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Article Reference Growth changes in plaice, cod, haddock and saithe in the North Sea: a comparison of (post-)medieval and present-day growth rates based on otolith measurements
Fishing effort has strongly increased in the North Sea since the mid-19th century, causing a substantial reduction in the population size of exploited fish stocks. As fisheries research has developed simultaneously with the industrialisation of the fisheries, our knowledge of population dynamics at low levels of exploitations is limited. Otoliths retrieved from archaeological excavations offer a unique opportunity to study growth rates in the past. This study compares historical and present-day growth rates for four commercially important demersal fish species. A total of 2532 modern otoliths (AD 1984–1999) and 1286 historical otoliths (AD 1200–1925) obtained from archaeological excavations in Belgium and Scotland were analysed. Comparison of the growth patterns between eras revealed a major increase in growth rate of haddock, whereas growth changes were not observed in saithe and only in the smaller size classes of plaice and cod. Comparison of our results with literature data indicates that the observed growth rate changes in plaice and cod occurred within the 20th century. Apparently the onset of industrialised fisheries has not greatly affected the growth of plaice, cod and saithe populations in the North Sea. This result contradicts the expectation of density-dependent limitation of growth during the era of pre-industrialised fishing, but is in agreement with the concentration hypothesis of Beverton (Neth. J. Sea Res. 34 (1995) 1) stating that species which concentrate spatially into nursery grounds during their early life-history may ‘saturate’ the carrying capacity of the juvenile habitat even though the adult part of the population is not limited by the adult habitat.
Located in Library / RBINS Staff Publications
Article Reference Seasonality only works in certain parts of the year: The reconstruction of fishing seasons through otolith analysis
Seasonality estimations using incremental data usually suffer from small sample sizes and from the lack of comparison with sufficiently large modern samples. The present contribution reports on incremental studies carried out on large assemblages of plaice (Pleuronectes platessa) and haddock (Melanogrammus aeglefinus) from a late medieval fishing village (Raversijde, Belgium) on the North Sea coast. In an attempt to refine previous seasonality estimates made for this site, and to expand conclusions concerning general methodology, extensive monthly samples of modern otoliths of these species, caught within the North Sea, have also been investigated. The modern material shows that the timing of the seasonal changes in the edge type (hyaline or opaque) of the otoliths is extremely variable and that it is dependent on the fishing ground, the year considered, and the age of the fish. It also appears that the increase of the marginal increment thickness is highly variable, to such an extent that the thickness of the last increment of a single otolith is mostly useless for seasonality estimation. Where large archaeological otolith assemblages can be studied, preferably from single depositional events, seasonality determination becomes possible on the condition, however, that the archaeological assemblage corresponds to fish that were captured during their period of fast growth. The growth ring study on the otoliths from Raversijde shows that plaice fishing took place in spring and that it was preceded by a haddock fishing season, probably in late winter/early spring.
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Article Reference Ancient breeds of domestic fowl (Gallus gallus f. domestica) distinguished on the basis of traditional observations combined with mixture analysis
Using a large assemblage of domestic fowl bones from a classical site, a methodology is presented that allows the recognition of breeds. The approach differs from previous research in which tarsometatarsi were used exclusively. In the present paper, frequency histograms of long bone lengths and mixture analysis were combined with observations on medullary bone development. By concentrating on the analysis of bones with medullary bone, only the securely sexed part of the population (the females) is considered, thereby avoiding problems related to the use of spur development in tarsometatarsi. Three breeds of different sizes could be recognized, of which the smallest shows a high incidence of spurred females.
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Article Reference Fish remains from three Upper Palaeolithic cave deposits in southern Belgium
Fish remains are described that were excavated in the 19th century from Trou de Chaleux, Trou du Frontal and Trou du Sureau, three Upper Palaeolithic cave sites in the Meuse basin, Belgium. After a critical assessment of possible taphonomic agents acting in caves, it is concluded that the material — consisting mainly of medium-sized and large salmonids, burbot and cyprinids — is anthropogenic. Using present-day behavioural information on the identified fish species it is hypothesised that the exploited fish were an abundant and predictable food resource during the spawning season, when they occurred en masse in shallow, marginal waters. Finally the possible fishing techniques and the dietary role of freshwater fish in Palaeolithic times are discussed.
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Article Reference The distinction of isolated bones from plaice (Pleuronectes platessa), flounder (Platichthys flesus) and dab (Limanda limanda): a description of the diagnostic characters
The osteology of 38 skeletal elements is investigated in plaice, dextral and sinistral flounder, and dab with the aim of defining diagnostic characters that allow species identification of isolated bones from archaeological excavations. Five of these 38 skeletal elements have been mentioned in the literature as being diagnostic, but they appear to be unreliable for identification. All other elements allow identification, although only 23 permit the recognition of all three species. The individual bone elements and their diagnostic criteria are depicted and described in detail. Attention is paid to individual variation, and, when relevant, size-related morphological changes are also described. The keys that are developed for the various elements are finally tested on a large flatfish bone assemblage from an archaeological site. On the basis of these results, the success rate of the identifications for the various bones is discussed. Possible strategies for identification work on this group are suggested that take into account the extent of the reference collection, the time spent on the identifications and the experience needed in comparative osteology of these flatfish.
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Article Reference Body length estimation of the European eel Anguilla anguilla on the basis of isolated skeletal elements
Using a large series of dry skeletons of modern European eel Anguilla anguilla (Linnaeus, 1758) from Belgium and the Netherlands, the relationship between fish length and individual bone measurements is investigated. The aim of the study is to provide adequate regression equations between both parameters. This methodology is relevant for both palaeoecological and ecological researches since isolated skeletal elements survive in large numbers on archaeological sites and in the stomach contents, faeces or regurgitations of piscivorous animals. The predictive value for the length estimations is explored for various skeletal elements and the accuracy of the obtained regression formulae is compared to that of the formulae already existing in literature. Particular attention is paid to the use of vertebrae, taking into account that different morphotypes can be distinguished amongst them.
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Article Reference Description of Muricopsis (Muricopsis) gorii (Gastropoda: Muricidae: Muricopsinae) from southern São Tomé.
A new species of Muricopsis is described from Sete Pedras Island, São Tomé. It is compared with Muricopsis matildeae Rolán & Fernandes, 1991.
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Article Reference The genus Pradoxa Fernandes & Rolán, 1993 (Gastropoda: Muricidae) in SãoTomé, Príncipe and Annobón.
The genus Pradoxa is revised and all the species are described, compared and illustrated. Two new species are described from São Tomé, Pradoxa gorii spec. nov. and P. urdambideli spec. nov. The radula is illustrated for P. confirmata (Fernandes & Rolán, 1990), P. thomensis (Fernandes & Rolán, 1990) and P. gorii spec. nov. The subfamilial classification is discussed and a comparative table is added in the appendix.
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Inproceedings Reference Utilisation des propriétés antigéniques du collagène dans la détermination taxonomique de l'os
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Inproceedings Reference Antigenic properties of Type I collagen and Taxonomy
Located in Library / RBINS Staff Publications