Comparison of physicochemical properties of muscle proteins in cultured and wild prawns (Penaeus (Fenneropenaeus) orientalis Kishinouye, 1918)

Protein physicochemical properties in cultured and wild prawns (Penaeus (F.) orientalis Kishinouye, 1918) were studied and compared. Protein fractions were separated into water-soluble, salt-soluble, alkali-soluble, and stroma. The results showed that salt- and alkali-soluble proteins were slightly higher in wild prawns and water-soluble proteins were higher in cultured prawns. There were only slight differences in Ca2+-ATPase, MG2+-ATPase, and ATP sensitivities. The textural values of wild prawns were significantly higher than the cultured ones.

Acute toxicity of four heavy metals to Sphaeroma walkeri and Ciroiana bovina (Crustacea:Isopoda)

The median lethal concentrations (LC50) of two Isopoda species exposed to each tested metal (Cu. Co, Cd and Zn) in static tests for different exposure periods are quite variable depending on the tested metal The LC50 values for Sphaeroma walkeri after 24 hours exposure to Cu and Co were estimated graphically to be 11.20 and 7.00 mg/1 respectively. The correspoding values for Cirolana bovina exposed to Cu, Co, Cd and Zn were 3.60, 11.0, 3.80 and 4.80 mg/1 respectively. For 2 days the LC50 of S. walkeri exposed to Cd was 5.60 mg/l, but it was 10.10 mg/l for 3 days exposure to Zn. After prolonged exposure the LC50 values decreased proportionally with the exposure duration of the test the percentages of surviving animals demonstrated a progressive decrease with increasing concentratins as a main factor from the analysis of variance (ANOV A). The sensitivity of adult S. walkeri exposed to the four heavy metals for different exposure times ranked: Cd>Co>Zn>Cu. Cirolana bovina appeared to be more sensitive to Cu. Cd and Zn than to Co. Species in order of increasing sensitivity is C. bovina more than S. walker.

Distribution of mercury in a tropical estuary (India) situated near a chloro-alkali plant

The distribution of mercury in water, sediment and some biological samples of the Rushikulya estuary, east coast of India were assessed during Jan-Dec. 1989. Both the dissolved plus acid leachable mercury contents in water and the sediment mercury discerned conspicuous spatial and seasonal fluctuations. Adsorption on to the suspended particulates was found to be the most likely mechanism for removal of mercury from the water column. Exchange of mercury from sediments to water was observed at high salinities (20-30x10-3). The residual mercury contents in the biological samples revealed that bio-accumulation by bottom-dwelling organisms are higher than the pelagic components.

A study on performances of intensification in the farming system of a shrimp farm at Cox's Bazar, Bangladesh

This study examines the harvest and mean production in relation to the stocking of P. monodon fry during the period between March 1992 and October 1994, at the farm owned by M/s Monugung Sea Food Ltd., Cox's Bazar. The analysis shows that production figures were initially up to expectation, but after harvesting 4 crops within 16 months, production sharply decreased. The unexpected high mortality of the growing stock was due to outbreak of an uncontrollabe disease (Vibriosis). Significantly higher variations in production, survival and growth were also noted among the different treatments.

Larval development of Micippa platipes Ruppell, 1930, reared under laboratory conditions (Crustacea, Decapoda, Majidae)

The ovigerous female of Micippa platipes Ruppell, 1830, captured from Buleji (Karachi, Pakistan) on February 7, 1993 and was kept under the laboratory conditions. On February 27, 1993 larvae were hatched in prezoeal stage. The presoeal stage of M. platipes passed through two zoeal stages within three to five days at room temperature (17-20C). The larvae are described, illustrated and compared with the larval account of Micippa thalia (Herbst, 1803) given by Kurata, 1969.

Phycochemical studies on sterols from three brown seaweeds of northern Arabian Sea

Three brown algae i.e. Dictyota hauckiana Nizamuddin, Levringia boergesenii Kylin and Spatoglossum variabile Figari et De Notaris, collected from the coastal areas of Karachi, have been investigated for their sterol composition. Four sterols with cholesta skeleton including a new one, 17α-hydroxy-24β-vinyl cholesterol have been isolated from them. Their structures were elucidated with the help of spectroscopic analysis. The new sterol has been named as hauckiosterol after its first source of isolation.

Description of stomatopod larvae from the Arabian Sea

The Northern Arabian Sea Ecological and Environmental Research (NASEER) Programme cruise I, January, 1992 and other collections from Manora Channel (Karachi) were examined. Six stages i.e. IV, VII, VIII, IX, X and XI of stomatopod larvae are recognized. Day samples talen in 1994 (January to December) from Manora Channel revealed the presence of only three specimens of stage IV. They all belong to the family Squillidae. Each stage is measured, described and illustrated. None of the stages could be correlated to their adults.

