Corollary of Marine Eco-system Sustainability by Addressing the Issues of Bycatches

The issue of bycatch in fisheries sector has been a major concern for the marine biologists over few decades in terms of conservation of marine eco-system and sustainability of the fisheries sector and marine biodiversity. Bycatch generally include species of little commercial importance, which in most cases is dumped overboard either into the sea or after reaching the fish landing sites. The article discusses the ecological, economic, legal, social influences, and the importance in addressing the issue of bycatch. The concept of bycatch is relatively new in the horizon in Indian perspective as it is often considered major issues by developed nations which are characterised by highly mechanised and industrialised fisheries. The problem of bycatch is seen as the depletion of this food source for local consumption and therefore a threat to livelihoods and food security in general and it has environmental, economic, socio-cultural impacts. The adverse effects of by-catch can be mitigated through commercialisation of bycatch and making profits from the sale of bycatch, opening up of new markets for bycatch species or products, uses of fishmeal as feed in the poultry and aquaculture industries and application of bycatch reduction devices (BRDs). The revamping the present monitoring system used to collect fisheries data, strengthening technical know-how, bringing effective policy intervention, efficient co-management, and sincere and honest efforts in reducing bycatch and discards may provide a considerable impact towards sustainability of marine eco-system

Channel Controlled Foraminiferal Distribution off Bakkhali, West Bengal, India

Study area is situated 8 km south of the Bakkhali Island, West Bengal of India and its subaqueous environment influenced by the fluvial processes such as Hooghly River in west and its distributary like Muri Ganga in the centre and Saptamukhi River in the east. To understand the submarine behavior of these channels and associated meiobenthos, total of 28 sediment samples have been studied in detail. The study reveal that a total of fifteen species of recent benthic foraminifera belonging to 13 genera under 11 families were present and their distribution mainly controlled by channel morphology and sediment character. Based on the distribution of these benthic foraminiferal species, two assemblages have been identified. First assemblage, observed within the Hooghly and Muri Ganga channel, where salinity is comparatively low and sediment is mainly dominated by silt and clay. The most dominating benthic foraminifers of this assemblage are Ammobaculites agglutinans, Cribrostomoides jeffreysii and Asterorotalia trispinosa. Whereas, second assemblage mainly comprise of A. trispinosa, Ammonia beccarii, Asterorotalia spp., Elphidium excavatum, Elphidium crispum and Ammonia tepida noticed over the sand bars and adjoining shallow area. Keywords: channel morphology, Muri Ganga, Hooghly, sand ba

Bartonian reticulate Nummulites of Kutch

Nummulites with reticulate septal filaments stratigraphically span from the Bartonian to the Rupelian Stages. The size of the proloculus of the megalospheric forms of reticulate species helped recognise N. fabianii – N. fichteli lineage in western Tethys. Unlike the species of this lineage, N. ptukhiani, described from Armenia, is characterised by an unusually large proloculus. A possibly second lineage of reticulate species comprising N. ptukhiani is recently reported from Lutetian – Bartonian succession of Tanzania. The present study examines reticulate species from palaeogeographically adjacent Bartonian succession of Kutch. The statistical analysis of the biometric data suggests the presence of three distinct species, referred to Nummulites ptukhiani, N. aff. hormoensis and N. acutus. The reticulation starts developing in N. acutus that ranges from P13 to P14 in its type locality, Kutch. We infer that Nummulites ptukhiani and N. aff. hormoensis possibly evolved from N. acutus in Zone P14. A binary tree model based on Classification and Regression Tree is proposed to statistically discriminate the three reticulate species

Geometrical isomer preference of Ru<SUP>II</SUP> and Ru<SUP>III</SUP>: chemistry and structure of a RuS<SUB>4</SUB>P<SUB>2</SUB> family. Crystal structure of [Ru(PhCH<SUB>2</SUB>SCS<SUB>2</SUB>)<SUB>2</SUB>(PPh<SUB>3</SUB>)<SUB>2</SUB>]

