Invasive species of molluscs in the Adriatic sea

Drnić, Martina (2016) Invasive species of molluscs in the Adriatic sea. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

Invasive species are species that do not naturally live in some area but they have entered with the intentional or accidental introduction, and their settlement and expansion have a negative impact primarily on biodiversity. In the Adriatic, there are a few species of invasive molluscs, and in this work two species of snails are introduced, Rapana venosa and Crepidula fornicata, and two species of shellfish, Crassostrea gigas and Mya arenaria. Rapana venosa is a big Asian snail, extremely flexible and has a high ecological fitness. It was found in the northern Adriatic in 1973. Because of its greed it is considered as one of the most undesirable invasive species worldwide and can affect the natural and cultivated populations of oysters, mussels and other molluscs. Crepidula fornicata is a North American species that is widely spread in the northern Adriatic. In Europe it was introduced in the 1970s, and in the Adriatic it appeared a few years later. The pest is on the oysters and mussels. Crassostrea gigas is an Asian species of shellfish which is highly resistant to environmental stress. It is recorded in the Adriatic Sea, and once established population leads to changes in habitat, causing eutrophication, as well as problems in shellfish farming. Due to the large environmental impact, this species was declared as one of the 100 most invasive alien species in Europe. Mya arenaria is a widely spread species because of its adaptability to different environments. It originates from North America. It is the oldest documented species that has been introduced into European waters and it appeared in the Mediterranean in 1976. It is compeeting with other species, causing abiotic changes and using resources. Due to its size, population size, long life and ease of recognition is used as the indicator species and species suitable for monitoring. C. gigas and M. arenaria were introduced and spread via ballast water and fouling of ships, and in addition, species R. venosa and C. fornicata enter and spread with variety of vectors and random transfers in aquaculture (spat of oysters). Scientists found out that C. gigas had a positive effect on other invasive species like snails C. fornicata and R. venosa.

Item Type: Thesis (Bachelor's thesis)
Supervisor: Lajtner, Jasna
Co-supervisor: Lajtner, Jasna
Date: 2016
Number of Pages: 29
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Grozdana Sirotic
Date Deposited: 26 Oct 2016 08:40
Last Modified: 26 Oct 2016 08:40
URI: http://digre.pmf.unizg.hr/id/eprint/5235

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