Catalino R. dela Cruz
68 Osmeña St., San Francisco del Monte
Quezon City, Metro Manila, Philippines
Fisheries productivity and enhancements in the country's inland waters were reviewed to determine the successes, the problems and to recommend further enhancements. The limited catch data indicated declining yields in lakes and reservoirs. The fish yields in 18 of the 70 lakes varied from 100–1827 kg/ha; while in four reservoirs, yields were 11–50 kg/ha. Lakes have a higher number of full-time fishermen (74–81%), yields/fisherman (0.7–8.3 t), density of fishermen (5.7–83.3 /km2) and more kinds of fishing gears than reservoirs (33%, 0.4–2.6 t and 0.9–20.0/km2, respectively). In some waters fish stock enhancement is done through fish stocking, establishment of fish sanctuaries and fish pen/cage culture. Improved fishing gears and boats; training, extension and credit support; and alternative sources of livelihood are seen as the means for improving living conditions of fishermen. Politics is seen as interfering in fisheries enhancement. The stocking of tilapia is accepted, because it easily establishes itself. The establishment of self-reproducing populations reduces the stocking cost. Further fish enhancements in inland waters may include adoption of techniques proven successful in other countries, which are suitable to the socio-economic and cultural setting of the country.
The Philippines has about 200,000 ha of lakes and 30,000 ha of reservoirs. The area of reservoirs is expected to increase as more small and large reservoirs are planned for development to satisfy the increasing demand for irrigation water.
Lakes are traditionally a fishery resource and provide livelihood to small-scale fishermen in the surrounding communities. Reservoirs are mostly for power generation and irrigation purposes and fish production in them is considered to be of secondary importance.
The extent of exploiting the fisheries resources of the inland waters varies widely. Some lakes and reservoirs are overfished, while others are underfished. With the increasing demand for food by the rapidly increasing population, ways must be found to improve this situation. In both cases, the fisheries should be enhanced and fishing intensified through established technologies.
Technical strategies, to be successful, should be combined with an appropriate socio-economic setup to suit local conditions. This paper reviews fisheries enhancements implemented in the Philippines' inland waters, and the prevailing social, economic and cultural conditions of the users of the resource. It presents the status of the inland water fisheries and the enhancement activities, programmes and policies, together with the experience gained and problems encountered in implementing them. As there has been no specific project to deal with fisheries enhancement, this review is based on literature, including unpublished reports. The results of discussions with researchers and administrators are also included.
2. RESULTS AND DISCUSSION
The available literature concentrates only on a few lakes and major reservoirs of the country. Of the 70 lakes, Laguna de Bay and Taal lakes were the best studied (Fellizar, 1995; Delos Reyes, 1995; Mercene, 1987; Davies, 1986; Nielsen et al., 1981). Studies on other lakes have had mostly limnological or hydrobiological character: Lake Lanao (Frey, 1969), Naujan Lake (Gracia, 1983), Lakes Bato, Buhi and Baao-Bula (Balite, 1993), Lake Buluan (Yap et al., 1983), Lake Mainit (Lewis, 1973), five lakes in San Pablo City (Mercene, 1976), Taal Lake (Castillo and Gonzales, 1976; Zafaralla, 1995). Other studies were on fisheries surveys of Naujan Lake (Gracia, 1983; Mercene and Alzona, 1984); Bukidnon lakes (Quimpang, 1991); fisheries and yields of Lake Mainit (Manacop, 1937; Pauly et al., 1990); assessment of the Lake Buhi fisheries resource system (Tagarino, 1987); and survey of lakes and reservoirs in Luzon (Darvin et al., 1984).
As to reservoirs, of the 12 hydroelectric reservoirs, seven (Ambuklao, Angat, Binga, Caliraya-Lumot, Magat, Pantabangan and Pulangui IV) have catch data and/or information on limnological characteristics (Balite, 1993; Cruz, 1993; Delos Trinos, 1992; Dela Cruz, 1993).
