First record of angry worm eel Skythrenchelys zabra (Anguilliformes: Ophichthidae) from the east coast of India

413-415Skythrenchelys zabra (Castle and McCosker, 1999) a species belonging to the family Ophichthidae is reported for the first time from the east coast of India on the basis of 11 specimens collected from various fishing harbours along the West Bengal, Odisha and Andhra Pradesh coasts. The species was first described from south-west coast of India in the Arabian Sea. The present report extends the range of distribution of the species to the Bay of Bengal along the east coast of India

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Not AvailableStudies on waste production and feeding management of Penaeus monodon in semi-intensive culture system were carried out for four successive crops at a commercial farm (M/S Suryo Udyog Ltd.) at Chandipur Coast of Orissa, India, at six different stocking densities. The prescribed feeding programme of C.P. Group, Thailand (NOVO-shrimp feed) were adopted and standardized during first two crops and the standardized feeding scheme was evaluated in the last two crops. Influence of standardized feeding programme on average feed conversion ratio (FCR) of P. monodon was highly significant (p < 0.001) against that of manufacturer’s (NOVO-feed) prescribed feeding programme. A feeding frequency of more than four times a day showed no improvement in growth rate and there was no change in diurnal feeding habit probably due to the fact that, in scientific farming, aquatic environment is artificially controlled. It was also observed that, as the age and weight of shrimp increases, feed % decreases from 8.8 to 1.9% and lift net (LN)% increases from 2.4 to 4.3% for 1–40 g mean body weight of P. monodon respectively. The higher the stocking density, the higher was the FCR and sedimentation rate. In the present experiment, the sedimentation rate was estimated to be 49.5 m3 (dry volume)/1000.0 kg of shrimp biomass. The average quantity of waste matter production was only 571.4 kg of organic matter, 10.21 kg of nitrogen and 0.527 kg of phosphorus at an average FCR of 1.437 and stocking density of 22.5 pcs m-2 during the four crop experimental period.Not Availabl

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Not AvailableThis study was carried out to study the impact of phased harvesting on the population structure, feed intake pattern and growth performance of Macrobrachium rosenbergii in polyculture with carps in a deepwater rice–fish system. There were two experimental conditions—rice–fish culture with phased harvesting (T1) and rice–fish culture without phased harvesting (T2)— and a control, which consisted of rice monoculture without fish (T3). In the T1 trial, 61% of the population had a mean body weight (MBW) 80 g in the T1 trial, while none of the population reached a MBW > 80 g in the T2 trial. The removal of fast-growing individuals in T1 improved the prospects of other smaller individuals to achieve their individual growth potential. This step also disrupted the continuation of the socially induced differential growth rates, resulting in a wide variation in size within the population over time. The matrix of dietary overlap(s) of cultured species revealed that the degree of food preference was more similar between Cyprinus carpio and M. rosenbergii (0.9), while it overlapped poorly between Catla catla and M. rosenbergii (0.42). This high similarity index between bottom dwellers is evidence of the strong possibility that these bottom dweller compete for food. Natural and supplemental feed together with phased harvesting boosted the production of freshwater prawns (550 kg/ha) in the T1 trial, while a 11.3% reduction in production was recorded in the T2 trial.Not Availabl

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Not AvailableThe degraded state of the fragile ecosystem of Chilika Lake, located on the east coast of India, was undergoing restoration through an effective hydrological intervention during the year 2000. Studies on the lake’s hydrobiology and fisheries for the period of 7 years before and 7 years after the hydrological intervention indicated a rapid recovery of the lake fishery immediately after opening of the new lake mouth, with a sixfold increase in the average annual fish landings. During 2000–2001 to 2006–2007, the average fisheries output (11 051.3 t), catch per unit effort (6.2 kg boat)1 day (1), the economic valuation of the average annual catch (637 million rupees) and productivity (11.97 t km) (2) exhibited dramatic increases of 498%, 464%, 1177% and 498.5%, respectively, compared with the 7-year pre-intervention data. Multivariate statistical analysis inferred that most of the lake’s environmental variables are strongly associated with salinity factor, which seems to have governed the lake ecology. The salinity dynamics of the lake are governed by both freshwater inflows and seawater ingress through the new artificial lake mouth. Correlation analysis indicated that salinity was positively correlated with prawn catch (R2 = 0.542; d.f. = 25; P < 0.01), crab catch (R2 = 0.628; d.f. = 25; P < 0.001) and fish catch (R2 = 0.476; d.f. = 25, P < 0.05). The average increase in the salinity regime (43.8%) for the lake during the post-hydrological intervention period, compared with the pre-hydrological intervention period, appears to have positively impacted the fish, prawn and mud crab catches. A gradual decrease in total fisheries output since 2005–2006, however, was attributed mainly to a continuing increase in destructive fishing practices in the absence of any conservation and regulatory measures for fishing, and large-scale collection of shrimp juveniles from the outer channel for shrimp aquaculture. Thus, carefully planned conservation and regulation measures must be ensured, with active participation of local communities during this early phase of lake restoration. In the absence of such measures, the present scenario of fisheries enhancement might not be sustained over the long term.Not Availabl

