"on the others, he had a big blue runner and a yellow jack"
Blue runner
Public DomainBlue runner
Yellow jack (a reference to the fish, not the guy in the trunks)
Public DomainYellow jack (a reference to the fish, not the gentleman in the trunks)
The blue runner is a common medium-sized (35-70 cm or 14-28 inches) marine fish.

The yellow jack is a somewhat larger marine fish, averaging in length from about 45 cm to 1 m long (18-39.5 inches).