Influence of climate on environmental factors associated with long-term changes in chlorophyll production for the Sacramento-San Joaquin delta and Suisun Bay, California

Long-term changes in chlorophyll production were predicted from environmental variables for the Sacramento and San Joaquin rivers and Suisun Bay using Box-Jenkins transfer function models. Data used for the analyses were collected semimonthly or monthly between 1971 and 1987. Transfer function models developed to describe changes in chlorophyll production over time as a function of environmental variables were characterized by lagged responses and described between 39 and 51 percent of the data variation. Significant correlations between environmental variables and the California climate index (CA SLP) were used to develop a conceptual model of the link between regional climate and estuarine production.

Seasonal and spatial distribution of Chlorophyll a in the north Arabian Sea bordering Pakistan

The average integrated chlorophyll a values for a 30-m deep surface layer in the north Arabian Sea bordering Pakistan ranged from negligible amounts to as high as 0.53μg chl. a 1ˉ¹(15.9mg mˉ²) during the period January 20, 1977 to June 4, 1977. The values, in general, decreased offshore except for the westernmost part of the Makran shelf, where unexpectedly high values were recorded over deep water. Seasonal distribution showed very high values in January (northeast monsoon season) which, with a few exceptions, gradually decreased to very low values in May, and then increased in June. The January peak may be related to winter cooling of surface waters resulting in convection and the June peak to the onset of southwest monsoon season in May. Coastal water shallower than 30m showed no seasonality and were often sites of intense phytoplankton blooms.

Comparative account of growth rate of body parts with total length in adult Puntius sarana (Ham.)

The present study on growth rate of different body parts in relation to total length, in the male and female Puntius sarana (Ham.) did not show any significant heterogeneity except in snout length (p.01). The growth rate of snout length was found to be higher in females (b=0.0377) than in males (b=0.0266). Since the growth rate of most of the body parts was found to be homogeneous in both the sexes, the common regression co-efficient "b" was calculated on pooled data to represent the growth rate of different body parts against total length, the linearity of regression lines indicated isometric growth.

Comparative account of growth rate of body parts with total length in Rita pavimentata (Gunther)

The paper deals with sex-wise growth rate of different body parts in relation to total length in Rita paviinentata (Gunther). Growth rates calculated on pooled data by using the common regression coefficient 'b' reveals isometric and homogeneous nature in sexes.

Studies on fecundity of Puntius sarana (Ham.) in relation to total length, total weight and ovary weight

A total of 43 mature female of Puntius sarana (Ham.) ranging from 204 mm to 320 mm in length and 102 to 482 g in weight were used for present studies. The relationship between fecundity with respect to total length (TL), total weight (TW) and ovary weight (OW) was found to be linear. The coefficient of co-relation 'r' of the above relationships was found to be 0.5947, 0.5761 and 0.9837 respectively. All these values are highly significant (P=0.01) indicating a close relationship between these parameters. However, as indicated by value of 'r' (0.9837), the fecundity is more closely related to ovary weight and hence the ovary weight may be a better index of fecundity than the total length or weight.

Studies on fecundity of Rita pavimentata (Gunther) in relation to total length, total weight and ovary weight

A total of thirty eight ripe ovaries from the specimens of Rita pavimentata, measuring 230 to 355 mm in total length (TL) and 250 to 750 g in total weight (TW), were selected to study the fecundity. The relationship between fecundity 'and total length (TL), total weight (TW) and ovary weight (OW) was found to be linear. The coefficient of co-relation 'r' of the above relationship was found to be 0.92, 0.94 and 0.96 respectively. All these values are highly significant (P=0.01) indicating a close relationship between compared parameters. However, as indicated by value of 'r' (0.96), the fecundity is more closely related to ovary weight and hence the ovary weight may be a better index of fecundity than the total body length or weight.

