Fisheries survey report of the River Great Ouse: Brackley to Newport Pagnell 30th of July to the 20th August 2013 SUMMARY

The 2013 survey cycle recorded a number of exceptional specimen fish and some strong, if localised, roach populations were also found. The increased population of silver fish has meant that stock density has improved at most locations since the previous survey cycle. Perhaps unsurprisingly catches were linked to habitat quality with those sites offering riffle and pool habitat such as Manor Farm, Mill Farm Gayhurst and Wolverton Mill offering the greater catches of rheophillic (flow loving) species such as dace, chub and barbel. The slower glide and slack reaches produced stronger roach catches and occasional common bream. Standing crop has decreased at some locations due to the absence of large common bream found in 2010 and fewer chub being recorded at some sites.

RESULTS

Seventeen species and one hybrid were recorded over the ten sites sampled.

List of species caught: Roach [Rutilus rutilus] Spined loach [Cobitis taenia] Gudgeon [Gobio gobio] Barbel [Barbus barbus] Dace [Leuciscus leuciscus] Roach x common bream hybrid [Rutilus rutilus x Abramis brama] Perch [Perca fluviatilis] Brown / sea trout [Salmo trutta] Bullhead [Cottus gobio] Ruffe [Gymnocephalus cernuus] Minnow [Phoxinus phoxinus] 3-spined stickleback [Gasterosteus aculeatus] Chub [Leuciscus cephalus] Tench [Tinca tinca] Pike [Esox lucius] Brook lamprey [Lampetra planeri] Stone loach [Barbatula barbatula] Common bream [Abramis brama]

Density and standing crop pie charts with % values and colour key

Species composition by density of fish >99mm Species composition by standing crop of fish >99mm

The average density (number of fish in a given area) of all species (>99mm) over all sites equates to 12.2 Ind./100m2 Total average standing crop (weight of fish in a given area) of all species (>99mm) over all sites equates to 1102 g/100m2.

The largest fish recorded during the survey included a barbel of 730 mm (13lb) from Mill Farm Gayhurst and a chub of 534mm (6lb 8oz) from Manor Farm.

The largest individual (mm) and estimated number of fish (>99mm) are recorded for barbel, chub, perch and roach at site level (Table 1).

Table 1: Numbers recorded (all fish) and largest length (mm) for selected species.

Trout Chub Roach Dace Barbel Largest Largest Largest Largest Largest No. (All) No. (All) No. (All) No. (All) No. (All) Site (mm) (mm) (mm) (mm) (mm) Westbury 3 416 16 415 35 238 29 242 - - Buckingham - - 2 146 300 279 25 191 - - Thornborough Mill - - 6 162 67 170 6 162 - - Mount Mill Farm - - 2 198 11 176 14 181 - - D/s Mill Farm - - 5 477 45 210 5 162 - - Passenham - - 1 94 431 200 34 202 - - Old Stratford - - 7 117 327 184 33 173 - - D/s Wolverton Mill - - 17 530 154 259 114 200 1 168 Manor Farm - - 30 534 58 186 40 204 7 677 Mill Farm Gayhurst* - - 11 478 49 173 9 163 6 704 *Single catch minimum estimate

Table 2: Survey Sites

Survey Site Name Reference Date Grid reference Catch Strategy Catch Method Area (M2) Westbury 4622 07/08/2013 1110 SP6216435534 CATCH DEPLETION ELECTRIC FISHING Buckingham 4625 08/08/2013 1020 SP6985833956 CATCH DEPLETION ELECTRIC FISHING Thornborough Mill 4627 14/08/2013 1650 SP7368835432 CATCH DEPLETION ELECTRIC FISHING Mount Mill Farm 4628 05/08/2013 1400 SP7628937592 CATCH DEPLETION ELECTRIC FISHING D/s Mill Farm 4630 13/08/2013 2250 SP7743338410 CATCH DEPLETION ELECTRIC FISHING Passenham 4631 02/08/2013 960 SP7838639304 CATCH DEPLETION SEINE NETTING Old Stratford 4633 30/07/2013 1040 SP7815040692 CATCH DEPLETION SEINE NETTING D/s Wolverton Mill 4635 20/08/2013 1750 SP7973241309 CATCH DEPLETION ELECTRIC FISHING Manor Farm 36762 06/08/2013 1845 SP8079742435 CATCH DEPLETION ELECTRIC FISHING Mill Farm Gayhurst 4637 31/07/2013 2000 SP8562445154 SINGLE CATCH ELECTRIC FISHING

