fisheries survey 1969

Item Type monograph

Authors Nott, F.J.

Publisher River Authority

Download date 01/10/2021 13:24:58

Link to Item http://hdl.handle.net/1834/27149 DEVON RIVER AUTHORITY

RIVER DART FISHERIES SURVEY

1969

HQ LIBRARY Head of Administration South West Water Peninsula House Rydon Len© EX2 7HR CONTENTS

A - INTRODUCTION

B - METHODS

C - RESULTS

D - DISCUSSION

E - ACKNOWLEDGEMENTS

F - BIBLIOGRAPHY A. INTRODUCTION

This the second fisheries survey of the River Dart was made between April and July 1969. In addition to the tributaries examined in the 1965 survey, further sections were studied on the River Hems and the Holy Brook (Map I).

Reference should be made to the River Dart Survey Report 1965 for introductory information on Pollution, Anglings Netting, Spawning and Water Abstraction,, Current data on anglers' and netsmen’s returns are included in the Appendix.

Bo METHODS

Forty seven sections were examined which were accessible and fishable by electro-fishing methods.

The sections were grouped as follows:-

West Dart and tributaries - 14 (11 in 1965) East Dart and tributaries - 10 (10 in 1965) River Dart and tributaries below - 23 (10 in 1965).

Each section was named by reference to a nearby bridge or local land­ mark.

Section Grid Area Date Sur No . Name Ref. sq ,m. 1969

1 A.384 Road Bridge 588750 426 25/6

2 Cairns Bridge 595742 585 25/6

3 Beardown Farm 613753 502 17/6

4 * Upstream Powder Mill 628775 209 16/6

5 Downstream Powder Mill 633770 418 13/6

6 * Cherry Brook Bridge 632748 418 16/6

7 Crockern Tor 609758 368 5/8

8 Two Bridges 609750 1 s 184 2/7

9 Prince Hall 627739 946 2/7

10 * Upstream Swincombe Foot 648738 1,062 9/7

11 Huccaby 659729 689 7/7

12 * Upstream Water Intake 627715 481 11/6

13 Swincombe Farm 642725 669 12/6

14 Sherberton Farm 647730 502 12/6 Section Grid Area Date Surveyed No. Name R e f . sq.m. 1969

15 Hartland Tor 640798 281 21/7

16 650788 803 3/7

17 Believer 658774 455 3/7

18 Laughter Hole 662758 555 15/7

19 Brimpts Farm 672739 828 16/7

20 Stats Bridge 667805 84 10/4 Cor Merripits Bridge)

21 Pizwell 669785 293 14/4

22 * Runnage Bridge 670777 251 9/4

23 Riddon Farm 677764 167 8/8

24 Sherril 672.750 314 8/7

25 * Dartmeet 672731 1,129 22/7

26 New Bridge 712709 428 17/7

27 * Bridge 731706 1,311 17/7

28 * Queen of the Dart 733692 1,484 25/7

29 * Austins Bridge 751659 615 24/7

30 * Staverton 788638 1,171 25/7

31 Grendon Bridge 688785 334 4/6

32 Cator Court Bridge 690765 385 4/ 6

33 Shallowford Bridge 692756 477 5/6

34 Pondsworthy 701738 396 5/6

35 * Bag Park Bridge 722787 251 6/6

36 Widecombe Bridge 721768 205 6/6

37 Cockingford Bridge 718751 397 13/6

38 Lower Lodge Bridge 719720 468 10/6

39 * Hawson Court 720683 180 23/6

40 * Rew 758707 2.50 24/6

41 Pridhamsleigh Bridge 748677 209 24/ 6

-2- Section Grid Area Date Surveyed N o . Name Ref. sq .m. 1969

42 * Bilberry Hill 728666 464 23/6

43 * Bow Bridge 801650 241 26/6

44 * 815630 410 26/6

45 * Yeo Bridge 758595 418 1/7

46 * Roister 772563 460 1/7

47 Growdy Mill 792561 502 27/6

* indicates new or changed sections.

Sampling Techniques

In this survey "parr of the year" - those fish hatched in the spring of 1969 - were not assessed since their small size made both capture and identification difficult.

