Comparative efficiency of trawls made of nylon, polyethylene monofilament and tape twines

Results of comparative fishing operations conducted with three nets of identical design made of nylon, twisted polyethylene monofilament and high density polyethylene (HDPE) tape twines are presented in this communication. Since the tape net recorded the highest prawn and fish catch, monofilament and nylon following in order, it can be recommended to the fishing industry as one of the cheapest and effective fishing materials evolved for trawl fabrication.

Comparative evaluation of fish protein concentrate and functional fish protein concentrate from cat fish

Fish protein concentrate and functional fish protein concentrate samples were prepared from eviscerated meat of cat fish (Tachysurus jella Day). Functional fish protein concentrate is found to be lighter, less gritty and rehydrates more rapidly than fish protein concentrate. Functional FPC is seen to have higher PER and biscuits containing it at levels of 5 and 7 percent are less hard compared to FPC.

Double-rig shrimp trawling, its rigging, comparative efficiency and economics

A radical and revolutionary change from the hitherto employed shrimp trawling is reported for better productivity and economy in deep sea trawling with medium and large vessels. Studies carried out off Veraval with a 13.7 m. four seam shrimp trawl as conventional single-rig and two 6.8 m four seam shrimp trawls as double-rig from a 15.2 m fishing vessel showed an increase of 98% shrimp catch by double-rig over single-rig at 86.3 % of the power utilised by the latter. It has also been worked out, theoretically, how better this available power can be utilised for further improvement of catch. An increase of 15% head rope length in case of double-rig over the optimum single-rig gear of any vessel is recommended.

Comparative study of the nutrient content of fish and shell fish

The amino acid, mineral and proximate composition of mullet (Mugil oeur), mackerel (Rastrelliger kanagurta), crab (Scylla serrata) and prawn (Penaeus indicus) are reported. The data are used for comparing the nutritional quality of the fish and shell fish. Further, the amino acid composition is screened for their adequacy to meet the FAO/WHO recommended pattern of essential amino acids.

On the comparative efficiency of "V" shaped and rectangular flat otter boards for trawling off Veraval, north west coast of India

V shaped all steel boards, with their inherent stability to tide over obstacles and mud, interchangeability of starboard and portside boards are found to be superior to conventional flat rectangular boards for bottom trawling. These are cheaper in construction, offer less resistance and give longer service. Comparative trials with the two types of boards showed significant difference in tension between the boards but not in catch or horizontal opening.

Comparative efficiency of different surfaces for drying fish

The efficiency of four different drying surfaces, namely, cement platform, palmyrah leaf mat, aluminum tray and stretched net for drying fish were studied using sciaenids, mullet and perch. All the drying surfaces were found to be equally efficient. The cheaper and locally available palmyrah leaf mat or stretched net can replace costly cement platform and aluminium tray for efficient drying of fish.

Length-weight relationship of two palaemonid prawns, Macrobrachium idella and M. scabriculum: a comparative study

Length-weight relationships of two commercially important freshwater prawns, Macrobrachium idella and M. scabriculum, have been worked out separately for the two sexes of the two species. 't' test showed that growth departs significantly from the isometric growth in the case of both sexes of M. idella and in the female of M. scabriculum. Therefore, the cubic formula W = CL^3 may be applied only in the case of males of M. scabriculum. In all the other cases W = CL^n may be followed.

A comparative study of various extenders of milkfish, Chanos chanos (Forsskal) sperm preservation

Four chemical extenders in 7 different concentrations (potassium chloride, sodium chloride, glucose, sodium citrate, Ringer s solution, cow serum and milkfish (Chanos chanos) serum) were compared in the preservation of milkfish sperm. Results showed milkfish serum to be the most suitable of the various extenders tested. This may be attributed to suitable osmotic potential and/or presence of proteins which may have directly or indirectly influenced sperm viability. The effects of milkfish serum on the motility and fertilizing capacity of sperm at different durations of storage however need to be investigated.

