Long-term strategies for studying rare species: results and lessons from a multi-species study of odontocetes around the main Hawaiian Islands This paper describes both our approach to studying rare species and provides findings from a long-term study of pygmy killer whales in Hawai‘i, including results from genetic analyses (of both stranded animals and biopsied free-ranging individuals), satellite tagging (both success and failures, including removal of tags by conspecifics), and photo-identification (including long-term re-sightings, movements among islands, and social network analyses). It shows that resident groups off O‘ahu and Hawai‘i Island share a common mitochondrial haplotype, and that mass strandings on Maui likely represent groups from an open-ocean population, among other things. Citation: Baird, R.W., S.D. Mahaffy, B. Hancock-Hanser, T. Cullins, K.L. West, M.A. Kratofil, D.M. Barrios, A.E. Harnish, P.C. Johnson. 2024. Long-term strategies for studying rare species: results and lessons from a multi-species study of odontocetes around the main Hawaiian Islands. Pacific Conservation Biology https://doi.org/10.1071/PC23027 Abstracts are included in both English and ʻŌlelo Hawaiʻi, below. For those who subscribe to Pacific Conservation Biology, the paper is available at https://www.publish.csiro.au/PC/PC23027 If you don’t subscribe and would like a pdf, let me know. Supplemental materials are available to all at https://www.publish.csiro.au/PC/acc/PC23027/PC23027_AC.pdf Robin Abstract Context. Funding agencies are often unlikely to fund research on rarely-encountered species and limited time is usually spent with such species when they are not the focus of research. Thus, knowledge of these species often lags behind their encounter rates. Aims. To gain information on rarely-encountered odontocetes in Hawai‘i while simultaneously studying common ones. Methods. During a long-term small-boat based study, we prioritized time spent with rarely-encountered species, collecting photos and biopsy samples, and satellite tagging. Sample sizes were augmented with photo contributions from members of the public and other researchers, and genetic samples from stranded animals and other researchers. Results from genetic and tag data analyses were interpreted in the context of social network placement and re-sighting histories. Key results. Pygmy killer whales (Feresa attenuata) represented <2% of odontocete sightings, and sighting rates varied by depth and among islands. Photo-ID shows that 318 of 443 identified individuals are linked by association in the main component of the social network. Movements among islands were limited, with individuals off O‘ahu and Hawai‘i exhibiting high site fidelity, although resident groups from each island share a common mitochondrial haplotype. Three groups involved in mass strandings in two different years were not linked to the main component of the social network, and did not share mitochondrial haplotypes with known resident groups. Conclusions. The approach of prioritizing rarely-encountered species for additional sampling is an effective way of learning more about poorly-known species. Implications. Such an approach may be critical for filling data gaps for populations potentially at risk from human activities. Ka Hōʻuluʻulu Ka Pōʻaiapili. ʻAʻole paha e kākoʻo nā keʻena kālā i ka noiʻina i nā lāhulu e ʻike kākaʻikahi ʻia a ʻaʻole hoʻi nui nā hola e lilo ana i ka launa ʻana me ia mau lāhulu inā hoʻi ʻaʻole nō lākou ke kia o ka noiʻina. No laila, ʻoi loa aku ke emi o ka ʻike i ia mau lāhulu ma mua o ka nui o ka launa pū ʻana aku. Nā Pahuhopu. No ka loaʻa ʻana o ka ʻikepili o