15 research outputs found
Stock assessment of seerfishes in the Indian seas
The annual average catch of seerfishes from the Indian seas was 45,0601 during
1995-'99, which constituted 1.8% of the total marine fish catch in India. State-wise
Gujarat (28.5%) was the major producer followed by Tamilnadu (15.8%), Maharashtra
(15.4%), Andhra Pradesh (11.4%) and Kerala (10.5%). Gill net is the dominant
gear in exploiting seerfish followed by trawl, hooks & line, boat seines, shore seines
and purse seines. Among the five species, the kingseer Scomberomorus commerson
(59.0%) and the spotted seer S. guttatus (35.1%) sustained the fishery, while the
streaked seer S.lineolatus and the wahoo Acanthocybium solandri formed only a
negligible portion of the fisher
Status of exploitation of seerfishes in the Indian seas
Seerfish production from the Indian seas during the past five decades from 1950s to
1990s, showed an increasing trend. The annual catch increased from 4,505 t in
1953 to 54,8761 in 1998. The average annual catch during the five decadal periods
k-aried from 7,278 t in 1950-'59 to 41,575 t in 1990-'99 contributing 1.5% and
1.75% respectively to the total marine fish catch of India. However, the rate of
increase through the successive decades decreased indicating the attainment of op-
;imum level of production currently. During 1950-'59, the east coast contributed
more (60%) than the west coast (40%), which changed to 36:64 during 1990-'99.
iVmong the maritime states of India, Gujarat (25.88%), Maharashtra (16.09%),
familnadu (13.59%), Kerala (13.07%) and Andhra Pradesh (12.68%) were the prime
seerfish producers during 1990-'99. Gill net (64.8%) was the dominant gear, folowed
by trawl (17.4%) and hooks and line (4%) with an average catch rate of 8.1
<g/unit, 0.24 kg/hr and 3.7 kg/unit respectively during 1995-'99. Among the five
species, the fishery was sustained only by two species viz., the king seer
Scomberomorus commerson and the spotted seer S.guttatus
Stock assessment of coastal tunas in the Indian seas
Tuna and billfish production from the Indian coastal waters, Lakshadweep and
Andaman and Nicobar islands during the period 1985-'99 averaged 40,204 t. The
contribution by E.affinis, Athazard, T.tonggol, K.pelamis and T.albacares (young
ones) were 18,5041,6,8521,3,093 t, 3,3921 and 2,2111 respectively. Drift gill net
was the major gear employed in the coastal tuna fishery. The length frequency data
collected on the above species during 1990-'98 at seven centres along the Indian
coast were analysed employing FiSAT programme to estimate their growth and
mortality parameters, exploitation rates and relative yield per recmit
Status of exploitation of coastal tunas in the Indian seas
Tuna and billfish production from Indian seas during the period 1985-'99 evinced an
increasing trend and the landings fluctuated between 24,287 t (1987) and
53,6621 (1992). The average annual production during the said period was 40,2041,
contributing to 3.6% of the total pelagic fish landings and 1.8% of the total marine
fish landings. On an average, 24% of the total tuna and billfish production during
1991-'99 was contributed by northwest coast, 2% by Andaman and Nicobar islands
and 14.9% by Lakshadweep. Among the maritime states, Kerala (36 %), Gujarat
(18.1%) Tamilnadu (11.6%), Maharashtra (5.9%), Kamataka (5%), Andhra Pradesh
(4.4 %) and Goa (2%) were the prime tuna producing states
Novel One-Pot Synthesis of Luminescent Neutral Rhenium-Based Molecular Rectangles.
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Luminescence quenching of Re(I) molecular rectangles by quinones
The rhenium-based rectangles [{Re(CO)<SUB>3</SUB>(μ-bpy)Br}{Re(CO)<SUB>3</SUB>(μ-L)Br}]<SUB>2</SUB> (I, L = 4,4'-dipyridylacetylene (dpa); II, L = 4,4'-dipyridylbutadiyne (dpb); III, L = 1,4-bis(4'-pyridylethynyl)benzene (bpeb); bpy = 4,4'-bipyridine) are emissive in solution at room temperature. The presence of extended π conjugation leads to an increase in electron delocalization, which, in turn, results in improved luminescence and lower nuclear reorganization energy. These rectangles, upon electronic excitation, undergo facile electron transfer (ET) reactions with quinones and both the dynamic and static quenching contribute to the reaction. Spectral and electrochemical measurements show that quinone 7,7,8,8-tetracyanoquinodimethane (TCNQ) binds strongly to rectangle I. The driving force dependence of k<SUB>et</SUB>, deduced from the luminescence quenching of rectangles with quinones, can be well accounted for within the context of the Marcus theory of electron transfer