A pirate? No: a coho salmon breeding strategy. In coho society, the hooknoses are large, fierce salmon that fight each other for access to females, while jacks are small, fast salmon that snog the females while the hooknoses are accomplishing said fighting.
Interestingly, female salmon prefer the jacks, spending more time preparing their nests and ovipositing (dropping eggs) when in jacks’ presence. But in order to avoid mating with winning hooknoses, they have to spend energy escaping. And so both coercion (hooknose) and cooperation (jack) work for male salmon.