Prevalence of interactions between Hawaiian monk seals (Nemonachus schauinslandi) and nearshore fisheries in the main Hawaiian Islands

We determine the prevalence and characteristics of interactions between the Hawaiian monk seal (Nemonachus schauinslandi) and nearshore fisheries in the main Hawaiian Islands and examine impacts to the subpopulation. We documented 139 monk seal–fisheries interactions between 1976 and 2014: 132 hookings typically involving large circle hooks accompanied by slide-bait rigging, and 7 gill-net entanglements. We individually identified 297 monk seals between 1988 and 2014 and recorded that 83 (28%) of these had at least one documented hooking or entanglement. Most individuals were aged two years or younger and a quarter of them were hooked or entangled multiple times. Documented fisheries interactions typically occurred at a monk seal’s natal island and most frequently on Kauai and Oahu. Fisheries interaction was directly implicated in 11 monk seal deaths and was slightly higher in frequency than other known mortality factors. The proportion of monk seals alive one year after a documented fisheries interaction varied by age class and ranged between 76% and 84%. Survival one year later for monk seals with a documented fisheries interaction versus matched controls (all age classes combined) was not significantly different. Nonetheless, fully understanding the scale and impacts of fisheries interactions, as well as mitigating these impacts, is important if the monk seal population of the main Hawaiian Islands is to maintain a positive growth trajectory.

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Geographic variation of persistent organic pollutants in Hawaiian monk seals Monachus schauinslandi in the main Hawaiian Islands

Endangered Species Research ◽

10.3354/esr00602 ◽

2014 ◽

Vol 24 (3) ◽

pp. 249-262 ◽

Cited By ~ 2

Author(s):

J Lopez ◽

KD Hyrenbach ◽

C Littnan ◽

GM Ylitalo

Keyword(s):

Geographic Variation ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Hawaiian Islands ◽

Monachus Schauinslandi ◽

Monk Seals

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The impact of power line-related mortality on the Cape Vulture Gyps coprotheres in a part of its range, with an emphasis on electrocution

Bird Conservation International ◽

10.1017/s095927091100013x ◽

2011 ◽

Vol 21 (3) ◽

pp. 311-327 ◽

Cited By ~ 35

Author(s):

ANDRÉ F. BOSHOFF ◽

JOHAN C. MINNIE ◽

CRAIG J. TAMBLING ◽

MICHAEL D. MICHAEL

Keyword(s):

Mortality Rate ◽

Power Line ◽

Power Lines ◽

National Database ◽

Annual Growth Rate ◽

Mortality Factors ◽

Positive Growth ◽

The Impact ◽

Annual Mortality ◽

Related Mortality

SummaryThe global population of the Cape Vulture Gyps coprotheres, a threatened southern African endemic, is known to be impacted by electrocutions and collisions on power line infrastructure, but to date this impact has not been estimated or quantified. Using data in a national database from the period prior to our study, conducted in the Eastern Cape Province of South Africa, we estimated a mean annual mortality rate from power line-related mortality of around 14 vultures per year. After applying an adjusted rate based on the results of a landowner survey, this estimate increased to around 80 vultures per year (i.e. a 5.7 fold increase). For a number of reasons, the estimated mean annual mortality rate is considered to under-represent the true situation, and must therefore be considered a minimum value. A simple model was constructed and run to investigate the potential impact of the mortality rate from electrocution on the study population. It distinguishes between vulture subpopulations in areas of high and low electrocution threat, and a migratory subpopulation that moves between these two areas. The model, simulated over 50 years and applying a constant theoretical maximum annual growth rate of 2%, indicates positive growth of the population in those areas where the electrocution threat from power lines is low, whereas the population in those areas where this threat is high is predicted to crash to extinction, from electrocution mortality alone, within a 20–35 year period. The regional population is predicted to show positive growth over the 50 year period. However, for a number of reasons that relate to the nature of certain parameters used in the model, the simulations must be considered to be conservative, at best. In addition, other unnatural mortality factors (notably inadvertent poisoning, drowning in high-walled farm reservoirs, harvesting for the traditional medicine trade, local food shortage), which are additive to power line-related mortality have not been taken into account. Management recommendations aimed at obtaining an improved estimate of the mean annual mortality rate from power lines, and at ameliorating the impact of electrocutions on the regional Cape Vulture population, are briefly mentioned. These address the former by documenting ways to improve the quantity and quality of the field data, and the latter by identifying areas where urgnt action needs to be taken to reduce or avoid the electrocution of vultures, by mitigating extant ‘unsafe’ power line infrastructure, and by ensuring that that only ‘safe’ infrastructure is used for new power lines.

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Foraging interaction between monk seals and large predatory fish in the Northwestern Hawaiian Islands

Endangered Species Research ◽

10.3354/esr00090 ◽

2008 ◽

Vol 4 ◽

pp. 299-308 ◽

Cited By ~ 23

Author(s):

FA Parrish ◽

GJ Marshall ◽

B Buhleier ◽

GA Antonelis

Keyword(s):

Hawaiian Islands ◽

Predatory Fish ◽

Northwestern Hawaiian Islands ◽

Monk Seals

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Population‐level impacts of natural and anthropogenic causes‐of‐death for Hawaiian monk seals in the main Hawaiian Islands

Marine Mammal Science ◽

10.1111/mms.12742 ◽

2020 ◽

Cited By ~ 1

Author(s):

Albert L. Harting ◽

Michelle M. Barbieri ◽

Jason D. Baker ◽

Tracy A. Mercer ◽

Thea C. Johanos ◽

...

