Young Gray Whale Sighted near Tokyo Islands

In March 2015 a young gray whale visited waters near Kozushima and Niijima, part of Tokyo’s outlying Izu Islands group. The occasional appearance of gray whales, such as this one, in Japan, together with a stranding on the mainland China coast of Taiwan Strait in November 2011, indicate that although some of the whales that feed in summer off Sakhalin Island (Russia) migrate to wintering areas off North America, some gray whales still use other traditional portions of their historical habitat in East Asia (see Weller et al. 2012 at http://www.int-res.com/articles/feature/n018p193.pdf).

Photo Caption: Young gray whale observed near Kozushima, Japan, on 20 March 2015. Photo by Nana Takanawa.


Finally: Announcement from Mexico on Vaquita Conservation

After months of anticipation, on 23 December 2014 the Government of Mexico finally released its official response to the recommendations of the July 2014 meeting of the international vaquita recovery team (Comité Internacional para la Recuperación de la Vaquita, CIRVA-5); see details in our News Item from August 2014. This took the form of a Regulatory Impact Statement (MIR de Impacto Moderado in Spanish) issued by the fisheries agency through the Ministry of Agriculture, Livestock, Rural Development, Fisheries and Food (SAGARPA) (click here for the MIR). The MIR, along with a draft Agreement between the Ministry of Environment and Natural Resources (SEMARNAT) and SAGARPA (to read click here), was open briefly for public comment and is expected to come into force soon.

Key elements of the plan include:

  • A complete ban for two years on the use of gillnets in the exclusion zone proposed by CIRVA.
  • An exemption from the ban for the Gulf corvina fishery during the period 1 February to 30 April. This fishery targets spawning aggregations of a large croaker using a ‘rodeo’ or ‘round-up’ technique that encircles the fish with large-mesh gillnets, actively fished.
  • Compensation to all‎ fishermen and others who work in fishery-related activities (e.g. workers in shrimp packing plants).
  • Creation of community enforcement groups to assist authorities in policing the gillnet ban.

CIRVA has provided comments on these documents, explaining some of the strengths and weaknesses of the Government’s plan (to read the comments in English, click here).

There is no doubt that this announcement represents a step forward. However, as indicated in the 7 December 2014 news item posted on this website, intensive gillnet fishing has continued both inside and outside the Vaquita Refuge, with no evidence of a significant effort to enforce existing regulations. Valuable time has been lost, and there is no way of knowing how much closer this has driven the vaquita toward extinction.



Potential new breeding area revealed for critically endangered Baltic Sea harbour porpoises

The critically endangered vaquita (see news item below) is not the only cetacean seriously threatened by gillnet entanglement. The small subpopulation of harbour porpoises (Phocoena phocoena) in the Baltic Sea has been drastically reduced, initially by large historical commercial catches in the Danish Straits and more recently by incidental mortality in fishing nets, primarily set and drifting gillnets. Other threats probably exist but are not well understood. Baltic Sea harbour porpoises are red-listed as Critically Endangered (click to see assessment).

The need for improved methods of collecting data on Baltic Sea porpoise numbers and range, and how these change over time, led to initiation of the Static Acoustic Monitoring of the Baltic Sea Harbour Porpoise (SAMBAH) project. which involved all EU countries bordering the Baltic Sea.  The overall objectives of the project were to develop and implement a best practice methodology and provide data for reliably assessing porpoise distribution and habitat.

Porpoise echolocation signals were recorded by acoustic data loggers called C-PODs deployed at 304 locations in waters 5-80 m deep throughout the Baltic Sea, making it one of the largest projects of its kind in the world – a huge collaborative effort. The project is now complete and the results have been released.

The number of harbour porpoises in the Baltic Sea was estimated as 447 (95% confidence interval 90–997). Seasonal distribution maps (see below) show a clear spatial separation of populations in the Baltic Proper and in the Western Baltic during May-December when the porpoises mate, give birth and nurse their calves. Spatial modelling of the acoustic data revealed a major breeding area of the Baltic Proper population around the Midsjö banks southeast of Öland, where the presence of porpoises had been virtually unknown previously.

Image Caption: Dots indicate positions of acoustic data loggers (C-PODs) that recorded harbour porpoise echolocation signals in January-April, and May–December 2011 and 2012, combined. The line indicates the likely seasonal division between the population in the Baltic Proper and porpoises in waters to the west.

The combination of the new (albeit very imprecise) population estimate and the new information on porpoise distribution in space and time within the Baltic is expected to enable dedicated conservation action in areas where it is most needed. Also, the methodologies developed by the project offer new possibilities for assessing porpoise densities elsewhere using passive acoustics.

 


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