The reproductive cycle of the zebra mussel Dreissena polymorpha (Pallas, 1771) in the hydroaccumulation Čakovec

Penić, Tina (2010) The reproductive cycle of the zebra mussel Dreissena polymorpha (Pallas, 1771) in the hydroaccumulation Čakovec. Diploma thesis, Faculty of Science > Department of Biology.

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Abstract

Field research was conducted from May to October 2006. Using conventional histological examination developmental stages of gonads were studied. Gonad volume, volume of the digestive gland and volume of other tissues of visceral mass were measured with computerized image analyses LUCIA G 4.81. The results showed that in the studied hydroaccumulation sex ratio was 1:1. Although the reproductive cycle of mussels generally synchronized, all the developmental stages of gonads were first observed in females. In May, the gonads of most individuals were at the prespawning stage. The spawning occurred in June and early July, which was confirmed by the increase in number of individuals which were at the postspawning stage. The stage of inactive gonads was observed in a small number of females in August. The process of new gametogenesis started in September and continued during October. The highest volume of gonads and gonad indices were determined in June, and the lowest in September when the most of the individuals were at the inactive stage of gonads. In contrast to the gonads, the values of volume and digestive gland indices were lowest in June and highest in September. During the research the presence of endoparasites trematoda was also identified.

Item Type: Thesis (Diploma thesis)
Keywords: Dreissena polymorpha, reproductive cycle, gonad stages, gonad volume, gonad index, trematoda
Supervisor: Lajtner, Jasna
Date: 2010
Number of Pages: 46
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Silvana Šehić
Date Deposited: 08 Sep 2014 11:16
Last Modified: 08 Sep 2014 11:16
URI: http://digre.pmf.unizg.hr/id/eprint/2658

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