The distribution of penaeid prawns in Ceylon waters

Thirty one species of penaeid prawns have been discovered in Ceylon waters. A taxonomic study of these species was carried out and their distribution in relation to hypothetical oceanographical barriers was discussed (De Bruin 1965.) As penaeid prawns are of important commercial value, a study was made of their distribution and relative abundance in the estuaries and seas round the island. The results of this study are reported in this publication.

Taxonomic notes on a collection of flying fishes from Ceylon waters

The present study reports another seven species of flying fishes and brings the total for Ceylon to fifteen. Eleven of these fifteen species are represented in the author's collection. A key based on Breader (1938) and Parin (1960) and descriptive notes for these eleven species are given in this paper.

Results of a stratified random bottom trawl survey for scad and mackerel in Mozambican waters, from May to June 1984

The total abundance of small pelagic species in Mozambican waters was estimated to be 100 (plus or minus 45) thousand tonnes of which scad and mackerel constituted 57 (plus or minus 39) thousand tonnes. These abundance estimates must be considered as minimum estimates of biomass as the efficiency of the trawl was assumed to be equal to 1.0.

Results of a random stratified bottom trawl survey for scad and mackerel stocks in Mozambican waters: small pelagic fish December-January 1985

The results obtained during the third phase of Nauka are reported concerning the standing stock estimates, population length structure and gonad development of scad and mackerel stocks and the catch composition in Mozambican waters.

A review of the fisheries of the Uganda waters of Lake Albert East Africa, 1928-1965/66, with catch data mainly from 1953

An historical account is given of the development of the Lake Albert fisheries since Worthington's survey in 1928. It is noted that the development of the fisheries was related to, and dependent upon, improvements in the type of gear and canoes, an incFease in the number of canoes and outboard engines in use, improved marketing facilities and better road communications. Summarized data, collected mainly since 1954, has been analysed and tabulated to show annual exports to the Congo, total annual catches 'and annual catches of individual species. A change in the relative abundance of the various species in the annual catches is described. It is noted that this change was caused by a change-over from large to small mesh size gill-nets, and that it was associated with an increased demand within Uganda for the smaller species of fish, such as Aleste's baremose and Hydrocynus forskahlii. A brief description of fish processing and marketing in the Lake Albert region is given, which emphasizes the suitability of salt-cured fish to the social and physical environment of the area. Finally, a summary of a recent survey of the potential fish resources of the lake is given in the discussion, and estimates of the 1965 catch at the north and south ends of the lake are compared with the findings of the survey. This showed that there is little danger of overfishing the Alestes baremose stocks of the Wanseko area at the 1965 rate of exploitation of the species, and that the total catch for 1965 at the south end of the lake was well below the estimated annual sustainable yield from the area.

Demersal fishery resources of Sri Lanka and its present level of exploitation with special reference to off-shore and deep-sea waters

Following a brief review of development of demersal fishing off Sri Lanka, the author reviews the fishing grounds of the Wadge Bank, the Pedro Bank, and the Mannar Bank. He reviews the deepwater trawling fisheries particularly in relation to the 1972 survey conducted by the 'Optimist' and also small boat trawling in coastal waters. Lastly he considers handlining for groundfish, which is principally conducted by fishermen operating traditional craft.

Pelagic fishery resources of Sri Lanka and its present level of exploitation with special reference to off-shore and deep-sea waters

Pelagic resources around Sri Lanka may be categorized into three major groups: (1) the small pelagic varieties such as the sprats, halmessa, sardines (salaya, soodaya), and herrings (hurulla). (2) the medium size pelagic species such as the mackerel (kumbala and bolla), barracuda (jeela), seer Spanish mackerel (thora), frigate mackeral (alagoduwa), mackerel tuna (atawalla) and the skipjack (balaya). (3) the large size fishes such as yellow fin tuna (kelawalla), big eye tuna, marlins (koppora and gappara), sail fish (thalapath), sharks (mora) and rays (maduwa). Production levels of exploited resources are noted, and seasonal patterns and annual in their abundance are considered. On the basis of observations and estimations of the existing fisheries, and the results of experimental fishing, figures are presented of the potential yield of those species already exploited. The development of that potential depends on the development of modern techniques of pole and line fishing, application of tuna longline and shark longline, increasing the number of units of drift nets and the introduction of a bait fishery for the longline and pole line fishery. Some features upon which the successes of any venture to exploit such resources are noted, particularly those which relate to the nature of the fishing vessels used.