INTRODUCTION TO ENVIRONMENT AGENCY FISHERIES SURVEYS :

The Environment Agency has a statutory duty to maintain, improve and develop fisheries. Our policy is to do this in a way that maximises the social, recreational and economic benefits arising from the sustainable exploitation of the fish stocks that underpin fisheries. To help deliver this duty, we have a National Fisheries Monitoring Programme (NFMP) to describe the status of our fish populations and inform our fisheries management to meet international, national and local data needs. Sites are regularly reviewed to maintain a representative sample of fish populations and the water body as a whole in order to retain a comparable dataset. Sites designated for the national fisheries monitoring programme cannot be altered, unless there is a valid health and safety concern or there has been a review of policy during the monitoring period.

METHODOLGY:

Ten sites were surveyed on the river Great Ouse between the 30th of July and the 20th of August 2013. The sites were sampled using a combination of electric fishing and drag down seine netting methodology depending on the nature of the site.

Electric fishing: This survey technique uses the physiological effect of an electric field in water to attract and immobilise fish. Electrodes, immersed in the water, stimulate a fishes nervous system so that it swims towards the operator, or is unable to swim away, and can be caught. Image 1 shows the typical components of an electric fishing system. In shallow streams it is generally possible to wade upstream within the channel using generator powered equipment towed within a small boat, (Image 1). When rivers deepen or site depth is variable, electric fishing from a boat using generator powered equipment is often the preferred method. The boat is manoeuvred downstream on ropes by an operative on either bank controlling the speed, direction and channel positioning. Stop nets are positioned across the channel isolating the survey site preventing fish from migrating Image 1. into and out of the survey area. The electric fishing operation is repeated until a 50% reduction in the total number of fish caught has been achieved (catch depletion).

Seine netting: Stop nets are positioned across the channel to isolate the survey site and prevent fish from migrating into and out of the survey area (seine 3 & 4 on image 3 below). A catching net is set at the lowermost extent of the survey site (seine 2) and a heavily weighted net is then laid across the channel (seine 1) which is drawn downstream driving fish into the catching net. The catching net is drawn into the bank to encircle the driving seine which is then removed. Fish are then trapped within the catching net which may be hauled in. The netting operation is repeated until a 50% reduction in the total number of fish caught has been achieved. The nets are constructed from 10mm knotless mesh which is relatively soft and helps to minimize fish damage. Floats are attached along the top edge and a lead-line along the bottom edge so that the net hangs vertically within the water column.

Image 3.

Fish captured by both techniques are measured to the nearest millimetre and scale samples are taken for age and growth analysis. Results are reported primarily utilising fish greater than 99mm as both methods have been shown to lose efficiency on fish below this length. Supporting evidence is also presented using total catch figures i.e. fish of all lengths. These figures are likely to be an underrepresentation of stock and where included should be viewed with caution.

COMBINED SURVEY RESULTS

The average density (number of fish in a given area) of all species (>99mm) over all sites equates to 12.2 Ind./100m2 Total average standing crop (weight of fish in a given area) of all species (>99mm) over all sites equates to 1102 g/100m2. Roach were the most common fish (>99mm) over the ten sites surveyed with a mean density estimate of 6.1 individuals for every 100m2 of river surveyed, or a 50 % share of the population. Dace populations were subdominant representing a 21% share of the total population with an estimated mean density of 2.5ind./100m2.

