• A Comparison of the bacterial flora of surface and sub-surface water of the sea off Ceylon

      De Silva, N.N. (1964)
      Under stable conditions of stratification of the sea, evidence of generic differences of the associated bacterial flora of the water masses has been obtained, between surface and sub-surface water. Gram negative rods, especially pseudomonads and achromobacters were more frequent at the surface. The fermentative and oxidase negative flora was more frequent in sub-surface water. The surface water in general had a greater variety of bacterial types while the sub-surface water had a flora with a greater range of biochemical activity. These results are discussed in relation to the hydrological condition of the water masses and the bacterial flora of freshly caught fish.
    • A Contribution to the limnology of Colombo Lake

      Mendis, A.S. (1964)
      This paper records the results of investigations of plankton, benthic fauna and fish fauna carried out between 1957 and 1963. The standing crop of net plankton in the lake was found to be 249.6 Kg/ha. This plankton is not being fully utilized by the fish fauna in the lake. Stocking the lake with a plankton feeder like Chanos chanos (Forskal) is recommended. The figure of 24.37 Kg/ha obtained for the standing crop of bottom fauna in the lake was comparatively low. This indicates that the bottom fauna is being fully utilized by the fish. The introduction and establishment of Tilapia mossambica (Peters) had not wiped out a single indigenous species of fish from the lake that produces about 2,000 lbs. of fish per acre per year. This can be increased by the introduction of a plankton feeder (Chanos chanos), and by further exploitation of existing stock.
    • A guide to the fisheries of Ceylon

      Fisheries Research Station, Ceylon (1958)
      This bulletin has been written primarily to serve as a handbook to the Indo-Pacific Fisheries Council at its sessions in Colombo during December 1958. It presents an outline of the fishing industry as found in Ceylon today, in non-technical language so that it may also be understood by laymen. The large gaps in our knowledge are brought out in the section on "resources"; the section on "administration" gives an indication of progress made towards solving the problems of the industry, while sections on "fishing methods" and "utilization of catch" will help us to appreciate the handicaps and difficulties of those concerned with the industry. The Government Administration of the fisheries of Ceylon is being assisted to a considerable extent by the generous gifts of machinery and equipment as well as the loan of skilled technical personnel made by other countries through the FAO and the Colombo Plan. The progress made so far has helped to place the industry in a favorable position for further improvements.
    • A guide to the freshwater fauna of Ceylon

      Mendis, A.S.; Fernando, C.H.; Kariyawasam, G.D. (1962)
      Freshwater animals are of importance in the economy of most countries. In recent years the scientific cultivation of freshwater fish for food has been spreading throughout South-East Asia and the Far-East. New and useful species of fish have been introduced into many countries including Ceylon where the older system of trapping any variety of fish that is available is being replaced by scientifically planned management with a view to increasing the production of good quality fish. Considerable quantities of food mainly in the form of fish are being taken from our freshwaters, providing a cheap source of much needed protein in the diet of the villager. More recently large quantities of freshwater fish are being consumed by the urban population.
    • A guide to the freshwater fauna of Ceylon. Supplement 1.

      Fernando, C.H. (1963)
      This is the first of a series consequent to "A guide to the freshwater fauna of Ceylon" by A. S. Mendis and C. H. Fernando, Bull. Fish. Res. Stn. Ceylon No. 12, 160 pp. (1962). The purpose of this series is to make the above-mentioned work more comprehensive. The present supplement is restricted to the Arthropoda.
    • A Guide to the freshwater fauna of Ceylon. Supplement 2

