Dive Characteristics Research Articles

Movement and diving behavior of satellite-tagged male sperm whales in the Gulf of Alaska

Male sperm whales (Physeter macrocephalus) are known to interact with and depredate from commercial longline fishing vessels targeting sablefish (Anoplopoma fimbria) in the Gulf of Alaska (GOA). This study aims to better understand their movement patterns and diving behavior in this region, and in relation to depredation behavior. Between 2007 and 2016 a total of 33 satellite tags were deployed on sperm whales interacting with fishing vessels in the eastern GOA. A subset of these tags also collected dive characteristics. We used state space models to interpolate hourly positions from tags and estimate behavioral state from 29 usable tag records, 14 of which had associated dive information. Whales exhibited slower horizontal movement (1.4 km/hr) within GOA waters compared to south of the GOA (5.5 km/hr), indicating tagged whales sped up when they left the region. Behavioral states indicated primarily foraging behavior (82% of locations) in the GOA and primarily transiting behavior (74% of locations) when whales left the GOA. Dive data showed average ( ± Standard Deviation) maximum dive depths of 396 m ( ± 166), and dive durations of 32 min (± 9). Generalized additive models indicated that dives were significantly deeper and longer during the daytime than dawn, dusk, or nighttime, and dives were significantly deeper and shorter during quarter moons, when tidal currents are weakest. Maximum dive depth decreased in areas of higher sablefish CPUE, suggesting a potential link between the sablefish fishery and depredation behavior. As seafloor depth increased, up to 800 m, dives became deeper, indicating that whales were likely targeting both bathypelagic and mesopelagic prey. This highlights the importance of the GOA continental slope as a foraging ground for male sperm whales. This enhanced understanding of sperm whale foraging ecology informs management and conservation efforts in high latitude foraging grounds.

Pediatric Diving-Related Injuries in Swimming Pools Presenting to US Emergency Departments: 2008-2020.

Recreational swimming/diving is among the most common physical activities in US children and a significant cause of morbidity across the United States. This study updates the national epidemiology of diving-related injuries. The Consumer Product Safety Commission's National Electronic Injury Surveillance System database was queried for patients aged 0 to 19 from 2008 to 2020 who presented to any of the 100 National Electronic Injury Surveillance System-participating emergency departments for a diving-related injury. Dive characteristics such as dive height, dive skill, dive direction, and dive sequence were determined from case narratives. A total of 1202 cases were identified for analysis corresponding to a total national estimate of 37,387 diving related injuries during the period from 2008 to 2020 and a national incidence of 3.6 injuries per 100,000 population. Males accounted for 64% of injuries. The average yearly incidences of injury in the 10 to 14 and 15 to 19 age groups were identical at 5.8 per 100,000. Contact with the diving board or platform was the most common cause of injury (34%). Diving backwards or attempting a flip or handstand dive were associated with increased odds of sustaining an injury resulting from contact with the diving board or platform (odds ratio, 16.0 and 6.9, respectively). In 2020, the incidence of diving-related injury fell to 1.6 per 100,000 population. Diving injuries are common in children and adolescents, especially in boys aged 10 to 19. There was a significant reduction in diving-related injury corresponding with the COVID-19 pandemic.

Dive characteristics of Common Loons wintering in the Gulf of Mexico and off the southern U.S. Atlantic coast

Common Loons (<em>Gavia immer</em>) winter primarily in marine coastal areas and utilize a forage base that is poorly defined, especially for offshore areas. Information on dive activity is needed for describing foraging strategies and for inferring prey distribution. Archival geolocator tags were used to determine the wintering locations and dive characteristics of adult Common Loons captured and marked on breeding lakes in Minnesota, Wisconsin, and the Upper Peninsula of Michigan. Among loons that completed fall migration, most wintered in the Gulf of Mexico, with smaller proportions wintering off the southern Atlantic Coast or impoundments in the southeastern United States. Adult Common Loons tended to occupy offshore areas of the Gulf of Mexico and the Atlantic Ocean and, on average, spent about 60% of daylight hours foraging. Dive depths were as deep as 50 m (Gulf of Mexico) and dive characteristics indicated that loons were primarily foraging on benthic prey. Total dive duration, time at maximum depth, and post-dive surface intervals increased with dive depths among wintering Common Loons. Our results are expected to contribute to the understanding of the wintering ecology of Common Loons and be useful in informing regional and national conservation planning efforts.