Figure 1. Mean density of fish (>99mm) in the River Great Ouse 2013 (Mill Farm excluded)

Chub were the dominant species’ by weight with a mean standing crop estimate of 317.8 g/100m2 and representing 29% of the total weight of fish captured. Roach populations were subdominant by weight at 281.7 g/100m2 (26% of standing crop), Pike were the third most important species with an estimated 209.1g/100m2 representing a 19% share of the total weight of fish caught, the comparatively low numbers caught does not point to a predator prey imbalance.

Figure 1a. Mean standing crop of fish (>99mm) from the River Great Ouse 2013 (Mill Farm data excluded)

Figure 2: Density of species >99mm at site level 2013

Figure 2 shows the numerical prevalence of roach which were generally either the dominant or the subdominant species at each site sampled, the notable exceptions to this being the Mount Mill Farm and Manor Farm sites. Site 4631 (Passenham) provided the highest density recorded with a population estimate of 29.4 ind./100m2 which was chiefly comprised of roach. Figure 2a indicates the importance of chub and roach to the overall standing crop estimate, the capture of large barbel at Manor Farm is also apparent.

Figure 2a: Standing crop of species >99mm at site level 2013

SITE LEVEL DATA

Site No. 4622: Westbury

Species present (All lengths) Species Number Species Number Bullhead [Cottus gobio] 59 Perch [Perca fluviatilis] 12 Roach [Rutilus rutilus] 35 Stone loach [Barbatula barbatula] 4 Dace [Leuciscus leuciscus] 29 Brown / sea trout [Salmo trutta] 3 Chub [Leuciscus cephalus] 16 Gudgeon [Gobio gobio] 3 Minnow [Phoxinus phoxinus] 16 3-spined stickleback [Gasterosteus aculeatus] 2

Population Composition Density (Lengths >99mm) In 2013 the fish population at Westbury was dominated by roach and dace. Fish densities have decreased since the previous survey in 2008 however stocks currently remain more diverse and numerous than recorded in the three preceding historic surveys conducted at this location in 1991, 1994 and 1997.

Density estimate (>99mm) at Westbury 1991 – 2013

Site No. 4625: Buckingham

Species present (All lengths) Species Number Species Number Roach [Rutilus rutilus] 300 Pike [Esox lucius] 14 Bullhead [Cottus gobio] 74 Gudgeon [Gobio gobio] 11 Dace [Leuciscus leuciscus] 25 Chub [Leuciscus cephalus] 2 Minnow [Phoxinus phoxinus] 17 Perch [Perca fluviatilis] 1

Population Composition Density Fish populations at Buckingham are (Lengths >99mm) dominated numerically by roach and dace. Roach have shown a considerable increase at this location over the past two surveys, the species being poorly represented during the seven surveys conducted at this location between 2003 and 2009. The 2013 survey also saw an increase in dace density recorded. Occasional catches of chub have been made at this site with populations highest in 2004 and 2008 however this has generally consisted of a small number of large individuals. The 2013 survey found only two chub present, both small fish of around 3 years of age.

Density estimate (>99mm) at Buckingham 1988 – 2013

Site No. 4627: Thornborough

Species present (All lengths) Species Number Species Number Roach [Rutilus rutilus] 67 Common bream [Abramis brama] 2 Gudgeon [Gobio gobio] 61 Minnow [Phoxinus phoxinus] 2 Perch [Perca fluviatilis] 18 Brook lamprey [Lampetra planeri] 1 Chub [Leuciscus cephalus] 6 Bullhead [Cottus gobio] 1 Dace [Leuciscus leuciscus] 6 Ruffe [Gymnocephalus cernuus] 1 Pike [Esox lucius] 5 Stone loach [Barbatula barbatula] 1 Spined loach [Cobitis taenia] 3 Tench [Tinca tinca] 1

Population Composition Density (Lengths >99mm) Fish densities at Thornborough have increased since the previous survey in 2010 with larger populations of gudgeon and roach recorded. Roach populations at this site seem to show considerable variance over successive survey cycles. The estimated standing crop at this site has fallen since 2010, primarily due to the absence of a small shoal of large common bream captured in 2010. Common bream remained present at this location in 2013 but were represented by a small number of juvenile fish.

