Mari­ne bio­lo­gists have for the first time made a com­ple­te cen­sus of Belu­ga wha­les in Spits­ber­gen to get a pre­cise esti­ma­te of the popu­la­ti­on. The result was made available on Rese­arch­ga­te in Febru­ary.

The sci­en­tists around the Nor­we­gi­an mari­ne bio­lo­gist Chris­ti­an Lyder­sen have made aeri­al sur­veys of the coast­li­nes of almost all islands in Sval­bard. Addi­tio­nal­ly, they have cover­ed the open water are­as of the lar­ge fjords on the west coast and indi­vi­du­al tran­sects out towards the open sea to get an over­view as com­ple­te as pos­si­ble.

Belu­ga wha­le in Dick­son­fjord. Lar­ge groups are very dif­fi­cult to count. The­re is only one in the pic­tu­re, but how many did we see within 5 km or so around it? Dozens? Hundreds?

The result is inde­ed sur­pri­sing: 22 groups with a total of 265 ani­mals were sigh­ted. Sta­tis­ti­cal cal­cu­la­ti­ons result in a popu­la­ti­on esti­ma­te of 549 White wha­les for the who­le Spits­ber­gen archi­pe­la­go (95 % con­fi­dence inter­val: 436-723).

The­re are, of cour­se, remai­ning uncer­tain­ties. More ani­mals than esti­ma­ted may have remain­ed invi­si­ble during the sur­vey. But even if you increase the result based on a hig­her esti­ma­te of unseen indi­vi­du­als, it remains sur­pri­sin­gly low. Until now, all the­re was was rough esti­ma­tes based on obser­va­tions which were more punc­tu­al in space and time. The­se may have been cor­rupt­ed by the migra­tio­nal beha­viour of White wha­les, which often seem to cir­cle around in cer­tain are­as for a while, giving an obser­ver who remains in one place on the coast the impres­si­on that one group is moving through after the other.

It is also so far unknown if the­re is a con­nec­tion to Belu­ga wha­les in Frans Josefs Land (Rus­si­an Arc­tic). If Spits­ber­gen and Frans Josefs Land share a popu­la­ti­on, as is the case with polar bears and wal­ru­ses, then it would again be a com­ple­te­ly dif­fe­rent pic­tu­re. But the few data that are available from track­ing Belu­ga wha­les do not sup­port this, but it can cer­tain­ly too ear­ly to exclude this hypo­the­sis.