I've noticed two things:

1) Beaches I visit regularly are never the same - there can be huge difference in the number, diversity, identity and condition of the shells in it. Some days the beach is positively covered in fresh shells, others there seems to be nothing. Some species may be very common a given day, while absent in others. Some days it's pretty much just bivalves, some days gastropods are abundant. I am not sure what drives this variation (tides, storms? I can't find a logical pattern yet).

2) My tendency had been to pay more attention to the less common species in each visit, which had the effect that for some rarer species I had quite a few observations, whereas for some common ones I had very few (i.e. there is a bias in my observation list towards the rarer species in each visit).

So I have started a habit of whenever I visit a beach, to try to find as many species of marine molluscs as possible, and to make at least one observation for each. Here I list the corresponding "bio-blitzes" (that I will update over time).

24-27/07/2021 - Praia da Galé, Tróia, Portugal - observations

03/08/2021 - Plage de Ramonette, Belle-Ile-en-Mer, Bretagne, France - observations

04/08/2021 - Plage de Port Parnec, Hoedic, Bretagne, France - observations

06/08/2021 - Plage des Grands Sables (western half), Belle-Ile-en-Mer, Bretagne, France - observations

07/08/2021 - Plage de Bordardoue, Belle-Ile-en-Mer, Bretagne, France - observations

08/08/2021 - Plage de Port Jean, Belle-Ile-en-Mer, Bretagne, France - observations

09/08/2021 - Plage de Port Guen, Belle-Ile-en-Mer, Bretagne, France - observations

11/08/2021 - Plage de Donnant, Belle-Ile-en-Mer, Bretagne, France - observations

22/08/2021 - Plage du Petit Travers, Occitanie, France - observations

12/09/2021 - Plage du Petit Travers, Occitanie, France - observations


  • The list of observations/species in each bio-blitz may still grow over time, as in some cases I am still working on entering/identifying the shells I collected.
  • Effort varies, but typically it is proportional to the abundance and diversity of shells (I stop if after a while I can't see anything new).
Publicado el agosto 23, 2021 01:05 TARDE por anasacuta anasacuta


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