Degas worked around animal shelter during period of decline (8)

'during period of decline' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'degas worked around animal shelter' is the wordplay.
'worked' indicates an anagram.
'around' means one lot of letters goes inside another.
'animal shelter' becomes 'ark' (ship which shelters animals in the Bible).
'degas' with letters rearranged gives 'dages'.
'dages' going around 'ark' is 'DARKAGES'.

Can you help me to learn more?