Overall, the information on fishermen and on socio-economic, cultural and policy aspects of fisheries enhancements are limited to a few lakes and reservoirs. Follow-up evaluation on the effects of supposed enhancements is lacking.
2.1 Fish productivity of inland waters
Table 1 shows the fish yields in some of the 70 lakes in the country, which vary from 100 to 1827 kg/ha. Among the 18 lakes, five are in the yield range of 100–295 kg/ha. The rest are in the range of 461–1827 kg/ha with Lake Buluan as the most productive, followed by Lake Danao (1042 kg/ha).
Fish catches in Laguna de Bay have declined by 75% (from 82,881 t in 1961–63 to 20,728 t in 1973), or from 921 kg/ha in 1961–63 to 246 kg/ha in 1973 (Table 1). After that the yield has slightly improved. The decline was due to a combination of overfishing and pollution. In 1968, the estimated number of fishermen operating in the lake was about 10,000. Ten years later, the number decreased by 50% (Table 1), an indication that capture fishery in the lake became less profitable and many fishermen engaged in other means of livelihood (PCARR, 1980), such as being labourers or caretakers at fish pens and other kinds of jobs. In addition, almost 900 industries are located around the lake, 90% of which are classified as highly polluting, and only 20% have waste treatment devices (Davies, 1988). This might also have had an impact on fish stocks and fish production.
Table 1. Some socio-economic features of natural lakes in the Philippines.
|Sl#||Name of Lake Location||Year of Reference||Area (HA)||Yield Annual (T)||KG/HA||No. of Fishermen||Tons/Fisherman||Source|
|1||Laguna de Bay Laguna||1961–63||90,000||82,881||921||9,756||10.5||8.40||Mercene, 1987; de Silva, 1991|
|1968||90,000||39,055||434||8,700||9.7||4.48||Mercene, 1987; Moreau and de Silva, 1991|
|2||Lanao Mindanao||1984||34,000||10,000||267||3,239||8.50||3.12||Montemayor, 1985;|
|Moreau and de Silva, 1991|
|Batangas||Moreau and de Silva, 1991|
|Surigao del Norte & Agusan del Norte|
|6||Buluan||1984||6,134||11,200||1,827||4,544||74.2||2.50||Yap et al; 1983; Montemayor, 1985; Baluyut, 1987|
|Maguindanao & Sultan Kudarat|
|Camarines Sur & Albay||Baluyut, 1987|
|Camarines Sur||Moreau and de Silva, 1991|
|Zamboanga del Sur||Moreau and de Silva, 1991|
|10||Baao||1980–82||400||600||894||500||74.1||1.20||Moreau and de Silva, 1991|
|Cotabato||Moreau and de Silva, 1991|
|12||Bito Leyte||1984||169||-||-||238||-||-||Montemayor, 1985;|
|Pacijan Is. Cebu||Moreau and de Silva, 1991|
|15||Sebu||1980–84||358||525||547||175||18.2||3.00||Moreau and de Silva, 1991|
|16||Paoay||1982–85||440||118||295||170||43.0||0.69||Moreau and de Silva, 1991|
|Santiago, Agusan del Norte|
|18||Butig||1980–82||50||250||486||100||19.5||2.50||Moreau and de Silva, 1991|
In reservoirs, the catch data also show a declining trend (Table 2). The decline in Ambuklao reservoir between 1988 and 1989 was 84.6% (1.63 to 0.25 t); in Binga, 52% (10.1 to 4.8 t) from 1984 to 1985; Angat, 67.1% (97.0 to 31.9 t) in six years (1987–1992). Magat, the most productive among the reservoirs, declined by 86% (393.5 to 54.8 t) in eight years (1984–1992).