Density estimate (>99mm) at Thornborough 1988 – 2013

Site No. 4628: Mount Mill Farm

Species present (All lengths) Species Number Species Number Minnow [Phoxinus phoxinus] 47 Pike [Esox lucius] 4 Dace [Leuciscus leuciscus] 14 Chub [Leuciscus cephalus] 2 Bullhead [Cottus gobio] 12 Stone loach [Barbatula barbatula] 1 Roach [Rutilus rutilus] 11 Tench [Tinca tinca] 1 Gudgeon [Gobio gobio] 6

Population Composition Density Since the late 1990’s this site has been typified (Lengths >99mm) by a low fish population density. The most

consistent stock has been composed of a

number of mature chub located around the

riffle and small area of riparian tree cover

present. These large fish were absent during

the 2013 survey cycle with only two fish of

younger year classes present. It should be

noted that the 2013 survey was affected by

low river levels and the channel in the vicinity

of the riffle and overhanging tree was of

insufficient depth to support a population of

large chub, suggesting that these fish have

moved elsewhere. A small number of roach

and dace were present in 2013, with dace

currently dominant by density.

Density estimate (>99mm) at Mount Mill Farm 1988 – 2013

Site No. 4630: D/s Mill Farm

Species present (All lengths) Species Number Species Number Roach [Rutilus rutilus] 45 Chub [Leuciscus cephalus] 5 Minnow [Phoxinus phoxinus] 31 Dace [Leuciscus leuciscus] 5 Bullhead [Cottus gobio] 14 Gudgeon [Gobio gobio] 3 Pike [Esox lucius] 14 Perch [Perca fluviatilis] 1 Stone loach [Barbatula barbatula] 13 Spined loach [Cobitis taenia] 1

Population Composition Density (Lengths >99mm) With the exception of the 1993 dataset Site 4630 had maintained a fairly consistent roach population. This ceased in the late 1990’s when the species were replaced by a population of chub which was primarily composed of large individuals. The 2013 survey cycle found fewer chub present and that roach had returned, although in lesser numbers than has been found during historic surveys. The chub which remained present in 2013 were all large specimens >400mm in length with no representation from younger year classes found.

Density estimate (>99mm) at DS Mill Farm 1988 – 2013

Site No. 4631: Passenham

Species present (All lengths) Species Number Species Number Roach [Rutilus rutilus] 431 Bullhead [Cottus gobio] 1 Gudgeon [Gobio gobio] 133 Chub [Leuciscus cephalus] 1 Perch [Perca fluviatilis] 43 Common bream [Abramis brama] 1 Dace [Leuciscus leuciscus] 34 Ruffe [Gymnocephalus cernuus] 1 Pike [Esox lucius] 5 Spined loach [Cobitis taenia] 1

Population Composition Density (Lengths >99mm) Roach populations at Passenham were much improved on the 2010 survey cycle with >400 individuals recorded. Long term data indicates roach populations at this site are likely to be influenced by stock migration and environmental conditions.

The habitat within this survey site is rather limited with a lack of overhead cover and catches at this location are often heavily influenced by the turbidity of the river at the time of sampling; if there is colour in the water then there is potential for a large catch, conversely, if the river is running clear then the likelihood is that the catch will be poor. This suggests that the limited habitat and lack of cover in the immediate vicinity of the survey area is influencing fish distribution, with fish less likely to utilise this section of channel during clear water conditions.

Density estimate (>99mm) at Passenham 1988 – 2013

Site No. 4633: Old Stratford

Species present (All lengths) Species Number Species Number Roach [Rutilus rutilus] 327 Common bream [Abramis brama] 19 Gudgeon [Gobio gobio] 76 Chub [Leuciscus cephalus] 7 Perch [Perca fluviatilis] 62 Pike [Esox lucius] 3 Dace [Leuciscus leuciscus] 33 Ruffe [Gymnocephalus cernuus] 1 Also present: Roach x C bream hybrid 4

Population Composition Density Fish population density at Old Stratford (Lengths >99mm) remains comparable to the previous survey

conducted in 2008 however species

composition has changed slightly with

increased representation from dace stocks and

a small number of chub from younger year

classes recorded in 2013.

