Morphometric characteristic of gonadal cycle of mussel Dreissena polymorpha (Pallas, 1771)

Eršek, Marija (2011) Morphometric characteristic of gonadal cycle of mussel Dreissena polymorpha (Pallas, 1771). Diploma thesis, Faculty of Science > Department of Biology.

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Abstract

The research of mussel Dreissena polymorpha was conducted during one year at hydroelectric power plant reservoir Dubrava. Developmental stages of gonads were determined by histological techniques. Gonad volume, volume of the visceral sac, digestive gland, digestive tract and volume of other tissues of visceral mass were calculated using computer program LUCIA G 4.81, as well as the corresponding indices. The gender ratio was approximately 1:1. Gametogenesis begins in autumn. The spawning occurs during late spring and summer. Most individual complete the reproductive cycle in July. The highest average value of sexual maturity index were determinated in July, and lowest in August. The highest value of gonad volume and gonad index observed in males were in June, and in females in April. The lowest values were recorded in August. Differences between two sexes ocurred in the timing of the resting phase and gametogenesis, while during the spawning males and females were synchronized. The digestive gland index, digestive tract index and other tissues of visceral sac index were the highest when the value of volume and gonad index were the lowest. The presence of endoparasites trematoda was identified, which negatively affects the development of the gonads.

Item Type: Thesis (Diploma thesis)
Keywords: reproductive cycle, gonad stages, gonad volume, gonad index, trematoda
Supervisor: Lajtner, Jasna
Co-supervisor: Gregorović, Gordana
Date: 2011
Number of Pages: 44
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Silvana Šehić
Date Deposited: 25 Sep 2014 10:33
Last Modified: 25 Sep 2014 10:33
URI: http://digre.pmf.unizg.hr/id/eprint/2818

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