The following descriptions are used in the text to denote the different year classes of parr and fry;

0+ - fish hatched in 1969 1+ - fish hatched in 1968 2+ - fish hatched in 1967

In the previous survey each section was fished a number of times until the survey crew judged that very few fish remained. In order to reduce the time spent at each section and to expedite the completion of the survey, each section was fished three times.

1. The number of fish caught in each successive 'fish through' was plotted against the sum ) of previous catches.

2. The intercept on the x axis giving a calculated value of the population in the section. (Le Cren & Seber, 1967). CATCH

“3- The number of fish caught was 137 but the calculated total was 148. Complete fishing out of the section would have undoubtedly produced more than the number actually caught.

In some sections the first 'fish through* yielded fewer fish than the secondj, in which case the first catch figure was not used in the calculation. Second and subsequent 'fish through* catches were used. The catch from the first 'fish through' was added to the calculated total.

The first 'fish through' is often less effective than second and third as the initial stunning causes fish to seek cover from which they are drawn by second and subsequent sweeps.

It was not possible in field conditions to distinguish between the young stages of migratory and brown trout. Salmonid fish were recorded as either 'salmon' or 'trout' except in the case of smolts or adult migratory trout.

C. RESULTS

Salmon - Salmo salar

(a) Adults

Five adult salmon were caught during the survey at the Brimpts Farm section on the . This is not significant since the deep water sections favoured by adults were not surveyed for juvenile salmonids.

(b) Parr

The numbers of parr found in each section are given in Tables 1, 2 and 3.

The size distribution of the salmon parr from each section is given in Tables 4, 5 and 6. Also shown are the sample totals, calculated totals and the ratio of sample to calculated total as a percentage. For comparison the population totals for the 1965 survey are included.

The population densities of salmon and trout from all sections are given in Tables 10, 11 and 12. The 1+ parr found in this survey would migrate as two-year smolts in the spring of 1970 or as three- year smolts in 1971. The 2+ p.arr" caught in this survey would migrate as three-year smolts in spring 1970.

River Dart Scale Readltfg reports 1962-196-7 show that over 90% of parr become smolts and migrate after two river winters. The following table shows the proportions of 1, 2 and 3-year smolts in each scale sample: Year 7o 1-year 7o 2-year % 3-year Smolts Smolts Smolts 1962 3.2 86.9 9.9 1963 2.1 91.0 6.9 1964 2.2 92.9 4.9 1965 1.9 92.0 6.1 1966 1.6 95.2 3.2 1967 0.5 97.7 1.7

Average 1.97 92.36 5.67

The results show that the percentage of 1 and 3-year smolts has tended to decline between 1962 and 1967 and that the percentage of 2-year smolts has tended to increase during the same period.

Examination of Tables I, 2 and 3 show that salmon parr were found in the majority of sections surveyed.

The Blackbrook river was studied at two sites and the average salmon parr index was found to be 10.5 per 100 sq.m. (8.8 per 100 sq.yds) in comparison with 19.1 trout per 100 sq.m. (15.9 per 100 sq.yds). In 1965 the salmon parr index was 22.1 parr per 100 sq.yds and 20 trout per 100 sq.yds, thereby showing a marked decline in the salmon parr index in 1969.

One section on the River Cowsic gave average indices of 0.6 salmon per 100 sq.m. (0.5 per 100 sq.yds). Trout were present as 18.5 per 100 sq.m. (15.5 per 100 sq.yds) in comparison with 17.5 trout per 100 sq.yds found in 1965.

In the Cherry Brook the parr density at two sites was found to be 12.6 salmon per 100 sq.m. (10.6 per 100 sq.yds) and 20.7 trout per 100 sq.m. (17.3 per 100 sq.yds). These can be compared with 6.1 salmon and 8.5 trout per 100 sq.yds in 1965.

The West Dart gave, on average, a salmon parr index of 6.4 per 100 sq.m. (5.4 per 100 sq.yds) and 7.5 trout per 100 sq.m. (6.3 per 100 sq.yds). 1965 indices were 6.6 salmon per 100 sq.yds and 5.5 trout per 100 sq.yds.

The salmon parr index was 6.9 per 100 sq.m. (5.8 per 100 sq.yds) and that for trout 9.5 per 100 sq.m. (7,9 per 100 sq.yds, in comparison with 9.3 salmon per 100 sq.yds and 7.5 trout per 100 sq.yds in 1965.