The standing crop estimate at this location has decreased due to the absence of large common bream (and a single common carp) recorded in 2008. Common bream remained present in 2013 but were represented by younger year classes.

#

Density estimate (>99mm) at Old Stratford 1988 – 2013

Site No. 4635: D/s Wolverton Mill

Species present (All lengths) Species No. Species No. Roach [Rutilus rutilus] 154 Spined loach [Cobitis taenia] 10 Dace [Leuciscus leuciscus] 114 Minnow [Phoxinus phoxinus] 5 Perch [Perca fluviatilis] 49 Gudgeon [Gobio gobio] 4 Pike [Esox lucius] 18 Bullhead [Cottus gobio] 1 Chub [Leuciscus cephalus] 17 Common bream [Abramis brama] 1 Stone loach [Barbatula barbatula] 11 Barbel [Barbus barbus] 1

Population Composition Density In terms of fish >99mm dace and roach (Lengths >99mm) density was comparable, although in terms of total catch roach were slightly more numerous. This site produced the largest catch of dace made during the 2013 survey cycle on the Great Ouse and contained individuals to 200 mm in length.

Although only representing 6% of population density chub the major component of standing crop with a 29% share recorded. The chub population was composed of 17 fish which between 106mm and 530 mm in length. A single barbel of 160mm was also recorded at this site.

This is a new site. No historic data currently available.

Site No. 36762: Manor Farm

Species present (All lengths) Species Number Species Number Roach [Rutilus rutilus] 58 Gudgeon [Gobio gobio] 18 Dace [Leuciscus leuciscus] 40 Pike [Esox lucius] 11 Chub [Leuciscus cephalus] 30 Barbel [Barbus barbus] 7 Perch [Perca fluviatilis] 29 Bullhead [Cottus gobio] 2 Minnow [Phoxinus phoxinus] 19 Stone loach [Barbatula barbatula] 1

Population Composition Density The fish population at manor farm has increased (Lengths >99mm) when compared to previous survey cycles in 2004 and 2008 datasets but are density remains lower than historic surveys conducted in 1999-1997 due to fewer roach, dace and gudgeon. Chub density has remained broadly comparable throughout all six survey cycles.

The catch made in 2013 included two chub over 6lb and barbel of 11lb and 9lb. Representation from juvenile fish of both species was also noted with five barbel between 140mm and 174 mm and ten chub between 127mm and 194 mm recorded. A total of 30 chub were caught at this location with seventeen of these fish measuring over 400 mm in length. The inclusion of 11 pike at this location may appear quite high however over 50% of these fish were small individuals of 20cm and below; one large fish of 865mm was also recorded.

Density estimate (>99mm) at Manor Farm 1988 – 2013

Site No. 4537: Mill Farm Gayhurst

Species present (All lengths) Species Number Species Number Minnow [Phoxinus phoxinus] 53 Gudgeon [Gobio gobio] 8 Roach [Rutilus rutilus] 49 Barbel [Barbus barbus] 6 Perch [Perca fluviatilis] 14 Bleak [Alburnus alburnus] 2 Chub [Leuciscus cephalus] 11 Pike [Esox lucius] 1 Dace [Leuciscus leuciscus] 9 Stone loach [Barbatula barbatula] 1

Population Composition Density The population density at Mill Farm Gayhurst was (Lengths >99mm) lower than recorded in 2011 however the two surveys are not directly comparable; the 2013 survey being undertaken using single catch methodology due to torrential rain which moved in half-way through the survey. To wait for the rain to clear may have caused undue stress on the large fish captured and retained for processing. The 2013 survey result should therefore be viewed as a minimum estimate of stock present.

Despite the single catch methodology used the 2013 result remains much improved on the 2003- 2005 survey cycles and roach remained dominant by density. Barbel were primary by standing crop with a 54% share of biomass recorded. A total of 6 barbel were captured with a maximum length of 737mm (weighing 13lb) four of the fish were >500mm in length and two juvenile fish were also recorded. The current density estimate for barbel at this site is 0.3 Ind/100m2, broadly similar to the long term mean of 0.37 Ind./100m2. See graph overleaf.

