Jaas PAPER Carbon and Nitrogen Stable Isotope Ratio Analysis of Freshwater, Brackish and Marine ﬁsh from Belgian Archaeological Sites (1St and 2Nd Millennium AD)†

View Article Online / Journal Homepage / Table of Contents for this issue JAAS Dynamic Article LinksC<

Cite this: J. Anal. At. Spectrom., 2012, 27, 807 www.rsc.org/jaas PAPER Carbon and nitrogen stable isotope ratio analysis of freshwater, brackish and marine ﬁsh from Belgian archaeological sites (1st and 2nd millennium AD)†

Benjamin T. Fuller,*ab Gundula Muldner,€ c Wim Van Neer,ad Anton Ervyncke and Michael P. Richardsbf

Received 12th December 2011, Accepted 12th March 2012 DOI: 10.1039/c2ja10366d

Carbon and nitrogen stable isotope ratios were measured in 157 fish bone collagen samples from 15 different archaeological sites in Belgium which ranged in ages from the 3rd to the 18th c. AD. Due to diagenetic contamination of the burial environment, only 63 specimens produced results with suitable C : N ratios (2.9–3.6). The selected bones encompass a wide spectrum of freshwater, brackish, and marine taxa (N ¼ 18), and this is reflected in the d13C results (28.2& to 12.9%). The freshwater fish have d13C values that range from 28.2& to 20.2&, while the marine fish cluster between 15.4& and 13.0&. Eel, a catadromous species (mostly living in freshwater but migrating into the sea to spawn), plots between 24.1& and 17.7&, and the anadromous fish (living in marine environments but migrating into freshwater to spawn) show a mix of freshwater and marine isotopic signatures. The d15N results also have a large range (7.2& to 16.7&) indicating that these fish were feeding at many different trophic levels in these diverse aquatic environments. The aim of this research is the isotopic characterization of archaeological fish species (ecology, trophic level, migration patterns) and to determine intra-species variation within and between fish populations differing in time and location. Due to the previous lack of archaeological fish isotope data from Northern Europe and Belgium in particular, these results serve as an important ecological backdrop for the future isotopic reconstruction of the diet of human populations dating from the historical period (1st and 2nd millennium AD), where there is zooarchaeological and historical evidence for an increased consumption of marine fish. Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. Introduction from the same or related sites, in terms of location and time period. Most often, the food products measured comprise the d13 Measurement of the stable isotope ratios of carbon ( C) and bones of wild and domestic animals.5–9 However, the isotopic d15 nitrogen ( N) in bone collagen has increasingly become an analyses of fish remains are reported much less frequently. This important method to determine the general types of dietary 1–4 can be linked to the fact that fish skeletal material is often poorly patterns in archaeological human populations. The vast preserved, compared to that from other animals, and to the fact majority of this research has focused on the reconstruction of that the adequate recovery of fish bones at an archaeological site past subsistence patterns by comparing the stable isotope ratios requires sieving, which often was not routinely used on excava- from human bone collagen to those of consumption remains tions until the last decades.10 This is unfortunate as the isotopic analysis of fish remains can provide a more refined picture of the dietary habits of former humans.11–14 Research on fish is espe- a Laboratory of Biodiversity and Evolutionary Genomics, Centre for cially important for isotopic studies of European human pop- Archaeological Sciences, University of Leuven, Ch. Deberiotstraat 32, st nd B-3000 Leuven, Belgium. E-mail: [email protected] ulations dating from the historical period (1 and 2 millennium bDepartment of Human Evolution, Max Planck Institute for Evolutionary AD) where there is evidence for an increased consumption of Anthropology, Deutscher Platz 6, D-04103 Leipzig, Germany marine fish in the diet.15–19 c Department of Archaeology, University of Reading, Whiteknights P.O. In this study, stable isotope ratios of carbon and nitrogen were Box 227, Reading RG6 6AD, UK dRoyal Belgian Institute of Natural Sciences, Vautierstraat 29, B-1000 measured from archaeological freshwater, brackish and marine Brussels, Belgium fish recovered at archaeological sites in Belgium (Fig. 1). The eFlanders Heritage, Koning Albert II-laan 19, box 5, B-1210 Brussels, selected bones encompass a wide spectrum of species that are Belgium regularly found during excavations and that were thus of f Department of Anthropology, University of British Columbia, Vancouver, importance for past human subsistence. The freshwater taxa British Columbia V6T 1Z1, Canada † Electronic supplementary information (ESI) available. See DOI: likely represent fish that were locally captured, and the marine 10.1039/c2ja10366d fish from the inland sites are to be considered imports. The focus

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 807 View Article Online

Fig. 1 Map of Belgium with the main river basins and the sites sampled in this study (1: Antwerpen, 2: Dendermonde, 3: Ename, 4: Gent, 5: Ieper, 6: Londerzeel, 7: Mechelen, 8: Raversijde, 9: Tongeren, 10: Tournai).

of this research is the assessment of the species’ isotopic char- stable isotope ratios are used to determine the trophic level or the acteristics (determined by their ecology, place in the foodchain, type of protein in the diet of an organism.1–4 With each stepwise etc.) and of intra-species variation (both within populations and increase in the food chain, d15N values increase by 3–5& relative between populations differing in time and/or location). This will to the diet21,22 and a recent literature review23 has placed this

Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. lead to a better understanding of the aquatic isotopic ecology value at 3.6 1.3&. This phenomenon is known as the ‘trophic during the historical period in Belgium. In this way, the isotopic level effect’, and due to the large number of steps in aquatic food results of this study will be of great value for the more accurate chains, d15N values can become very elevated in higher trophic determination of human diets during historical times in north- level fish, or in birds and mammals consuming aquatic western Europe, which is an area of active research. resources.24 However, for a more detailed discussion of the complexities and uncertainties associated with nitrogen isotope Stable isotope ratios and diet ratios and how they can be used as trophic discrimination factors see ref. 25–27. Carbon and nitrogen stable isotope compositions are measured In aquatic ecosystems d13C and d15N measurements can also be as the ratios of the heavier isotope to the lighter isotopes (13C/12C used to determine the origin of species inhabiting freshwater, or 15N/14N) and are reported in standard delta (d) notation as brackish, and marine environments.17,28 The two most important parts per thousand (per mil, &) relative to internationally primary producers in marine ecosystems are microalgae defined standards for carbon (Vienna Pee Dee Belemnite, VPDB) (phytoplankton) and macroalgae (kelps and seaweeds) and these and nitrogen (Ambient Inhalable Reservoir, AIR).1 Bone are isotopically distinct. Phytoplankton have higher d13C values collagen is the most abundant protein in skeletal remains and it is compared to kelps and seaweeds,29 and the contribution of kelp- routinely analyzed for its carbon (d13C) and nitrogen (d15N) derived carbon to nearshore detrital foodwebs can be consider- stable isotope ratios, since it is usually all that remains of the able in marine ecosystems and has a significant impact on organic tissues of an organism after burial.3,4 The stable isotope consumer d13C values.30–32 As a result, organisms living in near- ratios reflect the protein portion of the averaged diet of an shore and benthic environments generally have 13C- and 15N- organism during the period of bone growth.20 In terrestrial enriched results compared to species living in offshore and environments, carbon stable isotope ratios are useful to distin- pelagic environments.29,33 The isotopic composition of marine 34–36 guish between C3 (most vegetables, fruits, nuts, wheat, and species also varies with respect to latitude. This is again due barley) and C4 (esp. sugarcane, sorghum, maize and millet) to the isotopic values of the primary producers, with species from plants or animals/humans consuming these plants.1–4 Nitrogen higher latitudes having lower d15N values compared to species

