Browsing by Author "Marasigan, Evelyn T."
Growth and survival of milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) larvae reared at the same density in different sized tanks CB Estudillo, MN Duray & ET Marasigan -
The Israeli Journal of Aquaculture-Bamidgeh, 1998 - Society of Israeli Aquaculture and Marine BiotechnologyGrowth and survival of the larvae of milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) in 40, 200 and 500 liter rearing tanks were evaluated at day 14. Milkfish larvae survived better (46%) in 500 l than in 200 l (7%) tanks. All larvae died on day 6 in the 40 l tanks. Growth was better in the 200 l tanks than in the 500 l tanks. The survival rate of the seabass larvae was significantly different in the 40 l (47%), 200 l (61%) and 500 l (75%) tanks, but growth was highest in the 40 l tanks. Rabbitfish larvae had the highest survival in 500 l tanks (7%) but the same growth in all tank sizes. The optimum tank size may vary for different fish species. However, small containers are more convenient to use because they require less manpower, are easily manipulated and more cost- effective.
Salinity tolerance of larvae of the mangrove red snapper (Lutjanus argentimaculatus) during ontogeny Salinity tolerance and the effects of salinity on growth, condition factor and chloride cell (CC) densities were evaluated for Lutjanus argentimaculatus larvae during ontogeny. Tolerance of L. argentimaculatus larvae to abrupt changes of salinity from 32 ppt varied with age. Periods to 50% mortality (LT50) were significantly (P<0.05) longer for 0-day-old larvae than for 7-, 14- and 21-day-old larvae. Tolerance of abrupt salinity change increased remarkably, starting on day 28. Although abrupt transfer to test salinities caused substantial mortalities, L. argentimaculatus larvae, regardless of age (0-, 7-, 14-day-old), showed significantly longer LT50 when abruptly transferred to 8 and 16 ppt than for transfers to 24 and 40 ppt (P<0.05). Growth of L. argentimaculatus larvae at 16, 24, 32 (control) and 40 ppt was not significantly different either at the end of the first rearing phase (days 0–21) or second phase of rearing (days 22–50). Survival was significantly lowest at 40 ppt (4.3%) at the end of first phase of rearing (P<0.05). There were no significant differences in survival rates at the end of the second phase of rearing; however, the condition factor (K) of larvae reared at lower salinities was significantly higher than that of fish at 40 ppt (P<0.05). Gill epithelia of 42- and 50-day-old larvae showed increasing density of CC with increasing salinity.
Book chapterET Marasigan, SL Miag-ao & AE Serrano - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of AgricultureTwo diets were formulated to include 8–14% soybean meal and 9–18% rice bran, 34–40% fish meal, 4–5% mussel meal, and 7–8% Acetes shrimp meal, and 11–13% cod liver oil. Soy bean meal and rice bran were included at 4:1 ratio together to replace 12.5% and 25% of the animal protein sources in the two diets. The two diets were prepared in dry D form and moist M form. The four test diets, D12.5, M12.5, D25, and M25 diets had 40–42% protein and 4,000 kcal/g gross energy. The control diet used was a dry diet with 44% crude protein and 4,260 kcal/g, made with 30% Peruvian fish meal, 8% squid meal, 22% Acetes shrimp meal, 8% cod liver oil, 8% soybean oil, but no plant protein sources. The five diets were fed to juvenile grouper (mean weights ranging from 1.63 ± 0.47 to 2.41 ± 0.91 g) in indoor 400 L concrete tanks (10 fish per tank). After 10 weeks, growth, feed intake, feed conversion ratios (1.2–2.2), and survival (60–80%) of juvenile grouper were not significantly different between the test diets and the control. The carcass composition of the harvested grouper was not significantly different among diets. Protein utilization was best among the fish fed the test diet D12.5. This study showed that soybean meal and rice bran at 4:1 ratio can be included in formulated diets for grouper to replace 12.5% to 25% of the animal protein sources. However, the results for the test diets may also have been due to other factors - the high fish meal content, inclusion of mussel meal, and increase in cod liver oil.