RIGHT WHALES (EUBALAENA GLACIALIS) ON JEFFREYS LEDGE: A HABITAT OF UNRECOGNIZED IMPORTANCE?

North Atlantic right whales ( Eubalaena glacialis ) are known to spend the majority of the year between the Great South Channel southeast of Cape Cod, and the Nova Scotian shelf. We examined sightings of right whales on and around Jeffreys Ledge, a 54-km-long glacial deposit off the coast of northern Massachusetts, New Hampshire, and Maine. Sightings on Jeffreys Ledge were extracted from three data sets: (1) a systematic survey of the entire northeastern continental shelf between 1979 and 1982, (2) whale-watch and research-cruise sighting data from 1984 to 1997, and (3) a collaborative database of sightings collected by organizations conducting right whale research and all other available sources. Each database supported two seasonal sighting peaks. During summer (especially July and August) sightings were primarily of mother-calf pairs. Several cow-calf pairs were seen over several days to weeks. Several females were resighted in more than one year, but only when calves were present. During October, November, and December, sightings included all age classes, surface-feeding behavior was frequently observed, and some animals were resighted over several weeks. Given the relatively reduced sighting effort during fall, this number of sightings is surprising. During the 20 yr of observations, 52 of 374 photo-identified North Atlantic right whales (13.9%) were seen at least once on Jeffreys Ledge. We suggest that Jeffreys Ledge may be a more important right whale habitat than previously believed, and that it may play an important role in annual movements and distribution of this population.     

Passive acoustic monitoring predicts daily variation in North Atlantic right whale presence and relative abundance in Roseway Basin,Canada

North Atlantic right whale monitoring in Roseway Basin, Canada, is primarily based on short‐term (<14 d) visual surveys conducted during August–September. Variability in survey effort has been the biggest limiting factor to studying changes in the population's occurrence and habitat use. Such efforts could be enhanced considerably using passive acoustic monitoring (PAM). We sought to determine if variation in whale presence, relative abundance, demography, and/or behavior (estimated through visual surveys) could be explained by variation in three right whale call types in this habitat. A generalized linear model was fit to 23 d of concurrent PAM and visual monitoring during four summers within the Roseway Basin Right Whale Critical Habitat boundaries. The model revealed significant positive relationships between relative abundance, call counts and presence of surface‐active group behavior. PAM can refine daily right whale presence estimates. While visual observations (n = 23 d) implied a 40% decline in right whale presence during 2014–2015 relative to 2004–2005, PAM data (n = 211 d) showed right whales were present between 71%–85% of survey days throughout all years analyzed. We demonstrate that PAM is a useful tool to extend periods of right whale monitoring, especially in areas where visual monitoring efforts may be limited.     

Killer whales (Orcinus orca) in the Canadian Arctic: Distribution,prey items,group sizes,and seasonality

Killer whales (Orcinus orca) have a global distribution, but many high‐latitude populations are not well studied. We provide a comprehensive review of the history and ecology of killer whales in the Canadian Arctic, for which there has previously been little information. We compiled a database of 450 sightings spanning over 15 decades (1850–2008) to document the historical occurrence, distribution, feeding ecology, and seasonality of killer whales observed throughout the region. Sighting reports per decade increased substantially since 1850 and were most frequent in the eastern Canadian Arctic. The mean reported group size was 8.3 (median = 4, range 1–100), but size varied significantly among regions and observed prey types. Observations of predation events indicate that Canadian Arctic killer whales prey upon other marine mammals. Monodontids were the most frequently observed prey items, followed by bowhead whales (Balaena mysticetus), phocids, and groups of mixed mammal prey. No killer whale sightings occurred during winter, with sightings gradually increasing from early spring to a peak in summer, after which sightings gradually decreased. Our results suggest that killer whales are established, at least seasonally, throughout the Canadian Arctic, and we discuss potential ecological implications of increased presence with declining sea ice extent and duration.     

