Development of MORPH for the Burry Inlet 2000-01 and 2004-05 cockle fisheries K M Bowgen

2017

This chapter describes the development of an individual-based model to investigate the impacts on oystercatchers from shellfishing industries. Individual-based models (IBMs) have been successfully used in similar scenarios in the Burry Inlet, Three-Rivers and Exe (West et al., 2001, 2015; Stillman, 2009; Stillman, Goss-Custard and Wood, 2014) estuaries and their inclusion here reflects the confidence in the accuracy of their outputs. Changes to shellfishing quotas will impact on the behavioural responses of wading birds such as oystercatchers and by modelling responses to different Total Allowable Catches (TAC), we can use empirically observed data to validate our models with for accurate predictions. The IBM of the Burry Inlet has been developed using the highly flexible modelling platform “MORPH” which is fully described in Stillman 2008. The current model’s parameterisations are detailed in the following sections following the layout and schedule of MORPH models and follow on from the most recent oystercatcher and shellfish models developed in 2014 (Stillman, Goss-Custard and Wood, 2014).

The source of the parameter values used in this model are detailed in Appendix 1. The parameters for the Burry Inlet are given in West et al. 2001, 2003)

12.1 Burry Inlet model

The values for the IBM parameterisation of the Burry Inlet have been developed from two previous studies (Stewart, 2001; West et al., 2001, 2015). In addition the new IBM, updates have been made to the processes used in these older studies to match the current standards of IBMs and MORPH that new studies are using. IBMs developed using MORPH follow a predefined format that is set up to represent the Burry Inlet’s foragers and environs. This is divided into three entities that define the Global environment, the resource filled Patches that individuals can forage up and the Foragers themselves. Tables 12.1-12.8 detail the parameters per entity to correspond with the full descriptions below.

12.2 Global environment

The global environment defines the state variables that the model uses throughout its parameterisation and runs. For the Burry Inlet this entails simple mathematical equations to define Timesteps, Days and Time as well as links to variable files for Daylight, Tide Height and Temperature values.

The model runs for 5,088 hour long time steps to simulate a seven month winter period from 00:30 on 1st September 2000 through to 23:30 31st March the following year (212 days). Daylight is a binary

variable (0=night, 1=day) defined from hourly tables accessed from the US Naval Observatory website (http://aa.usno.navy.mil/data/docs/RS_OneYear.php) and read in from a variable file (.var). Tide heights (m Chart Datum) are also read in from a variable file and the hourly values for the tide at Burry Port (51° 41’N, 004° 15’W) were taken from a licenced copy of TideWizard (Smartcom Software, 2009) for 2000/2001. Temperature is based on a 50 year average from the Exe estuary for each time step of the model.

12.3 Patches

The Patches entity includes all available habitats that individuals can potentially visit and contain resources. In the Burry Inlet model two additional areas, Water and Land exist but are inaccessible to foragers and were programmed to mimic their namesakes in the visualisation window. Two refuge areas (termed “roosting areas” in this document) are available on the land, “Roosts” and “Home”, which are accessed by Oystercatchers and Fishermen respectively. These “safe” areas contain no hazards to the individual foragers, are unlinked to density dependent effects and provide a location to stay when individuals not foraging or no foraging habitat is available.

There are twenty forageable patches with energetic resources in the 2000-01 model of the Burry Inlet (Table 12.2). Nine cockle beds, five mussel beds and four mussel crumble beds have been parameterised per description in West et al. (2003). and two single field and upshore areas are also included as alternative foraging areas with arbitrary parameters. The shellfishing beds range from 14,5000m2 to 2,892,000m2 and are all accessible by oystercatchers. The proportion of each patch that is exposed (and thus available to forage upon) at any point in the tidal cycle is defined by a minimum and maximum shoreheight (m CD) for each patch (see Table 12.2) and these were taken from a LiDAR survey carried out in 2003 (Kenneth Pye Associates Ltd 2003). Whilst roosting areas are always available, the additional field patch can only be accessed in daylight whilst the upshore has its own minimum and maximum shoreheights and is exposed in line with the shellfishing patches.

