12 Days of Terror (2004) on Netflix

Plot summary

July 1916 brings a polio epidemic, record heat and a war in Europe, and crowds fill the New Jersey shore. Lifeguard Alex watches one beach while his friend Stanley and his former girlfriend Alice plan their wedding. A swimmer is attacked; Alex and other lifeguards pull him out, and he dies. Alex is sure a shark did it, but he did not see the animal clearly and his account is dismissed. Mayor Perillo refuses to close the beaches without expert confirmation. Captain Cap, who has hunted sharks for years, believes Alex and offers him work setting steel nets. President Wilson speaks about safety, and Commissioner Meel promises Alex there will be no second attack. Word of the attacks reaches Michael Schleisser, a wild animal wrangler in New York City, and ichthyologist Dr. John Nichols begins investigating.