144 The UMAP Journal 30.2 (2009) Task 5 Based on the values from Task 4, we assess which combinations from Task 3 are likely to create the most economic value for owners. Task 6 o We address policy changes that the Pacific Marine Fisheries Council can lopt to assist the Philippines in implementing long-term viability of a self-sustaining ecosystem. These policies center on harvesting all species at rates that keep the milkfish population under control and thus m polycultu Assumptions The growth rates of species are constant. Variability of amount of eggs laid by species is normally distributed. Humans are the only predator of milkfish The channel is not a closed system; excess population can emigrate to other reef locations The algae are a mix of cyan bacteria and red varieties(this assumption provides more-realistic results) Milkfish stop being omnivores when they mature, after which they eat only other animals It takes five years for milkfish to become sexually mature [Luna 2009] An adult milkfish is capable of eating an adult rabbitfish The fish pens currently hold approximately 58. 5 million fish. Milkfish weigh 500-600 g [Hambrey 19991 None of the other five species in the ecosystem model eats starfish Rabbitfish waste has the same composition as milkfish waste The prices found in Task 4 are estimates assumed from solitary sources Giant tiger prawns spawnnightly at a rate of 7.6% to 9% but only half of spawn hatch [Bray and Lawrence 1998 Giant tiger prawns have a mortality rate of 10% to 40% and an average weight of 106 g [Bray and Lawrence 1998]. Rabbitfish double in population every 1.4 to 4.4 years.144 The UMAP Journal 30.2 (2009) Task 5 Based on the values from Task 4, we assess which combinations from Task 3 are likely to create the most economic value for owners. Task 6 We address policy changes that the Pacific Marine Fisheries Council can adopt to assist the Philippines in implementing long-term viability of a self-sustaining ecosystem. These policies center on harvesting all species at rates that keep the milkfish population under control and thus maintain the polyculture. Assumptions "* The growth rates of species are constant. "* Variability of amount of eggs laid by species is normally distributed. "* Humans are the only predator of milkfish. "* The channel is not a dosed system; excess population can emigrate to other reef locations. "* The algae are a mix of cyan bacteria and red varieties (this assumption provides more-realistic results). "* Milkfish stop being omnivores when they mature, after which they eat only other animals. "* It takes five years for milkfish to become sexually mature [Luna 2009]. "* An adult milkfish is capable of eating an adult rabbitfish. "* The fish pens currently hold approximately 58.5 million fish. "* Milkfish weigh 500-600 g [Hambrey 19991. "* None of the other five species in the ecosystem model eats starfish. "* Rabbitfish waste has the same composition as milkfish waste. "* The prices found in Task 4 are estimates assumed from solitary sources. "* Giant tiger prawns spawn nightly at a rate of 7.6% to 9% but only half of spawn hatch [Bray and Lawrence 1998]. "* Giant tiger prawns have a mortality rate of 10% to 40% and an average weight of 106 g [Bray and Lawrence 1998]. "* Rabbitfish double in population every 1.4 to 4.4 years