Contributions to the biology of penaeid prawns in Lake Manzalah,Egypt. I. Growth studies and length-weight relationship

Some aspects of the biometrics of Metapenaeus stebbingi, M. monoceros and Penaeus trisulcatus in the brackishwater Lake Manzalah are studied.M. stebbingi dominated the catch all over the lake from December 1966 to June 1967 followed by M. monoceros. The lowest percentage was that of P. trisulcatus which dominated the catch in the northeastern and western parts of the lake in the period September–December. M. monoceros dominated the catch in the northwestern area in the same period. The relation of this distribution to the nature of the lake bottom, chemical composition of the sediment and salinity variations are discussed.Age and growth studies showed that P. trisulcatus has an average monthly growth of 10 mm, and that the fishery is supported by the 0-year class. For M. monoceros an approximate growth of 5 mm/month was observed and it was concluded that the 2-year age group supported the fishery of this species.For M. stebbingi an approximate growth rate of 2–4 mm/month was observed and it was concluded that the I+ and II+ age groups constitute the catch.The growth studies show that P. trisulcatus and M. monoceros spawn during spring, while the peak of the spawning season for M. stebbingi is in the autumn. A close relationship was found between the seasonal variations in the rate of increase of prawn weight and the spawning season.The study included the distribution of the different species and length groups in the different parts of the lake.     

Fertilizing fish ponds: III. Growth of Mugil capito in Egypt by pond fertilization and feeding

The possibility of increasing the growth rate of M. capito fry by using supplemental artificial food and different fertilizers in seven ponds at Mex Experimental Station, Alexandria, is discussed. Growth was indicated by an increase in the length and weight of the fish.The experiment demonstrated different patterns of growth of M. capito. The best growth rates for the adolescent fish are achieved by using supplemental artificial food composed of powdered blood and flour. The next best results are obtained with the cheaper cotton seed cake and rice bran. The increase in the growth rate of the fish in the ponds fertilized with superphosphate and superphosphate plus nitrate, is lower for the 6–12-month-old fish, while it is highest from the fry stage until 6 months of age. Obviously there is a considerable difference between the treated and untreated ponds.     

Derivatives of Salarin A,Salarin C and Tulearin A—Fascaplysinopsis sp. Metabolites

Derivatives of salarin A, salarin C and tulearin A, three new cytotoxic sponge derived nitrogenous macrolides, were prepared and bio-evaluated as inhibitors of K562 leukemia cells. Interesting preliminary SAR (structure activity relationship) information was obtained from the products. The most sensitive functionalities were the 16,17-vinyl epoxide in both salarins, the triacylamino group in salarin A and the oxazole in salarin C (less sensitive). Regioselectivity of reactions was also found for tulearin A.     

Recent N-atom containing compounds from indo-pacific invertebrates

A large variety of unique N-atom containing compounds (alkaloids) without terrestrial counterparts, have been isolated from marine invertebrates, mainly sponges and ascidians. Many of these compounds display interesting biological activities. In this report we present studies on nitrogenous compounds, isolated by our group during the last few years, from Indo-Pacific sponges, one ascidian and one gorgonian. The major part of the review deals with metabolites from the Madagascar sponge Fascaplysinopsis sp., namely, four groups of secondary metabolites, the salarins, tulearins, taumycins and tausalarins.     

Fertilizing fish ponds: II — Growth of Mugil cephalus in Egypt by pond fertilization and feeding

Growth of Mugil cephalus, indicated by increase in length and weight, was studied in seven ponds at Mex Experimental Station, Alexandria. The ponds were treated with different fertilizers and the fish were given supplemental artificial food.Different patterns of growth were studied and compared. The best and cheapest method of increasing the growth of M. cephalus in experimental ponds was to fertilize with superphosphate at a monthly rate of 20 kg. The increase in the growth rate of the fish in ponds receiving superphosphate, and superphosphate plus ammonium nitrate indicated by condition factor values was nearly double that reported by other investigators.