Five sections on the East Dart River gave average indices of 19.6 per 100 sq.m. (16.4 per 100 sq.yds) for salmon and 7.5 per 100 sq.m. (6.3 per 100 sq.yds) for trout. The salmon parr index shows a marked increase over the 1965 figure of 6.5 salmon per 100 sq.yds„ The previous index for trout was 3.6 per 100 sq.yds.

The gave salmon parr indices of 12 per 100 sq.m. (10 per 100 sq.yds) and 37.9 trout per 100 sq.m. (31.7 per 100 sq.yds), in comparison with 7.9 salmon parr and 16.5 trout per 100 sq.yds in 1965.

-5- The River Dart between Dartmeet and was examined in four sections and gave indices of 7.4 salmon per 100 sq.m. (6.2 per 100 sq.yds). One section examined in 1965 gave a salmon parr index of 6.1 per 100 sq.yds. Trout were present as 2,14 per 100 sq.m. (1.8 per 100 sq.yds) in 1969 and 0.7 per 100 sq.yds in 1965.

The gave a salmon parr index of 10.8 salmon per 100 sq.m. (9.04 per 100 sq.yds) in 1969, 10.9 salmon per 100 sq.yds in 1965, whereas the East Webburn had a salmon parr index of 9.3 per 100 sq.m. (7.7 per 100 sq.yds) in 1969 in comparison with 8.7 per 100 sq.yds in 1965. The trout indices in 1969 were 17.5 per 100 sq.m. (14.6 per 100 sq.yds) on the West Webburn and 21.7 per 100 sq.m. (18.1 per 100 sq.yds) on the East Webburn. 1965 figures were 17.5 trout per 100 sq.yds and 20.4 trout per 100 sq.yds respectively.

The River Webburn between Lizwell Meet, where the West and East Webburn join, and its confluence with the River Dart was found to have a salmon parr index of 13.2 per 100 sq.m. (11.1 per 100 sq.yds) and a trout index of 10.7 per 100 sq.m. (8.9 per 100 sq.yds) in 1969.

The River Dart below Buckfastleigh was surveyed at two points and these yielded an average salmon parr index of 1.85 per 100 sq.m. (1.54 per 100 sq.yds) and a trout index of 2.1 per 100 sq.m. (1.7 per 100 sq.yds). No comparable figures were obtained in 1965.

The Holy Brook, which was not surveyed in 1965, gave a salmon parr index of 0.6 per 100 sq.m. (0.5 per 100 sq.yds) and 22.2 trout per 100 sq.m. (18.6 per 100 sq.yds).

The Ashburn Yeo had a salmon parr index of 2.2 per 100 sq.m. (1.8 per 100 sq.yds) in 1969, in comparison with 7.3 per 100 sq.yds in 1965, a marked decrease. Trout were present in this tributary as 15.7 per 100 sq.m. (13.1 per 100 sq.yds) in 1969, their density being 18.4 per 100 sq.yds in 1965. The density of salmon parr would most probably have been lower in 1965 had the second section at Rew been fished.

The River Mardle was found to contain no salmon parr whereas trout were very plentiful, the index being 31 per 100 sq.m. (25.9 per 100 sq.yds). A different site on the Mardle was surveyed in 1965 and was found to have a trout index of 17.1 per 100 sq.yds.

The River Hems was surveyed for the first time in 1969 and found to have a salmon parr index of 5.7 per 100 sq.m. (4.8 per 100 sq.yds) and a trout index of 12.6 per 100 sq.m. (10.5 per 100 sq.yds) in the two sections examined.

The salmon parr index on the River Harbourne in 1969 was 2,3 per 100 sq.m. (1.9 per 100 sq.yds) in three sections surveyed, whereas the one section examined in 1965 gave an index of 3.5 salmon per 100 sq.yds. The index for trout was 10.6 per 100 sq.m. (8.9 per 100 sq.yds) in 1969 and 18.8 per 100 sq.yds in 1965.

Estimation of Salmon Parr Population

The density indices as given only act as a direct comparison between the number of salmon parr and trout present in the various sections.

-6- However, these figures can be extended by taking the total lengths of the rivers, multiplying them by average widths, to find the total area of water. By relating total areas to average parr density indices it is possible to estimate the parr population in different parts of the river and from these to deduce a total population figure for the whole river system.

