Humpback Whales off Wexford Coast...

During the closing stages of last week we received reports of Humpback Whale sightings off the Wexford coast...

...since that time confirmed sightings have been made by observers of a number of Humpback Whales off the County Wexford coast indulging in what is a fairly common behavioural activity for this species - launching themselves high out of the water in spectacular breaches, returning to the water with an enormous splash.

Both in 2009 and in 2004 when we had significant numbers of Humpbacks off the southwest coast, we encountered breaching animals. The charismatic Humpback Whales is one of only two species of baleen whales in Irish waters which may be encountered regularly breaching, the other being the much smaller Minke Whale.

One of the many questions we have fielded during the last two days has been "where have these animals come from and where are they going". Whilst the migratory patterns of Humpback Whales in the eastern Atlantic remain the subject of much conjecture some information is well documented...

The migratory patterns of large baleen whales in the northern hemisphere cover lesser distances than those same species in the southern hemisphere. However, the Humpback Whale may be the one exception to that rule. Well studied, large Humpback Whale populations off the eastern seaboard of the United States, demonstrate migrations that see individuals travelling from Greenland to the Dominican Republic every year to calve and mate, returning to northern climes to feed in the nutrient rich waters off Greenland and the Denmark Straight.

Humpback populations in the eastern Atlantic are much smaller and are believed to travel between Icelandic and Norwegian waters and Greenland and traditional breeding grounds around The Cape Verde Islands, off the west African coast. The number of animals observed at any one time around the Cape Verde Islands however, number far less than the estimated total population of Humpbacks in north eastern Atlantic waters leading some observers to believe that some members of this population travelled across the Atlantic diagonally to the waters around the Dominican Republic. This is supported by the finding that an individual first identified in the Denmark Straight was identified nearly 18 years later in the waters of the Cape Verde Islands suggesting some "diagonal" west - east migration does occur. It is reasonable to assume that east - west "diagonal" movement occurs as well.

Given that concentrated Humpback activity is not a year round phenomenon off any part of the Irish coastline it is reasonable to assume that these individuals off Wexford are part of a general north - south migratory movement of Humpback Whales that occurs during the winter months opportunistically feeding on seasonal Herring spawning aggregations that occur of the southeast corner of Ireland during the winter months.

To be sure we would need clear photo identification showing animals off Wexford were the same individuals seen in both north east Atlantic waters and around the Cape Verde Islands. So far that type of conclusive evidence is not available.

ENDS