On-Field Biomechanical Assessment of High and Low Dive in Competitive 16-Year-Old Goalkeepers through Wearable Sensors and Principal Component Analysis.

Diving saves are the main duty of football goalkeepers. Few biomechanical investigations of dive techniques have been conducted, none in a sport-specific environment. The present study investigated the characteristics of goalkeepers’ dive in preferred (PS) and non-preferred (nPS) side through an innovative wearables-plus-principal-component analysis (PCA) approach. Nineteen competitive academy goalkeepers (16.5 ± 3.0 years) performed a series of high and low dives on their PS and nPS. Dives were performed in a regular football goal on the pitch. Full-body kinematics were collected through 17 wearable inertial sensors (MTw Awinda, Xsens). PCA was conducted to reduce data dimensionality (input matrix 310,878 datapoints). PCA scores were extracted for each kinematic variable and compared between PS and nPS if their explained variability was >5%. In high dive, participants exhibited greater hip internal rotation and less trunk lateral tilt (p < 0.047, ES > 0.39) in PS than nPS. In low dives, players exhibited greater ipsilateral hip abduction dominance and lower trunk rotation (p < 0.037, ES > 0.40) in PS than nPS. When diving on their nPS, goalkeepers adopted sub-optimal patterns with less trunk coordination and limited explosiveness. An ecological testing through wearables and PCA might help coaches to inspect relevant diving characteristics and improve training effectiveness.

Dive characteristics of Cross Seamount beaked whales from long‐term passive acoustic monitoring at the Pacific Missile Range Facility, Kauaʻi

AbstractBeaked whale foraging pulses were detected on the Pacific Missile Range Facility (PMRF) off Kauaʻi, Hawaiʻi, via long term passive acoustic monitoring. The unidentified pulses do not match foraging pulses of known species on the range but are similar to the unidentified beaked whale first detected at Cross Seamount, Hawaiʻi. Although there has not been a visual confirmation of the unidentified beaked whale species, analysis of data collected from 2007 to 2019 has identified beaked whale foraging dive characteristics from echolocation pulses. From the 13 years of data, the most distinct patterns were that all foraging dives occurred at night and the nighttime foraging dive rate was 0.11 group vocal periods (GVP) per hour, with most detections on shallow hydrophones (625–1,000 m deep) over steep bathymetric slopes. Data collected during U.S. Navy training events were used to compare dive behavior during mid‐frequency active sonar (MFAS) activity against baseline periods; it was determined that the whales reduced GVPs during sonar and these remained low for at least 3 days after the training events. These results are the first long‐term record of acoustic signals from the Cross Seamount beaked whale and provide important insights into their habitat use and occurrence patterns.

Year-Round Dive Characteristics of Male Beluga Whales From the Eastern Beaufort Sea Population Indicate Seasonal Shifts in Foraging Strategies

Dive behavior represents multiple ecological functions for marine mammals, but our understanding of dive characteristics is typically limited by the resolution or longevity of tagging studies. Knowledge on the time-depth structures of dives can provide insight into the behaviors represented by vertical movements; furthering our understanding of the ecological importance of habitats occupied, seasonal shifts in activity, and the energetic consequences of targeting prey at a given depth. Given our incomplete understanding of Eastern Beaufort Sea (EBS) beluga whale behavior over an annual cycle, we aimed to characterize dives made by belugas, with a focus on analyzing shifts in foraging strategies. Objectives were to (i) characterize and classify the range of beluga-specific dive types over an annual cycle, (ii) propose dive functions based on optimal foraging theory, physiology, and association with environmental variables, and (iii) identify whether belugas undergo seasonal shifts in the frequency of dives associated with variable foraging strategies. Satellite-linked time-depth-recorders (TDRs) were attached to 13 male belugas from the EBS population in 2018 and 2019, and depth data were collected in time series at a 75 s sampling interval. Tags collected data for between 13 and 357 days, including three tags which collected data across all months. A total of 90,211 dives were identified and characterized by twelve time and depth metrics and classified into eight dive types using a Gaussian mixed modeling and hierarchical clustering analysis approach. Dive structures identify various seasonal behaviors and indicate year-round foraging. Shallower and more frequent diving during winter in the Bering Sea indicate foraging may be energetically cheaper, but less rewarding than deeper diving during summer in the Beaufort Sea and Arctic Archipelago, which frequently exceeded the aerobic dive limit previously calculated for this population. Structure, frequency and association with environmental variables supports the use of other dives in recovery, transiting, and navigating through sea ice. The current study provides the first comprehensive description of the year-round dive structures of any beluga population, providing baseline information to allow improved characterization and to monitor how this population may respond to environmental change and increasing anthropogenic stressors.

