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Identifier

000412892

Title

Εκτροφή αχινού του είδους Paracentrotus lividus (Echinodermata, Echinoidea), με τεχνητά σιτηρέσια

Alternative Title

Culture of sea urchin of the species Paracentrotus lividus (Echinodermata, Echinoidea), with artificial feeds

Author

Ταρίφα, Γεωργία Α.

Thesis advisor

Κεντούρη, Μαρουδιώ

Reviewer

Στεριώτη, Ασπασία
Χατζηφώτης, Σταύρος

Abstract

The sea urchin Paracentrotus lividus (Lamarck 1816) is of particular economic interest due to the high commercial and nutritional value of its gonads which are widely consumed. Increased demand has led to overfishing of the species and the collapse of natural stocks in areas where in was in abundance (e.g. France). Thus, the need for culture methods with the use of appropriate food was emerged. In the present study, three artificial handmade feeds were tested in rearing urchins in forage water: 1) 44.7% wheat - 44.7% fish meal with the addition of β-carotene (M1), 2) 89.4% fishmeal (A), 3) 68% barley - 22% krill (M2). In the course of the culturing experiment, were manifested a disease with characteristic wounds in the body of the urchins, a marked degradation of skeletal elements of the urchins and high mortality. The design of the experiment was modified: culturing was repeated in two different water qualities, in seawater (salinity 36 ‰, pH ~7,8) and in forage water (salinity 36 ‰, pH 8,1), and were tested the feeds which presented the highest (M1) and the lowest mortality (A). Under these conditions, gonadal growth had been satisfactory over a short period of time, compared to urchins of the natural environment, but not their color as well, despite the enrichment of a feed with β-carotene. Therefore, extraction of carotenoids from the gonads and from food pellets was performed and the concentration of (total) carotenoids was measured. It turned out that their amount declined over time during the course of the experiment probably due to a deficiency in either the amount of β-carotene added to the M1 food mix or the time necessary so as the β-carotene the urchins received from their diet, to be “expressed” in color. An attempt to identify the pathogenic micro-organisms that could be responsible for the onset of the disease was also made, using microbiological and molecular methods, with the results of the latter being in progress. Finally, the degradation of the skeletal elements of the urchins that were cultured in forage water which was manifested by the loss of their thorns, was attempted to be associated with the lower pH which characterizes the forage water and/or based on the total water “quality”. This thesis is developed in 4 sections, which concern: (a) the results of culture in drilling water and seawater (Section 1 and 2), (b) the effect of forage water on the survival and development of the urchins (Section 3), and (c) the pathology of the sea urchins (Section 4).

Language

Greek

Subject

Carotenoids

Forage water

Gonad development

Pathology

Ανάπτυξη γονάδων

Αχινός

Καροτενοειδή

Νερό γεώτρησης

Παθολογία