Three new records of mysids (Crustacea: Mysidacea) from the northern Arabian Sea

This paper with the systematic study of three species of mysids, collected by R/V "Dr. Fridtjof Nansen", which are new to the northern Arabian Sea. The three species described and illustrated are: Siriella affinis Hansen, Afromysis macropsis Tattersal and Acanthomysis quadrispinosa Nouvel.

Records of Oxycephalid amphipods (Crustacea) from Pakistan

Members of the family Oxycephalidae are quite common in the offshore waters of Pakistan, but no previous attempt has been made to study them. Nine species belonging to six genera are recorded from Pakistan waters (22°09′ to 25°21′N and 61°35′ to 67°55′E). The material was taken by R/V Dr. Fridtjof Nansen, during 1977. A descriptive account along with identification key to the genera is provided.

Rotifera from Sri Lanka (Ceylon) 2. Further studies on the Eurotatoria including new records

In the first paper of this series, Chengalath and Fernando (1973) dealt with the genus Lecane from Sri Lanka. In all, twenty five species were recorded, of which seventeen species were new records. Two new species were also described. On the present paper the authors deal with the rest of the Eurotatoria. Again they have found many new records. In all 79 species are described in the present paper of which 47 are new records. The present study is based on the examination of over 300 samples from 135 localities including large and small tanks, ponds of various sizes, rice fields, streams and marshes. The collections cover the whole area of Sri Lanka and were taken during different seasons of the year mainly from 1968-1972.

An analysis of records of gillnet fishing in Pilkington Bay, Lake Victoria

Among the commercially valuable species occurring in Lake Victoria the two endemic species of Tilapia, T. esculenta (Graham) and T. variabilis (Boulenger) still provide the basis for the fishery in many areas, though in some places the non-cichlid species are more important, for example in the Kagera river area where large numbers of Labeo victorianus and Schilbe mystus migrate seasonally into the river. Although certain species show these habitat preferences. Most of the coastline of Lake Victoria supports a wide variety of species, all of which contribute to the commercial fishery. Over the past ten years the East African Fisheries Research Organisation has fished experimentally a number of stations within a radius of fifty miles from Jinja. These stations have been selected so as to cover a variety of habitats which range from sheltered bays to exposed coastlines. The records discussed in this paper are the result of fishing operations carried out in Pilkington Bay over the period December 1954 to November 1956. This series of fishing operations was carried out in an attempt to assess the composition of the fish populations contained in this area. To this end a variety of nets of differing mesh sizes were used. Pilkington Bay is about ten square miles in extent and is an irregular and deep indentation on the north coast of Buvuma Island. It lies within the sleeping siclmess area where fishing by Africans is prohibited. When selecting an experimental fishing ground, it is important to have some idea of the amount of commercial fishing being carried out in the area. Throughout the period of this experiment a few African fishermen were seen operating illegally in the area, but it is unlikely that their efforts greatly affected the results obtained. Pilkington Bay was fished by E.A.F.R.O. in 1949 and 1950 (Lowe McConnell 1956) but since then till the present experiment, fishing in the area has been infrequent.

Rotifera from Sri Lanka (Ceylon) 3. New species and records with a list of Rotifera recorded and their distribution in different habitats from Sri Lanka

In two previous papers, the Eurotatorian fauna of Sri Lanka has been systematically dealt with. Description of 104 species is given in the previous papers. In the present study an additional twenty-two species are described. Of these two are new. The composition of the Sri Lanka Rotifera is discussed in relation to the fauna of other parts of the world. The distribution of the species in different types of habitats is studied on the basis of samples. A complete list of all Rotifera recorded from Sri Lanka so far is given for easy reference. Examples of localities where species were collected are also given.

Two new records of palaemonid prawns from Indian waters

Descriptions with suitable illustrations of two species of palaemonid prawns - Macrobrachium aemulum and Palaemon (Palaemon) concinnus are furnished. M. aemulum has been enjoying an isolated distribution in New Caledonia. It is reported for the first time from India and is therefore a clear case of discontinuous distribution. Studies revealed that M. aemulum is distinct from M. nobilii and the reasons for separating the two species are discussed. New distributional records for P. (P.) concinnus in the south-west coast of India are also given.

Effects of control of C/N ratio by low-cost carbohydrate addition on water quality and pond ecology in freshwater prawn Macrobrachium rosenbergii post-larvae nursing system

An experiment was conducted to evaluate the effects of control of carbon/nitrogen ratio (C/N ratio) by addition of low cost carbohydrate to the water column on water quality and pond ecology in freshwater prawn Macrobrachium rosenbergii post-larvae nursing system. In this experiment, two level of dietary protein 20% and 35% without carbohydrate addition (‘P20' and ‘P35') and with carbohydrate addition (‘P20+CH' and ‘P35+CH') were compared in small ponds of 40 m² area stocked with 20 post-larvae (0.021 ± 0.001g) per m² . Maize flour was used as low cost carbohydrate and applied to the water column followed by the first feeding during the day. The addition of carbohydrate significantly reduced (p< 0.05) ammonia-nitrogen (NH sub(3)-N) and nitrite-nitrogen (NO sub(2) - N) of water in P20 + CH and P35 + CH treatments. It significantly increased (p< 0.05) the total heterotrophic bacteria (THB) population both in water and sediment. Fifty nine genera of plankton were identified belonging to the Bacillariophyceae (11), Chlorophyceae (21), Cyanophyceae (7), Dinophyceae (1), Rotifera (7) and Crustacea (9) without any significant difference (p>0.05) of total phytoplankton and zooplankton among the treatments. Survival rate of prawn was significantly lowest (p<0.05) in P20 and no significant difference (p>0.05) was observed between P20+CH and P35 treatments. Control of C/N ratio by the addition of low-cost carbohydrate to the pond water column benefited the freshwater prawn nursing practices in three ways (1) increased heterotrophic bacterial growth supplying bacterial protein augment the prawn post-larvae growth performances, (2) reduced demand for supplemental feed protein and subsequent reduction in feed cost and (3) reduced toxic NH sub(3)-N and NO sub(2)-N levels in pond nursing system.

Six new records of intertidal polychaetes from Pakistan

This paper describes six species of polychaete worms, which are new records from Pakistan. The species are: Arabella iricolor (Montagu), Capitella capitata (Fabricius), Mesochaetopterus sagittarius (Claparede), Phyllochaetopterus herdmani Willey, Lysidice natalensis Kinberg and Marphysa depressa (Schmarda).