Density estimate (>99mm) at Mill Farm Gayhurst 1994 – 2013

Barbel density estimate (>99mm) at Mill Farm Gayhurst 1988 – 2013

CONCLUSIONS

The 2013 survey cycle recorded a number of exceptional specimen fish and some strong, if localised, roach populations were also found. The increased population of silver fish has meant that stock density has improved at most locations since the previous survey in 2010. Perhaps unsurprisingly catches were linked to habitat quality with those sites offering riffle and pool habitat such as Manor Farm, Mill Farm Gayhurst and Wolverton Mill offering the greater catches of rheophillic (flow loving) species such as dace, chub and barbel. The slower glide and slack reaches produced stronger roach catches and occasional common bream. See the following habitat spreadsheet (Table 3) for more information.

Standing crop has decreased at some locations due to the absence of large common bream found in 2010 and fewer chub at some survey locations.

Length frequency data derived from these surveys shows poor representation by the younger year classes of a number of gravel spawning species suggesting that spawning success may be a bottleneck limiting these species populations. Dace populations seem to show a distinct missing year class with an absence of fish between 60mm and 80 mm. Standard growth would suggest that these fish would be around 1 year old potentially indicating that the drought period of 2011-12 influenced the spawning success of this species, potentially due to increased siltation and compaction of spawning riffles.

Missing year class

Dace Length Frequency from the 2013 Survey Cycle

The influence of sediment and river flow has been covered in previous Great Ouse report; in brief, high levels of sediment within the river can lead to vital riffle areas becoming choked with sand and fine silt particles meaning spawning success will be reduced and an increased mortality rate will occur amongst eggs and fish larvae which do not receive a sufficient through-flow of aerated water.

Work undertaken to assess the success of barbel spawning found that a number of riffles on the Great Ouse were compacted and contained high levels of sediment. It was felt that this may have been sufficient to indicate a population bottleneck for this gravel spawning species. In an effort to remediate siltation a number of gravel riffles are now being cleansed by jetting and this has been undertaken yearly at a number of sites which have been selected in association with local anglers who have provided valuable information on spawning locations. Some riffles that initially seemed quite acceptable as spawning media were subsequently discovered quite unsuitable being composed of shallow gravel overlaying either a coarse rubble or sandy matrix. Four such riffles have subsequently been redressed with a new gravel substrate. Gravel jetting operations have now been conducted since February 2008, a total of nine sites have been cleaned, with some locations subject to repeated operations. Spawning barbel have been observed utilising these cleansed riffles and it is hoped that this work has helped improved egg and larvae survival for this and other gravel spawning species.

Chub Length Frequency from the 2013 Survey Cycle

Chub show similarly poor representation by younger year classes suggesting this gravel spawning species is also suffering from poor recruitment. The reduction of silt influx into the Ouse will therefore be advantageous for widespread and long term improvements in the populations of dace and other gravel spawning species. Information of completed projects and planned projects to tackle this issue follow.

HABITAT WORK

COMPLETED

Gravel redressing October 2013 – Gravel redressing conducted on a historic spawning riffle at Adams Mill by staff from the F&B (fisheries and biodiversity) team. The addition of 7 tonnes of 10-40 mm washed gravel will improve the spawning substrate primarily for resident barbel & chub however other gravel spawning species, such as dace, will also benefit from this work.

Tree planting March 2014 – Tree planting of 60 willow whips on the river bank by F&B staff to provide overhanging tree cover for fish and other wildlife in future years. Many old willows have disappeared over the years through a combination of natural erosion and erosion caused by signal crayfish burrowing activities so this work will help replace this important habitat.

