Behavioural changes and potential consequences of cetacean exposure to purse seine vessels in the Istanbul Strait, Turkey

2020 ◽  
Vol 100 (5) ◽  
pp. 847-856
Author(s):  
Cristóbal Olaya Meza ◽  
Aylin Akkaya ◽  
Flavio Affinito ◽  
Bayram Öztürk ◽  
Ayaka Amaha Öztürk
Keyword(s):  
Bottlenose Dolphins ◽  
Purse Seine ◽  
Traffic Density ◽  
Long Term Effects ◽  
Cetacean Species ◽  
Behavioural Changes ◽  
Fishing Vessels ◽  
Marine Traffic ◽  
Common Dolphins

AbstractMarine traffic has both short- and long-term effects on cetacean behaviour, yet fishing vessels present a unique situation as they disturb cetaceans whilst potentially offering alternative foraging opportunities. The Istanbul Strait is a key area for the study of anthropogenic disturbance on cetaceans due to heavy human pressure in a narrow space where at least three cetacean species are regularly encountered. The present study investigated changes in behaviour of bottlenose dolphins, common dolphins and harbour porpoises in relation to the presence of purse seiners using Markov chains analysis. The results revealed increased foraging in bottlenose and common dolphins' behavioural budgets and a decrease in the time spent foraging by harbour porpoises. Moreover, a loglinear model was used to analyse the effect of possible confounding variables on observed behaviours. The only variables found to be affecting behaviour were the previous recorded behaviour, seiner presence and marine traffic density. Consequently, the presence of purse seine vessels leads bottlenose and common dolphins to change their behaviour and are related with a decrease of energy intake in porpoises. The results of this study reveal that there is an effect of purse seine vessel presence on the cetaceans found in the Istanbul Strait with potentially significant impacts on their behaviour, therefore we suggest more research is needed in the area to identify the long-term impacts of these observed behavioural changes.

scholarly journals Determinants of lungworm specificity in five cetacean species in the western Mediterranean

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Rachel Pool ◽  
Clara Romero-Rubira ◽  
Juan Antonio Raga ◽  
Mercedes Fernández ◽  
Francisco Javier Aznar
Keyword(s):  
Bottlenose Dolphins ◽  
Parasite Burden ◽  
Western Mediterranean ◽  
Host Size ◽  
Cetacean Species ◽  
Stenella Coeruleoalba ◽  
Species Similarity ◽  
Pilot Whales ◽  
Common Dolphins ◽  
Prey Overlap

Abstract Background Current data about Pseudaliidae show contrasting patterns of host specificity between congeneric species. We investigated how both contact and compatibility between hosts and parasites contributed to the patterns of lungworm infection observed in a community of five species of cetaceans in the western Mediterranean. Methods The lungs of 119 striped dolphins Stenella coeruleoalba, 18 bottlenose dolphins Tursiops truncatus, 7 Risso’s dolphins Grampus griseus, 7 long-finned pilot whales Globicephala melas, and 6 common dolphins Delphinus delphis were analysed for lungworms. Parasites were identified by morphology and analysis of ITS2 sequences using both maximum likelihood and Bayesian inference methods. Body length was used as a proxy for lungworm species fitness in different hosts and compared with Kruskal-Wallis tests. Infection parameters were compared between cetacean species using Fisher’s exact tests and Kruskal-Wallis tests. Phylogenetic specificity was explored by collating the overall lungworm species prevalence values in hosts from previous surveys in various localities. To explore the relative importance of vertical and horizontal transmission, Spearman’s rank correlation was used to look for an association between host size and lungworm burden. A Mantel test was used to explore the association between lungworm species similarity and prey overlap using dietary data. Results Halocercus delphini had higher infection levels in striped dolphins and common dolphins; Stenurus ovatus had higher infection levels in bottlenose dolphins; and Stenurus globicephalae had higher infection levels in long-finned pilot whales. These results are congruent with findings on a global scale. Morphometric comparison showed that the larger nematodes were found in the same host species that had the highest parasite burden. Lungworms were found in neonatal striped dolphins and a Risso’s dolphin, and there was a weak but significant correlation between host size and parasite burden in striped dolphins and bottlenose dolphins. There was also a weak but significant association between prey overlap and lungworm species similarity. Conclusions Data indicate that phylogenetic specificity has an important role in governing host–parasite associations, as indicated by the higher infection levels and larger nematode size in certain hosts. However, diet can also influence infection patterns in these preferred hosts and contribute to less severe infections in other hosts.

