Food and feeding of Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) (Brachyura: Portunidae) along Karnataka coast

The diet of Portunus (Portunus) sanguinolentus and P.(P.) pelagicus Jmlin1y consisted of crustacean Fishes, molluscs, large quantity of unidentified matter and debris. Quantitative analysis of the gut contents revealed that crustaceans contributed to 47.1% and 42.6 %, fish remains 29.0 % and 20.4 %. molluscs 5.7% and 20.0 % detritus 4.9 % and 4.7 % respectively of the gut content by volume in both species respectively. The study indicated that these crabs are primarily predators of sessile and slow moving benthic macro invertebrates

Length-weight relationship in two marine portunid crabs, Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) from the Karnataka coast

Portunus (Portunus) sanguinolentus and P.(P.) Pelagicus support fishery of considerable value all along the Indian coast and together contribute up to 96 % of the crab landings. In the context of increased importance of crab resources and interest eltinced in culture, there is an urgent need to study tlie biology and related aspects

Spawning biology of two marine portunid crabs, Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) from the Karnataka Coast

Weekly samples of P (P) sallguilloienllls and P (P) pelagicus caught by di !ferent type of gears were taken from Mangalore, Malpe and Karwar - three important fish landing centres in Kamataka during 1992-94 and analysed for carapace width, weight, sex and maturity conditions. For describing the gross maturity stages of ovary, the following stages were recognised. I) immature virgins, 2) immature resting 3) early maturing, 4) late maturing, 5) mature and 6) spent

The portunid crab Charybdis (charybdis) feriatus - An emerging fishery resource of Mangalore coast

The marine crab fishery by mechanised trawlers along the Mangalore coast is mainly supported by those belonging to the genera Portunus and Charybdis of the family Portunidae

Potential new resources of penaeid prawns of the Mangalore coast

Penaeid prawns belonging to the genera Parapenaeopsis, Penaeus and Metapenaeus of the family Penaeidae exploited by mechanised trawlers support a fishery of considerable magnitude along the Mangalore coast. Among the penaeid prawns exploited Metapenaeus dobsoni, M. Monoceros, M. qffinis, Parapenaeopsis stylifera, Penaeus indicus and P. monodon are important and contribute upto 90-99 % of the prawn catch along this coas

Maturation process and reproductive cycle in two marine crabs, Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) along the Karnataka coast

In the development of ovary of Portunus (Portunus) sanguinolentus and P. (P.) pelagicus, six maturity stages have been recognised by gross examination, i.e., immature virgins, immature resting, early maturing, late maturing, mature and spent. By microscopical studies, nine arbitrary stages have been identifed in the maturation process of ovary. In the development of testis, three maturity stages have been discernible, i. e., immature, maturing and mature. The spawning season is exended from August to May in both the species with intensive activity during December-February in the former and during January-February and September in the latter species

Age and growth in two marine portunid crabs, Portunus (Portunus) sanguinolentus (Herbst) and Portunus (Portunus) pelagicus (Linnaeus) along the southwest coast of India

Age and growth of two marine protunid crabs, Portunus (Portunus) sanguinolentus and P. (P.) pelagicus was investigated based on the data collected from the commercial catches landed at Mangalore, Malpe and Karwar, three major fish landing centres in Karnataka state, along the southwest coast of India during 1992-'94. The size frequency analysis indicated that the growth rate was high and more or less uniform in juveniles, while the adults showed relatively low rate of growth and marked variation in males and females. In P. (P.) sanguinolentus, the mean monthly growth rates were 10.3 m and 8.8 mm and attained a carapace width of 124.1 and 112.5 mm by males and females respectively on completion of one year. In P. (P.) pelagicus, the average growth rates were 11.0 and 9.6 mm and attained a size of 145.2 and 132.5 mm by males and females respectively, at the end of one year. The von Bertalanffy's growth parameters, L_, K and to were 195 mm, 0.99 yr1 and -0.0132 yr for males and 188 mm, 0.82 yr1 and -0.0975 yr for females. In P. (P.) pelagicus, the growth parameters were 211 mm,. 1.14 yr 1 and -0.0194 yr for males and 204 mm, 0.97 yr1 and -0.0691 yr for females

Apocyclops cmfri sp. nov. (Cyclopoda : Cyclopoida : Cyclopidae), a new copepod species from Arabian Sea off Karwar, Karnataka, India