Stony Stratford sluice bank repairs - Fisheries & Biodiversity, Operations, Milton Keynes Park’s Trust and volunteers worked together to repair a section of eroded bank on the Great Ouse at Stony Stratford. Using soft engineering in the form of willow bundle revetments to reinforce and protect a section of bank that had become eroded as a result of livestock poaching and flow pressures from Stony Sluice. Not only have the works provided instant marginal habitat that was previously missing, but as the ‘live’ willow grows, it will further stabilize the banks and prevent erosion, siltation and degradation of river habitats. Having acquired these new skills, Milton Keynes Park’s Trust and their volunteers are confident they can apply them to other similar types of erosion within the MK Ouse and Ouzel, some of which have been identified in the water body action plans. With these keen stake holders on board, we are confident significant improvements can be made to river habitat quality in Milton Keynes over the next few years.

Bank erosion protection and habitat enhancement Fisheries & Biodiversity (F&B) officers Rob Clapham and Paul Wilkanowski represented the Environment Agency at a Wild Trout Trust / River Restoration Centre development day, providing hands-on help and advice. The group used locally sourced Willow and Hawthorn to protect two sections of eroding bank on the Great Ouse at Water Stratford. This demonstrates a cheap, effective way of protecting banks using non-skilled volunteers. The end result is instant improvement in habitat for fish and invertebrates and a bank that is expected to further stabilize as it accumulates sediment. The day also demonstrates how we might use such events in the future to educate and engage local groups and land owners. F&B plans to undertake similar works with Operations Delivery team members in spring, before working with local stakeholders to tackle similar erosion issues throughout the Upper Ouse catchment.

IN PROGRESS

 Plans to tackle fish passage in the upper Ouse from Wolverton to Thornborough

 Deliver mitigation measures in upper Ouse

 More tree planting (ideally with angling club participation) to improve habitat.

 More gravel jetting (ideally with angling club participation) to clean spawning gravels.

 Opening up backwaters to provide off river refuge.

 Tackling catchment scale sediment issues to improve habitat and spawning success.

If any angling matches are held throughout this river length then angling clubs are encouraged to provide match results to feed into the Environment Agencies Match Catch Database which analyses angler catches to assess fishery performance. The output of this database can also be used as supporting evidence to assist analysis of routine survey results. Match return cards and more information on the Match Catch Database can be obtained from Fisheries Analysis and Reporting Officer Chris Middleton [email protected]

The Great Ouse between Brackley and Newport Pagnell will next be surveyed in 2016. TABLE 3: HABITAT DATA FROM SITES SURVEYED 2013

Channel Margins Substrate % (approx) Habitat Site Name Av. Width (m) Av. Depth (cm) 1 2 3 Cobbles Gravel Sand Silt Clay 1 2 3 4

Westbury 4 70 Shallow Steep Natural 15 60 - 25 - Glide Run Pool -

Buckingham 12 60 Shallow Natural - 40 20 - 40 - Glide - - -

Thornborough Mill 14 70 Shallow Steep Natural 10 60 - 30 - Glide Slack - -

Mount Mill Farm 12 100 Steep Shallow Natural _ 30 _ 70 - Run Glide Slack -

D/s Mill Farm 12 80 Steep Shallow Natural 40 40 15 5 - Glide Run - -

Passenham 12 200 Steep _ _ _ 70 _ 30 _ Glide - _ _

Old Stratford 16 250 Steep Natural - _ _ _ 70 30 Glide - - -

D/s Wolverton Mill 10 120 Steep Natural Shallow 80 10 10 Riffle Pool Run Glide

Manor Farm 9 100 Steep Natural - - 80 10 10 - Riffle Pool Run Glide

Mill Farm Gayhurst 8 125 Steep Shallow Natural 5 65 - 30 - Run Pool Riffle Glide

Algae Overhead Emergent Submerged Site Name Tree Roots Woody Debris Turbidity Land use cover Macrophytes Macrophytes Non Filamentous Filamentous Parkland/Pastu Westbury Extensive None Sparce Occasional Sparce Sparse None Moderate re

Buckingham Intermittent Rare Sparce None Sparce None None High Urban

Thornborough Mill Sparce Rare Occasional Sparse Sparce Sparse None Slight Pasture

Mount Mill Farm None None None Occasional Sparse Sparse None Slight Pasture

D/s Mill Farm Sparse Sparse None Occasional Sparse Occasional None Slight Pasture