scholarly journals Cetacean habitat modelling to inform conservation management, marine spatial planning, and as a basis for anthropogenic threat mitigation in Indonesia

2020 ◽  
Author(s):  
Achmad Sahri ◽  
Mochamad Iqbal Herwata Putra ◽  
Putu Liza Kusuma Mustika ◽  
Danielle Kreb ◽  
Albertinka J. Murk
Keyword(s):  
Spatial Planning ◽  
Oil And Gas ◽  
Traffic Density ◽  
Individual Species ◽  
Marine Spatial Planning ◽  
Suitable Habitat ◽  
Cetacean Species ◽  
Management Planning ◽  
Marine Traffic ◽  
Conservation And Management

ABSTRACTIndonesia harbours a high diversity of cetaceans, yet effective conservation is hampered by a lack of knowledge about cetacean spatial distribution and habitat preferences. This study aims to address this knowledge gap at an adequate resolution to support national cetacean conservation and management planning. Maximum Entropy (Maxent) modelling was used to map the distribution of 15 selected cetacean species in seven areas within Indonesian waters using recent cetacean presence datasets as well as environmental predictors (topographic and oceanographic variables). We then combined the individual species suitable habitat maps and overlaid them with provincial marine spatial planning (MSP) jurisdictions, marine protected areas (MPAs), oil and gas contract areas, and marine traffic density. Our results reflect a great heterogeneity in distribution among species and within species among different locations. This heterogeneity reflects an interrelated influence of topographic variables and oceanographic processes on the distribution of cetacean species. Bathymetry, distance to-coast and −200m isobaths, and Chl and SST were important variables influencing distribution of most species in many regions. Areas rich in species were mainly related to high coastal or insular-reef complexity, representing high productivity and upwelling-modified waters. Although some important suitable habitats currently fall within MPAs, other areas are not and overlap with oil and gas exploration activities and marine traffic, indicating potentially high risk areas for cetaceans. The results of this study can support national cetacean conservation and management planning, and be used to reduce or avoid adverse anthropogenic threats. We advise considering currently unprotected suitable cetacean habitats in MPA and MSP development.

scholarly journals Cetacean mortality due to interactions with fisheries and marine litter ingestion in the Croatian part of the Adriatic Sea from 1990 to 2019

2021 ◽  
Vol 91 (2) ◽  
pp. 189-206
Author(s):  
Martina Đuras ◽  
◽  
Ana Galov ◽  
Kim Korpes ◽  
Magdalena Kolenc ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Bottlenose Dolphins ◽  
Surveillance Program ◽  
Cetacean Species ◽  
Term Survival ◽  
Stenella Coeruleoalba ◽  
Marine Litter ◽  
Surveillance Programs ◽  
Fisheries Interactions

Various anthropogenic threats negatively influence the survival of cetaceans in all world seas. Thanks to a long-running marine mammal surveillance program, we are able to report the results of a detailed analysis of the influence of cetacean-fisheries interactions and marine litter ingestion on cetacean mortality in the Croatian part of the Adriatic Sea over the last three decades. The total number of dead cetaceans was 459, and included 334 bottlenose dolphins (Tursiops truncatus), 40 striped dolphins (Stenella coeruleoalba), ten Risso’s dolphins (Grampus griseus), six Cuvier’s beaked whales (Ziphius cavirostris) and four fin whales (Balaenoptera physalus). Three hundred of them were examined postmortally. Cetacean-fisheries interaction occurred frequently in the Adriatic Sea, being detected in 96 (20.9%) of the recorded cases. Bycatch was the most abundant cetacean-fisheries interaction, with 66 (14.4%) cases recorded. Good nutritional condition and evidence of recent feeding were the most common findings recorded in bycatch cases, followed by persistent froth in the airways, edematous lungs, bruises and an amputated fluke or tail. Cetacean-fisheries interactions other than bycatch affected 30 animals and included larynx strangulations, long-term tail entanglement and fishing gear in the stomach. Ingestion of marine litter that was not related to fisheries was recorded in four animals. This study reveals the considerable negative anthropogenic influence on cetaceans in the Adriatic Sea, especially the bottlenose dolphin that is considered to be the most numerous cetacean species therein, and demonstrates the need for the urgent development of a cetacean bycatch reduction program. Finally, it also shows the importance of sustaining national surveillance programs to gain scientifically based knowledge important for cetacean protection and prospects for their long-term survival.

