Cetacean Stranding Response Program and Spatial-Temporal Analysis in Taiwan, 1994-2018.

A national cetacean stranding response program in Taiwan has evolved significantly in the past three decades. Initially co-ordinated by National Taiwan University from 1994, the program transitioned to the Taiwan Cetacean Society in 1999, and local governments took on a more prominent role after 2009. A comprehensive stranding database (1994-2018) has been maintained, which documented 1320 stranding events involving 1698 animals from at least 27 species. The most commonly stranded species include finless porpoises, bottlenose dolphins, Kogia spp., and Risso's dolphins. The stranding rates varied annually and seasonally, with increases noted from an average of 16 events per year for the first 3 years to 44-58 events per year between 1997 and 2015, and a sharp rise to over 90 events per year for the period of the last three years. Seasonal variations were also significant, with higher stranding rates during the northeastern monsoon (NEM, October to next April) than that during southwestern monsoon (SWM, May to September). From the aspect of distribution, more frequent and even strandings occurred along the coast of northern Taiwan, while mass strandings were concentrated in the southwestern counties during NEM. Among all strandings, 390 events (29.5%) and 660 animals (38.9%) were live ones. Under great effort in rescuing and rehabilitating 52 cases, 15 cetacean individuals have been released since 2000. Additionally, there have been 56 mass strandings involving at least 11 species since 1994, predominated by pygmy killer whales, particularly during the NEM season along the southwest coast. This study not only contributes to our understanding of the stranding patterns and diversity of the cetaceans in Taiwan, but also provides valuable insights for future conservation strategies on cetaceans in the western Pacific.

Skin Marks in Critically Endangered Taiwanese Humpback Dolphins (Sousa chinensis taiwanensis).

As long-lived apex predators, Indo-Pacific humpback dolphins (Sousa chinensis) are key indicators of marine coastal environmental health. Skin marks can be observed on dorsal body surfaces that are visible during mark-recapture studies that rely on photo-identification (photo-ID) methods. Skin mark prevalence may be an indicator of environmental or anthropogenic stressors in the ecosystem, which may lead to individual and/or population-level health concerns. The prevalence of marks of anthropogenic origin was assessed in the Critically Endangered S. chinensis taiwanensis population along the coasts of central Taiwan. Fifty, twenty-eight, and thirty-four individuals were identified in 2018, 2019, and 2021, respectively. At least one category of injuries was observed in 47 of 57 distinctive individuals (82%), and adults showed a higher prevalence of deep injuries than the other coloration stages. At least one category of skin lesion was observed in 33 of 57 distinctive individuals (58%), and high prevalence of skin lesions was found in mature individuals. Given the difficulty in taking direct observations, skin mark prevalence is proposed as a proxy for estimating habitat health and anthropogenic stressors upon S. chinensis taiwanensis. The moderate-to-high prevalence of skin marks in this study was designated as a warning of risks. This study provides important updated information for the assessment of the health and survival of this population. More effective management measures are urgently needed to reverse the observed population decline.

Tissue concentrations of Fe, Zn, Cu and Mn of four Taiwanese toothed cetaceans.

Concentrations of Fe, Mn, Zn, and Cu in the muscle, lung, liver, and kidney tissues of 49 cetaceans, including 11 Kogia sima (Ks), 10 Lagenodelphis hosei (Lh), 14 Grampus griseus (Gg), and 14 Stenella attenuata (Sa) from 1994 to 2012 in Taiwan were measured. Ks exhibited the highest Fe, and the lowest Zn, Cu and Mn tissue concentrations. The Kogiid and Delphinid groups were significantly categorized by nMDS analysis. Fe muscle concentrations were found to be positively correlated with Ks, Lh, and Gg but not Sa body length. The different levels of Zn-, Cu-, and Mn- tissue concentrations of the two families were due to their different SOD systems. Their calves contained higher Cu liver concentrations. The four essential elements in cetaceans regulate homeostasis to meet their eco-physiological demand. The baseline levels for these four elements in these four tissues in the Delphinid group are defined.

Sound exposure-induced cytokine gene transcript profile changes in captive bottlenose dolphin (Tursiops truncatus) blood identified by a probe-based qRT-PCR.

