite the classification of Slab Cabin Run as a cold water stream.

For the 1997 inventory, density and biomass estimates were made for brown trout only since rainbow trout were not captured consistently in any of the 3 reaches (Table 6-11). Density and biomass estimates of brown trout were highest in Thompson Run (4800/ha, 423 kg/ha), followed by Lower Slab Cabin Run (983/ha, 106 kg/ha) and Upper Slab Cabin Run (761/ha, 106 kg/ha). Recruitment of young-of-the-year fish, those from 1997, was good in all 3 stream reaches, as evidenced by the first peak in length-frequency distribution of fish 139 mm and smaller. A gap in 1 year old fish 139-169 mm long indicates poor recruitment during 1996, most likely due to the severe flooding that occurred early that year.

The change in the fish population in Slab Cabin Run and Thompson Run includes a lowered species richness and a much higher proportion of Brown trout than in the past (Table 6-10). Pumpkinseed and Golden shiners have not been seen in either stream since 1979, in addition to the loss of Largemouth bass, Longnose dace and Goldfish. These fish species that have disappeared, though, are warm water fish. The whole of the Spring Creek watershed is designated at least Cold Water Fish, with some stream reaches High Quality CWF. The temperature criteria for CWF is the most stringent. Temperature change may not exceed more than 2° F (1.1° C) and the allowed temperatures range through the year from a maximum of 38° F (3.3° C) in January to a maximum of 66° F (18.8° C) in July and August The native Brook trout, a cold water fish, is not in any of the inventories, though it was throughout the Spring Creek watershed, including Millbrook Marsh, in the 1941. It is still found in streams throughout the watershed. Brown trout dominate both Slab Cabin Run and Thompson Run at this time, with a very large increase in population since 1989.

Table 6-9
1997 Fish Collected in Millbrook Marsh

Species

Common name

Thompson Run

Lower Slab Cabin Run

Upper Slab Cabin Run

Catostomus commersoni White sucker

2

2

80

Cottus cognatus Slimy sculpin

63

38

6

Oncorhynchus mykiss Rainbow trout

13

3

0

Rhinichthys atratulus Blacknose dace

0

0

10

Salmo trutta Brown trout

313

253

147

Semotilus atromaculatus Creek chub

0

0

2

Totals

391

296

245

Electrofishing data for brown and rainbow trout from Thompson Run is from August 8 and 11, 1997, Run 1; August 14, 1997, Run 2. Data for brown and rainbow trout from Lower Slab Cabin Run is from August 5 and 7, 1997, Run 1; August 14, 1997, Run 2. Data for brown trout from Upper Slab Cabin Run is from August 7 and 8, 1997, Run 1; August 14, 1997, Run 2. Data for non-trout fish from Thompson and Slab Cabin Run is from August 14, 1997.

Table 6-10
Millbrook Marsh Fish Inventory 1979-1997

   

1941

1979

1987

1989

1997

Species Common Name

Lower Slab Cabin Run

Thompson Run

Upper Slab Cabin Run

Slab Cabin Run

Lower Slab Cabin Run

Thompson Run

Upper Slab Cabin Run

Thompson Run

Upper Slab Cabin Run

Lower Slab Cabin Run

  Minnows

*

*

               
Carassius auratus Goldfish          

*

       
Catostomus commersoni White sucker

*sp.

*sp.

*

*

11

*

*

2

80

2

Cottus cognatus Slimy sculpin        

4

*

 

63

6

38

Micropterus salmoides Largemouth bass    

*

*

 

*

       
Notemigonus erysoleucas Golden shiner      

*

           
Oncorhynchus mykiss Rainbow trout

*

*

         

13

 

3

Rhinichthys atratulus Blacknose dace        

1

 

*

 

10

 
Rhinichthys cataractae Longnose dace    

*

*

   

*

     
Salmo trutta Brown trout

*

*

   

12

65

6

313

147

253

Salvelinus fontinalis Brook trout

*

*

               
Semotilus atromaculatus Creek chub    

*

*

3

*

   