Quality of cured fish on the west coast: comparative study with the IS specifications

Moisture and salt content in cured fish products from various centres on the west coast of India are compared. The moisture contents varied in samples from different centres, whereas the salt content remained more or less uniform. The deviations from the Indian standard specification were highly significant in both cases. The high mean moisture values and low salt values with respect to accepted standards are indicative of the improper drying and poor salting.

Comparative feature on design, construction and installation of three different model of low cost solar tunnel dryers

The study was conducted in collaboration with the ECFC project of the FAO (BGD/97/017) in Cox's Bazar to develop a low cost solar tunnel dryer for the production of high quality marine dried fish. The study areas were Kutubdiapara, Maheshkhali and Shahparirdip under Cox's Bazar district. Three different models of low cost solar dryer were constructed with locally available materials such as bamboo, wood, bamboo mat, hemp, canvas, wire, nails, rope, tin, polythene and net. Size of the dryers were: 20x4x3 ft ; 30x3x3 ft and 65x3x3 ft with the costs of Tk. 3060, 3530, 9600 for dryer 1, 2 and 3, respectively having different models. The drying capacities were 50, 150, 500 kg for dryer 1, 2 and 3 respectively. The average temperature range inside the dryers were 29-43°C, 34-51°C and 37-57°C for dryer 1, 2 and 3 respectively as recorded at 8:30h to 16:30h. The relative humidity were in the ranges of 22-42%, 27-39% and 24-41 % in dryer 1, 2 and 3 respectively. The fish samples used were Bombay duck, Silver Jew fish and Ribbon fish. The total drying time was in the range of 30-42, 28-38 and 24-34 hours to reach the moisture content of 12.3-14.5, 11.8-14.3, and 11.6-14.1% in dryer 1, 2 and 3 respectively. Among these three fish samples the drying was faster in Silver Jew fish followed by Bombay duck and Ribbon fish in all the three dryer.

A comparative study on the induced breeding and in vitro fertilization performance by various inducing agents in catfish, Heteropneustes fossilis (Bloch)

Brood catfish, Heteropneustes fossilis were collected from Tamirabarani river basin of Tamil Nadu, India and kept in cement tanks. Three inducing hormones viz, Ovaprim, Ovatide and WOVA-FH were injected at the rate of 0.5, 1.0, 1.5 and 2.0 ml/kg body weight in order to induce oocyte maturation and ovulation. After 10-13h of injection at a water temperature of 27±-0.5°C, stripping of eggs and in vitro fertilization was done. Ovaprim gave maximum (94.67%) hatching rate followed by Ovatide (90.33%) and WOVA-FH (77.33%).

Comparative effect of Pediococcus acidilactici and Lactococcus lactis on growth performance, survival and enzyme activity of western white leg shrimp (Litopenaeus vannamei)

This study was done in Shahid Kiani Marine Aquaculture Development Center, Choebde, Abadan in order to evaluate the effects of Pediiococcus acidilactici, Lactococcus lactis and vitamin C on growth performance, survival, enzymatic activities and immune responses of L. vannamei during three months. Treatments were included control group, Pediiococcus and Lactococcus treatments which fed with diet containing 1×10P9P cfu gP_1P bacteria and vitamin C. At the end of the experiment, the growth factors, immune parameters, digestive enzymes, intestinal, histology of intestine, carcasses and microbial flora (bacterial total count and lactic acid count) were evaluated. The results indicated that administration of lactobacillus had significant effects on the growth factors as the highest weight, increase specific growth rate, relative growth rate, feed conversion ratio and protein efficiency in the shrimps received pediococcus and then Lactococcus (P<0.05). The best immune function was also observed in the shrimps fed by probiotics, so that proteins and hemoglobin̛ hemolymph, phenoloxidase activity and challenged with V. parahaemolyticus showed a statistical difference comparing to the control group and the group received vitamin C (P<0.05). Some digestive enzymes, in pediococcus treatment showed a significant increase when compared to other treatments (P<0.05). Significant changes in bacterial intestinal flora were observed in probiotic groups compared with control and vitamin C groups (P < 0.05). Histological results showed the positive effects of probiotics in the gut (P < 0.05). While these supplements cannot caused to significant impacts on the shrimp carcass composition (P ˃ 0.05). As a result pediococcus group had the best performance among treatments.

