Pen Culture Research Articles

The interaction of feeding regime and dietary specification on growth and nutrient utilisation in Yellowtail Kingfish Seriola lalandi

Feeding regimes on fish farms are often disrupted for logistical reasons or adverse environmental conditions. Issues such as these are commonplace with respect to the sea pen culture of Yellowtail Kingfish Seriola lalandi (YTK) in Australia. These disruptions represent periods of feed restriction which lead to reduced productivity. However, production losses may be ameliorated using different feeding strategies or the use of nutrient dense aquafeeds. To examine the potential of these options we conducted an eight-week experiment with sub-adult YTK (stocking weight ~ 0.80 kg) investigating three feeding regimes crossed with two dietary specifications. The feeding regimes were selected following industry consultation; feeding once daily 7 days per week (control), once daily Monday to Friday (economic) or once daily on randomly selected days of the week (random). Regardless of regime all feed was offered to apparent satiation. A standard specification (Std-Spec; 386 g DP kg−1, 15.1 MJ DE kg−1) and high specification diet (High-Spec; 460 g DP kg−1 and 19.2 MJ DE kg−1) were formulated using a similar suite of ingredients. Each of the 6 treatment combinations was fed to three replicate tanks of fish and results were examined using two-way ANOVA. There was a general absence of interaction between the main effects for most production indices. Specific growth rate (SGR) and relative feed intake (RFI) were significantly better in YTK fed 7 days per week than in YTK fed under more restricted regimes, but feeding regime did not affect FCR. The SGR, FCR and condition factor of YTK were significantly better when fed the High-Spec diet than in YTK fed the Std-Spec diet. The RFI of fish fed under restricted regimes was significantly lower than YTK fed 7 days per week, irrespective of diet specification, indicating YTK were not capable of hyperphagia. However, the RFI of YTK fed the Std-Spec diet was significantly higher than YTK fed the High-Spec diet, confirming nutrient or energy density was likely controlling feed intake. Examination of data on digestible protein, fat and energy intake indicated YTK were eating primarily to satisfy their protein requirement and sub-optimal energy intake was indirectly limiting growth. Our results demonstrate YTK have a limited capacity to increase their feed intake as a means of overcoming moderate feed restriction in order to meet nutrient and energy demands. We recommend feeding YTK of this size a high specification diet to apparent satiation once per day 7 days a week in order to maximize their growth, feed efficiency and physical condition.

Growth Performance and Condition Factor of Juvenile Milkfish (<i>Chanos chanos</i>) Cultured in a Marine Pen in Relation to Body Size and Temperature

The growth performance and condition factor (CF) of milkfish (Chanos chanos) in relation to body size and temperature were investigated in a shallow marine pen culture system in coastal waters of the Philippines. Three common models were tested to determine the best-fit model for the growth of milkfish, and the logistic model was found to be best for both weight-based and length-based growth. Daily specific growth rate in weight (DSGRw) and length (DSGRL) were positively correlated with water temperature, while both DSGRw and DSGRL were correlated negatively with the size of the fish, which supported the fit of the growth model. CF of milkfish exhibited a positive correlation with the feed conversion ratio and significant seasonal variations. The ratio was lower in the fast growth season (dry season) than in the slow growth season (rainy season). By integrating these controversial findings, we were able to posit that low temperature and inefficient feeding makes ‘fat’ fish and vice versa. This may be explained by changes in proximate body composition (e.g., protein and water content) and the change in metabolic rate brought about by different water temperatures.

Multi-criteria based geospatial assessment to utilize brackishwater resources to enhance fish production