808 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012 View Article Online

from the middle latitudes that display elevated d15N values.36 The sampling procedure for the recovery of the fish bone involves wet analysis of stable isotope ratios in aquatic environments is sieving of sediment over a series of sieves of 4, 2 and 1 mm mesh complex and for detailed reviews see ref. 10,17,23 and 37. size, which ensures the recovery of even the smallest fish remains. Identification of the fish bones was carried out by comparison to

st the extensive modern reference collection housed at the Royal Importance of fish in the human diet: the case of 1 and Belgian Institute of Natural Sciences. The taxonomy was recor- nd 2 millennium Belgium ded and when the bone was sufficiently well preserved, the cor- On the territory of what is now Belgium, human dietary patterns responding fish length was also established. This was done by have undergone a marked evolution during the historical period direct comparison with modern fish skeletons of known body (i.e. the first two millennia AD). A diachronic comparison of length. The reconstructed fish lengths are expressed as centi- archaeozoological assemblages of a large number of sites shows metres standard length (cm SL), i.e. the distance from the tip of a marked shift from a diet in which fish played only a minor role the snout to the base of the tail (Table S1†). (Roman period; 1st to 5th c. AD), to a diet in which freshwater A total of 157 archaeological fish remains from 15 Belgian species were frequently incorporated (middle ages: 6th to 10th c. archaeological sites were selected for stable isotope ratio analysis AD), and finally a food procurement pattern in which the place (Fig. 1 and Table 1). The selected bones encompass a wide ¼ of freshwater fish is gradually taken over by marine species spectrum of freshwater, brackish and marine taxa (N 18), (middle ages and postmedieval period: 11th to 18th c. AD). Within selected for their variety in ecology (both habitat choice and the latter period, initially marine species low on the food chain place in the food chain). They include four species from the are the most abundant but gradually predatory marine fish gain Cyprinidae family: roach (Rutilus rutilus), ide (Leuciscus idus), more importance in the diet.38–40 The timing of the intensification tench (Tinca tinca) and carp (Cyprinus carpio f. domestica). of marine exploitation and the decline of freshwater fishing Other freshwater taxa sampled are pike (Esox lucius) and differs geographically within northwestern Europe.19,41 More- whitefish (Coregonus sp.). A single catadromous fish is present in over, in different regions different species are involved while the sample set, eel (Anguilla anguilla), while three other taxa trends in their exploitation do not necessarily follow the same investigated are anadromous: smelt (Osmerus eperlanus), stur- patterns. Additionally, it has been demonstrated that within geon (Acipenser sp.) and shad (Alosa sp.). The marine environ- a species isotopic signals differ depending on geographical ment is represented by eight taxa, of which four belong to the distribution (e.g. for cod, see ref. 19) while diachronic shifts Pleuronectidae (a flatfish family): plaice (Pleuronectes platessa), cannot be excluded either (e.g. through the eutrophication of flounder (Platichthys flesus), halibut (Hippoglossus hippoglossus) biotopes or climatic shifts). In order to obtain valid reference and unidentified Pleuronectidae. Halibut bones are very diag- data for human dietary studies, it is therefore necessary to nostic, but it is often difficult to distinguish plaice, flounder and 43 analyze the isotope ratios of fish consumed per region, per time dab (Limanda limanda) from isolated bone elements. These period. unknown specimens have also been analysed and are termed The marine fish that are typically found on Belgian inland sites ‘flatfish’ here. The remaining four marine taxa are herring from historical times essentially comprise three groups: herring (Clupea harengus), and three gadids: haddock (Melanogrammus (Clupea harengus), members of the cod family, mainly cod (Gadus aeglefinus), whiting (Merlangius merlangus) and cod (Gadus Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. morhua), haddock (Melanogrammus aeglefinus) and whiting morhua). Relevant ecological and zoogeographic information (Merlangius merlangus), and flatfish, mainly plaice (Pleuronectes about these taxa will be presented, within a Belgian context, platessa), flounder (Platichthys flesus) and more rarely dab when the stable isotope results are interpreted per taxon (see (Limanda limanda). The continental fish are mainly eel (Anguilla Discussion). Finally, it should be mentioned that a single spec- anguilla), cyprinids (Cyprinidae, with as major species roach imen of anchovy (Engraulis encrasicolus) was tested but this (Rutilus rutilus), bream (Abramis brama), gudgeon (Gobio gobio) yielded no results. From three freshwater species, pike (Esox and, from the 13th c. onwards, domestic carp (Cyprinus carpio lucius), roach (Rutilus rutilus), and eel (Anguilla anguilla), enough f. domestica)). On top of the diachronic trends explained above, material was sampled to attempt a comparison between pop- the frequencies of these species can vary considerably between ulations. The pike and eel were selected because they represent sites and contexts (depending on their purchasing power, status, high trophic level feeders whereas the roach was chosen because ideological background, the impact of historical events influ- it is a low trophic level feeder. For marine fish, comparisons encing their availability on the markets, etc.). Without doubt, it between populations were not yet attempted because, compared must be envisaged that both the large overall dietary trends and to freshwater species, there is much more uncertainty about the the more punctual dietary variations have had an impact upon provenance (catching grounds) of the specimens (which shift 38 the isotopic composition of the skeletal material of people who through time). inhabited or used these sites. Contexts and sites sampled Material and methods The specimens selected derive from a number of sites spanning a range of ages (3rd–18th c. AD). For the present study, only Collection and identification procedures of the fish samples specimens derived from archaeological contexts characterized by Since the early 1990’s fish remains have been systematically good preservation conditions and a secure dating horizon were excavated and studied at archaeological sites in Belgium (in analyzed. As always in archaeology, the latter does not mean that particular in Flanders, the northern part of the country).42 The all assemblages can be linked to a narrow time period, but it

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 809 View Article Online

Table 1 Information about the archaeological sites, depositional contexts, chronology, and references for the ﬁsh bones sampled in this study (for the dates, A stands for ‘ﬁrst half of’, B for ‘second half of’)

Site Depositional context Dating (c. AD) References (site) References (ﬁshbone analysis)

Antwerpen Koolkaai Cesspit 17 68 69 Dendermonde De Cop Cesspit 14–15 70 Van Neer and Ervynck unpubl. Ename portus Refuse layer 11 71 Van Neer and Ervynck unpubl. Ename abbey kitchen Refuse layer below wooden ﬂoor 15B–16A 71 72 Ename abbey priory Cesspit 17 71 73 Gent Belfortstraat Refuse layer 12A 74 75 Gent portus Refuse layer 10B–12 76 Van Neer and Ervynck unpubl. Ieper Verdronken Weiden Refuse context 13B–14A 77 Van Neer and Ervynck unpubl. Londerzeel castle Refuse layer 13–14 78 79 Mechelen Lamot Refuse layer 9–12 80 Van Neer and Ervynck unpubl. Mechelen Steen Cesspit 13B–14A 81 and 82 83 Mechelen Veemarkt Cesspit 14–15 84 Van Neer and Ervynck unpubl. Raversijde Refuse layer 15 85 Van Neer and Ervynck unpubl. Tongeren Hasseltse Poort Cesspit 17–18 61 61 Tournai Clo^ıtres Refuse layer 3–4 86 87

implies that no residual or intrusive material is present within the inland sites. The non-urban sites at Ename (the 11th c. ‘portus’, collections. All contexts were primary deposits, i.e. not reworked the 15th–16th c. ‘abbey kitchen’ and the 17th c. ‘abbey priory’) are after initial deposition. It is also important to note that although located near the bank of the river Scheldt. Fishing rights linked it is likely that the fish were consumed near the place where the with these sites strongly suggest that freshwater fish came from remains were found, they could derive from a biotope located far the river, or also from artificial carp ponds in the case of the away from the site. For marine fish in inland sites this is abbey contexts. Marine and estuarine species would have been a straightforward statement but it could also be true for fresh- purchased from traders visiting the site in the case of the portus, water species, for which, in historical times, trade cannot be or from the nearby urban market of Oudenaarde, in the case of excluded albeit that the overland transport was probably limited the younger, monastic contexts. The 13th–14th c. castle mound of to about 150 kilometres.44 However, the assumption made here Londerzeel was surrounded by a broad ditch that received its (but which is to be reviewed critically) is that the freshwater fish water from a brook that was part of the Scheldt basin. It is likely from an individual site are the product of local catches. that the freshwater fish originated from there. Urban markets Twelve of the 15 sites sampled (see Table 1, and the references were not near but itinerant traders could have visited the site. The therein) are located along the river Scheldt or one of its fishermen from the 15th c. village of Raversijde, located right tributaries (Fig. 1). The town of Tongeren, from which samples behind the coastal dunes, were very active in coastal and long were included from a single 17th–18th c. site, is located along the distance marine fishing (into northern waters off the English and

Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. river Jeker, which is part of the Meuse basin. Close to the town, Scottish coasts) but apparently also caught freshwater fish, most to the north, the origin of the Demer can be found, a river that is probably in brackish or freshwater creeks near the site. part of the Scheldt basin. Ieper, from which a 13th–14th c. context was used, is situated on the banks of the Ieperlee, a tributary of Stable isotope ratio analysis the Yser, a small coastal river in the western part of Belgium. Finally, bones have also been selected from the coastal site of When possible, large skeletal elements were selected so that Raversijde, a 15th c. fishing village, where besides marine fish, eel a single bone would be sufficient for isotopic analysis and in these was also found. Five contexts (12th c. Gent Belfortstraat, 10th– cases the reconstructed body length of the corresponding fish is 12th c. Gent portus,13th–14th c. Ieper Verdronken Weiden, 9th–12th provided in Table S1†. However, for certain small species such as c. Mechelen Lamot and 3rd–4th c. Tournai Clo^ıtres) represent smelt (Osmerus eperlanus) and herring (Clupea harengus), indi- general urban waste from refuse layers that could have been vidual bones were usually too light and it was necessary to take deposited by a large and diverse group of consumers. Freshwater several skeletal elements in order to arrive at a weight of 100 to fish from those sites may derive from the Scheldt basin (except 200 mg (a methodological step not uncommon in literature, see for Ieper) while species from marine and brackish waters must Szpak et al. (2009)).28 The same problem was sometimes represent imports. Five contexts (17th c. Antwerpen Koolkaai, encountered for eel (Anguilla anguilla) and in those cases 14–15th c. Dendermonde De Cop, 13th–14th c. Mechelen Steen, numerous small vertebrae were selected for analysis. Doing so, 14–15th c. Mechelen Veemarkt and 17th–18th c. Tongeren Has- bones were always taken from the same closed stratigraphic seltse Poort) represent the consumption refuse of a single urban context, but it is unlikely that they are all from the same household, deposited in a cesspit. Freshwater fish from these individual. contexts may have been fished in local waters (the Scheldt basin, Collagen extraction was performed at the Department of except for Tongeren) but also could have been, just as the marine Human Evolution, Max Planck Institute for Evolutionary species, purchased from the market. Fish from brackish waters Anthropology in Leipzig, Germany and at the Department of may represent a local catch in the Scheldt estuary in the case of Archaeological Sciences at the University of Bradford, UK using Antwerpen, but must have been imported at the four other, more the protocol outlined in Richards and Hedges (1999),24 modified

810 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012 View Article Online

to include a final stage of ultrafiltration (cut-off > 30 kD) prior to lyophilisation as described in Brown et al. (1988).45 The purified

collagen was weighed into tin capsules and combusted to CO2 and N2 in an elemental analyzer (Flash EA 2212, Thermo- Finnigan, Bremen, Germany) coupled to a continuous-ﬂow isotope ratio-monitoring mass spectrometry (ThermoFinnigan Delta XP, Bremen, Germany). Replicate measurement errors on known standards were less than 0.2& for both d13C and d15N.

Results Data obtained All of the information about the data obtained is summarized in Table 2 (mean d13C and d15N values and number of samples), while the individual results are listed in Table S1†. The latter table gives details not only about the successful measurements but also about the considerable portion of the sample set that did not produce reliable data. For the large numbers of pike, roach, and eel that were isotopically analyzed, these results are plotted for the C : N ratios vs. the d13C and d15N values in Fig. 2a and b. All of the acceptable carbon and nitrogen isotopic results are plotted by individual taxon in Fig. 3a and by water habitat type and fish ecology in Fig. 3b. The taxa sampled have a large range of d13C values (28.2& to 12.9&) (Fig. 3a and b). The resident freshwater fish have values ranging from 28.2& to 20.2&, while the resident marine fish cluster between 15.4& and 13.0&. Eel, a catadromous species (mostly living in freshwater but migrating into the sea to spawn), plots between 24.1& and & 17.7 , the anadromous fish (living in marine environments but Fig. 2 (a) d13C results plotted in relation to the measured C : N ratios for migrating into freshwater to spawn) plot into two separate the species: roach, pike, eel. The shaded rectangle represents C : N ratios groups: one that aligns with the freshwater fish and one that is between 2.9 and 3.6 which are defined as acceptable for stable isotope located with the marine fish (Fig. 3b, see below for further ratio analysis of bone collagen.47 (b) d15N results plotted in relation to the explanation). In addition, the d15N results show a large range measured C : N ratios for the species: roach, pike, eel. The shaded rect- (7.2& to 16.7&) too. In Fig. 4a and b (and Table 2), the mean angle represents C : N ratios between 2.9 and 3.6 which are defined as 47 13 15 Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. (SD) d C and d N values of all individual taxa are shown in acceptable for stable isotope ratio analysis of bone collagen. relation to the type of aquatic habitat in which they primarily

Table 2 Summary of isotopic results for ﬁsh from archaeological sites from the historical period, Belgium (standard deviations have only be calculated for N >2)

Ecology N Species (or taxon) Common name Mean d13C SD Mean d15N SD

Freshwater 11 Rutilus rutilus Roach 23.9 1.3 13.6 0.7 Freshwater 1 Leuciscus idus Ide 28.2 — 13.4 — Freshwater 1 Tinca tinca Tench 22.8 — 11.5 — Freshwater 2 Cyprinus carpio f. domestica Carp 21.3 — 10.9 — Freshwater 12 Esox lucius Pike 24.7 1.4 14.5 2.4 Freshwater 1 Coregonus sp. Whitefish 23.0 — 12.7 — Catadromous 14 Anguilla anguilla Eel 21.6 2.1 12.9 2.4 Anadromous 3 Osmerus eperlanus Smelt 20.0 0.9 14.3 1.3 Anadromous 3 Acipenser sp. Sturgeon 14.1 0.7 13.0 0.2 Anadromous 1 Alosa sp. Shad 13.0 — 13.4 — Marine 2 Pleuronectes platessa Plaice 14.1 — 11.8 — Marine 1 Platichthys flesus Flounder 15.4 — 14.3 — Marine 2 Pleuronectidae Flatfish 14.8 — 10.7 — Marine 1 Hippoglossus hippoglossus Halibut 13.7 — 14.4 — Marine 1 Clupea harengus Herring 15.0 — 12.0 — Marine 4 Melanogrammus aeglefinus Haddock 14.5 0.5 14.0 0.5 Marine 2 Merlangius merlangus Whiting 13.5 — 14.9 — Marine 1 Gadus morhua Cod 13.0 — 14.9 —

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 811 View Article Online Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01.

Fig. 3 (a) Carbon and nitrogen stable isotope ratio results from all of the fish taxa (n ¼ 63) that produced acceptable C : N ratios. (b) Carbon and nitrogen stable isotope ratio results from all of the fish taxa (n ¼ 63) that produced acceptable C : N ratios, classified by ecological type.

reside, and to their migratory behavior. In Fig. 5a and b, the (Table S1†), indicative of well-preserved collagen.46 Recently, isotopic values are plotted against reconstructed standard body there has been some debate about the correct range that can be lengths (SL in cm), for pike, roach and eel. Fig. 6a and b plot d13C used for C : N ratios for archaeological fish specimens. Grupe and d15N results by site in chronological order for the same three et al. (2009)17 have argued that the C : N ratio range can be species. extended to 4.0 based on a number of experimental observations and literature references. However, Szpak (2011)10 has countered that the isotopic results from fish should only be used if they fall Discussion within the traditional range (2.9–3.6) based on the amino acid composition of fish collagen. While it is tempting to extend the Low success rate of collagen extraction useable C : N ratio for our fish results to 4.0 (this would give 105 While 157 individual specimens were prepared for analysis, only useable results), we decided to only include and discuss samples 63 had C : N ratios within the acceptable range of 2.9–3.6 with C : N ratios between 2.9 and 3.6.