2

 
Lepomis gibbosus Pumpkinseed    

*

*

           
Total species  

5

5

5

6

5

6

4

4

5

4

Table 6-11
1997 Electrofishing Data for Brown Trout in Millbrook Marsh Streams

Brown Trout

Thompson Run

Lower Slab Cabin Run

Upper Slab Cabin Run

Length

Group

(mm)

Total

caught

(N)

Mean

Weight

(g)

g*N

(kg)

Total

caught

(N)

Mean

weight

(g)

g*N

(kg)

Total

caught

(N)

Mean

weight

(g)

g*N

(kg)

60-69

4

0

0.00

70-79

8

4

0.16

3

4

0.02

13

4

0.09

80-89

39

7

1.38

20

7

0.26

22

7

0.26

90-99

40

14

2.83

33

14

0.84

17

14

0.41

100-109

51

16

4.13

22

16

0.64

10

16

0.27

110-119

38

18

3.46

5

18

0.16

1

18

0.03

120-129

11

20

1.11

2

-

-

1

-

-

130-139

4

25

0.51

0

0

0.00

0

0

0.00

140-149

0

0

0.00

0

0

0.00

1

0

0.00

150-159

1

41

0.21

1

40

0.07

0

41

0.00

160-169

0

0

0.00

0

0

0.00

1

-

-

170-179

2

57

0.58

6

62

0.68

1

60

0.10

180-189

7

75

2.66

5

72

0.66

2

75

0.26

190-199

8

81

3.30

5

78

0.71

4

82

0.56

200-209

11

98

5.45

11

94

1.89

3

93

0.48

210-219

11

110

6.15

17

104

3.23

3

105

0.54

220-229

17

126

10.88

14

115

2.94

6

125

1.28

230-239

10

148

7.50

11

128

2.57

3

135

0.69

240-249

7

159

5.62

16

153

4.46

7

104

1.25

250-259

6

192

5.82

14

164

4.19

8

188

2.56

260-269

3

215

3.26

20

187

6.84

4

199

1.36

270-279

5

230

5.82

14

211

5.39

1

220

0.38

280-289

2

258

2.61

5

241

2.20

2

255

0.87

290-299

5

282

7.14

8

252

3.69

2

285

0.97

300-309

2

315

3.19

7

275

3.52

4

326

2.23

310-319

6

341

10.35

6

317

3.47

4

332

2.27

320-329

4

396

8.02

1

400

0.73

5

378

3.23

330-339

2

420

4.25

1

380

0.69

4

395

2.70

340-349

6

442

13.44

2

445

1.63

2

410

1.40

350-359

1

380

1.92

2

450

1.64

5

499

4.26

360-369

3

517

7.84

0

0

0.00

5

505

4.31

370-379

0

0

0.00

1

580

1.06

1

490

0.84

Table 6-11 continued
1997 Electrofishing Data for Brown Trout in Millbrook Marsh Streams

Brown Trout

Thompson Run

Lower Slab Cabin Run

Upper Slab Cabin Run

Length
Group
(mm)

Total
caught
(N)

Mean
Weight
(g)

g*N
(kg)

Total
caught
(N)

Mean
weight
(g)

g*N
(kg)

Total
caught
(N)

Mean
weight
(g)

g*N
(kg)

380-389

1

660

3.34

1

640

1.17

0

0

0.00

390-399

1

640

3.24

400-409

1

700

3.54

410-419

1

820

1.40

TOTALS

313

139.72

253

49.87

147

34.97

Biomass

423 kg/ha

106 kg/ha

106 kg/ha

Population estimate and 95% confidence interval

868, 1584, 3843

355, 462, 700

179, 251, 406

Table 6-12
1997 Electrofishing Data for Rainbow Trout in Millbrook Marsh Streams

Rainbow Trout

Thompson Run

Lower Slab Cabin Run

Length (mm)

Weight (g)

Length (mm)

Weight (g)

106

-

148

35

112

-

152

40

139

35

157

43

149

-

150

40

152

40

157

-

157

50

161

50

166

60

167

55

426

840

452

1070

On to Amphibians and Reptiles