Lagenidium scyllae , a marine mastigomycete from the ova and larvae of the mangrove crab, is described and illustrated as new. The fungus grew at a temperature range of 16-42 C, with an optimum at 22.5-31.8 C. It grew well in peptone-yeast-glucose (PYG) broth containing 2-3% NaCl. In PYG-sea water medium, it grew at a pH range of 5-11.

The postlarvae were maintained in 5-l round plastic aquaria and provided with aeration for a 28-day feeding period. Highest survival rate of 100% was obtained when the postlarvae were fed with Diet-B. Growth, in terms of weight and length was highest in postlarvae fed with Kyowa Hakko and mysid feeds. Using T. philippinarum as control, this experiment showed that feeding with Diet-B, Kyowa Hakko and mysid feeds resulted in similar or better growth and survival rates of P. japonicus postlarvae.

This paper discusses present prawn culture practices in the Philippines, as well as the experiments which are conducted at the SEAFDEC Aquaculture Department by reviewing production of fry, production of juveniles in nursery ponds, growing prawn in rearing ponds, and present problems of prawn culture in the Philippines.

The role of hormones in the controlled reproduction of a few test fishes is well documented. However, information on the mechanisms of endocrine regulation of ovulation in cultivated warm-water fishes is very meagre. Hormones, especially the gonadotropic hormones of piscine origin, are increasingly being used in modern aquaculture to produce the seed of many important cultivated fishes. While chorionic gonadotropin and other exogenous mammalian hormones are used in spawning the channel catfish, fish pituitary hormones are usually needed to induce spawning in the difficult-to-spawn Asiatic carps. In mullets, however, either homoplastic pituitary gland or human chorionic gonadotropin (HCG) or a mixture of HCG and a threshold dose of the former is ordinarily injected to precipitate spawning. Of late, semi-purified salmon gonadotropin (SG-G100) has been used to induce spawning in several species of food fishes. While several marine fishes have been artificially bred by administration of hormones, induced spawning of the milkfish, C. chanos has been tried with little success. The milkfish is a widely distributed food fish extensively cultivated in ponds in Southeast Asia. Recently, significant results have been obtained in spawning mature milkfish captured from the wild by hormone injections. The experiments conducted on induced breeding of milkfish leading to the successful fertilization and hatching of milkfish eggs are briefly described.

A total of 2497 milkfish fry were collected in 1976 from nine localities in six countries, viz. India, Thailand, Indonesia, Philippines, Taiwan and Tahiti. Vertebra counts ranged from 40 to 45. The general trend of geographical gradient in vertebral counts in the milkfish was observed to be lower in the west (or otherwise, along continents) and higher in the east (or around oceanic islands). Extremes in the means of vertebral counts by localities were seen in the samples from India with 43.08 and from Tahiti with 43.82. It was suggested that there may be at least four subpopulations among the milkfish throughout the tropical Indo-Pacific waters.

The recognition of individual animals is crucial to many aspects of research. Prawns present unique difficulties in this respect since they molt regularly. Thus almost all tagging and marking methods developed for prawns so far have proven inadequate. Some are lost during molting; others cause injury to the prawns. A new and efficient method has been developed at the Igang Sea Farming Station of the Aquaculture Department. Brass tags measuring 5 mm by 20 mm and numbered consecutively are encircled around the eyestalk like a small bracelet. The prawn is gently held at the base of the carapace by the left hand while the right hand slips the brass tag over the eye. The tag is gently pressed around the eyestalk to prevent its slipping out. All tagging is done under water to avoid stress.

In the present study, no visible differences between the sexes of C. chanos with reference to external features such as colouration, shape of head, snout and operculum, presence of tubercles or nasal pores, length, size and shape as well as any roughness in the various fins, could be found. However, the anal region of the mature milkfish (sabalo) exhibits discernible anatomical differences in the male and female. The male has two main openings visible externally: the anterior anus and the posterior urogenital opening at the tip of the urogenital papilla. The female has three main openings instead of two: the anteriormost anus, followed by the genital pore and the urinary pore located posterior to the genital pore at the tip of the urogenital papilla. Internal examinations were also made on both sexes. In ripe sabalo, it is easier to distinguish the sexes since milk oozes out of the urogenital pore by pressing the abdomen of the ripe male fish. Gravid females are identified by their distended abdomens.

Four different postlarval stages (P₁₁, P₁₅ , P₂₁, and P₂₅) of P. monodon were stocked in suspension nets at the rate of 200 fry/sq m with 3 nets for each postlarval stage. Pond bottom was simulated by filling each net with a 15 cm layer of mud; dried twigs were provided for protection of the fry. Feeding with lablab and determination of temperature, dissolved oxygen, pH, salinity and alkalinity were regularly undertaken. Results show higher survival rates for P₁₅ and P₁₈ compared to the other stages.

The Japanese little-neck clam, Tapes philippinarum, an introduced species in Kaneohe Bay, Oahu, Hawaiian Islands, has a thriving population only in a U5-hectare mud flat after heavy fishing triggered depletion in six other beds within the bay. Monthly gonad examination of the clams suggested that spawning occurs at a low level throughout the year with a peak from January to February. This observation is corroborated by the appearance of new recruits in the monthly sample from April to June and by their presence at low levels at other times of the year. Size-specific fecundity, determined indirectly from differences in the length: dry weight relationships of ripe and spent clams, ranges from 432,000 eggs in a 20-mm clam, increasing exponentially to 1.35 x 10⁶ eggs in a 40-mm clam. Estimates of the population of clams 11 mm and larger, which were 3.09 x 10⁶ in 1970 and 3.4 x 10⁶ in 1972, show a growth of 5 percent per year during the 2-year period; monthly quantitative sampling showed no evidence of population growth after 1972. A survivorship curve obtained from the monthly samples gave a total instantaneous mortality of z = 0.2005. The age-specific mortality agrees with the age-frequency of the empty shells collected from the bed, with a correlation coefficient of 0.9345 with 4 d.f. The condition of the empty shells indicated that 57 percent of the mortality is attributable to crab predation, mainly by Thalamita crenata, which constitutes 70 percent of the experimental crab catch in the clam bed. Sixty percent of the broken shells were 19.5 to 30.4 mm in length; in experiments with predation by T. crenata, 96 percent of those eaten fell within the 14.5 to 30.4 mm size range. The difference between the lower limits of the size ranges can be attributed to the size structure of the clams during the survey period. The experimental population had an artificially maintained size structure. Experimental exclusion of predators over a limited area suggested that crab predation regulates clam size structure but not clam density.

The early growth, yolk and oil globule resorption, early morphological and behavioral de-velopment, and initial feeding of hatchery-raised Lates calcarifer were studied. Based on the developmental events and the energy the reby utilized, the early life history of this species can be broken down into the following five phases: 1) rapid early growth due to rapid yolk resorption (from hatching to about 15 hr after hatching (TAH); 2) morphological differentiation and slowgrowth based on energy from yolk (to about 50 h TAH when the yolk is exhausted); 3) slow growth with initiation of feeding and swimming activities, based on energy from oil globule and from exogenous food (to about 110 h TAH); 4) accelerated growth and effective feeding and swimming based on the same two sources of energy as in the preceding stage (up to about 120-140 h TAH when the oil globule is exhausted); and 5) accelerated growth, effective feeding and swimming and further development based solely on exogenous energy (beyond 140 h TAIT).