812 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012 View Article Online Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01.

Fig. 4 (a) Mean SD d13C results plotted in relation to individual fish taxa that are classified by ecological type. (b) Mean SD d15N results plotted in relation to individual fish taxa that are classified by ecological type.

The low success rate (ca. 40%) is likely the result of specimens were a dark brown to black color and were diagenetic contamination during burial. Since fish have excavated from refuse contexts and cesspits, rich in organic a high lipid content and lipids are 13C-depleted relative to material, which represent aggressive environments in terms of proteins,47 the presence of lipid contamination in the collagen post-depositional chemical alteration of bone. This could should cause a shift to more negative d13C values. While have resulted in these contaminants becoming bound or some of the pike, roach and eels samples do seem to get cross-linked to the collagen matrix and thus difficult to lighter in d13C with an increase in the C : N ratio, little eliminate. Finally, higher C : N ratios in fish collagen could correlation is observed (Fig. 2a). Thus, some lipid contami- be the result of selective chemical hydrolysis of amino acids, nation might be present, but it is likely that the majority of specifically the amino acids with low C : N ratios like the contamination is the result of the impact of soil glycine.10 At the present time, the exact cause(s) of these high components such as humic and fulvic acids from the burial C : N ratios of fish collagen remains elusive and further context. In addition, it is worth noting that all the bone systematic research in this area is necessary.

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 813 View Article Online Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01.

Fig. 5 (a) d13C results plotted against the estimated standard length (SL in cm) for the roach and pike. (b) d15N results plotted against the estimated standard length (SL in cm) for the roach and pike.

Freshwater fish a lower trophic level. Although these values are seemingly in disagreement with the size-related shift in diet described above, The 11 specimens of roach (Rutilus rutilus) that gave acceptable an explanation might be in the provenance of this fish. It comes d13 & data (C : N range) have mean C values of 23.9 1.3 and th 15 from a 17 c. context at the Ename abbey that owned and d N values of 13.6 0.7& (1 SD) (Fig. 4a and b). Roach feed on 49 exploited fish ponds, mainly for carp. It is possible that the aquatic invertebrates (mainly planktonic crustaceans), detritus, maintenance of these ponds involved regular emptying that algae, higher plants, but adults larger than 15 cm can feed on caused adverse conditions for mollusks to grow and as a result mollusks.48 The individuals between 10 and 20 cm SL display the roach remained a plant feeder. Finally, when the d13C and a large variation in d13C(25.1& to 21.4&) and d15N (13.0& d15N results are plotted by site in chronological order (Fig. 6a and to 15.3&) results (Fig. 5a and b), and this reflects the fact that b), no significant changes in isotope values through time are these fish had different diets and were recovered from different observed. sites and time periods. The largest specimen (30 cm SL) shows 13C The single specimen of ide (Leuciscus idus) comes from the and 15N depleted values, which suggest that it was feeding at same aforementioned 17th c. abbey context and has the most

814 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012 View Article Online Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01.

Fig. 6 (a) Mean SD d13C results for the roach, pike, and eel diachronically plotted by archaeological site. (b) Mean SD d15N results for the roach, pike, and eel diachronically plotted by archaeological site.

13C-depleted value (28.2&) of all the fish studied but a d15N but also regularly eat plant material48 which is in agreement with value (13.4&) that is comparable to that of the roaches. Ide also the relatively low d15N result observed here. Possibly, this fish eat mainly larger invertebrates such as crustaceans, mollusks, was captured from the ditch of Londerzeel castle. and insect larvae, but large individuals can become piscivorous The two specimens of carp (Cyprinus carpio f. domestica) have and feed on other cyprinids.48 mean results of 21.3& for d13C and 10.9& for d15N. The The single tench (Tinca tinca) has a d13C value (22.8&) close specimen from the site of Ename abbey had isotopic results to those of the roaches but one of the lowest d15N values (11.5&) similar to the tench and most probably came from a cultured fish of all of the cyprinids. Tench primarily feed on bottom inverte- pond near the monastery. In contrast, the second carp came from brates such as worms, crustaceans, mollusks and insect larvae the coastal site of Raversijde and had a d13C value (20.2&)

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 815 View Article Online

which is the most elevated among the investigated cyprinids due to the fact that numerous whitefish populations have now (Table S1†). This higher d13C value from the Raversijde specimen disappeared in the northeastern Atlantic region as a result of is consistent with origins in a coastal creek or pond with some overfishing and pollution. The literature mentions three species brackish water influx. Carp mainly feed on benthic invertebrates that lived in the North Sea basin and its adjacent rivers.48,52,53 The such as insect larvae, crustaceans and mollusks.48 first, the houting (Coregonus oxyrhinchus), is anadromous and The 12 specimens of pike (Esox lucius) that produced good lives along the coast and in estuaries, while it seasonally ascends results have mean SD values of 24.7 1.4& for d13C and rivers for spawning. The second, the European whitefish (Cor- 14.5 2.4& for d15N. Among the freshwater fish, the pike have egonus lavaretus), has been reported in brackish waters but would the second most 13C-depleted mean values but the most 15N- more frequently occur in freshwater. In countries where it still enriched mean values (Fig. 4a and b). Young individuals feed survives it typically lives in relatively large and deep lakes, but it mainly on invertebrates such as freshwater shrimps and water is also occasionally found in rivers associated with lakes.48 The lice but can also consume small fish. As they mature, pike mainly third species, the vendance (Coregonus albula), mainly lives in feed on fish, including their own species. Pike larger than 50 cm freshwater, but there also exist marine populations that enter are primarily piscivorous, but it has been observed that in places freshwater for spawning. However, Kottelat and Freyhof,54 who where abundant prey is available they can still eat a large amount revised the family, concluded that most published information of invertebrates.48 Besides fish, adult pike eat many other verte- does not allow firm conclusions about the identity and the brates (dead or alive) that are not too large to swallow, including distribution of the species. For Belgium, a review of the fishery small mammals (water voles and water shrews), waterfowl, and literature for the mid-19th century onwards55 showed that the amphibians. While the average d15N values of the pike are rela- only coregonid species that had been mentioned was labelled tively high, it is surprising that they are not even more 15N- Coregonus oxyrhinchus56 and was said to only seasonally enter enriched compared to the other freshwater fish, as their feeding the Scheldt basin. In the early 20th century, houting was still ecology would suggest. Hence it seems that the medium-sized described as reproducing in the Scheldt estuary, but after 1913 pike from these late medieval sites had, on average, a relatively the species was no longer mentioned.55 This pilot study now small proportion of higher trophic level organisms in their diet. suggests that the species mentioned in this older fishery literature There are even two individuals with d15N values that are lower is different from the one whose bones were found at Londerzeel than those of the cyprinids which are the most common prey of Castle (13th–14th c.). This fish has an isotopic signature typical of the pike (Fig. 3a), and this is possibly the result of ecological a fish that spent most, if not all, of its life in freshwater. Thus, the difference at the base of the food chain from the different sites. A isotopic results hint to the fact that an unknown coregonid large number of environmental variables can influence the population, or even species, lived in the Scheldt basin during the isotopic composition of aquatic producers in aquatic ecosystems. medieval period. Nevertheless, more isotopic and genetic One of the most important factors in determining the isotopic research is necessary to confirm this potential finding. composition of freshwater organisms is the trophic status of the actual water bodies (e.g. oligotrophic, mesotrophic, eutrophic, Catadromous eels hypertrophic), since this can significantly impact the isotopic compositions of planktonic organisms and organic matter, and The 14 eels (Anguilla anguilla) that produced acceptable isotopic 50,51 13 Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. thus the fish that consume these prey items. Although it is results show a wide variation in both their d C values (between known that the diet of pike changes with size and can be very 24.1& and 17.7&; mean SD ¼21.6 2.1&) and d15N variable at different life stages, the d13C values only show a weak results (between 7.2& and 15.5&; mean SD ¼ 12.9 2.4&) negative correlation with body length such that the values (Fig. 4a and b). The distribution of the data points in Fig. 3a become 13C-depleted with increasing size and this might be shows that the eels lived in different water types (most probably related to the fact that more mature pike live in deeper waters48 both freshwater and brackish) and fed at many different trophic (Fig. 5a). In contrast, the d15N values show almost no correlation levels. This is in agreement with the wide-ranging diet of eels with the estimated pike body length (Fig. 5b). Two individuals which consists of virtually all aquatic fauna.48 There appears to from the sites of Dendermonde (14th–15th c.) and Mechelen (13th– be a trend whereby invertebrates become proportionally less 14th c.) have the lowest d15N values of all the sampled pike, which important compared to fishes, as the eels grow larger. However, is particularly surprising as they are among the larger individuals there is also significant variation from one population to another. analyzed (35–40 cm) from the sites. Their low d15N values thus The specimen from the coastal site of Raversijde (Fig. 1) has the cannot be explained as a result of different size-related feeding lowest d15N value (7.2&) of all of the eels and a freshwater d13C habits. However, feeding habits of pike can differ considerably signature (22.2&). It is believed that this eel spent most of its from one ecosystem to the other48 and the outliers from life in one of the small freshwater creeks near the site. The 13 Mechelen and Dendermonde may therefore identify fish that other eel specimens fall into two clusters: one group of six indi- were brought in from other locations where they were feeding on viduals shows a freshwater isotopic signal (d13C ¼23.7 0.7&; more low trophic invertebrates. Finally, the pike were also d15N ¼ 14.7 0.5&) and another group of seven specimens diachronically graphed by site but the small sample size makes it shows a brackish influence (d13C ¼19.8 1.1&; d15N ¼ 12.2 difficult to detect any significant trends (Fig. 6a and b). 1.8&). The most 13C-depleted specimens are from the two inland The single whitefish (Coregonus sp.) measured produced an sites of Ename and Mechelen, far from the mouth of the Scheldt isotopic signature typical of a freshwater fish (d13C ¼23.0&; River where no tidal influence is felt, and thus can likely be d15N ¼ 12.7&). The taxonomical relationships and native ranges considered locally caught (Fig. 1 and Table S1†). At Ename, of the different species from this genus are still poorly understood fishing was possible in the Scheldt River itself, but the abbey also

