Recent advances and scope for sea farming in India

Although brackishwater prawn and fish culture was traditionally practiced for a long time in the country, efforts at sea farming are still in their infancy. During the past 15 years the Central Marine Fisheries Research Institute has developed various technologies for sea farming of mussels, pearl oysters, production of cultured pearls, edible oysters, clams, prawns, lobsters, seaweeds and more recently sea cucumbers and top shells. The paper outlines recent developments in these areas as well as in others like sea ranching of marine prawns and pearl oyster, and scope for enlarging sea farming activities including development of artificial reefs in India.

Probabilistic fault identification using vibration data and neural networks

Bayesian formulated neural networks are implemented using hybrid Monte Carlo method for probabilistic fault identification in cylindrical shells. Each of the 20 nominally identical cylindrical shells is divided into three substructures. Holes of (12±2) mm in diameter are introduced in each of the substructures and vibration data are measured. Modal properties and the Coordinate Modal Assurance Criterion (COMAC) are utilized to train the two modal-property-neural-networks. These COMAC are calculated by taking the natural-frequency-vector to be an additional mode. Modal energies are calculated by determining the integrals of the real and imaginary components of the frequency response functions over bandwidths of 12% of the natural frequencies. The modal energies and the Coordinate Modal Energy Assurance Criterion (COMEAC) are used to train the two frequency-response-function-neural-networks. The averages of the two sets of trained-networks (COMAC and COMEAC as well as modal properties and modal energies) form two committees of networks. The COMEAC and the COMAC are found to be better identification data than using modal properties and modal energies directly. The committee approach is observed to give lower standard deviations than the individual methods. The main advantage of the Bayesian formulation is that it gives identities of damage and their respective confidence intervals.

Feasibility of damage detection using vibration data in a population of cylinders

The feasibility of vibration data to identify damage in a population of cylindrical shells is assessed. Vibration data from a population of cylinders were measured and modal analysis was employed to obtain natural frequencies and mode shapes. The mode shapes were transformed into the Coordinate Modal Assurance Criterion (COMAC). The natural frequencies and the COMAC before and after damage for a population of structures show that modal analysis is a viable route to damage identification in a population of nominally identical cylinders. Modal energies, which are defined as the integrals of the real and imaginary components of the frequency response functions over various frequency ranges, were extracted and transformed into the Coordinate Modal Energy Assurance Criterion (COMEAC). The COMEAC before and after damage show that using modal energies is a viable approach to damage identification in a population of cylinders.

A cohesive approach to thin-shell fracture and fragmentation

We develop a finite-element method for the simulation of dynamic fracture and fragmentation of thin-shells. The shell is spatially discretized with subdivision shell elements and the fracture along the element edges is modeled with a cohesive law. In order to follow the propagation and branching of cracks, subdivision shell elements are pre-fractured ab initio and the crack opening is constrained prior to crack nucleation. This approach allows for shell fracture in an in-plane tearing mode, a shearing mode, or a bending of hinge mode. The good performance of the method is demonstrated through the simulation of petalling failure experiments in aluminum plates. © 2005 Elsevier B.V. All rights reserved.

