Translocation of the clupeid Sardinella tawilis to another lake in the Philippines: A proposal and ecological considerations
Share
Abstract
The dwindling commercial catch of Sardinella tawilis (Clupeidae), locally known as 'tawilis', reported in recent years by local fisher folk in Lake Taal, Batangas, Philippines, could be a result of the interaction of factors such as over fishing, destructive fish-capture techniques, changes in water quality, and others. Like the rest of the handful of endemic freshwater fish species in the Philippines, S. tawilis is threatened with depletion of its stocks, if not with extinction in the near future. A conservation strategy that could be considered is the translocation of 'tawilis' to another lake in the Philippines, whose ecological features closely resemble those of Lake Taal and where 'tawilis' would receive socio-economic and cultural acceptability. Cases of clupeid introductions - natural and man-made, successes and failures - are presented from published literature. Special attention is given to the case of a well-planned trans-country (Thailand-to-Indonesia) attempt to introduce a clupeid fish. The broader questions of biodiversity, endemicity, conservation, and fish community structure in Lake Taal (and elsewhere) must be underpinned by sound basic taxonomy and ecology.
Suggested Citation
Mamaril, A. C. (2001). Translocation of the clupeid Sardinella tawilis to another lake in the Philippines: A proposal and ecological considerations. In C. B. Santiago, M. L. Cuvin-Aralar, & Z. U. Basiao (Eds.), Conservation and Ecological Management of Philippine Lakes in Relation to Fisheries and Aquaculture (pp. 133-147). Southeast Asian Fisheries Development Center, Aquaculture Department, lloilo, Philippines; Los Baños, Laguna, Philippines: Philippine Council for Aquatic and Marine Research and Development (PCAMRD), Department of Science and Technology; Quezon City, Philippines: Bureau of Fisheries and Aquatic Resources (BFAR), Department of Agriculture, Quezon City, Philippines.
Type
Conference paperISBN
9718511539Related items
Showing items related by title, author, creator and subject.
-
The ichthyofauna of Lake Manguao, Taytay, Palawan, Philippines with special reference to endemic species
(Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA), 2005)Lake Manguao is the only freshwater lake in mainland Palawan. It is special because it has no surface outflow that connects it to the sea. The fish fauna of Lake Manguao was studied during three sampling events in June, September, and November 2002. Seven types of fishing gears were used and a total of eight stations were sampled representing both the littoral and open water zones of the lake. The study assessed whether the unique fish fauna first catalogued by Day (1914) and later by Davies and Green (1990) is still present in the lake after the introduction of Oreochromis niloticus (Nile tilapia) in 1992. The study also looked into the local uses of the lake fishes. A total of 12 fish species from ten genera belonging to eight families including Anabantidae, Channidae, Cichlidae, Clariidae, Cyprinidae, Eleotridae, Hemiramphidae, and Siluridae were collected from the lake. In addition to the species previously accounted for by earlier researchers, two new fish species were recorded: Clarias macrocephalus, a native catfish of the Philippines; and Puntius sp., a possibly undescribed lake-endemic cyprinid. The study also provides answer to the argument brought up by Davies and Green (1990) stating that there is only one endemic species of Puntius in the lake contrary to the accounts of Day (1914) and Herre (1924) who both recognized two endemic Puntius species in Lake Manguao. This study also confirmed the assumption made by Haig (1950) that the lake-endemic silurid catfish described by Herre in 1924 as Penesilurus palavanensis is just a junior synonym of Hito taytayensis, a silurid catfish whose distribution is only confined to Palawan. Results of the study revealed that the unique fish community of the lake still prevails 10 years after the introduction of O. niloticus. However, the fate of the native and endemic fishes in the near future should be a priority because most of the local fisherfolks claimed that the populations of some native and endemic species, some of which are listed as vulnerable under IUCN, have declined several years after O. niloticus was introduced. -
The decline of native fishes and fisheries and the rise of aquaculture in lakes and rivers in the Philippines
Bagarinao, Teodora
(Aquaculture Department, Southeast Asian Fisheries Development Center; Philippine Council for Aquatic and Marine Research and Development (PCAMRD), Department of Science and Technology; Bureau of Fisheries and Aquatic Resources, 2001)
