A vein of shells

I don't know why, but the sandy area around Langosta Beach and Langosta estuary has areas where there are lots of shells, and other areas where there is sand, and only a few shells.  This vein of shells and coral was in the shallows of near the mouth of the estuary.

The crabs must be adapted to the variable salt content of water, as the tide brings salt water in, but the estuary would also allow fresh water to flow out to the sea.

This week we have photos highlighting the wildlife of Tanzania, Africa posted on our Viva la Voyage travel photo site.