/// <summary>
/// Maintenance energy requirement.
/// Energy required to maintain this prawns weight
/// </summary>
/// <param name="Prawns"></param>
/// <param name="StressTemp"></param>
/// <param name="StressSalinity"></param>
/// <returns>(kJ/prawn/d)</returns>
private double EnergyMaintenance(PrawnCohort Prawns, double StressTemp, double StressSalinity)
{
double energy;
energy = Km1 * Math.Pow(Prawns.LiveWeight, Km2);
energy = energy * StressTemp * StressSalinity;
return(energy);
}
/// <summary>
/// Calculate todays potential total consumption of Dry Matter (per prawn).
/// Function was derived by reverse-engineering the prawn growth rate equation of Jackson and Yang (1998).
/// Which is why we first calculate intake, then work out what the consumption must have been.
/// </summary>
/// <param name="Prawns"></param>
/// <param name="StressStock"></param>
/// <param name="StressTemp"></param>
/// <returns>(g DM/prawn/d</returns>
private double PotentialDMConsumedPerPrawn(PrawnCohort Prawns, double StressStock, double StressTemp)
{
double intake, consumed;
intake = Ki1 * Math.Pow(Prawns.LiveWeight, Ki2);
intake = intake * StressStock * stressTemp;
consumed = (1 / Ki4) * intake; //invert consumption efficiency to go back the other way.
return(consumed);
}
private Feed FeedIntake(PrawnCohort Prawns, Feed IntakeFeedPP)
{
double dm, n, de;
dm = IntakeFeedPP.DryMatter * Prawns.NumberOfPrawns * g2kg;
n = IntakeFeedPP.Nitrogen * Prawns.NumberOfPrawns * g2kg;
de = IntakeFeedPP.DigestibleEnergy * Prawns.NumberOfPrawns;
Feed intake = new Feed(IntakeFeedPP.FeedName, dm, n, de);
return(intake);
}
private Feed FeedDigested(PrawnCohort Prawns, Feed DigestedFeedPP)
{
double dm, n, de;
dm = DigestedFeedPP.DryMatter * Prawns.NumberOfPrawns * g2kg;
n = DigestedFeedPP.Nitrogen * Prawns.NumberOfPrawns * g2kg;
de = DigestedFeedPP.DigestibleEnergy * Prawns.NumberOfPrawns;
Feed digested = new Feed(DigestedFeedPP.FeedName, dm, n, de);
return(digested);
}
/// <summary>
/// Return the prawns that died today as a feed type to add back into the pond.
/// </summary>
/// <param name="Deaths">Number of prawns that died today</param>
/// <param name="Prawns">Current Prawns that are in the pond</param>
/// <returns>Feed to be added to the pond</returns>
private Feed DeadPrawnsAsFeed(int Deaths, PrawnCohort Prawns)
{
double Kdm = 0.26; //dry matter content of prawns
double de2dm = 16; //a reasonable guess.
double dm, n, de;
dm = Kdm * Deaths * (Prawns.LiveWeight * g2kg);
n = Deaths * (Prawns.NitrogenMass * g2kg);
de = de2dm * dm;
Feed deadPrawnsAsFeed = new Feed("DeadPrawns", dm, n, de);
return(deadPrawnsAsFeed);
}
/// <summary>
/// Number of prawns that died today.
/// Background deaths (approximately equivalent to 20% per year)
/// plus additional deaths due low salinity and high ammonium.
/// (using an equation fitted to the data of Li et al 2007)
/// </summary>
/// <param name="Prawns">Current Prawns</param>
/// <param name="Salinity">Salinity (ppt)</param>
/// <param name="Ammonium">Ammonium (mg/litre)</param>
/// <returns>(prawns/d)</returns>
private int Mortality(PrawnCohort Prawns, double Salinity, double Ammonium)
{
double background = Kd1;
double lowSalinity = MathUtilities.Divide(Salinity, Kd3, 0.0);
lowSalinity = 1.0 - lowSalinity;
lowSalinity = Math.Max(0, lowSalinity);
double highAmmonium = MathUtilities.Divide(Ammonium, Kd4, 0.0);
highAmmonium = highAmmonium - 1.0;
highAmmonium = Math.Max(0, highAmmonium);
highAmmonium = Math.Pow(highAmmonium, Kd5);
double additional = Kd2 * lowSalinity * highAmmonium;
double deathRate = background + additional;
double deadPrawnNumber = Prawns.NumberOfPrawns * (1.0 - Math.Exp(-deathRate));
return((int)deadPrawnNumber);
}
/// <summary>
/// Restricts the Potential total amount of DM Consumed (per prawn) by what is actually available in the pond to be consumed.
