Mass mortality event of Black Sea Harbour Porpoises

The subspecies Phocoena phocoena relicta is endemic to the Black Sea and whilst the total population size and trend are unknown, the subspecies is red-listed as Endangered. In recent months, unusually large numbers of neonates and juveniles have washed up on beaches along the Black Sea coasts of Bulgaria and Turkey. The waters there are known to be used by cetaceans for calving and breeding (Dede & Tonay, 2010). Large-scale mortality events have been reported in previous years, but the number of individuals this year has been exceptionally high, with up to 7.2ind./km stranded on the Turkish western Black Sea coast (more than 150 individuals found along a 22km stretch of coastline in July alone). Most were newborn (91%) harbour porpoises (97%), often less than 70cm long. It has been difficult to diagnose cause of death because most of the carcasses were in an advanced stage of decomposition by the time they washed up and were found. The situation in Bulgaria has been similar, with a peak of stranded porpoises, 61-77 cm long, in mid-July, and 6.6ind./km stranded on the Black Sea coast of southern Bulgaria (34 individuals in 3 days along 5.1 km of beach).

Unusual large-scale mortality events were observed in 2003 and 2009 (Tonay et al., 2012) and high mortality of neonates in the summers of 2010 and 2011 was thought to be related to the bottom-set gillnet fishery for turbot (Öztürk et al., 2012). The hypothesis was that lactating and nursing mothers had been caught in nets, resulting in the neonates starving to death and washing ashore. However, whilst this year the strandings seem to be dominated once again by neonates, the number of observed carcasses is much higher than was the case in previous mass mortality events.

Scientists at the University of Istanbul and the Turkish Marine Research Foundation (TUDAV) as well as Dimitar Popov of Green Balkans from Bulgaria, are investigating this year’s mortality event and the causes behind it. For a subspecies that is already considered Endangered, the high mortality of young animals, year after year, could be a serious impediment to recovery.

tudav mass2tudav mass1

tudav_mass4tudav mass3Figure 1. Stranded harbour porpoise neonates in the Black Sea. © TUDAV.

 

References:

Dede, A., Tonay, A. 2010. Cetacean sightings in the western Black Sea in autumn 2007. Journal of Environmental Protection and Ecology 11(4): 1491-1494.

Öztürk, A.A., Tonay, A.M, Raykov, V., Dede, A. 2012. High mortality of harbour porpoise neonates in the southwestern Black Sea in 2010 and 2011. Abstract in proceedings of 26th Annual Conference of the European Cetacean Society, Galway, 90p.

Tonay, A.M., Dede, A., Öztürk, A.A., Ercan, D., Fernández, A. 2012. Unusual mass mortality of cetaceans on the coast of the Turkish Western Black Sea in summer 2009. Journal of the Black Sea/ Mediterranean Environment 18: 65-75.

 

 

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Collaboration on humpback dolphin (Sousa plumbea) research and conservation in South and East Africa

Humpback dolphins in the Indian Ocean were recently recognised as a distinct species (Sousa plumbea) that occurs in coastal waters from South Africa to India (link to earlier news article).  The species occurs in very near-shore habitat, generally in water less than 30 m deep and typically less than 2 km from shore, and is therefore exposed to high levels of human activity throughout its range. The conservation status of all four Sousa species is currently being assessed for the Red List, and S. plumbea has been proposed (but has not yet been listed) as “Endangered”.

Humpback dolphins are considered to be South Africa’s most endangered marine mammals.  They were recently re-assessed for the South African National Red List, and the status was changed from Vulnerable to Endangered due to declining sighting rates and group sizes, in comparison to previous assessments, as well as newly available estimates of abundance from discrete areas that suggest the overall population size in South Africa is very small [1].

In early 2016, a Memorandum of Understanding (MOU) that established the “SouSA Consortium” was signed by 16 scientists and research groups in South Africa.