Effects of iso-nitrogenous fertilizers as nutrient sources on carp polyculture in Bangladesh

A 120-day long experiment was conducted to find out the effects of urea plus triple super phosphate (UT), cow manure (CM) and poultry manure (PM) having iso-nil:rogen content on pond productivity and fish yield. Three fertilizer treatments, with three replicates each, were randomly assigned into nine earthen ponds of 100 m2 each. The stocking fish were rohu (Labeo ruhita), catla ( Catla catla) and mrigal ( Cirrhinus mrigala) in each treatment pond at the rate of 10000/ha with the ratio of 1:1:1. All ponds were fertilized fortnightly at the rate of 125 kg/ha urea plus 100 kg TSP/ha, 7000 kg/ha cow manure and 3500 kg/ha poultry manure for the treatment of UT, CM and PM, respectively, having an iso-nitrogen content of 56 kg in each. Though the physicochemical water quality parameters were more or less similar in all treatment ponds, the chlorophyll-a content and abundance of total plankton were significantly higher (P < 0.05) in the ponds receiving the treatment PM. Final growth as well as per unit production of fish was significantly higher (p

Relationship between total length and mouth gap of some commercially important carp fry

The estimated regression equation for total length and mouth gape computed were Log TL = Log 0.23 + 0.663 log MG (vertically) (r = 0.960) and Log TL = Log 0.08 + 0.686 log MG (horizontally) (r = 0.949). In case of rohu average total length from 11350 mm to 23775 mm and mouth gape 805 um to 1225 um (vertically) and 700 um to 1110 um (horizontally) between the first day of mouth opening up to 15 days. The regression equation for total length and mouth gap were Log TL = Log 0.20 + 0.660 log MG (vertically) (r = 0.935) and Log TL = Log 0.02 + 0698 log MG (horizontally) ( r = 0.907). In case of silver carp average total length from 12800 ,urn to 33555 um and mouth gape 690 um to 1210 um (vertically) and 615 um to 1115 um (horizontally) between the first day of mouth opening up to 15 days. The regression equation for total length and mouth gape were Log TL = Log 0.36 + 0.596 log MG (vertically) (r = 0.936) and Log TL = Log 0.26 + 0.607 log MG (horizontally) (r = 0.891). The relationship between total length and mouth gape (vertically and horizontally) of the studied fry were found to be linear and highly significant.

Performance of Amblypharyngodon mola with Barbodes gonionotus, Cyprinus carpio and Macrobrachium rosenbergii in rice-fish culture system

An experiment was conducted to assess the performance of mola (Amblyphmyngodon mola) in rice fish culture system with freshwater prawn Macrobrachium rosenbergii), Thai silver barb (Bm·bades ganianotus) and common carp (Cyprinus cmpia) for a period of 4 months at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, Bangladesh. Four treatments viz., treatment-I (T1) with A. mala and M. rosenbergii; treatmen t-II (T2) with A. mala, M. rosenbergii and B. gonianatus ; treatmentIII (T3) with A. mala, 1Vf. rosenbergii and C. cmpia, and treatment- IV (T4) as control (without fish) were used in triplicate. All treatments were equally fertilized with urea (200 kg/ha), TSP (150 kg/ha) and MP (75 kg/ha). The mean values of water quality parameters viz., temperature, dissolved oxygen, pH, nitrate-nitrogen showed a very small variations among different treatments, but phosphate-phosphorus and chlorophyll-a were relatively higher in T4 without fish (i.e., control). The fish production of 480.5 kg/ha in T3 was significantly higher than that of 355.6 kg/ha T2 and 223.8 kg/ha in T 1• The values of soil organic matter, total-nitrogen, phosphorus and potassium at harvest were significantly (P<0.05) higher in the treatments with fish than without fish, but pH did not show any significant differences. The yield of rice grain and straw was also obtained significantly (P<0.05) higher in the treatments with fish. The increase in grain was higher over the control by 11.81%, 9.41% and 14.76% and that in straw was by 9.83%, 4.77% and 13.29% in Tl> T2, and T3 respectively.

