Joint Cetacean Protocol


JNCC advocates an international cooperative approach for long term surveillance and monitoring of cetaceans in UK waters and the wider northeast Atlantic and is leading a collaborative project*, the Joint Cetacean Protocol (JCP), which will deliver information on the distribution, abundance and population trends of cetacean species occurring in this area. The JCP will build on the cetacean sightings datasets utilised in the Atlas of cetacean distribution in north-west European waters and aims to:


Short-beaked common dolphins

  • provide cetacean summary information, via a web-based portal, including species specific estimates of cetacean density, distribution and population trends;
  • create a standard structure for sharing cetacean sightings data;
  • allow portal users to request access to source data, while leaving their provision at the discretion of each contributing organisation;
  • assist with reporting on cetacean conservation status to various Directives including the EC Habitats and Species Directive and Marine Strategy Framework Directive.


The work to produce robust estimates of cetacean density, distribution and population trends has been split into four separate analyses:


1.    Preliminary analysis (complete)


  • This short study aimed to determine whether the final JCP data resource would have sufficient power to detect trends in distribution and abundance
  • It concluded that the Habitats Directive monitoring objective of detecting a 1% annual decline in abundance or range over a 6 year reporting period was not feasible but that trend detection over longer periods should be.
  • An  integrated analysis of all JCP data was recommended.




2.    Phase I integrated analysis (complete)


  • This aimed to standardise and combine a representative sample of JCP datasets, from the Irish sea, and use modelling approaches to predict density and detect spatial and temporal trends in derived abundance estimates.
  • Detection functions were fitted to all available survey sightings data that recorded distance from observer to sighting, and detection probability was calculated. These detection probabilities were then assigned to all sightings data including those without distance estimation.
  • Density estimates were then calculated for each segment of survey effort and the resultant density surfaces were modelled in a two stage GAM process by modelling presence-absence data followed by non-zero density.
  • A power analysis of the modelled density data showed that declines of 0.3 to 2.2% per year, over a 6 year reporting period, could be detected for harbour porpoise, common bottlenose dolphin and short-beaked common dolphin. However, this is only likely to be possible in data rich areas, such as the Irish Sea and Moray Firth, and for more commonly occurring cetacean species.
  • A data standard was suggested for future JCP data and this has now been finalised.




3.   Phase II (complete)


  • The methods described for Phase I required further development and a more detailed analysis of Irish Sea data, with a geographic extension to include data from parts of the west coast of Scotland, was conducted.
  • The west coast geographic extension allowed modelling methods to be tested in a region with a convoluted coastline, allowing methods to be developed that were more applicable for using on the entire geographical range of the JCP dataset.
  • these methods have been now been finalised and a final phase, which will include all relevant JCP datasets, has been implemented.




4.   Phase III (complete)


  • The JCP Phase III analysis produced species specific density surface, geo-referenced, data that faithfully reflected the spatial patterns of the input data; however, the estimated densities were higher than those previously published for similar areas (e.g. by SCANS-II and CODA). In some cases, these were considerably higher and also possibly unrealistic, particularly for species that tend to occur in large aggregations.
  • These higher than expected estimated densities and abundance may be related to problems in correcting for animal availability at the surface or to extrapolation issues.
  • The JCP Steering Group have , therefore, agreed to a re-run of the analysis which aims to address the above issues.


5. Phase III Revised (complete)

  • The report from this analysis was published in March 2016.


Cetacean data from the ASCOBANS extended agreement from governmental organisations, non-governmental organisations and industry have been included in the JCP analysis. Data submitted have had to meet the following requirements:


  • Data must be effort related and come from within the ASCOBANS extended agreement area;
  • Data must be collected at sea, during dedicated surveys; and
  • Data must be collected using one of the following methods:

- Line transect without distances to sightings;

- Line transect with sighting attributed to distance bands;

- Line transect with distance and bearing to sightings; or

- Double platform method

- Plot sample, such as a strip transect.


If you want to submit data to the JCP, or for further information on the project, please contact Tim Dunn


* with Countryside Council for Wales; Sea Mammal Research Unit; Department of the Environment, Heritage & Local Government; The Crown Estate; University College Cork;  Irish Whale and Dolphin Group; Sea Watch Foundation.