816 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012 View Article Online

owned a series of large fish ponds that were used to culture Additionally, as already described in historical sources going carp.49 Excavations concluded that freshwater fish consumption back to the 19th century,55 the large distance from the North Sea from this site was dominated by these carp (about 70% of all to the Jeker River (part of the Meuse basin) has always been freshwater fish bone) and was followed by eel (about 20% of all considered to offer a good explanation for the fact that anad- freshwater fish bones).42 The eel may also have been captured in romous smelt never reached the Belgian portion of the Meuse the fish ponds, as suggested by the discovery of an eel trap in River. The 13C-depleted result of the smelt from Tongeren now a ditch at the site.42 The d13C and d15N values of the eels, hints at the possibility that there could have been a land-locked diachronically compared by site (Fig. 6a and b), possibly show population that once lived in the Meuse basin. However, more a trend for Mechelen. Three sites (Lamot, Steen, Veemarkt) were isotopic analysis is needed on a large number of archaeological sampled for eel but only the oldest site of Lamot (9th–12th c.) samples to confirm this possibility. yielded specimens that were very 13C-depleted (Fig. 6a). Four out The three sturgeon bones that were analyzed had initially been of the five eels from Mechelen Lamot display highly 13C-depleted identified as European sturgeon (Acipenser sturio), but new freshwater values which could suggest that they were locally archaeozoological and palaeogenetic data suggest that another caught. The fifth specimen has a higher d13C and a lower d15N species needs to be taken into account as well, namely the value than the others, but falls within the variation of the eels Atlantic sturgeon (A. oxyrinchus).62,63 Both species, which have from other sites and later time periods (Table S1†). Those eels, in the past sometimes been viewed as subspecies, have a very with more 13C-enriched values, are all from the sites of Steen (late similar feeding and migratory behavior. Young sturgeons feed 13th–early 14th) and Veemarkt (14th–15th c.). As all the investi- on bottom invertebrates in rivers and estuaries where they spend gated eels were of similar size, the 13C-enriched results could the beginning of their lives. Once they descend into the ocean, the suggest that they were no longer locally caught, but were brought sturgeons feed on larger marine worms, crustaceans and in from more downstream areas of the Scheldt basin, in or nearer mollusks, and they also consume small bottom-dwelling fish such to the estuary. In addition, these observed isotopic differences in as sand-eels and gobies.48 After several years, when they are the eels at the town of Mechelen do not likely reflect the histor- mature, sturgeon stop feeding and move back into the river in ically known rise in organic pollution of the river through time, which they were born for spawning. The sturgeons sampled have as a result of urbanization.57 Increased input of organic material mean SD d13C(14.1 0.7&) and d15N (13.0 0.2&) values. into waterways could have resulted in eutrophication of rivers The fact that these fish spend most of their lives in the ocean and canals which could have affected the spectrum of fish explains their marine d13C signatures, whereas their d15N values species58 as well as the isotopic signatures of the fish surviving in are a reflection of their diet of marine invertebrates (Fig. 4a and polluted waters.59 However, the diachronic trend in d13Cat b, Table 2). Mechelen is not likely explained by such a phenomenon as this Using isolated bones, it is difficult to identify the shad remains should have resulted in higher d15N values, which were not to species level, but taking into account the geographical distri- observed (Table S1†). Still, the number of specimens studied was bution of the fish, two species are known to occur in north- small and more isotopic work is necessary to confirm whether western Europe: allis shad (Alosa alosa) and twaite shad (Alosa there was a decrease in locally caught fish at sites such as fallax). Both are coastal fish that are also capable of living in Mechelen during the medieval period. large estuaries. During the spawning migration, these fish ascend

Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. rivers above the influence of the tide. In particular the allis shad are known to travel upstream for several hundreds of kilometres. Anadromous fish When young, shad feed on riverine or estuarine invertebrates, Smelt (Osmerus eperlanus) are found in coastal waters and but when they mature they feed mainly on marine invertebrates estuaries but migrate in large numbers up rivers for spawning. and to some extent on small fish. This is especially true for the Depending on the region, they can stay in the lower reaches of twaite shad which have been found to include an appreciable rivers between a few weeks to several months, but land-locked number of young sprat and herring in their diet.48 The single populations have also been reported from Scandinavia, Great unidentified shad in this study has the most positive d13C value Britain and the Netherlands.48,60 The two archaeological samples (13.0&) of all investigated fish indicating that it spent most of from Antwerpen (mean d13C ¼19.5&; d15N ¼ 14.6&) are its life in the sea, rather than in an estuary (Fig. 4a). The d15N consistent with a brackish d13C signature suggesting that they value (13.4&) is lower than many of the marine fish suggesting were locally captured in the estuary of the Scheldt River (Fig. 4a that it was feeding on invertebrates or lower trophic level juvenile and Table S1†). However, the results for the single smelt sample fish such as clupeiforms (Fig. 4b). from Tongeren (d13C ¼21.0&; d15N ¼ 13.7&) differ from those of the Antwerpen specimen, with a d13C value closer to Marine fish those of freshwater species (Fig. 4a and Table S1†). This finding possibly contradicts the explanation that was given for the The three species of the Pleuronectidae family represented in this presence of smelt at Tongeren in the initial publication of the study: plaice (Pleuronectes platessa), flounder (Platichthys flesus), finds61 where it was postulated that smelt were imported from and halibut (Hippoglossus hippoglossus) are commonly found on the estuary of the Scheldt as it seemed unlikely that they would sites along the northwestern Atlantic. The plaice have a typical have migrated as far as Tongeren to reproduce (see Fig. 1). marine d13C signal (14.1&) and relatively low mean d15N value Historically, smelt never ascended the Demer River (part of the (11.8&) (Fig. 4a and b). Juvenile plaice can sometimes live in Scheldt basin) and the upper reaches of this river were likely estuaries, but the species is essentially a marine coastal fish that unsuitable as a living and spawning area for the species. swims into deeper water as it matures.64 Their diet consists