scholarly journals Cetacean–fishery interactions in Galicia (NW Spain): results and management implications of a face-to-face interview survey of local fishers

2013 ◽  
Vol 71 (3) ◽  
pp. 604-617 ◽  
Author(s):  
Sabine Goetz ◽  
Fiona L. Read ◽  
M. Begoña Santos ◽  
C. Pita ◽  
Graham J. Pierce
Keyword(s):  
Bottlenose Dolphins ◽  
Management Strategies ◽  
Economic Loss ◽  
Fishing Effort ◽  
Purse Seine ◽  
Fishing Gear ◽  
Nw Spain ◽  
Face To Face ◽  
Fishery Interactions ◽  
Common Dolphins

Abstract Galicia (NW Spain) is an important fishing region with a high potential for cetacean–fishery interactions. Cetacean depredation on catch and damage to fishing gear can potentially lead to substantial economic loss for fishers, while cetacean bycatch raises conservation concerns. With the aim of gathering information on the types and scale of interactions and of suggesting possible management strategies, we conducted face-to-face interviews with fishers in local fishing harbours, in particular to identify specific problematic interactions and to quantify the level of economic loss and bycatch rates associated with these interactions. We found that cetacean–fishery interactions are frequent, although damage to catch and fishing gear by cetaceans was mostly reported as small. Nevertheless, substantial economic loss can result from common bottlenose dolphins (Tursiops truncatus) damaging coastal gillnets and from short-beaked common dolphins (Delphinus delphis) scattering fish in purse-seine fisheries. Cetacean bycatch mortality was reported to be highest for trawls and set gillnets, and probably exceeds sustainable levels for local common and bottlenose dolphin populations. Although interview data may be biased due to the perceptions of interviewees, and therefore should be interpreted with care, the methodology allowed us to cover multiple sites and fisheries within a reasonable time frame. Minimizing cetacean–fishery interactions requires the implementation of case-specific management strategies with the active participation of fishers. For set gillnet and purse-seine fisheries, the use of acoustic deterrent devices (pingers) may prevent cetaceans from approaching and getting trapped in the nets. For trawl fisheries, where bycatch appears to be particularly high at night in water depths of 100–300 m, possible solutions include the implementation of time/area closures and the relocation of some fishing effort to deeper waters.

scholarly journals Habitat preferences among three top predators inhabiting a degraded ecosystem, the Black Sea

2017 ◽  
Vol 81 (2) ◽  
pp. 217 ◽  
Author(s):  
Alicia Sánchez-Cabanes ◽  
Maja Nimak-Wood ◽  
Nicola Harris ◽  
Renaud De Stephanis
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Black Sea ◽  
Bottlenose Dolphins ◽  
Habitat Preferences ◽  
Additive Models ◽  
Sea Surface ◽  
The Black Sea ◽  
Cetacean Species ◽  
Common Dolphins

This study investigated whether there is evidence of widespread niche partitioning based on environmental factors in the Black Sea and tested the hypothesis that physiographic factors may be employed as predictors. It addresses poorly researched areas with good habitat potential for the only three cetacean subspecies living in this area: the Black Sea short-beaked common dolphin (Delphinus delphis spp. ponticus), the Black Sea bottlenose dolphin (Tursiops truncatus spp. ponticus) and the Black Sea harbour porpoise (Phocoena phocoena spp. relicta). Generalized additive models (GAMs) were used to analyse data collected from multiple sources. In total, 745 sightings of the three species between 1998 and 2010 throughout the Black Sea were included. The analysis found depth and sea surface temperature to be the most important variables for separating the occurrence of the three species. Common dolphins occurred mainly in deep waters and in areas where the sea surface temperature was low, bottlenose dolphins were distributed primarily in shallower and warmer waters than common dolphins, and harbour porpoises were distributed in shallower waters with lower sea surface temperature than bottlenose dolphins. This study suggests strong niche segregation among the three cetacean species. The study is also the first contribution to the basic information of cetacean species distribution and habitat preferences in the Black Sea as a whole. Knowledge of the distribution of the three dolphin species in the study area is essential to establish conservation measures for these populations.

scholarly journals How to Work on a Non-endangered Species and Contribute to Cetacean Conservation: An Example by the Sarasota Dolphin Research Program