Water temperature is a key driver of horizontal and vertical movements of an ocean giant, the whale shark Rhincodon typus

Integrated analysis of the vertical and horizontal movements of epipelagic fishes requires high-resolution data from tags that have been attached to animals for long periods. The recovery of a SPLASH tag deployed on a whale sharkRhincodon typusfor 3 mo enabled access to archival data of horizontal and vertical movements of the shark that travelled 5380 km from Christmas Island to the Banda Sea. We examined water temperature and bathymetry to compare movements of the shark with key oceanographic features. Over 89 d, we identified 1931 dives and grouped these into 5 broad categories depending on dive shape. To investigate the potential for these dives to reflect behavioural thermoregulation, we used boosted regression trees to model the relationship between pre- and post-dive surface durations and dive characteristics. The movements of the shark were correlated with water temperatures, with the animal following frontal systems while remaining in a sea surface temperature (SST) range of 24-29°C. Across the continental shelf off north-western Australia, the shark mostly remained near the seafloor, likely avoiding very warm SSTs and strong currents at the surface. U- (foraging) and V- (searching) shaped dives accounted for ~78% of dives. Foraging dives during the day descended to 200-500 m and were preceded and followed by extended periods at the surface, whereas at night, the shark rarely dived below 200 m, likely foraging near the thermocline. Our results show how water temperatures influence the movement of this whale shark, with ‘basking’ at the surface during the day likely to gather environmental heat for thermoregulation, aiding to maintain body temperatures.

Long-term foraging dive characteristics of Cross Seamount beaked whales at the Pacific Missile Range Facility

Beaked whale foraging dive clicks similar to those detected at Cross Seamount were detected during passive acoustic monitoring of marine mammals at the Pacific Missile Range Facility (PMRF) off Kauai, Hawaii using bottom-mounted hydrophones from January 2007 through August 2018. The Cross Seamount beaked whale (BWC) foraging dive click frequency sweeps from approximately 18 kHz to above the recording bandwidth of the PMRF sensors of 48 kHz at inter-click-intervals of 0.14 s (std 0.06 s). These unique clicks have only been detected at Cross Seamount and around the Hawaiian Islands, and because they have only been detected at night there has been no visual detections or species confirmation. However, they are distinctive enough to automatically detect, and can be used to describe basic presence at PMRF. Detections averaged 0.047 dives/h (in a 24-h cycle), and occurred almost entirely on the southern part of the range (water depth <1000 m). 702 BWC foraging dives were used to determine a foraging dive baseline over a 12-year period, to compare foraging dive rates during US Naval exercise events and baseline periods, and to contrast BWC foraging dive behavior from Blainville’s beaked whale foraging dive behavior at PMRF.Beaked whale foraging dive clicks similar to those detected at Cross Seamount were detected during passive acoustic monitoring of marine mammals at the Pacific Missile Range Facility (PMRF) off Kauai, Hawaii using bottom-mounted hydrophones from January 2007 through August 2018. The Cross Seamount beaked whale (BWC) foraging dive click frequency sweeps from approximately 18 kHz to above the recording bandwidth of the PMRF sensors of 48 kHz at inter-click-intervals of 0.14 s (std 0.06 s). These unique clicks have only been detected at Cross Seamount and around the Hawaiian Islands, and because they have only been detected at night there has been no visual detections or species confirmation. However, they are distinctive enough to automatically detect, and can be used to describe basic presence at PMRF. Detections averaged 0.047 dives/h (in a 24-h cycle), and occurred almost entirely on the southern part of the range (water depth <1000 m). 702 BWC foraging dives were used to determine a foraging dive baseli...

