310 research outputs found
Fishery of sciaenids off Veraval with special reference to growth, mortality and stock assessment of Otolithes cuvieri (Trewavas, 1974)
Sciaenids form an important demersal finfish resource off Veraval and contribute
about 12 % to the total marine landings. They are exploited mainly by trawls
and gillnets with an annual average landing of 9086 t and 323 t respectively
during 1986-95. Nearly 16 species contribute to the sciaenid fishery of which,
Otolithes cuvieri and Johnius glaucus contributed 52.6% and 13.8 % respectively.
In gill net seven species contribute to the landings, dominated by Otolithes cuvieri
and Protonibea diacanthus. The peak landing of sciaenids was noticed in
September and January. Studies on O. cuvieri revealed that there was no
significant difference in the length weight relationship between the sexes, and
hence a common regression was fitted as Log W = -4.4632 + 2.9701 Log L
(r=0.9036). The asymptotic length (L ) and growth coefficient (K) were estimated
as 382 mm and 0.89 y-1 respectively. O. cuvieri grows to 225, 317, 354, 371 and
382 mm at the end of 1st, 2nd, 3 rd, 4th and 5th years. The fishery mainly
consisted of 0 and 1 year classes. The average instantaneous rates of total,
natural and fishing mortalities were 2.86 y-1, 0.81 y-1 and 2.05 y-1 respectively.
The length at first capture was 148 mm at which the age works out to be 0.5
year. The exploitation ratio is higher than the Emax estimated indicating that
the resource is overexploited. In view of the heavy fishing pressure, there is a
need for reducing the fishing effort to sustain the fishery
Sighting of a rare whale
Indopacetus pacificus (Longman, 1926), LongmanтАЩs
beaked whale (also known as Indo-pacific beaked whale
or tropical bottlenose whale) is a rare ziphid restricted to
tropical waters of Indian and Pacific Ocean
Fishery, biology and stock assessment of Cynoglossus macrostomus (Norman) off Malabar coast
Cynoglossus macrostomus formed 93 % of the annual average landings of
flatfishes (3951 t) during 1993-2004 at Calicut. The fishery showed annual
fluctuations. Peak landings were recorded during December-April. Growth
parameters of this species were L! = 164.5 mm y-1 and K = 0.70y-1. The fish
grows to 83, 124 and 146 mm at the end of 1-3 years. The total and natural
mortality were 3.01 y-1 and 0.91 y-1 respectively. The length-weight relationship
shows that the growth is isometric and there is no significant variation between
sexes. The spawning is prolonged with two peaks. The length at first maturity
is 102 mm. Females dominated the fishery. The stock is exploited marginally
below the optimum level at present. The total and standing stock of this species
along the Calicut coast is estimated as 5430 t and 1720 t respectively
Rare landing of devil ray, Manta birostris, at Calicut
A female devil ray, Manta
birostris, measuring 342 cm
length and 594 cm breadth,
weighing approximately 1400 kg,
was caught by a trawler at
Beypor
An account on the smallest whale shark, Rhincodon typus (Smith 1828) landed at Calicut
Whale shark landings in India are mainly due to incidental catches and mostly discarded. This report gives details on the smallest whale shark, that landed at Calicut
Food and feeding habits of Decapterus russelli (Ruppell, 1830) along the Malabar coast
Study on the food and feeding habits of Decapterus russelli showed that it is a carnivore, subsisting
mainly on crustaceans, fishes, polychaetes, salps, molluscs and miscellaneous items. Crustaceans
were the most dominant item in different size groups. The fish showed preference to other food
fishes as they grew. The intensity of feeding was high during most of the months. Feeding intensity
was high in juveniles followed by immature, maturing and spent fishes
Fishery of threadfin breams with some aspects on the biology and stock assessment of Nemipterus mesoprion (Bleeker, 1853) off Malabar coast
The average annual catch of threadfin breams along the Malabar coast was
16,754 t during 1998-2005. The fishery was constituted by Nemipterus japonicus
(46.8 %) and N. mesoprion (53.2 %). Peak landings were noticed during August-
September. Studies on N. mesoprion revealed that there is no significant
difference in the length weight relationship between sexes, and hence a common
equation was fitted as Log W = -3.9620+2.8298 Log L. The asymptotic length
(L ) and growth coefficient (K) were estimated as 299 mm and 0.79 y-1
respectively. N. mesoprion grows to 164, 238, 271 and 287 mm at the end of
first, second, third and fourth years. The total mortality, fishing mortality and
natural mortality were 4.93 y-1, 3.41 y-1 and 1.52 y-1 respectively. The length at
first capture was 105.4 mm. The resource is over exploited, and hence there is a
need for reducing the fishing pressure to sustain the fishery
First record of hound shark, Mustelus mosis from Calicut
Occurrence of a houndshark,
Mustelus mosis, was noticed
during the last week of May, 2010 in the
landings of multi-day trawlers operating
from at Beypore. Musteus mosis, belongs
to the family Triakidae, inhabiting the
continental shelves of western Indian
ocean at depths ranging between 200
and 250 m
Maturation and spawning of Decapterus russelli (Ruppell, 1830) along the Malabar Coast
The spawning period of the Indian scad Decapterus russelli, as indicated by ova diameter frequencies is prolonged, extending from March to December with peak in April-May and September. Fishes with mature, ripe and spent gonads were noticed from March to December. The relative condition factor(Kn) and gonadosomatic index (GSI) values ranged between 0.93-0.98 and 0.75-3.85 respectively, with peaks in March-May
Fishery of sciaenids with some observations on the biology and stock assessment of Johnieops sina (Cuvier, 1830) exploited along the Malabar coast
Sciaenids form an important demersal finfish resource exploited off Malabar coast. They are caught
by trawls, gillnets and ringseines and are landed throughout the year. The average annual catch was
2452 t during 2001-2008. The landings fluctuated but showed a decline. Though several species
supported the sciaenid fishery, Johnieops sina was the dominant species contributing more than 58%
to the catch. In the fishery, the length of J. sina ranged from 62 to 229 mm. The length at first maturity
was 114 mm for males and 122 mm for females. The spawning period is prolonged with two peaks,
one in September-November and another in February-April. The male тАУ female sex ratio was almost
equal in the catch. The length-weight relationship was estimated as W=0.000046658 L 2.8313. The
estimated asymptotic length (LтИЮ) and annual growth coefficient (K) of J. sina were 268 mm and 0.45,
respectively. The respective annual total, natural and fishing mortalities were 3.63, 1.10 and 2.31. The
spawning stock biomass is more than 30% of the stock at its unexploited level
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