The optimum protein-to-energy (P/E) ratio for juvenile sea bass (body weight, 1.34 ± 0.01 g) was determined using practical diets in a 3 × 3 factorial experiment. Three protein levels (35, 42.5 or 50%) and three lipid levels (5, 10 or 15%) at a fixed carbohydrate level of 20% were tested. P/E ratios of the diets ranged from 104 to 157 mg protein/kcal. The fish were reared for 54 days in 60-liter flow-through tanks with seawater at 32 p.p.t. and 29 °C. Fish fed the diet containing 50% protein and 15% lipid (P/E ratio of 125 mg/kcal) showed the highest weight gain and specific growth rate. Those fed the diet with 42.5% protein and 10% lipid (P/E ratio of 128 mg/kcal) showed comparable growth rate and significantly better condition factor, protein efficiency ratio and apparent protein retention. Fish given diets containing 35% protein showed the poorest growth. Those fed diets with 5% lipid regardless of the protein content showed abnormal reddening of the fins, indicating essential fatty acid deficiency. Body fat increased with fat content of the diet and was inversely related to moisture. Fish given the diet containing 35% protein and 5% fat had the lowest body fat content and the highest ash and water content. The diet containing 42.5% protein and 10% lipid with P/E ratio of 128 mg protein/kcal was found to be optimum for juvenile seabass under the experimental conditions used in the study.

Penaeus monodon stocked in ponds at 8000/ha were fed four types of farm-made feeds starting on day 16 of a 4-month culture period. The feeds were golden apple snail alone or in combination with cooked cassava or maize, or maize only. Mixed feeds resulted in significantly higher production, growth, and better size-frequency distribution of shrimp. Survival (88–99%) was not significantly different among the treatments. Maize alone or snails alone were inadequate. Presumably, the high amount of carbohydrate in cassava (92%) or maize (87%) provided the needed energy, and the high protein content of golden snail (54%) was available for growth. The fatty acid profile of the golden snail shows that it is a good source of 18:2n-6, 18:3n-3, and 20:5n-3 which are essential fatty acids for P. monodon. The golden snail, with an essential amino acid index (EAAI) of 0.84, is a useful alternative source of protein for tiger shrimp. Feeding shrimps with golden snails and cassava yielded the highest net income (P48797/ha-crop) and return on investment (ROI = 206%) better than feeding with maize alone (net income = P23190/ha-crop; ROI = 120%), an industry practice. If shrimp farmers use golden snails as direct feed or as a feed ingredient, the problem of snail infestation in ricefields may be reduced. Snails will no longer be viewed as pests but rather as a resource which has economic value.

The effect of cortisol and thyroid hormones on the activity of mitochondrion-rich (MR) cells in the yolk-sac membrane of tilapia (Oreochromis mossambicus) embryos and larvae was investigated. MR cells were identified by the fluorescent mitochondrial stain DASPEI. Yolk-sac membranes from 4-day-old embryos in fresh water (FW) were incubated for 24 h in medium supplemented with cortisol, thyroxine (T₄), or triiodothyronine (T₃). Treatment with cortisol at 0.1 μ/ml and higher significantly increased the population of MR cells and the intensity of fluorescence compared with the control, whereas MR cell size was not affected. Treatments with T₄ and T₃ did not affect MR cell density, size, or intensity of fluorescence. Four-day-old embryos in FW were immersed for 10 days in FW supplemented with cortisol, T₄, or T₃. A significant increase in MR cell size was observed starting on day 3 after treatment with 100 μ/ml cortisol. Treatment with lower doses of cortisol produced increases in the cell size on later days. Density of MR cells was significantly increased only on day 9. Treatment with T₄ produced inconsistent results. Treatment with T₃ did not affect MR cell size or density at any time. None of the three hormones affected the intensity of fluorescence of MR cells. The stimulatory activity of cortisol on MR cells in the yolk-sac membrane suggests that cortisol, present in the yolk of tilapia embryos and larvae, may be involved in osmoregulation during the early life stages of fish.

