Amazon River dolphins in Brazil continue to be killed for fish bait

It has been known for some time that fishermen have been killing freshwater dolphins in the Amazon and using them as bait for catfish (Mintzer et al. 2013; Iriarte & Marmontel 2013; Brum et al. 2015).  A recent report from Brazil found that following the decline of a regional delicacy, the catfish species called the ‘capaz’ (Pimelodus grosskopfii), fishermen started targeting a different catfish species, known in Brazil as ‘piracatinga’ and in Colombia as ‘mota’ (Calophysus macropterus), that is traditionally disliked by Brazilians because it is a scavenger (Cunha et al. 2015). DNA analysis by Cunha et al. revealed that this fish is being marketed under a variety of fictitious names including ‘douradinha’. River dolphin carcasses provide ideal bait for attracting large numbers of the carrion-feeding piracatinga. Indeed, the presence of dolphin tissue in piracatinga stomachs was confirmed by mtDNA control region sequencing (Cunha et al 2015).

Foetus of an amazon river dolphin being pulled from its mother

Foetus of an Amazon river dolphin being pulled from its mother as she is chopped up for catfish bait. Photo Credit: Alerta Vermelho (www.alertavermelho.org.br)

This use of dolphins as bait is directly linked to dramatic declines in dolphin populations in parts of the Amazon. A 5-year legal moratorium on fishing for piracatinga came into force in Brazil on 1 January 2016. Although the legal text justifying this temporary ban refers to implications for human health (piracatinga have high levels of mercury in their tissues), the trigger for passage of the act was public outrage over the killing of dolphins to supply bait. However, despite the ban, the trade in piracatinga in Brazil continues and therefore dolphins continue to be killed. Observations by scientists studying the dolphins in the central Amazon indicate that enforcement is weak and that the dolphins (and caimans) are still greatly threatened, at least in some large parts of their range.

Brum, S.M., V.M.F. Silva, F. Rossoni and L. Castello. 2015. Use of dolphins and caimans as bait for Calophysus macropterus (Lichtenstein, 1819) (Siluriformes: Pimelodidae) in the Amazon. Journal of Applied Ichthyology 31(4):675-680.

Cunha, H.A., V.M. da Silva, T.E. Santos, S.M. Moreira, N.A. do Carmo and A.M. Solé-Cava. 2015 When you get what you haven’t paid for: molecular identification of “douradinha” fish fillets can help end the illegal use of river dolphins as bait in Brazil. Journal of Heredity 106(S1):565-572.

Iriarte, V. and M. Marmontel. 2013. Insights on the use of dolphins (boto, Inia geoffrensis and tucuxi, Sotalia fluviatilis) for bait in the piracatinga (Calophysus macropterus) fishery in the western Brazilian Amazon. Journal of Cetacean Research and Management 13(2):163-173.

Mintzer, V.J., A.R. Martin, V.M. da Silva, A.B. Barbour and K. Lorenzen and T.K. Frazer. 2013. Effect of illegal harvest on apparent survival of Amazon River dolphins (Inia geoffrensis). Biological Conservation 158:280-286.

 

Arabian Sea humpback whales are one of only four populations still considered Endangered under the United States revised Endangered Species Act listing.

*This article is a re-post of a recent WWF media release http://wwf.panda.org/wwf_news/?278471/Arabian-Sea-humpback-whales-one-of-only-four-populations-still-considered-endangered-after-lengthy-US-review

Following an extensive review process that started in 2009 and was finalized in September 2016, the United States’ National Oceanic and Atmospheric Administration has revised the status of humpback whale populations around the world under the US Endangered Species Act (ESA).  The modified listing recognizes the Arabian Sea population as one of only four humpback whale populations around the globe that is not recovering from historical whaling, and is at high risk of extinction without serious conservation efforts.

Humpback whale off the coast of the Sultanate of Oman ©Environment Society of Oman

Humpback whale off the coast of the Sultanate of Oman ©Environment Society of Oman

A Biological Review Team examined hundreds of scientific studies and reports that demonstrate how the majority of humpback whale populations around the world are increasing following the International Whaling Commission’s ban on commercial hunting of this species in 1966.  Careful consideration led to the designation of fourteen “Distinct Population Segments” (DPS), nine of which are no longer considered to be in immediate danger of extinction, and have thus been “de-listed”.  A DPS is treated equivalent to a species under the ESA.

However, five populations have not shown the same signs of increase toward recovery, and are still listed as Endangered or Threatened.  Of these, the Arabian Sea population is the smallest, most distinct, and most at risk.  Its range is believed to extend from the coasts of Yemen and Oman in the west to Iran, Pakistan and India in the east.

The notice states: “The Arabian Sea DPS faces unique threats, given that the whales do not migrate, but instead feed and breed in the same, relatively constrained geographic location. Energy exploration and fishing gear entanglements are considered likely to seriously reduce the population’s size and/or growth rate, and disease, vessel collisions, and climate change  are likely to moderately reduce the population’s size or growth rate….. The…. Arabian Sea DPS [is] in the ‘at high risk of extinction’ category.”

