Publication Date:
2021-05-19
Description:
The project of Age, growth, feeding regime and fecundity of Kutum (Rutilus frisii Kutum) survey started in
south of the Caspian Sea from 2006 to 2007. The aim of project was related to determination of length maturity
(Lm50%), identification of feeding animals, and investigation some of biological aspects uncluded in sex ratio, growth and age structure in southern of the Caspian Sea. Total 2706 specimens of Kutum were surveyed. The
age structure of Kutum has nine age groups that included in 1, 2, 3, 4, 5, 6, 7, 8, and 9 years. The result showed
that maximum frequency was about 39.3 % and were belong to 4 years and minimum frequency which was
about o.1 % were belong to 9 years. The maximum and minimum fork length and weight were 58 and 21cm with mean (±SD) 38.4 (± 6.4) cm; 2450
and 104g with mean (±SD) 784.2 (± 383.30) g , respectively. There are significant different between fork length
and weight in male and female of Kutum at difference months (ANOVA, P〈0.05). The sex ratio of males to
female was 0.65: 1 (males: females). The least and high condition factor was 1.5 in January and 2.17 in October, respectively. Length maturity (Lm50%) was 39.07cm. Minimum and maximum absolute fecundity was varied from 15713 to
130737 eggs with mean (±SD) 69961.7 (± 3836.4). Significant different was between absolute fecundity with
fork length and weight (p〈0.05).
Gonadosomatic index (GSI) mean for females were 2.5±0.2 (autumn) and 17± 0.2 (spring); 1.2± 0.1 (autumn)
and 4.1± 0.2 (spring) for males, respectively wich coincided to spawning period. The highest feeding intensity
(Gastrosomatic index) for females was 313.9 ± 65.9 in October and 119.4 ±59.2 in March; 350.7 ±103.7 in
October and 144.1±85.04 in March for males, respectively. There are significant different between GSI with
male anfemale in difference months (ANOVA, p〈0.05). The Bertalanffy growth equation for all populations of
Kutum was L (t) = 63.92[1-e ^0.19 (t (-1.00)
]. Main prey mature of Kutum was Cerastoderma lamarki; Gastropoda and Balanus were subordinate, and Crab, Hypanis, Fish (Neogobous sp.) Algae, egg, and scale were random preys. Planktone groups comprise to
Exuviaella, Nitzchia, Osillatoria, Synedra, Nematoda, Navicolla, Diatoma, Rholcosphenia were preys juvenile of
Kutum. Based on ISI (Important species index), Cerastoderma lamarki and Balanus were dominant species in
feeding of Kutum. As a result, growth, fecundity and length maturity of Kutum declined which may due to loss natural breeding
area, overfishing (overlapping between fishing and spawning period) and artificial breeding that commenced
since 1982. Hopefully, this information can be used in fisheries management.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Age
;
Growth
;
Feeding
;
Regime
;
Reproduction
;
Sexual maturity
;
Rutilus frisii kutum
;
Coastal waters
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
58pp.
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