Leszek Karczmarski

Cetacea Research Institute, Hong Kong · School of Biological Sciences

Spinner dolphins (Stenella longirostris) commonly use inshore island and atoll habitats for daytime rest and social interactions and forage over deep waters at night. In Hawaii, they occur throughout the archipelago. We applied photoidentification mark-recapture techniques to study the population structure of spinner dolphins associated with remote...

Spinner dolphins (Stenella longirostris) exhibit different social behaviours at two regions in the Hawaiian Archipelago: off the high volcanic islands in the SE archipelago they form dynamic groups with ever-changing membership, but in the low carbonate atolls in the NW archipelago they form long-term stable groups. To determine whether these envir...

Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting Hong Kong waters are thought to be among the world's most anthropogenically impacted coastal delphinids. We have conducted a 5-year (2010–2014) photo-ID study and performed the first in this region comprehensive mark-recapture analysis applying a suite of open population models and robust...

Defining demographic and ecological threshold of population persistence can assist in informing conservation management. We undertook such analyses for the Indo-Pacific humpback dolphin (Sousa chinensis) in the Pearl River Delta (PRD) region, southeast China. We use adult survival estimates for assessments of population status and annual rate of ch...

A bstract This paper examines environmental and behavioral determinants of the habitat use and preferences of Indo‐Pacific humpback dolphins inhabiting the Algoa Bay region on the south Eastern Cape coast of South Africa. In order to quantify the habitat use and preference, two indices were used, the Coefficient of Area Use (AU) and the Activity In...

In fast-developing regions, rapid coastal urbanization has led to considerable transformation of both landscapes and seascapes, with various adverse implications for species dependent on inshore habitats. As reliable estimates of vital demographic rates reflect the population-level responses to stressors, rigorous quantification of these parameters...

Context Habitat selection is a fundamental process that shapes animal spatial ecology. Species with wide geographic distribution that occupy diverse habitats have to adapt their resource acquisition strategies to maximise their effectiveness under local ecological constraints, leading to intraspecific behavioural variability. Identifying environmen...

The Pearl River Delta (PRD) region on the southeast coast of China is among the largest and most populated metropolitan regions of the world, subjecting the Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting coastal waters of this region – apparently the largest population of this species – to intense anthropogenic pressure. In this 5-year...

Understanding the population history of wide-ranging species, especially those ranging over varying landscapes, helps in deciphering the evolutionary force (s) that shaped the present genetic diversity/structure of regional fauna. In the shelf region, evolution of coastal morphology through glacial oscillations played an important role in shaping t...

Quantifying demographic parameters and patterns of social dynamics is fundamental to understanding the population ecology of group-living animals and carries considerable conservation implications. In the Pearl River Delta (PRD) region, one of the world’s largest, most urbanised and industrialised estuarine systems located on the southeast coast of...

Accurate estimates of demographic parameters are instrumental in effective management of animal populations. For species with individually distinctive features, photo-identification (photo-ID) provides a reliable means to gather capture–recapture data for population parameter estimation with considerable precision and accuracy. We use a 3-year phot...

Reliable identification of individuals plays an important role in behavioural studies of free-ranging animal populations. In field studies of elephants, the naturally acquired markings on their ears, such as notches, tears and holes, are frequently used for individual identification. Although not as easily discernible from a distance as ear marking...

The Pearl River Delta (PRD) region on the southeast coast of China has long been known as a highly productive fishing ground. Since the late 1980s, fishing pressure in the PRD has been intense, which warrants concerns of potential fishery-related impacts on the food resources and foraging ecology of apex marine predators in this region, such as the...

Prey increase vigilance to maximize predator detection, but this comes at the expense of foraging depending on the vigilance type: (1) intense vigilance, when all feeding processes are ceased, and (2) routine vigilance, when animals continue chewing (i.e. lower foraging cost). Few studies have distinguished between vigilance types when examining th...

Indo‐Pacific humpback dolphins (Sousa chinensis) inhabit shallow coastal waters of the Indo‐Pacific region including southeast China, with at least six putative populations identified to date in Chinese waters. However, the connectivity among these populations has not yet been investigated. In the present study, we compared and cross‐matched photog...

Speciation is a fundamental process in evolution and crucial to the formation of biodiversity. It is a continuous and complex process, which can involve multiple interacting barriers leading to heterogeneous genomic landscapes with various peaks of divergence among populations. In this study, we used a population genomics approach to gain insights...

Humpback dolphins (genus Sousa), obligatory inshore delphinids, are frequently exposed to adverse effects of many human activities. In Hong Kong, one of the world’s most urbanised coastal regions, ~ 50% of the dolphins suffer from at least one type of epidermal lesions, likely related to anthropogenically degraded habitat. Furthermore, one in every...

1. The finless porpoise (genus Neophocaena) is susceptible to fishery‐caused mortality, and its numbers are thought to be in decline across its entire range. However, population demographics have rarely been quantified for this genus, with a few exceptions of the narrow‐ridged form (Neophocaena asiaeorientalis) in waters off Japan, Korea, and in th...

Early studies of Chinese white dolphins applied primarily line-transect survey techniques to acquire distribution data and generate abundance estimates, while many recent studies rely on mark-recapture techniques to gain insights into population dynamics and demography. The application of an individual photo-identification approach provides the mea...

Optimal resource selection is crucial for maximising fitness and survival. Animals introduced to a new area need time to explore the environment, which could result in a time lag before optimal selection occurs. Furthermore, intra‐specific interactions (particularly in territorial species) also play a role in shaping resource selection patterns, wi...