Sighting frequency decreases over two decades in three populations of Testudo hermanni from central Italy

Sighting frequency of tortoises (Testudo hermanni), standardized by the number of person-hours of field effort, was studied between 1992 and 2013 at three different study areas in central Italy. Although the frequency of tortoise sightings fluctuated substantially across years and among study areas, there was a significant declining trend in all the three areas, with GLM analyses showing also a significant interaction between study area and sampling year. The decreasing trend was higher in Castel Fusano than in the other two sites, with yearly frequency of sightings being independent of search effort in all of the study areas. These trends may indicate population declines, because no other explanations seem plausible. Total rainfall from previous autumn to the study period was positively correlated to tortoise sightings in only one locality. The yearly frequency of sightings of juvenile tortoises did not vary significantly among study areas and across years, thus indicating that simple differences in detectability cannot explain the observed patterns. Summer fires and forest overgrowing seem to explain the tortoise decline in two study areas (Castel Fusano and Oriolo) whereas we were not able to identify any specific reason for tortoise decline in the third study area (Manziana).     

Predicting the distribution of Sasquatch in western North America: anything goes with ecological niche modelling

The availability of user-friendly software and publicly available biodiversity databases has led to a rapid increase in the use of ecological niche modelling to predict species distributions. A potential source of error in publicly available data that may affect the accuracy of ecological niche models (ENMs), and one that is difficult to correct for, is incorrect (or incomplete) taxonomy. Here we remind researchers of the need for careful evaluation of database records prior to use in modelling, especially when the presence of cryptic species is suspected or many records are based on indirect evidence. To draw attention to this potential problem, we construct ENMs for the North American Sasquatch (i.e. Bigfoot). Specifically, we use a large database of georeferenced putative sightings and footprints for Sasquatch in western North America, demonstrating how convincing environmentally predicted distributions of a taxon's potential range can be generated from questionable site-occurrence data. We compare the distribution of Bigfoot with an ENM for the black bear, Ursus americanus , and suggest that many sightings of this cryptozoid may be cases of mistaken identity.     

Meals on Wheels? A Decade of Megafaunal Visual and Acoustic Observations from Offshore Oil & Gas Rigs and Platforms in the North and Irish Seas

A decade of visual and acoustic detections of marine megafauna around offshore Oil & Gas (O&G) installations in the North and Irish Seas are presented. Marine megafauna activity was monitored visually and acoustically by Joint Nature Conservation Committee (JNCC) qualified and experienced Marine Mammal Observers (MMO) and Passive Acoustic Monitoring (PAM) Operators respectively, with real-time towed PAM in combination with industry standard software, PAMGuard. Monitoring was performed during routine O&G industrial operations for underwater noise mitigation purposes, and to ensure adherence to regulatory guidelines. Incidental sightings by off-effort MMOs and installation crew were also reported. Visual and acoustic monitoring spanned 55 non-consecutive days between 2004 and 2014. A total of 47 marine mammal sightings were recorded by MMOs on dedicated watch, and 10 incidental sightings of marine megafauna were reported over 10 years. Species included: harbour porpoise (Phocoena phocoena), Atlantic white-sided dolphin (Lagenorhynchus acutus), white beaked dolphin (Lagenorhynchus albirostris), common dolphin (Delphinus delphis), minke whale (Balaenoptera acutorostrata), common seal (Phoca vitulina), grey seal (Halichoerus grypus) and, basking shark (Cetorhinus maximus). Passive Acoustic Monitoring was conducted on two occasions in 2014; 160 PAM hours over 12 days recorded a total of 308 individual clicks identified as harbour porpoises. These appear to be the first such acoustic detections obtained from a North Sea drilling rig whilst using a typically configured hydrophone array designed for towing in combination with real-time PAMGuard software. This study provides evidence that marine megafauna are present around mobile and stationary offshore O&G installations during routine operational activities. On this basis, Environmental Impact Assessments (EIAs) for decommissioning O&G platforms should be carried-out on a case-by-case basis, and must include provisions for hitherto overlooked marine megafauna.     

