POLYCULTURE OF SCALLOP CHLAMYS FARRERI AND KELP LAMINRIA JAPONICA IN SUNGO BAY

Several polyculture models of scallop Chlamys farreri and kelp Laminaria japonica currently employedin Sungo Bay and other parts of northern China are described in this paper. Economic benefits of differ-ent polyculture models are analysed based on the growth rate, culture density and market price. In addi-tion, site selection, critical environmental conditions and polyculture problems are discussed in detail.

SUMMARY OF STUDIES ON CLOSED-POLYCULTURE OF PENAEID SHRIMP WITH FISHES AND MOLUSCANS

Closed polyculture of Chinese penaeid shrimp,Taiwan red tilapia ,and molluscans(constricted tagelus and bay scallop) was studied from 1995 to 1997 with the enclosure experiment method, on a shrimp farm in Haiyang County,Shandong Province. Four structure optimized closed polyculture systems, i.e., the “shrimp tagelus" system, the “shrimp scallop" system,the “shrimp tilapia" system and the “shrimp tilapia tagelus" system,were worked out. All these polyculture systems were superior to shrimp monoculture system in economic and ecological efficiencies. The order of these polyculture systems in efficiencies was “shrimp tilapia tagelus">“shrimp tagelus">“shrimp tilapia">“shrimp scallop". The “shrimp tilapia tagelus" system raised the production by 28% and the utilization efficiency of input nitrogen by 85%.These closed polyculture systems reduced the nitrogen discharge ratio to 6%-8%, instead of 40%-90% in the usual open culture systems. The ecological features of the systems were also investigated and many meaningful results have been obtained. The mechanism enhancing the efficiencies of these systems, the ways to enhance the efficiencies further and those to reuse the sedimented materials are disscussed.

Trophic Interaction in a Portunus rituberculatus Polyculture Ecosystem Based on Carbon and Nitrogen Stable Isotope Analysis

Trophic interaction among various biomass groups in a swimming crab Portunus trituberculatus polyculture pond was investigated using carbon and nitrogen stable isotope analysis. The polycultured animal species also included white shrimp Litopenaeus vannamei, short-necked clam Ruditapes philippinarum, and redlip mullet Liza haematochila. The mean δ^(13)C value for all the biomass groups in polyculture ecosystem ranged from -25.61‰ to -16.60‰, and the mean δ^(15)N value ranged from 6.80‰ to 13.09‰. Significant difference in the δ^(13)C value was found between particulate organic matter(POM) and sediment organic matter(SOM)(P < 0.05), indicating that these two organic matter pools have different material sources. Assuming that a ^(13)C-enrichment factor of 1.00‰ and a ^(15)N-enrichment factor of 2.70‰ existed between consumer and prey, diets of the four cultured animals were estimated using a stable isotope mixing model. The estimated model results indicated that P. trituberculatus mainly feed on Aloidis laevis; L. vannamei mainly feed on shrimp feed; while A. laevis, R. philippinarum and L. haematochelia mainly feed on POM. Shrimp feed was also an important food source of R. philippinarum and L. haematochelia. The diets of P. trituberculatus, L. vannamei, R. philippinarum, and L. haematochila showed complementary effects in this polyculture ecosystem. Our finding indicated that the polyculture of these four organisms with suitable farming density could make an effective use of most of the food sources, which can make a highly efficient polyculture ecosystem.

Production of Pacific White Shrimp Polycultured with Swimming Crab at Different Densities, and Nutrient Budget in the Enclosure System

This study was to evaluate the effect of stocking densities on the nitrogen and phosphorus budgets for a polyculture of the crab Portunus trituberculatus and the Pacific white shrimp Litopenaeus vannamei.The shrimps(initial weight,0.012 g)were cultured at a density of 45 shrimp m^(-2),and juvenile crabs(initial weight,0.024 g)were cultured at five densities of 0,3,6,9,and 12 crabs m^(-2).The treatments were grouped as C0S45,C3S45,C6S45,C9S45,and C12S45,respectively.Water quality parameters,growth of shrimp and crabs,and nitrogen and phosphorus budget were measured.The results indicated that the shrimp performances in polyculture treatments C3S45 and C6S45 were superior to those in the crab-free treatment(C0S45).The crab in treatments C3S45 and C6S45 exhibited a significantly higher final mean weight and carapace width/length than those in treatments C9S45 and C12S45.The final size and survival of crabs had a negative correlation with the increasing crab stocking density.The contents of total phos-phorus and total nitrogen and the comprehensive contamination index values were higher in the C9S45 and C12S45 treatments than in the other treatments.The conversion ratios of nitrogen for crab and shrimp growth in treatment C3S45 were significantly higher than those in the crab-free treatment.These findings indicate that polyculturing shrimp with crabs at suitable densities can improve productivity,profitability,nutrient utilization,and the environmental quality.From the 60-day treatments,the optimal culture densi-ties were 3-6 crabs m^(-2) and 45 shrimps m^(-2).