A report of the Fisheries Catch Assessment Survey in the Ugandan waters of Lake Victoria for the August 2006 survey

This report presents findings of the CAS conducted in the Ugandan waters of Lake Victoria in August 2006. The results of the previous five CASs conducted under the same programme in July, August, September, and November 2005, and March 2006 are included to show the emerging trends. The results of the preceding CASs, which were hitherto estimated using raising factors from the 2004 Frame survey data, are updated in this report using raising factors based on the 2006 Frame survey data. Through regular CASs, information is building up to show the new picture of fish production in the Ugandan waters of the lake which is based on field observations. Similar surveys are simultaneously conducted in the Kenyan and Tanzanian parts of the lake which provide the lake wide perspective of fisheries production.

Occurrence of whale sharks in coastal waters in the Indian Ocean: an interesting coincidence

Salinity, temperature and pressure are parameters which govern the oceanographic state of a marine water body and together they make up density of seawater. In this contribution we will focus our interest on one of these parameters, the salinity: accuracy in relation to different purposes as well as observation technique and instrumentation. We will also discuss the definition of salinity. For example most of the Indian Ocean waters are within the salinity range from 34.60-34.80, which emphasize the importance of careful observations and clear definitions of salinity, in such a way that it is possible to define water masses and predict their movements. In coastal waters the salinity usually features much larger variation in time and space and thus less accuracy is sometimes needed. Salinity has been measured and defined in several ways over the past century. While early measurements were based on the amount of salt in a sea water sample, today the salinity of seawater is most often determined from its conductivity. As conductivity is a function of salinity and temperature, determination involves also measurement of the density of seawater is now more precisely estimated and thus the temperature. As a result of this method the Practical Salinity Scale (PSS) was developed. The best determination of salinity from conductivity and the temperature measurements gives salinity with resolution of 0.001 psu, while the accuracy of titration method was about ± 0.02‰. Because of that, even calculation of movements in the ocean is also improved.

Status of the gill net fishery for the small pelagic fish species in western, south-western and southern coastal waters of Sri Lanka during 1995-1997

Small pelagic fish species are mainly caught by gill nets operated by fibre reinforced plastic boats fitted with 8-25hp out board engines, traditional crafts fitted with 8-1hp out board engines and non mechanised traditional crafts. Around 28 to 55% of the small pelagic catch in the study area consisted of trenched sardine Amblygaster sirm during 1995-1997 period. Another 26-36% of the catch composed of other Sardinella species such as Sardinella gibbosa, S. albella, S. sindensis and S. longiceps. Engraulids such as Encrasicholina heteroloba, Stolephorus insularis and Stolephorus indicus and Thryssa spp formed around 3-5% of the catch. The major component of this fishery consisted of Clupeids and Engrauhds and over 65 species ranged between smaller Engraulids to incidental rock fish, sail fish, seer fish, sharks, skates and rays. Around 1.4 to 1.9% of the catch consisted of Chirocentrus dorab, Sphyraenaspp, Scomberomorus spp, Lepturcanthus sp and Megalaspis cordyla. Around 1-11% of the catch consisted of incidentally catches of sharks, rays, skates and sail fish. Another 1.6 to 6% of the catch consisted of Selar crumenophthalamus and Rastrelliger kanagurta. The best fishing season appeared to be from June to October in the west coast and August to December in the south coast. The major components of Amblygaster sirm, Sardinella albella and Sardinella gibbosa were caught within the size ranges of 10.0-22.5 cm, 11.0-13.0 cm and 11.0-15.0 cm respectively. However, smaller sized fish of above species of sizes between 6.9 cm to 9.7 cm total length were incidentally caught in the gill nets operated for small Engraulids with a stretched mesh size of 1.6cm. The overall catch rate for the major fish landing centre at Negombo indicated an increase from 38.5 kg/boat trip during 1984-1990 period to 49.5 kg/boat trip during 1995-1997 period. The catch rate for the dominant species Amblygaster sirm has decreased from 28.17 kg/boat trip during 1983-1990 period to 17.47 kg/boat trip during 1995-1997 period at Negombo. The paper also discusses the changing overall catch rates, change in species abundance and possible management consequences that should be considered.

A report of the fisheries catch assessment surveys in the Ugandan waters of Lake Victoria for November 2005

The fisheries of Lake Victoria have undergone many changes in the recent past which have been characterized by shifts in abundance of different fish Species and changes in fishing effort. Monitoring of the population dynamics as well as the magnitude, distribution and trends of fishing effort and fish Catches is probably more necessary now than ever before for sound management of the fisheries of the lake. This will enable the formulation of appropriate fisheries policies and legislation to ensure that the fisheries are sustainable. One of the avenues to collect information to support the above process is through conducting regular Catch Assessment Surveys (CASs). The EU funded Implementation of a Fisheries Management Plan (IFMP) project for Lake Victoria through the Lake Victoria Fisheries Organization (LVFO) is supporting the implementation of regionally harmonized CASs in Lake Victoria. The CASs under IFMP are following a statistically design laid down in Standard Operating Procedures (SOPs) agreed around the whole lake. In the Ugandan part of the lake, the CASs are carried out at 54 fish landing sites selected in the eleven districts sharing the lake. They are jointly conducted by the Fisheries Resources Research Institute (FIRRI), Jinja; the Department of Fisheries Resources (DFR), Entebbe; and the Districts of Busia, Bugiri, Mayuge, Jinja, Mukono, Wakiso, Kampala, Mpigi, Masaka, Kalangala and Rakai. The CAS enumerators are recruited from the fishing communities and work under direct supervision of sub county Fisheries Officers. It is planned to involve the recently formed Beach Management Units (BMUs) in fisheries data collection when modalities for their roles have been streamlined.