The sections examined in the Cowsic river and the Holy Brook yielded very few salmon parr (3 and 1 respectively). In view of these low parr indices and the fact that only in exceptional years do spawning adults penetrate these streams, the indices were not used in calculating the salmon parr population.

The river has been divided into a series of 'lengths’ to avoid confusion with the term 'sections' used in connection with the survey. These lengths are listed below, each one being denoted by a letter.

A. Blackbrook river from the West Dart confluence to the Prison Weir at .

B. Cherry Brook from the confluence with the West Dart to the Powder Mills.

C. The from Wistman's Wood to Dartmeet.

D. Swincombe river from the confluence with the West Dart to half a mile above the water intake.

E. The East Dart river from one mile above Postbridge to Dartmeet.

F. The Walla Brook from the confluence with the East Dart to the main road bridge B.3212.

G. The West Webburn river from Challacombe Down to the East Dart confluence.

H. The from Bag Park to Webburn Foot.

I. The River Dart from Dartmeet to Buckfast.

J. River Dart below Buckfast to Staverton.

K. Buckfast River Yeo or Ashburn from Ashburton to the main river confluence.

L. The from Barberton to Bow Creek.

M. The River Hems.

In the following Table the total lengths of the 'lengths', together with average widths and total surface areas, are given. The other columns indicate the parr indices for each length, together with the total parr population for the length.

-7- Length Av» Width Area Parr Total No, of Parr Metres Metres sq »m. Index 1969 1965 A 4,752 4,1 19,019 10,5 2,486 4,612 B 4,752 4,9 26,136 12.6 5,024 1,742 C 13,939 12,8 198,633 6.4 13,904 13,904 D 2,217 6,3 13,776 6.9 861 1,610 E 8,870 10,5 91,930 9,6 7,240 7,136 F 6,336 3,3 21,120 12,0 2,455 2,555 G 8,553 4,5 38,016 10.8 6,938 5,122 H 5,702 7,2 40,550 9.3 5,676 5,322 I 17,100 18,0 304,000 7.4 23,560 23,189 J 5,702 25,2 141,926 1.8 2,731 - K 2,851 2,7 7,603 2.12 1,245 693 L 9,900 4,8 46,640 2.3 1,107 2,040 M 5,870 3,6 20,905 5.7 2,744

75,971 67,925 ......

The parr population is estimated to be 76,000.

If the criterion (Elson, 1957) for survival of parr from yearling to smolt, used in the 1965 Survey report of 657, is applied, an estimated 49,000 parr will survive to pre-smolt stage. A further loss of between lot and 20% is likely- to occur during smolt migration with the result that the number of smolts reaching the sea would be between 39,000 and 44,000.

Trout - Salmo trutta

(a) Migratory Trout

Nine adults were found during the survey* This low figure may be due to the fact that the sections surveyed for juvenile fish were not suitable for adults

(b) Brown Trout

Since it was not possible to distinguish between parr of brown trout and migratory trout. Tables 7, 8 and 9 refer to parr of brown and migratory trout and adult brown trout.

In comparison with 1965 the average size of trout in the West and East Dart rivers appears to have declined, 1969 figures further show a more even distribution of both size and numbers of trout throughout the river system.

The rivers Harbourne, Mardle and Yeo are more productive of large trout than some of the moorland streams.

-8- The sizes of the trout caught in each section are given in Tables 7, 7 and 9.

D. DISCUSSION

During the planning of this survey it was felt desirable to change the location of certain sections to positions which were more typical of the length of river. Additional sections were included in areas which were considered to be under-surveyed.

In view of the increased number of sections surveyed, the method of Le Cren and Seber (1967) was used to estimate population densities. Test sections were fished using the traditional4 but more lengthy* method and later by the method of Le Cren and S liber. A good degree of concordance was found between the methods. Considerable time was saved in the whole survey by the use of Le Cren and Seber's method.

The high efficiency of the fishing teams is evidenced by comparison of the actual and calculated catch figures.

In terms of numbers of parr produced, the rivers West Dart, East Dart and the Middle Dart from Dartmeet to Buckfast contribute more than half of the parr production of the whole River Dart system.

