Croaker

Cynoscion regalis, the weakfish, is a marine ray-finned fish of the family Sciaenidae, the drums and croakers.

A medium-large, slender, marine fish, it is found along the east coast of North America. The head and back of this fish are dark brown in color with a greenish tinge. The sides have a faint silvery hue with dusky specks, and the belly is white. The origin of its name is based on the weakness of the mouth muscles, which often cause a hook to tear free, allowing the fish to escape. The weakfish grows to 1 m (3.3 ft) in length and 9 kg (20 lb) in weight. It is found along the eastern coast of North America from Nova Scotia, Canada to northern Florida, where it is fished both commercially and recreationally.

This species has become established in the Gulf of Cadiz in the eastern Atlantic. This introduced population was first noted in 2011 when a specimen misidentified as Cynoscion nebulosus was taken and there is now a well established population.

The weakfish is the state fish of Delaware.

Behaviour

Cynoscion regalis are schooling fish, meaning that they spend a large majority of their time swimming together either trying to evade larger predators, or trying to feed more efficiently on prey. Studies done by the university of Michigan state that these schooling patterns tend to become much tighter in signs of stress as they state, "weakfish have an acute chemosensory response mechanism. In times of stress, weakfish gather into tighter schools, this was seen in lab studies when higher temperatures were used. The weakfish under these conditions showed a 35% decrease in their distance to the other fish in the school. Also the frequency of school formation increased in response to stress" (Gillum). Weakfish school closer together when in situations of high stress in this study done by the university of Michigan. Theorizing that they use schooling as a form of protection.