Decline in sea otter (Enhydra lutris) populations along the Alaska Peninsula, 1986–2001

During the 1990s, sea otter (Enhydra lutris) counts in the Aleutian archipelago decreased by 70% throughout the archipelago between 1992 and 2000. Recent aerial surveys in the Aleutians did not identify the eastward extent of the decline; therefore we conducted an aerial survey along the Alaska Peninsula for comparison with baseline information. Since 1986, abundance estimates in offshore habitat have declined by 27– 49% and 93 –94% in northern and southern Alaska Peninsula study areas, respectively. During this same time period, sea otter density has declined by 63% along the island coastlines within the south Alaska Peninsula study area. Between 1989 and 2001, sea otter density along the southern coastline of the Alaska Peninsula declined by 35% to the west of Castle Cape but density increased by 4% to the east, which may indicate an eastward extent of the decline. In all study areas, sea otters were primarily concentrated in bays and lagoon, whereas historically, large rafts of otters had been distributed offshore. The population declines observed along the Alaska Peninsula occurred at roughly the same time as declines in the Aleutian islands to the east and the Kodiak archipelago to the west. Since the mid-1980s, the sea otter population throughout southwest Alaska has declined overall by an estimated 56–68%, and the decline may be one of the most significant sea otter conservation issues in our time

Effects of Active Sitting on Reading and Typing Task Productivity

International Journal of Exercise Science 12(5): 1216-1224, 2019. Increased sedentary behavior and reduced physical activity among children and adults has led to the advent of various active devices to combat these behaviors. Active sitting, consisting of modified chairs or stability balls, allows the body to stay dynamic while seated. While research has evaluated the health benefits of active sitting, minimal research has shown the effects of active sitting on productivity in adult populations. The purpose was to evaluate the effects of various chairs (active versus non-active) on typing and reading task productivity. Twenty adult participants performed typing and reading tasks for 10-minutes while sitting on each of the following: standard chair (SC), stability ball (SB), and active sitting chair (ST). Reading comprehension (RC), words per minute (WPM), accuracy, and errors were measured following each task. Additionally, perceived productivity was measured using a self-reported rating of difficulty scale (1-10). In terms of RC, there was no difference between the chairs (p = 0.16). However, perceived productivity was significantly greater on the SC as compared to SB (p \u3c 0.01) and ST (p \u3c 0.01). For the typing task, no differences were demonstrated for errors (p = 0.87) or accuracy (p = 0.91). However, WPM was significantly greater on SC (38.8 ± 10.5) compared to ST (35.9 ± 9.5) (p = 0.02). For perceived typing productivity, SC and SB demonstrated significantly greater values compared to ST (p \u3c 0.01). Results suggest that various types of active sitting may have a minimal negative effect on workplace performance and perceived productivity

Phocine Distemper Virus in Northern Sea Otters in the Pacific Ocean, Alaska, USA

Phocine distemper virus (PDV) has caused 2 epidemics in harbor seals in the Atlantic Ocean but had never been identified in any Pacific Ocean species. We found that northern sea otters in Alaska are infected with PDV, which has created a disease threat to several sympatric and decreasing Pacific marine mammals

A generalized method to determine detectability of rare and cryptic species using the ornate box turtle as a model

Estimates regarding population parameters are often based on data from surveys. To ensure that such estimates are as accurate as possible, it is important to know the detectability resulting from the particular survey method used. We used radiotelemetry to measure detectability of ornate box turtles (Terrapene ornata), using visual-encounter surveys in a sand prairie in northwestern Illinois, USA. We found that the overall detection probability of visual-encounter surveys was 0.03, and our high frequency of nondetection was due to a failure to detect visible turtles rather than turtles being underground or hidden in dense vegetation. Despite the substantial population density at our study site, visual-encounter surveys failed to detect box turtles on most visits, which resulted in a prohibitively high number of surveys that would be required to accurately estimate population size or to infer absence of the species from a site. Our method of using radiotelemetry to measure detection probability of a survey method could be easily applied to other small, cryptic, or rare species. However, our low detection probability and high frequency of nondetections recommend against use of visual-encounter surveys alone in estimating population parameters for ornate box turtles. © 2011 The Wildlife Society

Habitat alteration and survival rates of the ornate box turtle

Habitat destruction and modification may be the most prominent anthropogenic forces affecting extant biological systems. Growing evidence suggests that turtles are especially vulnerable to many anthropogenic stressors. We evaluated the effects of habitat modification on survival rates of the threatened ornate box turtle (Terrapene ornata) in northwest Illinois, USA, using a 20‐year mark‐recapture dataset. Longstanding development (i.e., cottages, outbuildings, landscape management) reduced the apparent survival of the ornate box turtle, especially among females. In contrast, smaller, more recent development (i.e., construction and paving of a bike path) did not have demonstrable negative effects on apparent survival. Our results indicate that the scale of development is important to consider in management and that adverse effects of anthropogenic development may require a considerable time frame to manifest in long‐lived organisms

