(a) No person who is using a trawl for the purpose of taking shrimp may retain a redfish, speckled sea trout, or lightning whelk, also known as Busycon perversum pulleyi, caught in the trawl.
(b) No person may retain a redfish, speckled sea trout, or lightning whelk if the person is on board a boat licensed under this chapter and if there is a shrimp trawl on board the boat.