A new species of Apocyclops Lindberg (Cyclopoda: Cyclopoida: Cyclopidae) is described based on specimens collected from marine waters of Karwar, Karnataka, India. At present, there are 11 valid and accepted species excluding one extinct species (fossil) in this genus which are widely distributed in fresh and brackishwater areas in the tropics and subtropics. Five valid species of Apocyclops are reported from the Asian region, including two species from India. The new species is closer to the previously reported Indian species, A. royi (Lindberg) and A. dengizicus dengizicus (Lepeshkin). Apocyclops cmfri sp. nov. differs from these in the size of caudal rami, in the characteristic shape of disto-medial part of coxa and basis of first to fourth pleopods (P1-P4) and in the presence of a single broad spinous expansion with a pointed tip in between exopod and endopod in basis of P1 to P4. Only one terminal spine is present in the second segment of endopod of P1. In P2 to P4, both exopod and endopod terminate in a spine and a seta of almost equal size. Maxillule highly dentate and maxilla basis form a large dentate claw with inner serration. All these characters form distinct identification features of the new species in comparison with the 12 accepted species under the genus. A key to all the species of the genus including the newly described species is proposed here. Molecular identification of the new species was carried out by mitochondrial cytochrome c oxidase 1 (CO1) gene sequencing and the sequence was submitted to NCBI, GenBank. Genetic differentiation and divergence between A. cmfri sp. nov. and species belonging to other closely related genera; Thermocyclops, Mesocyclops and Eucyclops were compared using CO1 gene sequences. The new species belonging to Apocyclops showed significant divergence from Apocyclops borneoensis with K2P value of 10.2% and from species under the genera Mesocyclops, Thermocyclops and Eucyclops with K2P values of 26.6, 27.5and 34.9% respectively

i-Rheo GT: transforming from time to frequency domain without artifacts

We present a new analytical tool for educing the frequency-dependent complex shear modulus of materials from computer-aided numerical simulations of their timedependent shear relaxation modulus; without the need of preconceived models. The rheological tool is presented in the form of an open access executable named ‘i-Rheo GT’, enabling its use to a broad scientific community. Its effectiveness is corroborated by analysing the dynamics of ideal single mode Maxwell fluids, and by means of a direct comparison with both bulk-rheology measurements and coarse-grained molecular dynamics simulations data transformed via a generalised Maxwell model. When adopted to transform atomistic molecular dynamics simulations data, the unbiased nature of the tool reveals new insights into the materials’ linear viscoelastic properties, especially at high frequencies, where conventional tools struggle to interpret the data and molecular dynamics simulations actually provide their most statistically accurate predictions. The wideband nature of i-Rheo GT offers the opportunity to better elucidate the link between materials’ topologies and their linear viscoelastic properties; from atomic length scales at frequencies of the order of THz, up to mesoscopic length scales of molecular diffusion phenomena occurring over time scales of hours

Stock assessment of the penaeid prawn Metapenaeus dobsoni (Miers) along the Indian coast

The annual prodiction of M. dobsoni showed an increasing trend with an annual average of 22 370 t during 1985-S9. It formed 15.7% of the penaeid prawn landings in the country. West coast contributed 69.9% to the annual yield of this prawn. Kerala ranked first (51.4%) in M. dobsoni production followed b;' Tamil Nadu. Shrimp trawl alone caught 54% of the landings. L«> and K were 139 mm and 2.4 for m«les, and 145 mm and 2.76 for females respectively. The instantaneous mortality coefficient (Z) ranged lietween 16,47 and 25.29 in males, and between 16.21 and 20.97 in females. Tlie natural mortality coefficient (M) was 2.3 for both the sexes. The yield per recruit (Yw/R) increased steadily to maximum values (MSY/R) in both the sexes at Emax ranging between 0.2 and 0.4. It marginally reduced at Ihe present E between 0.8 and 0.9 suggesting that the resource is overexploited and the current effort s far higher than the effort required to harvest optimum yields. Although the average annual catch by shrimp trawls (12 189 t) is lower than MSY (13 965 t), the annual effort of 6 920 tpd or 1 488 000 bd (F= 17.8 and E = 0.89) is far beyond f^,. Considering the fact that this prawn is also exploited by other gears with an annual average of 10 180 t during 1985-89, a conservative estimate of 25 000 t as potential stock for the whole country is made