      Fernando, C.H. (1964)
      This is the second supplement to "A guide to the freshwater fauna of Ceylon" by A. S. Mendis and C. H. Fernando, Bull. Fish. Res. Stn., Ceylon, No. 12, 160 pp. (1962). In the present supplement additions and corrections are made in the sections on Protozoa, Annelida and Arthropoda. The sections on Platyhelrainthes and Nematoda have been expanded and the Acanthocephala added. A list of species recorded and the hosts of the parasitic forms are included. In the "Guide", the insects with only larval stages in aquatic habitats were mentioned only briefly and no species lists were included. In this supplement this gap is largely filled by added notes and inclusion of species lists of all these groups except the Neuroptera, Lepidoptera, Tabanidae, Syrphidae and Stratiomyidae. The orders Neuroptera and Lepidoptera have relatively few members in freshwater habitats and the families Tabanidae, Syrphidae and Stratiomyidae have forms with larvae in aquatic habitats and also in moist places which are not true freshwater habitats. At this time, it is not possible to separate those forms living in freshwater habitats. Short diagnoses of six additional families are given, namely, the ixidae, Psychodidae, Tabanidae Stratiomyidae, Rhagionidae and Sciomyzidae. Keys are provided for the Odonata and Ephermeroptera larvae down to the family level. An attempt has been made to make the references more comprehensive. Works dealing specifically with the Ceylonese fauna are of course included, but in addition those which are of use in diagnosis of local genera and species have been cited.
    • A guide to the freshwater fauna of Ceylon. Supplement 3

      Fernando, C.H. (1969)
      This supplement to the “Guide to the freshwater fauna of Ceylon” by A. S. Mendis and C. H. Fernando. Bull Fish. Res. Stn. Ceylon 12, 160 pp. (1962) includes a number of additional records to the fauna and nomenclatural changes designed to bring the names of the Rotifera, and Hydracarina up to date. This latter involves a complete change in naming of Rotifera to keep in line with modern nomenclature synonymizing species where necessary. A major study on the water mites of India by Cook (1067) has necessitated considerable changes in the naming of Ceylonese species. Besides the Rotifera and Hydracarina the Ilemiptera-Heteroptera have received attention as regards the Corixidae and new generic and specific records from published and unpublished material has been included. A major difficulty in studying freshwater animals (for that matter any animals) is the lack of suitable illustrations of local forms. An attempt has been made to fill this gap for the Rotifera and Turbellaria, It is hoped that in future supplements other groups can be similarly dealt with.
    • A preliminary report on Chanos fry surveys carried out in the brackish water areas of Mannar, Puttalam and Negombo

      Ramanathan, S. (1969)
      This paper records the results of the Chanos fry surveys carried out in Mannar, Puttalam and Negombo lagoon areas since 1967, and gives a summary of the earlier surveys. The maximum amount of Chanos fry was obtained from Mannar area during April and May. All three areas have their main commercial fry season in April and May with a second commercially negligible season in October–November. The quantity of fry collected has been utilized to evaluate the potential fry production figures. Mannar 400,000,000 fry/annum. Puttalam 200,000,000 fry/annum. It would be extremely difficult to estimate the number of eggs laid, the larvae hatched and the fry available each year along the coastal areas of Ceylon. It is necessary to obtain biological, meteorological and oceanographical data so as to provide a basis for the prediction and estimation of fry populations in the coastal waters of Ceylon. The suggested ideal season for commercial catches of Chanos fry is April–May with operations to be carried out simultaneously all along the west coast.
    • A Preliminary study of the defensive spines of some Malayan freshwater fishes

      Fernando, C.H. (1964)
      The defensive spines of fifteen Malayan freshwater fishes have been studied morphologically. The classification of spines has been slightly modified from the previous work of Fernando and Fernando (1960). They are divided into simple, denticle-bearing and venom-carrying. The simple spines are further sub-divided into single and multiple and the denticle-bearing into Bagriid and Clariid types. The latter agree morphologically with the venom-carrying spines of previously studied forms and may be a degenerate condition. Simple spines occur singly in the Cyprinidae where they are found at the anterior end of the dorsal fin. A spine of similar structure occurs in the catfish Glyptothorax. In the families Anabantidae, Cichlidae and Mastacenbelidae simple spines occur as a series. Denticle-bearing spines occur in the catfishes (Order-Nematognathi). Those having denticles on one face occur in the Bagridae, Siluridae, Sisoridae, and Akysidae. They are referred to as Bagriid type. In the other type denticles occur on the anterior and posterior faces of the spine. They are referred to as Clariid type. None of the Malayan species studied had venom-carrying spines and they are unlikely to be found in the freshwater species. The functioning of the defensive mechanism whose morphological bases are spines is discussed and the relation between the size and habitat on the effectiveness of the spines is mentioned. The evolution of defensive spines is discussed briefly.
    • A preliminary study of two village tanks (reservoirs) in the Polonnaruwa area with biological notes on these reservoirs in Ceylon