/// </summary>
/// <param name="FoodAvailable">Food that is currently in the pond</param>
/// <param name="Prawns">Prawns that are currently in the pond</param>
/// <param name="PotentialDMConsumedPP">Amount of DM each prawn would like to eat</param>
/// <returns>Amount of DM each prawn will actually get to eat. (g DM/prawn)</returns>
private double CheckEnoughFoodToConsumeToday(Food FoodAvailable, PrawnCohort Prawns, double PotentialDMConsumedPP)
{
double potDMConsumed_kg = PotentialDMConsumedPP * Prawns.NumberOfPrawns * g2kg; //convert from grams to kg.
//Check there is any food in the pond.
if ((FoodAvailable.TotalDM <= 0.0) && (Prawns.NumberOfPrawns > 0))
{
Summary.WriteWarning(this, "There is no food in the pond. The prawns are starving");
return(0.0);
}
//Check there is enough food in the pond
if (potDMConsumed_kg > FoodAvailable.TotalDM)
{
Summary.WriteWarning(this, "Not enough food in pond for prawns to eat today." +
Environment.NewLine + "Reducing dry matter consumed from " + Math.Round(potDMConsumed_kg, 3) + " (kg) to " + Math.Round(FoodAvailable.TotalDM, 3) + " (kg)");
//just give them what is there
return(MathUtilities.Divide(FoodAvailable.TotalDM, Prawns.NumberOfPrawns, 0.0) * kg2g); //convert kg to grams
}
return(PotentialDMConsumedPP);
}
/// <summary>
/// Calculate todays potential total consumption of Dry Matter (per prawn).
/// Function was derived by reverse-engineering the prawn growth rate equation of Jackson and Yang (1998).
/// Which is why we first calculate intake, then work out what the consumption must have been.
/// </summary>
/// <param name="Prawns"></param>
/// <param name="StressStock"></param>
/// <param name="StressTemp"></param>
/// <returns>(g DM/prawn/d</returns>
private double PotentialDMConsumedPerPrawn(PrawnCohort Prawns, double StressStock, double StressTemp)
{
double intake, consumed;
intake = Ki1 * Math.Pow(Prawns.LiveWeight, Ki2);
intake = intake * StressStock * stressTemp;
consumed = (1 / Ki4) * intake; //invert consumption efficiency to go back the other way.
return consumed;
}
/// <summary>
/// Restricts the Potential total amount of DM Consumed (per prawn) by what is actually available in the pond to be consumed.
/// </summary>
/// <param name="FoodAvailable">Food that is currently in the pond</param>
/// <param name="Prawns">Prawns that are currently in the pond</param>
/// <param name="PotentialDMConsumedPP">Amount of DM each prawn would like to eat</param>
/// <returns>Amount of DM each prawn will actually get to eat. (g DM/prawn)</returns>
private double CheckEnoughFoodToConsumeToday(Food FoodAvailable, PrawnCohort Prawns, double PotentialDMConsumedPP)
{
double potDMConsumed_kg = PotentialDMConsumedPP * Prawns.NumberOfPrawns * g2kg; //convert from grams to kg.
//Check there is any food in the pond.
if ((FoodAvailable.TotalDM <= 0.0) && (Prawns.NumberOfPrawns > 0))
{
Summary.WriteWarning(this, "There is no food in the pond. The prawns are starving");
return 0.0;
}
//Check there is enough food in the pond
if (potDMConsumed_kg > FoodAvailable.TotalDM)
{
Summary.WriteWarning(this, "Not enough food in pond for prawns to eat today." +
Environment.NewLine + "Reducing dry matter consumed from " + Math.Round(potDMConsumed_kg,3) + " (kg) to " + Math.Round(FoodAvailable.TotalDM, 3) + " (kg)");
//just give them what is there
return MathUtilities.Divide(FoodAvailable.TotalDM, Prawns.NumberOfPrawns, 0.0) * kg2g; //convert kg to grams
}
return PotentialDMConsumedPP;
}
/// <summary>
/// Harvest the Pond of Prawns.
/// All prawns are removed from the pond.
/// </summary>
public void HarvestPond()
{
prawns = new PrawnCohort(0, 0.0, 0.0);
}
/// <summary>
/// Return the prawns that died today as a feed type to add back into the pond.
/// </summary>
/// <param name="Deaths">Number of prawns that died today</param>
/// <param name="Prawns">Current Prawns that are in the pond</param>
/// <returns>Feed to be added to the pond</returns>
private Feed DeadPrawnsAsFeed(int Deaths, PrawnCohort Prawns)
{
double Kdm = 0.26; //dry matter content of prawns
double de2dm = 16; //a reasonable guess.
double dm, n, de;
dm = Kdm * Deaths * (Prawns.LiveWeight * g2kg);
n = Deaths * (Prawns.NitrogenMass * g2kg);
de = de2dm * dm;
Feed deadPrawnsAsFeed = new Feed("DeadPrawns", dm, n, de);
return deadPrawnsAsFeed;
}
/// <summary>
/// Harvest the Pond of Prawns.
