The Istanbul Strait is an important cetacean habitat that is intensely used by humans. Yet little is known about their spatial-temporal distribution. To understand the encounter rates and residency patterns of bottlenose dolphins, photo-identification data were collected between 2011 and 2016 in the Istanbul Strait. The study showed that bottlenose dolphins are a regular, year-round component of the strait. The encounter rate was estimated to be four groups (22 individuals) per 10 km. The adjacent waters of Marmara Sea and Black Sea, that host relatively less marine traffic, had the highest number of encounters in the area. Conversely, the middle sections had the lowest number of encounters but the highest marine vessel density. Further, the encounter rates dropped to zero in the fishing zones, where the number of purse seines reached up to 100 per day. Additionally, dolphins showed varying degrees of residency patterns, with multi-year re-sightings. Maximum re-sighting distance was up to 35 km, which is more than the total length of the strait. This movement pattern should be investigated as it might reveal possible migration between local populations. This study finds that the Istanbul Strait serves as a critical habitat for the regional bottlenose dolphin populations and they are likely to be a part of a resident local population with a home range extending the length of the strait. Dedicated surveys with inter-regional collaborations are needed to evaluate the home range and population status of this endangered species for their effective conservation in one of the busiest waterways of the world.

This article develops a market timing decision rule for cattle feeders based on profit maximization. We then compare it with the “status quo” strategy of feeding cattle to a targeted carcass end point. We estimate individual nonlinear dynamic growth functions to derive each animal's value of the marginal product in relation to days on feed. Given individual marginal factor costs, our results indicate that the use of a profit maximization rule could have increased average profits by $16.56 to $21.09 per head for the cattle of known age, and $7.67 to $11.32 per head if age was unknown.

China is home to three subspecies of tiger Panthera tigris but there are no estimates of the size of any of the populations. We detected a population of the Endangered Amur tiger Panthera tigris altaica in Hunchun Nature Reserve in Jilin Province using both mitochondrial DNA and nuclear microsatellite loci. Four male and one female tigers were detected, indicating the potential for a small breeding group. However, genetic diversity was low overall, with six loci showing a heterozygote deficiency and a mean of 2.55 alleles per locus. This study is the first estimate of the wild Amur tiger population in China to use non-invasive techniques, and the presence of a female tiger indicates this is a potentially viable population. We provide baseline genetic diversity estimates to support monitoring of the population. The small number of tiger scats located indicates the importance of continuing the current conservation efforts for this tiger subspecies in Hunchun Nature Reserve. Such efforts include reducing poaching of tigers and their prey, and implementation of management plans to encourage the persistence and recovery of tigers in this area.

Individual identification using Hi8 video images was tested on the population of estuarine dolphins, Sotalia guianensis that inhabit the Cananéia estuary, south-eastern Brazil. Between June 2001 and August 2002, 25 different dolphins were identified by nicks on the dorsal fin (80%) and by the association of cuts and scratches on the dorsal fin and the body's dorsal region (20%). The existent marks were used to create an identification key to ease the matching between dolphins. The animals were present on 100% of the sampled days, and some of them were repeatedly registered at the same sector in the area, suggesting that although they occupy an extensive area, they use it in an intended way. When compared to researches that used photographs to identify cetaceans, the video images showed some loss of information, nevertheless the analysis could be done without impairment of results, therefore this method proved to be efficient.

An objective multivariate technique is described for identification of individual tigers Panthera tigris from their pugmarks. Tracings and photographs of hind pugmarks were obtained from 23 pugmark-sets of 19 individually known tigers (17 wild and two captive tigers). These 23 pugmark-sets were then divided into two groups, one of 15 pugmark-sets for model building and another of eight pugmark-sets for model testing and validation. A total of 93 measurements were taken from each pugmark along with three gait measurements. We used CV ratio, F-ratio and removed highly correlated variables to finally select 11 variables from these 93 variables. These 11 variables did not differ between left and right pugmarks. Stepwise discriminant function analysis (DFA) based on these 11 variables correctly classified pugmark-sets to individual tigers. A realistic population estimation exercise was simulated using the validation dataset. The algorithms developed here correctly allocated each pugmark-set to the correct individual tiger. The effect of extraneous factors, i.e. soil depth and multiple tracers, was also tested and pugmark tracings compared with pugmark photographs. We recommend collecting pugmarks from soil depths ranging between 0.5 and 1.0 cm, and advocate the use of pugmark photographs rather than pugmark tracings to eliminate the chance of obtaining substandard data from untrained tracers. Our study suggests that tigers can be individually identified from their pugmarks with a high level of accuracy and pugmark-sets could be used for population estimation of tigers within a statistically designed mark–recapture framework.

Evidence for individuality of odour profile, coding for individual identity, was sought in scent profiles derived from natural secretions of the preorbital gland of red deer Cervus elaphus (n = 26), sika deer C. nippon (15), fallow deer Dama dama (50), Chinese muntjac Muntiacus reevesi (23) and Chinese water deer Hydropotes inermis (53); from metatarsal secretions from red deer (n = 35), sika (30), fallow (193) and roe deer Capreolus capreolus (26), and from roe deer interdigital glands (n = 48). Volatiles were eluted from sample materials at body temperature, to restrict analysis to those elements that would occur within the natural odour signal; the different volatile elements were then separated by gas chromatography. For each species considered, secretions from at least one scent gland were individually distinct and sufficiently complex to code for identity. Within our samples no two individuals produced identical odour profiles; yet in analysis of metatarsal gland secretions of individual fallow deer sampled in successive years, odour signatures of individuals remained consistent over time. The wider potential for individual coding was assessed through calculation of the number of different possible combinations of all volatiles recovered in any species×gland system. Every secretion considered seems to have the potential to provide individually characteristic signals (with the exception of secretions from the fallow deer preorbital gland, which notably contained no odour information under any analytical system). Complexity of signals differed markedly between species as did the gland-type responsible for production of the most complex or distinctive signal. No simple evolutionary patterns are apparent to account for this variation and we suggest that the form of gland selected for production of a signal carrying information about individual identity is a function of habitat type and sociality.