A report of the Fisheries Catch Assessment Survey in the Ugandan waters of Lake Victoria for the August 2007 survey

The monitoring of fish stocks as well as the magnitude, distribution and trends of fishing effort and fish catches is required for sound fisheries resources management. Conducting regular Catch Assessment Surveys (CASs) in Lake Victoria is one of the ways through which the partner states sharing the lake are generating information to contribute to the above process. The EU funded Implementation of a Fisheries Management Plan (IFMP) project for Lake Victoria through the Lake Victoria Fisheries Organisation (LVFO) is supporting the implementation of regionally harmonised CASs in Lake Victoria . The CASs under IFMP are following a statistical design laid down in Standard Operating Procedures (SOPs) agreed by the three partner states of the East African Community sharing the lake. In the Ugandan part of the lake, the CASs are carried out at 54 fish landing sites selected in the eleven riparian districts sharing the lake. The National Fisheries Resources Research Institute (NAFIRRI), Jinja; the Department of Fisheries Resources (DFR), Entebbe; and the Districts of Busia, Bugiri, Mayuge, Jinja, Mukono, Wakiso, Kampala, Mpigi, Masaka, Kalangala and Rakai jointly conduct the surveys. The CAS enumerators are recruited from the fishing communities and work under direct supervision of subcounty Fisheries Officers. NaFIRRI seeks to continue strengthening the engagement of the Beach Management Units (BMUs) and other fisheries Co-management Institutions in fisheries data collection .

Morphometry and length-weight relationship of Coilia dussumieri, Valenciennes, 1848 from Mumbai waters

Coilia dussumieri Valenciennes, 1848 a component of 'dol' net fishery forms an important pelagic resource along northwest coast of India. The present communication deals with morphometry and length-weight relationship of this species along Mumbai coast. Morphometric study showed a positive correlation among the compared characters. The length-weight relationship for the species from Mumbai coast was found to be W=0.017L super(2.4223).

Reproductive biology of Otolithes cuvieri (Trewavas, 1974) from Mumbai waters

The reproductive biology of Otolithes cuvieri (Trewavas, 1974) is reported in the present communication. The size at first maturity for the females was estimated to be 275 mm. The spawning activity was observed throughout the year with two peaks occurring in April and June. Two prominent peaks of gonadosomatic index (April and June) also support the view of two major spawning. Relative fecundity ranged from 71,574 to 79,680 eggs per 100g of body weight. Relationship of fecundity with fish length, fish weight and ovary weight of the species has been established as F = -132971 + 1447.441 x L, F = 124195 + 468.798 x W and F = 250517.5 + 3369.029 x OW, respectively. Study of sex ratio by random sampling of the catches indicated the dominance of females in commercial catches of Mumbai coast.

Population dynamics of two jewfishes Jhonius argentatus and Johnieops vogleri) in the coastal waters of Bay of Bengal, Bangladesh

Population parameters of Jhonius argentatus and Johnieops vogleri in coastal waters of Bay of Bengal, Bangladesh were estimated by using FiSAT programme. The von Bertalanffy growth parameters, extreme length (cm) and growth constant K (year ·1) were found to be 46.50 and 0.59 for J. argentatus, and 33.50 and 0.85 for J.vogleri The Loc(cm) and Z/K estimates provided by Wetherall plot were 46.694 and 1.791 for J. argentatus, and 31.25 and 2.623 for J. vogleri. The annual rate of natural (M) and fishing mortality (F) were estimated as 1.12 and 0.78 for J. argentatus, and 1.56 and 1.28 for J. vogleri. Rate of exploitation (E) was estimated as 0.41 for J. argentatus and 0.45 for J. vogleri. About 80.04% of J. argentatus were found to be recruited during peak pulses (April-May) and 19.96% during lean pulses (October-November) and 85.75% J. vogleri during peak pulses (May-July) and 14.25% during lean pulses (September-October). The growth performance index(') was 3.11 for J. argentatus and 1.93 for J. vogleri. The total length and body weight relationship was found to be W = 0.0403 TL25723 for J. argentatus and W = 0.0907 TV3482 for J. vogleri.