the clash | 187of 300 adult gannets a month, or 1,500 over the course of a Bass Rock
breeding season, if two proposed farms were constructed.
Twice a day, tides ebb and flow over the seabed. There is the prospect
of generating immense quantities of electricity via turbines anchored to
the seabed, and this could be especially important in Scotland, poten-
tially the beneficiary of one- quarter of Europe’s tidal power. Conceptu-
ally the problem facing a seabird underwater is similar to that presented
by wind farms to a flying bird. It can avoid the area altogether, it can
bypass individual turbine arrays or it can play chicken, probably an oxy-
moron, and avoid a collision at the very last moment. Actually under-
standing the risk needs information on the underwater behaviour of
auks, cormorants, and other diving species when near turbines. Critical
behavioural information includes data on dive depth, duration and fre-
quency, descent and ascent speeds, precisely the sort of information that
is fast becoming available from depth recorders and accelerometers.
***
Fishing is likely to be most efficient wherever and whenever the target
prey, be they fish or squid or swarming krill, are most concentrated.
That is as true for birds as it is for human fishers. In the tropics the
booby is alert for other boobies or perhaps noddies diving over a shoal
of small fish seething in terror above a school of tuna. If the booby is
quick it will be able to seize the moment – and the prey – before the
shoal disperses. If the fisher is quick, there will be time to position a
seine net in a circle around the tuna, scoop the school, and then smile
broadly as the quivering fish, a ton of dollars, slide across the fishing
vessel’s deck into the ice.
Since fishers and birds are likely to be exploiting the same sea areas,
there is every possibility of interaction at many levels. Even with an
array of detection devices on the bridge, a shrewd captain is likely to
watch birds as a further means of guiding his vessel towards fish. And
the modern captain of a tuna purse seine boat may well be eyeing his
radar to use bird echoes to guide him towards the tuna. This is exactly
the practise of French captains in the Indian Ocean.