12.3.1 Patch resources

Twenty two types of resource are included in the Burry Inlet model and each patch contains a set starting density per m2. Defined by prey type and size class (width = five mm), each patch’s resource density were obtained from a survey in 2000 and early 2001 and energy content is defined in grams of ash free dry mass (AFDM). All starting densities and energy contents are detailed in Tables 12.3 and 12.4. As arbitrary alternative areas, Field Prey and Upshore Prey are maintained at 100 items per m2 throughout the winter whilst Cockles experience a 30% decline in prey numbers until the end of the model and Mussels a 5% decline. This accounts for the observed decline in prey densities of each resource due to non-bird related mortality.

Energy densities are again an arbitrary 0.1 g AFDM for Field and Upshore Prey whilst cockle and mussels are specific to each patch location. Mussels AFDM values were taken for each patch per size

class whilst average AFDM per size class was initially only available for the complete range of cockle beds. Cockle AFDM value are known to increase proportionally down the shoreline with higher values or AFDM at the lowest limits compared to identically sized cockles at the top (Sutherland, 1980). Using the investigations of Sutherland in his 1980 study, it is possible to adjust the average AFDM value for a size class of cockle given the mean shoreheight of a patch across the max and min shoreheights of the entire range of cockle beds. This then provides an appropriately adjusted value of AFDM for each size class per cockle bed location. During the course of wintering periods, the energy content of the shellfish is known to decline and no longer be in proportion to the size of shell (Zwarts, 1991; Zwarts and Wanink, 1993). This is replicated in the Burry Inlet models by decreasing cockles by 39% and mussels by 49% over the course of the whole model run which correspond to studies of shellfish in this area.

As the energy content of the model has been updated to kJ energy, as opposed to AFDM, conversion multiplier of 22.5kJ g-1 was applied per gram of AFDM (Zwarts and Wanink, 1993).

12.4 Foragers

Six types of foraging individual were included in the model, four types of oystercatcher and two fishermen. The inclusion of shellfishermen as individual foragers allows another point of validation against observational data from 2000-01 in regards to the tonnage of shellfish that they took that winter as well at the impact of disturbance on cockle beds.

12.4.1 Oystercatchers

The oystercatcher population (12,300 for 2000-01 winter on the Burry Inlet) contained 14% immature and 86% adult individuals with an overall split of 52% using hammering and 48% stabbing techniques. Within each age class 20% immatures stabbed whilst 80% hammered, and 43% adults stabbed with 57% adults hammering.

All oystercatchers arrived on day 1 and continue through the winter until the 24th February (day 177) when a random selection totalling 9,519 emigrated out of the model to match observations made at that time of the population left (2,781) going into March 2001 (Stewart, 2001). Only adult birds emigrated out as immatures are known to leave later in the season during their first winter and the remaining individuals stayed to the end of the model (March 31st 2001, day 212). Oystercatchers can access all shellfish beds and the upshore in relation to their exposure by the tides but fields could only be used when it was daylight.

Birds started off in the model with an arrival mass (grams, see Table 12.1) specific to their age class and aimed to increase this through to a mid-target mass on day 106 (15th December 2000) before continuing on towards a final target mass . These masses are converted into energy (kJ) at a rate of

34.3kJ g-1 of a bird’s fat reserves (Kersten and Piersma, 1987). A starvation mass is included for each age class (Table 12.1) based of field observations of starved birds and if birds do not meet their daily energy requirements (target mass less starvation mass) they will be removed from the model having ‘starved’. This is the only form of mortality for oystercatchers in this model.

Four types of diet are available to oystercatchers – field prey, upshore prey, cockles and mussels – and of these birds can only access cockles between 15-25mm and mussel 30-65mm. There is a prey assimilation efficiency for all diets of 85% as not all energy contained a prey item can be assimilated by a bird and additionally fat is only stored successfully at a rate of 88.4% . When consuming shellfish it is known that oystercatcher leave behind 10% of flesh in the shells thus reducing the total taken to 90% per item of resource.

Birds forage at rates governed by their own foraging efficiencies is then be impacted upon through the presence of competitors and disturbance from fishermen using the same patch. All oystercatchers are parameterised with a unique foraging efficiency based around off a normal distribution around 1 (0.125 SD) and experience no difference in night efficiency. Dominance constants are used to calculate the effect of interference and again were unique to each individual taken from a uniform distribution between 0 and 1.