Agricultural & Passenham Sparse None Sparse Sparse None Sparse None Moderate Pasture Pasture & Old Stratford Sparse Sparse Sparse Sparse Sparse Occasional None Moderate Parkland Pasture, D/s Wolverton Mill Sparse Sparse Sparse Abundant Occasional Sparse Sparse Slight Agricultural Agricultural & Manor Farm Sparse Occasional Sparse Occasional None None None Slight Caravan Park

Mill Farm Gayhurst Intermittent None Sparse Occasional Occasional Sparse None Slight Pasture Site 4630 D/s Mill Farm TABLE 4: BREAKDOWN OF CATCHES 2013

Previous Current Current Previous Current Number of Number of Most standing Crop Standing Crop Density Site Name N.G.R Date Density >99mm Density >99mm species species common Largest Fish Comments >99mm >99mm All Fish (Ind/100m2) (Ind/100m2) previously currently species (g/100m2) (g/100m2) (Ind/100m2)

42 cm Brown Fewer brown trout than recorded in Bullhead / Westbury SP6216435534 07/08/2013 1933 1408.0 23.78 9.91 17.66 10 10 Trout / 42 cm 2010. 21 dace to 24 cm also Roach (35) Chub present. Density estimate >99mm 53 cm pike / 28 comparable to previous survey cycle Buckingham SP6985833956 08/08/2013 2315.3 1354.3 14.51 14.61 46.67 8 8 Roach (300) cm roach however smaller average roach size in 2013. Decline in biomass due to absence Roach (50) / 56cm Pike / of large common bream in 2013 and Thornborough Mill SP7368835432 14/08/2013 1453.2 313.8 1.76 4.36 11.52 11 14 Gudgeon (44) 17cm Dace poor perch depletion in 2010 which overestimated population. A dissapointing catch but dace, Minnow / 47 cm Pike / roach and gudgeon population has Mount Mill Farm SP7628937592 05/08/2013 721.9 628.4 0.93 2.57 9.57 8 9 Dace (14) 19 cm Chub shown slight improvement since 2010. Roach numbers increased since D/s Mill Farm SP7743338410 13/08/2013 1720.267 673.0 1.69 2.98 6.84 12 10 Roach (33) 47 Cm Chub 2008, however fewer specimen chub present.

Good catch of over 400 roach. 20 cm Roach / Passenham SP7838639304 02/08/2013 173.8 983.0 1.46 29.48 70.21 6 10 Roach (431) Moderately turbid water during 20 cm Dace survey. Large common bream recorded in 28 Cm Perch / 2008 absent during 2013 although Old Stratford SP7815040692 30/07/2013 3164 509.0 17 16.54 51.83 9 9 Roach (327) 18 cm Roach / juvenile fish remain present. Density 17 cm Dace estimate comparable.

Roach (58) / 87 cm Pike / Chub of 6lb and 6lb 8oz. Barbel of Manor Farm SP8079742435 06/08/2013 2971.5 2735.6 2.76 8.94 12.85 8 10 Dace (40) 68 cm Barbel 11lb and 9lb 8oz

First survey at this location. Good Roach (154) / 73cm Pike / 53 D/s Wolverton Mill SP7973241309 20/08/2013 N/A 1677.2 N/A 20.51 25.31 N/A 12 catch of dace to 20 cm and roach to Dace (114) cm Chub 26cm. Juvenile barbel recorded.

Four Barbel largest 13lb and 7lb and Minnow / 73cm Barbel / Mill Farm Gayhurst SP8562445154 31/07/2013 829.5 1323.5 7.1 4.1 7.7 11 10 two juvenile barbel. Specimen Chub. Roach 48cm Chub Fewer roach than 2011 survey.

87 cm Pike / Mean 1698.1 1160.6 7.89 11.40 26.02 12 14 Roach 73 cm Barbel

11lb Barbel from Manor Farm

A 13lb Barbel caught during the 2013 survey cycle at Mill Farm Gayhurst

6b 8oz Chub from Manor Farm

Quality Chub from Wolverton Mill

Roach from Buckingham