Cetacean health may be potentially affected by anthropogenic sound. We have initiated investigations on the effect of low-frequency underwater sound on immunological gene transcript profiles of captive bottlenose dolphins (Tursiops truncatus) using a probe-based quantitative gene expression assay. Six immunologic genes (IL-2Rα, -4, -10, -12, TNFα and IFNγ) were selected for analysis using two validated housekeeping genes (PGK1 and HPRT1) as reference genes. Twenty-four blood samples from six clinically healthy individuals and six blood samples from individuals after sound exposures were available. The gene transcript profile of sound-exposed dolphins was consistent with a stress-induced TH2 shift profile as compared to controls. This study may lead to better understanding of the effects of anthropogenic sound on immune responses of cetaceans.

A new species of Stigmatomma from Taiwan (Hymenoptera, Formicidae, Amblyoponinae).

Stigmatomma is the most speciose ant genus in the subfamily Amblyoponinae. In the present paper, the worker caste of a new species is described, S. luyiaesp. n., which was collected from a soil sample in a subtropical evergreen broad-leaved forest in Taiwan. An identification key to the females of Stigmatomma species with 11 antennomeres occurring in Asia is also provided.

Topographic effect on the phenology of Ficus pedunculosa var. mearnsii (Mearns fig) in its northern boundary distribution, Taiwan.

Mearns fig grows at the edge of coastal vegetation on uplifted coral reefs, its population and mutualistic-pollinators are susceptible to the influence of extreme weather. To determine the phenology of Mearns fig and the effects of various weather events under small-scale topographic differences, phenology was conducted for 3 years and 7 months. Results showed that Mearns figs had multiple leaf and fig productions year-round. Topographic effects caused population in Frog Rock Trail and Jialeshuei, which are less than 10 km away from each other, to exhibit different phenological patterns after experiencing severe weather events. Northeast monsoons led the Jialeshuei population to show low amounts of leaves and figs in winter and the phenological production was also susceptible to disturbances by typhoons in summer. Fig reproduction in such environment was disadvantageous to maintain pollinators. Besides, topographic complex in microhabitat of Frog Rock Trail protected some individuals from these same events thus safeguard population's survival. The phenology of Mearns fig would respond to the weather events sensitively, which serve as references for estimating the mutualism system, and as indicators of climate change.

Diversification and spatial structuring in the mutualism between Ficus septica and its pollinating wasps in insular South East Asia.

BACKGROUND: Interspecific interactions have long been assumed to play an important role in diversification. Mutualistic interactions, such as nursery pollination mutualisms, have been proposed as good candidates for diversification through co-speciation because of their intricate nature. However, little is known about how speciation and diversification proceeds in emblematic nursery pollination systems such as figs and fig wasps. Here, we analyse diversification in connection with spatial structuring in the obligate mutualistic association between Ficus septica and its pollinating wasps throughout the Philippines and Taiwan. RESULTS: Ceratosolen wasps pollinating F. septica are structured into a set of three vicariant black coloured species, and a fourth yellow coloured species whose distribution overlaps with those of the black species. However, two black pollinator species were found to co-occur on Lanyu island. Microsatellite data on F. septica indicates the presence of three gene pools that broadly mirrors the distribution of the three black clades. Moreover, receptive fig odours, the specific message used by pollinating wasps to locate their host tree, varied among locations. CONCLUSIONS: F. septica and its black pollinator clades exhibited similar geographic structuring. This could be due originally to geographic barriers leading to isolation, local adaptation, and finally co-structuring. Nevertheless, the co-occurrence of two black pollinator species on Lanyu island suggests that the parapatric distribution of the black clades is now maintained by the inability of migrating individuals of black pollinators to establish populations outside their range. On the other hand, the distribution of the yellow clade strongly suggests an initial case of character displacement followed by subsequent range extension: in our study system, phenotypic or microevolutionary plasticity has allowed the yellow clade to colonise hosts presenting distinct odours. Hence, while variation in receptive fig odours allows specificity in the interaction, this variation does not necessarily lead to coevolutionary plant-insect diversification. Globally, our results evidence evolutionary plasticity in the fig-fig wasp mutualism. This is the first documentation of the presence of two distinct processes in pollinating fig wasp diversification on a host species: the formation of vicariant species and the co-occurrence of other species over large parts of their ranges probably made possible by character displacement.