East African Freshwater Fisheries Research Organization Annual Report 1972

Feeding habits of many animals have been used widely in animal classifications. This is so, because the type of diet an organism requires demands structural specialisation which will utilise the available resource. Many animals may however have many structural modifications to enable them to be described as omnivourous or generalised feeders such as H. empodisma and H. riponianus (GREENWOOD 1960) which may show varying degrees of structural and adaptational intermediacy between two trophic groups. Generally, however, the diet of many animals including fish changes as the animal grow larger. The change in structural modifications is usually correlated with changes in the diet. In fishes the change may involve change from tricuspid to biscuspid and finally to unicuspid type of teeth. The degree of modification in the structure depends on the diet, thus Haplochromis that feeds on soft tissues of snails only requires modifications in oral dentition while Haplochromis that feeds on both soft tissues and shells of snails require modification in the lower pharyngeal bone for grinding purposes. Other modifications connected with food utilisation may be located in the alimentary canal. (I) The fish species that are commercially exploited are Protopterus aethiopicus, Clarias mossambicus, Tilapia esculenta, Tilapia amphimelas and Tilapia hybrids. The other fish species present in the lake but not commercially exploited are: Gnathonemus sp. Alestes sp. Labeo sp., Barbus paludinoses, Barbus jacksoni, Barbus lineomaculatus, Barbus regersi, Leptogrlanis sp., Schilbe sp., Haplochromis spp. and Hemihaplochromis sp. (2) Protopterus sp. and Clarias sp. are mostly caught with hooks on long lines. There has been a steady increase in number of hooks on the lake. Since the stocks of Protopterus and C/arias in the lake have a limit, we should control the number of hooks used by each of the fishermen in order to avoid overharvesting. (3) All the previous studies on Lake Kitangiri fisheries suggested the use of gill nets with mesh size greater than 88.9 mm in order to avoid the capture of immature Ti/apia spp. But if the fishermen are to obtain economic gains from the fishery, the optimum mesh size for use is 88.9 -101.6 mm. (4) The gillnet is a passive gear with very beneficial selective characteristics. Unfortunately the drive-in fishery which exists on Lake Kitangiri more or less destroys the gillnet selectivity characteristics. It is therefore recommended that the beating of water with poles be discouraged and stopped. (5) There is need for provision of stable fishing canoes to replace the unstable bottle palm dug-out canoes which are currently being used and which are very risky to operate. (6) The fish processing facilities on Lake Kitangiri are still inadequate. Most of the fish is sun dried, Since sun drying is very difficult during the rainy season, most fishermen carry out intensive fishing during the dry season, Concentrating most of the fishing effort in anyone season instead of spreading evenly this effort over the whole year could damage the age structure of the exploitable stocks. (7) There are considerable fluctuations in the volume of water of the lake. The feasibility of regulating the water loss through the effluent Sibiti river should be investigated by the Water Development Department. (8) Damming the Sibiti river is an expensive undertaking and therefore, the Rural Development Bank of Tanzania should be asked to assess the economic feasibility of such a project.

Coastal development and pollution impact on the distribution of macrobenthic communities along the eastern coast of the Gulf of Suez (Egypt)

The configuration for the eastern side of the Gulf of Suez was studied over 241 km from Ras Mohammed to Ras Sudr including 35 station. Litters, tar balls and aged oil patches aggregated in considerable amounts on the beach and shore line of the middle part due to the oil spills from off-shore oil wells. A large reef flat in the shallow intertidal waters exists at stations 1 and 2 (Ras Mohammed, Protected area) and spars coral patches are less frequent at the Stations from 7 to 13. Density and diversity of marine benthos were higher on hard and cobble bottoms compared to muddy sand and sandy substrates. The assemblages of the benthic fauna are dominated by the gastropod Courmya (Thericium) vulgata; the bivalve Brachiodontes variabilis, and the barnacles Chthamalus stellatus, Balanus amphitrite and Tetraclita rubescens. The distribution of the algal cover in the intertidal region shows high abundance of the brown algae, Sargassum latifolium; padina pavonica and Cystoseira trinodis rather than the green and red algae. These species are found in both polluted and unpolluted areas. The changes in benthic structures in the study area depend not only on the state of pollution but also on the type of substrates.

Studies on mollusca of Saurashtra coast - I. (Amphineura and Gastropoda)

Proximate composition of 19 species of marine Gastropoda and one of marine Amphineura have been studied. Seasonal variations in proximate composition of the meat of gastropods, Thais rugosa (Born), are reported. Majority of the gastropod species have high protein and ash contents.

Ecological risk assessment of pollution in sediment on benthic fauna in coast of Bandar Abbas