High Natality Rates of Endangered Steller Sea Lions in Kenai Fjords, Alaska and Perceptions of Population Status in the Gulf of Alaska

Steller sea lions experienced a dramatic population collapse of more than 80% in the late 1970s through the 1990s across their western range in Alaska. One of several competing hypotheses about the cause holds that reduced female reproductive rates (natality) substantively contributed to the decline and continue to limit recovery in the Gulf of Alaska despite the fact that there have been very few attempts to directly measure natality in this species. We conducted a longitudinal study of natality among individual Steller sea lions (n = 151) at a rookery and nearby haulouts in Kenai Fjords, Gulf of Alaska during 2003–2009. Multi-state models were built and tested in Program MARK to estimate survival, resighting, and state transition probabilities dependent on whether or not a female gave birth in the previous year. The models that most closely fit the data suggested that females which gave birth had a higher probability of surviving and giving birth in the following year compared to females that did not give birth, indicating some females are more fit than others. Natality, estimated at 69%, was similar to natality for Steller sea lions in the Gulf of Alaska prior to their decline (67%) and much greater than the published estimate for the 2000s (43%) which was hypothesized from an inferential population dynamic model. Reasons for the disparity are discussed, and could be resolved by additional longitudinal estimates of natality at this and other rookeries over changing ocean climate regimes. Such estimates would provide an appropriate assessment of a key parameter of population dynamics in this endangered species which has heretofore been lacking. Without support for depressed natality as the explanation for a lack of recovery of Steller sea lions in the Gulf of Alaska, alternative hypotheses must be more seriously considered

Predation on an Upper Trophic Marine Predator, the Steller Sea Lion: Evaluating High Juvenile Mortality in a Density Dependent Conceptual Framework

The endangered western stock of the Steller sea lion (Eumetopias jubatus) – the largest of the eared seals – has declined by 80% from population levels encountered four decades ago. Current overall trends from the Gulf of Alaska to the Aleutian Islands appear neutral with strong regional heterogeneities. A published inferential model has been used to hypothesize a continuous decline in natality and depressed juvenile survival during the height of the decline in the mid-late 1980's, followed by the recent recovery of juvenile survival to pre-decline rates. However, these hypotheses have not been tested by direct means, and causes underlying past and present population trajectories remain unresolved and controversial. We determined post-weaning juvenile survival and causes of mortality using data received post-mortem via satellite from telemetry transmitters implanted into 36 juvenile Steller sea lions from 2005 through 2011. Data show high post-weaning mortality by predation in the eastern Gulf of Alaska region. To evaluate the impact of such high levels of predation, we developed a conceptual framework to integrate density dependent with density independent effects on vital rates and population trajectories. Our data and model do not support the hypothesized recent recovery of juvenile survival rates and reduced natality. Instead, our data demonstrate continued low juvenile survival in the Prince William Sound and Kenai Fjords region of the Gulf of Alaska. Our results on contemporary predation rates combined with the density dependent conceptual framework suggest predation on juvenile sea lions as the largest impediment to recovery of the species in the eastern Gulf of Alaska region. The framework also highlights the necessity for demographic models based on age-structured census data to incorporate the differential impact of predation on multiple vital rates

Effects of Active Sitting on Typing and Reading Task Productivity

Increased sedentary behavior and reduced physical activity among children and adults has led to the advent of various active devices to combat these behaviors. Active sitting, consisting of modified chairs or stability balls, allows the body to stay dynamic while seated. While research has evaluated the health benefits of active sitting, minimal research has shown the effects of active sitting on productivity in adult populations. PURPOSE: The purpose was to evaluate the effects of various chairs (active versus non-active) on typing and reading task productivity. METHODS: Twenty adult participants performed typing and reading tasks for 10-minutes while sitting on each of the following: standard chair (SC), stability ball (SB), and active sitting chair (ST). Reading comprehension (RC), words per minute (WPM), accuracy, and errors were measured following each task. Additionally, perceived productivity was measured using a self-reported rating of difficulty scale (1-10). RESULTS: In terms of RC, there was no difference between the chairs (p=0.16). However, perceived productivity was significantly greater on the SC as compared to SB (ppp=0.87) or accuracy (p=0.91). However, WPM was significantly greater on SC (38.8 ± 10.5) compared to ST (35.9 ± 9.5) (p=0.02). For perceived typing productivity, SC and SB demonstrated significantly greater values compared to ST (pCONCLUSIONS: Results suggest that various types of active sitting may have a minimal negative effect on workplace performance and perceived productivity