Cyclic feed restriction on growth compensation of <em>Penaeus monodon </em> (Fabricius): science meets practice

2008-2016Effects of cyclic feed restriction on compensatory growth (CG) performance of Penaeus monodon, sediment loading and water productivity in a grow-out production system were examined in 119 days of culture duration. Among different feed management protocols (T1: Regular feeding, 4-times a day; T2: 2-weeks feeding followed by 1-week no feed; T3- 4-weeks feeding followed by 1-week no feed), overall crop performance was in the similar line in both T1 and T2 except significantly (P2. This was probably due to the prevailing optimal salinity (19.1 ± 1.8 psu), DO (6.1±0.7 ppm) and water pH (7.54±0.13). Among T2 and T3, there was no significant (P3(CGI, 98-105%) and partial CG in T2 (89-96%).Shrimp on the cyclic feed restriction may have better used pond resources by increasing the consumption of natural productivity that increased the feed efficiency (71.6-73.5)

Juvenile abundance and post-larval incursion of mud crabs (<i style="mso-bidi-font-style:normal">Scylla </i>spp.) in Chilika lagoon

834-840was carried out on the juvenile abundance and post-larval incursion of two species of Scylla into the lagoon for period of two years from August, 2005-July, 2007.<span style="color:black;mso-bidi-font-weight: bold;mso-bidi-font-style:italic"> Occurrence of juvenile, <span style="color:black;mso-bidi-font-weight: bold">S. serrata<span style="color:black;mso-bidi-font-weight:bold; mso-bidi-font-style:italic"> were throughout the year, while in <span style="color:black; mso-bidi-font-weight:bold">S. tranquebarica<span style="color:black; mso-bidi-font-weight:bold;mso-bidi-font-style:italic">, juveniles were not encountered during December-February. December-May register higher median CPUE values with peak in March for S. serrata. In <span style="color:black;mso-bidi-font-weight: bold">S. tranquebarica<span style="color:black;mso-bidi-font-weight: bold;mso-bidi-font-style:italic">, the peak juvenile abundance period was restricted to June-September with peak in July. The CPUE values for juveniles indicted that the recruitment was intense for S. serrata during post-winter (January-April) and for <i style="mso-bidi-font-style: normal">S. tranquebarica during monsoon (June-September). The crab seeds were available throughout the year which gave a clear evidence for the year round recruitment with the peak during the months of November-March for Scylla species from the Bay of Bengal to the Chilika lagoon. During the study period, the megalopa and first crab instar recruitment per net-hour collection was significantly higher during spring tides than neap tide phase (p&lt; 0.05) and also higher incursion was observed in the night hours than day hours (p&lt; 0.05).<span style="mso-bidi-font-weight:bold;mso-bidi-font-style: italic"> Significantly higher night collections of mud crab juveniles (mixed population of both species) from net box traps (khandas) were obtained during new moon phases (t=3.88; d.f.=11; P&lt; 0.01). </span

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Carapace width and weight relationships, condition factor, relative condition factor and gonado-somatic index (GSI) of mud crabs (<i style="">Scylla spp.</i>) from Chilika Lagoon, India. </smarttagtype></smarttagtype></smarttagtype>

120-127Carapace width (CW)-weight relationship, condition factor (K), relative condition factor (Kn) and gonado-somatic index (GSI) for meaty and post-moulted crabs of both sexes of the two mud crab species, Scylla serrata (Forskal) and S. tranquebarica (Fabricius) co-existing in Chilika lagoon, Orissa, India, were studied during August, 2005 to July, 2007. CW-weight equations and correlation co-efficient (r) obtained for both sexes of meaty and water crabs of the two species were significant (P< 0.05-0.01). Regression slopes (b) were higher for males and fattened crabs in both the species. The K and Kn values recorded in each month for different size groups of both sexes of the two species were higher in male and values were relatively higher in S. tranquebarica than S. serrata. Increase in Kn values beyond 1.0 from 81-91 mm CW in S. serrata and 111-120 mm CW in S. tranquebarica indicated the size at first maturity. Higher monthly values indicated that breeding period was extended from August-November and March-July in S. serrata and S. tranquebarica respectively. Species-specific study aimed at establishing difference in biological characters between two species of Scylla[a′] from same brackishwater habitat. CW-weight relationship may be useful in setting feeding rates for a particular species in aquaculture