Determination of length-weight relationship of squid (Loligo duvauceli) found along Pakistan coast

Common squid (Loligo duvauceli) is caught as by-catch of shrimp trawlers in shallow coastal. waters off Pakistan. Size frequency data of squid for sexes combined collected from Karachi Fish Harbour were analyzed. The length-weight relationship of the form W = a.L b was determined and to mean length of squid sample measured compared with mean length derived from inverse equation was tested for any significant differences, none were observed and it was inferred that the equation W = 0.243xL 2.2424 describe the relationship.

Determination of length-weight relationship in Sepia pharaonis and test for sex specific variation

The parameters a and b of the length-weight relationship of Sepia pharaonis of the form of W=a.L was determined. Sex separated size fequency data collected from Karachi fish Harbour was analysed the length-weight equations, separable by male, female and sex combined. The apparent difference in paired values of exponents b1, b2 for any combination i.e. male versus female and male, female versus sex combined was tested for their significant difference. No significant difference was observed for any combination, this indicated no sex specific variation in length-weigh relationship of Sepia pharaonis.

An illustrated key to Malacostraca (Crustacea) of the Northern Arabian Sea part-V: Isopoda

The northern Arabian Sea Isopod fauna is keyed out, excluding the gulfs fauna. Some terrestrial species are also included. Previous accounts and recent collections from Pakistan mainly at Karachi have turned up 7 suborders, 18 families, 76 genera and 12 1 species. There 5 are new records from Pakistan. For each species, there is an illustration and information of its reporter from the area and on its host, if parastic. The source of illustration is also given.

Concentration and distribution of heavy metals (lead, cadmium, chromium, copper, nickel, zinc) in Karachi shore and offshore sediments

A study to measure the heavy metal pollution level in the sediment of coastal and offshore area indicates that high concentration of heavy metals were found around Manora channel and eastern coast of Karachi. In comparison with coastal areas, relatively low concentration of heavy metals was recorded in the offshore area. The result shows that sewage and industrial wastes are the main source of heavy metal pollution in the coastal area. The concentration of heavy metals in the sediments is as follows: Chromium 10.4-33.69, nickel 13.3-47.6, lead 10.0-39.04, cadmium 0.08-0.21, zinc 7.4-73.2 and copper 9.44-18.56 mg/kg. In the offshore areas strong correlation was observed between copper and organic carbon, and calcium carbonate and cadmium. In the shore area such correlation has been recorded among nickel, chromium, zinc, and chromium and copper. The Karachi. coast is viewed as moderately polluted when compared to other continental coastal areas.

Polychaetous annelids (order Sabellida) from the Karachi coast, Pakistan

Fifteen species of polychaete worms, belonging to order Sabellida, are described from the Karachi coast. Of these 10 are new records for Pakistan: Hydroides albiceps (Grube, 1870), H. exaltatus (Marenzellar, 1885), Protula sp. Spirobranchus tetraceros (Schmarda, 1861), Vermiliopsis infundibulum glandigera group, Demonax sp. and Bispira cf tricyclia (Schmarda, 1861).

Ecological imbalances in the coastal areas of Pakistan and Karachi Harbour

The marine environment of Pakistan has been described in the context of three main regions : the Indus delta and its creek system, the Karachi coastal region, and the Balochistan coast. The creeks, contrary to concerns, do receive adequate discharges of freshwater. On site observations indicate that freshwater continues flowing into them during the lean water periods and dilutes the seawater there. A major factor for the loss of mangrove forests as well as ecological disturbances in the Indus delta is loss of the silt load resulting in erosion of its mudflats. The ecological disturbance has been aggravated by allowing camels to browse the mangroves. The tree branches and trunks, having been denuded of leaves are felled for firewood. Evidence is presented to show that while indiscriminate removal of its mangrove trees is responsible for the loss of large tracts of mangrove forests, overharvesting of fisheries resources has depleted the river of some valuable fishes that were available from the delta area. Municipal and industrial effluents discharged into the Lyari and Malir rivers and responsible for land-based pollution at the Karachi coast and the harbour. The following are the three major areas receiving land-based pollution and whose environmental conditions have been examined in detail: (l) the Manora channel, located on the estuary of the Lyari river and serving as the main harbour, has vast areas forming its western and eastern backwaters characterized by mud flats and mangroves. The discharge of industrial wastewater from the S.I.T.E. and municipal effluents from the northern and central districts into the Lyari has turned this river into an open drain. This, in turn, has caused a negative impact on the environment of the port, fish harbour, and the adjacent beaches. (2) The Gizri creek receives industrial and municipal effluents from the Malir river as well as from several industries and power stations. The highly degraded discharges from the Malir have negatively impacted the environment in this creek. (3) The coastline between the Manora channel and Gizri creek where the untreated municipal effluents are discharged by the southern districts of Karachi, is responsible for the degraded environment of the Chinna creek, and also of the beaches and the harbour. The Balochistan coast is relatively safe from land-based pollution, mainly because of the lack of industrial, urban or agricultural activity, except the Hingol river system where some agricultural activities have been initiated.