Ecological risk assessment is determination of the probability of an adverse effect occurring to an ecological system. This investigation was carried out to assess the ecological risk of sediment in coast of Bandar Abbass in 9 stations including Shilat Jetty, Hotel Amin, Poshte-Shahr, Souro, Bahonar Jetty, Powerhouse, Refinery and Rajaee Jetty from autumn 2013 to summer 2014. Results showed that Polychaete with 1177 , 1109 , 414 , 573 , ind.m2 in autumn 91 , winter 91 , spring 92 and summer 92 were the most abundant in frequency respectively. Among ecological indices, the Margalof that ranged from 4 to 7 was in a good situation while Shanoon and Berger – Parker with 1.2 (at most) and 0.32 (at least) respectively indicated an environment with probable stress. Heavy metal distribution obtained as Cd>Pb>Cu>Zn in sediment. In tissue, the distribution of heavy metals were as Crab>polychaete>Bivalve>gastropod for Pb, Gastropod>Bivalve>Polychaete>Crab for Cd, Gastropod>Crab>Polychaete>Bivalve for Cu and Gastropod>Bivalve>Crab>Polychaete for Zn. Maximum and Minimum of TOM obtained 10.16 and 1.96 percent in Posht-e-Shahr and shilat Jetty respectively and clay was the dominant grain in most area. Bioaccumulation coefficient of Zn and Cu was high in all stations. Igeo as a single index was high for Cd indicating a high risk in all stations. Potential Ecological Risk was high for Cu and Zn and goes increasingly from shilat Jetty to Rajee Jetty but goes down for Pb. Pollution index for Cu and Pb was nearly the same as Potential Ecological Risk but for Zn goes constantly. Among PAH, 5-ring and 6-ring PAhs were more concentrate comparison to other compounds in sediment. 2-ring and 3-ring, 3-ring, 4-ring and 5-ring and 5-ring PAHs were more concentrate in Gastropod, Bivalve, Crab and Polychaete respectively. HI as an index of PAH obtained 1. Ecological Risk Indices showed that the heavy metals are a serious risk for invertebrate in sediment but PAHs are not a risk for benthic community.

Abundance and composition of benthic fauna in Penaeus monodon Fabricius culture pond on the west coast of Malaysia peninsular

This paper reports a study on the benthic faunal abundance and diversity of tiger shrimp P. monodon culture ponds in Perak, west coast of Malaysia Peninsular. Sampling was carried out at three weeks interval throughout the 116 days culture period. In addition, water temperature, dissolved oxygen, salinity, transparency, pH and organic matter of soil were also measured. Results showed that the major groups of macro-benthos comprised of gastropod, foraminifera, polychaetes, bivalve and insects; whereas the meio-benthos comprised of harpacticoid copepods, ostracods, nematodes, gastropods, foraminifera, bivalve, insects, crustacean nauplii and polychaetes. In macro-benthos, the abundance of different sizes of Gastropods increased throughout the culture duration. This consisted of 37-98.20% for <1cm length, 1.80-61.50% for 1-2cm length and 1.18—1.30% for >2cm length. Other macro and meio-benthic organisms decreased linearly with the culture period. The depletion symptom indicates that the culture species may have intensively preyed upon the consumable (<0.5cm in size) benthic fauna together with detritus and artificial diet; or could have been caused by pond bottom deterioration via uneaten feed, faces and toxic gases.

Impacts of environmental conditions on macrobenthic distribution along the Suez Gulf, Egypt

Increases in coastal development and human activities leading to sedimentation degrade the quality of water; disturb the natural structure and functions of aquatic communities. The Suez Gulf is a large semi-closed area (~625 km long coastline).The assemblages of bottom fauna were studied qualitatively and quantitatively in the shallow intertidal waters along the western coast of the Suez Gulf. The quality of seawater and sediment structures were analyzed. The distribution of macro-benthos included a total of 38 species of Gastropoda and 9 Bivalvia; and 25 species from the other invertebrates included 7 groups namely, Rhizostoma, Polychaeta, Cirripedia, Amphipoda, Isopoda, Decapoda and Echinodermata. The most dominant group among invertebrate groups was the Polychaeta which included 4 species: Hydroides elegans, Perinereis cultilifera, Perinereis nuntia and Ophelina acuminata. The Cirripedia were represented by 3 species namely, Balanus amphitrite, Chithamalus challengeri and Tetraclita squamosa. The variations in the numerical abundance and biomass of bottom fauna studied between the observation periods and at sampling sites. There was a marked increase in benthos biomass at St. IV (Ras Gharib) yielding an average of 318.8 g/m² in which the gastropod community represented the dominant species in collected samples reaching 270.28 g/m² (84.4% of the total biomass) and numerically numbered 116 ind./m². Veliger larvae of bivalves and gastropods appeared to be present in the plankton for long periods and their production seems to be continuous throughout the year. In the intertidal zone of the Suez Gulf, the values of pH varied within narrow limits. Water temperature and salinity seemed to be important in the distribution and abundance of the macro-benthos communities in the study areas. The organic content in shallow intertidal waters and sediments indicated high values in the central part of the Gulf of Suez.