Table 2. Annual catch landings (t) in some Philippines reservoirs. (Source: Balite, 1993; Cruz, 1993; Dela Cruz, 1993; Delos Trinos, 1990).
|YEAR||R E S E R V O I R|
1 Catch from January-June (Cruz, 1993) multiplied by 2.
The reasons behind the decline in catches were: 1) reduced fishing pressure as the number of fishermen decreased and engaged in other means of livelihood; 2) some fishermen or fish buyers were not reporting the high-priced catch or fish were smuggled out of the designated landing places; 3) spilling water carried downstream many fish; 4) unabated reservoir siltation; and 5) reduced fishing period due to inclement weather and unstable water level in reservoirs.
2.2 Socio-economic aspects
2.2.1 Density and fish yield per fisherman
Fishing in inland waters is done by small-scale full- and part-time fishermen. There are more full-time fishermen in the lakes (81% and 74% in Laguna de Bay and Lake Naujan) respectively (Mercene, 1987; Mercene and Alzona, 1984) than in reservoirs (33% in Pantabangan reservoir (Dela Cruz, 1993).
There are more fishermen in lakes than reservoirs (Tables 1 and 3). Table 1 shows that a number of lakes with high yields also have a high density of fishermen. Examples: Lake Buluan, 74.2; Danao, 83.3; Baao, 74.1; Balut, 68.0 fishermen/km2 respectively. These values are much higher than in Laguna de Bay (6.0–10.5 fishermen/km2), where fish yield has significantly declined. On reservoirs, the two highest densities are 20.0 and 10.4 fishermen/km2 for Ambuklao and Pulangui IV, respectively. The yield/fisherman for Pulangui IV is 0.4 t.
Table 3. Catch and number of Fishermen in some major Philippine reservoirs. (Source: Moreau and de Silva, 1991).
|Reservoir||Year||Annual Catch |
|No. of Fishermen||A|
A = yield/fisherman in tons;
1 Balite, 1993;
2 Dela Cruz, 1993;
3 Delos Trinos, 1993;
4 Cruz, 1993 (Annual catch is 2 × 39.2 t catch from January-June 1993).
The yield per fisherman is also higher in lakes than in reservoirs, i.e. 0.7–8.3 and 0.4–2.6 t/fisherman, respectively. This indicates that the lake fishermen are better off than their counterparts in the reservoirs. This also implies that the effectiveness of fishing in many of the lakes is mainly due to the high density of fishermen. The fishermen use largely traditional gears and inferior boats. In Lake Naujan the annual yield/fisherman is 633 kg/ha and the number of fishermen is 15.8/km2. Of the 1742 units of gear used, only 3 out of 9 kinds of gear used are productive and 83% of the boats are non-motorised (Mercene and Alzona, 1984). In Laguna de Bay, where the density of fishermen is lower (6.0–10.5 fishermen/km2), the decline in fish yield can be viewed as a result of stock depletion due to the fishermen's use of relatively better and greater number of gears and boats.
As regards the reservoirs, although the number of fishermen/km2 is less than that on the lakes, one reason for their low yields is the use of traditional gears and non-motorised boats. They are also less skilled and experienced in fishing, since many of them were not fishermen prior to the existence of reservoirs (Dela Cruz, 1993).
2.2.2 Fishing gears
Various kinds of traditional gear are used in fishing. For lakes, fishing gears are more diverse than in reservoirs: gill net, push net, cast net, handline, longline, drag seine, shelters, barriers, corrals, snail dredge, spears, traps, and many others of simple construction. In Laguna de Bay, about 16 different kinds of fishing gear were reported in 1978–80, of which six kinds comprising 5448 units were highly productive (motorised push net, gill net, fish corral, longline, drag seine, and snail dredge gears). Ten types totalling 42,154 units were of a minor type: spears, hoop nets, fish pots, fish traps, and others (Mercene, 1987). In 14 other lakes, 5–10 kinds of gear were used, of which only 2–4 were major gears (Gracia, 1983; Montemayor, 1985).