Figure 1: Some of the signatories of the SouSA Consortium Memorandum of Understanding in South Africa

Figure 1: Some of the signatories of the SouSA Consortium Memorandum of Understanding in South Africa

The consortium is designed to facilitate the collection and sharing of humpback dolphin data across the country, which is hoped to make a substantial contribution towards the conservation of this species.   Specifically, the consortium aims to generate data and analyses on a larger geographical scale, something that is impossible for individual research groups. The specific objectives of the project are to:

  • produce an estimate of the total population size and trend of humpback dolphins in South African waters
  • characterize the movement patterns of humpback dolphins along the entire South African coastline
  • determine spatial and temporal patterns of humpback dolphin distribution and assess connectivity between areas
  • evaluate population viability (incorporating estimates of abundance, reproduction and survival) of humpback dolphins in South Africa.

In Kenya and Tanzania (East Africa), knowledge of humpback dolphins is less extensive than in South Africa, but populations appear to be similarly small and subject to many threats [2]. Funding is secured and plans are in place to sign a MOU to establish an East African Cetacean Working Group that will collaborate on coastal dolphin research and conservation in Kenya and Tanzania.  The East African working group will have similar objectives to the South African SouSA Consortium, and the two groups intend to work together in future to answer broad-scale regional questions related to humpback dolphin conservation.

These types of collaborations are important and to be encouraged in areas where knowledge and resources are limited, but conservation concerns are high, something that is true for many regions and marine mammal species. Fisheries bycatch and the loss of habitat through coastal development are major conservation concerns for coastal small cetaceans that can rarely be addressed adequately by projects working in isolation. Recent reviews of the status of all four species in the genus Sousa (S. teuszii [3]; S. plumbea [2]; S. chinensis [4] and S. sahulensis [5] provide evidence for significant declines in most areas, and much more work is needed to increase scientific knowledge and raise public awareness.

 

References

  1. Plön, S., V.G. Cockcroft, and W.P. Froneman. 2015 Chapter Six – The Natural History and Conservation of Indian Ocean Humpback Dolphins (Sousa plumbea) in South African Waters, in Advances in Marine Biology, T.A. Jefferson and B.E. Curry, Editors, Academic Press. p. 143-162.
  2. Braulik, G.T., K. Findlay, S. Cerchio, and R. Baldwin. 2015 Chapter Five – Assessment of the Conservation Status of the Indian Ocean Humpback Dolphin (Sousa plumbea) Using the IUCN Red List Criteria, in Advances in Marine Biology, T.A. Jefferson and B.E. Curry, Editors, Academic Press. p. 119-141.
  3. Collins, T. 2015 Chapter Three – Re-assessment of the Conservation Status of the Atlantic Humpback Dolphin, Sousa teuszii (Kükenthal, 1892), Using the IUCN Red List Criteria, in Advances in Marine Biology, T.A. Jefferson and B.E. Curry, Editors, Academic Press. p. 47-77.
  4. Jefferson, T.A. and B.D. Smith. 2016 Chapter One – Re-assessment of the Conservation Status of the Indo-Pacific Humpback Dolphin (Sousa chinensis) Using the IUCN Red List Criteria, in Advances in Marine Biology, T.A. Jefferson and B.E. Curry, Editors, Academic Press. p. 1-26.
  5. Parra, G.J. and D. Cagnazzi. 2016 Chapter Seven – Conservation Status of the Australian Humpback Dolphin (Sousa sahulensis) Using the IUCN Red List Criteria, in Advances in Marine Biology, T.A. Jefferson and B.E. Curry, Editors, Academic Press. p. 157-192.

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A tribute to the late Natalie Goodall and her museum at the end of the world

Peter Thomas at the Marine Mammal Commission kindly forwarded the following link, which we thought would be of interest to CSG members https://www.hakaimagazine.com/article-long/museum-end-world. Natalie was long active in the CSG, and many of you knew her and visited the unique collection of marine mammal material that she amassed in what was, by any measure, a remarkable life.