AERIAL SURVEYS FOR COASTAL DOLPHINS: ABUNDANCE OF HECTOR'S DOLPHINS OFF THE SOUTH ISLAND WEST COAST, NEW ZEALAND

Line-transect surveys of abundance depend critically on the estimation of detection probability, which includes corrections for availability and visibility. In this aerial line-transect survey for Hector's dolphin ( Cephalorhynchus hectori ) we recorded dive times from a helicopter to estimate the proportion of time that dolphins could be seen at or near the water surface and were therefore "available" to be counted. The proportion of available sightings that were counted on transect lines was estimated by comparing sightings by two independent teams of two observers in the fixed-wing plane. The survey covered the area between Farewell Spit and Milford Sound, off the west coast of the South Island of New Zealand. Survey effort was stratified according to existing distribution data. A total of 142 separate sightings was made on 1,355 km of trackline. Average availability for fifty Hector's dolphin groups observed from the helicopter (161 dive/surface cycles) was 46.3% (CV = 4.2%). Data from the two independent observer teams indicated that 96.2% (CV = 2.3%) of the dolphin groups that were at the surface and on the trackline were seen. The abundance estimate for the South Island west coast, corrected for visibility and availability, was 5,388 Hector's dolphins (CV = 20.6%). The total population estimate for South Island Hector's dolphins is 7,270 (CV = 16.2%).     

Historic and current habitat use by North Pacific right whales Eubalaena japonica in the Bering Sea and Gulf of Alaska

1. To help define areas and ecological parameters critical to the survival and recovery of the remnant population of North Pacific right whales, habitat use was investigated by examining all available sighting and catch records in the south-eastern Bering Sea (SEBS) and Gulf of Alaska (GOA) over the past two centuries. 2. Based on re-analyses of commercial whaling records, search effort, and resultant catches and sightings, waters of the: (i) SEBS slope and shelf, (ii) eastern Aleutian Islands and (iii) GOA slope and abyssal plain were important habitat for North Pacific right whales through the late 1960s. 3. Since 1980, the only area where right whales have been seen consistently is on the SEBS middle shelf. However, acoustic detections and single sightings have been reported in all other regions except the SEBS slope and oceanic GOA (areas where little, if any, acoustic and visual effort has occurred). 4. Sightings since 1979 were in waters < 200 m deep which may simply reflect the paucity of search effort elsewhere. From the commercial whaling era to the late 1960s, right whales were commonly seen in waters > 2000 m deep, indicating that their distribution is not restricted to shallow continental shelves. 5. North Pacific right whale sightings through the centuries have been associated with a variety of oceanic features, and there is little in common in the bathymetry of these regions. These whales appear to have a greater pelagic distribution than that observed in the North Atlantic, which may be related to the availability of larger copepods across the SEBS and GOA.     

Steller sea lion spatial‐use patterns derived from a Bayesian model of opportunistic observations

Despite acquisition of a substantial catalog of telemetry data from Steller sea lions (Eumetopias jubatus) over the past two decades, scientists still lack comprehensive regionally explicit knowledge about Steller sea lion habitat use. The Platforms of Opportunity data contain records of Steller sea lion sightings throughout the species’ entire range and have potential to fill gaps in knowledge about their spatial use; however, the data have not previously been used because effort (e.g., time spent surveying or area sampled) was not recorded when sightings were obtained. For this study a novel approach was used to overcome the lack of effort data through development of an effort index and a Bayesian negative binomial model. The model quantified Steller sea lion encounter rates and associated uncertainty within 15 × 15 km² grid cells across the species’ entire range. Year‐round, as well as breeding and nonbreeding season encounter rates were estimated. The results of this analysis identify several previously undocumented areas of high use by Steller sea lions, indicate that only 37% of Steller sea lion high‐use areas fall within designated critical habitat, and demonstrate that use of depth and distance from shore as indicators of Steller sea lion habitat is contraindicated.     