nā koholā niho ma Hawaiʻi ma ka wā hoʻokahi o ke kālailai ʻia ʻana o nā mea laha. Nā Kiʻina Hana. Ma ka noiʻi hikiāloa ma kekahi waʻapā, hoʻomakakoho mākou i nā hola e launa ana me nā lāhulu e ʻike kākaʻikahi ʻia, i ka ʻohi ʻana mai i nā kiʻi me nā hāpana ʻokina, a i ka hoʻolēpili ukali ʻana. Hoʻololi ʻia ka nui o nā hāpana i nā kiʻi i ʻohi ʻia mai ke kaiāulu a me nā kānaka noiʻi ʻē aʻe, a pēlā pū i nā hāpana ōewe o nā holoholona ili me nā kānaka noiʻi ʻē aʻe. Kālailai ʻia ka hopena o nā hāpana ōewe me nā wehewehena ʻikepili lepili i loko ka pōʻaiapili o ka hoʻonoho launa a me nā moʻokūʻauhau ʻike hou ʻana. Nā hua nui. Mai loko mai o nā ʻikena i nā koholā niho, ʻike ʻia nā koholā luku ʻiʻi (Feresa attenuata) he ʻuʻuku iho o ka ʻelua pākēneka, a kū ka pinepine o ka ʻike ʻia ʻana i ka hohonu a puni nā mokupuni. Hōʻike ʻia nā kiʻi, pili he 318 mai loko mai o ka 443 i ka ʻūmaupaʻa nui o ka hoʻonoho launa. ʻAʻole i nui ka holo ʻana i waena o nā mokupuni, hōʻike ʻia naʻe ke kū loa o nā mea ma kai aku o Oʻahu me Hawaiʻi i ka leo, like naʻe kekahi ōewe hoʻoilina i waena o nā pūʻulu noho o kēlā me kēia mokupuni. ʻAʻohe pilina o ʻekolu pūʻulu i pili i nā nuʻa ili o ʻelua makahiki ʻokoʻa i ka ʻūmaupaʻa nui o ka hoʻonoho launa, a ʻaʻole hoʻi i kaʻana like ʻia kekahi mau ōewe hoʻoilina me nā pūʻulu noho ʻike mua ʻia. Nā hopena. He kiʻina hana kūpono ka hoʻomakakoho ʻana i nā lāhulu ʻike kākaʻikahi ʻia no ka hāpana hou ʻana i mea e mōakāka hou aku ai ka ʻike no nā lāhulu laha ʻole. Nā panina manaʻo. He mea koʻikoʻi nō pha kēia ʻano kiʻina hana no ka hoʻopihapiha ʻana aku i nā ʻikepili kōā no nā lāhulu pā paha i nā hana kānaka. -- Robin W. Baird, Ph.D. Hawai‘i Program Director Cascadia Research Collective<https://cascadiaresearch.org/> 218 ½ W. 4th Avenue Olympia, WA 98501 USA Cascadia on Facebook<https://www.facebook.com/CascadiaResearch/> Cascadia on Twitter<https://twitter.com/cascadiares> Updates from our Oct/Nov Kona effort<https://cascadiaresearch.org/hawaii-update/nov2023/> Recent publications from our group<https://cascadiaresearch.org/hawaii_publications/>: Baird, R.W., S.D. Mahaffy, B. Hancock-Hanser, T. Cullins, K.L. West, M.A. Kratofil, D.M. Barrios, A.E. Harnish, P.C. Johnson. 2024. Long-term strategies for studying rare species: results and lessons from a multi-species study of odontocetes around the main Hawaiian Islands. Pacific Conservation Biology 30, PC23027. https://doi.org/10.1071/PC23027 Mahaffy, S.D., R.W. Baird, A.E. Harnish, T. Cullins, S.H. Stack, J.J. Currie, A.L. Bradford, D.R. Salden, and K.K. Martien. 2023. Identifying social clusters of endangered main Hawaiian Islands false killer whales. Endangered Species Research 51:249-268. https://doi.org/10.3354/esr01258 Harnish, A.E., R.W. Baird, E. Corsi, A.M. Gorgone, D. Perrine, A. Franco, C. Hankins, and E. Sepeta. 2023. Long-term associations of common bottlenose dolphins with a fish farm in Hawai‘i and impacts on other protected species. Marine Mammal Science 39(3):794-810. https://doi.org/10.1111/mms.13010 Kratofil, M.A., A.E. Harnish, S.D. Mahaffy, E.E. Henderson, A.L. Bradford, S.W. Martin, B.A. Lagerquist, D.M. Palacios, E.M. Oleson, and R.W. Baird. 2023. Biologically important areas II for cetaceans within U.S. and adjacent waters — Hawai‘i region. Frontiers in Marine Sciences, 10:1053581. https://doi.org/10.3389/fmars.2023.1053581 Baird, R.W., S.D. Mahaffy, and J.K. Lerma. 2022. Site fidelity, spatial use, and behavior of dwarf sperm whales in Hawaiian waters: using small-boat surveys, photo-identification, and unmanned aerial surveys to study a difficult-to-study species. Marine Mammal Science 38(1):326-348. https://doi.org/10.111/mms.12861