Temperature effects on life history traits of two sympatric branchiopods from an ephemeral wetland.

Temperature effects on organisms are of multiple scientific interests, such as for their life history performance and for the study of evolutionary strategies. We have cultured two sympatric branchiopod species from an ephemeral pond in northern Taiwan, Branchinella kugenumaensis and Eulimnadia braueriana, and compared their hatching rate, maturation time, sex ratio, growth of body length, survivorship, clutch size, net reproductive rate R0, generation time TG, and intrinsic rate of natural increase r in relation to temperature (15, 20, 25 and 30°C). We found that E. braueriana had a significantly higher temperature-dependent fecundity and intrinsic population growth pattern (R0 and r). In contrast, B. kugenumaensis reproduced much slower than E. braueriana with much lower R0 (90-100 folds less) and r (about 10 folds less) at 15, 20 and 25°C and with a double as long TG at 20 and 25°C. In addition, E. braueriana increased its chance of hermaphroditic sexual reproductive mode at higher temperature because of a significantly delayed maturation of males from hermaphrodites. In contrast, B. kugenumaensis showed no significant change in reproductive mode with temperature. This is the first study indicating a significant differentiation in life history parameters of two sympatric branchiopods mediated by temperature.

Tissue concentrations of four Taiwanese toothed cetaceans indicating the silver and cadmium pollution in the western Pacific Ocean.

Muscle, lung, kidney and liver tissues of 45 bycatch and stranded cetaceans, including 14 Grampus griseus (Gg), 7 Kogia simus (Ks), 10 Lagenodelphis hosei (Lh), and 14 Stenella attenuata (Sa), were collected in the waters off Taiwan from 1994 to 1995, and from 2001 to 2012. Baseline concentrations (in µgg-1 dry weight) of the cetaceans were lung (<0.05)=muscle (<0.05)

The Trophic Significance of the Indo-Pacific Humpback Dolphin, Sousa chinensis, in Western Taiwan.

Indo-Pacific humpback dolphins (Sousa chinensis) have attracted considerable attention due to their critically endangered status and related conservation issues, but their trophic relationships and ecological significance in coastal ecosystems are poorly understood. For instance, this species is noticeably more abundant in the Xin-Huwei River Estuary (Ex) of Western Taiwan than in the nearby Zhuoshui River Estuary (Ez), though it is unclear why the distribution shows such partitioning. To explore this topic, we conducted field surveys seasonally for two years from 2012 to 2013 and constructed Ecopath models of Ex, Ez, and an offshore site (Dm) to compare energy flow within the food webs. Model comparisons showed that the availability of food resources was the main factor influencing the biomass of Indo-Pacific humpback dolphins. Specifically, its more frequent occurrence in Ex can be attributed to greater phytoplankton production and greater biomasses of macroinvertebrates and prey fish than in the other two areas. An increase in fishing activity might decrease the food availability and, consequently, the biomass of the dolphins. Although the decline in the dolphin population would increase the biomass of some prey fish species, local fishermen might not necessarily benefit from the decline due to the concurrent decrease of highly valued crabs and shrimp. Collectively, our work suggests that the Indo-Pacific humpback dolphin is a keystone species in tropical coastal waters of Taiwan, and thereby exhibit a disproportional large ecological impact given their relatively low abundance.

Selection of suitable reference genes for normalization of quantitative RT-PCR in peripheral blood samples of bottlenose dolphins (Tursiops truncatus).

Quantitative RT-PCR is often used as a research tool directed at gene transcription. Selection of optimal housekeeping genes (HKGs) as reference genes is critical to establishing sensitive and reproducible qRT-PCR-based assays. The current study was designed to identify the appropriate reference genes in blood leukocytes of bottlenose dolphins (Tursiops truncatus) for gene transcription research. Seventy-five blood samples collected from 7 bottlenose dolphins were used to analyze 15 candidate HKGs (ACTB, B2M, GAPDH, HPRT1, LDHB, PGK1, RPL4, RPL8, RPL18, RPS9, RPS18, TFRC, YWHAZ, LDHA, SDHA). HKG stability in qRT-PCR was determined using geNorm, NormFinder, BestKeeper and comparative delta Ct algorithms. Utilization of RefFinder, which combined all 4 algorithms, suggested that PGK1, HPRT1 and RPL4 were the most stable HKGs in bottlenose dolphin blood. Gene transcription perturbations in blood can serve as an indication of health status in cetaceans as it occurs prior to alterations in hematology and chemistry. This study identified HKGs that could be used in gene transcript studies, which may contribute to further mRNA relative quantification research in the peripheral blood leukocytes in captive cetaceans.