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 817 View Article Online

mainly of bivalve mollusks and annelid worms and this is in line (14.4&) isotopic results place the analyzed specimen within the with the lower d15N values observed in this study. range of the high trophic level of the gadids family (see below; The single flounder that was studied has a d13C value of cod, haddock, whiting; Fig. 4a and b). 15.4&, which is relatively low compared to the other marine The single herring (Clupea harengus) displays a relatively low fish, but not sufficiently 13C-depleted to be classified as an d15N value (12.0&; Fig. 4b) which is consistent with the fact that estuarine fish (Fig. 4a). However, the d15N value of the flounder it mainly feeds on small invertebrates.64 Herring live in marine (14.3&) is relatively high compared to the plaice (Fig. 4b). This coastal waters, which is consistent with its d13C value of 15&, is likely the result of a diet that includes not only bivalves, but early juveniles are also very abundant in estuaries, such as annelids, and crustaceans but also small benthic fish (e.g. that of the Scheldt, which serve as a nursery.65 gobies (Gobiidae) and sandeels (Ammodytes sp.)).48 In relation The three members of the Gadidae family (haddock, cod and to the other flatfish, the flounder has the highest tolerance whiting) that were investigated all have relatively enriched 13C toward changes in salinity.64 It is a marine, coastal fish occur- and 15N results, illustrating that these species are marine high ring in the southern North Sea, but is also frequently found in trophic level feeders (Fig. 4a and b, Table 2). The mean SD the Scheldt estuary and can also migrate upstream into fresh- values of the four haddock (Melanogrammus aeglefinus) are water. Since feeding continues during these prolonged stays in 14.5 0.5& for d13C and 14.0 0.5& for d15N. The two estuaries or during the long upstream migrations, the isotopic specimens of whiting (Merlangius merlangus) that were studied signal can be expected to reflect the biotope in which the had mean d13C(13.5&) and d15N (14.9&) values. The single flounder spent the majority of its time feeding. This could cod (Gadus morhua) had a d13C value of 13.0& and a d15N value potentially help to overcome problems that are sometimes of 14.9&, which are consistent with other recently published encountered when trying to document early inland trade in isotopic data from cod which gave mean values of d13C ¼13.5 marine fish using archaeological fish bone. Inland finds of 0.8&; d15N ¼ 15.6 1.0&.19 Based on the analysis of stomach flatfish can only be considered as being imported from the coast contents, these three carnivorous species consume different in cases where plaice or dab, which do not ascend rivers beyond amounts of fish: cod > whiting > haddock.64,66 The haddock is the estuaries, are identified. In contrast, flounder found at an the least voracious and carnivorous of the three species as it feeds inland site may well represent the remains of locally captured mainly on herring fry, echinoderms, polychaetes, mollusks and fish. As mentioned above, flatfish are not always easily identi- crustaceans. Whiting have a varied diet based mainly on crus- fied by isolated bones and in cases where the identification of taceans and small fish. In contrast, cod is a highly voracious and inland finds needs to be left as ‘plaice/flounder/dab’ their carnivorous species that feeds on other fish, primarily herring of significance with regard to trade remains uncertain. However, which it follows migrating shoals. Due to the small samples of this pilot study shows that stable isotope analysis may help to this present study, it is difficult to comment on the variation in solve this problem. The isotope results of the flounder the trophic level of these three species but the haddock do indeed consumed at ‘Antwerpen Koolkaai’ plot with those of the have lower d15N values compared to the whiting and cod (Fig. 4b marine specimens and it was therefore likely caught at sea. and Table 2). More research is necessary on a larger number of They are not consistent with a fish that spent its life in the archaeological samples from across Europe to see if this is a real estuary. trend.

Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. The two specimens of ‘unidentified flatfish’ (Pleuronectidae) are rare finds from early archaeological sites (Roman and early Conclusions high medieval). One was excavated from Gent (d13C ¼15.3&; d15N ¼ 10.4&), a location where the influence of the marine The results of this pilot study indicate that human dietary water incursion can still be felt in the Scheldt River, and dates reconstructions, on the basis of carbon (d13C) and nitrogen (d15N) between the 10th and 12th century (Fig. 1). In the early 20th stable isotope ratios measured in bone collagen, will need to take century, flounder was still caught in Gent.55 The other uniden- into account the broad variation in isotope values of fish, one of tified flatfish specimen (d13C ¼14.3&; d15N ¼ 11.1&)isa3rd– the food categories that became increasingly important in 4th c. AD find from Tournai which is located farther upstream in historical times. The samples measured not only show the the freshwater part of the Scheldt River. If these two flatfish were expected differences between marine, estuarine and freshwater flounders, they could, theoretically, both have been caught species, but also the significant variation which appears to exist locally. Their isotopic signatures, however, most resemble those within single species. Diachronic trends could not be established of plaice (low d15N values), and therefore probably represent due to small sample sizes, and neither could age-related effects be either this species or the other marine member of the Pleuro- detected on a statistically significant level. Interpretations are nectidae family, dab. This again suggests that isotopic ratios have further complicated by the possible presence of populations in the potential to allow a better understanding of the rise of fish areas where they now no longer exist, sometimes characterized trading in the future. by migration behavior that differs from the extant populations. Halibut is rarely encountered at Belgian archaeological sites, As a result of the measurements taken from the archaeological and then only from the 15th c. onwards, when fishermen started fish remains, it is also clear that important ecological information exploiting the northern waters more intensively where this can be gained that is of interest not only to the study of a species, species occurs.38 While a member of the family Pleuronectidae, but also for the knowledge of the ecology of former environ- halibut reside in marine, deep waters and it is considered ments. In this way, future stable isotope analyses will also help to a voracious carnivorous species feeding on fish and various develop the zoogeography of the past and present fish fauna, and invertebrates.64 Fittingly, the carbon (13.7&) and nitrogen will add to the construction of reference conditions for fishery