This paper reviews historical and recent data on biodiversity, fisheries, exotic fishes, and aquaculture in Philippine lakes and rivers. The country's lakes and rivers are poor in primary freshwater fishes because the Philippines' only connection with the Asian mainland had been through land bridges between Borneo, the Sulu islands, Mindanao, Palawan and Mindoro - in which islands endemic carps have evolved. Philippine lakes and rivers instead have secondary freshwater fishes such as gobies, migratory marine fishes such as mullets, and some snails, clams, and prawns. Most lakes and rivers have been severely degraded and their biodiversity reduced by siltation, pollution, overfishing, and the establishment of exotic fishes from other countries or elsewhere in the country. Many fishes first described in the Philippines in 1910-1940 by Seale, Herre, and Filipino ichthyologists have not been collected in recent years. The Laguna de Bay fishery in the early 1960s was largely dependent on the 'ayungin' Therapon plumbeus, 'biyang puti' Glossogobius giurus, and the 'kanduli' Arius manilensis that together comprised 95% of the annual 83,000 mt; another 19,000 mt came from shrimps and 245,000 mt from snails. Fishing and snail-dredging were so intense that catches declined and the whole lake fishery collapsed around 1970. After the collapse, the primary production of the lake increased and milkfish and tilapia became natural choices for aquaculture. Lake Lanao became famous for its species flock of 18 endemic carps, but these are now extinct, except perhaps two species. In 1963, these carps contributed 981 mt to the fishery, other native fishes 269 mt, shrimps and snails 257 mt, and introduced fishes 479 mt. Twenty years later, endemic carps have made up only 92 mt, native fishes 141 mt, shrimps and snails 164 mt, and introduced fishes 312 mt of the harvest from the lake. The 'kadurog' G. giurus, probably stocked in the lake with milkfish larvae in 1955, proliferated in the 1960s and apparently drove the endemic carps to extinction. The 'katolong' Hypseleotris agilis was first seen in the lake in 1977 and has since outcompeted the 'kadurog'. In Lakes Taal and Naujan, migratory marine fishes have been caught by fish corrals set across the outlets, but the catch along Pansipit River has fallen since the turn of the century and that in Butas River fell from 62 mt in 1977 to 17 mt in 1983. Catches of the endemic sardine Harengula tawilis in Lake Taal fluctuated between 4,400 mt in 1983 to 11,300 mt in 1990 and 1,400 mt in 1994. Cage culture of tilapia and milkfish has been going on in Lake Taal for 10 years. In Lakes Buhi and Bato, the endemic 'sinarapan' Mistichthys luzonensis almost disappeared due to fine-net fishing and tilapia stocking; catches have been 50-90 mt in 1983-93 but zero in 1994. -
Series: Summary of Proceedings No. 1/2013;
Fishery resource assessment of Taal Lake, Batangas, Philippines
(PCAARRD-DOST, 2013)An assessment of fishery resources of Taal Lake was conducted from January to December of 2010. Fish landed catch survey was done in major landing sites of 11 coastal towns around the lake. Sampling was done 20 days a month during peak landing time at 2 days interval. A participatory approach was done by training and hiring fisherfolk leaders to be the data enumerators of their respective towns. A survey form was used to gather the number of fishermen, boats and gears, catch/species composition, volume of catch, gears used, and fishing effort. A total of 1,054 fisherfolk was recorded in Taal Lake. Inventory of the fishing gear listed a total of 2,084 units of 15 different types of fishing gears used in the lake. Gill net was the most dominant gear with 1,258 units or about 60% of the total gears operating in the lake. Three active gears were identified namely, beach seine, motorized push net, and ring net. The average catch per unit effort of gill net was 6.6kg/day while beach seine, motorized push net, and ring net were 26 kg/day, 544 kg/day and 30 kg/day, respectively. There were 1,484 units of boat operating in the lake, of which 1,110 were motorized, 168 non-motorized, and 206 bamboo raft. Previous data showed that total fish production from 1996 to 2000 has declined from 1,420 mt to 882 mt. The highest catch was 1,672 mt in 1998. In 2010, the total production was 273.62 mt, a reduction of 69.7% from the 1998 production. A total of 47 species were recorded comprising of 38 finfishes, four crustaceans, three mollusks, and two reptiles. Of the finfishes caught, four were endemic, 10 introduced and 24 migratory species. The major fishes caught in the lake were Sardinella tawilis, 39.2%, Chanos chanos (26.2%), Oreochromis niloticus (10.8%), Parachromis managuensis (4.8%), and Glossogobius guirus (3.2%). New record of introduced species include pangasius (Pangasianodon hypopthalmus), jaguar fish (Parachromis managuensis), bighead carp (Aristicthys nobilis), red pacu (Macropopum colossoma), janitor fish (Pterygoplichthys disjunctivus), and freshwater turtle (Pelodiscus sinensis).
