One of the most tenacious and dangerous legends about the shark is that he has poor eyesight.

Brave : ready to face and endure danger or pain; showing courage.
Strong : having the power to move heavy weights or perform other physically demanding tasks.
Heroic : having the characteristics of a hero or heroine; admirably brave or determined.
Foolish : lacking good sense or judgement; unwise.
Tenacious : tending to keep a firm hold of something; clinging or adhering closely.

Synonym of Tenacious is Strong