Academic article

The effects of stocking density on gonad growth, survival and feed intake of adult green sea urchin (Strongylocentrotus droebachiensis)

Siikavuopio, Sten Ivar; Dale, Trine; Mortensen, Atle

Publication details

Journal: Aquaculture, vol. 262, p. 78–85, 2007

Publisher: Elsevier

International Standard Numbers:
Printed: 0044-8486
Electronic: 1873-5622

Open Access: none

Links:
DOI

In this study the effects of different stocking densities on survival, gonad growth and feed intake in adult green sea urchin
(Strongylocentrotus droebachiensis) were examined. Two size groups of sea urchins with respective initial mean weight of 45 g (S)
and 70 g (L) were used. The experiments were carried out in 755 l plastic tanks divided into chambers by vertical fibreglass
lamellae. In the two experiments stocking densities of 6, 12, 14 and 16 kg m−2 (Exp I) and 3, 6 and 8 kg m−2 (Exp II) were used.
Sea urchins reared individually in compartmentalised raceways were used as controls in both experiments. All groups were fed a
formulated moist feed ad libitum for 60 days at 8 °C (±0.5). Mortality was observed in all groups, except for the control group and
the lowest density group of large sea urchins (3 kg m−2, L). Both mortality and occurrence of injuries increased significantly with
increasing stocking density in both experiments and for both size groups. In the highest density groups mortality was 60% (L) and
80% (S). There was a significant increase in gonad index during the experimental period in both experiments. Increased stocking
density had a significantly negative effect on gonad growth in both size groups while feed intake was unaffected. The results show
that adult S. droebachiensis can maintain high survival rate and high gonad growth at stocking densities up 6 kg m−2 in holding
facilities of the design used in the present study.
© 2006 Elsevier B.V. All rights reserved.In this study the effects of different stocking densities on survival, gonad growth and feed intake in adult green sea urchin
(Strongylocentrotus droebachiensis) were examined. Two size groups of sea urchins with respective initial mean weight of 45 g (S)
and 70 g (L) were used. The experiments were carried out in 755 l plastic tanks divided into chambers by vertical fibreglass
lamellae. In the two experiments stocking densities of 6, 12, 14 and 16 kg m−2 (Exp I) and 3, 6 and 8 kg m−2 (Exp II) were used.
Sea urchins reared individually in compartmentalised raceways were used as controls in both experiments. All groups were fed a
formulated moist feed ad libitum for 60 days at 8 °C (±0.5). Mortality was observed in all groups, except for the control group and
the lowest density group of large sea urchins (3 kg m−2, L). Both mortality and occurrence of injuries increased significantly with
increasing stocking density in both experiments and for both size groups. In the highest density groups mortality was 60% (L) and
80% (S). There was a significant increase in gonad index during the experimental period in both experiments. Increased stocking
density had a significantly negative effect on gonad growth in both size groups while feed intake was unaffected. The results show
that adult S. droebachiensis can maintain high survival rate and high gonad growth at stocking densities up 6 kg m−2 in holding
facilities of the design used in the present study.
© 2006 Elsevier B.V. All rights reserved.