 

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New SSC Panel: Advising on Dolphin Research and Conservation in China’s Pearl River Estuary

A Steering Committee chaired by Randall Reeves, with Bob Brownell, Rohan Currey, Frances Gulland, Randall Wells and Wang Ding as the other members, was recently established to assist Ocean Park Conservation Foundation Hong Kong (OPCFHK) in a long-term effort to support management measures and conservation-related research for Indo-Pacific humpback dolphins (Sousa chinensis), locally known as Chinese white dolphins (CWDs), in the Pearl River Estuary (PRE) and around Hong Kong. The first year of this initiative, which is founded on close collaboration among the CSG, the IUCN SSC Conservation Breeding Specialist Group (CBSG) and the Wildlife Health Specialist Group, has been funded through a grant to OPCFHK from the Hong Kong Airport Authority. To ensure transparency, relevant documentation (e.g. terms of reference, meeting agendas, reports) and updated information on activities within the program will be provided via a dedicated Special Projects page of the CSG website.

As a first step towards developing an overarching conservation framework and action plan, OPCFHK organized a Population Viability Analysis (PVA) workshop, led by Phil Miller of the CBSG, in Hong Kong from 30 March to 1 April 2016. In addition to the Steering Committee, the workshop was attended by Chinese and international scientists who have been studying the PRE CWD population, some of them for several decades – CSG members Bernd Würsig and Lindsay Porter, along with Samuel Hung, John Wang, and Leszek Karczmarski. CSG member Tom Jefferson, another PRE CWD expert, participated remotely for short periods. A workshop report that includes model specifications and initial results of the PVA is expected in September or October 2016. This will provide the basis for a CBSG-led conservation planning workshop with stakeholders, again in Hong Kong, in early 2017.

The Indo-Pacific humpback dolphin is currently red-listed as Near Threatened. The only subpopulation that has been formally assessed is in eastern Taiwan Strait (recently recognized as a subspecies, S. chinensis taiwanensis), listed as Critically Endangered. Both S. chinensis and the PRE subpopulation, along with the other three species currently recognized in the genus Sousa (S. sahulensis, S. plumbea and S. teuszii), were assessed at a CSG Red List workshop in May 2015. It is expected that the new assessments of all four Sousa species will be finalized before the end of this year but a formal Red List assessment of the PRE subpopulation is pending until the western extent of its range can be more clearly delineated. Meantime, however, it is clear that the PRE dolphins are in decline, living as they do in an environment that is being rapidly and massively degraded by myriad threats – intense vessel traffic (including high-speed ferries); commercial and recreational fishing; dredging and dumping to facilitate navigation and large-scale land ‘reclamation’; bridge and pier construction; and pollution from household, industrial and agricultural sources.

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Five Irrawaddy dolphins rescued by local stranding network

Petch Manopawitr, Deputy Head of IUCN Southeast Asia Group and Director of the IUCN Thailand/Cambodia Transborder Coastal Dolphin Project shared a video link of five Irrawaddy dolphins that became stranded on 5 May 2016 behind a bamboo fence built to prevent erosion at Krasakao Village in the upper Gulf of Thailand near Bangkok.  Volunteers from a local dolphin stranding network and staff from the Department of Marine and Coastal Resources spent a hot afternoon rescuing and successfully releasing the dolphins back to sea. Petch said that the video shows the success of training provided by IUCN to the dolphin stranding network and the positive local support they have generated for dolphin conservation. The dedication of these local people for saving these dolphins under extremely difficult conditions in the deep mud is inspiring and it bodes well for the long-term  success of conservation efforts for Irrawaddy dolphins in the Gulf of Thailand.

The video can be accessed here.

 


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IUCN Letter to the Indian Minister of Environment – Concern over the impact of India’s National Waterways Act on Ganges River dolphins

In early April attention was drawn to India’s National Waterways Act 2016, which calls for massive reconfiguration of the Ganges and Brahmaputra river systems into inland waterways to facilitate transport cargo, coal, and industrial raw materials and to support tourism development. Given the serious implications for Ganges river dolphins and other riverine fauna, CSG members with long experience working on river dolphin science and conservation in the subcontinent prompted IUCN to send a letter to the Indian Minister of Environment, recommending that greater attention be paid to the potential impacts on biodiversity and offering to provide expert advice. The letter is available here.

