scholarly journals Test of unmanned surface vehicles to conduct remote focal follow studies of a marine predator

2020 ◽  
Vol 635 ◽  
pp. 1-7
Author(s):  
CE Kuhn ◽  
A De Robertis ◽  
J Sterling ◽  
CW Mordy ◽  
C Meinig ◽  
...  
Keyword(s):  
Animal Behavior ◽  
Depth Distribution ◽  
Separation Distance ◽  
Callorhinus Ursinus ◽  
Unmanned Surface Vehicles ◽  
Marine Predator ◽  
Marine Predators ◽  
Fur Seals ◽  
Fur Seal ◽  
Solar Powered

We tested the feasibility of using Saildrone unmanned wind- and solar-powered surface vehicles to conduct remote focal follow studies of northern fur seals Callorhinus ursinus. Using Argos satellite and transmitted GPS locations, the Saildrones followed a fur seal while recording oceanographic conditions and mapping prey abundance and depth distribution using a scientific echosounder. The Saildrones successfully followed 6 fur seals over 2.4 ± 0.2 d (mean ± SE) and 149.7 ± 16.3 km of the foraging path. Median separation distance between the Saildrone and fur seal path was 0.65 ± 0.1 km and average time separation was 9.9 ± 1.4 h, with minimum time separations ranging from 1.9-4.9 h. Time and distance separation were a function of both animal behavior and study design. Our results show that Saildrones can approach satellite tracked marine predators from long distances and follow them over extended periods while collecting oceanographic and prey data. These successful focal follows demonstrate that unmanned surface vehicles are a valuable tool for collecting data on fine-scale relationships between marine predators, their prey, and the environment.

Separation of foraging habitat among breeding sites of a colonial marine predator, the northern fur seal (Callorhinus ursinus)

2004 ◽  
Vol 82 (1) ◽  
pp. 20-29 ◽  
Author(s):  
Bruce W Robson ◽  
Michael E Goebel ◽  
Jason D Baker ◽  
Rolf R Ream ◽  
Thomas R Loughlin ◽  
...  
Keyword(s):  
Breeding Site ◽  
Callorhinus Ursinus ◽  
Northern Fur Seal ◽  
Breeding Sites ◽  
Marine Predator ◽  
Fur Seals ◽  
Geographical Separation ◽  
Fur Seal ◽  
Satellite Transmitters ◽  
Breeding Seasons

This study examines whether lactating northern fur seals (Callorhinus ursinus) from different breeding sites on the Pribilof Islands in the eastern Bering Sea forage in separate areas. Satellite transmitters were attached to 97 northern fur seal females from nine breeding areas for 119 complete foraging trips during the 1995 and 1996 breeding seasons. Females from St. Paul and St. George islands tended to travel in different directions relative to their breeding site in both years of the study. St. Paul Island females dispersed in all directions except to the southeast, where St. George Island females foraged. Habitat separation was also observed among breeding areas on northeastern and southwestern St. Paul Island and to a lesser degree on northern and southern St. George Island. Although foraging direction led to geographical separation among sites, the maximum distance traveled and the duration of foraging trips did not differ significantly among islands in either year. The results of this study document that lactating fur seals from the same site share a common foraging area and that females from different breeding sites tend to forage in separate areas and hydrographic domains.

Spatial segregation and the influence of habitat on the foraging behavior of northern fur seals (Callorhinus ursinus)

2014 ◽  
Vol 92 (10) ◽  
pp. 861-873 ◽  
Author(s):  
C.E. Kuhn ◽  
R.R. Ream ◽  
J.T. Sterling ◽  
J.R. Thomason ◽  
R.G. Towell
Keyword(s):  
Conservation Strategy ◽  
Foraging Strategies ◽  
Habitat Segregation ◽  
Callorhinus Ursinus ◽  
Foraging Habitat ◽  
Northern Fur Seal ◽  
Dive Behavior ◽  
Fur Seals ◽  
Fur Seal ◽  
Northern Fur Seals

