2011 to know the status of the commercially important fishes with emphasis on the endemic freshwater sardine, Sardinella tawilis. Results of the fish landed catch survey in 11 coastal towns of the lake showed a decreasing fish harvest in the open fisheries from 1,420 MT to 460 MT in 1996 to 2011. Inventory of fisherfolk, boat, and gear also decreased to 16%, 7%, and 39%, respectively from 1998 to 2011. The most dominant gear is gill net which is about 53% of the total gear used in the lake with a declining catch per unit effort (CPUE) of 11kg/day to 4 kg/day from 1997 to 2011. Active gear such as motorized push net, ring net, and beach seine also operated in the lake with a CPUE ranging from 48 kg/day to 2,504 kg/day. There were 43 fish species identified in which S. tawilis dominated the catch for the last decade. However, its harvest also declined from 744 to 71 mt in 1996 to 2011. The presence of alien species such as jaguar fish, pangasius, and black-chinned tilapia amplified in 2009. Population parameters of S. tawilis from 2009 to 2011 were estimated using the FiSAT (FAO-ICLARM Stock Assessment Tool) software. The analysis of length frequency data showed an estimated L ∞ of 15.40 to 16.36 cm and K value ranged from 0.53 to 0.73. The total mortality (Z) ranged from 3.01 to 5.03, natural mortality (M) from 1.44 to 1.75, fishing mortality (F) from 1.57 to 3.28 and exploitation rate (E) from 0.52 to 0.65. The high values of fishing mortality and exploitation rates indicate unsustainable fishing practices. Conservation and management measures of the fishery resources in the lake were recommended for appropriate action of the Protected Area Management Board (PAMB).
As part of the conservation efforts to address the declining population of the only freshwater Sardinella (Family Clupeidae) endemic to Lake Taal, a two-year study was conducted to determine the possible spawning grounds of Sardinella tawilis (Herre, 1927) by identifying the spatial and temporal distribution of its larvae. Fish larval samples were sorted from ichthyoplankton samples collected monthly in selected sampling stations in the lake. The morphologically identified Clupeidae larvae were determined to be S. tawilis genetically. They appeared only during March to May, with maximum abundance reaching from 700 to 1,700 ind 100m-3 during April 2015. Among the 10 water, 5 weather, and 11 biological parameters analyzed using Redundancy Analysis (RDA), temperature and other weather parameters largely influenced the temporal distribution of tawilis larvae. In terms of spatial distribution, the stations on the eastern bay of the lake showed an abundant and consistent presence of tawilis larvae for two years. Other stations which showed the presence of tawilis larvae include the southern portion of the lake, as well as in stations south to southwest area of Volcano Island. The seasonal and site-specific occurrence of tawilis larvae confirmed its spawning season and potential spawning grounds, which can serve as a scientific basis in the establishment of a Tawilis Reserve Area, as stipulated in the Unified Rules and Regulations for Fisheries in the Taal Volcano Protected Landscape Management Plan (TVPL-MP 2011).
Lake Taal is a source of livelihood and provides for more than 2,000 sustenance fisherfolk. Fish production of the open water fisheries has dwindled over the years with the continuous decline of fish catch, which can be attributed to unsustainable fishing practices such as illegal fishing, overfishing, pollution, and the expansion of aquaculture activities in the lake. Women, as a sector, constitute almost one half of the economically active population in Lake Taal. Men and women performed different roles at different stages of fish capture or fish culture. In terms of their economic and social value, the participation of women in pre- and post-production activities are significant. This study assessed the level of gender participation in the fisheries sector of Lake Taal. Specifically, it determined the roles of men and women in the different fishing activities and described the fisherfolk’s socioeconomic profile. A total of 407 randomly selected respondents were interviewed in 11 barangays from eight municipalities in Lake Taal, represented by 54% male and 46% female, consisting of 214 fishers, 76 fish vendors, four processors, 51 helpers, and 62 fish cage or fish pond owners, managers, and caretakers. Profiling of the socioeconomic status was done to assess families’ living conditions and constructed primary data based on household’s present roles, activities, responsibilities, access to and control over resources, problems, and constraints of men and women. The roles of both men and women in fisheries were categorized into three sectors: capture, post-harvest, and aquaculture.
This study evaluated the growth and cost efficiency of tilapia (Oreochromis niloticus) and milkfish (Chanos chanos) fed three feed types used in cage farming in Taal Lake, Batangas, Philippines to serve as baseline information for cage aquaculture regulations. O. niloticus and C. chanos were reared in net cages fed three feed treatments: extruded floating feed (EFF), slow-sinking feed (SSF), and sinking feed (SF). Growth performance, feed conversion ratio (FCR), yield, and cost efficiency were compared at harvest. Results of the study showed that EFF had significantly higher mean weight gain, absolute growth and specific growth rate, biomass harvest, percentage good size fish, and FCR than SF in both O. niloticus and C. chanos (P<0.05), but had no significant difference with SSF in terms of growth parameters (P>0.05). FCR and biomass harvest were significantly higher in EFF than SF in O. niloticus (P<0.05) but were not statistically different in C. chanos (P>0.05). Survival rate was not significantly different among feed types (P>0.05) in both species. Net profit was significantly higher in EFF than the other feed types (P<0.05). At the same volume of fish production in the lake, the use of extruded floating feeds in cages lessened the feed cost by 17.91-29.44% for higher net returns and decreased feeds use by 19.64-30.0%, which could minimize negative impacts on the lake water environment. The results of the study revealed the comparative advantage of floating feeds over slow-sinking feeds and sinking feeds and is therefore recommended as the ideal feed type for cage farming in the lake.
Arius maculatus, commonly known as spotted catfish and locally known as Tambangongo, has a great potential as an aquaculture species, but there is very limited information known for the stocks in Panguil Bay. This study aimed to assess the wild stocks of A.maculatus, and make an inventory of the fishing boat and gears in two stations in Panguil Bay, namely: Tangub, Misamis Occidental and Baroy, Lanao del Norte. Length frequencies were analyzed to provide estimates of growth, mortality, exploitation ratio, and recruitment pulse of A. maculatus in the bay. A total of 589 boats (324 motorized boats and 265 non-motorized boats) were recorded from the sites. There were 473 units of 15 types of fishing gear used in the sites and 6 types of these were only used in catching A. maculatus. A total of 3,259 specimens were collected for 12 months from the sites. The aquatic habitat of A. maculatus from the two sites was characterized by a pH range of 7.9-8.1, temperature of 28.5-29.1°C, salinity of 13.31-15.9 ppt, dissolved oxygen levels of 4.0-5.41 ppm, and total suspended solid values of 0.1-0.6 g/L. Reproductive biology analysis indicates that eggs start to mature from October to December, then spawning starts from January to March, and the fish fry recruitment starts in April and May. A. maculatus can grow up to 98.95 cm with an asymptotic length of 98.86 cm (K value = 0.35) equivalent to asymptotic weigth of 8,750 g. Mortality Z = 0.99, with natural mortality M = 0.67 and fishing mortality F = 0.33. This study revealed that A. maculatus in Panguil Bay is not over-exploited since the exploitation rate (E = 0.33) is minimal and large individuals can still be collected from the field.
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