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| Utrecht, W.L. van; Utrecht-Cock, C.N. van; Graaf, A.M.J. de. |
| In the mid North Atlantic Chauliodus sloani is caught mainly between 55° and 29° N, while the majority is caught north of 35° N. The greatest density is found around 40° N. Chauliodus danae has the northern limit of its distribution at about 45° N. C. danae, in particular the smaller specimens, shows clear vertical migration and has food preference, while C. sloani does not show such migration and is most probably a random feeder. In both species there is a significant increase in length from south to north. From the analysis of growth features in the otoliths it is demonstrated that C. danae grows relatively faster than C. sloani, though it reaches a smaller maximum length. C. sloani attains a greater maximum length and a higher age. Together with some... |
| Tipo: Article / Letter to the editor |
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| Ano: 1987 |
URL: http://www.repository.naturalis.nl/record/504262 |
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| Utrecht, W.L. van; Utrecht-Cock, C.N. van. |
| In Rectangular Midwater Trawl samples taken along the 30°W meridian in the mid North Atlantic, Serrivomer beani reaches its greatest density in April-June between 25° and 34°N. In this period the larvae of this species are caught here as well. There is a significant increase in size of the individuals from 24° to 55°N. In October samples along the same meridian, S. beani was caught from 24° to 40°N only. Because the net used is not effective in collecting size classes above about 300 mm, it is presumed that north of 40°N S. beani is present, but consists of larger individuals. No evidence is found that S. beani undertakes diurnal vertical migration. |
| Tipo: Article / Letter to the editor |
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| Ano: 1987 |
URL: http://www.repository.naturalis.nl/record/504549 |
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| Utrecht, W.L. van; Utrecht-Cock, C.N. van. |
| 1. From 54 female fin whales chosen at random from a greater number of animals from which data and material were collected during the Antarctic whaling season 1962/1963, records have been made of the baleen plates and the ear plugs. For the records the complete baleen plates including the part of the plates embedded in the gum are used. All ear plugs used for this study were complete and undamaged. 2. According to their ovaries and baleen records 50 animals were sexually mature, 4 animals were sexually immature. 3. In each individual the record of the complete baleen plate is entirely comparable to the record of the ear plug, in its general trend and in the sequence of peaks and hollows. Also the regular cyclic repetition found in the records of the baleen... |
| Tipo: Article / Letter to the editor |
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| Ano: 1969 |
URL: http://www.repository.naturalis.nl/record/504679 |
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| Utrecht-Cock, C.N. van. |
| 1. From Antarctic female Fin Whales, Balaenoptera physalus, a collection, consisting of baleen plates and the parts of these plates embedded in the gum, ovaries, and a number of earplugs was examined, in order to determine the age of these animals and to get a better insight in some characteristics of their reproduction. Data concerning pregnancy and lactation were also recorded. The material was sampled from animals worked up on board the f.f. “Willem Barendsz” during the Antarctic seasons 1953/1954 to 1959/1960 inclusive. The possibilities and values of age determination for this species were considered, based on the results of the analyses of the above material. 2. In most seasons the length distribution of the female Fin Whales, from which the material... |
| Tipo: Article / Letter to the editor |
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| Ano: 1965 |
URL: http://www.repository.naturalis.nl/record/504146 |
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