Growth performance of Chlorella ellipsoidea as biomicrocapsule using supernatant of digested sugar mill waste effluent

Biomicrocapsules mean microscopic living organisms which carry important nutrients, very essential for the growth and development of aquatic organisms as well as other animals. Among these biomicrocapsules, Chlorella ellipsoidea, an important green microalga (Chlorophyceae) which contains 40-45% crude protein, 12-16% crude lipid, 14-15% minerals, colour pigments, vitamins and carotene. The microalga, C. ellipsoidea was cultured in four different dilutions of supernatant of digested sugar mill effluent (DSME) i.e. 25, 50, 75 and 100% DSME and Bold basal medium (BBM) as control in laboratory condition. Maximum cell growth and chlorophyll a content of C. ellipsoidea were obtained on l0th day of culture in supernatant of 50% diluted DSME followed by those of this biomicrocapsule grown in BBM, and 75, 25 and 100% DSME at stationary phase. Cell number had highly (p<0.01) direct correlation with chlorophyll a (r = 0.889) of C. ellipsoidea, and optical density (r = 0.926) of media. Chlorophyll a was also highly (p<0.01) and directly correlated with optical density (r= 0.877) of media. The specific growth rates (µ/day) of cell and chlorophyll a of C. ellipsoidea grown in supernatant of 50% DSME were significantly (p<0.01) varied from those of C. ellipsoidea cultured in BBM followed by other DSME. Total biomass of C. ellipsoidea cultured in supernatant of 50% DSME was found significantly (p<0.01) higher than that of this microalga cultured in BBM, and supernatant of 25, 75 and 100% DSME. Similar trend was also observed in the case of optical density. The physico-chemical properties of media were varied with the growth of cell of this microalga. It was recorded that cell number, chlorophyll a of biomicrocapsule, and optical density of media were highly (p<0.01) and directly correlated with pH, hardness and alkalinity, and inversely correlated with nitrate-N. Crude protein and crude lipid of C. ellipsoidea grown in supernatant of 50% DSME were significantly (p<0.01) higher than those of C. ellipsoidea cultured in other DSME and BBM. Due to best growth performance exhibited by this microalga grown in supernatant of 50% DSME, it may be used to grow in supernatant of 50% DSME to get more essential nutrients than that cultured in supernatant of other DSME media.

Effects of iso-nitrogenous and iso-phosphorus fertilizers as nutrient sources on carp polyculture in Bangladesh

A 120 day long experiment was conducted to find out the effects of cow manure with urea and triple super phosphate (CUT), poultry manure with urea and triple super phosphate (PUT) and cow manure with poultry manure (CP) having similar quantities of nitrogen and phosphorus on pond productivity and fish yield. The stocking fish were rohu (Labeo rohita), catla ( Catla catla) and mrigal ( Cirrhinus mrigala) in each treatment pond at the rate of 10000/ha. All ponds were fertilized fortnightly at the rate of 4000 kg/ha cow manure with 62 kg/ha urea and 65 kg/ha TSP, 2700 kg/ha poultry manure with 62 kg/ha urea and 16 kg/ha TSP, and 4000kg/ha cow manure with 2700 kg/ha poultry manure for the treatment CUT, PUT and CP respectively. Each treatment contained an iso-nitrogen and iso-phosphorus of 56 kg and 46 kg respectively. Though the physico-chemical parameters were more or less similar in all ponds, the chlorophyll-a content and abundance of total plankton were significantly higher (P< 0.05) in the ponds receiving the fertilizer treatment of PUT than those of other treatments. Final growth as well as per unit production of fish of treatment PUT (1773 kg/ha) was significantly higher (P< 0.05) than that of treatment CP (1528 kg/ha) followed by that of treatment CUT (1336 kg/ha). The over all results showed that poultry manure with urea and triple super phosphate proved to be superior to cow manure with urea and triple super phosphate, and poultry manure with cow manure, even when nitrogen and phosphorus content was similar, in carp polyculture system under prevailing conditions.

