12 research outputs found
A comparison of variability and bias when ageing Northeastern Atlantic minke whales (Balaenoptera acutorostrata) by counting growth layer groups in the mandible and bulla tympanica
The age of 43 minke whales (Balaenoptera acutorostrata) was estimated by counting growth layer groups (GLGs) GLGs in 500um thick haemotoxylin stained transverse sections of left and right mandible. The same whales were also aged by counting GLGs in 150um unstained sections of left and right bulla tympanica. The staining and preparation methods were also used to prepare and stain mandible sections of a sperm whale and the GLG count of this was the same as the GLG count of a longitudinal section of a tooth from the same animal. Minke whale mandible age estimates had higher CV (63% on average) than the bulla age estimates (36% on average). Comparing the age estimates with the number of ovulations revealed that both methods underestimated the true age of the whales
Seal investigations in the North Atlantic in 1974
Accounts are given of weather and ice conditions, the distribution of seals and of sampling of harp and hooded seals at Newfoundland-Labrador, in the West Ice (at Jan Mayen), in the East Ice (in the Eastern Barents Sea) and in the Denmark trait. A few provisional results of age analysis are given. Some observations from the coast of Norway suggest increasing numbers of local common and grey seals
Seal investigations in the North Atlantic in 1974
Accounts are given of weather and ice conditions, the distribution of seals and of sampling of harp and hooded seals at Newfoundland-Labrador, in the West Ice (at Jan Mayen), in
the East Ice (in the Eastern Barents Sea) and in the Denmark
Strait. A few provisional results of age analysis are given. Some
observations from the coast of Norway suggest increasing numbers
of local common and grey seals
Seal investigations in the North Atlantic in 1972
Accounts are given of field work at Newfoundland—Labrador, in the Jan Mayen area of the Greenland Sea (West Ice),
in the southeastern Barents Sea (East Ice) and in the Denmark Strait to collect material and data for studies of harp and hooded seals. The distributions of seals and ice are shown on maps
Investigations of common seals (Phoca vitulina) and grey seals (Halichoerus grypus) in Rogaland and Finnmark counties Norway, in 1981
The outer coastline from Bømlafjorden to Jæren and Lysefjorden in
Rogaland were surveyed 29 May-5 June. Another survey was carried
out on the coast of Finnmark from Varangerfjorden to Sørøya 26
June-7 July 1981.
In Rogaland a total of 75 common seals was recorded. The seals
were most abundant in the Kvitsøy-Håsteinen area (38 seals) and in
Lysefjorden (27 seals). In Kongsfjorden, Finnmark, 23 pups were
observed (corresponding to a total stock in excess of 100 seals).
Another colony of common seals was found at Sørøya (20 seals), and
common seals were also seen in Varangerfjorden, Tanafjorden and
Kobbfjorden.
Concentrations of grey seals were found in the Espevær-Utsira area
(36 seals) and at Kjør (60 seals) in Rogaland, and in Syltefjorden
(40 seals) and at Sørøya (70 seals) in Finnmark. Scattered seals
or small groups were also seen outside these areas.
Due to adverse weather conditions very few common seals were
observed during the surveys, and the numbers recorded probably are
significantly lower than actual stocks. So far, the available data
are insufficient to assess the stocks of common seals in Rogaland
and Finnmark. However, the observations of grey seals indicate an
increase from assessed stocks in the early 1960-ies.
Stomachs from a total of ten common seals and nine grey seals were
examined during the surveys. Haddock, sand eels and flatfishes
were identified in the common seals, while the grey seal stomachs
contained catfish, saithe, haddock, herring, lumpsucker, sand eels
and flatfishes. The maximum volume of stomach contents found in a
common sea1 was 4 1, and volumes up to 6 l were recorded in grey
seals.
The average infestation of parasitic nematodes in the stomachs of
examined common seals was 64 worms, while the average infestation
in the grey seals was 492 worms.
An aerial survey to count whitecoated grey seal pups was carried
out 7 November in Rogaland. No pup or concentration of grey seals
was observed, and if grey seals do produce pups in Rogaland,
pupping probably occurs in early Octoher.
Aerial surveys were also carried out along the coast of Finnmark
28 and 29 October. No grey seal pup was found, and the surveys
were repeated 17-20 November. At that time concentrations of grey
seals were ohserved on shore at the presumed breeding localities.
It therefore seems likely that pupping in Finnmark occurs later
than 20 November
Selundersøkelser i det nordlige Atlanterhav i 1974
Accounts are given of weather and ice conditions, the distribution of seals and of sampling of harp and hooded seals at Newfoundland-Labrador, in the West Ice (at Jan Mayen), in the East Ice (in the Eastern Barents Sea) and in the Denmark trait. A few provisional results of age analysis are given. Some observations from the coast of Norway suggest increasing numbers of local common and grey seals
Seal investigations in the North Atlantic in 1973
Accounts are given of weather and ice conditions, the distribution of seals and sampling of harp and hooded seals at New
foundland-Labrador and in the Jan Mayen area of the Greenland Sea through the sealing season in March—April. Information on harp seals and sealing in the southeastern Barents Sea has been compiled from journals kept by four sealing vessels, Bearded seals were studied in the waters of Svalbard in July— August. On this expedition some 350 walruses were recorded and a local population of common seals was sampled for identification
Selundersøkelser i det nordlige Atlanterhav i 1973
Accounts are given of weather and ice conditions, the distribution of seals and sampling of harp and hooded seals at New
foundland-Labrador and in the Jan Mayen area of the Greenland Sea through the sealing season in March—April. Information on harp seals and sealing in the southeastern Barents Sea has been compiled from journals kept by four sealing vessels, Bearded seals were studied in the waters of Svalbard in July— August. On this expedition some 350 walruses were recorded and a local population of common seals was sampled for identification