818 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012 View Article Online

and nature management.67 From the viewpoint of archaeology, T. C. O’Connell, T. de Roo and M. P. Richards, J. Archaeol. Sci., the isotope results may, in some cases, help in identifying less 2011, 38, 1516–1524. 20 R. E. M. Hedges, J. G. Clement, C. D. L. Thomas and diagnostic fish bone remains to the species’ level. Economic T. C. O’Connell, Am. J. Phys. Anthropol., 2007, 133, 808–816. reconstructions may benefit from information obtained through 21 M. J. Schoeninger and M. J. DeNiro, Geochim. Cosmochim. Acta, isotopic analysis about the provenance of fish consumed (e.g. 1984, 48, 625–639. local catch or import, local catch from different biotopes, trade 22 M. Sponheimer, T. Robinson, L. Ayliffe, B. Roeder, J. Hammer, B. Passey, A. West, T. Cerling, M. D. Dearing and J. Ehleringer, networks, etc.) or about the way in which pisciculture was Int. J. Osteoarchaeol., 2003, 13, 80–87. managed (e.g. through the characterisation of the ecology of 23 P. Szpak, T. J. Orchard, I. McKechnie and D. R. Grocke,€ J. Archaeol. artificial fish ponds). Sci., 2012, 39, 1553–1571. 24 M. P. Richards and R. E. M. Hedges, J. Archaeol. Sci., 1999, 26, 717– This broad scope pilot study must now be expanded to include 722. more material selected specifically to address archaeological, 25 R. E. M. Hedges and L. M. Reynard, J. Archaeol. Sci., 2007, 34, ecological, and zoogeographical questions. Examples of such 1240–1251. € targeted study projects could be the diachronic comparison of 26 K. Auerswald, M. H. O. M. Wittmer, A. Zazzo, R. Schaufele and H. Schnyder, J. Appl. Ecol., 2010, 47, 936–941. remains from a single species that is most likely locally caught, 27 S. Caut, E. Angulo, F. Courchamp and J. Figuerola, J. Appl. Ecol., from a single multi-period site, or the broad geographical 2010, 47, 948–954. comparison of remains of a single species, derived from many 28 P. Szpak, T. J. Orchard and D. R. Grocke,€ J. Archaeol. Sci., 2009, 36, synchronous populations. From the viewpoint of archaeology, 2734–2741. 29 R. L. France, Mar. Ecol.: Prog. Ser., 1995, 124, 307–312. the next step is to test whether the known shifts in consumption 30 D. O. Duggins, C. A. Simenstad and J. A. Estes, Science, 1989, 245, patterns documented by traditional fish bone studies are 170–173. detectable by stable isotope measurements from human skeletal 31 G. Schaal, P. Riera and C. Leroux, Estuar. Coast. Shelf Sci., 2009, 85, 565–572. material. 32 G. Schaal, P. Riera and C. Leroux, J. Sea Res., 2010, 63, 24–35. 33 S. C. Wainright, J. C. Haney, C. Kerr, A. N. Golovkin and M. V. Flint, Mar. Biol., 1998, 131, 63–71. Acknowledgements 34 T. Saino and A. Hattori, Deep-Sea Res., Part A, 1987, 34, 807–827. 35 Y. Cherel and K. A. Hobson, Mar. Ecol.: Prog. Ser., 2007, 329, 281– The contribution of WVN to this paper presents research results 287. of the Interuniversity Attraction Poles Programme – Belgian 36 R. K. Burton and P. L. Koch, Oecologia, 1999, 119, 578–585. Science Policy. BTF and MPR would like to thank J.J. Hublin 37 S. D. Newsome, M. T. Clementz and P. L. Koch, Mar. Mammal Sci., and the Max Planck Society for funding this research. 2010, 26, 509–572. 38 A. Ervynck, W. Van Neer and M. Pieters, How the North was Won (and Lost Again). Historical and Archaeological Data on the References Exploitation of the North Atlantic by the Flemish Fishery, in Atlantic Connections and Adaptations: Economies, Environments and 1 H. P. Schwarcz and M. J. Schoeninger, Yearbook of Physical Subsistence in Lands Bordering the North Atlantic (Symposia of the Anthropology, 1991, 34, 283–321. Association for Environmental Archaeology 21), ed. R. A. Housley 2 M. J. Schoeninger, Evol. Anthropol., 1995, 4, 83–98. and G. M. Coles, Oxbow, Oxford, 2004, pp. 230–239. 3 Biological Anthropology of the Human Skeleton, ed. M. A. Katzenberg 39 W. Van Neer and A. Ervynck, The Zooarchaeological Reconstruction and S. R. Saunders, New York, Wiley-Liss Inc., 2000. of the Development of the Exploitation of the Sea: a Status 4 J. A. Lee-Thorp, Archaeometry, 2008, 50, 925–950. Quaestionis for Flanders, in Fishery, Trade and Piracy. Fishermen Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. 5 J. C. Sealy, N. J. van der Merwe, J. A. L. Thorp and J. L. Lanham, and Fishermen’s Settlements in and Around the North Sea Area in the Geochim. Cosmochim. Acta, 1987, 51, 2707–2717. Middle Ages and Later (Archeologie in Vlaanderen Monografie 6), 6 M. A. Katzenberg, H. P. Schwarcz, M. Knyr and F. J. Melbye, Am. ed. M. Pieters, F. Verhaeghe and G. Gevaert, Flemish Heritage Antiquity, 1995, 60, 335–350. Institute, Brussel, 2006, pp. 95–103. 7 M. P. Richards, R. E. M. Hedges, T. I. Molleson and J. C. Vogel, J. 40 W. Van Neer, A. Ervynck, W. Wouters, L. Muylaert, J. Barrett, Archaeol. Sci., 1998, 25, 1247–1252. M. P. Richards and C. Johnstone, The Rise of Seafish 8 H. Bocherens, M. Mashkour, D. G. Drucker, I. Moussa and Consumption in Inland Flanders (Belgium), in Cod and Herring: D. Billiou, J. Archaeol. Sci., 2006, 33, 253–264. The Archaeology and Early History of Intensive Fishing, Oxbow, 9 C. Bourbou, B. T. Fuller, S. Garvie-Lok and M. P. Richards, Am. J. Oxford, in press. Phys. Anthropol., 2011, 146, 569–581. 41 R. C. Hoffmann, Am. Hist. Rev., 1996, 101, 631–669. 10 P. Szpak, J. Archaeol. Sci., 2011, 38, 2258–2272. 42 W. Van Neer and A. Ervynck, Archeologie en vis (Herlevend verleden 11 N. J. van der Merwe, S. Pfeiffer, R. F. Williamson, K. O. Allegretto 1), Instituut voor het Archeologisch Patrimonium, Zellik, 1993, p. 96 and M. A. Katzenberg, J. Anthropol. Archaeol., 2003, 22, 245–261. (in Dutch). 12 C. Bosl,€ G. Grupe and J. Peters, Int. J. Osteoarchaeol., 2006, 16, 296– 43 W. Wouters, L. Muylaert and W. Van Neer, Archaeofauna, 2007, 16, 315. 33–95. 13 M. J. Miller, J. M. Capriles and C. A. Hastorf, J. Archaeol. Sci., 2010, 44 R. C. Hoffmann, Environ. Hist., 2001, 7, 131–167. 37, 317–327. 45 T. A. Brown, D. E. Nelson, J. S. Vogel and J. R. Southon, 14 O. Nehlich, D. Boric, S. Stefanovic and M. P. Richards, J. Archaeol. Radiocarbon, 1988, 30, 171–177. Sci., 2010, 37, 1131–1139. 46 M. J. DeNiro, Nature, 1985, 317, 806–809. 15 G. Muldner€ and M. P. Richards, J. Archaeol. Sci., 2005, 32, 39–48. 47 M. J. DeNiro and S. Epstein, Science, 1977, 197, 261–263. 16 G. Muldner€ and M. P. Richards, Am. J. Phys. Anthropol., 2007, 134, 48 P. S. Maitland and R. N. Campbell, Freshwater Fishes, Harper 162–174. Collins, London, 1992, p. 368. 17 G. Grupe, D. Heinrich and J. Peters, J. Archaeol. Sci., 2009, 36, 2125– 49 G. Tack, A. Ervynck and G. Van Bost, De monnik-manager. Abt De 2144. Loose in zijn abdij t’Ename, Davidsfonds, Leuven, 1999, p. 240 (in 18 L. J. Reitsema, D. E. Crews and M. Polcyn, J. Archaeol. Sci., 2010, 37, Dutch). 1413–1423. 50 J. Grey, R. I. Jones and D. Sleep, Oecologia, 2000, 123, 232–240. 19 J. H. Barrett, D. Orton, C. Johnstone, J. Harland, W. Van Neer, 51 B. H. Gu, C. L. Schelske and M. N. Waters, Fundam. Appl. Limnol., A. Ervynck, C. Roberts, A. Locker, C. Amundsen, I. B. Enghoff, 2010, 178, 29–41. S. Hamilton-Dryer, D. Heinrich, A. K. Hufthammer, 52 H. C. Redeke, De Visschen Van Nederland, Sijthof, Leiden, 1941, p. A. K. G. Jones, L. Jonsson, D. Makowiecki, P. Pope, 331 (in Dutch).