Size frequency distribution and carapace length-total length relationship of Acetes chinensis in the Kutubdia channel of Bangladesh coast

The seasonal mean size distribution of A. chinensis were estimated as 29.229mm ±4.77, 25.125mm ±2.55, 25.165mm ±2.29 and 32.44mm ±3.63 for annual, monsoon, postmonsoon and pre-monsoon period, respectively. Seasonal mean carapace length distribution were estimated as 9.37mm ±1.457, 8.063mm ±0.63,8.258mm ±0.59 and 10.37mm ±l.ll3 for annual, monsoon, post-monsoon and the pre-monsoon season. The carapace length and total length relationships was found to be TL= - 1.39±3.23 CL. Linear relation was found in arithmetic and as well as logarithmic scale.

HACCP based management system for improving quality of freshwater giant prawn, Macrobrachium rosenbergii

The study was conducted on the present status of HACCP based quality management system of golda, Macrobrachium rosenbergii farms in Fulpur region of Mymensingh. Information was collected on general condition of farms, culture systems and post-harvest quality management. In almost all farms, there is no or inadequate infrastructure facilities such as, road access, electric supply, telecommunications, ice, feed storage facility, vehicle for golda transportation, washing and toilet facilities. The problems associated with sanitation and hygiene was: widespread use of cow dung, poultry manure and construction of open toilet within the vicinity of prawn culture pond. Different grades of commercially available and locally prepared feeds were used for golda culture in the pond. Golda post-larvae (PL) of 40-50 days old were stocked with carp species. The price of golda PL ranged from Tk. 1.00 to Tk. 1.25/piece. The pond size varied from 50 decimal (0.2 ha) to 2.5 acre (1.0 ha) with an average depth of 2-2.5 m. The culture period of golda varied from April-May to November-December and survival rate ranged between 75 and 80%. Production of golda varied from 250-500 kg/acre (625-1,250 kg/ha). Harvested golda were transported to city market within 4 h. Two size grading were generally followed during pricing, e.g. Tk. 500 to 550/kg for >100 g size and Tk. 300/kg for <100 g size. The cost-benefit ratio was found to remain around 1:1.25 depending on availability of PL. Water quality parameters such as, water temperature, pH, dissolved oxygen, total alkalinity and chlorophyll a in five golda farms in Fulpur region were monitored. Water temperature ranged from 29°C to 33°C, dissolved oxygen from 2.28 to 4.13 mg/l, pH between 6.65 and 7.94, alkalinity from 44 to 70 mg/l and chlorophyll a concentration from 61.88 to 102.34 µg/l in the five investigated ponds. The Aerobic Plate Count (APC) of the water sample was within the range of 2.0x10^6 - 2.96x10^7 CFU/ml and of soil samples within the range of 6.9x10^6 - 7.73x10^6 CFU/g. Streptococcus sp., Bacillus sp., Escherichia coli, Staphylococcus sp., Pseudomonas sp. and Salmonella sp. were isolated from pond water and sediment. Different feed samples used for golda was analyzed for proximate composition. Moisture content ranged around 14.14-21.22%, crude protein 20.55-44.1%, lipid 4.67-12.54% and ash 9.7-27.69%. The TVB-N values and peroxide values of feeds used as starter, grower and fish meal were found within the acceptable ranges and samples were free from pathogenic organisms. A training was organized for the golda farmers on HACCP, water quality and post-harvest quality management of prawn.

Seasonal variations in the total cholesterol content of the liver of cat fish Heteropnuestes fossilis (Bloch)

Variations in the total liver cholesterol content of Heteropnuestes fossilis followed well defined seasonal cycle. A decline was recorded during the period when the gonads were passing through the peak ripe stage. The highest value of the cholesterol was however attained before this phase of gonad maturation. Concentration pattern of liver cholesterol seemed related to variations in the cholesterol metabolism of the fish, necessitated, besides other factors, by the demand for sex hormones. A possibility of the influence of feeding intensity on liver cholesterol content has also been indicated.