Mass. Gen. Laws ch. 130 § 13
The director, the deputy directors of enforcement, chiefs of enforcement, deputy chiefs of enforcement and all environmental police officers and deputy environmental police officers, or any member of the state police may request any person whom he has cause to believe is engaged in unlawfully fishing, or to be unlawfully in possession of fish, or to be in possession of fish unlawfully taken, to forthwith display for inspection all fish then in his possession, and may arrest without warrant a person refusing or failing to comply with such request.
Whoever, being in a boat in coastal waters throws or dumps overboard the contents of any pail, bag, barrel or other receptacle, or throws overboard any fish, after having been requested or signalled by any officer authorized to enforce this section to stand by for inspection shall be deemed to have violated this section.
Mass. Gen. Laws ch. 130, § 13