Biological and ecological characteristics of whiting (Merlangius merlangus, L.) in the Adriatic Sea

Milić, Danijela (2012) Biological and ecological characteristics of whiting (Merlangius merlangus, L.) in the Adriatic Sea . Doctoral thesis, Faculty of Science > Department of Geology.

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Abstract

In the present study, a total of 1.439 specimens of whiting, Merlangius merlangus (Linneaus, 1758) were collected in the eastern part of the Northern Adriatic, ranging in total length from 15,2 to 35,0 cm (21,37±3,02 cm) and in weight from 21,68 to 383,80 g (74,84±40,15 g). Female to male ratio was 1,00:1,02 and all whiting longer than 26,0 cm were female. The length-weight relationship showed positive allometric growth (b=3,184) and estimated condition index was 0,712. There were statistically significant differences in mean values of 15 morphometric relationships between females and males. Meristic and morphological characters of whiting, as well as phylogenetic analysis, showed that the population in the Adriatic is genetically isolated from the whiting populations in the Black Sea and Atlantic. The highest feeding intensity of the whiting was recorded during winter and dominant food components were fish and decapods. Age of the fish was determined by otolith reading. The growth of whiting was described using the von Bertalanffy growth model (L∞=39,1 cm; K=0,232; t0=-0,52; R2=0,790) and the sample was dominated by 1 and 2 year specimens. Maximum age for females and males was 4 and 3 years, respectively, and the growth of females and males was significantly different. Fecundity of females was relatively high and spawning season in the Adriatic takes place between December and February. The highest gonadosomatic index values were found in December. Fishing mortality was much higher than the observed natural mortality. The data collected during expeditions MEDITS and AdriaMed revealed that whiting was mostly distributed in the Northern Adriatic and along the Italian coast, where depth doesn't exceed 100m and salinity and temperature values are lower. Between 1994 and 2009 a trend of higher recruitment was observed in the Italian part of the Adriatic and in the extraterritorial Sea.

Item Type: Thesis (Doctoral thesis)
Keywords: Adriatic, age, biometry, diet, distribution, growth, M. merlangus, mortality, reproduction
Supervisor: Kraljević, Miro
Date: 2012
Number of Pages: 128
Subjects: NATURAL SCIENCES > Geology
NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science
Divisions: Faculty of Science > Department of Geology
Depositing User: Sonja Borak
Date Deposited: 29 Jan 2014 13:00
Last Modified: 29 Jan 2014 13:00
URI: http://digre.pmf.unizg.hr/id/eprint/286

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