The North Atlantic Marine Mammal Commission
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Trans North Atlantic Sightings Survey - TNASS - [t'i:] [n'ęs]

TNASS areas

TNASS aims at estimating the summer distribution and absolute abundance of cetacean populations in the North Atlantic between approximately 40°N to 80°N and between Norway and Canada. The synoptic trans-Atlantic overview over the largest area ever covered by a coordinated survey (over 1,600,000 nm2) will represent a considerable enhancement of our understanding of cetacean populations in the North Atlantic, and especially its Arctic part.

Comparison with previous North Atlantic Sighting Surveys (1987, 1989, 1995 and 2001) will provide information on trends in abundance and changes in distribution over a 20-year period. Trends in abundance provide a stronger scientific basis than single estimates for management programmes aiming at maintaining the sustainability of cetacean populations subject to human removal. The information will be used directly in the management programs of NAMMCO (North Atlantic Marine Mammal Commission), the IWC (International Whaling Commission) and national agencies to determine sustainable levels of removal (direct, by-catch or other).

observer at work
Observer at work.

TNASS also takes advantage of other surveys occurring in the same period in adjacent areas (ICES Redfish, Russian-Norwegian pelagic and ECO-MAR surveys, called TNASS extension) to increase the coverage by approximately 400,000 nm2 and obtain better information on distribution and relative abundance.

Simultaneously and in coordination with T-NASS the European and the American waters, south-east and southwest of the TNASS area, will be covered by the European CODA, coordinated by the Sea Mammal Research Unit, and the American SNESSA, coordinated by the NMFS - Woods Hole.

The project is scheduled to run for 31 months in 2006-2008. The abundance survey will be conducted around July 2007 and the present budget is 4,200,000 €.

Survey methods will be standardized among platforms and participating countries. Six dedicated vessels and four planes will use standard line transect and/or cue counting methods, incorporating state of the art methods successfully implemented under the EU SCANS-II project (LIFE Program).

In addition to the production of scientific reports, articles and conference presentations, TNASS includes a plan for dissemination to the general public, with a website active during the survey, the distribution of a non technical report, press releases and a possible documentary film.