SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

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...

A new eel larva, Leptocephalus pseudomicrocephalus, belonging to the subfamily Bathymyrinae (Anguilliformes, Congridae)

Ano: 1987

URL: http://www.repository.naturalis.nl/record/504262

An eel larva, caught in the mid North Atlantic, represents a new species and is described as Leptocephalus pseudomicrocephalus. In most of its characters it resembles the larvae of the Ariosoma-Bathymyrus group, especially in the pigmentation and the presence of an outer intestine or exterilium. The main differences are the greater length and the number of myomeres.

Saurenchelys halimyon, a new species of nettastomid eel, with comments on Saurenchelys cancrivora Peters, 1864, and a preliminary list of larval and metamorphosed Anguilliformes caught in the mid North Atlantic

Ano: 1988

URL: http://www.repository.naturalis.nl/record/505572

A new species of nettastomid eel, Saurenchelys halimyon, is described and figured. The leptocephalus of Saurenchelys cancrivora Peters, 1864, is redescribed; no resemblance was found to the leptocephalus of Facciolella physonema (Facciola, 1914) as was supposed by Blache (1977). Fourteen species are listed of larval and metamorphosed Anguilliformes caught in April 1980 in the mid North Atlantic.

On the growth of the baleen plate of the Fin Whale and the Blue Whale

Ano: 1983

URL: http://www.repository.naturalis.nl/record/503864

1. In Whales variations in the thickness of the baleen plates are supposed to give an insight into certain cyclical processes in the life of the animal. To a certain extent, by means of these variations, it is possible to reach conclusions about the age of the animal and/or about its recent period of life. In order to get a better insight in the significance of the variations in thickness of the baleen plate, researches are made in the histogenesis of the baleen plate of Fin Whales and Blue Whales, caught in the Antarctic waters. The variations in thickness are caused by variations in thickness of the cortex of the baleen plate. 2. The “root” of the baleen plate consists of the following parts: the corium wall, the epithelium that covers the corium wall,...

Serrivomer beani Gill & Ryder, 1884 (Pisces, Anguilliformes, Serrivomeridae): some aspects of seasonal variation in numbers and distribution in the mid North Atlantic

Ano: 1965

URL: http://www.repository.naturalis.nl/record/504105

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.

Comparison of records of baleen plates and of ear plugs in female Fin Whales, Balaenoptera physalus (Linnaeus, 1758)

Ano: 1987

URL: http://www.repository.naturalis.nl/record/504549

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...

The layered structure of bones of birds as a possible indication of age

Ano: 1969

URL: http://www.repository.naturalis.nl/record/504679

Soest, R.W.M. van; Utrecht, W.L. van.

A method of age determination, new in birds, is described. The method has been derived from similar methods commonly used to determine age of fishes, amphibians, reptilians, and mammals. It consists of demonstrating, by preparation of transverse transparent sections, the presence of annual deposits in the periosteal zone (= zone of outer circumferential lamellae) of bone. Evidence is presented that the layered structures in the periosteal zone are indeed annual and thus related with age.

A remarkable feature in the dentine of teeth of Odontocetes

Ano: 1971

URL: http://www.repository.naturalis.nl/record/504524

The neonatal line in teeth of Phocoena phocoena is studied. The length of the neonatal line measured from the upper end of the cementum to the point where the line ends against that layer, may offer an indication for sex determination in this species.

The existence of different Fin Whale, Balaenoptera physalus, populations in South Atlantic waters. A preliminary study by means of morphological characters

Ano: 1969

URL: http://www.repository.naturalis.nl/record/505141

Beek, J.G. van; Utrecht, W.L. van.

The southern hemisphere has been divided into six Areas for baleen whale management purposes. It was assumed that of the different baleen whale species one population lives in each Area. However, evidence exists which suggests that different Fin Whale populations intermingle on the feeding grounds of an Area. This obviously would have implications with respect to Fin Whale management. Three different types of Fin Whales, distinguished by gunners and the second author of this paper, were visually observed in the South Atlantic catch of Fin Whales. It can be hypothesized that each type represents a different population. During the 1962/63 season on board the Dutch factory ship “Willem Barendsz”, data of mainly the following variables were collected from 53...

The Anatomy and Function of the Ear of the Bottle-nosed Dolphin Tursiops truncatus

Ano: 1984

URL: http://www.repository.naturalis.nl/record/504185

Purves, P.E.; Utrecht, W.L. van.

3. An account is given of sound conductivity experiments which were carried out on the auditory structures in a very fresh, dead specimen of Tursiops. 4. The probable function of the external auditory meatus is discussed in relationship to the arrangement of the accessory air sinuses of the middle ear. 5. The so-called ”auditory scanning” behaviour in odontocete cetaceans is commented upon in the light of preliminary experimental evidence of a vocal sound diffraction pattern.