The growing demand for protein food and stagnating capture fisheries production is forcing researchers to explore alternative water resources and technologies to increase fish production. The aquaculture site suitability assessment in water bodies would ensure that the selected waterbody will provide a conducive growing environment for fishes without affecting the prevailing environmental ecosystem and the associated activities. Our study assessed the suitability of sites for cage aquaculture in the tropical estuarine ecosystem (Muttukadu-near Chennai, India) using the analytical hierarchy process based multi-criteria decision support spatial analysis. Consequently, 17 functions influencing cage culture were identified and categorized into water quality (pH, temperature, salinity, biological oxygen demand, dissolved oxygen, total ammonia nitrogen, nitrate, nitrite, phosphate, and Chlorophyll), environmental (water depth, water current flow, turbidity and distance to mouth bar) and infrastructure (distance to the seed source, transport and market). The measured variables were interpolated through inverse distance weighted spatial analysis and reclassified to the most suitable and unsuitable extent. The analytical hierarchical process (AHP) based pairwise comparison matrix was used to derive the weightage for each criterion, based on its relative importance. The uncertainty analysis using Monte Carlo simulation was carried out to address the probabilistic variations in AHP judgments. The weighted linear approach has been used to integrate all parameters to generate the output map, that indicates most suitable (5.9%) and suitable (8.1%) area available for cage and pen culture practices. Though the water quality parameters were almost suitable for aquaculture, the depth of water was the major influencing parameter in the estuary, which varied from 0.12 to 3.08 m during the lowest tide. Proper management of the mouth of the river sand bar, ensuring smooth water exchange between sea and estuary, would aid in maintaining the water suitability throughout the year. The present study is the first report indicating as to how geospatial planning in water bodies could help support local communities and the government to make use of the hitherto unusable brackishwater resources as a supportive livelihood option in developing countries.

Evaluation of Indoor and Outdoor Aquaculture Systems as Alternatives to Harvesting Hemolymph From Random Wild Capture of Horseshoe Crabs

This study evaluated two approaches to the aquaculture of L. polyphemus with the ultimate goal of harvesting LAL at an industrial scale. To monitor HSCs, a combination of physical, biochemical and cellular components were examined for HSC cohorts in an indoor recirculating aquaculture system (RAS) and an outdoor on-bottom pen culture system (PCS) over a 6-month period. The metrics included body weight, hemocyanin (Hc) concentration, amebocyte density, and LAL reactivity. In addition, a simulated biomedical bleeding event (extracting 30% of the total hemolymph volume) was performed to assess physiochemical properties of the hemolymph and amebocytes after a one-week recovery period. Overall, the HSCs fared better in the RAS compared to the PCS, with higher rebound kinetics with respect to Hc concentrations, amebocyte density, LAL reactivity, and with 100% survival in the RAS cohort. Further, hemolymph reinfusion (after amebocyte removal) was shown to improve HSC recovery time. In summary, outcomes of this research show that a RAS, coupled with adequate nutrition and care can provide HSCs with a suitable environment for sustainable hemolymph extraction and year-round LAL production.

Marginal damage cost functions for particulate organic carbon loading from open-net pen salmon farms in British Columbia, Canada

Increasing production of salmon open-net pen culture has raised concerns about the negative impact of this aquaculture technology on the marine environment. In British Columbia (BC), Canada, benthic deposition of organic nutrients (faeces and waste feed) is identified as a potential source of localized environmental degradation from salmon farming. In this paper, we develop a marginal damage cost function to provide a quantitative monetary measure for potential environmental impacts of simulated salmon farms, representative of typical BC net pen sites. The development of the functions is done by integrating the outputs of a discrete choice experiment (DCE) with the results of an organic deposition model (NewDEPOMOD). The resulting relationships can be used to find efficient policies and sustainable operation strategies that balance salmon production with the external cost to the marine environment.

Cage culture system principles and practices in India: A review

Cage culture system is one of the emerging techniques of Aquacultural engineering discipline employed for commercial culturing of aquatic species especially fishes in different aquatic environment. Natural resources such as land and fresh water are scarce resources throughout the world. Population burden is increasing day by day especially in developing countries such as China, India and African Countries thus demands for protein rich food sources are increasing. This increase in demand for protein rich food can be fulfilled by using culturing of fishes with some aquaculture techniques such as cage culture and pen culture. The objective of this paper is to try to review the different aspects of cage culture such as its principles, construction, different types and operation in different developing countries of the world especially India, which provides an alternative to land resources and utilized our vast water resources which are present in forms of different ocean, seas, rivers and lakes. India is having different aquatic environment such as freshwater, brackish water and marine water.

