US FWS Henry O'Malley was an American fisheries science research vessel in commission from 1949 to 1951 in the fleet of the United States Department of the Interior's Fish and Wildlife Service.

She was the first U.S. fisheries science vessel to explore the central Pacific Ocean in search of commercially valuable populations of fish.

[2] In August 1947, the United States Congress authorized a new "Pacific Ocean Fishery Program" calling for the "investigation, exploration, and development of the high seas fisheries of the Territories and Island Possessions [of the United States] and intervening areas in the tropical and subtropical Pacific Ocean.

[12] During her visit to French Frigate Shoals, she also experimented while at anchor with the use of yellow lights to attract fish at night.

[11] Some of the bait was studied at the University of Hawaii,[11] while some was dumped into the waters of Pearl Harbor and found to be thriving there five days later.

[15] Her main objective was to collect bait at the French Frigate Shoals and then use it to fish for skipjack tuna off both the main Hawaiian Islands and the Northwestern Hawaiian Islands, with an overall goal of developing techniques for the use of United States West Coast-style fishing vessels and equipment in areas of the mid-Pacific Ocean not previously explored by fisheries scientists.

[16] During the voyage, she caught only 18 skipjack, her crew finding that her size and relative lack of maneuverability made it difficult to maintain contact with schools of fish.

[16] Plans for Henry O'Malley′s next cruise — her fourth in FWS service and third scientific cruise — called for her to conduct exploratory fishing off the Northwestern Hawaiian Islands, where she was to explore the French Frigate Shoals, Laysan Island, Pearl and Hermes Reef, and Midway Atoll for bait.

[19] However, what the November 1950 edition of the Fish and Wildlife Service publication Commercial Fisheries Review described as "operational difficulties" forced her to cut her cruise short, and she proceeded to Pearl Harbor, where she arrived on 30 August 1950, two weeks earlier than planned.

[20] Deeming her unseaworthy, and determining that additional repairs needed to make her ready for research operations were cost-prohibitive, the Fish and Wildlife Service decommissioned Henry O'Malley.

[1] In 1956, Edward P. Silva of San Diego, California, registered her under the same name and with the same tonnage, but with the radio call sign WD5312.

[2] In 1977, John L. Gomes of La Jolla, California,[2] registered her as a 325-GRT[2] fishing boat, again with the radio call sign WD5312, still named MV Santa Rosa,[21] and with her home port at San Diego.

[21] Santa Rosa dropped out of the registration rolls in 1984[21] and was listed as lying derelict at the Port of San Diego as of 1987.