ESTIMATES OF SPERM WHALE ABUNDANCE IN THE NORTHEASTERN TEMPERATE PACIFIC FROM A COMBINED ACOUSTIC AND VISUAL SURVEY

We estimate the abundance of sperm whales in a 7.8 million km² study area in the eastern temperate North Pacific using data from a ship-based acoustic and visual line-transect survey in spring 1997. Sperm whales were detected acoustically using a hydrophone array towed at 15 km/h and 100 m depth. The hydrophone array was towed for 14,500 km, and locations were estimated acoustically for 45 distinct sperm whale groups. Whales producing slow clicks (>2-s period) were detected at greater distance (up to 37 km), and the estimation of effective strip widths was stratified based on initial click period. Visual survey effort (using 25° binoculars and naked eyes) covered 8,100 km in Beaufort sea states 0–5 and resulted in only eight sightings. The effective strip width for visual detections was estimated from previous surveys conducted using the same methods and similar vessels in the eastern Pacific. Estimated sperm whale abundance in the study area was not significantly different between acoustic (32,100, CV = 0.36) and visual (26,300, CV = 0.81) detection methods. Acoustic techniques substantially increased the number of sperm whales detected on this line-transect survey by increasing the range of detection and allowing nighttime surveys; however, visual observations were necessary for estimating group size.     

Occurrence Patterns,Habitat Associations,and Potential Prey of the River Dolphin,Inia geoffrensis,in the Cinaruco River,Venezuela1

The distribution, habitat association, group size, population structure, and prey availability of river dolphins (Inia geoffrensis) were studied from November 1993-June 1994 in the Cinaruco River, a tributary of the Orinoco River that forms the southern boundary of Venezuela's Santos Luzardo National Park. Dolphins were sampled from a boat using modified strip-width transects, for a total of 418 h. The study area was 1.67 km², and contained 20 km of water courses. Like other rivers of this region, the Cinaruco River undergoes a seasonal flood cycle. Dolphins were seen most often during the period of falling water (41% of total sightings) and least often during the rising water period (24% of total sightings). Dolphins were seen most often in confluence areas (35% of total sightings) and were seldom seen in side channels (13% of total sightings). The presence of rocks or sandbanks was associated with a greater frequency of dolphin sightings, and sightings increased with habitat heterogeneity. Average group size for the 8-mo study was 2.0 (±1.0) and was largest during the rising water period. Calves were first sighted during the end of the dry season and became more common during the early flood season. Six individuals were photo-identified and resighted with one sighted eight times over 186 d. The fish diversity of the study area was high, with 161 species documented in our samples. The stomach of one Inia contained 15 fishes representing at least 4 species.     

Observations of bowhead whales (Balaena mysticetus) in the Svalbard area 1940–2009

Forty-six sightings of bowhead whales have been reported from the Svalbard area between 1940 and 2009. But, only three of these sightings are reported prior to 1980. Most observations involve only one or two whales, but groups of up to seven individuals have been seen recently. Increased ship traffic, particularly cruise-based tourism, in the north undoubtedly provides more opportunities for spotting this species, and the establishment of a structured cetacean sighting programme, as well as increase in effort in documenting sightings from a wider marine user-community, likely all play a role in more records being documented in recent years. The absence of a dedicated monitoring programme for ice-associated cetaceans and the generally low scientific activity level in this field in Svalbard Waters hampers firm conclusions about the trends in abundance of bowhead whales in the Svalbard area.     