This paper presents the first substantive data on sea turtles in the northeastern Sulu Sea. Working with fishers and government, the Southeast Asian Fisheries Development Center (SEAFDEC FishWorld) documented 109 juvenile and adult sea turtles captured or stranded around Panay and Guimaras Islands, Philippines from 2001 to mid- 2011. These included 65 Green Turtles (Chelonia mydas), 15 Hawksbill Turtles (Eretmochelys imbricata), 24 Olive Ridley Turtles (Lepidochelys olivacea), three Leatherback Turtles (Dermochelys coriacea), and two Loggerhead Turtles (Caretta caretta). From the four fishing villages within 1 km of FishWorld came 29 Green Turtles, eight Olive Ridleys, and one specimen each of the three other species. Approximately 77% of the Green Turtles were caught in nearshore fish corrals, mostly between October and May; whereas, 75% of the Olive Ridley Turtles were caught in offshore gill nets and long lines between April and October. Seventy-nine captured turtles were released, 73 of them with inconel flipper tags. Several turtles died from entanglement, serious injuries, slaughter for market, or diseases. An Olive Ridley Turtle and three Green Turtles were seen nesting at three beaches in southern and western Panay. Nesting of Hawksbill Turtles has been recorded at secluded beaches in Lawi, Guimaras about every three years; several batches of hatchlings have been raised by local residents before being released. Size-specific growth rates of Green Turtles and Hawksbill Turtles were highest among post-hatchlings and decreased sharply with size among juveniles and adults.

Juveniles of the giant tiger prawn, Penaeus monodon, were exposed for 10 days to 1 mg/l copper, lead, iron or calcium in order to investigate the formation and accumulation of metal granules in major soft tissues as well as their excretion from the body. Metal deposition was investigated by histochemistry and electron microscopy in the hepatopancreas and surrounding organs and tissues like the stomach, midgut, anterior midgut caecum, thoracal antennal gland extensions, haematopoietic tissue, and interspersed musculature, connective tissue and pigment tissue. The abundance of metal granules varied greatly between the metals and the tissues. Iron and calcium deposits were found in none of the tissues investigated. Copper granules were accumulated in high quantity in the hepatopancreas tubules, were scarce in the antechamber of the hepatopancreas, the anterior midgut and the anterior midgut caecum, and were lacking in the other tissues. The amount and size of copper granules increased along the hepatopancreas tubules in accordance with the cells' age. The granules were released by discharge of senescent hepatopancreas cells in the antechamber region and were added to the faeces. Lead granules were primarily found in the thoracal extensions of the antennal gland. In the hepatopancreas they occurred only in very small quantities, and in the other organs and tissues they were absent. In the antennal gland, the lead granules were individually discharged into the gland lumen by apocrine secretion and excreted with the urine. The observed ability of Penaeus monodon to detoxify and remove metals like copper and lead by granule formation and excretion and to prevent other metals like iron from entrance into major soft tissues corroborate that decapods are no suitable organisms for a long-term biomonitoring of heavy metal pollution.

Nifurpirinol (trade name Furanace and originally known as P-7138), is a nitrofuran derivative synthesized by the Dainippon Pharmaceutical Co. Ltd., Japan, and was developed exclusively as a broad-spectrum antibiotic for fish and other aquatic organisms (Shimizu and Takase 1967). It has been shown to have bactericidal and fungicidal action in vitro and in vivo (Shimizu and Takase 1967; Amend and Ross 1970; Pearse et al. 1974; Mitchell and Plumb 1980), and was used because of its excellent potential in controlling prawn diseases (Delves-Broughton 1974; Gacutan and Llobrera 1977). Milkfish (Chanos chanos Forsskal) is a widely-reared species and a very important aquaculture food crop in most parts of Southeast Asia. Thus, it was the logical choice as test animal for investigating the LC50 toxicity levels of nifurpirinol (6-hydroxymethyl-2-[2-(5-nitro-2-furyl) vinyl] pyridine) after 96 hr exposure. Changes in the normal gill architecture of milkfish after exposure to the drug were also studied (Tamse et al., in preparation).