Intake rates for Upshore and Field Prey were set at 0.67 and 0.53 mg AFDM sec -1 and Fields have an additional parameter to prevent foraging on field below 6°C . These are converted into kJ h-1 and divided by the available energy density for each diet on the patch. When foraging on shellfish the interference free intake rate (IFIR) is calculated in the same manner as (Stillman, Goss-Custard and Wood, 2014) and then affected by interference:

IFIR  f

IFIR max B B50  B

(1)

In this equation for IFIR (mg s-1), f stands for an individual’s foraging efficiency, B is the density of biomass of prey for size range consumed (mg m-2), IFIRmax represents the maximum intake rate and B50 is the density of prey biomass when at 50% of the maximum intake rate. The specific cockle and mussel values for this equation can be found in Table 12.1.

Disturbance from shellfishers is incorporated into the competitor density that each bird experiences. Each shellfisher creates a disturbance area with a 100m radius when present on a bed and this is then removed from the total available area on a patch per fisher given the area available at a specific tidal stage. The subsequent non-disturbed area is used to work out a density of birds given the count on a patch multiplied by an aggregation factor (cockles = 10, mussels = 6) and compared to the regulated density of 0.005384 cockles and 0.0045 mussels (Bowgen, 2016). If the density is greater than the predefined cockle bed threshold (100 birds ha-1, Stillman et al., 2002) or mussel bed thresholds (hammerers 51.2 birds ha-1 , stabbers 65.4 birds ha-1) then interference is applied per the

following equations (Equation 2 = cockles, Equation 3 = mussels hammerer, Equation 4 = mussels stabbers) :

 max( g , D)  STI     0.01 

(  ( 0.050.05*r )

 max( g , D)  STI     0.00512 

(  ( 0.1680.081*r 0.0014*Day)

 max( g , D)  STI     0.00654 

(  ( 0.1510.535*r 0.0022*Day)

(2)

(3)

(4)

Where to calculate susceptibility to interference (STI) g = regulated density, D = con-specific density (m-2), r = dominance rank and n = count of con-specifics. Rank is determined by comparing the dominance constant of an individuals against all other birds to work out it how many birds are more dominant over it.

The maximum intake rate limits the maximum food that a bird can take within a time step following previous work (Kirkwood, 1983) based of an equation as below:

0.72   550    MaxIR  1713 *     1000    

 Assimilati onEfficiency * DietEnergyDensity  (5)

Oystercatcher metabolism whilst feeding and resting is calculated from an equation stating that 648 kJ per day is used plus 30 kJ for 20 minutes of flying per day. When the temperature is lower than the 10°C lower critical temperature (LCT), 31.8kJ is added per degree below the LCT . There no movement time between patches in the Burry Inlet as all birds can fly between the most distant patches within 1 hour and so is incorporated in the main 20 mins of flying per day.

Using the parameters detailed above, oystercatchers make a decision of whether to forage upon a certain patch to maintain their energy reserves (maintain their fitness) or move to the Roosts patch to rest. Birds that do not reach a body mass greater than their starvation mass will be removed from the model having “starved”.

The decision rule to derive the fitness component “Starved” is based on a “satisficing” method that allows birds to choose adequate patches to forage upon rather than purely “rate-maximise” and

always go to the best possible patch (Stillman et al., 2005). Used previously in other MORPH IBMs (Stillman et al., 2005; Bowgen, 2016), this allows a realistic distribution of birds throughout the available patches. Birds with an energy store of less than 95% of their target energy store or with a potential assimilation rate greater than the average of the past 24hours rates need to forage but are then asked if there are actually “starving” or not. If this is true, then they will rate-maximise to the best possible patch otherwise they will satisfice to an adequate patch location. Birds that do not fit any of these criteria will roost on the land.

12.4.2 Shellfishers

Using the reports from 2001 (Stewart, 2001; West et al., 2001) and West et al., 2003 we were able to correctly parameterise 116 cockle fishermen taking 4,535 tonnes of cockles. No mussel fishermen were included in these observations so this forager type was left unpopulated but ready for inclusion in future studies. The 116 cockle fishers arrived on day 1 in the model and stayed until the end foraging during daylight hours everyday bar Sundays on cockle beds alone.

Unlike oystercatchers, shellfishers do not have a strict arrival mass or targets to reach and thus were parameterised with a high arbitrary value mass of 1,000,000g that was to be maintained throughout the model run. The majority of the oystercatcher parameters are set as 0 for fishermen as they do not require constants such as foraging efficiencies and dominance nor competitor densities and interference (Table 12.1). Metabolic rates are set as 1 to allow processing of cockles harvested from the beds and intake rates and maximum intake rates are set per the total tonnage that was recorded as being taken over the 2000-01 winter. No mussels are taken but cockles between 20-45mm were harvested to a total of 4,535 tonnes (West et al., 2001). Taking into account the 116 cockle fishers and 1,716 fishable tides and a fresh flesh to AFDM conversion of 0.0372 an intake rate equation of (22.5*848)/CockleDietEnergyDensity was calculated with the same maximum intake rate and 0 assimilation efficiency.