CARBON CYCLE IN SHRIMP POLYCULTURE MESOCOSM

The carbon cycle in shrimp polyculture mesocosm ecosystems was studied in the shrimp farm of the Huanghai Fisheries Group Corporation in Shandong Province from May to August, 1997. The results showed that the plankton community respiration rate fluctuated between 0.07 and 2.28 mgC/(L·d), average of 0.82±0.42 mgC/(L·d), which was 49 percent of the rate of phytoplankton gross production;that the average respiration rates (mgC/(L·d)) of micro , nano and pico plankton were 0.07, 0.38 and 0.31, which were 175, 30 and 207 percent of the corresponding sized phytoplankton production rates; that the sediment respiration rate (mgC/(m 2·d)) varied from 178.64 to 373.23, average of 262.60±48.68, and increased gradually with the lapse of culture time; and that the organic carbon accumulation and the respiration in the sediment of the shrimp monoculture mesocosm was higher than that in the polyculture mesocosms. The total sediment respiration per 25 m 2 mesocosm in the culture period averaged 571.16 gC, which was 10 percent of the total organic carbon input of the mesocosm.

Organic carbon budget in shrimp polyculture enclosure ecosystems

The organic carbon budget in shrimp polyculture ecosystems was studied with five experimental enclosures. The results showed that: (l ) the total Organic carbon income of the ecosystems varied from 4 847. 46 to 6 154. 67 g, averaged (5 646. 94 t 551.09) g, the average ratio among its components, i. e., (phytoplankton production ): (periphyte production ): (feed casted) was 0. 73: 0. 11: 0. 16; (2) the total output of organic carbon varied from 3 310. 28 to 3 974. 79 g, averaged (3 644. 21 281. 44) g, the average ratio among its components, i. e., (plankton community respiration): (periphyton respiration): (benthic community): (culture animal production): (culture animal respiration) was 0. 53: 0. 19: 0. 15: 0. 04:0. 09; (3) the organic carbon accumulation varied from 1 383. 45 to 2 707. 31 g, averaged (2 002. 73 546. 76) g, which was 26% --44 % of the total organic carbon income; the sequence of organic carbon accumulation in the ecosystems of different polyculture types was Y5 (Penaeus chinensis -- Argopecten irradians) > Y7 (P. chinensis -- Taiwan red tilapia) > Y4 (P. chinensis ) > T5 (P. chinensis -- Taiwan red tilapia -- Sinonovacula constricta ) > Y6 (P. chinensis S. constricta ); (4) the average conversion rate of organic carbon income to P. chinensis was (l. 77 0. 62) % (Y6>T5 > Y4 >YS > Y7), and that to total culture animals was (2. 18 0. 79) % (T5 >Y6 > Y5 > Y4 > Y7).

A study on the polyculture of the algae, the shrimp and the crab

A study was made on the polyculture of the red algae Gracilaria tenuistipitata Chang et Xia f. Liui Zhang et Xia, f. nov. , the shrimp Penaeus penicillatus Alcock and the mud crab Scylla serrata (Forskal) . The photosynthesis of the algae produces the oxygen on which the shrimp and the crab breathe. The algae are the reproductive place of the organism for the food of the shrimp and the carb, also is the shelter of the shrimp and the crab. The shrimp and the crab regard the algae as the vegetable

The Potential for Homestead Pond Polyculture of Tilapia and Carps in Coastal Bangladesh

