Indian Council of Agricultural Research


Biological aspects of spotted seerfish Scomberomorus guttatus (Scombridae) from north-eastern Arabian Sea

Spotted seerfish Scomberomorus guttatus (Bloch & Schneider, 1801) is one of the highly priced table fishes in India, which contributed 4.7% of all India scombrid fishery with 17,684 t landed in 2014. Its fishery is dominant in the Arabian Sea and northern Arabian Sea contributed 62% to India’s spotted seerfish fishery. Biological information on S. guttatus is scarce and the same was studied during the period 2010-2014 from Maharashtra coast, north-eastern Arabian Sea. A total of 930 specimens (185-550 mm FL) collected from commercial landings were used for the study. Length-weight relation of pooled sexes was estimated as log (W) = -3.1988+2.66074 log (L) (r2 = 0.93). Fishery was dominated by males with the sex ratio of 0.76:1. Relative fecundity ranged from 105-343 eggs g-1 of bodyweight. The length at first maturity (Lm) was estimated to be 410 mm TL for females. Mature and gravid females were dominant in May and August-November. Dietary studies (% IRI) showed dominance of Acetes spp.


Fishery and stock status of cuttlefishes off Andhra coast, India with focus on the needle cuttlefish

The fishery and stock status of cuttlefishes along the northern coast of Andhra Pradesh was studied with special reference to the needle cuttlefish; Sepia aculeata Van Hasselt, 1835. Cuttlefishes caught by trawlers along the coast of Andhra Pradesh contributed 68.29% of the total cephalopod landings of the state during the study period (2006-2016). The average annual cephalopod landing in Andhra Pradesh for the study period was 2991 t and the mean annual catch per hour (CPH) during 2006-2016 was 0.47 kg h-1. The cumulative sum (CUSUM) analysis indicated increasing trend in cuttlefish landings of the state during the study period. Stock status plots indicates that cuttlefish stocks along the Andhra Pradesh coast are in the “fully exploited” phase.


Antioxidant and anti-inflammatory oxygenated meroterpenoids from the thalli of red seaweed Kappaphycus alvarezii

Three antioxidant and anti-inflammatory oxygenated meroterpenoids, 1-(3-methoxypropyl)-2-propylcyclohexane (C13) (1), 3-(methoxymethyl)heptyl 3-(cyclohex-3-enyl) propanoate (C18) (2), and 2-ethyl-6-(4-methoxy-2-((2-oxotetrahydro-2Hpyran- 4-yl)methyl)butoxy)-6-oxohexyl 5-ethyloct-4-enoate (C29) (3) were purified from the methanol:ethyl acetate fraction of red seaweed Kappaphycus alvarezii (family Solieriaceae) collected from the Gulf-of-Mannar on the southeast coast of peninsular India. The highly oxygenated C29 meroterpenoid 3 displayed potential antioxidative activities (IC50 < 0.35 mg/ mL) as evaluated by 2, 2’-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid and 1, 1-diphenyl-2-picryl-hydrazil free radical scavenging assays. The compound 3 displayed potential in vitro inhibitory activities towards pro-inflammatory 5- lipoxidase (IC50 1.04 mg/mL), which indicated its potential anti-inflammatory properties against inducible inflammatory mediators causing an inflammatory response. Structure-activity relationship analyses displayed the functional roles of lipophilic-hydrophobic characteristics and electronic parameter to determine its potential anti-inflammatory activity in terms of inhibiting inducible inflammatory cyclooxygenase and lipoxidase.


Relating abundance of purpleback flying squid in the south-eastern Arabian Sea

The distribution pattern of purpleback flying squid and the relationship between its abundance and environmental variables in the south-eastern Arabian Sea were analysed using a geographical information system (GIS) and a generalised additive model (GAM). Highest abundances were observed during December and January within 10 and 13°N and 71 and 72°E around the Lakshadweep Islands. The mean abundance in the area was 4.21 tonnes/km2 and the maximum sustainable yield (MSY) was estimated as 0.63 million tonnes. GAM indicated that very high squid abundance was associated with low values of dissolved oxygen (6.01–6.27 mg/L), sea surface temperature (28.03–28.62°C), pH (7.75–8.56), salinity (30.42–34.48 psu), chlorophyll-a (0.4–0.6 mg/m3), zooplankton biomass (0.23–0.64 mL/m3), and shallow 20°C isotherm (101.2–134.7 m) and mixed layer depth (17.8–29.8 m). As a carnivore from paralarval stages, S. oualaniensis depends on secondary and tertiary production to sustain its population for which primary production is used up. In the tropical Arabian Sea where temperature differences are not so pronounced, S. oualaniensis distribution was found to be related to a low but very narrow sea surface temperature (SST) band. There is sufficient fishable biomass in the area to possibly launch a new targeted oceanic squid fishery from the western seaboard of India.


Antioxidative sulphated polygalactans from marine macroalgae as angiotensin-I

Antioxidant and antihypertensive potential of the sulphated polygalactans isolated from the marine macroalgae Kappaphycus alvarezii and Gracilaria opuntia were assessed by utilising different in vitro systems. The galactans isolated from K. alvarezii possessed significantly greater antioxidative properties as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH IC90 0.97 mg/mL) and 2,2?-azino-bis(3-ethylbenzothiazoline-6- sulphonic acid (ABTS.+ IC90 0.72 mg/mL) scavenging activities than those isolated from G. opuntia (DPPH IC90 1.2 mg/mL and ABTS 0.86 mg/mL). The sulphated polygalactan ?4)-4-O-sulphonato-(2-O-methyl)-?-Dgalactopyranosyl-( 1?4)-3,6-anhydro-(2-O-methyl)-?-D-galactopyranan from K. alvarezii showed greater angiotensin-I-converting enzyme (ACE) inhibitory activity (IC50 0.02 ?g/mL) than ?3)-4-O-sulphonato-(6-Oacetyl)- ?-D-galactopyranosyl-(1?4)-3,6-anhydro-(2-O-sulphonato)-?- D-galactopyranosyl-(1?3)-4-O-sulphonato-(6-O-acetyl)-?-D-xylosyl- (1?3)-4-O-sulphonato-(6-O-acetyl)-?-D-galactopyranosyl-(1?4)-3,6- anhydro-(2-O-sulphonato)-?-D-galactopyranan motif extracted from G. opuntia (IC50 0.70 ?g/mL). Structure activity correlation studies displayed that the ACE inhibitory properties of titled polygalactans were directly proportional to their electronic properties and inversely with the steric and hydrophobic characteristics. Putative ACE inhibitory mechanism of action of sulphated galactans from marine macroalgae corroborated the structure bioactivity correlation analysis.


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