On reservoirs not all fishermen own fishing gear. For example in Magat, only 56% own gear. Gears used are limited by the National Irrigation Administration (NIA) to gill nets, longlines, cast nets, seines, pole/hand and lines, fish and shrimp traps and spears (Delos Trinos, 1992; Dela Cruz, 1993). Among these, gill nets are most commonly used: 53% in Magat and 68% in Pantabangan, where 79% of the catches in 1992 in the latter were caught by them (Dela Cruz, 1993).
2.3 Fisheries enhancements
The following are the programmes, policies and activities developed to manage and improve the fish productivity of inland waters.
Fish Stocking. This is more commonly done in reservoirs than in lakes. From 1955 up to the present, stocking of various fish species has been done in all the major reservoirs through the efforts of the National Power Corporation (NPC) and the Bureau of Fisheries and Aquatic Resources (BFAR). The frequency of stocking was irregular up to the 1970s. In the 1980s it became almost yearly in some reservoirs (Balite, 1993). Waters with fish pens and cages are “naturally” stocked with fish that escape from them, especially during typhoons.
As shown below, 17 species were stocked during 1955–77, but only six during 1982–89, Oreochromis niloticus being the dominant species, and, between 1990–1992, only O. niloticus was stocked.
|Year||Species stocked in Ambuklao, Angat, Binga and Caliraya reservoirs|
|1955–77||Channa striata, Micropterus salmoides, M. dolumie, Lepomis macrochirus, Oreochromis mossambicus, Datnia plumbeus, Chanos chanos, Glossogobius giurus, Hypophthalmichthys molitrix, Ctenopharyngodon idella, Cyprinus carpio, Aristichthys nobilis, Labeo rohita, Trichogaster pectoralis, Ictalurus punctatus, I. furcatus, I. Catus|
|1982–89||O. niloticus, C. carpio, Chanos chanos, Mugil cephalus, Tilapia zillii, H. Molitrix, carp species|
Fish sanctuary. Sanctuaries have been established in lakes, such as in Laguna de Bay (5000 ha), Taal, Bato, Buhi, Sebu (A. Galicia, pers. comm..) and in reservoirs, such as in Aya reservoir (280 ha), and Pantabangan reservoir. Along with this, stocks are protected through enforcement of fishing net mesh size regulations, and ban on destructive fishing methods (explosives, poison, and electrofishing) (Dela Cruz, 1993).
Fish pen and cage culture. Farming of milkfish (Chanos chanos) in pens in Laguna de Bay began in the late 1960s. By 1973, fish pens in the lake had already covered about 4800 ha (Davies et al., 1988). In the 1970s, cage culture of tilapia (O. niloticus) followed in other lakes: San Pablo City's lakes, Lake Taal, lakes Buhi and Bato. Later on, it expanded to other lakes: Sebu, Paoay, Naujan, and some others (Montemayor, 1985). Cages in reservoirs, particularly Pantabangan and Magat, began in 1982 and 1985, respectively (Delos Trinos, 1992; Dela Cruz, 1993), and are now spreading fast in other reservoirs.
Fish production in inland waters has increased significantly with the introduction of fish pens and cages. These enclosures, including the abandoned and destroyed pens, also serve as a sanctuary for fish species in the open water as fishermen cannot fish close to these structures.
But there are a number of negative social effects as well. Because of the high profitability, many entrepreneurs have engaged in fish pen business. This has created conflicts between the pen/cage operators and capture fishermen over the use of the water. The lack of management and control procedure has enormously increased the area covered by fish pens to 31,000 – 35,000 ha or 30–40% of the lake area in 1983 (Pacoli, 1983; Davies, 1988). Since the cost of constructing a fish pen is high, only rich individuals and corporations can afford to build one. Many pens are illegally built and do not follow the prescribed size limits (5 ha for individuals and 50 ha for corporations). By 1983, 50% of the fish pens exceeded these limits, the largest one being 1200 ha (Davies, 1988). Furthermore, in many cases the fish pens have obstructed the direct access of the subsistence fishermen to fishing grounds. They are limited to narrow passageways in between fish pens and around the structures and dense growth of water hyacinth (Eichhornia crassipes), in order to fish.
