| IBA |
Portnova Islands
Louisbourg, Nova Scotia |
| Site Summary |
| NS006 |
Latitude
Longitude |
45.941° N
59.790° W |
Elevation
Size |
0 - 10 m
4.78 km² |
Habitats:
open sea, inlets/coastal features (marine), coastal cliffs/rocky shores (marine)
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Land Use:
Fisheries/aquaculture
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Potential or ongoing Threats:
Disturbance, Hunting
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| IBA Criteria: Globally Significant: Congregatory Species |
| Conservation status: |
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Site Description
Portnova Island is located about 13 km southeast of the town of Louisbourg, which is on the eastern coast of Cape Breton Island, Nova Scotia. The IBA also includes Chameau Rock, which is smaller and just a few kilometres north of Portnova, roughly midway to Cape Breton (the actual cape). This collection of islands, islets and reefs is rocky and treeless. They are ice-bound only in the spring when onshore winds blow ice flows in from the Gulf of St. Lawrence. These islands and islets experience typical damp and foggy Maritime weather with snow rarely lying on the ground for long. The tidal range is approximately 3 - 4 m.
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Birds
The majority (> 70%) of the North American population of Great Cormorants is found in Nova Scotia. The most recent estimates suggest that there are a little over 6,000 birds in Canada, making the colony on Portnova Island (approximately 2.5% the North American population) highly significant. The results of earlier studies indicate that there were as many as 507 birds in 1971, but in 1992, there were only 310 on Portnova Island. Although Great Cormorants often breed inland in Europe and Asia, they are strictly coastal breeders in North America. Cormorants prefer nest sites that are within commuting range of adequate food resources and safe from terrestrial predators. As a result, isolated islands, and steep rocky cliffs that are within commuting range of adequate food resources, are favoured as nesting sites.
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IBA Criteria |
| Species↓ T | A | I |
Links |
Date |
Season |
Number |
G |
C |
N |
| Great Cormorant |
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1971 - 1992 |
SU |
310 - 507 |
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✔ |
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Note: species shown in bold indicate that the maximum number exceeds at least one of the IBA thresholds (sub-regional, regional or global). The site may still not qualify for that level of IBA if the maximum number reflects an exceptional or historical occurrence.
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Conservation Issues
The remoteness of Portnova Island, and the rough waters of the surrounding sea, make it very difficult for landing boats. As a result, the island receives only a few visitors and so the Great Cormorant colony is relatively undisturbed. However, the difficulties in accessing the island also prevent biologists from surveying the colony frequently.
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