These straps are used to bind the batim to one's arm/hand (Tefillin shel Yad) and to one's head (Tefillin shel Rosh) in obedience to Deuteronomy 6:8 (And thou shalt bind them for a sign upon thine hand, and they shall be as frontlets between thine eyes).
Given that a single mangrove area can produce as much as four tons of detritus per year, the mud crab's work as a decomposer is a primary part of the detritus-based food ecology that supports fisheries populations.
Decomposers and scavengers break down dead plants and animals. They also break down the waste (poop) of other organisms. Decomposers are very important for any ecosystem. If they weren't in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up.