Growth and reproduction of the bivalve Spisula subtruncata (da Costa) in Dutch coastal waters
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
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| Keywords |
Age determination
Population functions > Growth
Reproduction
Water bodies > Coastal waters
Spisula subtruncata (da Costa, 1778) [WoRMS]
ANE, Netherlands, Dutch Coast [Marine Regions]
Marine/Coastal |
| Author keywords |
growth; reproductive investment; age determination; oocyte diameter;Spisula subtruncata; Dutch coastal waters |
| Authors | | Top |
- Cardoso, J.F.M.F.
- Witte, J. IJ.
- van der Veer, H.W.
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| Abstract |
The bivalve Spisula subtruncata is usually abundant in shallow coastal waters along the Dutch coast. However, its biomass has been decreasing since 1995. In order to assess whether reproductive failure may be the cause of the observed decline over the last decades, the energy investment in reproduction of a population of S. subtruncata from central Dutch coastal waters was studied. The population studied consisted of individuals of up to four years old. Shell length reached maximum values of around 32 mm and individual total body, somatic and gonadal ash-free dry mass reached maximum values of about 278 mg AFDM, 252 mg AFDM and 76 mg AFDM, respectively. A clear seasonal cycle in somatic and gonadal mass was observed. Somatic and gonadal mass indices increased in early spring and reached maximum values during summer, followed by a decrease to minimum values at the beginning of the following year. Spawning was in June-July and settlement of spat seems to have occurred in July-August. Mean oocyte diameter was 57.43 ± 0.03 μm, corresponding to a volume of 98972 µm3. These results suggested that reproductive failure was not the cause of the current population decline. Most likely, unsuccessful settlement of spat and/or severe predation during the first months of life were responsible for the observed patterns. |
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