To mimic the knowledge of fishermen on the Burry Inlet, the decision rule for Shellfishers is set to be rate-maximising. If their energy consumption rate is greater than 0 then they will forage at the best possible location available.

12.6 Validation of models

During the development of the 2000-01 Burry Inlet model, validation was carried out against known observations of oystercatcher behaviour during the winter of 2000-01. A previous report on the oystercatcher populations and shellfisheries of the Burry Inlet provides observed values of time spent feeding, habitat use and winter population totals to aid in this process (Stewart, 2001). The predicted model outputs were compared with the observed values to ensure the model correctly replicates the Burry Inlet during the 2000-01 winter periods.

12.6.1 Time spent feeding

Observations of time spent feeding were made between January and March on cockle and mussel beds in the Burry Inlet (Stewart, 2001). Taken over an average of 10 hours of daylight leading up to high tide, neap tide observations were selected for validation purposes due lower bird numbers on spring tides when birds were out of sight in gullies and dips across the patches. Percentage of birds feeding and not feeding were calculated for each half hourly observation and averaged for each 10 hour day.

The proportion of time spent feeding on the four neap tide days (2 cockles beds, 2 mussels beds) were compared to the same days in the Burry Inlet 2000-01 model and averaged over 10 hours. The predictions closely match the observed values with model birds spending slightly more time foraging on both cockles and mussels in the models (Table 12.9).

Table 12.9 Comparison of time spent feeding of oystercatchers between a MORPH model of the Burry Inlet and observations in 2000-01.

Observed Predicted Difference (minutes) Percentage difference

Cockles Mussels Average Time Spent Feeding over 10 hours 5.48 4.08 5.75 4.60 16 31 4.9% 12.6%

12.6.2 Habitat use

Low tide counts of absolute oystercatcher numbers were carried out on seven occasions between the 4th January 2001 and the 9th February 2001 covering four neap and three spring tides. For the purpose of validation the counts on each section were summarised into total numbers on mussel beds, cockle beds and mussel crumble before being averages across spring and neap cycles. It should be noted that cockle beds are represented by mudflat and sand sections in the report and numbers roosting on the saltmarsh were not included.

Predictions of habitat use were requested and averaged from the models for nine spring and nine neap daylight tides throughout January and February. The modelled outputs closely matched the foraging habitat the birds used within 3.1% giving confidence in the ability of the model to predict bird’s behaviours (Table 12.10)

Table 12.10 Comparison of percentage of oystercatcher habitat use between a MORPH model of the Burry Inlet and observations in 2000-01.

Spring Tides

Observed Predicted Difference

91.67 89.07 2.60%

7.98 7.49 0.49%

Mussel Crumble 0.35 3.44 3.09%

Neap Tides

Observed Predicted Difference

87.07 84.36 2.71%

11.59 12.01 0.42%

1.34 3.63 2.29%

Cockles

Mussels

12.7 Parameterisation for 2004/05 Burry Inlet

Following parameterisation for 2000-01 on the Burry Inlet, the model was then re-parametrised for a similar winter period 1st September 2004 to 31st March 2005. To allow comparison with 2000-1, the majority of parameters were kept the same whilst changes in resources and oystercatcher number replicated the new period. A smaller number of oystercatchers were observed that winter and so the model contained only 5,749 oystercatchers split in the same proportions as before between immatures and adults (Table 12.5). No mussel beds were included in this model and during this winter only five cockle beds are present (Table 12.6) with considerably fewer larger invertebrates (Table 12.7). Tables 12.5 to 12.8 detail these changes in full.

12.8 Overall changes from previous models

In direct comparison with the most recent model (Stillman, Goss-Custard and Wood, 2014), the main updates have been to the forager decision rule and the method for including fishermen. Oystercatchers now follow a “Satisficing” rule which allows rate maximising when close to starvation but otherwise includes a small margin of error to distribute birds across any patch that is adequate (Stillman et al., 2005). This more closely mimics the distribution of wading birds on an estuary rather than assume an absolute “perfect knowledge”.

