| Species | Number of breeding pairs[80] | |
|---|---|---|
| Great Britain and Ireland | Norway | |
| Fulmarus glacialis | 306,000 | 1,100 |
| Puffinus puffinus | > 175,000 | — |
| Hydrobates pelagicus | 105 or 106 | 103 or 104 |
| Oceanodroma leucorrhoa | 104 | 102 |
| Sula bassana | 138,000 | 760 |
| Phalacrocorax carbo | 8,100 | 12,000 |
| P. aristotelis | 31,000 | 33,000 |
| Stercorarius skua | 3,100 | 1[81] |
| S. parasiticus | 1,100 | 8,000 |
| Larus ridibundus | 74,000 | 4,000[82] |
| L. canus | 12,000 | (150,000)[82] |
| L. fuscus | 47,000 | 9,000[82] |
| L. argentatus | 333,000 | (260,000)[82] |
| L. marinus | 22,000 | (40,000)[82] |
| Rissa tridactyla | 470,000 | 510,000 |
| Sterna sandvicensis | 12,000 | — |
| S. dougalli | 2,300 | — |
| S. hirundo | 14,000 | (13,000)[82] |
| S. paradisaea | (31,000) | (21,000)[82] |
| S. albifrons | 1,800 | — |
| Alca torda | (144,000) | 30,000 |
| Uria aalge | (577,000) | 100,000 |
| U. lomvia | — | 1,000 |
| Cepphus grylle | 8,300 | 22,000 |
| Fratercula arctica | (490,000) | 1,250,000 |
| Total | ca. 3,000,000 | ca. 2,500,000 |
Use of fishing gear close inshore, especially pound nets set near colonies of diving seabirds, can take a heavy toll under special weather conditions. In 1969 at Runde, 85 birds, mainly auks, shags, and some diving ducks, were caught in one net in 24 hours; this is an exceptionally high figure. The total loss of diving seabirds in pound nets per year in Norway (about 6,000 nets fishing for 40 days) was estimated to be at least 40,000 birds in 1969. The data are too unreliable to give species composition, however, since fishermen rarely make note of this.
Amounts of fish offal from offshore trawlers, drift-netters, and longline fishing boats have increased in recent years, and some seabirds, particularly kittiwakes, fulmars, and gannets make use of this new and readily available food source. Thus, although the use of fishing gear is a serious threat to seabird survival, fish waste from the same boats provides an abundant food supply for the more pelagic species.
Pollution
No quantitative investigation similar to those made in Great Britain, Netherlands, and Belgium (Tanis and Bruyns 1968) has been carried out on the impact of oil pollution on seabirds in Norway. The northern Norwegian population of the most threatened species, murres and razorbills, winter in North Sea coastal areas where oil pollution and oiled birds have most frequently been found. It is possible that whole populations winter every year in the same area, and if they happen to be in a heavily polluted area, a particular population may be seriously affected. Such an occurrence is believed to have caused the dramatic decline in the Sør Fugløy population (cf. Table 5).
Although not yet serious, pollution by persistent toxic chemicals such as organochlorines and mercury is a problem even in northern Norway, because the northbound coastal current brings water masses, plankton, and nekton from areas with industrial wastes. Analysis of the eggs of herring gull (Larus argentatus), murre, razorbill, and kittiwake in 1972 showed relatively low levels of mercury; the only species with a relatively high level of mercury (mean 0.58 ppm) was the gannet (Fimreite et al. 1974). This elevated toxic burden may have caused a reduced breeding success for the gannet. Analysis of concentrations of PCB's and DDT/DDE showed that the levels of these organochlorines were generally also lower in Norwegian seabirds than in those of Britain (Fimreite et al. 1977).
Protection and Necessary Conservation Measures
Total protection of some of the important seabird colonies (including the surrounding nearshore waters) has proven very effective, especially when the protection is so strict that landing is prohibited for a specified period during incubation and fledging. However, to reduce the rapid decrease of some species, a total hunting prohibition of those species must be instigated, oil pollution must be reduced, and the fisheries must be regulated to reduce the mortality caused by fishing gear.