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close this book Economics of the Philippine Milkfish Resource System (1982)
close this folder IV. The transformation sub-system: cultivation to market size in fishpens
View the document 1. Introduction
View the document 2. Some efficiency measures

1. Introduction

1. Introduction

An alternative method of rearing market-size milkfish entails transformation from fingerlings in bamboo and net enclosures (fig. 33). In contrast to rearing in brackishwater ponds, fishpens are operated in bodies of freshwater, where the operator has much less control over the fishrearing environment. Although the pen concept has resulted in experimental operations in many small lakes in the country, the only large-scale commercial activity is in the shallow 90,000-ha Laguna de Bay, adjacent to Metro Manila (fig. 34). Although Laguna de Bay is a reasonably productive eutrophic lake, it is not as productive as many other tropical lakes, such as Lake George in Uganda.52 In 19701971, the Laguna Lake Development Authority (LLDA) successfully introduced the pen method of fish culture, achieving yields of close to 4 tonnes per hectare per year relying solely on the abundant natural food available in the lake.

By 1973, the fishpen sub-sector was producing annual harvests valued at P77 million from 4,800 ha of fishpens.53 BY early 1976, pen area had grown to over 7,000 ha, and estimated total milkfish production to 47,000 tonnes (table 20): quite remarkable growth for only a seven-year period. The rapid growth in fishpen area in the early 1970s is indicative of the dynamism of the private sector in the Philippine economy and its willingness to take risks with a new venture.

Despite the attractiveness of fishpens to private investors because of the high rate of return on investment that can be achieved, numerous problems have surfaced. These problems relate, on the one hand, to environmental factors beyond the control of fishpen operators, such as the weather, aquatic macrophytes, and plankton blooms that result in fish kills and, on the other hand, to socio-economic factors brought about by the alleged impact of fishpens on the capture fishery that has existed in the lake for centuries. These problems combined to reduce fishpen area in 1976-1977 to approximately 4,000 ha.

Plankton blooms, most probably caused by the enriched inflow from the heavily fertilized rice-fields of Laguna Province and from sewage wastes of urban communities, result in rapid reductions in dissolved oxygen which cause fish kills in several parts of the lake. In 1973, for example, the loss of an estimated 1 million fish was recorded; some owners lost 90 per cent of their stock.53

A typhoon that occurred unseasonably early in 1976 resulted in widespread destruction of fishpens, further discouraging the large number of lawyers, doctors, and even movie stars who had rushed to invest in fishpens after LLDA's success became known. Water hyacinth, driven by high winds, damaged the bamboo and netting materials, allowing large quantities of fish to escape to the delight of the small-scale fishermen living around the lake who then caught them with their gill nets. Similarly, major typhoons occurred in 1978, but the three years since have been characterized by relatively calm weather.

Serious as these risks from typhoons were for the fishpen entrepreneurs involved, socio-economic problems were just as pressing. While fishpen production continued to climb, catch from the lake capture fishery was declining (table 20). The capture fishery had actually been declining continuously since 1963 so it is not possible to ascribe the decline exclusively to the presence of fishpens. However, the initial uncontrolled erection of fishpens in the lake produced conficts with the small-scale fishermen, who claimed that fishpens had reduced their fishing area and in extreme cases had even blocked access to the water. Sabotage of fishpen nets became common, and most fishpens now have guard houses at regular intervals along the perimeter of the pen to guard against these surreptitious acts.

Controlling the location of fishpens of private investors has been a major problem for LLDA. Jurisdictional disputes between LLDA, the Bureau of Fisheries and Aquatic Resources (BFAR), and the municipalities around the lake have only recently been resolved in favour of LLDA, which now has exclusive licensing authority. A 15,000-ha fishpen belt has been designated within which all pens must be located (fig.34).

Laguna de Bay, like any other body of water, has a certain carrying capacity based upon its primary productivity. Delmendo and Gedney53 have made the only estimate of the lake's potential productivity (63,000 - 270,000 tonnes), based on conditions prevailing in 1973. What effect fishpens may have on the lake's productivity is debatable.



Fig. 33. Details of Fishpen Enclosures. Source: See note 53.

Increased stocking of milkfish in pens may even increase carrying capacity if they crop phytoplankton that is left untouched by other species. Construction of fishpens has certainly reduced fishing areas; however, one cannot ascribe the declining capture fishery catch solely to fishpen expansign, since it had been declining for several years before the first fishpens appeared. From 1963 to 1973, while the number of small-scale fishermen increased from 13,000 to 16,000 and shrimp catch increased by 25 per cent, catch of fish from the capture fishery declined by more than 75 per cent, and snail harvest declined by almost 75 per cent. Total production in Laguna de Bay declined from almost 350,000 tonnes in 1963 to only 120,000 tonnes in 1976.57 In part, therefore, declining capture fishery catch is due to overfishing.

While the value of production from the lake increased from P77.2 million in 1968 to P149.1 million in 1973, all of this increase in revenue accrued to the owners of fishpens. The value of the capture fishery (fish, shrimp, and snails) actually declined over the period from P77.2 million to P72.3 million. The decline in value in real terms was even greater. Except on those occasions when milkfish escape from fishpens after typhoons, and are subsequently caught by municipal fishermen, or when fishermen are employed as fishpen labourers, the fishpen business has apparently had little positive impact on the many fishermen living around the lake.58

To deal with the need to involve former small-scale fishermen in more than simply providing labour to fishpen owners, the LLDA has recently embarked on a project with financial support from the Asian Development Bank to develop 2,500 ha of fishpens in 2.5-ha, 5.0-ha, and 10-ha modules that would be managed by former fishing families or groups of families.59 The project has both milkfish and tilapia components, the tilapia to be raised in cages rather than pens. Tilapia cage culture, based primarily on supple mental feeding-in contrast to milkfish in pens, which feed on the lake's natural production-is already practiced by many fishing households. The nutrient flow and detrital production from the lakeside duck farms has undoubtedly aided tilapia production from cages near the shoreline. Participation in the project is limited to families with annual incomes less than P9,000, and the loan to participants carries a 14 per cent interest rate and is payable in five years through deductions from proceeds of sales of milkfish through LLDA.



Fig.34. Laguna de Bay, Showing the Fish Sanctuary and the Fishpen Belt. Source: See note 54.

Three problems, however, must be overcome for the milkfish component of this project to succeed. First, reliable supplies of large quantities of fingerling must be found (the 2,500 ha to be developed will require approximately 75 million milkfish fingerlings annually). Secondly, a way must be found for the small 2.5-5.0-ha modules to remain profitable despite economies of scale that favour larger pen sizes. Finally, the project may experience difficulties in persuading fishermen with low incomes to invest in the capital-intensive fishpens.

Managing the capture fishery to reduce overfishing and allow stocks to recover to produce higher sustainable yields is an alternative approach that might be considered to assist the small-scale fishermen. A second alternative may place added emphasis on tilapia cages with their lower investment requirements, rather than requiring fishermen co-operators in the project to invest in both milkfish pens and tilapia cages concurrently.