Sean Clement Timothy Newlin
Task 5: Maximizing Bioproduce
One of the great difficulties in getting the population of Bolinao and commercial fish farmers to change their milkfish monoculture is to show tangibly how a polyculture would not only improve water quality and coral growth but would also give them greater income. Different propor-tions of the populapropor-tions of species in a polyculture may produce the same water quality, but they are not all equal in economic value. In Task 4 we established estimates for each species in the polyculture. By taking the proportions of these populations from the model in Task 3 and multiply-ing the harvestable population of each by its price from Task 4, we can estimate the revenue from that polyculture. By subtracting the associated input costs for establishing that polyculture, we can compare various poly-culture combinations that meet the desired water quality levels and choose one that ultimately maximizes profit for the fish farmer.
Unfortunately, although we were able to develop such a model, its accu-racy is questionable, because of uncertainties in current and future market prices.
Ultimately, with greater understanding of price changes and levels of pollution at different sites, it would be possible to use our models from Task 3 to determine an optimal harvest strategy is to achieve a unit of water quality. Because water quality is a product of both the level of bacteria and the level of chlorophyll, certain sites may produce more value when the combination of different species is tailored to reduce more of one of those two water contaminants.
Our policy recommendations result from understanding the interac-tions of the various inputs in the polyculture ecosystem. Principles such as inclusion of additional blue mussels to reduce waste levels are helpful to improve initial conditions and reduce waste. Even if the Bolinao people ultimately reject a transition to a polyculture, at the very least they should attempt to improve the water quality of the milkfish pens by using scoops to remove fish waste, which can be recycled and sold to local land farmers.
Simple ideas and principles the value of local community-based education and policing efforts are helpful in improving local quality of life for all Fil-ipinos regardless of the approach they choose. We have highlighted many of these pragmatic practices in a letter addressed to the Pacific Marine Fish-eries Council, which we believe is the best avenue to suggest these ideas to the people in the region.
Conclusion
At first glance, Bolinao appears to have a problem of coral-reef destruc-tion and water-quality deterioradestruc-tion based on the overproducdestruc-tion of a sin-gle type of fish. However, when examined more closely, the real issues are much more personal.
Filipinos are not farming large amounts of milkfish because they seek to destroy their living environment. Their milkfish monoculture practices stem from a growing need for animal protein, of which fish is the most eco-nomical and accessible source for the people in their country to produce.
Fish offers the highest yield of food for raw weight at 65% while simulta-neously requiring the lowest amount of feed input to achieve a kilogram of animal protein. What Bolinao is really struggling to deal with is the very human problem of meeting a growing need for better nutrition and quality of life for their children.
To break this cycle of short-term economic gain at the expense of grad-ual environmental destruction of both accessible water qgrad-uality and coral growth, it must be demonstrated to local farmers that their current milkfish monoculture does more harm than good and that an alternative polycul-ture offers not only a better long-term stability for the environment in the Bolinao region (through improved water quality and coral growth) but also a better economic situation for the local population.
Our solution involves a series of models to explain the past system, the current system, and what a transition in aquaculture practices could create if a future system is adopted. It then focuses on explaining the economic value of the current system and comparing it to the better potential economic value of a polyculture system based on the harvesting of a variety of species, as opposed to the current monoculture focused on harvesting only milkfish.
that reduces bacteria and chlorophyll to better levels while allowing for greater coral growth and economic benefit to the local population through greater revenue from the variety of species harvestable from a polyculture.
At first glance, a monoculture of milkfish seems to be the type of special-ization that offers the highest economic profit for fish farmers by reducing the unit cost of each fish. However, the long-term sustainability cost of the byproduct waste of a milkfish monoculture is not taken into consideration.
Neither is the greater profit that can be obtained through the introduction and harvesting of other species that naturally reduce the economic cost of raising milkfish by reducing the effect of milkfish waste and creating more space to grow additional milkfish. These other species eat the byprod-uct of the milkfish, which provides more harvestable biomass produce per unit of effort. Finally, a variety of combinations of proportions of different populations in a polyculture produce the same level of water quality.
However, not all combinations yield the same economic profit for the farmer, because certain fish offer a better profit than others and can be raised in larger quantities than in other scenarios. While our model was unable to demonstrate multiple scenarios that provide greater economic profit than the current system, such scenarios do exist and could be demonstrated by our model given a larger data set.
We developed simulations to determine the varying water quality based on the conditions of different quantities of the various species and ac-counted for the harvesting rates required in order to make these polycul-tures obtainable. By applying population quantities for polyculture com-binations that achieved the appropriate water quality levels to a formula that produced an profit value for that combination, we could have deter-mined which polyculture could provide the most profit to the fish farmer for the desired level of water quality that would allow for successful coral growth and long term sustainability of the polyculture. Furthermore, this increased profit could then be used in global trade to create a wider variety of diet than would be otherwise available.
Our model could be improved through the use of a more complete data set to improve the ratio of relationship between the species to levels closer to what is observable in nature. A more-developed data set would not fundamentally change any of the relationships among the variables in the models we developed. Additionally, more accurately accounting for the human population in the model, and adjusting the harvesting rate of the milkfish based on this inclusion, would also provide more accurate results than trying to extrapolate what the human population should harvest on a periodic basis in order to bring the ecosystem back into balance. This inclusion of the human population into the growth model of the population of the milkfish is necessary because in our ecosystem humans are the only predator of the milkfish, thus making them a requirement for equilibrium to be achieved.
recent pricing data for the market value and cost inputs of introducing the other species into the commercial fish farms next to the milkfish.
Despite the shortcomings of our models, we were still able to adequately show the economic and environmental benefit to the region by transitioning from a monoculture of milkfish to a polyculture of biological diversity. One of the biggest contributors to changing this system and reducing bacterial waste was the growth of the blue mussel molluscs. Through this process, our models should convince the people of the Bolinao region of the Philip-pines to transition from the current monoculture of raising and harvesting only milkfish to a polyculture where they raise and harvest a wider variety of species to obtain the maximum sustainable yield from the ecosystem.
With this optimal combination, implemented through the introduction of better farming practices and other species of aquatic life, it is possible to achieve a better result for both the environmental and economic quality of life for the Bolinao people over both the short and long term.
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Dr. Edward Swim (MCM/ICM coordinator at West Point) with team members Sean Clement, Timothy Newlin, and Joseph Lucas receiving their ICM certificates.