Automatic classification of delphinids based on the representative frequencies of whistles.

Classification of odontocete species remains a challenging task for passive acoustic monitoring. Classifiers that have been developed use spectral features extracted from echolocation clicks and whistle contours. Most of these contour-based classifiers require complete contours to reduce measurement errors. Therefore, overlapping contours and partially detected contours in an automatic detection algorithm may increase the bias for contour-based classifiers. In this study, classification was conducted on each recording section without extracting individual contours. The local-max detector was used to extract representative frequencies of delphinid whistles and each section was divided into multiple non-overlapping fragments. Three acoustical parameters were measured from the distribution of representative frequencies in each fragment. By using the statistical features of the acoustical parameters and the percentage of overlapping whistles, correct classification rate of 70.3% was reached for the recordings of seven species (Tursiops truncatus, Delphinus delphis, Delphinus capensis, Peponocephala electra, Grampus griseus, Stenella longirostris longirostris, and Stenella attenuata) archived in MobySound.org. In addition, correct classification rate was not dramatically reduced in various simulated noise conditions. This algorithm can be employed in acoustic observatories to classify different delphinid species and facilitate future studies on the community ecology of odontocetes.

Dynamics of soundscape in a shallow water marine environment: a study of the habitat of the Indo-Pacific humpback dolphin.

The underwater acoustic field is an important ecological element for many aquatic animals. This research examines the soundscape of a critically endangered Indo-Pacific humpback dolphin population in the shallow water environment off the west coast of Taiwan. Underwater acoustic recordings were conducted between late spring and late fall in 2012 at Yunlin (YL), which is close to a shipping lane, and Waisanding (WS), which is relatively pristine. Site-specific analyses were performed on the dynamics of the temporal and spectral acoustic characteristics for both locations. The results highlight the dynamics of the soundscape in two major octave bands: 150-300 Hz and 1.2-2.4 kHz. The acoustic energy in the former frequency band is mainly associated with passing container vessels near YL, while the latter frequency band is from sonic fish chorus at nighttime in both recording sites. In addition, large variation of low frequency acoustic energy throughout the study period was noticed at WS, where the water depths ranged between 1.5 and 4.5 m depending on tidal cycle. This phenomenon suggests that besides certain sound sources in the environment, the coastal soundscape may also be influenced by its local bathymetry and the dynamics of the physical environment.

Passive acoustic monitoring of the temporal variability of odontocete tonal sounds from a long-term marine observatory.

The developments of marine observatories and automatic sound detection algorithms have facilitated the long-term monitoring of multiple species of odontocetes. Although classification remains difficult, information on tonal sound in odontocetes (i.e., toothed whales, including dolphins and porpoises) can provide insights into the species composition and group behavior of these species. However, the approach to measure whistle contour parameters for detecting the variability of odontocete vocal behavior may be biased when the signal-to-noise ratio is low. Thus, methods for analyzing the whistle usage of an entire group are necessary. In this study, a local-max detector was used to detect burst pulses and representative frequencies of whistles within 4.5-48 kHz. Whistle contours were extracted and classified using an unsupervised method. Whistle characteristics and usage pattern were quantified based on the distribution of representative frequencies and the composition of whistle repertoires. Based on the one year recordings collected from the Marine Cable Hosted Observatory off northeastern Taiwan, odontocete burst pulses and whistles were primarily detected during the nighttime, especially after sunset. Whistle usage during the nighttime was more complex, and whistles with higher frequency were mainly detected during summer and fall. According to the multivariate analysis, the diurnal variation of whistle usage was primarily related to the change of mode frequency, diversity of representative frequency, and sequence complexity. The seasonal variation of whistle usage involved the previous three parameters, in addition to the diversity of whistle clusters. Our results indicated that the species and behavioral composition of the local odontocete community may vary among seasonal and diurnal cycles. The current monitoring platform facilitates the evaluation of whistle usage based on group behavior and provides feature vectors for species and behavioral classification in future studies.

