1,876 research outputs found
Age and growth of three species of seerfishes Scomberomorus commerson, S. guttatus and S. lineolatus
Length-frequency an:(lysis indicates that the king seer (Scomberomorus cotnmerson)
attains a size of 402 mim, 726 mm, 995 mm and 1186 mm total length
at 1, 2, 3, and 4 years of age, respectively, the streaked seer (S. Uneolatus) reaches
a size of 350 mm, 713 mm, 835 mm and 965 mm total length et 1, 2, 3 and
4 years, respectively, and the spotted seer (S. guttatus a size of 369 mm, 532
mm: and 640 mm at 1, 2, and 3 years, respectively. Back-calculated lengths of fish
at the time of ring formation on otoliths figree closely with the results of lengthfrequency
analysis. The maximum lengths of king seer, streaked seer and spotted
seer met with in the catches are 1936 mm (33 kg), 980' mm (4.6 kg) and 705
mm (2.1 kg), respectively. The theoretical maximum lengths (Lac) computed by
Bagenal or Rafail method for the von Bertsfeaffy growth equation are found to be
2081 mm (46.7 kg) for the king seer, 1683 mm (15.7 kg) for the male streaked
seer, 1447 ram (24.3 kg) for the female streaked seer and 1278 mm (9.6 kg) for
the spotted seer. All the three species develop two rings a year in their otoliths
at a regular interval of six months. For all the three species, the exponent in the
length-weight relationship is found to be close to 3
Deepsea fishing in Indian waters
The development of Indian marine fIsheries
since the early 60s from a traditional,
subsistence oriented one into an industrial
fisheries was quite substantial. This change got
accelerated mainly in the mechanised era of
the marine fishery sector. Although with the
declaration of the EEZ, an area of 2 million
sq. km. came into existence in 1977, there has
never been a commercial deepsea fishing worth
mentioning. However deepwater trawling
conducted by two Mexican trawlers (24 m
OAL) imported from the USA in 1972 has
paved the way for a humble beginning in the
deepsea fishing operations. Gradually by
1982-83 about 11 0 chartered and joint venture
deepsea fishing vessels began fishing operations
and almost without exception, they exploited
mostly the inshore grounds upto 50 m and
rarely upto 100 m. But once the depth limitations
beyond the 80 m depth line for offshore fIshing
operations was enforced in 1983, almost all these
chartered vessels left the country
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Need for a systems approach to the development of the coastal agroecosystems in the Gulf of Mannar area
The Gulf of Mannar is bordered by Ramanathapuram, Thoothukudi, Thirunelveli and Kanyakumari districts. Most ofthis coast is dry, and experiences only limited rainfall during the northeast monsoon. The mainstay of the population is comprised by marine fisherfolks, marginal farmers and landless labourers
Coastal biodiversity - Conservation and sustainable management
A management regime based on social acceptance, with the power
of moral persuasion from within the group of participants, is the
only way to manage widely dispersed resources which are sliared
by a multitude of small scale fishermen and various other users
Fishery biology research: glimpses on practices and application for genetic resource conservation
India is bestowed with rich natural resources in which the freshwater, coastal and marine living resources are of
prime importance in view of the total dependence of the humanity on these resources for its well-being. Sustained
anthropogenic activities such as fishing, coastal industries, shipping and ports, ship breaking, dredging, agriculture and
land based industries have profound impacts on these resources ranging from least serious to most serious in nature
prompting appropriate regulatory and conservation measures
The seerfish resources
The seerfishcs are inshore pelagic fishes, distributed mainly in
areas within 60 m depth contour. The mean annual seerfish catch
of 17,852 t for 1964-81 was accounted for almost equally by the
east coast (49.66%) and the west coast (50.34%). While the bulk
of the east coast catch came from Tamilnadu (47.91%) tod Andhra
Pradesh (40.34%), the States of Kerala (35.48%), Maharashtra
(23.44%) and Gujarat (23.14%) contributed the bulk to the west
coast. The progressively increasing trend from 1964 to 1981
owes to the increasing number of mechanised gilhietters operating
for the larger catch including the seerfishes.
(23.44%) and Gujarat (23.14%) contributed the bulk to the west
coast. The progressively increasing trend from 1964 to 1981
owes to the increasing number of mechanised gilhietters operating
for the larger catch including the seerfishes
Stock assessment implications and management options for the small pelagics in the APFIC region
Problems in stock assessment and management of the exploited fish stocks, especially the pelagic fish stocks, are reviewed. The theoretical and practical constraints in the application of the assessment techniques and
production modelling with reference to the small pelalgics are indicated. Appropriate approaches to pelflgic fish stock assessment and management are outlined
Splash wave and crown breakup after disc impact on a liquid surface
In this paper we analyze the impact of a circular disc on a free surface
using experiments, potential flow numerical simulations and theory. We focus
our attention both on the study of the generation and possible breakup of the
splash wave created after the impact and on the calculation of the force on the
disc. We have experimentally found that drops are only ejected from the rim
located at the top part of the splash --giving rise to what is known as the
crown splash-- if the impact Weber number exceeds a threshold value
\Weber_{crit}\simeq 140. We explain this threshold by defining a local Bond
number based on the rim deceleration and its radius of curvature,
with which we show using both numerical simulations and experiments that a
crown splash only occurs when , revealing that the rim
disrupts due to a Rayleigh-Taylor instability. Neglecting the effect of air, we
show that the flow in the region close to the disc edge possesses a
Weber-number-dependent self-similar structure for every Weber number. From this
we demonstrate that \Bond_{tip}\propto\Weber, explaining both why the
transition to crown splash can be characterized in terms of the impact Weber
number and why this transition occurs for .
Next, including the effect of air, we have developed a theory which predicts
the time-varying thickness of the very thin air cushion that is entrapped
between the impacting solid and the liquid. Our analysis reveals that gas
critically affect the velocity of propagation of the splash wave as well as the
time-varying force on the disc, . The existence of the air layer also
limits the range of times in which the self-similar solution is valid and,
accordingly, the maximum deceleration experienced by the liquid rim, what sets
the length scale of the splash drops ejected when We>\Weber_{crit}
CIFE contribution to marine fisheries R & D
The CIFE contributions to marine fisheries R&D are mainly In the areas of stock assessment, brackish water farming, fishing and product
diversification, fishery socio-economics and technology transfer. Stock assessment studies, limited to the west coast and particularly to the
northwest coast Include the stocks of Co///a dussumleii, Otolilhus cuvleri, Johnlus glaucus, Polynemus heptadactylus, Harpodon nehereus, Arius
thalasslnus, Nemlpterus japonlcus, all-northwest coast Inshore species, penaeid prawns, Rastrelllger kanagurta, Sardlnella longiceps and xancus
pyrum. In respect of brackish water fisheries, R & D acclivities are concerned with prawn hatcheries, seed banks, low Input culture, live feed culture
and fishery estates. Simple techniques for making laminated Bombay duck, fish wafers and minced meat have been developed for the purpose of
product diversification. High opening bottom trawling has been experimentally proven to be more productive than the traditional bottom trawling,
and Is being popularised. Studies on profitability of mechanised fishing indicate some prospects for additional Investment. Small private owned
brackish water farms are more profitable than large government owned farms, Indicating thereby the need to privatize the farm sector. The fisherie
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