/// All prawns are removed from the pond.
/// </summary>
public void HarvestPond()
{
prawns = new PrawnCohort(0, 0.0, 0.0);
}
/// <summary>
/// Add Prawns to the Pond.
/// Any existing prawns in the pond are removed first.
/// </summary>
/// <param name="NumberOfPrawns"></param>
/// <param name="LiveWeight">(g/prawn)</param>
/// <param name="NitrogenMass">(g N/prawn)</param>
public void AddPrawnsToPond(int NumberOfPrawns, double LiveWeight, double NitrogenMass)
{
prawns = new PrawnCohort(NumberOfPrawns, LiveWeight, NitrogenMass);
}
/// <summary>
/// Maintenance energy requirement.
/// Energy required to maintain this prawns weight
/// </summary>
/// <param name="Prawns"></param>
/// <param name="StressTemp"></param>
/// <param name="StressSalinity"></param>
/// <returns>(kJ/prawn/d)</returns>
private double EnergyMaintenance(PrawnCohort Prawns, double StressTemp, double StressSalinity)
{
double energy;
energy = Km1 * Math.Pow(Prawns.LiveWeight, Km2);
energy = energy * StressTemp * StressSalinity;
return energy;
}
private void OnStartOfSimulation(object sender, EventArgs e)
{
prawns = new PrawnCohort(0, 0.0, 0.0);
}
/// <summary>
/// Number of prawns that died today.
/// Background deaths (approximately equivalent to 20% per year)
/// plus additional deaths due low salinity and high ammonium.
/// (using an equation fitted to the data of Li et al 2007)
/// </summary>
/// <param name="Prawns">Current Prawns</param>
/// <param name="Salinity">Salinity (ppt)</param>
/// <param name="Ammonium">Ammonium (mg/litre)</param>
/// <returns>(prawns/d)</returns>
private int Mortality(PrawnCohort Prawns, double Salinity, double Ammonium)
{
double background = Kd1;
double lowSalinity = MathUtilities.Divide(Salinity, Kd3, 0.0);
lowSalinity = 1.0 - lowSalinity;
lowSalinity = Math.Max(0, lowSalinity);
double highAmmonium = MathUtilities.Divide(Ammonium, Kd4, 0.0);
highAmmonium = highAmmonium - 1.0;
highAmmonium = Math.Max(0, highAmmonium);
highAmmonium = Math.Pow(highAmmonium, Kd5);
double additional = Kd2 * lowSalinity * highAmmonium;
double deathRate = background + additional;
double deadPrawnNumber = Prawns.NumberOfPrawns * (1.0 - Math.Exp(-deathRate));
return (int)deadPrawnNumber;
}
private Feed FeedIntake(PrawnCohort Prawns, Feed IntakeFeedPP)
{
double dm, n, de;
dm = IntakeFeedPP.DryMatter * Prawns.NumberOfPrawns * g2kg;
n = IntakeFeedPP.Nitrogen * Prawns.NumberOfPrawns * g2kg;
de = IntakeFeedPP.DigestibleEnergy * Prawns.NumberOfPrawns;
Feed intake = new Feed(IntakeFeedPP.FeedName, dm, n, de);
return intake;
}
private Feed FeedDigested(PrawnCohort Prawns, Feed DigestedFeedPP)
{
double dm, n, de;
dm = DigestedFeedPP.DryMatter * Prawns.NumberOfPrawns * g2kg;
n = DigestedFeedPP.Nitrogen * Prawns.NumberOfPrawns * g2kg;
de = DigestedFeedPP.DigestibleEnergy * Prawns.NumberOfPrawns;
Feed digested = new Feed(DigestedFeedPP.FeedName, dm, n, de);
return digested;
}
private void OnStartOfSimulation(object sender, EventArgs e)
{
prawns = new PrawnCohort(0, 0.0, 0.0);
}
/// <summary>
/// Add Prawns to the Pond.
/// Any existing prawns in the pond are removed first.
/// </summary>
/// <param name="NumberOfPrawns"></param>
/// <param name="LiveWeight">(g/prawn)</param>
/// <param name="NitrogenMass">(g N/prawn)</param>
public void AddPrawnsToPond(int NumberOfPrawns, double LiveWeight, double NitrogenMass)
{
prawns = new PrawnCohort(NumberOfPrawns, LiveWeight, NitrogenMass);
}
