IUCN – SSC Cetacean Specialist Group

The Cetacean Specialist Group promotes and facilitates
The Cetacean Specialist Group promotes and facilitates

The Cetacean Specialist Group promotes and facilitates
The Cetacean Specialist Group promotes and facilitates
The Cetacean Specialist Group promotes and facilitate

Urgent Letter sent from IUCN Species Survival Commission to Mexican Authorities to correct false information about vaquita decline

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Last week, the IUCN Species Survival Commission sent a letter (see version in Spanish, and English) to the Secretaries of the Mexican Navy, Environment, and Agriculture and Fisheries authorities, to counter false allegations that vaquitas are going extinct because of a change in salinity within the vaquita habitat.  According to the allegations, shark predation and osmoregulation failure are the causes of the vaquita’s precipitous population decline. No scientific evidence (in the form of peer-reviewed scientific articles or data) has been provided to support these allegations and the SSC acted quickly to dispel the rumours, and make clear that the only immediate threat to the species is accidental mortality in gillnets.  The letter’s main objective was to emphasize this, and to do so quickly, as March is the peak of the totoaba poaching season when entanglement risk to vaquitas is greatest. It requests that Mexican authorities take immediate action to reinstate net-removal activities, which are currently on hold, as soon as possible. Scientific evidence to refute the allegations is given in the letter.

2 updated cetacean red list assessments published in March 2021

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The 2021-1 edition of the Red List, which was published in March 2021, included two updated cetacean assessments. This is in addition to the 22 assessments published in December 2020, 3 earlier in 2020, 6 in December 2019, 2 in July 2019, 5 in March 2019, 35 in November 2018, 10 in July 2018, and 19 in November 2017. A total of 104 updated or new cetacean assessments have now been published in the last 2 ½ years.

 

One of the two 2021-1 updated assessments was of the common dolphin (Delphinus delphis) and it reflects the recent change in taxonomy for this species group (see Committee on Taxonomy), combining all common dolphin forms into a single assessment as Least Concern.  The northern bottlenose whale (Hyperoodon ampullatus) was moved from Data Deficient to Near Threatened in the newly published updated assessment of that species.  Work on the remaining two cetacean species that require updating (sperm whale and Hector’s dolphin), and on some of the more out-of-date subpopulation and subspecies assessments, will continue in 2021.

 

Table 1 – Summary of updated assessments and new assessments published in the 2021-1 edition of the Red List. (NT = Near Threatened, DD = Data Deficient, CR = Critically Endangered, EN = Endangered, LC = Least Concern).

# Species/Subspecies Common name Taxonomic level Category Status change
1 Delphinus delphis Common dolphin Species (global) LC No change
2 Hyperoodon ampullatus Northern Bottlenose whale Species (global) NT DD -> NT

 

The Red List status and documentation for 90 cetacean species as well as 12 subspecies and 28 subpopulations can be found on the IUCN Red List website (redlist.org).  Of the 90 species, 24% are assigned to a threatened category (i.e. CR, EN, VU), 11% are Near Threatened, just over half (54%) are Least Concern, and 10% are considered DD (Table 2). It should also be emphasized that there is strong interest in completing additional assessments of subpopulations that are known or thought to be at higher risk than the species as a whole (e.g. killer whales, belugas, dusky dolphins).

 

Table 2. Summary information on Red List status as of March 2021.

Category Species Subspecies Subpopulations Total
Critically Endangered 4 4 14 22
Endangered 11 4 7 22
Vulnerable 7 4 5 16
Near Threatened 10 0 0 10
Least Concern 49 0 0 49
Data Deficient 9 0 2 11
Total 90 12 28 128

 

 

 

Successful release of an entangled humpback whale in Duqm Port, Oman

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Photo credit:  Ada al Jabri, Oman Environment Authority

 

On the evening of January 18th, 2021, staff at the Environment Authority – Oman (EA) were notified that  an Endangered Arabian Sea humpback whale was entangled in fishing gear inside the Port of Duqm. The whale apparently had been trapped for days, with net and line wrapped inside its mouth and around the flippers, dorsal fin and tail stock. This situation was immediately recognised as a significant risk for both the whale and Port operations.