A fishers’women-led Participatory Action Research(PAR)was conducted in 30 homestead ponds to assess the potential for polyculture of Tilapia(Oreochromis niloticus)and major carps Rohu(Labeo rohita)and Catla(Catla catla)in two coastal fishing villages of Bangladesh.Three treatments,namely T1(Tilapia 200 fish per decimal;1 decimal=40 m^2),T2(Tilapia 200+Rohu 32+Catla 8 fish per decimal)and T3(Tilapia 200+Rohu 8+Catla 32 fish per decimal),each with 5 replicates,were tried in Hossainpur and Anipara villages.Formulated commercial Mega-feed was applied to the ponds twice daily at an initial rate of 10%body weight(bw)/day of Tilapia down to 4%bw/day throughout the culture period.The water quality parameters of ponds including transparency,salinity and dissolved oxygen significantly varied among treatments except temperature and pH and remained within optimum range for carp polyculture except salinity.The survival rate,harvesting weight and yield of Tilapia were significantly highest in T1(85.63±05%,258.59±18.76 g&11073±805 kg/ha,respectively)in Anipara and lowest in T3(75.63±0.37%,136.97±10.63 g&5180±406 kg/ha,respectively)in Hossainpur.The gross fish production was the significantly highest in T1(11354±806 kg/ha)of Anipara and lowest in T1(6325±227 kg/ha)of Hossainpur.Statistically,the highest net return(866,627±84874 BDT/ha)was found in T1 of Anipara and lowest in T3(279,389±46104 BDT/ha)of Hossainpur with a significantly higher benefit-cost ratio(BCR)obtained in T1(3.26±0.20)for Tilapia and lower in T3(1.58±0.10)for polyculture Tilapia and carp of Hossainpur.Therefore,it may be concluded that Tilapia production in small homestead coastal ponds has a higher potential than its mix with carps in polyculture for generating food and supplemental income opportunity for coastal fishers’women in Bangladesh.

Effect of polyculture of shrimp with fish on luminous bacterial growth in grow-out pond water and sediment

Objective:To study the distribution of marine luminous bacteria in shrimp culture systems of West Bengal and the effect of polyculture of shrimp with fish to reduce luminous bacteria.Methods:Luminous bacterial counts were enumerated by spread plating on seawater complex agar from shrimp grow-out pond water and pond sediment samples of West Bengal,India.Results:About 31.16%and 51.44%of pond sediment and pond water samples respectively had detectable levels of luminous bacteria.It was noticed that in normal ponds a shift happened in bacterial profile of water from the day of flooding up to 60 d,with the dominance of luminous bacteria among vibrios,reaching counts 10^(4) cells/mL or more.While in diseased ponds,luminous bacterial abundance within the ponds was noticed in the first 6 weeks of culture.Marked reduction in luminous bacterial counts of water and sediment was observed through out the culture period in polyculture ponds compared to monoculture ponds.There was no incidence of white spot syndrome viral disease and luminous vibriosis in both controlled and experimental ponds.Conclusions:The results suggest vigilant monitoring of ponds for luminous bacteria abundance and polyculture of shrimp with fish in ecofriendly sustainable aquaculture can reduce the impact of shrimp disease outbreak.

Current status of poly culture and rotation culture in Chinese mariculture industry

The status of polyculture and rotational culture in Chinese marine life is reviewed. Some successful experience is summarized.

Avian Community Density and Distribution Patterns among Nicaraguan Conventional and Organic Shade-Coffee Plantations

We used a distance-sampling survey method and multivariate statistics to obtain a unique estimate of bird species density and seasonal variation in shade-coffee plantations. Our aim was to determine which cultivation practices among plantations contribute most to bird abundance. We conducted avian species counts at 200 points distributed across 10 shade-coffee plantations bordering the lower slopes of the Mombacho Volcano Natural Reserve, in western Nicaragua. We measured vegetation structure (coffee plants and overstory). We used principal components analysis (PCA) among 14 habitat variables to derive a single phyto-geoclimate summary measure (PGSM). We also used PCA to derive an avian abundance summary measure (AASM) from three bird survey variables, which proved to be a good predictor of bird density. We found higher bird species densities (AASM) in organic and traditional polyculture shade coffee plantations whose structurally complex and diverse overstory could be verified by PGSM. However, this finding was true only for birds that were habitat specialists. Our results provide further evidence for promoting organic coffee cultivation practices that maintain a structurally diverse overstory and help retain avian species richness and abundance in coffee plantations.

A preliminary assay on the mixed culture of red Florida tilapia and freshwater prawn <i>Macrobrachium americanum</i>stocked in outdoor tanks at different tilapia densities

Red jumbo tilapia and M. americanum prawns were placed in 1000 L units in polyculture at three different densities of tilapia (4/5, 9/5 and 14/5 m2;tilapia/prawn) during 112 days with initial weight of? 6.5 ± 2.8 g for tilapia and 25.9 ± 8.5 g for prawn. Prawn (0/5 m2) and tilapia (4/0, 9/0 and 14/0 m2) controls were included. Tanks were maintained outdoors and under shade. Total weight gain (WG), daily individual weight gain (DWG), specific growth rate (SGR), survival, production of gross mass and food conversion ratios (FCR), ammonia, nitrite and nitrate, and chlorophyll a were measured in all units. Only prawn weight gain was significantly higher in polyculture. For tilapia, the highest survival at the end of the trial was 94% and the lowest was 75%, while prawns had final survival rates from 43% to 86%. No statistical differences were observed in weight increase among treatments at p ≤ 0.05.