Pen Culture Detection Using Filter Tensor Analysis with Multi-Temporal Landsat Imagery

Aquaculture plays an important role in China’s total fisheries production nowadays, and it leads to a few problems, for example water quality degradation, which has damaging effect on the sustainable development of environment. Among the many forms of aquaculture that deteriorate the water quality, disorderly pen culture is especially severe. Pen culture began very early in Yangchenghu Lake and Taihu Lake in China and part of the pen culture still exists. Thus, it is of great significance to evaluate the distribution and area of the pen culture in the two lakes. However, the traditional method for pen culture detection is based on the factual measurement, which is labor and time consuming. At present, with the development of remote sensing technologies, some target detection algorithms for multi/hyper-spectral data have been used in the pen culture detection, but most of them are intended for the single-temporal remote sensing data. Recently, a target detection algorithm called filter tensor analysis (FTA), which is specially designed for multi-temporal remote sensing data, has been reported and has achieved better detection results compared to the traditional single-temporal methods in many cases. This paper mainly aims to investigate the pen culture in Yangchenghu Lake and Taihu Lake with FTA implemented on the multi-temporal Landsat imagery, by determining the optimal time phases combination of the Landsat data in advance. Furthermore, the suitability and superiority of FTA over Constrained Energy Minimization (CEM) in the process of pen culture detection were tested. It was observed in the experiments on the data of those two lakes that FTA can detect the pen culture much more accurately than CEM with Landsat data of selected bands and of limited number of time phases.

Genomic and Proteomic Characterization of Bacteriophage BH1 Spontaneously Released from Probiotic Lactobacillus rhamnosus Pen.

Lactobacillus rhamnosus Pen is a human endogenous strain used for the production of probiotic formula, which is effective in the prevention of antibiotic-associated diarrhoea. Our study showed that this probiotic strain releases bacteriophage BH1 without the addition of any inducing agent. Our research revealed that phage BH1 has a circular genome with a length of 40721 nt and a GC content of 44.8%. The genome of phage BH1 possesses 57 open reading frames which could be divided into functional modules associated with DNA packaging, morphogenesis, lysis, integration, genetic switch, and replication. In spite of similarity in morphology and genomic organization, comparative analysis revealed substantial genetic diversity and mosaic genomic architecture among phages described for the Lactobacillus casei group. Additionally, qPCR and ddPCR analysis confirmed earlier microscopic observations indicating that L. rhamnosus Pen liberates bacteriophage particles during growth. This occurs spontaneously, and is not a result of external inducing factors. For samples collected after 4 and 24 h of L. rhamnosus Pen culture, the number of attB and attP copies increased 2.5 and 12 times, respectively. This phenomenon, by introducing resistance to other phages or enhancing the biofilm-forming capabilities, may increase the survivability of microorganisms in their natural ecological niche. Conversely, spontaneous phage induction may be an important virulence factor for bacteria, posing a potential threat for the human host.

The Effect Of Polyculture White Shrimp Vannamei And Seaweed On Different Plant Distance On Growth, Survival And Phytoplankton Abundance

The aim of the study was the effect of white shrimp polyculture, and seaweed in an effort to increase the growth and survival of white shrimp and seaweed and control the abundance of phytoplankton. The research method was a completely randomized design with 4 treatments and 3 replications namely T1 (10V + 10 cm RL): given 10 seeds / m 2 white shrimp and seaweed 10 cm spacing, T2 (10V + 20RL) = 10 seed / m 2 white shrimp and seaweed planting distance of 20 cm, T3 (10V + 30RL) = 10 seed / m 2 white shrimp and seaweed distance 30 cm, T4 (10V + 40RL) = given 10 seed / m 2 white shrimp Vannamei and seaweed plant distance 40 cm), and observed abundance of plankton used sample collected (April-August 2018) from site (T1),(T2),(T3) and (T4) of this penculture pond. The weight of Gracillaria sp 150 g / to treatment with the long line system was placed around the plot of waring area of 1 m 2 in the pen culture pond area of 300 m 2 . Data collection included: absolute weight growth, survival, FCR, and water quality data (temperature, salinity, pH, O 2 , NO 2 , NH 3 ). Data were analyzed for variance and to find out the middle values between treatments, Tukey Test analysis was performed. The results showed that the presence of white shrimp and seaweed polyculture engineering at different plant distance had a significant effect (P <0.05), on growth and survival and effected community structure and abundance of phytoplankton. The highest absolute weight growth in white shrimp ( L. vannamei (g) on T4 (27.53 ± 0.04 g), white shrimp survival (90.25%), white shrimp of FCR (FCR = 1.19 ± 0.05 b ), and also on seaweed Gracillaria verocosa on T4 has the highest growth of absolute weight of seaweed ( G. verocosa ) (g), namely 2905.05 ± 7.5 b , survival of T4 seaweed (93.33 ± 0.25% and abundance of phytoplankton