The inclusion of fishermen in the model parameterised them as individual foragers rather than proportional chances of disturbance or loss of resources on a patch. The fishermen are now quicker to manipulate and adjust based on total number of individuals per winter, days they can forage upon and tonnage of shellfish taken each month. In future, the use of these foraging shellfishers will allow greater flexibility in answering questions relating to the shellfishing industry and waders birds.

12.9 Parameter values used in shellfishMORPH The values of the parameters that are not specific to the Burry Inlet, such as the daily energy requirements of an oystercatcher, are derived from a review of the literature carried out by Professor Goss-Custard over the winter 2016-17. In due course, this review will be put on-line as an Appendix to this report.

Table 12.1 Parameters for 2000/01 Burry Inlet Model. Time and environmental conditions Parameter Duration of model Daylight Tide Heights (m Chart Datum) Temperature (°C)

Prey Patches Parameter Number of patches

Patch areas (m2) (see Table 12.2)

Shoreheights (m CD) Available

Energy density of prey flesh Number of size classes

Width of size classes (mm)

Fields/Upshore Cockle beds Mussel beds Mussel crumble beds Fields/Upshore Cockle beds

Mussel beds Mussel crumble beds Min 1.1m; Max 4.35m Oystercatchers Fields Beds Fishermen Beds Field Prey Upshore Prey Cockles Mussels Field/Upshore Prey Cockles Mussels

Density of prey at start of

Field Prey

Value 1st September 2000 – 31st March 2001 (212 days), 5,088 hours (Timesteps) Hourly, based on US Naval Observatory website (1/9/2000-31/3/2001) Hourly, based on TideWizard values for Burry Port (1/9/2000-31/3/2001) Hourly, based off 50 year average for the Exe estuary.

1 each 9 5 4 50,000 each (arbitrary) 859000; 2892000; 1286000 ;630000; 954000; 1081000; 1469000; 2318000; 854000 509700; 28100; 39100; 14500; 47600 61300; 361600; 40400; 53600 LiDAR survey (See Table 12.2) During daylight Tide permitting Daylight, tide permitting, not a Sunday 22.5 kJ g-1 1 1 8 12 Arbitrary/Non applicable 5-10; 10-15; 15-20; 20-25; 25-30; 30-35; 3540; 40-45 5-10; 10-15; 15-20; 20-25; 25-30; 30-35; 3540; 40-45; 45-50; 50-55; 55-60; 60-65 100

winter (m-2)

Expression to update resource density (over-winter non-bird mortality of prey) Ash-Free dry mass (AFDM) at start of winter (g)

Express to update resource energy (over-winter decline AFDM) Foragers Parameters Number of Forager Types

Arrival Day Departure Day

Upshore Prey Cockles Mussels Field Prey Upshore Prey Cockles Mussels Field Prey Upshore Prey Cockles Mussels Field /Upshore Prey Cockles Mussels

100 See Table 12.3 See Table 12.3 100 100 0.30 – 30% decline over winter 0.05 – 5% decline over winter 0.1 0.1 See Table 12.4 See Table 12.4 none 0.39 – 39% decline over winter 0.45 – 45% decline over winter

Oystercatcher Hammerer Stabber Cockle Fishermen Mussel Fishermen

Immature and Adult birds (14:86 ratio) Imm 339; Adult 6044 Imm 1358; Adult 4559 116 0 1 10000 10000 for 2,781, 177 for 9,519 (24/02/01) 10000 34.3 kJ g-1 483 503 1,000,000 550 550 510 598 340 350 Normal distribution around 1 (0.125 SD) 0 1 0 Uniform distribution between 0 and 1 10 6 53.84 45 100 -0.5; 0.5; 0.01 (100/ha)

Oystercatchers Imm Oystercatchers Adult Fishermen

Energy density of fat reserves Arrival mass (g) Oystercatchers Imm Oystercatchers Adult Fishermen Mid Target mass (g) Oystercatchers Imm Day 106 for Oystercatchers Oystercatchers Adult Final Target mass (g) Oystercatchers Imm Oystercatchers Adult Starvation mass (g) Oystercatchers Imm Oystercatchers Adult Foraging Efficiency Oystercatchers Fishermen Night Efficiency Oystercatchers Fishermen Dominance Oystercatchers Aggregation Factor Cockles Mussels Regulated Density (/ha) Cockles Mussels Disturbance radius (m) Oystercatchers Interference Coefficients Oystercatchers Cockle a; b; c; d Oystercatchers Mussel a, b (Rank); c (Day); Hammerer d (Threshold) Stabber Diet types Oystercatchers only