In the case of cages, a similar problem has occurred in Lake Taal and Magat reservoir. Cages have proliferated and exceeded the prescribed area limits.
There are several ways one could improve the social and economic status of the fishermen.
Fishing gears and boats. In Laguna de Bay the decline in fish yield is believed to be the result of better gears and a greater number of motorised fishing boats. Eighty-eight percent of fishermen in Laguna de Bay own fishing boats, 64% of which are run by engines with 2–4 cylinders (Mercene, 1987). In Magat and Pantabangan, where the yields are low, 40 to 64% of fishermen own boats, 85–100% of which are non-motorised and used purely for fishing. The few motorised boats are propelled by small 10 hp engine.
For reservoirs that are underfished, improvement or an increase in the number of fishing gears and boats is imperative. For overfished waters, improved fishing gears and boats must be accompanied by sustained technological and biological enhancements to achieve an increase in the fish production.
Credit support. In the early 1980s the Asian Development Bank approved a loan to finance the development of 2500 ha of fish pens in Laguna de Bay. The credit assistance was intended for the subsistence fishermen in the lake in order to improve their socio-economic conditions by engaging in fish pen culture (PCARR, 1980). There is no follow-up report on the results of this financing on the lives of the targeted beneficiaries, but similar credit support would be desirable to enable fishermen to improve their fishing gears and boats.
Fishery extension support. Activities: i) organising fishermen's associations and co-operatives; ii) meetings with fishermen and other watershed occupants; and iii) technical assistance on upland fish farming. This should be carried out on a sustained basis.
Training of fishermen. This was conducted in Pantabangan reservoir during its fisheries developmental stage (Johnson, 1975). BFAR usually conducts similar training upon request by concerned parties. This should also be a continuing activity, especially in new reservoirs.
Upland fish farming. This was initiated in 1988 in Binga and Ambuklao reservoirs to improve the supply of fish and to provide livelihood for the reservoir communities. In 1989, 28 fish ponds (50 – 10,000 m2), were constructed with assistance given to tilapia stocking and culture from the NPC (Balite, 1993). Many of these fish ponds are reportedly still operational.
Although initiated to increase fish supply outside the reservoir area, the development of upland fish farming could be an enhancement and alternative livelihood which can reduce fishing pressure and depletion of stocks in heavily fished reservoirs and lakes.
Politics and consumer species preference are two cultural factors that influence enhancements. Politics has a far-reaching influence on the management of fisheries. Many of the social problems in the fish pens in Laguna de Bay and proliferation of cages in other waters can be attributed to politics. Briefly, influential persons can easily get or do what they want, such as constructing fish pens or cages outside the prescribed area for fish pens. This is seen as having the potential to interfere with fisheries management.
On the choice of species, Filipino consumers have preferred tilapias over the other species. Even in the Muslim area of Mindanao, particularly around Lake Lanao, the fish is abundantly caught in the lake, and is ranked first among the freshwater finfishes in the market (Escudero, 1995). Because of this, the government has provided full support to improving the quality of this fish, particularly O. niloticus.
The improvement of fish production in reservoirs could have been easy if the stocking of other species such as the Chinese and Indian carps along with tilapia had been sustained. This would satisfy the principle in fish stocking, which is to stock a number of species to fill every vacant niche in the water. To stock these species, however, would require considerable investment in establishing and operating hatcheries, as these species would not reproduce in the Philippines' open waters. In this regard, tilapia is considered to be much more suitable for fisheries enhancement in inland waters of the Philippines.
While tilapia is a preferred species in the Philippines, some other countries in the Asian region may be avoiding it. Experience in some reservoirs in southern India indicate that the introduced tilapia (O. mossambicus) now dominates, and hence further stocking of tilapia is not being recommended (Jhingran, 1992).
