skip·jack 
(skĭpjăk′)
(skĭpjăk′)n. pl. skipjack or skip·jacks
1. A skipjack tuna.
2. Any of various other fishes, such as the bluefish, that habitually leap out of the water.
3. pl. skip·jacks A fishing sloop having a bottom shaped like a flat V and vertical sides.
[SKIP1 (in reference to its leaping behavior) + JACK, fellow.]