-0.168; 0.081; -0.0014; 0.00512 (51.2/ha) -0.151; 0.535; -0.0022; 0.00654 (65.4/ha) Fields Diet

Fishermen Number of resources in each Oystercatchers diet and size classes covered

Fishermen Rate of consumption (mg AFDM/second)

Oystercatchers Fields Upshore Cockles

(kJ/hour)

Oystercatchers

0.53 (for >6°C) 0.67 ((237.7687*DietEnergyDensity)/ (1.45813+DietEnergyDensity)) ((407.214*DietEnergyDensity)/ (11.939+DietEnergyDensity)) (22.5*848)/DietEnergyDensity (1713*(550/1000)^0.72)/(Assimilation Efficiency*DietEnerfyDensity) 678 (inc. 30 kJ for 20mins flight per day)

Oystercatchers Oystercatchers

10°C 31.8

Oystercatchers Oystercatchers Oystercatchers Oystercatchers

0.85 10% (0.9) 0.884 ((648+30)+ max(31.8*(10-Temperature, 0))/24 1 Satisficing Rate maximising

Mussels CockleFishers Maximum intake rate (kJ per hour) Energy expenditure – nonthermoregulatory (kJ d-1) Lower Critical Temperature Energy expenditure – thermoregulatory (kJ °C d-1) Prey assimilation efficiency Left over prey in shells Fat storage efficiency Feeding, resting metabolic rate (kJ/hr)

Fishermen Oystercatchers Fishermen

Fitness rule

Upshore Diet Cockle Diet Mussel Diet Cockle Fisher Diet Mussel Fisher Diet 1 1 6; Cockles 15-45mm 7; Mussels 30-65 mm 5; Cockles 20-45 mm 3; Mussels 40-65mm

Table 12.2 Characteristics of Burry Inlet model patches in 2000/01. (C= cockle bed, M = mussel bed, MC = mussel crumble bed). Patch Name

Water Land Roosts Home Fields Upshore Pwll NorthSide1 NorthSide2

C M MC C C C

Maximum Exposed Area (m2) 1 1 10000 10000 50000 50000 859000 2892000 1286000

Minimum Shoreheight (m CD) 0 0 0 0 0 1.1 1.4 3.54 1.4

Maximum Shoreheight (m CD) 0 0 0 0 0 8.14 6.51 7.27 7.52

Oystercatcher Cockle Mussel patch Fisher Fisher patch patch 0 0 0 0 0 0 1 0 0 0 1 1 1 0 0 1 0 0 1 1 0 1 1 0 1 1 0

MiddleBank Cheriton SouthSide1 SouthSide2 SouthSide3 OnchorDraw WhitefordSands WhitefordPoint LPGCarregddu LPGCarregfach Pwll BurryPill LlanrhidianSands LlanelliPenrhyn EastofLlanelli

C C C C C C M M M M M MC MC MC MC

630000 954000 1081000 1469000 2318000 854000 509700 28100 39100 14500 47600 61300 361600 40400 53600

1.46 3 2.31 1.4 1.4 2.54 1.1 3.44 1.4 1.4 1.4 1.2 4.35 4.01 1.4

5.86 7.9 7.26 7.22 6.87 7.15 8.14 4.73 7.04 6.89 6.05 4.12 7.75 7.19 7.14

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 1 1 1 1 1 1 1 1 1

Table 12.3a Start of winter numerical density of prey size classes in the Burry Inlet model 2000/01. Patch Name

Fields Prey Fields 100 Upshore 0 Pwll 0 North Side1 0 North Side2 0 Middle Bank 0 Cheriton 0 South Side1 0 South Side2 0 South Side3 0 Onchor Draw 0 Whiteford Sands 0 Whiteford Point 0 LPG Carregddu 0 LPG Carregfach 0 Pwll 0 Burry Pill 0 Llanrhidian Sands 0 Llanelli Penrhyn 0 East of Llanelli 0