The syntheses of mixed thioxanthate (trithiocarbonate)-phosphine complexes of types cis-[Ru(RSCS2 )2(PPh3)2](1) and trans-[Ru(RSCS2)2 (PPh3)2]PF6(2+) are reported (R = Et, Pri, or PhCH2). These along with trans-[Ru(RSCS2)2(PPh3) 2](2) and cis-[Ru(RSCS2)2(PPh3)2] +(1+) constitute an electrochemically observable redox isomerisation cycle. The formal potentials of the couples (1+)-(1) and (2+)-(2) are ≈ 0.65 and ≈ 0.33 V respectively vs. saturated calomel electrode (s.c.e.). The isomerisation steps are (1+)→(2+)(fast) and (2)→(1)(k≈ 7.0 x 10-2 s-1). The X-ray structure of complex (1; R = PhCH2) has been determined: space group C2/c, a= 18.676(7), b= 10.511(2), c= 24.432(8)Å , and Z = 4. The superior stability of the cis configuration of RuII for complexes (1) arises primarily from the strong back-bonding (cis &gt; trans) within the Ru(PPh3)2 fragment. For RuIII, in which back-bonding is unimportant, the stable geometry is trans owing to favourable steric disposition of the PPh3 molecules. The frozen glass e.s.r. spectra of complexes (2+) have a sizable axial distortion (Δ≈ 8 500 cm-1) with a relatively small rhombic component (V≈ 2 200 cm-1). One of the two predicted transitions (∨ 1≈ 7 500 and ∨2≈ 9 900 cm-1) within the t2g shell is observable (∨1≈ 6 500 cm-1) in the near-i.r. region

Chemistry of the ruthenium [Ru(RQ)(tap)<SUB>2</SUB>]z family: authentic catecholates, reduction potentials, and spectra (RQ = quinone/semiquinone/catecholate; tap = 2-(m-tolylazo)pyridine; z = 0, &#177; &#177;2)

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Geometrical isomerism of bis(alkyl trithiocarbonato-S,S')bis-(triphenylphosphine) complexes of osmium-(II) and -(III)

Complexes of types [Os(RSCS<SUB>2</SUB>)<SUB>2</SUB>(PPh<SUB>3</SUB>)<SUB>2</SUB>]<SUP>z</SUP>(cis-Os<SUP>II</SUP>, z= 0, 1; cis-Os<SUP>III</SUP>, z=+, 1<SUP>+</SUP>; trans-Os<SUP>II</SUP>, z= 0, 2; and trans-Os<SUP>III</SUP>, z=+, 2<SUP>+</SUP>) have been prepared, but 1<SUP>+</SUP> is observable only in solution. The 2<SUP>+</SUP> salts are paramagnetic (S=½) and display rhombic EPR spectra which have been analysed; a relatively weak electronic transition observed in NIR region is assigned to excitation from one Kramers doublet to another. Electrochemical and spectral data have been used to characterise the coupled redox and isomerisation processes interlinking 1, 1<SUP>+</SUP>, 2 and 2<SUP>+</SUP>. Upon oxidation 1 affords 1<SUP>+</SUP> which isomerises to 2<SUP>+</SUP> relatively rapidly. On the other hand, 2<SUP>+</SUP> can be reduced to 2 which slowly but spontaneously isomerises to 1. Rate and equilibrium data are reported. The electronic and steric factors controlling isomer preference [cis for osmium(II) and trans for osmium(III)] are noted. Compared to the present complexes, the ruthenium congeners isomerise more rapidly and more completely

Paramagnetic organometallics formed by o-metallation of phenolic Schiff bases by ruthenium(III)

The reaction of Ru(PPh<SUB>3</SUB>)<SUB>3</SUB>X<SUB>2</SUB> (X= Cl, Br) with the Schiff base condensate of 4-substituted benzaldehyde (RC<SUB>6</SUB>H<SUB>4</SUB>CHO) and 2-aminophenol under aerobic conditions affords the complexes Ru<SUP>III</SUP>(RL)(PPH<SUB>3</SUB>)<SUB>2</SUB>X in which RL is the Schiff base ligand bound to the metal centre at the phenolic oxygen (deprotonated azomethine nitrogen and an ortho carbon atom (deprotonated) of the benzaldehyde fragment. The complexes behave as one-electron paramagnets; and give rhombic EPR spectra, that have been analysed to furnish values of axial and rhombic distortion parameters as well as the energies of the two expected ligand field transitions within the t<SUB>2</SUB> shell. One of the transitions has been experimentally observed in the predicted region. The complexes are electroactive and display ruthenium(III)- ruthenium(II) (E<SUB>&#189; </SUB> -0.5 to -0.8 V vs. SCE) and ruthenium(IV)-ruthenium(III) (E<SUB>&#189;</SUB> 0.4 to 0.8 V) couples. The E <SUB>&#189;</SUB> values vary linearly with the Hammett constant of the substituent R. The role of phenolato-coordination in stabilizing the trivalent state of ruthenium is noted

Isomer preference of oxidation states. Chemistry of the bis(triphenylphosphine)bis(xanthato)osmium(z) (z = 0, +) family

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