The areas producing high densities of fish include the Cherry Brook, West Webburn river, East Webburn river, the Blackbrook river, the Walla Brook and the East Dart river.

The Blackbrook, Swincombe and the Harbourne rivers show a decrease in parr numbers compared with 1965 survey results. Increases in parr numbers were found in the Cherry Brook and the Ashburn. Caution should be exercised however in assessing the significance of changes in parr populations since:

1. The surveys are separated by four years.

2. Spawning stocks may differ as a result of disease or lack of penetration due to adverse water conditions.

3. Populations may vary not only annually but seasonally as a result of movement within the river system.

4. Changes may occur in the composition of the populations of competitor and predatory species.

A long-term experiment was begun in the autumn of 1969 to assess the required stocking density of the Walla Brook, A combined upstream barrier and downstream smolt trap was installed isolating about three miles of river. A continuing programme is proposed of removal of salmonids, stocking with feeding fry and population surveys.

It is considered that the population of salmon parr of the River Dart system is being maintained and that artificial seeding may enhance the natural seeding.

E. ACKNOWLEDGEMENTS

The co-operation is acknowledged of riparian owners who allowed survey work to be done on their waters.

-9- Mr. M.E. Wilson, Assistant Fisheries Officer, supervised the field work, Mrs. S. Ching, Mr. M.J. Chudley and Mr. J. Price prepared, analysed and presented the data. Their help is gratefully acknowledged.

Thanks are due to members of the bailiff service for their help in fishing the sections.

F. BIBLIOGRAPHY

Le Cren, E.D. & Seber, E.A.F. (1967) J. Anim. Ecol. 36 : 631 - 643.

Mann, K.H. (1967) The production of coarse fish in some southern chalkstreams. Proc. Third Brit. Coarse Fish Conf., Liverpool.

Nott, F »J. & Beale, P.B. (1965) River Dart Fisheries Survey, 1965.

Fisheries Dept., Devon River Authority, Exeter.

Southwood, T.R.E. (1966) Ecological Methods. Methren. London.

APPENDIX

Catches of salmon and migratory trout by nets and rods between 1959 and 1968

Salmon Migratory Trout Year Rods Nets Rods Nets

1959 275 875 1,421 568 1960 360 898 1,074 526 1961 150 1,018 1,300 659 1962 178 1,326 1,373 828 1963 321 1,643 1,247 849 1964 291 1,533 1,496 701 1965 366 1,640 1,462 696 1966 475 1,262 1,203 647 1967 340 1,188 926 670 1968 185 541 1,065 537 ......

Devon River Authority, F.J. NOTT County Hall, Fisheries and Pollution Officer EXETER, Devon. TABLE 1 Totals of all Salmonid Fish found in each Section West Dart River and Tributaries

Name of Section Trout Salmon Parr Migratory Trout Salmon Totals All Fish Blackbrook River A.384 Road Bridge 85 34 119 Cairns Bridge 77 54 - 131

162 88 -> 250 Cowsic River Beardown Farm 93 3 _. 96 93 3 - _ 96 Cherry Brook, u/s Powder Mill 55 22 77 d/s Powder Mill 37 31 - 68 Cherry Brook Bridge 95 59 _ - 154 187 112 _ =, 299

West Dart River Crockern Tor 77 29 106 Two Bridges 60 15 _ 75 Prince Hall 76 61 - 137 u/s Swincombe Foot 34 104 _ 138 Huccaby 36 25 _ - 61

283 234 __ 517

Swincombe River u/s Water Intake 43 21 64 Swincombe Farm 68 53 _- 121 Sherberton Farm 22 20 _ 42 ... 133 93 _ 227 TABLE 2 Totals of all Salmonid Fish found in each Section - East Dart River and Walla Brook

Name of Section Trout Salmon Parr Migratory Trout Salmon - Totals All Fish

East Dart River Hartland Tor 38 61 - - 99 Postbridge 75 159 - - 234 Believer 31 160 -- 191 Laughter Hole 16 41 - - 57 Brimps Farm 18 19 2 5 42

178 150 2 5 623

Walla Brook Stats Bridge 43 --- 43 Pizwell 182 39 - - 221 Runnage Bridge 111 21 - - 132 Riddon Farm 25 5 - - 30 Sherril 55 58 - - 113