Upshore Prey 0 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

5-10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cockles in mm size classes (per m2) 10-15 15-20 20-25 25-30 30-35 35-40 0 0 0 0 0 0 0 0 0 0 0 0 0 344.5 469.5 92.2 1.3 1.3 0 349.7 243.4 72.9 6.4 0.5 0 77.8 105.4 61.3 5.4 0.4 0 0.1 139.7 237.2 18.6 0.5 0 59.7 355.5 193.7 33 0.7 0 138.2 218.2 89.1 10.9 0.4 0 93.1 191.4 98.3 13.2 0.4 0 268.4 349.8 93.7 8.8 0.3 0 160.3 493.9 186.4 22.2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

40-45 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Table 12.3b Start of winter numerical density of prey size classes in the Burry Inlet model 2000/01. Patch Name Fields Upshore

Mussels in mm size classes (per m2) 5-10 10-15 15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Pwll North Side1 North Side2 Middle Bank Cheriton South Side1 South Side2 South Side3 Onchor Draw Whiteford Sands Whiteford Point LPG Carregddu LPG Carregfach Pwll Burry Pill Llanrhidian Sands Llanelli Penrhyn East of Llanelli

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 376.7 231.7 163.8 73.3 213.2 231.7 448.8 120 746.7

0 0 0 0 0 0 0 0 0 268.3 180 136.8 104.3 111.3 180 401.5 222.5 20

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 195.8 136.3 114.5 148.3 154.5 187.5 180 112.5 27.5 2.5 145 83.3 58.3 40 23.3 82.5 22.5 8.3 2.5 0 88.8 73.8 102.5 88.8 85 187.5 180 112.5 27.5 2.5 491.3 279.3 108 45 20.5 115 20 2.5 0 0 71.3 462.5 988.8 620 76.3

0 0 0 0 0 0 0 0 0 75.8 5 1.8 0 53.8 5 0.5 0 1.3

0 0 0 0 0 0 0 0 0 26.3 0 3.3 0 28.8 0 0.5 0 0

0 0 0 0 0 0 0 0 0 10.5 0 0 0 7 0 0 0 0

Table 12.4a Start of winter mass (g AFDM) of prey size classes in the Burry Inlet model 2000/01. Patch Name Fields Upshore Pwll North Side1 North Side2 Middle Bank Cheriton South Side1 South Side2 South Side3 Onchor Draw Whiteford Sands Whiteford Point LPG Carregddu LPG Carregfach Pwll Burry Pill Llanrhidian Sands Llanelli Penrhyn East of Llanelli

Fields Upshore Prey Prey 5-10 0.1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

10-15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cockles in mm size classes (g AFDM) 15-20 20-25 25-30 30-35 35-40 40-45 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0482 0.1084 0.2105 0.3702 0.6373 0 0.0558 0.1256 0.2438 0.4287 0.7380 0 0.0510 0.1147 0.2226 0.3915 0.6739 0 0.0465 0.1045 0.2029 0.3569 0.6144 0 0.0560 0.1260 0.2445 0.4300 0.7403 0 0.0527 0.1186 0.2302 0.4048 0.6968 0 0.0501 0.1127 0.2188 0.3848 0.6624 0 0.0492 0.1108 0.2150 0.3782 0.6510 0 0.0529 0.1190 0.2309 0.4061 0.6991 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Table 12.4b Start of winter mass (g AFDM) of prey size classes in the Burry Inlet model 2000/01.

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Patch Name

Mussels in mm size classes (g AFDM) 10-15 15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65

510 Fields Upshore Pwll North Side1 North Side2 Middle Bank Cheriton South Side1 South Side2 South Side3 Onchor Draw Whiteford Sands Whiteford Point LPG Carregddu LPG Carregfach Pwll Burry Pill Llanrhidian Sands Llanelli Penrhyn East of Llanelli

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0.023 0.033 0.037 0.014 0.017 0.033 0.033 0.035 0.016

