Crossword Genius

Danger for surfers? Gather risk has to be reviewed (5,5)

Ross

I believe the answer is:

tiger shark

I'm a little stuck... Click here to teach me more about this clue!

'danger' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.

'surfers? gather risk has to be reviewed' is the wordplay.
'gather risk' can be anagrammed to 'TIGER SHARK'.
However, I'm unsure how this is indicated.

'for' is the link.

Can you help me to learn more?

(Other definitions for tiger shark that I've seen before include "Large aggressive fish" , "big fish" .)

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