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Not AvailableThis study was carried out for three successive years during 1999–2001 to evaluate growth and yield performance of fish, prawn and paddy under rice–fish integration system in rainfed medium land ecosystem. Irrespective of stocking density, faster growth rate was recorded for Catla catla followed by Cyprinus carpio, Cirrhinus mrigala, Labeo rohita and Macrobrachium rosenbergii. C. carpio and C. mrigala performed better growth rate against that of L. rohita probably due to the fact that being bottom dwellers, C. carpio and C. mrigala are more tolerant to fluctuation of oxygen concentration. Productivity of fish and prawn was, however, higher ( p < 0.05) in refuges with 10-cm weir height plots, irrespective of stocking density, while overall yield performance was good at stocking density of 25,000 ha 1. It was observed that, even with supplemental feeding, with increase in stocking density, biomass yield increased up to an optimum and then decreased. An average minimum and maximum yield of 906.6–1282.3 kg ha 1 of fish and prawn has been achieved, which was much higher than the earlier recorded productivity in a season under rice–fish integration system. Highest grain yield was recorded at 15-cm weir height plot (3629 kg ha 1), probably contributed by higher number of panicles per square meter (235.5) and number of filled grains per panicle (121.7). Percentage increase in rice yield under rice–fish integration system was 7.9–8.6% against control, where paddy was cultivated without integration of fish and prawn probably due to better aeration of water, greater tillering effect and additional supply of fertilizer in form of leftover feed and fish excreta. Irrespective of stocking density, the overall rice equivalent yield (REY) of the system was high (4.22–4.55 tons ha 1) at 12.5-cm weir height plots-cum-refuge, without using any pesticide, herbicide, etc.Not Availabl

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Not AvailableThis study was designed to quantify the total water requirement and consumptive water use in carpprawn polyculture system under different water management protocols, using water balance model. Under different water management protocols, treatment-wise estimated total water use, TWU (9104, m3) was 3.7, 4.6 and 3.9, while the computed consumptive water use index, CWUI (m3/kg biomass) was 6.62, 9.31 and 7.08, in T1 (no water exchange), T2 (periodic water exchange) and T3 (regulated water exchange) respectively. Significantly higher yield (P < 0.05) in both T2 and T3 over T1, was probably due to water exchange that improved the rearing environment. Although intensity of water exchange was more in T2, significant variation (P < 0.05) in overall growth and yield was not recorded between T2 and T3. Treatmentwise sediment load ranged between 54.6 and 71.3 m3/t biomasses. Higher sediment load was recorded at lower intensity of water exchange as well as with higher apparent feed conversion ratio. Higher net total water productivity, net consumptive water productivity and OV-CC ratio in T3 infers that regulated water exchange has a distinct edge over the no water exchange protocol. Restricted water use instead of regular/excess water exchange not only improves the production performance and water productivity, but also helps in lessening the operational pumping cost.Not Availabl

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Not AvailableAttempts were made to study the effect of stocking density and water saving approach on water and sediment quality, growth and production performance of shrimp (Litopenaeus vannamei). The experiment was carried outwith three stocking density of post-larvae i.e. 400,000 per ha (T1), 500,000 per ha (T2) and 600,000 per ha (T3).Water exchange was carried out depending on water quality parameters. Water quality suitability index (WQSI) was lower at higher stocking density as was evident in T3 followed by T2 and T1. A very good WQSI (7.5–9.0) was recorded up to 13th, 12th and 9th week of culture in T1,T2 and T3, respectively; which was ascribed to stocking density, smaller shrimp size and less initial feed input. In L. vannamei culture, optimum stocking density of 50 post-larvae per m2 (T2) led to total water use of 3.42 × 104 m3 and water exchange of 0.80 × 104 m3. It was perceived as a way to improve shrimp productivity (10.31 t/ha 120/d), consumptive water use index (1.93 m3/kg biomass), total water footprint (1426 m3/t biomass), net consumptive water productivity (USD1.13/m3) and ratio of output value to the cost of cultivation (1.99). Further, farming systems with low to moderate water exchange as in T2, helped maintain water quality suitable for the shrimp growth, improved water use efficiency (518 g biomass/m3 water), minimized quantity of sediment load (41.7 m3/t biomass) and effluent outputs (0.8 × 104 m3). The knowledge derived from this study could provide the basis to optimize pond rearing efforts in shrimp culture and the water management strategies can be tailored to minimize production costs.Statement of relevance: This paper presents findings and analysis, from a methodologically rigorous investigation and provides insight regarding density-dependent optimum water use, its effect on pond water quality, sedimentation rate, growth performance, water productivity and water footprint. The knowledge derived from this study may be a basis to optimize pond rearing efforts in shrimp culture and the water management strategies can be tailored to prevent wasteful use of water and enhance water use efficiency and water productivity.Not Availabl