What relationship exists between bangus and tilapia in the fishpond

Early fishponds in the Philippines were concentrated around Manila Bay. . Before discussing the intricacies of the relationships among fry gatherers, A high degree of correlation existed between fry and fingerling prices for the period . hatcheryproduced fry of tilapia (Sarotherodon niloticus) are currently selling for . BIOLOGY 1. What relationship exists between bangus and tilapia in the fishpond ? A. Mutualism B. Commensalism C. Predation D. Competition 2. Heart is. H2 = There exists a significant correlation between the area of a mangrove stand Section 5 discusses these findings in relation to the current literature, any of milkfish (left-hand plot) and other species (i.e. tilapia (Oreochromis niloticus).

The fungus protects the algae from drying and the algae provides nutrition for both through photosynthesis. An example of mutualism is the relationship between flowering plants and the honey bee. The bee benefits from the nectar the flower provides, and the flowering plant benefits from the bee transporting pollen to other plants of the same species to lessen inbreeding. Symbiosis is therefore one form of mutualism. Predation is when one species kills and eats another species.

There is no benefit to the prey. All the benefits go to the predator. Gatherers work in teams, the composition of which depends upon the gear used.

Sagap requires two members to use the net, and an optional third member to carry fry from the net to a basin on shore in which fry are temporarily stored, and to sort out predators and other unwanted species. The attractiveness of the sakag or hudhud and the sweeper comes from their being easily handled by a single gatherer. Bulldozer nets are used primarily at night with lanterns and propelled by bamboo poles by a pair of gatherers at depths of up to three metres. The bulldozer can, therefore, operate beyond the reach of sakag, sagap, and sweepers, all of which are limited to wading depth.

A filter net fixed in creek mouths, and known as saplad or tangab, is most efficient during the twice-monthly high tide periods, when it is often operated 24 hours per day by teams of gatherers.

Rescue Fish From Dried Up Pond And Build Backyard Fish Pond

Three eight member teams who used a single saplad in Antique were able to catch 3 million fry in three days of consecutive high tides in May Of all the gear types, the fixed filter trap saplad or tangab appears to be the most productive per gatherer followed by the bulldozer and then sagap. Fry gatherers, similar to the majority of Philippine smallscale fishermen, have household incomes well below the poverty thresholds established by the Development Academy of the Philippines.

They estimate an average Fry are scooped from the net with a white porcelain basin, against the background of which the eyes of the almost transparent fry can be seen. After being stored temporarily on the beach, fry are either delivered to the concessionaire, to be counted so that the gatherer can be paid for the day's catch, or stored by the gatherer for later sale.

Counting fry is done by a two-member team. One scoops out a few fry with a small bowl or clam shell and calls out the number to the second person, who separates a corresponding number of shells, pebbles, or stones of similar size. After 1, 5, fry have been thus counted, their density can be used as the basis for comparison for the separation of the rest of the catch into lots of similar size. Counting is, therefore, tedious and imprecise when large numbers of fry are involved.

While fry are being temporarily stored in clay pots or plastic basins 50 cm diameter predatory and competitive species are sorted out and discarded. At this early stage of development, it is extremely difficult to distinguish between milkfish fry and the fry of other species. The experienced sorter, however, can pick out an astonishing number of unwanted species, among them the Hawaiian bid-bid or tenpounder Elope hawailensisbuan-buan or tarpon Megalops cyprinoidesand bagaong or grunter Therapon sp.

The bidbid and buan-buan are particularly voracious predators of the young milkfish fry according to gatherers, concessionaires, and pond operators. Unwanted fish are most often discarded on the beach rather than returned to the sea. Concessionaires, once they have purchased the fry, store them for an average of four to five days and it is during this period that feeding usually begins.

The yolk of a boiled egg mixed with water is sufficient to feed approximately 50, fry, or ten basins of fry per day. Two hours after feeding, the water must be changed to avoid contamination from uneaten egg yolk and from excrete. Concessionaires report a further 5. Mortality rates dramatically increase after 15 days' storage despite continued feeding, reaching 20 - 30 per cent after 21 days and 30 - 60 per cent after 30 days.

Consequently, concessionaires make every effort to sell their fry within the first week after capture. The concession arrangement The milkfish fry of the Philippines are essentially an open access common property resource.

The national government has empowered coastal municipalities to grant local "monopsonies"18 to concessionaires in the form of exclusive rights of first purchase of fry. These concessions are generally awarded through a public bidding process. Access to fry gathering, however, is not restricted in any way, as long as the gatherer sells to the designated concessionaire.

Income from the concession licence fee goes directly to the municipality. Because fry grounds are, for the most part, in rural areas, municipalities with fry grounds often have very limited income from other sources. The high value of a concession compared with other components of municipal income has thus resulted in the vast majority of fry grounds in the country being managed under concession licence fees.

what relationship exists between bangus and tilapia in the fishpond

Concessionaires are free to dispose of their fry as they please provided they comply with the government auxiliary invoices required for interregional shipment of fry.

The concession arrangement has a major effect on the incidence of risk in the short run. Because annual bidding for concession rights is held before the fry season begins, the risks of poor catch and windfall profits in good years are very neatly passed from the municipality to the entrepreneur who is awarded the concession.

In the long run, of course, these risks and windfalls would be taken into account by prospective concessionaires before they bid for the concession. Since the municipality collects from a single entity for each fry ground or fry zone, the risk of lost income to the municipal government, due to collection difficulties, is also much reduced.