First record of a spindle cowry Crenovolva (Ovulidae, Gastropoda) from Bulleji, Karachi, on the gorgonian coral Muricella sp. and with a note on their association

Attached to hard substrata on our shores occur the branching colonies of gorgonian corals of the genus Muricella (Fig. 1A, Pl. 1B, C, D). Since there is no report on this genus from Pakistan this report be taken as the first record from here. The family Ovulidae comprises several hundred species of marine gastropods, all of which appear to be obligate associates of cnidarians as stated by Robertson (1970) and Hadfield (1976); the present ovulid gastropod genus Crenovolva lives exclusively on the gorgonians (Morton, 1989). Tirmizi and Zehra (1984) recorded thirty-two families of gastropods from Pakistan, but not any representative of the Ovulidae, so the material at hand may be the first record from Pakistan. Since we are unable to reach to specific level the material is being reported as unspecified.

Biology and distribution of grouper (Epinephelus coioides) in province waters (Abadan Bhrakan)

This survay has been done from Januray 2000 till May 2002 in Khouzestan costal waters. Four species of grouper were identified from which orange spotted grouper (Epinephelus coioides) was the dominant species. For studing environmental parameters and reproductive biology, age, growth parameters and mortality rate samples were collected by fishing ship. Samples were taken montly in 4 days by fishing traps and trawls. In addition, some samples were obtained from Khozestan fish landing centres. Environmental factors such as PH, 02, salinity, water temperature and depth of traping areas, were measured. To identify species, morphometric characteries of 452 individal fishes were measured. Stomach contents of 394 fish were has survaid, from which stomach of 226 fish, and 168 fish had empty stomachs. Percentage of empty stomachs (cv) in males was more than females. Food items found in 73 percent of stomach were crab (11%), shrimps (8.8%) , squids (3.9%), gastropods (17%) and bivalves (0.4%). Feeding intensity in year classes did not obay logic trends The importance relatively indicator (I.R.I) were 81, 9.9, 4, 1.5 and 0.3 percent for fish, crab, shrimp, squid, gastropod and bivalve respectively. For age determination, sagita otoliths of 450 fish were taken and countable sections were obtained from 425 specimens. Relative frequency distribution of opaque and transparent rings showed that each opaque growth ring generates once a year from November to September. It seemed that generation of opaque rings is affected by temperature and photoperiod changes. Correlation between length and age was calculated using Von Bertalanffy's least square method. Following equasion was obtaind: L(t) : 122.27 (1 e 0.146 (t+0.482)) Growth parameters were determined through by Ford Walford equasion and Response Surface and Shepherd subcommands in Elefan program and L00 and K amounts were have determined. Correlation between length and age of 635 fish was determined by gender . Length and age correlation was calculated by exponential model and between total length and standard length by straghit line model. Correlation between age and weight of sagita was calculated by total length and age. The most Correlation was between sagita weight and fish age (r=0.876). Total mortality rate (z) was estimated by Length Converthed Method , Jones and Vanzaling and Powel Wetherall. Total mortality rate was z=0.39. Natural mortality rate, using Pauly method was calculated M=0.32. Fishing mortality (F) was 0.08. Gonads of 425 fishes were surveid within 18 month, from which 363 were female, 46 were male and 16 were sex reversing individuals .Total length of females varied from 26 to 95.5 centimeters while males length varied from 56.5 to 107 centimeters. Sex reversing individuals had a length of 47.5 centimeters, when two years old and 62.5 centimeters at age of 3 years. From the mentioned 425 fish, 401 individuals were matured, containing 339 females and 62 males, 5.47 females against each male. Montly changes of Gonadosomatic Index (GSI) by total body weight and standard length and total body length showed that this index increases from march to May and maximum increase was in May . This experiment was adapted in spawning season. Potential, relative, and absoulate fecundity was estimated by counting eggs in three samples. Total amount of traped fish using special traps was 16182.18 kg from which Epinephelus coioides provided catching 15353.43 kg of it (91.27 %) and By catch was 141.18 kg (8.24 %). Total average CPUE for whole catch was 123.33 kg/day/vessel. Total amount of catch was estimated 232.04 tons, considering CPUE of total catch and total Khuzestan trap ships effort.

International Workshop on Fluid-Structure Interaction. Theory, Numerics and Applications

... Fluid-Structure Interaction Simulation of Viscoplastic and Fracturing Thin- Shells Subjected to Underwater Shock Loading Ralf Deiterding, Fehmi Cirak, ...