0 0 0 0 0 0 0 0 0 0 0 0.058 0.072 0.087 0.066 0.047 0.072 0.072 0.075 0.043

0 0 0 0 0 0 0 0 0 0 0 0.121 0.133 0.173 0.160 0.105 0.133 0.133 0.138 0.093

0 0 0 0 0 0 0 0 0 0 0 0.222 0.223 0.307 0.267 0.205 0.223 0.223 0.228 0.177

0 0 0 0 0 0 0 0 0 0 0 0.373 0.347 0.501 0.352 0.364 0.347 0.347 0.351 0.308

0 0 0 0 0 0 0 0 0 0 0 0.589 0.511 0.771 0.397 0.602 0.511 0.511 0.513 0.500

0 0 0 0 0 0 0 0 0 0 0 0.882 0.719 1.129 0.402 0.941 0.719 0.719 0.717 0.769

0 0 0 0 0 0 0 0 0 0 0 1.269 0.979 1.593 0.376 1.406 0.979 0.979 0.971 1.133

0 0 0 0 0 0 0 0 0 0 0 1.767 1.296 2.178 0.332 2.026 1.296 1.296 1.277 1.610

Table 12.5 Changes to parameters for 2004/05 Burry Inlet Model Time and environmental conditions Parameter Duration of model (dates/timesteps) Daylight Tide Heights (m CD) Temperature (°C)

Prey Patches Parameter Number of patches

Patch areas (m2)

Shoreheights (m CD) Number of size classes

Fields/Upshore Cockle beds Mussel beds Mussel crumble beds Fields/Upshore Cockle beds Min 1.4m; Max 7.72m Field Prey

Value 1st September 2004 – 31st March 2005. 5,088 hours (Timesteps) Hourly, based on US Naval Observatory website (1/9/2004-31/3/2005) Hourly, based on TideWizard values for Burry Port (1/9/2004-31/3/2005) Hourly, based off 50 year average for the Exe estuary

1 each 5 0 0 50,000 each (arbitrary) 253000; 5057000; 7333000; 5807000; 7889000 LiDAR survey. See Table 13.2 1

0 0 0 0 0 0 0 0 0 0 0 2.393 1.676 2.901 0.281 2.831 1.676 1.676 1.643 2.222

Foragers Parameters Number of Forager Types

Upshore Prey Cockles Mussels

1 8 0

Oystercatcher Hammerer Stabber Cockle Fishermen Mussel Fishermen

Immature and Adult birds (14:86 ratio) Imm 0; Adult 0 Imm 793; Adult 4956 0 0

Table 12.6 Characteristics of Burry Inlet model patches in 2004/05. (C= cockle bed, M = Mussel bed, MC = mussel crumble) Patch Name

Water Land Roosts Home Fields Upshore Burry Port Penrhyn North R Loughour Penclawdd Llanrhidian

C M MC C C C C C

Maximum Exposed Area (m2) 1 1 10000 10000 50000 50000 253000 5057000 7333000 5807000 7889000

Minimum Shoreheight (m CD) 0 0 0 0 0 1.4 1.4 1.4 1.4 1.4 1.4

Maximum Shoreheight (m CD) 0 0 0 0 0 7.72 4.26 7.72 7.71 7.15 7.21

Oysterc -atcher patch 0 0 1 0 1 1 1 1 1 1 1

Cockle Fisher patch 0 0 0 1 0 0 1 1 1 1 1

Mussel Fisher patch 0 0 0 1 0 0 0 0 0 0 0

Table 12.7 Start of winter numerical density of each prey size class in the Burry Inlet model 2004/05. Patch Name

Fields Prey Fields 100 Upshore 0 0 Burry Port 0 Penrhyn North R Loughour 0 0 Penclawdd 0 Llanrhidian

Upshore Prey 0 100 0 0 0 0 0

5-10 0 0 0 0 0 0 0

Cockles in mm size classes (per m2) 10-15 15-20 20-25 25-30 30-35 35-40 0 0 0 0 0 0 0 0 0 0 0 0 0 0 480 0 0 0 0 0 588 65 4.5 0.5 0 0 772.4 100 6.9 0.3 0 0 759.3 83.6 7.1 0 0 0 602.6 155.8 16.3 2.6

40-45 0 0 0 0 0 0 0

Table 12.8 Start of winter mass (g AFDM) of each prey size class in the Burry Inlet model 2004/05. Patch Name Fields Upshore

Fields Prey 0.1 0

Upshore Prey 5-10 0 0 0.1 0

Cockles in mm size classes (g AFDM) 10-15 15-20 20-25 25-30 30-35 35-40 0 0 0 0 0 0 0 0 0 0 0 0

40-45 0 0

Burry Port Penrhyn North R Loughour Penclawdd Llanrhidian

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0.0289 0.041 0.0404 0.0877 0.0488

0 0.1027 0.0989 0.1977 0.097

0 0.2115 0.226 0.3797 0.2188

0 0.4485 0.355 0 0.4022

0 0 0 0 0

0 0 0 0 0