Ask the meaning of a sentence .

[nancycumt]

i read a piece of picture news in the China Daily .I cannot understand it .
that is :A government official shows a bag of confiscated blood clams in this file photo.
what's the meaning of "blood" and the whole sentence?

Would you like to help me?
Thank you !

[Mister Micawber]

.
Blood clams are a kind of edible bivalve mollusc (Noetia ponderosa or Anadara ovalis). They are a delicacy, but dangerously poisonous in some circumstances, so their harvest is probably prohibited.

The government worker is exhibiting a bag of these clams, which they have taken from someone who was illegally collecting them. ('file photo' means that the photograph is an old one, taken before the news occurred)
.