The system of awarding concessions also provides incentive for the development of new fry grounds, as the initial investment of the concessionaire is protected through a one- to three-year contract of exclusive rights granted him by the municipal council. The concession arrangement severely restricts the level of competition at the early stages after fry catch. However, the existence of smuggling, more prevalent in certain areas, notably Mindanao, provides for a competitive fringe that tempers the abilities of concessionaires to take advantage of their local monopsonies.

There are important issues of economic efficiency and equity involved in an evaluation of the concession arrangement.


The concession licence fee reflects municipal ownership of the resource, and in the long run incorporates the expectations of concessionaires regarding risks and windfall profits from bad and good fry seasons. In the long run, therefore, competitive bidding for the fry concession should result in the municipality receiving the full amount of the resource rent and with gatherers and concessionaires receiving the full amount of their opportunity cost.

Municipalities would have the choice of how to distribute the added benefits obtained from the licence fee. These conclusions can best be seen with the use of a diagram which depicts the widely accepted static fishery economics model based on the Schaefer-type logistic curve from which a sustainable yield curve can be derived.

what relationship exists between bangus and tilapia in the fishpond

Two cases are depicted. If one assumes, on the one hand, that biological overfishing of the fry resource is possible within the relevant range of gathering effort, the shape of the total revenue curve will approximate TR. Although the effect of a concession licence fee on opportunity costs of gatherers and concessionaires and on municipal income the resource rent does not differ in the two cases, there are differences in interpretation regarding the effect on total revenue and hence total catch of fryand the amount of reduction in gathering effort brought about by the concession fee.

In the first case where biological overfishing is possible, open-access equilibrium where total cost TC equals total revenue TR will be reached in the long run when gathering effort equals E1.

At this level, all rent or pure profit from the resource is dissipated and fry gatherers on the average are operating where their average cost including their opportunity cost equals their average revenue. Because the same level of total revenue OA could be earned with a reduced level of gathering effort, the fishery is described as economically inefficient at the open-access equlibrium.

The total revenue curve, TR, assumes biological overfishing can occur with increased gathering effort. Assuming knowledge of historical returns and costs, in the long run, on average this new cost line will be tangential to the total revenue curve.

This is because prospective concessionaires will be willing to bid just high enough so that their expected returns cover their fixed and variable costs, their opportunity costs, and the concession licence fee. This is the same thing as saying that in the long run, the owner of the resource the municipality will be able to extract the maximum resource rent in the form of the concession fee, L which is equal to the maximum difference between total revenue TR and total cost TC.

Effort will be reduced to E2, and total revenue will increase to OC. In terms of the mechanism for reducing effort, however, the concession arrangement is not the same as granting sole ownership rights. A sole owner would limit his own gathering effort to E2 so as to maximize his profits from the fishery. Since access to fry gathering remains open the concessionaires make no direct attempt to restrict entry or to limit purchases how does the desired reduction in gathering effort from E1 to E2 come about and what is the effect upon the opportunity cost, or net return of those gatherers who remain?

Effort is reduced through the pricing mechanism. The imposition of a concession licence fee reduces effort by fry gatherers because the price paid by the concessionaire to gatherers is lower than that which would be received by them under open-access equilibrium.

This is because the concessionaire will want to recover his concession licence fee. Those that remain in fry gathering are those whose individual opportunity cost is equal to or less than the return from fry gathering. Between these logs 1. A 6" 15 cm rubble is also paved on the banks of the canal.

A cross-section of this canal is shown in Fig. This can be seen in the pond layout plan. From the mainline, water is distributed to the mudponds through distribution sumps. Cross-section of a sump can be seen in Fig.

Economics of the Philippine Milkfish Resource System (UNU, , 66 pages): Abstract

From the distribution sump a 9" 23 cm hume pipe is provided to supply water to each pond consisting of a sluice gate to control water coming in and out. In these ponds, there are no separate inlets and outlets. Both are done by same line. This creates more problems in controlling water in the pond, which has earlier been mentioned in this paper. One of the disadvantages of this system is the difficulty of cleaning the underground pipes, in case of blockage inside them. This method cannot therefore, be considered a practical one.


Although suitable steps have been taken after considering the pattern of tidal differences in this area, these have not met with much success. As a result, it is necessary to use water pumps to drain out water from the ponds. Anicuts to control the flow of water to and from the ponds have also been installed. Before this area was developed for the purpose of pond culture, the inhabitants had buried large quantities of coconut husks in the soil.

This has resulted in the soil becoming acidic. These are the coastal areas of Batticaloa-Trincomalee in the east, Negombo in the west, Kalpitiya-Puttalam in the northwest, and Mannar in the north. Of these, Mannar is of great importance as a large stock of milkfish fry enters this area annually. If the location is found suitable, coastal fishpond culture should be developed in this area. This is at present being considered.

This area can also be developed for shrimp culture. Sri Lanka has also made a beginning in the export of shrimp. Here is an area for this industry to develop and make a substantial contribution to the earnings of much-needed foreign exchange. Increasing emphasis on shrimp culture research is being given by the Inland Fisheries Division of the Ministry of Fisheries as there is still room for expansion in this direction. In this consideration, more assistance from countries in the Asian region which have already made much headway will be required.

Recently, a group of Indian scientists researched at the Pitipana Brackishwater Station and reported that conditions are favourable, but due to the lack of resources progress has been slow. Under the circumstances where most of the available resources must of necessity be devoted to development of agriculture in order to achieve self-sufficiency in staple food grains, the State is unable to spend as much as it would wish at present in coastal aquaculture development.

The contribution of the private sector is insufficient. However, it is encouraging to note that the government is aware of the needs and is doing its best to meet them within the available resources.

what relationship exists between bangus and tilapia in the fishpond