Distribution and production of three Hydrobia species (Gastropoda: Hydrobiidae) in a shallow coastal lagoon in the Bay of Cádiz, Spain
Drake, P.; Arias, A.M. (1995). Distribution and production of three Hydrobia species (Gastropoda: Hydrobiidae) in a shallow coastal lagoon in the Bay of Cádiz, Spain. J. Moll. Stud. 61(28): 185-196. http://dx.doi.org/10.1093/mollus/61.2.185
In: Journal of Molluscan Studies. Oxford University Press: Reading. ISSN 0260-1230; e-ISSN 1464-3766, more
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| Keywords |
Abundance
Taxa > Species
Hydrobia W. Hartmann, 1821 [WoRMS]; Hydrobia minoricensis
ANE, Spain, Andalusia, Cadiz Bay [Marine Regions]
Marine/Coastal |
| Abstract |
The abundance, life span, growth and production of the mud snails Hydrobia minoricensis, H. ulvae and H. ventrosa in a semi-natural lagoon system were studied by taking monthly samples at three sites during 1991 and 1992. The most abundant species, H. minoricensis occurred at mean densities of 12834 to 26264 snails m-2 (10.7 to 25.8g dry weigh m-2), depending on the site. The least abundant species, H. ulvae, occurred at mean densities of 185 to 353 snails m-2 (3.2 to 2.2g dry weight m-2). The numerical abundance and biomass of the three Hydrobia species were positively related to the biomass of benthic macroalgae (P<0.01). Although H. ulvae egg capsules were recorded throughout the year, newly hatched snailsof this species were not observed, in contrast to the other two species. The early spring and summer cohorts of H. minoricensis and H. ventrosa seemed to be the most numerous. The average life spans of these two species were estimated to be about 18 and 13 months respectively. Annual production estimates for the whole lagoon system were 29.0 (6.3), 5.5 (0.8) and 5.2 (1.0)g dry weight (ash-free dry weight) m-2 yr-1 for H. minoricensis, H. ulvae and H. ventrosa respectively. The annual P/B ratio was about 2 for H. minoricensis and H. ventrosa. |
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