Mapping the potential areas for enclosure fish culture in tropical reservoirs: geo-spatial solutions for sustainable aquaculture expansion

Planning aquaculture and fisheries activities in a reservoir requires knowledge of dynamics of water spread. We studied water spread dynamics of three reservoirs in the Godavari river basin, India using multi-temporal satellite imagery for the period 1990–2018 and developed a framework for mapping the spatial extent of water spread area (WSA) having potential for enclosure fish culture. The study showed that WSA of Nizamsagar reservoir in pre-monsoon season has declined from 108.11 to 99.34 km2 from phase I (1990–2006) to phase II (2007–2018), respectively and a similar trend was seen in Pocharam and Nallavagu reservoirs. For post monsoon seasons of the same time period, an increase in WSA was seen in Nizamsagar (133.75–144.14 km2) and Pocharam reservoirs (14.15-14.67 km2). Based on frequency of water presence during 2007–2018, WSA with potential for cage and pen culture was determined in Nizamsagar (31.04 km2) and Pocharam (2.87 km2) reservoirs. The study showed that both the reservoirs can accommodate maximum allowed number of cages (5000 and 500 cages respectively). We provide a decision matrix for location-specific selection of suitable culture methods and candidate species, which would aid in optimal utilization of the hitherto under-utilized reservoirs, especially in in situ data poor conditions. This study can be scaled up in the entire country with the help of academia/industry to prioritize reservoirs with potential for enclosure fish culture and plan appropriate interventions for reducing their yield gap.

Utilization of Ex Tin Mine Lake For Aquaculture: Case Study Of Muntok Sub District, West Bangka Regency

Tin mining has left hundreds of ex-mine lake in Muntok Subdistrict, West Bangka Regency, which is both problems and potential to be exploited. Empowerment of the lake for freshwater fish farming can provide alternative livelihood opportunities besides tin mining. The study of the use of the lakes for fish farming aims to determine the purpose of fish farming with its problems and potential. The study was conducted in June - July 2018 with a descriptive qualitative method through a process of interviews and observations during the implementation of the task of fisheries instructor. The object is on three groups who use the lake for fish farming. The lake can be used productively for catfish and catfish culture utilizing the system of the pen culture. The obstacle of using the lake for fish culture is the potential for bioaccumulation of heavy metals, the difficulty of implementing water quality management, and lower productivity compared to artificial ponds. Under cultivation is recommended to choose Clarias commodities in consideration of consumer safety against bioaccumulation of heavy metals.

The Environmental Impact of Sturgeon Pen Culture on Diversity and Spatial Distribution Patterns of the Benthic Macro Fauna Communities in Gorgan Bay

Community structure and biodiversity of benthic macro fauna in around pen culture of Sturgeon fish in Gorgan Bay were studied for period of one year from August 2015 to July 2016. Seasonal samplings were carried out at 5 stations in 3 transects. In addition, depth (D), water temperature (Toc), dissolved oxygen (DO); pH, total dissolved solid (TDS), biological oxygen demand (BOD5), chemical oxygen demand (COD), phosphorus (PO4-3), nitrite (NO2-) and total ammonia (NH3+) were measured in each station. Results of season variations of Physico &amp;ndash; chemical factors of water showed that, there were no significant differences between PO4-3 (p&amp;gt;0.05). However, there were significant differences between BOD5, COD, NO2-, NH3+ and TDS (p&amp;lt;0.05). Totally, 11 genus&amp;#39;s and 10 families belong to 3 phyla as Mollusks, Arthropods and Annelids were identified. The results showed, there were the maximum abundance percent belong to Hydrobiidae and Cochliopidae with 33.83% and 26.25% and the minimum abundance percent belong to Gammaridae with 0.05% respectively. However, the maximum abundance belongs to Pyrgohydrobia sp., from Hydrobiidae with 3410 n/m2. The results showed, there were the maximum and minimum abundance percent in autumn and spring with 1.07 and 0.88 % respectively. The results of distance-based redundancy analysis (db.-RDA) revealed that environmental factors such as depth, DO and TDS are all important in determining the distribution of macro benthic species in Gorgan Gulf. However, there were significant differences between abundance, species number (S), diversity (as Shannon&amp;ndash;Wiener&amp;rsquo;s, H&amp;acute;), species richness (as Margalef&amp;rsquo;s, D), and evenness (as Pielou&amp;rsquo;s, J) (p&amp;lt;0.05). There were the most diversity species in 2 and 5 stations.