A citizen science approach to long-term monitoring of humpback whales (Megaptera novaeangliae) off Sydney,Australia

The Cape Solander Whale Migration Study is a citizen science project that annually counts northward migrating humpback whales (Megaptera novaeangliae) off Cape Solander, Sydney, Australia. Dedicated observers have compiled a 20-year data set (1997–2017) of shore-based observations from Cape Solander's high vantage point. Using this long-term data set collected by citizen scientists, we sought to estimate the humpback whale population trend as it continues to recover postexploitation. We estimated an exponential growth rate of 0.099 (95% CI = 0.079–0.119) using a generalized linear model, based on observer effort (number of observation days) and number of whales observed, equating to 10% per annum growth in sightings since 1997. We found that favorable weather conditions for spotting whales off Cape Solander consisted of winds <30 km/hr from a southerly through a north westerly direction. Incidental observations of other cetacean species included the endangered blue whale (Balaenoptera musculus) and data deficient species such as killer whales (Orcinus orca) and false killer whales (Pseudorca crassidens). Citizen science-based studies can provide a cost-effective approach to monitoring wildlife over the time necessary to detect change in a population. Information obtained from citizen science projects like this may help inform policy makers responsible for State and Federal protection of cetaceans in Australian waters and beyond.     

Hunt sightings as a tool for monitoring the distribution and abundance of brown hare <Emphasis Type="Italic">Lepus europaeus</Emphasis> in UK agricultural landscapes

We examined the potential of hare sightings data, collected during hunts by the Association of Masters of Harriers and Beagles, as a possible monitoring tool for the European brown hare Lepus europaeus. The relationship between land use and both temporal trends, and spatial patterns, in brown hare sightings across England and Wales was examined using data collected between the 1985/86 and 2004/05 hunting seasons. Hare sightings increased significantly during this period, with an average increase of 2.81 hare sightings per hunting day across all hunts since 1985. Sightings were more frequent in eastern England, where arable land is abundant, than in the rest of England and Wales which is predominantly pastoral. There was no correlation between temporal trends in hare sightings and land use change. Patterns observed using the hunt sighting data are similar to those reported by other concurrent studies that used different methods. We conclude that hunt sightings could contribute useful data to a national monitoring scheme.     

BIODIVERSITY RESEARCH: When is a species really extinct? Testing extinction inference from a sighting record to inform conservation assessment

Aim The global extinction of a species typically represents the end point in a series of population extinctions, during which unique evolutionary history is lost at every stage. Insight into the process of extinction can provide the means to identify species at high risk, but the number of extinctions being identified languishes far behind true totals. More proactive ways of inferring extinction from limited data are required. Location Historic sightings, collections and specimen data from Australia and Asia. Method We used a technique called optimal linear estimation to analyse the sightings record of mammal and bird species of varying ecology, life history and population demography. The mammal species chosen were all considered regionally extinct in the literature, while the bird species chosen had all been highlighted as candidates for the new IUCN Red List category flag: Critically Endangered (Possibly Extinct). Results Nine of the ten mammal species were predicted to be probably extinct, but only two with 95% certainty. Seven of the ten bird species were predicted to be probably extinct, four with 95% certainty. Main conclusions Superficially, determining whether a species is extinct might seem a simple task, whereby we either find a species extant, or it is extinct. In reality, however, the task is much more complex. Techniques such as optimal linear estimation, in combination with other data sources, and knowledge of recording effort, may prove useful in inferring extinction across a variety of taxa but should not be used in isolation.     

REPRODUCTIVE SEASONALITY OF WESTERN ATLANTIC BOTTLENOSE DOLPHINS OFF NORTH CAROLINA, U.S.A.

We describe reproductive seasonality of bottlenose dolphins in North Carolina (NC), U.S.A., using strandings data from the entire coast of NC and sighting data from Beaufort, NC and by estimating dates of birth of known females. We found a strong peak of neonate strandings in the spring (April-May), and low levels of neonate strandings in the fall and winter. The distribution of neonate strandings was significantly different from a uniform distribution ( P < 0.001, K = 3.8). We found a unimodal distribution of 282 sightings of neonates with a diffuse peak in the summer. The temporal distribution of sightings of neonates departed significantly from a uniform distribution (P < 0.001, K = 5.1). Estimated birth dates of neonates from known females occurred in May ( n = 6) and June ( n = 4), with a single fall birth. These methods shed light on bottlenose reproductive patterns and underscore the value of using information from multiple types of data. Clarification of bottlenose dolphin reproductive patterns, such as the seasonality of birth, may enhance our understanding of the population structure of this species in the mid-Atlantic region.     