Award: Best Doctoral Poster Presentation / Keywords: Sousa chinensis; Pearl River Estuary; mark-recapture analysis; socio-demographic models; ecological and demographic thresholds

Very little is known of the spatio-behavioural dynamics of island-associated cetaceans, and even less so about multi-species communities such as those seen in Tañon Strait, central Philippines. Declared as a protected seascape in 1998, Tañon Strait is a semi-enclosed body of water characterized by a narrow coastal zone and considerable depths relat...

The finless porpoise (genus Neophocaena) is a poorly known cetacean of great conservation concern. Within its range, from western Pacific to northwestern Indian Ocean, there are currently two species recognized (N. asiaeorientalis and N. phocaenoides), thought to be reproductively isolated since last glacial maximum, with the only sympatric overlap...

Understanding of animal spatial behavior is essential for informed management decisions. In southern Africa, reintroduction of lions (Panthera leo) to small reserves (<1000 km2) has increased in recent years but studies on their ranging behavior in these enclosed systems remain lacking. We applied Time Local Convex Hull (T-LoCoH) methods to study t...

Prey species of humpback dolphins in Pearl River Estuary and their annual peak of abundance in Hong Kong waters. (DOCX)

For the Indo-Pacific humpback dolphin, Sousa chinensis, an obligatory shallow-water inshore species, the degradation of coastal habitats can have major consequences for population persistence and distribution. Off Taiwan's west coast (TWC), these animals are predominantly seen in two areas separated by a stretch of coast with only sporadic sighting...

We assessed the spatio-temporal trends of the concentrations of 11 heavy metals (HMs) in the liver and kidney of Indo-Pacific humpback dolphins (Sousa chinensis) from western Pearl River Estuary (PRE) during 2004-2015. The hepatic levels of Cr, As and Cu in these dolphins were among the highest reported for cetaceans globally, and the levels of Zn,...

Over the past few thousand years, human development and population expansion in southern China have led to local extirpation and population contraction of many terrestrial animals. At what extent this early human-induced environmental change has also affected coastal marine species remains poorly known. We investigated the demographic history of th...

Previous sightings of bottlenose dolphins in Tañon Strait, central Philippines, in the late 1980’s to early 1990’s were limited to the southern section of the strait, in waters <500 m deep, and the species was formerly identified as Tursiops truncatus. Photo-identification surveys (n = 117) conducted in 2014 and 2015 in Tañon Strait resulted in 50...

Previous sightings of bottlenose dolphins in Tañon Strait, central Philippines, in the late 1980’s to early 1990’s were limited to the southern section of the strait, in waters <500 m deep, and the species was formerly identified as Tursiops truncatus. Photo-identification surveys (n = 117) conducted in 2014 and 2015 in Tañon Strait resulted in 50...

Infanticide has been observed in several mammalian taxa and studied in considerable detail in carnivores and primates. Although reported previously in cetaceans, known cases are few and their socio-behavioral context remains poorly understood. We report here on three cases of social coercion directed at mother-neonate pairs of Indo-Pacific humpback...

Coastal dolphins are more prone to cumulative impacts of environmental and anthropogenic changes than pelagic species. However, few studies use historical comparisons to evaluate those impacts across a temporal scale. The study presented here describes the pattern of occurrence, group size, behavior, and habitat use of humpback dolphins in Algoa Ba...

The continuous disposal of persistent organic pollutants (POPs) in South Africa (SA) warrants concern about their detrimental effects on humans and wildlife. We surveyed six dolphin species (n=90) incidentally captured in shark net installations or stranded off the SA east and south coast from 2005 to 2009 to study the POP exposure. Sousa plumbea,...

In coastal waters of the Pearl River Delta (PRD) region, the Indo-Pacific humpback dolphin (Sousa chinensis) is thought to number approximately 2500 individuals. Given these figures, the putative PRD population may appear strong enough to resist demographic stochasticity and environmental pressures. However, living in close proximity to the world's...

Conference poster

Reintroductions have been increasingly used in carnivore conservation. Animal movement influences fitness and survival and is the first behavioural response of reintroduced animals to ‘forced dispersal’ in a new habitat. However, information available on early post-release movement of reintroduced carnivores remains limited. We studied movements of...

In coastal waters of the Pearl River Delta (PRD) region, the Indo-Pacific humpback dolphin (Sousa chinensis) is thought to number approximately 2500 individuals. Given these figures, the putative PRD population may appear strong enough to resist demographic stochasticity and environmental pressures. However, living in close proximity to the world's...

Predictive modeling of population trends can indicate the rate of population decline and risk of extinction, providing quantitative means of assessing conservation status and threats. Our study tests the rate of population change and risk of extinction of the Indo-Pacific humpback dolphin Sousa chinensis off the west coast of Taiwan, the only humpb...

We used 344 mitochondrial control region (717 bp) sequences from the finless porpoise (genus Neophocaena) from the northwestern Pacific to investigate the extent and manner in which past climatic oscillations may have shaped patterns of genetic diversity for this marine mammal. Both SplitsTree and Analysis of Molecular Variance (AMOVA) revealed the...

Much of the knowledge about the wide-ranging finless porpoise species (Neophocaena phocaenoides) remains limited, as well as its phylogenetic relationship with another taxa (N. asiaeorientalis) in genus Neophocaena. Using 11 microsatellite loci, we first investigated population differentiation of N. phocaenoides within the Pearl River Estuary (PRE)...