Comparative study of seasonal changes in some blood parameters and genetic polymorphisms of serum antibodies and antigens on red blood cells surface in immature Caspian salmon

Seasonal sampling from 40 immature Caspian salmon were performed in summer, autumn, winter and spring. The maximum ranges of RBC counts, Hct, Hb, WBC count and clotting times were observed in spring, summer, spring, spring and winter, respectively. The minimum amounts of these factors were counted in summer, winter, winter, winter and winter, respectively. Blood Samples were taken from healthy smolt, immature and adult Caspian salmon in spawning time. Hematological determinations and biochemical serum analysis were performed in 101 fish in the three samples. The ranges of hematological values for sample mean were counted. Red blood cell counts were 866600 mm3 and 1259400 mm3 in smolt and adult respectively. Hematocrit was 48.39% in smolt and 44.29% in adult. Hemoglobin was 8.85 gr/dl in smolt and 10.91 gr/dl in adult. White blood cell count was 8781.58 mm3 in smolt and 5217.55 mm3 in adult and mean were differential of WBC, Lymphocyte 90.57%in smolt and73.22% in adult. Neutrophil was 5.12% in smolt and 16.92% in adult, Monocyte were 1.27% in smolt and 4.24% in adult, Clotting time was 282.34 Seconds in smolt and 291.47 seconds in adult MCV, MCH and MCHC also meagered in smolt and adult. Biochemical parameter in immature and mature Caspian salmon meagered .Glucose concentration was 2.97 mmol.l- in immature and 1.99 mmol.l- in mature .Cholesterol concentration was 4.26 mmol.l- in immature and 7.06 mmol.l- in mature. Triglyceride amount was 2.35 mmol.l- in immature and 2.47 mmol.l- in mature and Calcium was 2.47 in immature and 2.61 mmol.l- in mature. An in situ study was made on erythrocytic isoantigens and hetero-antigen and their corresponding iso-and hetero-antibodies of sera by means of hemoagglutination tests on the blood sample, of 450 immature and 50 mature Caspian salmon. The absence of erythrocyte iso-antigens and hetero-antigen and their corresponding iso-and hetero-antibodies were shown by the experimental. It could be indicated an intra-specific variation and differences in species for kelardasht hatchery.

A comparative study on effects of Immunoster and Immunowall as immunostimulants on some hematological, biochemical and growth indices of farmed great sturgeon juveniles (Huso huso)

