76
M. Puch . J. Larsen
7.2.3
Monitoring of Fish
The construction work must not block the migration of Rugen herring through the
0resund. When this criteria was set, consideration was also made for a number of other
fish species, such as eel, garfish and lumpsucker, which also use the 0resund as a migration route. The herring which spawn in the western Baltic use the 0resund as their
most important migration route between their summer feeding grounds in the Skagerrak
and their spawning ground. The monitoring carried out has shown that the herring
move into the 0resund from the Kattegat during the early autumn (August-September), with large parts of the breeding stock spending the winter there, mainly in the
deeper areas around Ven. During the spring months there is rapid migration from the
0resund (completed in March) towards the spawning grounds in the western Baltic.
Mter spawning the herring migrate back to the Skagerrak, but the 0resund is not their
only route back.
During the migration seasons of 199511996 and 199611997 a monitoring cruise was
undertaken in the autumn which showed that the herring had migrated into the 0resund
and were present in concentrations which corresponded to what had been seen during
the baseline studies in 1993-1995. Monitoring expeditions during the spring showed
that the herring had left the 0resund for the spawning grounds as expected.
In addition to monitoring cruises this programme also includes continuous logging
of the passage of shoals of herring through Drogden. The equipment for this was adjusted during the spring of 1996 and has been in operation since the beginning of June
1996. Several passages of shoals of herring were recorded during this period.
7.2.4
Monitoring of Birds
A reduction of 15% in the population of breeding eiders (Somateria mollissima) on
Saltholm is acceptable, but no later than 5 years after seabed work is completed the
number of breeding pairs must be at least 90% of the number of breeding pairs counted
during the baseline studies. As far as other breeding waterfowl on Saltholm are concerned, there must not be a significant reduction in numbers. A temporary reduction
in the number of foraging and resting migratory birds on Saltholm as a consequence of
the construction work can be accepted. However, it is expected that the number of birds
will be re-established no more than 2 years after the completion of the construction
work. As far as greylag geese (Anser anser) and mute swans (Cygnus olor) are concerned, it is accepted that there is a risk of a permanent decline in the number of moulting
birds.
As part of the programme, studies have been made of overwintering, breeding and
moulting birds, partly at Saltholm and partly on the Swedish coast between Landskrona
and Falsterbo. Owing to the hard winter of 199511996 and heavy ice formation, including inland waters, the numbers of diving ducks in the 0resund in January and Februarywere large, particularly at the future bridge abutment at Lernacken, where approximately 15000 tufted ducks (Aythya fuligula) were recorded in early February 1996. The
intensity of monitoring was therefore stepped up, with weekly counts being done from
the air instead of the normal monthly counts. Effects from the construction work were
M. Puch . J. Larsen
7.2.3
Monitoring of Fish
The construction work must not block the migration of Rugen herring through the
0resund. When this criteria was set, consideration was also made for a number of other
fish species, such as eel, garfish and lumpsucker, which also use the 0resund as a migration route. The herring which spawn in the western Baltic use the 0resund as their
most important migration route between their summer feeding grounds in the Skagerrak
and their spawning ground. The monitoring carried out has shown that the herring
move into the 0resund from the Kattegat during the early autumn (August-September), with large parts of the breeding stock spending the winter there, mainly in the
deeper areas around Ven. During the spring months there is rapid migration from the
0resund (completed in March) towards the spawning grounds in the western Baltic.
Mter spawning the herring migrate back to the Skagerrak, but the 0resund is not their
only route back.
During the migration seasons of 199511996 and 199611997 a monitoring cruise was
undertaken in the autumn which showed that the herring had migrated into the 0resund
and were present in concentrations which corresponded to what had been seen during
the baseline studies in 1993-1995. Monitoring expeditions during the spring showed
that the herring had left the 0resund for the spawning grounds as expected.
In addition to monitoring cruises this programme also includes continuous logging
of the passage of shoals of herring through Drogden. The equipment for this was adjusted during the spring of 1996 and has been in operation since the beginning of June
1996. Several passages of shoals of herring were recorded during this period.
7.2.4
Monitoring of Birds
A reduction of 15% in the population of breeding eiders (Somateria mollissima) on
Saltholm is acceptable, but no later than 5 years after seabed work is completed the
number of breeding pairs must be at least 90% of the number of breeding pairs counted
during the baseline studies. As far as other breeding waterfowl on Saltholm are concerned, there must not be a significant reduction in numbers. A temporary reduction
in the number of foraging and resting migratory birds on Saltholm as a consequence of
the construction work can be accepted. However, it is expected that the number of birds
will be re-established no more than 2 years after the completion of the construction
work. As far as greylag geese (Anser anser) and mute swans (Cygnus olor) are concerned, it is accepted that there is a risk of a permanent decline in the number of moulting
birds.
As part of the programme, studies have been made of overwintering, breeding and
moulting birds, partly at Saltholm and partly on the Swedish coast between Landskrona
and Falsterbo. Owing to the hard winter of 199511996 and heavy ice formation, including inland waters, the numbers of diving ducks in the 0resund in January and Februarywere large, particularly at the future bridge abutment at Lernacken, where approximately 15000 tufted ducks (Aythya fuligula) were recorded in early February 1996. The
intensity of monitoring was therefore stepped up, with weekly counts being done from
the air instead of the normal monthly counts. Effects from the construction work were