198 | Chapter 10
colonies,* in marine terms a modest area, which might benefit swim-
ming penguins but would be of less use to flying seabirds.
These closures were coupled with studies that used GPS- tracking to
assess how far afield parent penguins need to swim to collect food for
their chicks whose growth rate was also measured. Possibly the adults
would have to work less hard and/or the chicks would grow faster when
the adjacent fishery was closed. Although the data reported to the 2nd
World Seabird Conference were less crisp graphic and more smudged
watercolour – this was, after all, real biology! – temporary fishery clo-
sures did appear to benefit the African Penguins. That said, the benefit
to penguins was compromised by the understandable tendency of fish-
ing operations to be concentrated just beyond the closed boundary,
where very likely fish spilled out of the protected zone and rendered
fishing more rewarding.
Another part of the world where there is some, but only some, evi-
dence that seabirds have benefitted from fishery closure is the North
Sea. In the 1990s, the north- western North Sea witnessed industrial
fishing for sand eels, wriggling silver slivers that were transformed into
fish meal for feeding livestock. This was associated with declines in
the breeding success of seabirds breeding on Scotland’s east coast and
known from radio- tracking and satellite- tracking to be searching for
sand eels for their chicks in the very fishery area. When the fishery was
in full swing, the breeding success of Black- legged Kittiwakes fell, only
to recover when closures were imposed in 2000. For other species, such
as Razorbills and Atlantic Puffins, fishery closure provided no detect-
able benefit, perhaps because these species could hunt many metres un-
derwater, in contrast to the surface- feeding Kittiwake.^25 However, the
past decade has seen a continuation of the sand eel decline, not because
of fishing but probably because of the sea’s warming which compro-
mises the ability of young sand eels to survive the winter while hibernat-
ing in sandy seabeds.
- (^) An intention for the closure radius to be 20 nautical miles (nm), almost twice as great as the
achieved 20 km, was lost during the passage of the necessary legislation. A cynic might notice
that the proximity of k and n on a standard keyboard would increase the chance of a transcrip-
tion error.