2021 ◽  
Vol 8 ◽  
Author(s):  
Frances M. D. Gulland
Keyword(s):  
Endangered Species ◽  
Research Program ◽  
Bottlenose Dolphins ◽  
Cetacean Species ◽  
Sarasota Bay ◽  
Conservation Actions ◽  
Data Deficient ◽  
Iucn Red Data List ◽  
Term Data

The world’s most endangered small cetaceans are found in countries many miles from Sarasota Bay and its common bottlenose dolphins (Tursiops truncatus). Information on the ecology and threats to many of these endangered cetaceans is often far more limited than that on bottlenose dolphins, with the IUCN Red Data List describing many species as “data deficient.” In many developing nations where these rare species occur, resources for research and monitoring are scant, and logistical challenges further limit research into marine mammal health and population status and their threats. The Sarasota Dolphin Research Program (SDRP) has tackled this problem by using the bottlenose dolphin as a model for cetacean species in other parts of the world and using its resources to assist scientists working with more endangered species of cetacean. The celebration of 50 years of study by the SDRP exemplifies how using long-term data on known individuals can advance the fields of cetacean behavior, ecology, life history, physiology, toxicology, and medicine, all providing information for informing certain conservation actions. The Sarasota team has used their work to inform conservation policy both home and abroad.

scholarly journals Air Pollution and Mortality: Timing Is Everything

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1274
Author(s):  
Frederick W. Lipfert
Keyword(s):  
Air Pollution ◽  
Time Series ◽  
Air Quality ◽  
Indoor Air Pollution ◽  
Health Effect ◽  
Traffic Density ◽  
Long Term Effects ◽  
Short Term ◽  
Long Term Studies

This paper considers timing issues in health-effect exposure and response studies. Short-term studies must consider delayed and cumulative responses; prior exposures, disease latency, and cumulative impacts are required for long-term studies. Lacking individual data, long-term air quality describes locations, as do greenspaces and traffic density, rather than exposures of residents. Indoor air pollution can bias long-term exposures and effect estimates but short-term effects also respond to infiltrated outdoor air. Daily air quality fluctuations may affect the frail elderly and are necessarily included in long-term averages; any true long-term effects must be given by differences between annual and daily effects. I found such differences to be negligible after adjusting for insufficient lag effects in time-series studies and neglect of prior exposures in long-term studies. Aging of subjects under study implies cumulative exposures, but based on age-specific mortality, I found relative risks decreasing with age, precluding cumulative effects. A new type of time-series study found daily mortality of previously frail subjects to be associated with various pollutants without exposure thresholds, but the role of air pollution in the onset of frailty remains an unexplored issue. The importance of short-term fluctuations has been underestimated and putative effects of long-term exposures have been overestimated.

Host specificity ofOschmarinella rochebruniandBrachycladium atlanticum(Digenea: Brachycladiidae) in five cetacean species from western Mediterranean waters

2010 ◽  
Vol 85 (1) ◽  
pp. 12-19 ◽  
Author(s):  
P. Mateu ◽  
J.A. Raga ◽  
F.J. Aznar
Keyword(s):  
Host Species ◽  
Bottlenose Dolphins ◽  
Western Mediterranean ◽  
Its2 Region ◽  
Single Individual ◽  
Common Dolphin ◽  
Cetacean Species ◽  
Stenella Coeruleoalba ◽  
Pilot Whales ◽  
Common Dolphins

AbstractWe investigated patterns of specificity of liver flukes (fam. Brachycladiidae) in a community of cetaceans from the western Mediterranean. The liver and pancreas of 103 striped dolphins,Stenella coeruleoalba, 18 Risso's dolphins,Grampus griseus, 14 bottlenose dolphins,Tursiops truncatus, 8 common dolphins,Delphinus delphis, and 5 long-finned pilot whales,Globicephala melas, were analysed for brachycladiid species. Two species were found:Oschmarinella rochebruniin striped dolphins (prevalence (P): 61.2%; mean intensity (MI) (95% CI): 34.2 (25.7–45.6)), andBrachycladium atlanticumin striped dolphins (P: 39.8%; MI: 7.1 (4.8–13.1)) and a single individual of common dolphin (P: 12.5%; intensity: 19), which represents a new host record. A molecular analysis using the internal transcribed spacer 2 (ITS2) region of the rDNA gene confirmed that specimens ofB. atlanticumwere conspecific regardless of host species. Available dietary data suggest that Risso's dolphins, bottlenose dolphins and long-finned pilot whales would contact rarely, if at all, the infective stages ofO. rochebruniandB. atlanticum. Neither the prevalence nor the mean abundance ofB. atlanticumdiffered significantly between striped and common dolphins, but a principal component analysis using seven morphometric variables indicated that specimens collected from the common dolphin were stunted. These worms also had fewer eggs compared with specimens typically found in striped dolphins, although the size of the eggs was similar in both host species. Dwarfism and low fecundity have typically been found in helminths infecting unusual host species, and might reflect the lower compatibility ofB. atlanticumfor common dolphins. In summary, bothO. rochebruniandB. atlanticumappear to exhibit a narrow specificity for striped dolphins in the western Mediterranean.