Keyword(s):

Causes Of Death ◽

Hawaiian Islands ◽

Population Level ◽

Monk Seals

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Population status and seasonal haulout patterns of the southern elephant seal (Mirounga leonina) at Heard Island

Antarctic Science ◽

10.1017/s0954102099000061 ◽

1999 ◽

Vol 11 (1) ◽

pp. 38-47 ◽

Cited By ~ 14

Author(s):

David J. Slip ◽

Harry R. Burton

Keyword(s):

Total Population ◽

Elephant Seal ◽

Southern Elephant Seal ◽

Mirounga Leonina ◽

Population Status ◽

Elephant Seals ◽

Adult Females ◽

Seal Population ◽

Heard Island ◽

One Year

We surveyed the southern elephant seal population at Heard Island regularly from February 1992 to March 1993, and determined the haulout patterns of the major components of the population. While haulout patterns of moulting and immature seals may give broad indices of population trends, the breeding haulout of adult females was the only reliable haulout that could be used to determine annual pup production. During the breeding season 14 277 adult females were counted. Raw counts were corrected using two models, one purely mathematical and the other based on the haulout behaviour of adult female seals. The two models have slightly different assumptions, but both provided good fits to the observed haulout patterns and estimated total population with a coefficient of variation of less than 5%. Total pup production was estimated at between 17 000 and 18 000 for 1992. Previous counts of elephant seals from 1949–51, 1985 and 1987 were corrected using the same models. The two models gave estimates of the population that were within ± 2.5% for all but one year. The population declined by about 50% between 1949 and 1985 but there appears to have been little change from 1985–92. The previous decline may be related to changes in sea-ice.

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The Whales of Pender Harbour

Orca ◽

10.1093/oso/9780190673093.003.0013 ◽

2018 ◽

Author(s):

Jason M. Colby

Keyword(s):

Family Members ◽

San Juan ◽

The Sun ◽

Growing Up ◽

Killer Whales ◽

Late Afternoon ◽

Gill Net ◽

One Year ◽

First Time

By early 1968 , Cecil Reid Jr. had given some thought to orcas. A gill net fisherman based in Pender Harbour, the thirty-one-year-old Reid—“Sonny” to his friends—had seen many killer whales over the years. As a boy growing up in the 1940s, he heard locals grumble about blackfish, and he watched family members take shots at the animals as they passed by. “My grandfather lived out around the corner from Irvine’s Landing,” he recalled, “and when the whales showed up, they would get the guns out and start shooting them.” Yet Reid knew live killer whales had become lucrative commodities, and when his father suggested catching one, he decided to give it a try. It was winter, however, and there weren’t many orcas around. Then, to his surprise, they came to him. In the late afternoon of Wednesday, February 21, a pod wandered into Pender Harbour, passing Reid’s waterfront home on Garden Bay. Momentarily stunned, Reid raced down to his boat, Instigator One. “I just happened to have my San Juan net still on the drum—which is a lot deeper and touched bottom,” he later recounted. “So when they came into Garden Bay the first time, I just set my net across.” The whales eluded his first attempt, but they lingered in the harbor, and the following morning Reid convinced other fishermen to help him, including several of his brothers and members of the local Cameron and Gooldrup families. In all, nine fishermen worked to seal off Garden Bay, and as the sun set over Irvine’s Landing, Reid felt certain they had trapped at least three orcas. But that night, one of the nets tore loose, and in the morning only one whale remained. Disappointed, Reid and his partners secured the animal—a fifteen-footer they believed to be male. Like those caught previously, the trapped orca hesitated to challenge the frail net surrounding him, much to the fishermen’s relief. Within minutes, the animal was swimming placidly in its makeshift enclosure. “Maybe it likes it here,” mused Reid.

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Sighting patterns reveal unobserved pupping events to revise reproductive rate estimates for Hawaiian monk seals in the main Hawaiian Islands

Marine Mammal Science ◽

10.1111/mms.12761 ◽

2020 ◽

Author(s):

Stacie J. Robinson ◽

Albert L. Harting ◽

Tracy Mercer ◽

Thea C. Johanos ◽

Jason D. Baker ◽

...

Keyword(s):

Hawaiian Islands ◽

Reproductive Rate ◽

Monk Seals

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The response of ungulates to rainfall along the riverbeds of the Southern Kalahari

Koedoe ◽

10.4102/koedoe.v27i2.574 ◽

1984 ◽

Vol 27 (2) ◽

Cited By ~ 7

Author(s):

M. G. L Mills ◽

P. F Retief

Keyword(s):

Seasonal Pattern ◽

The Other ◽

Annual Rainfall ◽

Actual Number ◽

Mortality Factors ◽

Wet Season ◽

To Come ◽

One Year ◽

Connochaetes Taurinus ◽

Artificial Water

The responses of springbok Antidorcas marsupialis, gemsbok Oryx gazella, blue wildebeest Connochaetes taurinus and red hartebeest Alcelaphus buselaphus to rainfall along the riverbeds of the southern Kalahari are analysed. Springbok reacted most rapidly to rainfall along the riverbeds and, by browsing in dry times, maintained a fairly stable presence throughout the year, although the actual number present in any one year was dependent on annual rainfall. Gemsbok responded more slowly to rainfall and reached their highest numbers in years of high rainfall when the grasses were tall and mature, after which they rapidly departed from the riverbeds. Red hartebeest also reached their highest numbers during the rainy season, but departed slightly more slowly than gemsbok. In dry years, they too, failed to come into the riverbeds. Blue wildebeest in the vicinity of the riverbeds tended to be more sedentary than the other species. The presence of potable artificial water appeared to be more important for wildebeest than for the other species and, although rainfall was undoubtedly an important factor in regulating their numbers along the riverbeds, they depended to a greater extent on breeding success and mortality factors, than on emigration and immigration. The overall seasonal pattern of ungulate abundance along the riverbeds in the southern Kalahari was one of wet season concentrations and dry season dispersion.

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