The levels of estradiol-17β, and progesterone in the hemolymph, ovaries and hepatopancreas, in relation to the vitellogenin levels of captive female Penaeus monodon, were determined during the gametogenic cycle. Estradiol in the hemolymph was detected in fully mature shrimps (Stage 5) only. The ovarian estradiol levels were quite variable but showed no significant differences in the mature (Stages 4 and 5) and spent stage (Stage 6). In the hepatopancreas, a peak in estradiol level was noted in mature shrimps (Stage 5). The progesterone levels in the hemolymph were high in shrimps with mature ovaries (Stages 4 and 5) while those with immature ovaries (Stages 2, 3 and spent) were low or undetectable. The progesterone levels in both ovaries and hepatopancreas were significantly high in mature shrimps. The vitellogenin levels increased simultaneously with ovarian development and reached maximum levels during the final stage of vitellogenesis. A decrease in levels was observed after egg release. The correlation between the levels of progesterone and vitellogenin may indicate a positive effect of this steroid on vitellogenin production.

Lethal toxicity tests of ammonia at different pH levels (7, 7.5, 8, and 8.5) and its effect on survival and growth of the early larval stages of Penaeus monodon were determined. An increase in ammonia toxicity when the water pH increased was revealed in 96 h toxicity tests. Estimated LT50 decreased from 101.09 to 25.16 h for protozoea exposed to 8 ppm ammonia, from 115.79 to 11.26 h for mysis exposed to 24 ppm, and from 51.41 to 22.58 h for PL exposed to 52 ppm ammonia with increase in pH levels. The effect of 3 and 6 ppm ammonia levels at pH levels of 7.0, 7.5, 8.0 and 8.5 on the survival and growth of P. monodon larvae and postlarvae was also investigated in a 16-day sublethal toxicity test. Results indicated that ammonia at 3 and 6 ppm affects both survival and growth of shrimp. Survival was decreased by 27% in 3 ppm and by 48% in 6 ppm ammonia, while growth was reduced by 4.4% in 3 ppm and by 6.5% in 6 ppm ammonia. Increasing pH of the rearing water resulted in significantly lower survival in protozoea, mysis, and postlarval stages. No interactive effect of pH and ammonia was detected.

The comparative morphology of the foregut during development from embryonic larva to adult in Cherux quadricarinatus was examined by light and scanning electron microscopy. Major ontogenetic changes occurred in the gastric mill dentition in terms of denticle shape, appearance of vertical ridges in the lateral teeth, roughness of masticating surfaces, degree of sclerotization and proportional sizes of the median tooth components. Natural food types appropriate for the various life history stages during artificial rearing of C. quadricarinatus may be inferred from the morphology of the gastric mill dentition of those stages. Cardiopyloric valves and the gland filter appeared prior to development of functional gastric mill teeth. Compared with the foregut of adult astacid crayfish, that of adult C. quadricarinatus shows differences in the ventral cardiopyloric valve, pyloric funnel and lateral valves.

One-day old sea bass larvae (0.93-2.03 mm total length, 0.94-1.00 mg wet body weight) were stocked at a density of 30 larvae per liter in nine 250 l capacity fiberglass tanks. Fish were reared for 26 days on three different feeding regimes using Brachionus plicatiilis, Artemia salina and Moina macrocopa as live foods. Delaying feeding of Artemia nauplii until day 15 resulted in slower larvae growth rates compared with fish fed Artemia starting on day 10. Partial replacement of Artemia nauplii by Moina starting on day 17 showed a marked increase in larval growth over the delayed Artemia treatment. Percent survival of larvae amongst all three treatments did not vary significantly.