2.3.4 Policy and administration
The BFAR does not have full control of the fisheries management of inland waters. Lakes are under the jurisdiction of the bordering municipality. The municipality, through its Lake Management Council, issues fishing permits and collects fees from fishermen, enforces fishing regulations, allocates space for fishing and aquaculture, and has some other functions. For Laguna de Bay, the Laguna Lake Development Authority (LLDA) is in charge of the development and management of the lake.
Regarding reservoirs, the NPC develops and implements the fisheries program while the NIA issues fishing permits; designates the area for fishing, sanctuaries, sports, fish pens, cages, and landing points; enforces fishing rules and regulations; and requires registration of all fishing boats and proper marking/labeling of fishing gear (Balite, 1993; Agzalda, 1993; Salumbides, 1993).
For several years, the NPC has focused its fishery development programme on monitoring of fish catches, collection of fees, stocking of commercially-important fish species in the reservoirs, fishery extension and community development, and formulation and implementation of fishing rules and regulations.
At present, the programme focuses on four key areas: (1) formation and strengthening of fishermen's associations to enable them to undertake resource management activities; (2) periodic assessment of the status of fish production, primary productivity, and dynamics of fish populations to determine the carrying capacity of each reservoir, and to effect the most appropriate measures for managing the respective fishery; (3) improving the implementation of regular fishery development activities; and (4) establishment of reservoir fishery-related income-generating activities to generate funds for the various components of the program: fish stock assessment, establishment and protection of fish sanctuaries, fish stocking, management of fishing effort, limnological monitoring and assessment of primary productivity, fishery extension, and fishery legislation. The funding of these activities, however, is not certain since fisheries is just secondary to the agencies' primary functions.
Although the lakes and reservoirs are being managed independently, the BFAR includes inland waters when formulating a national fisheries programme such as the Fisheries Medium-Term (5 Years) Development Plan. However, the implementation of the programme is left to the discretion of the governing agencies.
3. CONCLUSION AND RECOMMENDATIONS
There are several technological and socio-economic areas which could be considered for enhancing fisheries in inland waters in the Philippines.
Better statistical data collection and periodic stock assessment of inland waters to determine their optimum and maximum sustainable yields have been mentioned repeatedly in government programmes as being important and of top priority. The BFAR has obtained foreign funding and will soon begin work in this area.
The introduction of aquaculture (fish pens and cages) in inland waters has significantly increased fish production. This should continue provided the prescribed limit of about 10% of the water area is strictly adhered to.
Development of other aquaculture schemes, such as damming or net-enclosing of coves of inland waters for fish culture (Li et al., 1992), as long as it does not obstruct navigation, should be pursued instead of an outright ban on the idea (Agzalda, 1993; Salumbides, 1993). This will provide alternative livelihood and reduce fishing pressure in overfished waters.
One of the causes of low fish yields in reservoirs is fish loss due to spilling. Installation of fish barriers as is being done in China (Xu, 1992) should be tried by the NPC and BFAR in one or two of the major reservoirs. The BFAR as fishery manager, and the NPC and NIA as reservoir managers should collaborate more closely in exploring and studying other ways of enhancing fisheries. The fish that escape from a reservoir are not lost. They are caught downstream in the irrigation canals. The thousands of kilometres of irrigation canals are a neglected fishery resource that should also be tapped for enhancement
The effects of improved/productive fishing gears and motorised boats, along with sustained fish stocking enhancement, on fish production should be evaluated with possible funding from the government or a foreign funding institution.
Managing small lakes and reservoirs such as fish ponds (with fish hatchery, regular stocking of fish, fertilisation/feeding, and intensive fish harvesting, as being done in China) should be considered where communities or fishermen associations or co-operatives co-manage the fishery resources.
During the planning stage of constructing reservoirs, the plans for fisheries development and management must be clearly indicated. At the onset, the roles and responsibilities of the officials and fishermen organisations of the surrounding communities should be well understood and accepted.
An integral part of inland fisheries management is a good watershed management programme, aimed at curbing pollution and erosion of the watershed. This will minimise siltation, improve the ecology and prolong the existence of lakes and reservoirs.
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