Central place foraging by colonial breeders can lead to depleted prey resources around breeding areas. Segregation of foraging areas both within and between large colonies may act as a mechanism to reduce competition for prey resulting in increased foraging success. We reassessed horizontal (spatial) foraging habitat segregation for northern fur seals (Callorhinus ursinus (L., 1758)) within and between colonies on the Pribilof Islands, Alaska (St. Paul and St. George islands), after the population declined by approximately 40%. Additionally, we examined vertical habitat segregation, where foraging ranges overlapped, and describe the influence of different foraging habitats on northern fur seal dive behavior. Spatial habitat segregation in northern fur seal foraging areas occurred between islands but was variable within islands, which is similar to the pattern previously described. There was no evidence for vertical habitat segregation when fur seals from different rookeries on St. George Island used the same foraging area. Additionally, fur seals from St. Paul Island rookeries that foraged in similar habitats showed fewer differences in dive behavior, indicating that foraging habitat plays a significant role in shaping dive behavior. The use of multiple foraging strategies within the Pribilof Island fur seal population could indicate that a complex management and conservation strategy may be necessary to stop the continuing decline of this population.

Pup Production Following Harvest of Female Northern Fur Seals

1981 ◽  
Vol 38 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Anne E. York ◽  
James R. Hartley
Keyword(s):  
Cohort Analysis ◽  
Survival Rates ◽  
Callorhinus Ursinus ◽  
Northern Fur Seal ◽  
Fur Seals ◽  
Fur Seal ◽  
Seal Population ◽  
Northern Fur Seals ◽  
Early Survival ◽  
The Difference

Female northern fur seals (Callorhinus ursinus) were harvested commercially from 1956 to 1968 and pelagic collections were taken for research purposes from 1958 to 1974. Early survival rates (birth to age 2) for males increased from an average of 0.32 before the harvest to 0.38 afterwards. Numbers of female pups whose births were precluded by the harvest are estimated for the years 1956–79; these account for about 70% of the difference between the numbers of pups actually born and the level of pup births before 1956. Estimates of the increased numbers of pups due to the increase in the early survival rates are presented for the years 1958–74.Key words: northern fur seal, population dynamics, female harvest, cohort analysis, St. Paul Island

scholarly journals Antarctophthirus nevelskoyi n.sp. (Anoplura: Echinophthiriidae) - a new species of parasite of the Northern fur seal (Callorhinus ursinus L., 1758) at Tyuleniy Island, Okhotsk Sea, Russia

2021 ◽  
Vol 16 (2) ◽  
pp. 17-25
Author(s):  
M. Yu. Shchelkanov ◽  
E. M. Shchelkanov ◽  
T. V. Moskvina
Keyword(s):  
New Species ◽  
Room Temperature ◽  
Scientific Literature ◽  
Far East ◽  
Callorhinus Ursinus ◽  
Okhotsk Sea ◽  
Northern Fur Seal ◽  
Fur Seals ◽  
Fur Seal ◽  
A New Species

Aim. To perform a morphological study of seal lice (Anoplura: Echinophthiriidae) of the genus Antarctophthirus Enderlein, 1906 taken from Northern fur seals (Callorhinus ursinus L., 1758) at Tyuleniy Island, Okhotsk Sea, Russia).Material and Methods. Seal lice were collected from the nasal passages of Northern fur seal C. ursinus pups during a scheduled ecological and virological expedition to Tyuleniy Island in August 2017. Fourteen samples of seal lice (11 imago males, 1 imago female, 1 nymph of the 2nd age, 1 nymph of the 3-rd age) were stored in 70% ethanol at room temperature from the time of collection until the start of the study. Morphological features of the insects were studied using light and scanning electron microscopy and compared with the available data in the scientific literature.Results. Unique patterns of the arrangement of spines were found in the examined samples that is a sufficient species feature for representatives of this family and allows the identification of a new species of seal lice.Conclusion. A new species of seal lice, Antarctophthirus nevelskoyi n.sp., was identified and described and named after the famous Russian explorer of the Far East, Admiral Gennady Ivanovich Nevelskoy (18131876).

