When my mom was assigned before as a School Principal in 3 small islands in our town usually she comes home with nearly 20kilos of seashells that were given by the local residents. Means of livelihood there is fishing and sometimes if low tide they used to collect seashells, sea weeds and octopus.
For locals its like hobby for them. Seashells are rich in iodine and really nice to sip the seashells soup while its hot.
Photo from Shur Lee's Album