      Fernando, C.H.; Ellepola, W.B. (1969)
      The present study was initiated in conjunction with a project to utilize some of these small tanks as fishponds by introducing desirable species like Tilapia mossambica Peters and harvesting them at the end of a single season which may vary from 4-8 months depending on the reservoir. Two reservoirs Timbirigaswewa and Dalukanawewa were chosen for this study. Both of these are in the Polonnaruwa area (Fig. 1). Timbirigaswewa (Fig 4) is as all rain fed tank of about 30 acres while Dalukanawewa (Fig. 2) is stream fed with an acreage of just over 100.
    • A preliminary study on the cuttlefish catches from the Wadge Bank trawler fishery

      Dayaratne, N.M.P.J. (1978)
      Although much work has been done on the evaluation of the Wadge Bank fishery data, no detailed study has been made in the past on the analysis of cuttlefish catches. In this paper an attempt has been made to analyse this data in order to gather a preliminary knowledge of seasonal and annual variation in the availability, distribution by depth and catches in relation to the time of the day.
    • A preliminary study on the keeping quality of locally produced marine and freshwater salted dried fish

      Goonewardene, I.S.R.; Etoh, S. (1980)
      Experiments were conducted on the storage life of salted dried fish from both freshwater and marine species. It was found that the storage life of salted dried products from the 2 freshwater species tested (Ompok bimaculatus and Labeo dussumieri) is much longer than that of the 2 marine species (Gonialosa manminna and Chorinemus lysan), i.e., 51 days.
    • A Preliminary survey of 21 Ceylon lakes. 1. Fisheries of two lakes, Parakrama Samudra and Minneriya Wewa

      Indrasena, H.H.A. (1965)
      Fourteen species of indigenous fish and three species of introduced fish commonly used for food are present in Parakrama Samudra and Minneriya Wewa. Commercial fishing is done throughout the year in these two lakes by gill nets, shore-seines ("Ma-del" nets) and cast nets. From records of fish landings maintained from 1957 it is seen that the production of fish at Parakrama Samudra has increased from 41 pounds per acre per annum in 1957 to 117 pounds per acre per annum in 1962 and at Minneriya Wewa from 11 pounds per acre per annum in 1957 to 118 pounds per acre per annum in 1962. Tilapia mossambica formed the chief constituent of the catch at both these lakes and it was due to this fish that the commercial fisheries at both these places were successful. It is recommended that fishing effort be further increased in both these lakes and records be kept to note any tendency towards over-exploitation.
    • A Preliminary survey of 21 Ceylon lakes. 2. Limnology and fish production potential

      Mendis, A.S. (1965)
      Some morphometric, physical and chemical conditions of 21 lakes in Ceylon are described. The values for the organic matter in the plankton and for the dry weight of bottom fauna in the lakes have been calculated. These values have been utilised to evaluate the potential fish production figures for the lakes. Fishing trials were made in each lake. Suggestions regarding mesh sizes and time of fishing are put forward.
    • A Preliminary survey of 21 Ceylon lakes. 3. Parasites and predators, food of fish, and marginal fauna

      Fernando, C.H. (1965)
      Three nematodes, two acanthocephalans and three cestodes were collected by dissecting 15 species of fish. Of these parasites only Hedruris sp. a larval nematode is responsible directly for the death of fish, since it is found in predatory species a reduction of these might prove of considerable consequence to fish, production. Bothriocephalus gowleonensis, a cestode probably introduced from China with Chinese carp, was recorded in an indigenous carp Puntius sarana. This parasite causes heavy mortality in grass carp in China and is a potential danger to local species. A single crustacean parasite was recorded. It is likely that they are widespread. No protozoa were recorded but there can be little doubt that they occur in local freshwater species and may be of considerable importance in fisheries. Several predators (insects, fish and other vertebrates) were recorded and are doubtless of considerable importance. However, the role of parasites and of predators (especially fishes) in relation to the productivity of fisheries can hardly be assessed at present and needs further study. A study of the fauna found at the shallow edges of 21 irrigation reservoirs showed an abundance of fauna in the low-country reservoirs whilst the up-country reservoirs had a poor fauna. The fauna showed insects, crustacea and mollusca in this order of abundance. The presence of insect and molluscs feeding fish in our fauna shows that these rich sources of food are being utilised.
    • A Review of the parasitic copepods of fish recorded from Ceylon with description of additional forms