scholarly journals Environmental influences on foraging effort, success and efficiency in female Australian fur seals

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cassie N. Speakman ◽  
Andrew J. Hoskins ◽  
Mark A. Hindell ◽  
Daniel P. Costa ◽  
Jason R. Hartog ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Large Scale ◽  
Population Level ◽  
Foraging Success ◽  
Foraging Effort ◽  
Climate Conditions ◽  
Marine Predators ◽  
Fur Seals ◽  
Fur Seal ◽  
Eastern Australia

Abstract Understanding the factors which influence foraging behaviour and success in marine mammals is crucial to predicting how their populations may respond to environmental change. The Australian fur seal (Arctocephalus pusillus doriferus, AUFS) is a predominantly benthic forager on the shallow continental shelf of Bass Strait, and represents the greatest biomass of marine predators in south-eastern Australia. The south-east Australian region is experiencing rapid oceanic warming, predicted to lead to substantial alterations in prey diversity, distribution and abundance. In the present study, foraging effort and indices of foraging success and efficiency were investigated in 138 adult female AUFS (970 foraging trips) during the winters of 1998–2019. Large scale climate conditions had a strong influence on foraging effort, foraging success and efficiency. Foraging effort and foraging success were also strongly influenced by winter chlorophyll-a concentrations and sea-surface height anomalies in Bass Strait. The results suggest increasing foraging effort and decreasing foraging success and efficiency under anticipated environmental conditions, which may have population-level impacts.

scholarly journals Swimming velocities in otariids

1990 ◽  
Vol 68 (10) ◽  
pp. 2105-2112 ◽  
Author(s):  
Paul J. Ponganis ◽  
Edward P. Ponganis ◽  
Katherine V. Ponganis ◽  
Gerald L. Kooyman ◽  
Roger L. Gentry ◽  
...  
Keyword(s):  
Metabolic Cost ◽  
Energy Costs ◽  
Callorhinus Ursinus ◽  
Northern Fur Seal ◽  
Cost Of Transport ◽  
Feeding Sites ◽  
Sea Lions ◽  
Fur Seals ◽  
Fur Seal ◽  
Time Partitioning

Velocities during surface swimming and diving were measured with microprocessor recorders in four otariid species: northern fur seals (Callorhinus ursinus), Galapagos sea lions (Zalophus californianus wollebaeki), Galapagos fur seals (Arctocephalus galapagoensis), and Hooker's sea lions (Phocarctos hookeri). Mean surface swimming velocities ranged from 0.6 to 1.9 m/s. Transit distances to feeding sites (1.2–90 km) were calculated using these velocities. Dive velocities, recorded every 15 s, ranged from 0.9 to 1.9 m/s. These velocities were consistent with calculated minimal cost of transport velocities in the smaller species. Using time partitioning, the metabolic cost of a northern fur seal foraging trip is estimated on the basis of recorded velocities and their calculated energy costs. This value is within 6% of that previously made with doubly labeled water techniques.

scholarly journals Analysis of commercial hunting on northern fur seal ( Callorhinus ursinus) at Tyuleny Island

2015 ◽  
Vol 183 (4) ◽  
pp. 71-80
Author(s):  
Alexey E. Kuzin
Keyword(s):  
Age Structure ◽  
Common Reason ◽  
Callorhinus Ursinus ◽  
Age Group ◽  
Commercial Fishery ◽  
Sex Composition ◽  
Northern Fur Seal ◽  
Fur Seals ◽  
Fur Seal ◽  
Commercial Hunting