 

Map showing the 14 humpback whale Distinct Population Segments (DPS) now recognized under the United States’ Endangered Species Act. Of the four populations that remain Endangered, the Arabian Sea population (number 14 on this map), is considered the most distinct and the most likely to become extinct without conservation intervention. Source: http://www.nmfs.noaa.gov/pr/species/mammals/whales/humpback-whale.html

Map showing the 14 humpback whale Distinct Population Segments (DPS) now recognized under the United States’ Endangered Species Act. Of the four populations that remain Endangered, the Arabian Sea population (number 14 on this map), is considered the most distinct and the most likely to become extinct without conservation intervention. Source: http://www.nmfs.noaa.gov/pr/species/mammals/whales/humpback-whale.html

The Biological Review Team that conducted the 6-year long review process considered evidence from the Arabian Sea that includes information on illegal hunting of whales by Soviet whaling fleets in the 1960’s, fifteen years’ worth of dedicated whale research off the coast of Oman, and a few opportunistic sightings and strandings of whales along the coasts of Pakistan and India.  Data from Oman provide evidence that the population is extremely small, numbering fewer than 100 individuals, and confirm the Soviet whalers’ speculation that Arabian Sea humpback whales comprise the only non-migratory population of humpback whales in the world.  Genetic evidence shows the population to be distinct and no longer in breeding contact with any other humpback whale populations in the Indian Ocean.

These factors, coupled with ever-increasing threats from entanglement in fishing gear, strikes by vessels in some of the world’s busiest shipping lanes, and noise from shipping, coastal development and offshore oil and gas exploration, are cause for serious concern.  The population also has high levels of liver abnormalities and skin disease, which may render them more vulnerable to other diseases or stressors. Furthermore, this non-migratory population, restricted to the “cul de sac” of the Arabian Sea, has no alternative feeding or breeding grounds should climate change or an environmental disaster on the scale of the Deepwater Horizon irrevocably change the dynamics of their limited habitat.

engangled-whale-off-oman-2A humpback whale entangled in a gill net off the coast of Oman (© Environment Society of Oman).

A humpback whale entangled in a gill net off the coast of Oman (© Environment Society of Oman).

While the Endangered Species Act most directly affects whales present within US waters, it also applies on the high seas to any vessels or persons under US jurisdiction.  The notice states that while the International Whaling Commission (IWC) and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) provide significant protections to all large whales, there are no formalized governmental or inter-governmental conservation efforts for the Arabian Sea humpback whale.  To address the lack of coordinated effort to save this population from extinction, whale researchers and conservation organisations from Arabian Sea range states have joined together in the Arabian Sea Whale Network.  Very much a grass-roots initiative, this network strives to support whale research and conservation efforts in the region.  Together with the Wildlife Conservation Society (WCS), The Environment Society of Oman and the US Marine Mammal Commission, WWF has played a critical role in supporting the formation of this network.

Network members in Pakistan, India, Oman and Iran are conducting research to better describe the range and status of the population and working with local stakeholders to mitigate threats, but they lack sufficient funding.  As a result, we know almost nothing about the whales’ current distribution, numbers, or specific habitat needs in their suspected range outside of Oman. Funding is also needed at a regional level to support training and awareness-raising at all levels, and to better coordinate collaborative research and conservation work. Overall, without significant governmental efforts and stakeholder involvement to reduce the threat of whale entanglement in fishing gear along all the coastlines of its range and to address the risk of ship-strike in corridors of high shipping activity, the outlook for the Arabian Sea humpback whale population looks bleak.  Cooperation has been successful in other regions of the world as in the ongoing efforts to conserve gray whales in the western Pacific. Only through collaboration by governments, NGO’s, IGO’s, industry and other relevant stakeholders can we hope to overcome the odds and address the threats to Arabian sea humpback whales.

For more information, contact Arabian Sea Whale Network coordinator Gianna Minton  (gianna.minton@gmail.com) or look at our website:  https://arabianseawhalenetwork.org/

 

 

Latest SMM Taxonomy Committee List of Marine Mammal Species Includes Several Species-level Changes

By Thomas A. Jefferson and Patricia Rosel

The Society for Marine Mammalogy’s Committee on Taxonomy publishes a list of marine mammal species of the world and updates it annually.  Recent revisions include many changes at the subspecies level, but here we summarize only species- or genus-level changes.  A ‘new’ whale (actually not new, but a resurrected species), Mesoplodon hotaula, has been added to the list.  The humpback dolphin genus Sousa has been split from two species into four, including the resurrection of S. plumbea (Indian Ocean humpback dolphin), and the addition of a new species, S. sahulensis (Australian humpback dolphin).  Perhaps the most interesting change for many marine mammalogists is the dropping of Delphinus capensis as a recognized species and the resultant lumping of all common dolphins of the world back into the single species D. delphis.  This can be viewed as a provisional change, as work is underway to determine if the eastern North Pacific long-beaked common dolphin, qualifies as a distinct species (or only as a subspecies as it is currently listed).

Some recently proposed species are not on the current list, mostly due to conflicting evidence or the lack of strong evidence for their distinctiveness at the species level.  These include Inia boliviensis, Inia araguaiaensis, and Tursiops australis.   Future work may clarify the status of each of these.  Finally, while it is recognized that several genera of dolphins are paraphyletic or polyphyletic, and thus not good phylogenetic taxa, no taxonomic changes will be made to the list until further work can clarify how best to deal with these ‘problematic’ genera – Lagenorhynchus, Stenella, and Tursiops.

For more details, consult the latest version of the list at: https://www.marinemammalscience.org/species-information/list-marine-mammal-species-subspecies/.  Thanks to Bill Perrin for his many years of service as Taxonomy Committee chair.  Patty Rosel will be taking over from Bill as the new chair.

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