Impacts of pen culture on alpha and beta diversity of fish communities in a large floodplain lake along the Yangtze River

Pen culture is a cumulative factor leading to water quality degradation, competition intensification, habitat alteration and fragmentation. Despite the unprecedented expansion of pen culture areas in Chinese lakes due to the increasing demands on fishery products, little is known about the potential impacts of pen culture on fish communities. Here, we addressed this issue by quantifying changes in alpha and beta diversity with its turnover and nestedness-resultant components between pen culture areas (PA) and non-pen culture areas (NPA) in a large floodplain lake lying on the northern shore of the Yangtze River. Fish communities were sampled seasonally from January 2016 to December 2016 in 16 representative sites (PA, 8; NPA, 8) of Lake Huayanghe using fyke nets. In comparing with fish communities in NPA, we demonstrated an overall loss of fish species and a significant reduction in alpha diversity (richness) in PA, which were probably due to habitat alteration and fragmentation triggered by pen culture. We reported a significantly lower overall beta diversity with its turnover component and a significantly higher nestedness-resultant component in PA. The homogenized and nested trend for fish communities in PA was triggered by the synthesized effects of abiotic and biotic factors. Net pens caused habitat fragmentation and blocked the offset effects by supplementary fish species in nearby habitats, thus resulting in a significantly lower turnover and higher nestedness-resultant component in PA. The introduction of the same cultured fish species and the decrease of the wild native fish species made the fish communities in PA become more homogenized and nested. Pen culture had resulted in a significant decline in alpha diversity and a designed homogenization for fish communities in the lake. Our study highlighted the urgent need for systematic assessment of cultured fish and effective control of pen culture areas to avoid the future fish homogenization and species loss in Chinese lakes.

The Effectiveness of pen‒culture construction for cultivation of sea cucumber

&lt;p align="center"&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Sea cucumber &lt;em&gt;Holothuria &lt;/em&gt;sp. is a marine biota that has economic value. The rearing activity of sea cucumbers is still limited to the have bay or strait areas with relatively calm coastal. This research aimed to determine the effectiveness of two types of pen‒culture system for sea cucumber rearing to the influence of ocean waves and currents. This research was done from February to July 2017 in the coastal of Rat village, Southeast Maluku Regency. The two of cultivated containers tested were a conventional pen‒culture (treatment A) and engineered pen‒culture (treatment B). A total of 30 individuals sea cucumber seeds sized 4‒6 cm were released at each pen‒culture. Survival rate and water quality were also calculated as supporting data. Observation of endurance and clearance of pen‒culture was done every two weeks. The result of visual observation showed that conventional pen‒culture treatment A was more quickly damaged and it was more damaged compared to engineered pen-culture treatment B.Through t‒test we got T &lt;sub&gt;count&lt;/sub&gt; (1.065) &amp;lt; T&lt;sub&gt;table&lt;/sub&gt; (6.313) for survival and T &lt;sub&gt;count&lt;/sub&gt; (0.084) &amp;lt; T&lt;sub&gt;table&lt;/sub&gt; (1.782) for growth. The result means that treatment A and treatment B have the same effect onsurvival rate and growth of sea cucumber. The results showed that treatment B was better applied to more open waters than treatment A.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;Keyword: endurance, pen‒culture, sea cucumber, survival, growth&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p align="center"&gt;&lt;strong&gt;Abstrak&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Teripang &lt;em&gt;Holothuria &lt;/em&gt;sp. merupakan biota laut yang memiliki nilai ekonomis. Kegiatan budidaya teripang masih terbatas pada daerah‒daerah yang berteluk atau berselat dengan perairan yang relatif tenang. Penelitian ini bertujuan untuk membandingkan efektivitas dua sistem budidaya teripang dalam kurungan tancap terhadap pengaruh gelombang laut dan arus. Penelitian ini berlangsung dari bulan Februari hingga Juni 2017 di perairan Desa Rat, Kabupaten Maluku Tenggara. Dua tipe wadah budidaya yang diujicobakan adalah kurungan tancap konvensional (perlakuan A) dan kurungan tancap yang direkayasa (perlakuan B). Pada setiap kurungan tancap, dimasukkan teripang pasir berukuran 4‒6 cm sebanyak 30 ekor. Sebagai data pendukung, dihitung persentase kelangsungan hidup dan pengukuran kualitas air. Pengamatan ketahanan dan kebersihan kurungan tancap dilakukan setiap dua minggu sekali. Hasil pengamatan visual diketahui bahwa kurungan tancap perlakuan A lebih cepat rusak dan mengalami kerusakan yang lebih besar dibandingkan perlakuan B. Melalui uji-tdiperoleh hasil T&lt;sub&gt;hitung&lt;/sub&gt; (1,065) &amp;lt; T&lt;sub&gt;tabel&lt;/sub&gt; (6,313) untuk kelangsungan hidup, dan T&lt;sub&gt;hitung &lt;/sub&gt;(0,084) &amp;lt; T &lt;sub&gt;tabel&lt;/sub&gt; (1,782) untuk pertumbuhan. Hasil uji‒t bermakna bahwa perlakuan A dan perlakuan B memiliki pengaruh yang sama terhadap kelangsungan hidup dan pertumbuhan teripang. Hasil pengamatan menunjukkan bahwa perlakuan B lebih baik diaplikasikan pada perairan yang lebih terbuka dibandingkan perlakuan A.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;Kata kunci: ketahanan, kurungan tancap, teripang, kelangsungan hidup, pertumbuhan&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Effect of Stocking Density on Survival, Growth and Production of Mud Crab Juvenile by Pen Culture System of Bangladesh