Country borders and the value of scuba diving in an estuary

In the face of restricted budgets, it is worthwhile to explore whether domestic and non-domestic users would be willing to contribute to the cost of managing natural areas. Specifically, we investigate preferences of Dutch and Belgian divers for a trip to the Oosterschelde, an estuary in the Netherlands close to Belgium. The travel cost estimates based on day trips reveal a consumer surplus of 108 and 197 euro per diving trip for Dutch and Belgian divers respectively. This leads to an estimated total access value of 21.7 million euro per year for recreational diving in the Oosterschelde. The choice experiment reveals little difference between preferences for dive characteristics of Dutch and Belgian respondents, with the exception of the presence of having a pub nearby and the difficulty of the dive. Yet, overall Belgian respondents have a higher willingness for diving in the Oosterschelde than Dutch respondents. While payment schemes, such as diving tags, can be interesting options for the agency to finance management of natural areas, limited public support and high administrative costs may be important obstacles.

Spatial segregation contrasting dietary overlap: niche partitioning of two sympatric alcids during shifting resource availability

Interspecific interactions help to shape individual- and population-level dynamics. As such, similar species breeding sympatrically are expected to have a high potential for competition and, thus, may have developed strategies to reduce niche overlap to allow coexistence. We combined GPS tracking and stable isotope analysis (δ15N, δ13C) to simultaneously compare multiple behavioral and dietary niche dimensions of common murres (Uria aalge) and razorbills (Alca torda) breeding at nearby colonies (55 km apart) on the northeastern Newfoundland coast under varying prey availability in 2017. Though foraging ranges of species had high potential overlap (5000 km2), foraging areas of the two species were spatially segregated. Dive characteristics also differed, as predicted based on body size and dive capacity. These differences contrasted a high degree of overlap in diet, habitat characteristics, and diurnal foraging patterns, suggesting that spatial segregation may be the most important factor to allow coexistence of these similar species for the same limited resources. As prey availability increased later in the breeding season, individual murres and razorbills foraged closer to their respective colonies and population-level diet composition changed, indicative of reduced energy costs and dietary plasticity to take advantage of highly available prey, capelin (Mallotus villosus). Foraging areas, however, remained segregated. Seabirds and marine systems face many potential threats, the greatest of which may be climate change. Thus, understanding variation in space, time, and habitat selection among similar species allowed for a more comprehensive view of the possible ways these species may partition their niche and how future changes to resource availability could impact interspecific relationships.

High individual flexibility in the foraging behavior of a marine predator, the common murre

The foraging ecology of breeding seabirds is largely influenced by prey availability and energy demands related to reproduction which, in combination with other factors, can affect resource specialization in space and time. In this study, we combined GPS tracking, dive behavior, and stable isotope ratios of carbon and nitrogen to examine behavioral and dietary flexibility within individuals in a breeding pursuit-diving seabird, the common murre (Uria aalge), on the northeast Newfoundland coast. We examined individual flexibility over 2 years (2016, 2017) during which the timing of arrival and availability of their primary prey, capelin (Mallotus villosus), varied. In both years, we found high within-individual variation in foraging trip and dive characteristics, coupled with low spatial overlap of foraging trips both within and among individuals, indicative of flexible behavior. Concurrently, the isotopic niche of breeding common murres showed a higher degree of dietary consistency, evidenced by similar amounts of variation within and among individuals in stable isotope ratios (δ13C, δ15N). Dietary reconstruction revealed that the proportion of different prey types in the diet varied across individuals, suggesting a degree of dietary flexibility. When capelin (prey) availability was low (in 2017), foraging trips were longer and farther from the colony, maximum dive duration decreased, and the proportion of capelin in the diet decreased. Behavioral flexibility, however, remained similar across both years, regardless of prey availability. Our results suggest that common murres can tolerate and respond to fluctuations in prey availability through flexible foraging strategies. Increased foraging distances during low capelin availability suggest increased energetic costs, and thus, an energetic threshold may be reached above which lower prey availability cannot be tolerated.