A similar letter was sent from the Society for Marine Mammalogy (view at https://www.marinemammalscience.org/letters/presidential-letter-india-ganges-river-dolphins-waterways-development-program/).


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‘Extinction Is Imminent’: New report from Vaquita Recovery Team (CIRVA) is released

Analyses of visual sightings and acoustic detections of vaquitas during the range-wide survey last September-December have now been released, suggesting that only about 60 of these tiny ‘desert porpoises’ remain on the planet. And, despite an unprecedented effort by the current Mexican administration and its many international partners (from governments, NGOs, and academic institutions to individual scientists and schoolchildren), ​vaquitas have continued to die in gillnets set to capture totoaba – all to obtain the prized swim bladders of these large, endangered fish that, like the vaquita, are endemic to the Gulf of California. The swim bladders are destined to be smuggled out of Mexico to enter China’s massively destructive black market for what can often seem like everything that’s left of the earth’s vanishing wildlife.

​It is important to emphasize that President Peña Nieto, and especially his Environment Secretary Rafael Pacchiano, have stepped up like no previous Mexican administration to save the vaquita. Their serious, all-out efforts to stop the illegal fishing in Mexico have been undermined by intransigence on the part of Mexico’s fisheries sector together with China’s insatiable, out-of-control appetite for swim bladders.

The report from the Seventh Meeting of the Comité Internacional para la Recuperación de la Vaquita (CIRVA-7), held in early May, is now available here. It has been delivered to the Mexican Secretary of the Environment and to the IWC Scientific Committee for consideration at the annual SC meeting which begins this week in Bled, Slovenia.

 


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New film – “In search of Vaquita”

An excellent new film, called ‘Almas del Mar Vermilion: En Búsqueda de la Vaquita Marina‘ in Spanish, which describes the story of the vaquita, its decline and its conservation  is available at this link:  https://vimeo.com/166899979 and with English subtitles: https://vimeo.com/166852669

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Mekong River dolphin update

Since the last news report on this website regarding Mekong River dolphins (posted 3 July 2014), the WWF-Cambodia team based in Kratie, working in collaboration with the Fisheries Department in Phnom Penh, have continued their valiant efforts to conserve and study this small, Critically Endangered population. Some of the outcomes of their work are described here. It is great to hear that at least through March, no dead dolphins had been reported in 2016, and several calves had survived their first year of life. Also, the “river guards” program is apparently functioning well.

In late March, Frances Gulland (Wildlife Health Specialist Group) visited Kratie to carry out necropsies on five dolphins that died in 2015. She concluded that one of the two adults had died from entanglement in fishing gear; the other was too decomposed to diagnose the cause of death but it was fat and heavily scarred (typical of adults in this population). Of the three calves, two had been stillborn and one died from trauma. Efforts are ongoing and more are planned to investigate why young calves in this population have been experiencing exceptionally high mortality.


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Stronger protection needed to prevent imminent extinction of Mexican porpoise vaquita, new survey finds

Vaquita, Chris Johnson, 2008

Vaquita, Chris Johnson, 2008

Only about 60 vaquitas remain in the Gulf of California, according to a report presented this week to Mexico’s Minister of the Environment and Natural Resources and the governor of Baja California. This represents a decline of more than 92% since 1997. Unless Mexico extends the gillnet ban and enhances its strong commitment to combat illegal fishing, this small and critically endangered porpoise will be driven to extinction within five years, according to an international team of scientists established by the government of Mexico (the International Committee for the Recovery of the Vaquita, CIRVA) who met this week in Ensenada, B.C., Mexico.