Effect of Stocking Density on Survival, Growth and Production of Mud Crab Juvenile by Pen Culture System of Bangladesh

Enhancing fish productivity through pen culture: a case study in Sareni wetland of Uttar Pradesh

Pen culture for in situ raising of stocking material was conducted in Sareni Jheel, located in the Rae Bareli District of Uttar Pradesh. Sareni Jheel, being rich in organic carbon (4.5%) and nutrients, higher values of silt (29%) and clay (15%) were recorded. Rich oxygen levels, alkaline pH, high organic matter, moderate to high chemical parameters suggested moderately productive nature of this wetland. Pen with high-density polyethylene (HDPE) net was installed in an area of 0.1378 ha and stocked with advanced fry of the Indian major carps, rohu Labeo rohita and catla Catla catla in the ratio of 1:1 @ 25 nos. m-2. No significant changes in water quality parameters were noticed within and outside the installed pen. Mean weight at stocking of rohu and catla was 2.88±1.41 g and 2.1±1.16 g, which increased to 57.2±13.84 g and 67.38±25.79 g respectively, in 120 days. The average feed conversion ratio (FCR) recorded was 1.08 with overall survivability of 69.52% in rohu and 74.74% in catla. Benefit-cost ratio and return on investment were calculated as 1.69 and 0.69, respectively. Intervention through pen culture resulted in the increase in fish productivity of Sareni Jheel from 310 to 833 kg ha-1.

Salmonid Jumping and Playing: Potential Cultural and Welfare Implications.

Simple SummarySalmonids jump from the water in nature and in confinement. These behaviors are economically important and relevant to fish welfare. In net pen culture, the need to control parasitic sea lice has motivated studies of salmonid jumping behavior. Some instances of jumping in salmon may be a form of play. Indigenous and institutional science, cultural wisdom, and direct observation can aid the understanding of these behaviors.Salmonids of several species and other fishes can jump into the air from the water. This behavior has been used in net pen culture applications to control parasitic sea lice. The reasons that salmonids jump remain a topic for speculation. Research on these behaviors has focused on Atlantic salmon in net pen culture in Northwest Europe. Jumping in salmonids is a heterogeneous behavioral category with diverse functional outcomes. Additional research is needed from broad perspectives spanning indigenous and institutional science, cultural wisdom, and ethological direct observation. In theory and in practice, it is interesting that some salmonid jumping behavior may be a form of play.

Effect of Different Stocking Densities on Growth and Survival Rates of Sea Cucumber Holothuria scabra Seedlings

As sea cucumber, Holothuria scabra is one of the fishery commodities which have high economic value, this species now is under overexploited. Sea cucumber aquaculture should be developed urgently. This research was conducted to evaluate the effects of stocking densities on the growth and survival rates of sea cucumber. This research was carried out by using pen culture with 5 – 9 cm in length or 30 – 50 g of seedlings. The sea cucumber was reared with stocking densities of 15 (treatment A), 20 (treatment B) and 25 individual/m 2 (treatment C) in triplicates. The observation of growth and survival rates were done every two week. The water quality was measured every three day. The result indicated that the growth and survival rates was higher in treatment A than treatments B and C.