Constrained by consistency? Repeatability of foraging behavior at multiple timescales for a generalist marine predator

Marine predators frequently exhibit consistency in foraging behaviors despite the dynamic nature of marine ecosystems, which has the potential for ecological and evolutionary implications depending on the timescale at which it persists. We examined behavioral consistency in movements and diving behavior of adult female California sea lions (Zalophus californianus), which are abundant, generalist central-place foragers inhabiting an ecosystem characterized by small- and broad-scale oceanographic variability. We used biologging devices to measure repeatability of behavior within a season and stable isotope analysis of whiskers to quantify behavior across a 2-year period associated with anomalous environmental conditions that affected prey availability. Sea lions were significantly repeatable in all variables across multiple timescales (Radj = 0.26–0.82), although repeatability estimates were generally higher for variables related to characteristics of individual dives (e.g., dive depth) than those that described dive bouts (e.g., bout duration) or spatial use (e.g., volume of 3D utilization distribution). These differences may result from the fact that diving behaviors vary with prey type, whereas spatial use and bout variables may reflect the foraging success within prey patches or movement among patches. There was variation in how predictable individual sea lions were in their diving behaviors, which was largely unrelated or negatively related to foraging site fidelity. The strength of behavioral consistency decreased with time yet persisted across the 2-year period, suggesting that while sea lions alter their behavior in response to environmental change, the behavioral flexibility of individuals may ultimately be constrained by consistency.

Distribution and foraging patterns of common loons on Lake Michigan with implications for exposure to type E avian botulism

Abstract Common loons (Gavia immer) staging on the Great Lakes during fall migration are at risk to episodic outbreaks of type E botulism. Information on distribution, foraging patterns, and exposure routes of loons are needed for understanding the physical and ecological factors that contribute to avian botulism outbreaks. Aerial surveys were conducted to document the spatiotemporal distribution of common loons on Lake Michigan during falls 2011–2013. In addition, satellite telemetry and archival geolocator tags were used to determine the distribution and foraging patterns of individual common loons while using Lake Michigan during fall migration. Common loon distribution observed during aerial surveys and movements of individual radiomarked and/or geotagged loons suggest a seasonal pattern of use, with early fall use of Green Bay and northern Lake Michigan followed by a shift in distribution to southern Lake Michigan before moving on to wintering areas. Common loons tended to occupy offshore areas of Lake Michigan and, on average, spent the majority of daylight hours foraging. Dive depths were as deep as 60 m and dive characteristics suggested that loons were primarily foraging on benthic prey. A recent study concluded that round gobies (Neogobius melanostomus) are an important prey item of common loons and may be involved in transmission of botulinum neurotoxin type E. Loon distribution coincides with the distribution of dreissenid mussel biomass, an important food resource for round gobies. Our observations support speculation that energy transfer to higher trophic levels via gobies may occur in deep-water habitats, along with transfer of botulinum neurotoxin.

Swimming and diving energetics in dolphins: a stroke-by-stroke analysis for predicting the cost of flight responses in wild odontocetes

Exponential increases in hydrodynamic drag and physical exertion occur when swimmers move quickly through water, and underlie the preference for relatively slow routine speeds by marine mammals regardless of body size. Because of this and the need to balance limited oxygen stores when submerged, flight (escape) responses may be especially challenging for this group. To examine this, we used open-flow respirometry to measure the energetic cost of producing a swimming stroke during different levels of exercise in bottlenose dolphins (Tursiops truncatus). These data were then used to model the energetic cost of high-speed escape responses by other odontocetes ranging in mass from 42 to 2738 kg. The total cost per stroke during routine swimming by dolphins, 3.31±0.20 J kg-1stroke-1, was doubled during maximal aerobic performance. A comparative analysis of locomotor costs (LC; in Jkg-1stroke-1), representing the cost of moving the flukes, revealed that LC during routine swimming increased with body mass (M) for odontocetes according to LC=1.46±0.0005M; a separate relationship described LC during high-speed stroking. Using these relationships, we found that continuous stroking coupled with reduced glide time in response to oceanic noise resulted in a 30.5% increase in metabolic rate in the beaked whale, a deep-diving odontocete considered especially sensitive to disturbance. By integrating energetics with swimming behavior and dive characteristics, this study demonstrates the physiological consequences of oceanic noise on diving mammals, and provides a powerful tool for predicting the biological significance of escape responses by cetaceans facing anthropogenic disturbances.

Seabird diving behaviour reveals the functional significance of shelf-sea fronts as foraging hotspots.

