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Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae) in Eastern Arabian Sea

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Title Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis
(Sepioidea: Sepiidae) in Eastern Arabian Sea
Not Available
 
Creator Bhat,S Uma
Mohamed,K S
Sasikumar,Geetha
 
Subject cuttlefish
Sepia pharaonis
growth
length-weight relationship
age
Eastern Arabian Sea
 
Description Not Available
Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region.
Despite its commercial significance, only few information on natural populations is available. This study was
aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment
and inter-cohort growth patterns of S. pharaonis population (Clade C), distributed along the Eastern Arabian Sea
(South-West coast of India). For this, the Dorsal Mantle Length (DML) and weight of cuttlefishes was obtained
from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight
methods such as von Bertalanffy. A total of 12 454 cuttlefishes, ranging in length from four to 41cm were analyzed.
Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease
in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modalprogression
analysis using the Bhattacharya’s method for the estimation of growth. The estimated parameters
L∞ and K in von Bertalanffy Growth Function (VBGF) were used to model growth curves in length for the
cohorts. The first cohort, (post-monsoon cohort) which supports the major fishery, was composed of mediumsized,
fast growing individuals, whereas the second cohort (pre-monsoon cohort), comprised of slow growing
and large-sized individuals. There were differential growth characteristics between the sexes and the life span
was estimated at less than 2.3years for males and 2.1years for females. Negative allometric growth in weight
(W) with length (L) was observed for males (W=0.33069.L2.5389) and females (W=0.32542.L2.6057). The females
were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate
lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates
of 1.67-13.02kg/h were observed in comparison with 0.03-0.85kg/h in December-April. Seasonal catch rates
indicated a migratory life cycle of S. pharaonis between offshore and inshore coastal zones
Not Available
 
Date 2021-09-16T09:17:59Z
2021-09-16T09:17:59Z
2013
 
Type Article
 
Identifier Not Available
Not Available
http://krishi.icar.gov.in/jspui/handle/123456789/63181
 
Language English
 
Relation Not Available