416 123 - - 539 TABLE 3 Totals of all Salmonid Fish found in each Section - River Dart and Tributaries d/s Dartmeet

Name of Section Trout Salmon Parr Migratory Trout Salmon Totals All Fish River Dart Dartmeet 21 32 - - 53 New Bridge 5 39 - _ 44 26 60 1 » 87 Queen of the Dart 25 149 - - 174 Austins Bridge 25 29 - - 54 Staverton 11 4 1 - 16 113 313 2 - 428

West Webburn Grendon Bridge 88 25 - - 113 Cator Bridge 44 38 - - 82 Shallowford Bridge 68 59 - - 127 Pondsworthy 51 18 1 - 70 251 140 1 - 392

East Webburn Bag Park Bridge 83 6 - - 89 Widecombe Bridge 70 37 - - 107 Cockingford Bridge 31 35 - - 66 184 78 - - 262 River Webburn Lower Lodge Bridge 37 46 1 - 84 37 46 1 - 84

Holy Brook Hawson Court 39 1 - - 40 39 1 40 - Contd,. TABLE 3 - contcL

j Name of Section Trout Salmon Parr Migratory Trout Salmon Totals All Fish

River Yeo Rew 42 42 Pridhamsleigh Bridge 24 10 34 66 10 76

River Mardle Bilberry Hill 129 129 129 _ _ - 129

River Hems Bow Bridge 24 -- - 24 Littlehempston 43 28 1 72

67 28 1 _ 96

River Harbourne Yeo Bridge 58 12 _ - 70 Roister 36 8. 1 - 45 Crowdy Mill 37 8 1 - 46

131 28 2 161 TABLE 4 Salmon West Dart and Tributaries TABLE 5 Salmon East Dart and Walla Brook

| ^ ' ' \ ^ ^ ! 3 i z e in cms

Name

Easto f S e Dart c tio n River Hartland Tor P o s tb r id g e B e lie v e r Laughter Hole Brimpts Farm

Walla Brook Stats Bridge

P iz w e ll Runnage Bridge

Riddon Farm S h e r r i 1 TABLE 6 Salmon - River Dart and Tributaries d/s Dartmeet

Size in cms

Name of Section River Dart Dartmeet

New Bridge Holne Bridge

Queen of the Dart

Austins Bridge

Staverton

West Webburn Grendon Bridge Cator Bridge Shallowford B»

East Webburn Bag Park Bridge

Widecombe Bridge Cockingford Bridge

River Webburn Lower Lodge Bridge

Holy Brook Hawson Court TABLE 6 - contd. TABLE 7 Trout - West Dart and Tributaries TABLE 8 Trout - East Dart and Walla Brook

Size in cms I Name of Section

East Dart River

Hartland Tor

Postbridge s i Believer

Laughter Hole Brimpts Farm

Walla Brook

Stats Bridge

* Pizwell

Runnage Bridge

Riddon Farm

Sherri1

* This section is in the Walla Brook experimental area and was therefore completely fished out. TABLE 9 - T ro u t - River Dart and Tributaries d/s Dartmeet

R iv e r D a rt D artm eet New B rid g e Holne Bridge

Queen of the Dart

Austins Bridge

S ta v e r to n

------West Webburn— Grendon Bridge Cator Bridge Shallowford B. Pondsworthy

East Webburn Bag Park Bridge

Widecombe Bridge Cockingford ”

River Webburn Lower Lodge Bridge

H oly B rook Hawson Court

C o n td . TABLE 9 - contd* TABLE 10 Population Densities of Salmonids - West Dart River and Tributaries * Including Migratory Trout and Adult Salmon (Refer to Table 1) •jj* Number Number Number Area of Section j No- Sq.m. No. Trout per No. Salmon per No. Fish per Section of of of (in sq.metres) per Fish * 100 sq.m. 100 sq.m. 100 sq.m. Trout Salmon Fish *

Blackbrook River A„384 Road Bridge 93 36 129 426 3.3 21.6 8.4 30.0 Cairns Bridge 100 70 170 585 3.4 17.9 12.5 30.4

