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
- 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
- allow portal users to request access to source data, while
leaving their provision at the discretion of each contributing
- 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
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
2. Phase I integrated analysis
- 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
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
- 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 (ongoing)
Cetacean data from the ACSOBANS extended
agreement area from governmental organisations,
non-governmental organisations and industry have been included in
the JCP analysis. Data submitted have had to meet the
- Data must be effort related and come from
within the ACSOBANS extended agreement area;
- Data must be collected at sea, during
dedicated surveys; and
- Data must be collected using one of the
- 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
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.