Bonnelly was born on 10 September 1931 in Santiago de los Caballeros, Dominican Republic. Because she wanted to study marine biology and there were no schools teaching biology in the Dominican Republic, she pursued her university studies in New York. In 1953, she enrolled at Columbia University, graduating with a BS in marine biology in 1956. She went on to attain a master's degree from New York University in 1961. After completion of her schooling, Bonnelly began her first job at the New York Aquarium as a research assistant to Ross Nigrelli. In 1962, she returned to the Dominican Republic and began teaching at the Universidad Autónoma de Santo Domingo, founding the first institution for the study of biology in the country. In 1966, she founded the Institute of Marine Biology, which later became the Research Center of Marine Biology , at which she taught from 1967 to 1986 and then until 1992 served as the coordinator of graduate studies. In 1974, Bonnelly founded the Academy of Sciences of the Dominican Republic and began publishing works which became widely influential for those managing and concerned with conservation of marine resources. In 1986, she was instrumental in the creation of the first protected area for the humpback whale, originally called the Humpback Whale Sanctuary on the Silver Bank, the National Science Prize from the Academy of Sciences of the Dominican Republic, and was inducted into the Global 500Roll of Honour by the United Nations Environment Programme in 1987. She became a Professor Meritorious at in 1990 and in 1991 she created the Dominican Foundation for Marine Research, , an institution which coordinates the marine management plan, studies marine life and the coral reef, and manages the Marine Mammal Sanctuary. That same year, Bonnelly joined the Organization for Women in Science for the Developing World and served in the First General Assembly. She continued publishing and her works have been utilized for influencing marine and coastal Environmental Law. Bonnelly was made an academic laureate of the Academy of Sciences in 2007, received a National Ecology Award from the Fundación Corripio in 2008, and was awarded the Marie Curie Medal from UNESCO in 2009. In 2010, the Society for the Conservation of Biology of Victoria, British Columbia, Canada, honored her with a Distinguished Service Award in Biology and in 2011, the Government of the Dominican Republic granted her the Order of Merit of Duarte, Sánchez and Mella. In 2013, she was recognized by the BBC as one of the ten most important women scientists in Latin America.
