NOPR Collection:

Biomass, horizontal zonation and vertical stratification of polychaete fauna in the littoral sediment of Cochin estuarine mangrove habitat, south west coast of India

2009-05-27T16:30:33Z

Title: Biomass, horizontal zonation and vertical stratification of polychaete fauna in the littoral sediment of Cochin estuarine mangrove habitat, south west coast of India Authors: Kumar, R. Sunil Abstract: Biomass distribution, horizontal zonation, relative dominance and vertical distribution of polychaetes were studied. Highest biomass was recorded in the mid tidal region in both study areas. The monthly values varied from 4.43 to 128.28 g.m^-2 at st 1 and 2.57 to 67.31 g.m^-2 at st 2. Multiple regression analysis between biomass and environmental parameters indicate that they could not individually or in combination bring about the spatial and temporal variability in biomass distribution. Moreover, at st 1 edaphic factors appear to be responsible for partial variation in biomass indicating comparatively high F ratio for variance analysis than station 2. ANOVA of species diversity indices values (P<0.5) between the three tidal regions showed a clear horizontal zonation of polychaetes, especially at st 1. A substantial difference in percentage composition of fauna, up to 15 cm depth of mangrove soil, was found in all the three tidal zones studied. This variability in the community structure in the top (0-5 cm) and deeper mangrove sediment (10-15 cm) is pertained to a variety of characteristic features of both upper and deeper sediments. High numerical abundance and coexistence of certain euryhaline species showed significant similarity index (>70%) among polychaete fauna. This similarity and affinity of fauna for a long period evidently indicate the habitat stability that is pertained to the existence of species diversity and abundance. This is related to the prolonged food resource input and profound standing capacity in the littoral mangrove soil, which virtually render in building up a stable community structure of polychaetes. As a result of this, selection of habitat by polychaetes, its survival and subsequent long-term biomass production were occurred. The strong similarity of polychaete fauna between months and biomass productivity can be considered for deriving the productive characteristic of the mangrove habitat, and also for assessing demersal fishery potential. Page(s): 100-107

Biochemical composition of zooplankton from Visakhapatnam harbour waters, east coast of India

2009-06-03T16:30:20Z

Title: Biochemical composition of zooplankton from Visakhapatnam harbour waters, east coast of India Authors: Rao, I. Nageswara; Kumari, R. Ratna Abstract: Proximate composition, zooplankton biomass, protein, lipid, carbohydrate, organic carbon and calorific content of mixed zooplankton in the Visakhapatnam harbour waters were estimated. Biomass varied from 15.2 to 74.0 ml.100 m^-3(=31.05 ±17.7) in the outer harbour and 10 to 64.0 ml.100 m^–3 (=26.30±14.8) in the inner harbour. Copepods, tintinnids, decapods and chaetognaths formed dominant groups of total zooplankton ( > 90%) in the harbour waters throughout the year. Of the biochemical fractions of zooplankton, protein formed the major component, varied from 233.6 to 563 mg.g^-1 (=379.62±107), lipid varied from 61.2 to 181 mg.g^-1 (=103±32.7). Carbohydrate ranged from 65.5 to 127.4 mg.g^-1 (=85.78±16.92), organic carbon varied from 334.9 to 461.2 mg.g^-1 (=380.44±33.6) and calorific values varied from 2.2 to 5.4 (=3.5±.94) k.cal.g^-1. Higher values of these constituents were observed during high saline premonsoon and postmonsoon periods when the population densities of copepods, tintinnids, decapods, chaetognaths were high. Significant positive correlations (P < 0.01) observed between calorific values, protein, lipid indicates to certain extent, that latter act as metabolic reserve of the zooplankton. Based on the results zooplankton do not have extensive lipid storage suggesting that protein in addition to the lipid may serve as metabolic reserve. Relatively higher calorific values were attributed to the dominance of copepods in the zooplankton population throughout the year. Page(s): 125-129

Macrobenthic communities of the coastal waters of Dabhol, west coast of India

2009-05-30T16:30:27Z

Title: Macrobenthic communities of the coastal waters of Dabhol, west coast of India Authors: Ingole, Baban; Rodrigues, Nimi; Ansari, Zakir Ali Abstract: Macrobenthic community of a shallow subtidal (5-20 m) muddy deposit off Dabhol was investigated. Sediment comprised mainly of silt and clay with less of sand. Dominance of clayey-silt fraction reflects on active flocculation of fine grain particles. The sediment organic carbon with a mean value of 1.42% was rather high. The population density of macro-invertebrates varied from 250 to 600 no.m^-2 (mean=395±111) during December 1994. The values increased significantly during December 1996 and ranged between 400 and 975 no.m^-2 (mean = 621±194). Macrofaunal community comprised of typical near-shore species, numerically dominated by polychaetes. The sediment organic content reflects on the high biological productivity of the area, particularly benthic production that was evident from a good fish catch in the experimental bottom trawling. Values for species diversity followed more or less similar trends and less variability among the sampling stations in Dec.1994 and Dec. 1996. However, species composition indicated the dominance of different taxa among the sampling locations during two sampling years. The occurrence of juvenile forms of decapods (shrimps and crabs) in the benthic samples suggest that the coastal waters of Dabhol provide favourable environmental conditions for feeding and breeding of commercially important prawn and crab species. Page(s): 93-99

Book Review

2009-05-26T16:30:28Z

Title: Book Review Abstract: Prawns of Japan and the World [Ed-in-chief Chiaki Koizumi]
C.T. Achuthankutty Page(s): 165-166