Vaquita population and abundance

Vaquita population and abundance

A range-wide survey late last year confirmed earlier results from acoustic monitoring showing a catastrophic decline of vaquitas amid a resurgence of illegal gillnetting for an endangered fish, the totoaba (Totoaba macdonaldi).  Swim bladders from these fish enter the illegal wildlife trade in China, selling for thousands of dollars per kilo.

CIRVA warns that accidental drowning in gillnets is rapidly driving the vaquita (Phocoena sinus) toward extinction. Previous research showed that the vaquita had declined from around 570 in 1997 to 250 in 2008. The vaquita is the most endangered marine mammal, and indeed one of the most endangered mammals, in the world.

“We are watching this precious native species disappear before our eyes,” said Lorenzo Rojas-Bracho, chair of CIRVA and co-chief scientist of the survey. “Our latest survey confirms the catastrophic decline before the emergency gillnet ban. This gillnet ban and strong enforcement must continue if we are to have any hope of saving the vaquita.”

CIRVA praised the unprecedented conservation actions already taken to stop the impact of both illegal totoaba fishing and legal gillnetting by the government of Mexico.  The President imposed an emergency two-year ban on gillnets throughout the range of the vaquita in the northern Gulf of California beginning in May 2015. The Mexican Navy oversees enforcement and local fishing communities are receiving millions of dollars of compensation for lost income. However, CIRVA stresses that the ban must become permanent if the species is to survive and recover.

Gillnet exclusion area_CIRVA 5

Gillnet exclusion area_CIRVA 5

Rafael Pacchiano, Mexico’s Secretary of the Environment and Natural Resources, stated that federal authorities are working in a coordinated and committed manner to prevent illegal fishing of totoaba in the area that is safeguarded for vaquitas. They are also combating the illegal trafficking of protected marine species and the presence of organized criminal groups related to this activity.

“Surveillance operations were intensified, especially at night, by incorporating equipment and personnel from the Agency of Environmental Protection (PROFEPA), the Navy of Mexico, the Federal Police and the Department of Fisheries, allowing greater land and maritime surveillance during the curvina fishing season in April,” Secretary Pacchiano said.

Despite the ban, three dead vaquitas were found in March, all having died from entanglement in gillnets probably set for totoaba. Forty-two illegal nets were removed over the past four months by the enforcement team of the Navy and Sea Shepherd’s Operation Milagro.  “The lure of big money for totoaba swim bladders killed at least three more vaquitas, individuals sorely needed to prevent the species’ slide toward extinction,” said Frances Gulland of the Marine Mammal Center in Sausalito, California, who performed necropsies on two of the carcasses.

If the current ‘emergency’ gillnet ban is made permanent and, importantly, more effectively enforced, the vaquita may recover. Protection of two other Mexican marine mammal species that were at very low levels has led to recovery. “While there is good reason to expect that vaquitas could recover if deaths in gillnets were stopped.” says Barbara Taylor, co-chief scientist of the survey and a member of the recovery team, “if gillnetting is allowed to resume in the northern Gulf, the vaquita may be extinct by 2022.” Given the dire situation, CIRVA recognizes that every option must be investigated and a plan to examine the feasibility of live capture and a temporary safe haven is in place – but there is no guarantee of success. CIRVA emphasizes that this is not an alternative to a permanent enforced ban on the gillnets that kill vaquitas.

Since vaquitas are accidental casualties of gillnetting, fishing methods and markets must change to protect them. Gillnets also kill hundreds of thousands of porpoises, whales, dolphins and seals worldwide every year.  “If Mexico managed to solve this problem of vaquita mortality in gillnets, it would set an example for other nations, showing that fishermen can fish sustainably and co-exist with porpoises, dolphins, and other sea mammals,” says Taylor.

photo credit Paula A Olson (2008)

photo credit Paula A Olson (2008)

Vaquita in the northern gulf of California. Photo credit Tom Jefferson (2008)

Vaquita in the northern gulf of California. Photo credit Tom Jefferson (2008)

 


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