Oceanic fronts are key habitats for a diverse range of marine predators, yet how they influence fine-scale foraging behaviour is poorly understood. Here, we investigated the dive behaviour of northern gannets Morus bassanus in relation to shelf-sea fronts. We GPS (global positioning system) tracked 53 breeding birds and examined the relationship between 1901 foraging dives (from time-depth recorders) and thermal fronts (identified via Earth Observation composite front mapping) in the Celtic Sea, Northeast Atlantic. We (i) used a habitat-use availability analysis to determine whether gannets preferentially dived at fronts, and (ii) compared dive characteristics in relation to fronts to investigate the functional significance of these oceanographic features. We found that relationships between gannet dive probabilities and fronts varied by frontal metric and sex. While both sexes were more likely to dive in the presence of seasonally persistent fronts, links to more ephemeral features were less clear. Here, males were positively correlated with distance to front and cross-front gradient strength, with the reverse for females. Both sexes performed two dive strategies: shallow V-shaped plunge dives with little or no active swim phase (92% of dives) and deeper U-shaped dives with an active pursuit phase of at least 3 s (8% of dives). When foraging around fronts, gannets were half as likely to engage in U-shaped dives compared with V-shaped dives, independent of sex. Moreover, V-shaped dive durations were significantly shortened around fronts. These behavioural responses support the assertion that fronts are important foraging habitats for marine predators, and suggest a possible mechanistic link between the two in terms of dive behaviour. This research also emphasizes the importance of cross-disciplinary research when attempting to understand marine ecosystems.

Dive characteristics can predict foraging success in Australian fur seals (Arctocephalus pusillus doriferus) as validated by animal-borne video.

ABSTRACTDive characteristics and dive shape are often used to infer foraging success in pinnipeds. However, these inferences have not been directly validated in the field with video, and it remains unclear if this method can be applied to benthic foraging animals. This study assessed the ability of dive characteristics from time-depth recorders (TDR) to predict attempted prey capture events (APC) that were directly observed on animal-borne video in Australian fur seals (Arctocephalus pusillus doriferus, n=11). The most parsimonious model predicting the probability of a dive with ≥1 APC on video included only descent rate as a predictor variable. The majority (94%) of the 389 total APC were successful, and the majority of the dives (68%) contained at least one successful APC. The best model predicting these successful dives included descent rate as a predictor. Comparisons of the TDR model predictions to video yielded a maximum accuracy of 77.5% in classifying dives as either APC or non-APC or 77.1% in classifying dives as successful verses unsuccessful. Foraging intensity, measured as either total APC per dive or total successful APC per dive, was best predicted by bottom duration and ascent rate. The accuracy in predicting total APC per dive varied based on the number of APC per dive with maximum accuracy occurring at 1 APC for both total (54%) and only successful APC (52%). Results from this study linking verified foraging dives to dive characteristics potentially opens the door to decades of historical TDR datasets across several otariid species.

The effects of SCUBA diving on the endemic Mediterranean coral Astroides calycularis

Many papers have dealt with the impact of diving activities, although most have been focussed on divers' physical contact and their equipment. Nevertheless, there are more factors that may be affecting the benthic community, for example, environment, diver's behaviour, dive characteristics, or previous knowledge of the diver about the surrounding wildlife. In the present study, several factors have been studied that may affect the orange coral (Astroides calycularis) populations in the North Alborán Sea (Mediterranean Sea). It has been demonstrated that detached colonies are more common in an impacted station than in a controlled station. However, larger sized detached colonies were found in the controlled station, which is probably due to the species growing without impact factors until they reach a size that they become detached naturally. Dimensions studied such as characteristics of dives, diver experience, environmental perception, or previous knowledge of divers are affecting at the endangered orange coral, showing that the characteristics of dives is a more noteworthy dimension. But this, in synergy with other factors, may be the cause of losing colonies. The results of this study are helpful to the managers of marine environment and MPAs, especially where sensitive species are present during diving activities. Therefore, essential diver education programmes must teach the environmental value and the fragility of different species. Protecting these populations should be a high priority of the environment managers to preserve our natural heritage.

Gas exchange and dive characteristics of the free-swimming backswimmer Anisops deanei.