Structure of commercial hunting on northern fur seal at Tyuleny Island is considered including effectiveness of podding, age-sex composition of the podded and captured animals, age structure of culled males, and reasons of culling. In total, the number from 2650 to 5099 of fur seals were podded during the harvest seasons of 1990-2008, 45.80 ± 2.17 % of them were killed and 54.20 ± 2.16 % were released. The bachelors prevailed among the podded animals, as well as in the bachelor rookeries (51.70 ± 2.56 %). The bulls were more numerous in the pod (35.80 ± 2.12 %) in compare with the half-bulls (10.20 ± 0.99 %) and the females (2.00 ± 0.85 %). Among the harvested animals, the bachelors prevailed, as well (93.50 ± 1.06 %), whereas the bulls, females, and half-bulls weren’t numerous (3.83 ± 0.87 %, 2.51 ± 0.67 %, 1.49 ± 0.29 %, respectively); frequency of the bulls and females captures changed from year to year. The most numerous age group of captured seals was the 3-year old animals (52.80 ± 1.60 %). All groups were presented among the culling animals, but the bachelors prevailed. The most common reason for culling was injuring of seals by commercial fishery wastes (scraps of fishing nets, ropes, packaging tapes, etc.): 64.20 ± 6.86 % of the culled animals were injured by the wastes.

Fetal growth of northern fur seals: life-history strategy and sources of variation

1991 ◽  
Vol 69 (10) ◽  
pp. 2608-2617 ◽  
Author(s):  
Andrew W. Trites
Keyword(s):  
Specific Growth ◽  
Research Effort ◽  
Life History Strategy ◽  
Growth Curves ◽  
Callorhinus Ursinus ◽  
Fur Seals ◽  
Fur Seal ◽  
History Of ◽  
Sources Of Variation ◽  
Fetal Size

Sex-specific growth curves are described for northern fur seal fetuses, Callorhinus ursinus. The relationships between body length, body mass, and gestational age are derived by regression analysis based on 7000 fetuses collected during 1958–1974 as part of a joint Canadian–American pelagic research effort. Male fetuses grow faster and larger than female fetuses. Length approaches an asymptote with time, but the increase in fetal mass appears exponential until parturition. The size of the fetus is influenced by the age, size, and reproductive history of the mother. Primiparous females produce smaller pups than multiparous females. This difference in fetal size is presumably due to physiological changes associated with having been previously pregnant and is not explained merely by differences in the size and age of the different parities. Older and larger females produce progressively larger fetuses until reaching their reproductive prime at about the age of 10–11 years. Adult females continue to grow beyond this age, but there is a senescent decline in the length and mass of the young they carry. There is no indication that the sex ratio differs from unity either between months, across years, or between mothers of different ages and parities.

Method of Determining Natural Mortality in the Northern Fur Seal (Callorhinus ursinus) from Known Pups and Kill by Age and Sex

1975 ◽  
Vol 32 (12) ◽  
pp. 2447-2452 ◽  
Author(s):  
Robert H. Lander
Keyword(s):  
Relative Error ◽  
Present Method ◽  
Callorhinus Ursinus ◽  
Natural Mortality ◽  
Northern Fur Seal ◽  
Fur Seals ◽  
Hypothetical Data ◽  
Fur Seal ◽  
Northern Fur Seals ◽  
Age And Sex

From known values of the number of northern fur seals, Callorhinus ursinus, born in a given year and the commercial kill of older animals of this species, by age and sex, a method is given for approximating natural mortality or survival 1) between times of birth and the first kill and 2) during the successive ages of kill. An example with hypothetical data indicates small relative error in these estimators, although bias may be considerable in certain of the associated age-specific estimators of abundance and exploitation rates. The problem of bias warrants further investigation. Estimates of natural survival from birth to the start of the kill at age 2 yr agree closely with independent tagging estimates for the 1964–66 year-classes of males from the Pnbilof Islands, Alaska. For this stock, further applications of the present method to the 1961–66 year-classes of males indicate natural survival of 31–42% during ages 0–2 yr and 84–89% annually during ages 2–5 yr.

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