2,085 research outputs found
Guidelines for identification of postlarvae
From the morphological resemblances and the progress
of changes in morphology accompanying growth, it is possible
t o trace tho development of fishes. However, the easiest
means in identifying fish larvae is t o identify the largest
stage and work down to the smallest
Guidelines for the identification of larvae
The different stages or phases in the life history
of fishes markedly vary from the adult and the degrees of
difference vary in different groups. However, there is
no sudden metamorphosis in fishes and the change of form
is slow. The differences between the larvae and adults
of some fishes have led erroneously to the descriptions
of the early stages of eel as Leptocephalus, Molidae as
Molacanthus and Centaurus. Chaetodontidae as Tholichthys,
Schindleria as Heiinirhamphus and Lampreys as Ammocoetus,
Later, these generic names were given the status of stages
in the early life history of the fish concerned
Our fisheries resources and the role of upwelling in their fluctuations Part II: Primary productivity and fisheries potential
The availability of essential nutrients in the productive upper layers is one of the important factors governing the magnitude of organic production. The nutrients are brought up into the euphotic zone by the vertical mixing of the water caused by wind and wave action; processes associated with ocean currents and by upwelling of deep water
Our fisheries resources and the role of upwelling in their fluctuations Part III The role of upwelling on fluctuations
The ecological relationship between fishes and their environment is of great practical application in fisheries. For any large scale development of our fishery
resources a better understanding of the environmental factors influencing the reSources is essentia
Our fisheries resources and the role of upwelling in their fluctuations Part I marine fish production of India
The ecological relationship between fishes and their environment is of great practical application in fisheries. For any large scale development of our fishery
resources a better understanding of the environmental factors influencing the reSources is essentia
Temperature scaling in a dense vibro-fluidised granular material
The leading order "temperature" of a dense two dimensional granular material
fluidised by external vibrations is determined. An asymptotic solution is
obtained where the particles are considered to be elastic in the leading
approximation. The velocity distribution is a Maxwell-Boltzmann distribution in
the leading approximation. The density profile is determined by solving the
momentum balance equation in the vertical direction, where the relation between
the pressure and density is provided by the virial equation of state. The
predictions of the present analysis show good agreement with simulation results
at higher densities where theories for a dilute vibrated granular material,
with the pressure-density relation provided by the ideal gas law, are in error.
The theory also predicts the scaling relations of the total dissipation in the
bed reported by McNamara and Luding (PRE v 58, p 813).Comment: ReVTeX (psfrag), 5 pages, 5 figures, Submitted to PR
Distribution of larval tuna collected by the Carlsberg foundation's Dana expedition (1928-30) from the Indian Ocean
The geographical and seasonal distribution of larvae of five species
of tuna (Katsuwonus elamis, Neothunnus macropterus, Euthynnus affinis
affinis, Auxis thynnoides and Auxis thazard in the Indian Ocean based
mainy on the collections made by the 1928-30 Dana Oceanographical Expedition
are dealt with
Notes on eggs, larvae and juveniles of fishes from Indian waters XV Pegasus volitans Linnaeus. XVI Dactyloptena orientalis (Cuvier and Valenciennes) and XVII Ddactyloptena macracanthus (Sleeker)
Three species of pegasids viz., Pegasus volitans Linnaeus, P. laternarim Cuvier
and P. draconis Linnaeus have been recorded from the seas around India. Of these,
Pegasus draconis is distinct from the other two by the presence of 8 tail rings
and 2 pits on occiput. P. volitans differs from P. laternarius mainly in having 12
tail rings as against 11 tail rings in the latter. P. natans is considered synonym of
P. volitans (vide De Beaufort, 1962) and hence the larval and juvenile specimens
collected from the Orissa coast (Jones and Pantulu, 1958) and the postlarva collected
from Porto Novo (Krishnamurthy, 1962) should be known under P. volitans
The fishing industry of Minicoy Island with special reference to the tuna fishery
The coral island of Minicoy (Fig. 1 a and b) in the Indian Ocean (Latitude
8┬░ 7' N., Longitude 73┬░ 18' E.) is the most important tuna fishing centre in
the Indian Union (Fig. 1). Situated between the two main groups of islands
of the Laccadive and the Maldive Archipelagoes, it is about 10 km. long
and 820 m. broad in the centre and has an area of about 455
hectares and population of about 4,000 who speak the same Mahl dialect as
the Maldivians to whom they are related ethnically. The main port of
trade in India for the islanders is Cannanore about 420 km. away on the
Malabar coast and specially built sailing vessels known as odams are used
for carrying men and cargo to the mainland and back. Tuna fishery is the
most important industry of the island and the chief product of export is
the mas min or the cured and dried meat of tuna the value of which has
recently risen to the record figure of over half a million rupees a year. Export
of cured tuna meat contributes about two-thirds of the total income of the
islanders while next in order of importance comes the money remitted by
those serving as lascars in merchant vessels. The only other source of
income is from the sale of produce like copra, jaggery, coir and vinegar
from coconuts. There is practically no other source of revenue and the
inhabitants have to depend entirely on the mainland for all essential items
and necessities of daily life such as rice and other commodities. In view
of this, a barter system of trade prevails there and the necessary goods are
supplied by certain merchants at Cannanore directly or through their
agents stationed in the island
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