Original paper
Reproduction and condition of unionid mussels in the Vantaa River, South Finland
Pekkarinen, M.
Archiv für Hydrobiologie Volume 127 Number 3 (1993), p. 357 - 375
51 references
published: Jun 9, 1993
DOI: 10.1127/archiv-hydrobiol/127/1993/357
ArtNo. ESP141012703007, Price: 29.00 €
Abstract
Gravidity, seasonal courses of condition indices and health were studied in Anodonta anatina (L.), Pseudanodonta complanata (Rossm.), Unio pictorum (L.) and U. tumidus Philipsson. Notes on U. crassus Philipsson are also included. Females of A. anatina were gravid (bearing embryos or glochidia) from July to April or May. Gravid U. pictorum and U. tumidus were encountered from April to July and two gravid U. crassus - in June. The non-gravid interval of P. complanata in June was very short. A. anatina matured fairly early, the youngest gravid females being 1+ year old. The marsupial gills of gravid mussels were not always full. All species fattened in proportion to shell volume in spring and early summer when water temperature was rising. This fattening partially preceded the rapid shell growth. Gravid females of A. anatina were fatter than males, but during the non-gravid interval of females and the normal spermatogenesis of males, males tended to be fatter. Interannual differences were noticed in the condition and gravidity period of the Vantaa mussels. All species included occasional hermaphrodites. Developing mites were common in P. complanata and the Unio spp. and less common in A. anatina. Seasonal prevalences of bucephalid trematode sporocysts and a pustular disease in A. anatina, with notes on some other diseases in the Vantaa mussels are reported.
Keywords
mussels • gravidity • females • males • bucephalid • disease • hermaphrodites • Vantaa River • Finland