Ficus (Moraceae) and fig wasps (Hymenoptera: Chalcidoidea) in Taiwan.

Although Ficus-associated wasp fauna have been extensively researched in Australasia, information on these fauna in Taiwan is not well accessible to scientists worldwide. In this study, we compiled records on the Ficus flora of Taiwan and its associated wasp fauna. Initial agronomic research reports on Ficus were published in Japanese in 1917, followed by reports on applied biochemistry, taxonomy, and phenology in Chinese. On the basis of the phenological knowledge of 15 species of the Ficus flora of Taiwan, recent research has examined the pollinating and nonpollinating agaonid and chalcid wasps (Hymenoptera: Chalcidoidea). Updating records according to the current nomenclature revealed that there are 30 taxa (27 species) of native or naturalized Ficus with an unusually high proportion of dioecious species (78%). Four species were observed to exhibit mutualism with more than one pollinating wasp species, and 18 of the 27 Ficus species were reported with nonpollinating wasp species. The number of nonpollinating wasp species associated with specific Ficus species ranges from zero (F. pumila) to 24 (F. microcarpa). Approximately half of the Taiwanese fig tree species have been studied with basic information on phenology and biology described in peer-reviewed journals or theses. This review provides a solid basis for future in-depth comparative studies. This summary of knowledge will encourage and facilitate continuing research on the pollination dynamics of Ficus and the associated insect fauna in Taiwan.

Sexual specialization in phenology in dioecious Ficus benguetensis and its consequences for the mutualism.

BACKGROUND: Timing of reproductive events has become central in ecological studies linking success in pollination and seed dispersion to optimizing the probability and periods of encounters with pollinators or dispersers. Obligate plant-insect interactions, especially Ficus-fig wasp mutualisms, offer striking examples of fine-tuned encounter optimization as biological cycles between mutualistic partners are deeply dependent on each other and intertwined over generations. Despite fig flowering phenology being crucial in maintaining Ficus-fig wasp mutualisms, until now, the forces of selection shaping the phenological evolution of dioecious fig trees have received little attention. By conducting a 2-year survey of a population of Ficus benguetensis in Northern Taiwan, we assessed whether environmental factors or other selective pressures shape the phenology of male and female fig trees. RESULTS: Constraints by mutualistic pollinating wasps and seed dispersers, rather than climatic factors, appeared to mainly shape fig phenology and allometry in F. benguetensis. We identified a new sexual specialization in dioecious fig trees: the position of fig production. We propose that the continuous male fig production on tree trunks can enhance the survival of pollinating fig wasps through faster localization of receptive figs while reducing the mutualistic conflict between the fig and its obligate pollinators. By contrast, in female trees, fig production is massive in summer, located on the twigs of the foliar crown and seem more related to seed dispersal and germination. CONCLUSIONS: Identifying variations in the allometry and phenology of dioecious figs provide valuable insights into how monoecious and dioecious species resolve mutualism conflicts and into the emergence of dioecy in fig trees.

Bioaccumulation of persistent organic pollutants in stranded cetaceans from Taiwan coastal waters.

This study focuses on analyzing PBDEs in the liver, muscle, and blubber tissues of stranded dolphins (Stenella attenuate) on the Taiwan coast to determine and compare the PBDE levels and distributions among tissue types. Total concentrations of 19 PBDEs (ΣPBDE) in male dolphins (9.97 to 436ng/g fat) were significantly higher than in female animals (2.73 to 89.5ng/g fat), implying gender variation in bioaccumulation and the possibility of generation transfer from mother to fetus during pregnancy. The levels of contamination varied among tissue type; contamination was higher in blubber than that in muscle or liver, suggesting a possible transformation and redistribution of these compounds in body burden. Aside from gender and tissue type, ΣPBDE concentrations also significantly correlated with body length, an indicator of dolphin age. PCA analysis results showed no significant difference in PBDE congener pattern distributions in blubber tissues, indicating that blubber may be the final storage of contaminants in cetaceans, and that bioaccumulation of PBDEs may be dependent on chemical properties. BDE-154 and BDE-47 were the predominant PBDE congeners in stranded dolphins, and their correlation with body length suggests the significant metabolic depletion of BDE-154 in this species and possible exposure to both penta-BDE and octa-BDE mixtures.

