The Ninth Circuit rejected a challenge to California's Shark Fin Law, Cal. Fish & Game Code § 2021(b) which makes it "unlawful for any person to possess, sell, offer for sale, trade, or distribute a shark fin" in the state. The case is Chinatown Neighborhood Ass'n v. Harris and the opinion can be found here.
Shark finning is a practice of harvesting shark fins to make shark fin soup. The rest of the living shark is discarded.
The practice was prohibited by Congress in 2000. California outlawed possession of fins without the shark carcass in 1995, then in 2011 criminalized the possession of detached shark fins in the California Shark Fin Law.
Several trade associations filed a federal challenge to the Shark Fin Law asserting that California's law was preempted by federal fisheries law.
The Ninth Circuit found that the federal fisheries law, the Magnuson-Stevens Fishery Conservation and Management Act, 16 U.S.C.§§ 1801-1884 did not preempt California's Shark Fin Law. The Court similarly rejected a dormant commerce clause challenge to the law.
Fisheries laws are a complex web of federal and state laws and regulations. For sure, the States have the power to regulate fisheries within their waters, typically seaward of the 3 nautical mile line from the baseline. Similarly, States can regulate fish LANDED in their ports.
Federal law can and does preempt state law under the Supremacy Clause of the Constitution. Federal fisheries laws does not preempt California's Shark Fin Law. So says the Ninth Circuit.