Mud Crab (Scylla serrata) Fattening in Pen Culture System: Changes of Proximate Composition due to Fattening

The study was conducted to know the crab fattening in pen system and to evaluate the changes of proximate composition of mud crab due to fattening. After fattening, proximate composition was analyzed to assess the changes of nutritional value. The average survival rates of male and female crab were 64.722 ± 1.204% and 65.889 ± 0.701% respectively. The mean specific growth rate (SGR) was 1.245 ± 0.334% (male) and 0.976 ± 0.152% (female). The average value of FCR was 5.833 ± 0.119 and production rate was 0.4116 ± 0.095 kg/m2. Due to fattening, the moisture content of mud crab was decreased from 77.747 ± 0.705 to 75.551 ± 1.537% in male and from 75.030 ± 0.370 to 74.332 ± 0.202% in female. The mean crude protein content of the male mud crab (Scylla serrata) with shell was decreased but in case of female it was increased. The mean crude lipid content of mud crab was increased from 0.420 ± 0.110 % to 1.113 ± 0.102% and 1.093 ± 0.110 to 2.208 ± 0.204% respectively both of male and female. During fattening period the mean ash content was also increased in male and female. In addition the study showed that the mean crude fibre content also increased from 1.162 ± 0.089 to 1.613 ± 0.580% and 1.556 ± 0.367 to 1.884 ± 0.020% respectively in male and female. Furthermore nitrogen free extract content increased from 0.838 ± 0.064 to 0.982 ± 0.238% in male and from 1.251 ± 0.421 to 1.682 ± 0.640% in female. It was observed that all the nutritional compositions were changed due to fattening.

Comparative Study of Growth and Carrageenan Content of Kappaphycus alvarezii (Doty) Doty in Pen Culture and Raft Culture in Palk Bay Waters of Ramanthapuram District, Southeast Coast of India

The cultivation of Kappaphycus alvarezii, a kappa carrageenan yielding red seaweed has been going on in different locations of the world since 1970. This seaweed has been introduced under field cultivation in more than 20 tropical countries. Philippines and Indonesia contribute to 92% of the entire global harvest of 183,000 ton dry and the other countries include Malaysia, China and Salmon Islands. In India, this alga has been introduced in the second half of 1995 and the commercial cultivation has picked up from 2006. In order to evolve an economically feasible method for commercial cultivation, this study was done for a period of one year from April 2010 to March 2011 in sub-tropical waters on Palk Bay side of Bay of Bengal of Ramanthapuram (Umiyalpuram, Mandapam) district on southeast coast of India. The experiments were carried out by two methods, 1) PEN culture i.e; cultivation in monolines enclosed with net and 2) raft method with net bottom. The minimum crop yields of 241.10±9.52 and 228.90±14.89 kg FW raft-1 were obtained in May 2010 in PEN culture and raft respectively with respective maximum ones of 325.30±11.26 and 293.10±9.83 kg FW raft-1 in October 2010. Similarly the minimum daily growth rates (DGRs) of 3.09±0.09 and 2.97±0.09 % were found in May 2010 in PEN culture and raft culture respectively with respective maximum daily growth rates (DGRs) of 3.76±0.08 % and 3.52±0.07% in October 2010. Environmental parameters like seawater temperature, salinity, nitrate and phosphate were recorded and they were found to influence the growth of the seaweed. The maximum carrageenan (SRC) content of 36.76±0.74% and 34.09±0.97% of dry weight was found in August 2010 for PEN culture and raft culture respectively whereas the minimum ones of 31.92±1.28% in December 2010 in Pen culture and 30.04±0.12% in October 2010 in raft culture. The income with mean annual crop yields would be Rs. 18,257/- and Rs. 16,063/- per month/person in PEN culture and raft respectively during the loan period and with the respective ones of Rs. 19,257/- and Rs. 18,063/- per month/ person after the loan period (after three years). In view of this, PEN culture was recommended for commercial cultivation rather than raft one in the shallow waters and this was arrived at considering the infra cost, replacement of the infra, cultivation operation, carrageenan yield and net income. Keywords: Seaweed farming, Daily growth rate, Kappaphycus, Carrageenan, Crop yield