An automatic detection algorithm for extracting the representative frequency of cetacean tonal sounds.

Most studies on tonal sounds extract contour parameters from fundamental frequencies. The presence of harmonics and the frequency distribution of multiple tonal sounds have not been well researched. To investigate the occurrence and frequency modulation of cetacean tonal sounds, the procedure of detecting the instantaneous frequency bandwidth of tonal spectral peaks was integrated within the local-max detector to extract adopted frequencies. The adopted frequencies, considered the representative frequencies of tonal sounds, are used to find the presence of harmonics and overlapping tonal sounds. The utility and detection performance are demonstrated on acoustic recordings of five species from two databases. The recordings of humpback dolphins showed a 75% detection rate with a 5% false detection rate, and recordings from the MobySound archive showed an 85% detection rate with a 5% false detection rate. These detections were achieved in signal-to-noise ratios of -12 to 21 dB. The parameters that measured the distribution of adopted frequency, as well as the prominence of harmonics and overlaps, indicate that the modulation of tonal sounds varied among different species and behaviors. This algorithm can be applied to studies on cetacean communication signals and long-term passive acoustic monitoring.

Phenology and pollinating wasp dynamics of Ficus microcarpa L.f.: adaptation to seasonality.

BACKGROUND: In the obligate plant/pollinator mutualism, pollinator abundance is conditioned by the host resource. In order to investigate the population fluctuation of pollinating wasps and the phenological processes involved, this study examined the dual dynamics of the pollinator and the syconium phenology of a seasonal fruited fig tree population, Ficus microparpa, in Taipei, Taiwan. RESULTS: Our results revealed three seasons in the annual phenology: spring crop, summer-fall crop and winter trough seasons. The syconium quantity was correlated most significantly with temperature based on the generalized linear model with the meteorological data transformed by a principal component analysis. The pollinator population showed an increasing trend in spring, reached the maximum abundance in summer, and then declined drastically in winter, consistent with the syconium production fluctuation. With the small amount of local pollinators from the winter syconia and potential immigrating foundresses from other populations, the pollinator population size can increase very quickly from almost zero to over 40,000 wasps for this 29-tree local population within a season. CONCLUSION: This syconium phenological scheme, coupled with the fast-recovery rate of pollinators, may explain the worldwide adaptation and invasion of Ficus microcarpa.

An extreme case of plant-insect codiversification: figs and fig-pollinating wasps.

It is thought that speciation in phytophagous insects is often due to colonization of novel host plants, because radiations of plant and insect lineages are typically asynchronous. Recent phylogenetic comparisons have supported this model of diversification for both insect herbivores and specialized pollinators. An exceptional case where contemporaneous plant-insect diversification might be expected is the obligate mutualism between fig trees (Ficus species, Moraceae) and their pollinating wasps (Agaonidae, Hymenoptera). The ubiquity and ecological significance of this mutualism in tropical and subtropical ecosystems has long intrigued biologists, but the systematic challenge posed by >750 interacting species pairs has hindered progress toward understanding its evolutionary history. In particular, taxon sampling and analytical tools have been insufficient for large-scale cophylogenetic analyses. Here, we sampled nearly 200 interacting pairs of fig and wasp species from across the globe. Two supermatrices were assembled: on an average, wasps had sequences from 77% of 6 genes (5.6 kb), figs had sequences from 60% of 5 genes (5.5 kb), and overall 850 new DNA sequences were generated for this study. We also developed a new analytical tool, Jane 2, for event-based phylogenetic reconciliation analysis of very large data sets. Separate Bayesian phylogenetic analyses for figs and fig wasps under relaxed molecular clock assumptions indicate Cretaceous diversification of crown groups and contemporaneous divergence for nearly half of all fig and pollinator lineages. Event-based cophylogenetic analyses further support the codiversification hypothesis. Biogeographic analyses indicate that the present-day distribution of fig and pollinator lineages is consistent with a Eurasian origin and subsequent dispersal, rather than with Gondwanan vicariance. Overall, our findings indicate that the fig-pollinator mutualism represents an extreme case among plant-insect interactions of coordinated dispersal and long-term codiversification. [Biogeography; coevolution; cospeciation; host switching; long-branch attraction; phylogeny.].