Age and growth in Phocoena phocoena Linnaeus, 1758 (Cetacea, Odontoceti) from the North Sea

Ano: 1963

URL: http://www.repository.naturalis.nl/record/504731

Data and material are collected from 106 Harbour Porpoises (P. phocoena) from the southern part of the North Sea. All animals are accidentally caught or found stranded. The greatest length for males in the sample is 151 cm, for females 186 cm. For detailed analysis of body measurements, 30 males and 37 females are selected, while from 20 males and 34 females teeth are used for age analysis. The analysis of the body measurements shows sexual dimorphism in the anterior and posterior part of the back, in the flukes and flippers and in the position of the genital slit. The maximum number of dentinal layers found in the teeth is 12. Males attain sexual maturity after the deposition of 5 dentinal layers, females when 6 layers are formed, at a body length of...

Some aspects of the distribution, metamorphosis and growth in Serrivomer parabeani Bertin, 1940 (Pisces, Apodes, Serrivomeridae) related to growth features in their otoliths

Ano: 1978

URL: http://www.repository.naturalis.nl/record/504449

Metamorphosis and growth of Serrivomer parabeani Bertin, 1940, are analysed, in relation to growth features in their otoliths. The animals were caught during the spring expedition in the Mid North Atlantic in 1980. It proved that the actual metamorphosis from leptocephalus to eel-like animal is of short duration. Growth in length and the development of the pigmentation is relatively slow. The animals from this series of samples do not show vertical migration. They are mainly restricted to water layers with temperatures between 8° and 12° C and depths between 450 and 1000 m, except at station 24, at the western side of the Great Meteor Bank, where some animals were caught at depths between 110 and 300 m, during the night.

Notes on eel larvae (Anguilla anguilla Linnaeus, 1758) from the central and eastern North Atlantic and on glass eels from the European continental shelf

Ano: 1982

URL: http://www.repository.naturalis.nl/record/505043

Utrecht, W.L. van; Holleboom, M.A..

Eel larvae caught in the mid North Atlantic and along the continental slope off the Portuguese coast are studied together with samples of glass eels caught just before entering fresh water along the Dutch and French coasts. During their migration from the mid Atlantic towards the continental slope the mean length of the larvae investigated increased from 56 to 66 mm, while the mean diameter of their otoliths increased from 0.17 to 0.23 mm. The animals from the mid Atlantic had three complete growth zones in their otoliths, while the majority of those from the continental slope had four complete growth zones. The specimens from the mid Atlantic show typical larval aspects as e.g. position of the anus and reaction to preservation, this in contrast to most of...

Remarks on the Distribution and Migration of Whales, based on Observations from Netherlands Ships

Ano: 1985

URL: http://www.repository.naturalis.nl/record/504158

Slijper, E.J.; Utrecht, W.L. van; Naaktgeboren, C..

A. GENERAL REMARKS During three years 4500 reports of whales sighted from Netherlands ships were collected, bearing on approximately 11.000 individual animals. Most of the observations were made in the Atlantic and Indian Ocean. It was supposed that the species could be determined with a fairly high degree of reliability in the case of Humpback Whales, Sperm Whales and Right Whales. No distinction could be made between Blue, Fin, Sei and Bryde Whales. They were collected under the heading Rorquals. Catches of land stations and strandings of whales, however, indicate that in all areas, at least a part of these Rorquals must have been Blue or Fin Whales. Probably the majority of this part were Fin Whales. Nevertheless it must he emphasized that the...

Comparison of accumulation patterns in layered dentinal tissue of some Odontoceti and corresponding patterns in baleen plates and ear plugs of Balaenopteridae

Ano: 1964

URL: http://www.repository.naturalis.nl/record/503965

The data of the present examination show that the teeth of delphinids reach their ultimate diameter before eruption from the gum. However, growth in length continues during the first three or four years after birth, thereafter the increase in length is neglegible. In the same period the width of the dentinal growth layers decreases rapidly to approach an asymptote when about 10 layers are deposited. In Phocoena phocoena and Delphinus delphis the greatest thickness of the first dentinal layer is about 350 μm and never exceeds this figure. The decrease in width of the layers can only be expressed by a straight line in a logarithmic plot. Due to this decrease the layers are not comparable to each other. Secondary layers can only be seen in the first three or...

Growth in larval and metamorphosed Eurypharynx pelecanoides Vaillant, 1882 (Pisces, Anguilliformes, Eurypharyngidae) from the mid North Atlantic

Ano: 1981

URL: http://www.repository.naturalis.nl/record/505057

The difference between the larvae of Eurypharynx pelecanoides and Saccopharynx ampullaceus, both belonging to the suborder Saccopharyngoidei (formerly Lyomeri), does not consist only of different numbers in myomeres but also of the structure of the suspensorium of the lower jaw. In E. pelecanoides it consists of two separate bones, the hyomandibulare and the quadratum. According to Orton (1963) in S. ampullaceus the suspensorium consists of only one piece of bone. In the larvae of E. pelecanoides there is no upper jaw or related structure present, up to a length of about 20 mm. In the larvae as well as in the metamorphosed specimens of E. pelecanoides, growth in length of the bony components of the skull, forming the upper and lower jaw and its...