Many aquatic insects utilise air bubbles on the surface of their bodies to supply O2 while they dive. The bubbles can simply store O2, as in the case of an 'air store', or they can act as a physical 'gas gill', extracting O2 from the water. Backswimmers of the genus Anisops augment their air store with O2 from haemoglobin cells located in the abdomen. The O2 release from the haemoglobin helps stabilise bubble volume, enabling backswimmers to remain near neutrally buoyant for a period of the dive. It is generally assumed that the backswimmer air store does not act as a gas gill and that gas exchange with the water is negligible. This study combines measurements of dive characteristics under different exotic gases (N2, He, SF6, CO) with mathematical modelling, to show that the air store of the backswimmer Anisops deanei does exchange gases with the water. Our results indicate that approximately 20% of O2 consumed during a dive is obtained directly from the water. Oxygen from the water complements that released from the haemoglobin, extending the period of near-neutral buoyancy and increasing dive duration.

Effects of a Fact-finding Survey on General Characteristics of Shell-fishing Work and Farm Work, Musculoskeletal Pain and Depression on Quality of life in Jeju Women Diver

The purpose of this research was to find out the effects on quality of life according to fact-finding characteristics of shell-fishing diving work, farm work, body part-specific musculoskeletal pain and depression of Jeju woman diver (haenyeo) with chronic musculoskeletal disease. Data were 199 haenyeos between 50 and 90 years old residing in S city, Jeju island. dependent variable of multiple regression is Received (May 26, 2015), Review Request(May 27, 2015), Review Result(June 10, 2015) Accepted(July 02, 2015), Published(August 31, 2015) 697-864 Dept. Physical Therapy, Seogwipo Medical Center, Jangsoo 47, Seogwipo, Jeju, Korea email: Kohw0925@hanmail.net (Corresponding Author) 506-706 Dept. Physical Therapy, Nambu University, Chumdan 23, Gwangsangu, Gwangju, Korea email: geriatricpt1@naver.com 697-864 Dept. Hyperbaric Oxygen Therapy, Seogwipo Medical Center, Jangsoo 47, Seogwipo, Jeju, Korea email: Emtyangyohan@gmail.com 682-715 Dept. Physical Therapy, Ulsan College, Bongsoo 101, Donggu, Ulsan, Korea email: cykim@uc.ac.kr Effects of a Fact-finding Survey on General Characteristics of Shell-fishing Work and Farm Work, Musculoskeletal Pain and Depression on Quality of life in Jeju Women Diver Copyright c 2015 HSST 236 quality of life, independent variables are general characteristics, shell-fishing diving work characteristics, farm working characteristics, body part-specific musculoskeletal pain, depression. general characteristics showed significant difference in 'educational level', 'living with whom' index from multiple regression analysis. shell-fishing diving work characteristics showed significant difference in 'career of diving', 'medications' index from multiple regression analysis. farm working characteristics showed significant difference in 'type of farming', 'career of farm working' index from multiple regression analysis. 'depression' index also showed significant difference from multiple regression analysis. Based on the data of this research, A systematic controls are needed continuously to improve Quality of life in jeju women divers. Keyword : haenyeo, musculoskeletal pain, depression, quality of life, multiple regression analysis.

Diel diving behavior of breeding gentoo penguins on King George Island in Antarctica

Many marine birds dive to catch prey in water. The gentoo penguin (Pygoscelis papua), a specialized diving seabird that preys on krill and fish, is distributed from the sub-Antarctic islands to Antarctic regions. Here, we observed the diving behavior of breeding gentoo penguins on King George Island, South Shetland Islands, Antarctica. Using a time–depth recorder, we collected diving depths every second from seven gentoo breeders for 5–21 days during the chick-rearing period and analyzed their diving characteristics. Most dives occurred in shallow water, although the dive efficiency (=bottom duration time/[dive duration + post-dive surface time]) was highest at depths of 30–35 m and decreased as the penguins dove deeper. Gentoo penguins did not dive more frequently during the day than at night, but during nighttime, most dives occurred in shallow water (<20 m) and the dive efficiency was also higher at this time. As penguins repeated their foraging trips, the number of dives, depth of dives, and trip duration did not change significantly. Our results suggest that the diel dive patterns of gentoo penguins might be related to the vertical migration of krill (upward to the surface at night). In addition, we observed that gentoo penguins could perform active diving behavior even at night, possibly aided by civil twilight during the chick-rearing period in Antarctic regions.