 

Recalling the entanglement response training that had been conducted by the International Whaling Commission (IWC) in Oman in 2015, specialists from the Environment Authority, Five Oceans Environmental Services LLC (FOES) and Future Seas Global SPC, supported by the Environment Society (ESO) and the Port of Duqm, quickly mobilised a team and equipment to travel from Muscat to Duqm, reaching the Port on the following day.  With assistance and personnel from Oman’s Coast Guard, Royal Air Force of Oman (RAFO) and the Port of Duqm, as well as real-time advice from members of the IWC disentanglement expert panel, the team spent the afternoon of the 19th initiating disentanglement.

 

Click here to watch a video clip of the response.  This shows the team in the day’s last light, attaching buoys to slow the whale down and the prevent it from diving while the team was working to remove the net. During this intervention, the team noted that as the whale attempted to dive, the upwards force of the buoy helped to unwrap rope and net from the mouth, followed by more rope being dislodged from the flippers and area around the dorsal fin. By the end of the day it was apparent that the only net remaining was on the tail stock.

 

Video and photographs of the whale during the disentanglement allowed the research team to recognise it as one of the individual whales catalogued in a long-term photoidentification study that has been undertaken in Oman since the year 2000. The whale was identified as individual ‘OM11-016’, which was first photographed near the Port of Duqm in 2010, and then again further south near Hasik in 2011 and 2014.  Most recently this whale had been observed again just outside Duqm Port in October 2020.

 

On January 20th, when the rescue team returned to the scene to continue the disentanglement, the whale was no longer in the port. Neither a search of the immediate area using port pilot vessels nor a helicopter search by the Royal Air Force of Oman detected the whale. However, video shared by a coastguard vessel showed a whale swimming freely in the port later on the day of the 20th. Although the video footage did not allow for definitive identification, the habitual appearance of this whale in the port over the last 3 months, the absence of detections during the aerial search, and the observations of the net unwrapping on the previous day all led the team to conclude that this was likely the same whale, and that the actions taken on the 19th had enabled the animal to shed the rest of the gear and swim free.

 

With fewer than 100 individual humpback whales believed to remain off the coast of Oman, the incident highlights a number of issues of critical importance to efforts to protect the regional humpback population and prevent its extinction:

 

  • Published research, satellite tracking data, and the sighting history of OM11-016 and many other whales in the Oman catalogue indicate that whales have a strong affinity for the Gulf of Masirah and the approaches to Duqm Port.
  • This highly productive area is also a known hotspot for intensive artisanal fishing, with some vessels (referred to locally as dhows) used to set gillnets similar to that found on the entangled whale. These nets are regularly set within the core feeding grounds of humpback whales and are intended to catch large finfish that feed on smaller fish like sardines, which are humpback prey.
  • Similar gillnets are used throughout the Arabian Sea by registered legal fishing fleets as well as illegal, unregulated and unreported fleets. Scientists in the Arabian Sea Whale Network have reported entanglements off Oman, Pakistan, Iran and Somalia. In some of these incidents, fishing crews have attempted disentanglements that are extremely dangerous, such as hanging from ropes and entering the water with whales, highlighting the need for more training and guidance throughout the region.
  • A recent study found that 67% of humpback whales photographed off Oman have scars on their tail stock consistent with entanglement.
  • Ship strikes represent a persistent threat to Arabian Sea humpback whales and other whale species in the region. FOES spent 3 years working with the Port of Duqm to develop and implement a Whale Management and Mitigation Plan, something that could be adapted for application to other ports in the region. Click here to see one of the key outreach tools used in this plan.

A photo shared on social media of a fisherman from an Iranian vessel operating off the coast of Somalia, attempting an extremely dangerous rescue of a female humpback whale as a calf swims nearby.