Performance of autonomous recorders to detect a cryptic and endangered primate species,the black lion-tamarin (Leontopithecus chrysopygus)

Information about species distribution is important for conservation but the monitoring of populations can demand a high sampling effort with traditional methods (e.g., line transects, sound playback) that are poorly efficient for cryptic primates, such as the black lion tamarin (Leontopithecus chrysopygus). Here we investigated the effectiveness of passive acoustic monitoring (PAM) as an alternative method to identify the presence of vocalizing lion tamarins in the wild. We aimed to: (1) determine the maximum distance at which autonomous recorders (Song Meter 3) and Raven Pro acoustic software can respectively detect and identify lion tamarin long calls emitted by two captive subjects (ex situ study); and (2) determine the sampling effort required to confirm the presence of the species in the wild (in situ study). In captive settings, we recorded lion tamarin long calls with one to two autonomous recorders operating at increasing distances from the animals' enclosure (8−202 m). In a 515 ha forest fragment, we deployed 12 recorders in a grid, 300 m apart from each other, within the estimated 100 ha home range of one group, and let them record for 10 consecutive days, totaling 985 h. In the ex situ study, hand-browsing of spectrograms yielded 298 long calls emitted from 8 to 194 m, and Raven's Template Detector identified 54.6% of them, also emitted from 8 to 194 m. In the in situ study, we manually counted 1115 long calls, and the Raven's Template Detector identified 44.75% of them. Furthermore, the presence of lion tamarins was confirmed within 1 day using four randomly sorted recorders, whereas 5 days on average were necessary with only one device. While specific protocols still need to be developed to determine primate population size using this technology, we concluded that PAM is a promising tool when considering long term costs and benefits.     

厦门水域中华白海豚出现于围头湾

厦门海域的中华白海豚是一个受威胁的种群。以往有关该种群的调查范围主要集中在厦门以及邻近的南部漳州海域。为了获得厦门岛东部海域（包括晋江围头湾、小嶝岛以及大嶝岛部分水域）白海豚的分布和数量等信息,本文于2013年6—8月对该水域进行了船基样线法调查和照相识别研究。调查期间共目击到白海豚26群,照相识别白海豚个体27头。所有照相识别的白海豚个体均与厦门中华白海豚个体识别数据库中的个体匹配,表明厦门中华白海豚的分布区至少向东延伸至围头湾。本文白海豚遇见率为5.8群/100km和24.8头/100km,均要高于以往在厦门水域的调查结果,表明大嶝岛—围头湾水域是厦门中华白海豚的重要栖息地之一,值得优先保护和管理。     

Estimating abundance for a savanna elephant population using mark–resight methods: a case study for the Tembe Elephant Park, South Africa

Elephants living in dense woodlands are difficult to count. Many elephant populations in Africa occur in such conditions. Estimates of these populations based on total counts, aerial counts and dung counts often lack information on precision and accuracy. We use standard mark–recapture field methods to obtain estimates of population size with associated confidence limits. We apply this approach to a closed elephant population in the Tembe Elephant Park (300 km²), South Africa. A registration count completed in 4 months gives a known population size. We evaluate mark–recapture models against the known population size. Individual identification profiles obtained for elephants during the registration count and mark–recapture events indicate that at least 167 elephants live in the park. We consider this value as an estimate of the minimum number alive. We include 189 sightings of bulls and 37 sightings of breeding herds in the mark–recapture modelling. Of the models we test (Petersen, Schnabel, Schumacher, Jolly–Seber, Bowden's, Poisson and negative binomial), Bowden's gives an estimate closest to the registration count. Assumptions of the model are not violated. For all models except one (negative binomial), our estimates improve with increased sampling intensity. Confidence intervals do not improve with increased effort except for the Schnabel model. Mark–recapture methods should be considered as reliable estimators of population size for elephants occurring in dense woodlands and forests when other methods cannot be relied on.