      Kirtisinghe, P. (1964)
      The beginning of our knowledge of the copepods parasitic on fish from Ceylon is due to Bassett-Smith (1898 a) who, in a paper on "Further New Parasitic Copepods found on Fish in the Indo-Tropical Region", included seven species collected at Trincomalee and Colombo. Later in the same year, in a paper on "Some New or Rare Parasitic Copepods from the Indo-Tropical Region", he (Bassett-Smith, 1898 b) included three more species from Ceylon. Soon after, more of these parasites were obtained from Ceylon during Herdmann's investigation of the Pearl Banks. From this collection, one lot consisting of eleven species was described by Thompson and Scott (1903) and a second lot consisting of seven species was described by Wilson (1906). At that stage the number of species recorded from Ceylon made up to a total of twenty-eight and there the matter rested for another quarter of a century until, quite by chance, while collecting marine animals on a reef, Mr Kirtisinghe came across a newly dead half-beak with a learned parasite projecting from its body. Since then, in a number of occasional papers (Kirtisinghe, 1932-35, 1937, 1950, 1956, 1960) he has described thirty-eight more species of parasitic copepods from Ceylon. However, his collection included many more species which were put aside for later attention. In the present paper, while dealing with those forms in his collection which he has not recorded or described earlier, he has put together all the known forms of parasitic copepods of fish from Ceylon. A list of the host fishes with their respective parasitic copepods is also provided, types of new species, at present in the author's private collection, will be deposited in the Fisheries Department, Colombo, Ceylon.
    • A survey of process hygiene in the Sri Lankan prawn industry. 1. Hygiene status of raw materials and products

      Sumner, J.L.; Goonewardene, I.S.R.; Fonseka, T.S.G. (1980)
      A survey of processing hygiene in the Sri Lankan prawn industry has shown that the incoming raw material has extremely high bacterial loadings; about 50% of samples analysed had a total count in excess of 10,000,000/g. Although beheading reduces the count, ineffective temperature control during processing means that the final total count of raw, shell-on, P.U.D. and P.A.D. prawns, as well as cooked prawns, is in excess of 1,000,000/g. - the maximum level specified by many importing countries.
    • A survey of process hygiene in the Sri Lankan prawn industry. 2. The hygiene status of personnel

      Sumner, J.L.; Goonewardene, I.S.R.; Fonseka, T.S.G. (1980)
      Of 262 personnel tested, 137 (52%) were found to be positive for Staphylococcus aureus. Among individual companies the prevalence of S. aureus ranged from 92% (Company No. 1) to 22% (Company No. 2). Although five companies provided a sanitiser hand-dip, this was found to be ineffective for the control of S. aureus. Provision of hand-washing facilities, of protective clothing and of toilet facilities was found to be inadequate for an export food industry.
    • A survey of process hygiene in the Sri Lankan prawn industry. 3. Critical control points

      Sumner, J.L.; Goonewardene, I.S.R.; Fonseka, T.S.G. (1980)
      Of fifteen processing plants surveyed in Sri Lanka, only five were found to have a prawn process which was adequately controlled. Most common process faults were: inadequate chilling of prawns after a wash in 30°C, mains water, the use of large blocks of ice to cool prawns, and high ratios of prawns to ice. There was also ample scope for cross-contamination of the processed prawns.
    • Agar from Gracilaria lichenoides and Gracilaria confervoides from Ceylon

      Durairatnam, M.; Grero, J.; Wimalasiri, P. (1972)
      "Agar-agar" is a name derived from the jelly obtained from certain red algae in Malaya. In Sri Lanka agar is prepared from the red seaweeds Gracilaria confervoides and Gracilaria lichenoides. They are commonly known as Sri Lanka moss and the local names are "kandha parsi or sanchow parsi". The uses of agar are given together with details of the method of extraction of this substance from Gracilaria lichenoides and Gracilaria confervoides.