Cowsic River Beardown Farm 93 3 96 502 5.2 18.6 0.6 19.2

Cherry Brook u/s Powder Mill 56 22 78 209 2.7 26.7 10.5 37.2 d/s Powder Mill 48 40 88 418 4.8 11.4 9.5 20.9 Cherry Brook Bridge 112 70 182 418 2.3 26.7 16.7 43.4

West Dart River Crockern Tor 77 30 107 368 3.4 20.8 8.1 28.9 Two Bridges 69 17 86 1,184 13.8 5.8 1.4 7.2 Prince Hall 82 66 148 946 6.4 8.6 6.9 15.5 u/s Swincombe Foot 40 124 164 1,062 6.5 3.8 11.7 15.5 Huccaby 52 36 88 689 7.8 7.5 5.2 12.7

Swincombe River u/s Water Intake 45 22 67 481 7.1 9.4 4.5 13.9 Swincombe Farm 85 67 152 669 4.4 12.7 10.0 22.7 Sherberton Farm 27 25 52 502 9.6 5.4 5.0 10.4 TABLE 11 Population Densities of Salmonids ° East Dart River and Walla Brook * Including Migratory Trout and Adult Salmon (Refer to Table 2)

.— ■ ' - ■■ Number Number Number Area of Section No. Sq.m, j No. Trout per No. Salmon per No. Fish^per Section of of of (in sq.metres) per Fish * j 100 sq.m. 100 sq.m. 100 sq.m. Trout Salmon Fish *

East Dart River Hartland Tor 39 63 102 281 2.8 13.9 22.5 36.4 Postbridge 85 179 264 803 3.0 10.6 22.4 33.0 Believer 49 255 304 455 1.5 10.7 55.4 66.1 Laughter Hole 18 46 64 555 8.7 3.2 8.2 11.4 Brimps Farm 28 29 64 828 12.9 3.4 3.5 7.7

Walla Brook Stats Bridge 43 - 43 84 1.9 53.7 - 53.7 Pizwell 175 37 212 293 1.4 60.3 12.8 73.1 Runnage Bridge 111 21 132 251 1.9 44.4 8.4 52.8 Riddon Farm 25 5 30 167 5.6 14.7 2.9 17.6 Sherril 136 314 2.3 21.3 22.6 43.9 70 66 TABLE 12 Population Densities of Salmonids - River Dart and Tributaries d/s Dartmeet * Including Migratory Trout and Adult Salmon (Refer to Table 3)

i Number Number Number Area of Section No. sq.m. I No. Trout per No. Salmon per No. Fish* per Section of of of (in sq.metres) per Fish * 100 sq.m. 100 sq.m. 100 sq.m. Trout Salmon Fish * River Dart Dartmeet 29 43 72 1 9129 15.7 2.6 3.8 6.4 New Bridge 5 40 45 428 9.5 1.2 9.5 10.8 Holne Bridge 31 73 104 1,311 12.6 2.4 5.6 8.0 Queen of the Dart 28 166 194 1,484 7.6 1.9 11.5 13.4 Austins Bridge 25 29 54 615 11.4 4.1 4.8 8.9 Staverton 12 4 17 1,171 68.8 1.0 0.3 1.5

West Webburn Grendon Bridge 90 40 130 334 2.6 27.3 12.1 39.4 Cator Bridge 62 53 115 385 3.4 16.3 13.9 30.2 Sha,Howford Bridge 68 59 127 477 3.8 14.2 12.3 26.5 Pondsworthy 58 20 79 396 5.0 14.5 5.0 19.8

East Webburn Bag Park Bridge 84 7 91 251 2.8 33.6 2.8 36.4 Widecombe Bridge 70 37 107 205 1.9 35.0 18.5 53.5 Cockingford Bridge 31 35 66 397 6.0 7.5 8.7 16.2

River Webburn Lower Lodge Bridge 50 62 113 468 4.1 10.6 13.2 24.0

Hawson Court 40 1 41 180 4.4 22.2 0.6 22.8

River Yeo Rew 48 - 48 250 5.2 19.2 _ 19.2 Pridhamsleigh Bridge 24 10 ! 34 | 209 6.2 12.0 5.0 17.0

Contd. TABLE 12 - contda

River Hems Bow Bridge Littlehempston

River Harbourne Yeo Bridge 58 12 70 418 Roister 36 8 44 460 Crowdy Mill 53 11 64 502