The impact of climate change on the ecology, reproduction and distribution of marine mammals and the possible legislation, conservation and management approaches to protect these marine mammal species: A systematic review

This paper aims to review and evaluate published literature on the impact of climate change on marine mammals. A systematic method was utilized to access research works of literature on “Impact of Climate Change on Marine Mammals”. A total of eighty-two (82) research papers published between the years 1976 to 2024 were accumulated and used for this review. A subjective approach was used to select the topics: impact of climate change and marine mammals. In this paper, nine (9) direct and indirect effects of climate change and environmental factors affecting marine mammals were assessed in this paper. Further, six (6) detrimental impacts of climate change on marine mammals were evaluated and presented. In addition, an integrated checklist of one hundred twenty-seven (127) marine mammal species were presented along with their current IUCN Red List status categories. Subsequently, a total of eighty-three (83) cetaceans (whales, dolphins and porpoises), thirty-four (34) pinnipeds (seals, sea lions and walruses), six (6) sirenians (manatees and dugongs) and four (4) fissipeds (polar bears and sea otters) were presented on the integrated checklist. In addition, this paper assessed some marine mammal species that are endangered and threatened with extinction such as Monachus monachus and Phocoena sinus. Legislation, conservation and implications for the management and preservation to address marine mammals and combat the effect of climate change was also presented in this review. The published works of literature established that the global marine mammal population dynamics, ecology, reproduction, abundance and distribution are all affected by the threats of climate change. The availability of prey impacts the distribution, abundance and movement of marine mammals as well as their community structure, vulnerability to toxins and disease, success of their reproduction, and, ultimately, their survival. Additionally, marine mammals are particularly vulnerable to the possible effects and repercussions of changes in salinity, pH, and CO2. This review highlights that more extensive studies on the impact of climate change on marine mammals should be done in neotropical countries since there are gaps of such information on research and published data in these biodiversity-rich regions.