{"id":749395,"date":"2026-07-07T23:21:15","date_gmt":"2026-07-07T23:21:15","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/749395\/"},"modified":"2026-07-07T23:21:15","modified_gmt":"2026-07-07T23:21:15","slug":"hawai%ca%bbi-island-spinner-dolphins-are-producing-fewer-calves-new-study-reveals-big-island-now","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/749395\/","title":{"rendered":"Hawai\u02bbi Island spinner dolphins are producing fewer calves, new study reveals : Big Island Now"},"content":{"rendered":"\n

Surveys of spinner dolphin populations off Hawai\u2018i Island conducted in 2021-2022 show unexpectedly low calf numbers, according to a recent study published by the University of Hawai\u2018i at M\u0101noa.<\/p>\n

Led by scientists with the university\u2019s Marine Mammal Research Program along with national and international collaborators, the research, published in Endangered Species Research<\/a>, determined that calves made up only about 9% of the population, a stark contrast to the 17% expected in a healthy, stable population, raising urgent concerns about the long-term survival of this isolated population.<\/p>\n

\"\"<\/a>Mother and calf spinner dolphins. (Photo courtesy: Fabien Vivier)<\/p>\n

\u201cThe evidence suggests chronic human disturbance \u2014 especially tourism and recreational-related interactions during critical dolphin resting periods \u2014 as a likely contributing factor affecting reproductive success and calf survival,\u201d said lead author Fabien Vivier, who was a doctoral student at the Hawai\u2018i Institute of Marine Biology in the UH M\u0101noa School of Ocean and Earth Science and Technology at the time of this work. \u201cThe findings support stronger conservation actions, such as time-area closures for human activities, alongside continued long-term monitoring\u2014actions that have long been called for.\u201d<\/p>\n

In the study published this year, scientists used drone photography to measure the body length of free-swimming dolphins, which revealed a decline in the number of calves. <\/p>\n

By combining these aerial measurements with age-length data from stranded spinner dolphins collected by Kristi West, study co-author and researcher with the UH Health and Stranding Lab at the UH M\u0101noa College of Tropical Agriculture and Human Resilience, the team created the first age-length growth curve for this specific population. This allowed them to accurately categorize individuals into calves (under 2 years), juveniles (2\u20139 years), and adults (over 9 years).<\/p>\n

Age structure is an early indicator of population health and long-term viability. The documented low proportion of calves suggests the spinner dolphin population off Hawai\u02bbi Island may not be replacing itself fast enough, which could lead to future population decline.<\/p>\n

\u201cThis study provides one of the first population-level demographic signals suggesting those long-term disturbances may now be affecting reproduction and calf survival,\u201d said Professor Lars Bejder, co-author on the study and MMRP director.<\/p>\n

With spinner dolphins following a predictable daily cycle \u2014 foraging offshore at night and returning to shallow coastal bays during the day to rest and socialize \u2014 they are especially vulnerable to tourism activities in these nearshore habitats.<\/p>\n

Snorkeling tours advertise whale and dolphin watching and in the past, companies have also marketed swimming with dolphins. As a result, previous research has shown that this population of dolphins off of Hawai\u2018i Island experiences the highest levels of disturbance exposure recorded for dolphins worldwide. <\/p>\n

According to the University of Hawai\u2018i press release, research from 2013 estimated that each individual dolphin is valued at more than $3.3 million over its lifetime and collectively, dolphin tourism generates more than $100 million annually for the state\u2019s economy.<\/p>\n

In an effort to curb harassment of the marine animals, the National Oceanic Atmospheric Administration\u2019s Marine Fishery Service implemented a law in September 2021 requiring people and vessels to stay 50 yards away from the dolphins.<\/p>\n

\"\"<\/a>A group of 33 swimmers were caught illegally chasing a pod of dolphins in H\u014dnaunau Bay on the Big Island. (Department of Land and Natural Resources)<\/p>\n

From January to November of 2024, 47 citations were issued, with 41 fines totaling $10,900. Violations occurred in H\u014dnaunau Bay, Honok\u014dhau Harbor, Ho\u2018okena Beach Park, Kailua Bay and Noio Point.<\/p>\n

In 2023, the agency issued 34 citations, resulting in $6,500 in fines. Violations occurred in Kealakekua Bay, Ho\u2018okena Beach Park, Kailua Bay, Keauhou Bay and Magic Sands Beach Park, with the most blatant occurring in March when 33 swimmers were caught aggressively pursuing a pod of dolphins in H\u014dnaunau Bay. All of them were cited and fined.<\/p>\n

According to the news release from the university, experts from the U.S. Marine Mammal Commission and the Pacific Scientific Review Group have argued that this measure is insufficient. The study authors are calling for stronger conservation actions, specifically time-area closures that would restrict human access to critical resting bays during the day.<\/p>\n

\u201cUnderstanding these impacts is critical for protecting an isolated local population before declines become irreversible,\u201d said Randall Wells, study co-author and director of Brookfield Zoo Chicago\u2019s Sarasota Dolphin Research Program. \u201cWe hope this work provides the science-based evidence needed to develop effective protections for spinner dolphins while helping balance marine tourism, cultural stewardship, and long-term ecosystem health in Hawai\u02bbi.\u201d<\/p>\n

Future research and monitoring will depend on available funding, with scientists aiming to track long-term changes in age structure, reproduction, and population and further refine non-invasive drone-based methods.<\/p>\n","protected":false},"excerpt":{"rendered":"Surveys of spinner dolphin populations off Hawai\u2018i Island conducted in 2021-2022 show unexpectedly low calf numbers, according to…\n","protected":false},"author":2,"featured_media":749396,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[305324,321421,19232,192,33142,321422,79,321423,22405,64764],"class_list":["post-749395","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-as-seen-on-instagram","tag-calf-survival","tag-conservation","tag-environment","tag-hawaii-island","tag-marine-mammal-research-program","tag-science","tag-spinner-dolphins","tag-tourism-impact","tag-university-of-hawaii"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/749395","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=749395"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/749395\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/749396"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=749395"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=749395"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=749395"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}