Immediate response of Atlantic bottlenose dolphins to high-speed personal watercraft in the Mississippi Sound

2008 ◽  
Vol 88 (6) ◽  
pp. 1139-1143 ◽  
Author(s):  
Lance J. Miller ◽  
Moby Solangi ◽  
Stan A. Kuczaj
Keyword(s):  
Marine Mammals ◽  
High Speed ◽  
Bottlenose Dolphins ◽  
Well Being ◽  
Anthropogenic Factors ◽  
Long Term Effects ◽  
Mississippi Sound ◽  
Personal Watercraft ◽  
The Impact

Measuring the impact of anthropogenic factors on marine mammals is critical to the conservation of these species. Recently, the effect of personal watercraft on marine mammal behaviour and well-being has become a topic of increasing concern. The purpose of this study was to examine the immediate effects of high-speed personal watercraft on Atlantic bottlenose dolphin (Tursiops truncatus) behaviour. Opportunistic surveys were conducted from a research vessel in the Mississippi Sound (30º13′22.6″N 89º01′36.5″W) from September 2003 through to August 2005. The passing of a high-speed personal watercraft significantly increased dolphin dive duration, dolphin group cohesion and dolphin breathing synchrony. Additionally, in 47% of the encounters a dolphin group's behaviour changed within one minute of the presence of a high-speed personal watercraft. The most notable changes were an increase in dolphin travelling behaviour and a decrease in feeding behaviour following the boat's presence. The results demonstrated an immediate, short-term change in dolphin behaviour, suggesting that an increase in the frequency of high-speed personal watercraft in this area could produce long-term detrimental effects. Research on the long-term effects of boat traffic on marine mammals is clearly needed to assess and hopefully mediate any potential long-term effects.

scholarly journals Long-Term Demographic and Spatio-Temporal Trends of Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) Bycatch in Bather Protection Nets off KwaZulu-Natal, South Africa

2020 ◽  
Vol 7 ◽  
Author(s):  
Stephanie Plön ◽  
Christine Erbe ◽  
Sabine Wintner
Keyword(s):  
South Africa ◽  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Temporal Trends ◽  
Long Term Effects ◽  
Annual Fluctuation ◽  
Tursiops Aduncus ◽  
Kwazulu Natal ◽  
The Impact

Bather protection nets have been in place off the coast of KwaZulu-Natal (KZN), South Africa, since the 1950’s. Besides sharks, they also catch a number of other marine vertebrates, including dolphins, the majority of which are Indo-Pacific bottlenose dolphins Tursiops aduncus. Previous analyses of dolphin bycatch in the nets indicated the potential impacts on the local populations, but a lack of information on population structure has to-date hindered a more detailed assessment. A recent re-assessment of the status and population delineations of T. aduncus off South Africa prompted a re-examination of demographic, spatial, and temporal patterns of its catches in bather protection nets over a 36-year period (January 1980 to December 2015). In total, 1169 dolphins were caught, including a slightly greater number of females and juveniles than other sex-classes, raising concern about the potential long-term effects on population demographics. More dolphins were caught off the North than the South coast. Temporal trends indicate that the bycatch during June and July every year (peak Sardine Run period) as a percentage of overall dolphin bycatch has been steadily decreasing from 39.8% in 1980 to 13% in 2015. A large inter-annual fluctuation can be seen, probably as a result of the inter-annual intensity of the Sardine Run. Although our results do not indicate a long-term decline of the individual populations as previously predicted, revised abundance estimates and data on the demographics and movement patterns of the animals are urgently required to accurately assess the impact of bycatch on the Indo-Pacific bottlenose dolphin populations off KZN and to advise conservation and management decisions going forward.

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