Noronha returned to Funchal after college. On December 11, 1914, he was appointed librarian at the Municipal Library of Funchal. He became the Director in 1928, a position he held until his retirement in 1943. In addition to multiple specimens of fish caught while swordfishing, he collected sponges and
bryozoans, many of which were newly identified species. The best known case was the discovery, during dredging operations carried out in 1909 off the coast of the island of
Porto Santo, of an encrusting sponge with limestone and siliceous spicules, which was given the name Merlia normani. These dredging operations were done in conjunction with British spongiologist
Randolph Kirkpatrick, who published the description of
M. normani. Kirkpatrick dedicated a sponge genus to Noronha in 1908, that is now considered a taxonomic synonym of Merlia. His collaboration and correspondence with scientists of various nationalities resulted in his name being used for several taxa, including
Schizoporella noronhai (an abyssal bryozoan),
Pecten noronhai, and
Spondylus noronhai (fossil bivalve mollusks). In 1922, he led a scientific expedition to the
Savage Islands, which he had also visited in 1906 and 1909, along with Adão Nunes and Damião Peres. After difficulties with transport back to Madeira, the group stayed two months on the islands. The return to Funchal and the reason for the reception, were noted in the
Diário de Notícias do Funchal, of June 13, 1922. Meteorological statistics and the collected examples were sent to international experts. He also studied the deep-sea fish that were caught accidentally in the black scabbardfish fishery, subsequently describing two new species;
Diplogonurus maderensis, and a rare deep shark, which he dedicated to his friend Alberto Artur Sarmento with the binomial,
Squaliolus sarmenti. In addition to collaborating with Fernando Augusto da Silva and Carlos Azevedo de Meneses in the preparation of
Elucidário Madeirense (1922), he co-authored a paper entitled
Os Peixe dos Mares da Wood, with Sarmento in 1934. In 1948, he produced the second volume (dedicated to fish) of the work
Vertebrados da Madeira, edited by the General Board of the Autonomous District of Funchal. Noronha's actions were instrumental in the movement of the Funchal Municipal Library, which was originally housed in a small facility in the Paços do Concelho building. He also led the initiative to acquire a building that would allow for the creation of a museum to house the collections of natural history and other heritage belonging to the
Municipality of Funchal. In 1929, his work led to the founding of the Madeira Regional Museum and the acquisition of the São Pedro Palace (Funchal). He issued a postage stamp from Madeira, the proceeds from which were put toward the acquisition of the palace, and with the collaboration of
Günther E. Maul, the museum opened in 1933, giving rise to the current Museum of Natural History in Funchal. ==Personal life==