Prebiotics are non-digestible food ingredients that profitably affect the host by selectively stimulating the growth and /or activation of one or a limited number of bacteria in the intestine that can enhance host health status. Immunoster (IS) and Immunowall (IW) are prebiotics and immunostimulants derived from the outer cell wall of brewers yeast, Saccharomyces cerevisiae. These substances contain MOS and �-glucans. After a four-week acclimatization period to rearing conditions and basal diet, 450 farmed great sturgeon juveniles weighing 95.58 ± 9.38 g were randomly distributed into 15 fiberglass tanks (2 × 2 × 0.53 m) in five treatments (Control, IS 1%, IW 1%, IS 3%, and IW 3%) in three replicates (completely randomized design) and kept at a density of 30 fish per tank for a period of 8 weeks at water temperature 20.55 ± 5.11ºC, dissolved oxygen 6.73 ± 0.35 mg L-1 and pH 7.92 ± 0.09. IS and IW were added at two levels of 1% and 3% to the basal diet in place of cellulose, except the control. At the beginning, in the middle and at the end of the trial, carcass analysis was done to determine the moisture, protein, fat, ash, and total carbohydrate. Also, blood samples were collected to measure hematological, biochemical and immune indices. At the end of the trial, final weight, final length, body weight increase (BWI), specific growth rate (SGR), average daily growth (ADG), protein efficiency ratio (PER), feed conversion ratio (FCR), and condition factor (CF) in fish fed on IS and IW in both levels 1% and 3% showed some differences. These differences were significant in IS 3% and IW 1% and 3% compared with the control (P<0.05). HSI showed no significant difference (P>0.05) and survival rate was 100% in all treatments. Crude protein of carcass in fish fed on IS and IW at 1% and 3% showed an increase in comparison with the control. There was significant difference between IS 3% and the control in crude protein of carcass (P<0.05). Fish fed on IS and IW at 1% and 3% showed various results in hematological and biochemical factors. It was observed significant difference in MCV between IW 1% and IS 3% compared with the control (P<0.05). Although there was an increase in values of hematocrit, hemoglobin (except IS 1%), WBC (except IW 3%), MCH, neutrophil, total protein, albumin (except IS 3%), K+, and lysozyme in fish fed on IS and IW compared with the control, it was no significant (P>0.05). The maximum count of WBC and the highest value of Ca2+ were seen in IW 1%. The maximum count of lymphocyte, the highest values of total protein, albumin and IgM were recorded in IW 3%. IS 1% had the maximum count of neutrophil and the highest concentration of lysozyme. Based on obtained results, it can be declared that IS and IW at two levels of 1% and 3% can enhance growth performance and feed efficiency and also improve some hematological, biochemical, and immune indices in farmed great sturgeon juveniles.

A comparative ecological study on internationally important wetlands of Khoor-e-Kolahy and Tiab

Ecological study on Kolahy and 'flab estuaries were carried out during 1996-1997. Water and sediment sampling was done seasonally. In order to study the physical and chemical characteristic of the water, various animal fauna from different material niches including planktons and fish from water, benthousi from the sediment , and surface living animal such as Arthropod (Crabs) and Waterbirds were identified. I he result shoved, that water salinity of both estuaries was the same as the general salinity existing its the Persian Gulf water, and its variation is same IN those waters Minimum water salinity in both estuaries are seen during Bahairdan or early winter mooth(Jaa.), which is about 31ppt and Maximum is during .rirldlun.) or summer mouth at about 19 ppt. Dissolved otygen and pH are slime as the general Persian Gulf waters., Dissolve Oxygen being directly associated to temperature and its fluctuation is between 7- Sing/I and pH between 7.5-LS. The animals of both estuaries are almost similar having a sal factory species diversity . The birds of the region are often seasonal migrants , the maximum population of which occurs in winter season and the minimum during summer month. Nam coverage is richer in Tiab than Kolahy estuary, where in Kolahy a signal Mangrove tree is in exigence. 'Ile total coverage of Mangrove forest in Tiab is estimated about -29 hec.Both estuaries are included with in the international Ramsar Convention sites in 1971. Due to national importance of these estuaries inproviding refugee for various birds species and also hinting grounds and access traffic for local fishing vehicles, Actiog as an important access for various inhabitancy living with these area of the Persian Gulf. Due to importance or prawn aquacultur for the economical well being of local inhabitance, these areas provide a suitable grandees for prawn production. I-test statistics show, there are no significant difference among various invertebrate and vertebrate animals. In over all out look 21) phytoplankton genera, 21) zeoplankton genera 17 miafauna and 32 roaerofauna genera , 11 different species Carcineacearions and 119 species of walerbirds were identified with in the Tiab and Kolahy estuariesregioos. The X statistic show that the animal density is directly associated to season. Where density of miofauna and maerofauna in both estuaries are in maiticrourn during summer and the minimums existing during the winter season. In addition the bentic invertebrate population density in closlly association to birds population density since , the later, feeds on the former animals. Where the increasing in bird population density during the winter season, the bentic invertebrate animal population density decreases. The over all trend of animal population density in winter tend to increased towards the summer seasons, which this is due to climatic conditions of the region. The bird population on the contrary to other animals of both estuaries tend to increase from summer towards the winter seasons and which this bird population density is in maximum in winter with in the region.