Culture Dynamics across the World Today:Tourism and the Palette of Imagination

In general,this manuscript critiques the contemporary dynamisms of the formation/deformation of the cultural sphere under the increased mobilisations of globalization.In particular,it inspects the symphysis[□SYMPHYSIS]between'tourism'and'culture',where the latter stands as an immense portmanteau phenomenon embracing many different things(under the vicissitudes of globalisation/glocalisation)across the protean realms of race,gender,entertainment,consumerism,meaning-making,et cetera.Critiquing Jamal and Robinson's recent attempt at panoramic coverage of the geography of tourism/tourism studies),it argues that tourism is regularly implicated in cultural practices relating to power-exercises in/across society.Then,in synthesising Bauman’s vision of contemporary society as that moving from seemingly well-ordered stabilities to a geographic realm where change is the-only-permanence and uncertainty the-only-certainty,the manuscript generates five lead propositions calling for'plural knowability',viz.,for a deeper/richer palette-of-imagination on the teeming multiplicities and throbbing provisionalities of culture as it emerges/unfolds or otherwise gets recast under the destabilising'nomadic logics'of our time.In viewing culture as a vehicle of both'impermanence'and'seduction'nowadays,the paper notes how in so many places and spaces,individuals are less inclined to be engaged locally/regionally/nationally as culture-partly through the volatile iterability of travel/tourism-has become an ever-widening polylogue.

Conservation aquaculture of Ompok bimaculatus (Butter catfish), a near threatened catfish in India

The butter catfish,Ompok bimaculatus,belonging to the silurid family,is widely regarded as an important food fish for aquaculture diversification in India.Furthermore,the species poses a threat due to habitat degradation and other anthropogenic factors,and has been categorised as“near threatened”,therefore,its culture promotion is warranted.To establish a successful breeding programme,a precise understanding of the life history,and biology(reproductive/feeding)of the fish will assist hatchery managers and researchers.Studies in these areas have been undertaken by several groups over the years,but without much coherence,the data are still fragmented.Few attempts on the culture attributes of this catfish have been performed under both mono-and polyculture systems to bring about parallel promotion through aquaculture in a larger part of the subcontinent.Highlighting this,we have tried to analyse and present a consolidated account of the morphological characteristics,feeding habits,reproductive biology,early developmental ontogeny,and culture potentials of O.bimaculatus in India.This review was also prompted by the paucity of information on the cultural aspects of the species.Additionally,based on the reported studies,future directions and perspectives of the culture promotion of the species are proffered to ensure future research initiatives.

Influence of an Intercultural Factor on the Formation of Sociocultural Capital of a Polyethnic City

The ideas of managing cultural diversity in the modern world are embodied primarily in the concepts of multiculturalism and interculturalism.Multiculturalism can be defined as ideology,politics and social discourse,which recognizes the legitimacy and value of cultural pluralism,the significance of the diversity of cultural forms.In its turn,this allows to form a single sociocultural space based on the tolerant coexistence of traditional ethnic or national cultures.Interculturalism is based on the dialogical paradigm of coexistence of different cultures:recognition of the heterogeneous nature of cultures,acceptance of the thesis of unity in diversity,identifying cultural diversity as a counterweight to assimilation.On the one hand,universal values create the platform of intercultural interaction within the framework of interculturalism,while on the other hand,there are civic culture and responsibility of ethnic groups for their society.Interculturalism is described as a life resource of a modern multiethnic city,a sociocultural capital that can multiply.Multiculturalism is aimed at preserving minority cultures that causes the conservation of the situation,and interculturalism provides an active and positive dialogue of different cultures with the aim of mutual enrichment.The sociological survey was held in the polycultural Ukrainian city of Melitopol,which has been applying policies and practices of interculturality since 2008.The aim is to analyse the interrelation of inter-culturality and sociocultural capital.The results indicate that ethnic communities are sufficiently integrated in public space and they are positively perceived by the city community.Therefore,interculturality is a significant resource of sociocultural capital community.Therefore,interculturality is a significant resource of sociocultural capital accumulation which can be converted in political capital and it can consolidate a city community.