This journal is ª The Royal Society of Chemistry 2012 J. Anal. At. Spectrom., 2012, 27, 807–820 | 819 View Article Online

53 G. Duncker, Die Fische der Nordmark, De Gruyter, Hamburg, 1960, 73 B. Cooremans, A. Ervynck and W. Van Neer, Archeologie in p. 432 (in German). Vlaanderen, 1993, 3, 419–442 (in Dutch). 54 M. Kottelat and J. Freyhof, Handbook of European Freshwater Fishes, 74 M. C. Laleman, D. Lievois and P. Raveschot, Stadsarcheologie. Publications Kottelat, Cornol, Switzerland, 2007, p. 646. Bodem en Monument in Gent, 1986, 10, (3), 2–61 (in Dutch). 55 S. Vrielynck, C. Belpaire, A. Stabel, J. Breine and P. Quataert, De 75 W. Van Neer and A. Ervynck, Stadsarcheologie. Bodem en Monument visbestanden in Vlaanderen anno 1840–1950, Een historische schets in Gent, 1995, 19, (4), 5–11 (in Dutch). van de referentietoestand van onze waterlopen aan de hand van de 76 M. C. Laleman and G. Stoops, Stadsarcheologie. Bodem en Monument visstand, ingevoerd in een databank en vergeleken met de actuele in Gent, 1996, 20, (3), 57–60 (in Dutch). toestand, Instituut voor Bosbouw en Wildbeheer en Afdeling Water 77 M. Dewilde and S. Van Bellingen, Excavating a Suburb of Medieval (AMINAL), Groenendaal, D/2003/3241/325, 2003, p. 271 (in Dutch). Ypres (Belgium). Evidence for the Cloth Industry?, in Ypres and the 56 E. de Selys-Longchamps, Sur la pêche fluviale en Belgique, Bulletin de medieval cloth industry in Flanders. Archaeological and historical l’Academie royale des Sciences, des Lettres et des Beaux-Arts de contributions (Archeologie in Vlaanderen Monografie 2), ed. M. Belgique, 1867, tome 22, 579–610. Dewilde, A. Ervynck and A. Wielemans, Instituut voor het 57 F. Thomas, Hygiene, approvisionnement en eau et gestion Archeologisch Patrimonium, Zellik, 1998, pp. 57–76. hydrographique a Namur au XVe siecle, Annales de la Societe 78 ‘De Burcht’ te Londerzeel. Bewoningsgeschiedenis van een motte en een Archeologique de Namur, 1994, 68, 235–305. bakstenen kasteel (Archeologie in Vlaanderen Monografie I), ed. A. 58 C. Wolter, J. Minow, A. Vilcinskas and U. A. Grosch, Fish. Manage. Ervynck, Instituut voor het Archeologisch Patrimonium, Zellik, Ecol., 2000, 7, 97–104. 1994, p. 224 (in Dutch). 59 T. A. Schlacher, B. Liddell, T. F. Gaston and M. Schlacher- 79 A. Ervynck, W. Van Neer and P. Van der Plaetsen, Dierlijke resten, in Hoenlinger, Oecologia, 2005, 144, 570–584. ‘De Burcht’ te Londerzeel. Bewoningsgeschiedenis van een motte en een 60 H. Nijssen and S. J. de Groot, De vissen van Nederland, Koninklijke bakstenen kasteel (Archeologie in Vlaanderen Monografie I), ed. A. Nederlandse Natuurhistorische Vereniging, Utrecht, 1987, p. 224 (in Ervynck, Instituut voor het Archeologisch Patrimonium, Zellik, Dutch). 1994, pp. 99–170 (in Dutch). 61 W. Wouters, A. Ervynck, B. Cooremans, W. Van Neer and G. Van 80 Het ongeschreven Mechelen. Archeologisch onderzoek op de Grote Bulck, Archeologie in Vlaanderen, 1994, 4, 323–363 (in Dutch). Markt en de Veemarkt 2001–2003, ed. L. Lettany, Stedelijke Musea 62 A. Ludwig, U. Arndt, S. Lippold, N. Benecke, L. Debus, T. I. King Mechelen, Mechelen, 2003, pp. 70–71 (in Dutch). and S. Matsumura, BMC Evol. Biol., 2008, 8, 221. 81 Het Steen en de burgers. Onderzoek van de laatmiddeleeuwse 63 N. Desse-Berset and P. Williot, J. Appl. Ichthyol., 2011, 27, 263–268. gevangenis van Mechelen, ed. L. Troubleyn, F. Kinnaer, and A. 64 M. Poll, Faune de Belgique. Poissons marins,Musee royal d’Histoire Ervynck, Mechelen, Stad Mechelen, 2007, p. 237 (in Dutch). naturelle de Belgique, Brussels, 1947, p. 452 (in French). 82 L. Troubleyn, F. Kinnaer, A. Ervynck, L. Beeckmans, D. Caluwe, 65 J. Maes, A. Taillieu, P. A. Van Damme, K. Cottenie and F. Ollevier, B. Cooremans, F. De Buyser, K. Deforce, K. Desender, Estuar. Coast. Shelf Sci., 1998, 47, 143–151. A. Lentacker, J. Moens, G. Van Bulck, M. Van Dijck, W. Van 66 J. C. Quero, Les poissons de mer des peches^ françaises, Delachaux & Neer and W. Wouters, Journal of the Archaeology of the Low Niestle, Lausanne & Paris, 1997, p. 304 (in French). Countries, 2009, 1, 5–47. 67 W. Van Neer and A. Ervynck, Defining ‘Natural’ Fish Communities 83 A. Lentacker, W. Van Neer, A. Ervynck and K. Desender, De for Fishery Management Purposes: Biological, Historical, and dierlijke resten, in Het Steen en de burgers. Onderzoek van de Archaeological Approaches, in Ecologies and Economies in Medieval laatmiddeleeuwse gevangenis van Mechelen, ed. L. Troubleyn, F. and Early Modern Europe. Studies in Environmental History for Kinnaer and A. Ervynck, Mechelen, Stad Mechelen, 2007, pp. 133– Richard C. Hoffmann, ed. S. G. Bruce, Brill, Leiden & Boston, 154 (in Dutch). 2010, pp. 193–233. 84 Mechelse Vereniging voor Stadsarcheologie, Archaeologia 68 P. Van der Wee, M. Hendrickx and J. Veeckman, De Groote Schalien Mediaevalis, 1995, 18, 28 (in Dutch). Loove: een laatmiddeleeuws pand op de overgang van hout- naar 85 C. Kightly, M. Pieters, D. Tys and A. Ervynck, Walraversijde 1465, steenbouw, in Berichten en Rapporten over het Antwerps Provincie West-Vlaanderen & Instituut voor het Archeologisch Bodemonderzoek en Monumentenzorg 4, ed. J. Veeckman, Patrimonium, Brugge, 2000, p. 88 (in Dutch). Antwerpen, Stad Antwerpen, 2000, pp. 27–98 (in Dutch). 86 R. Brulet, C. Coquelet, A. Defgnee, F. Pigiere and L. Verslype, Les

Published on 05 April 2012. Downloaded by Universiteit Gent 03/07/2015 09:50:01. 69 J. Veeckman, W. Van Hoff, B. Cooremans, A. Ervynck and W. Van sites a «terres noires» a Tournai et le secteur des anciens clo^ıtres Neer, De inhoud van de afvalput van de Groote Schalien Loove: canoniaux. Etudes archeozoologique, palynologique et speuren naar de 17de-eeuwse bewoners, in Berichten en Rapporten contextualisation, in Terres noires. Actes de la table ronde de over het Antwerps Bodemonderzoek en Monumentenzorg 4, ed. J. Louvain-la-Neuve. 09-10 novembre 2001, Departement d’archeologie Veeckman, Antwerpen, Stad Antwerpen, 2000, pp. 115–190 (in et d’Histoire de l’Art et Centre de Recherches d’Archeologie Dutch). Nationale, Louvain-la-Neuve (Collection d’Archeologie Joseph 70 D. Beeckman and G. Lambrecht, De Cop doorgespoeld. Een 16e- Mertens, XIV. Publications d’Histoire de l’Art et d’Archeologie de eeuwse beerputvulling anders bekeken, Stadsbestuur Dendermonde, l’Universite catholique de Louvain), ed. R. Brulet and L. Verslype, Dendermonde, 2007, p. 144 (in Dutch). Departement d’archeologie et d’histoire de l’art, Louvain-la-Neuve, 71 D. Callebaut, Castrum, Portus und Abtei von Ename, in Burgen der 2004, pp. 152–172 (in French). Salierzeit. Teil 1. In den nordlichen Landschaften des Reiches, ed. H. 87 F. Pigiere, Evolution de l’economie alimentaire et des pratiques W. Bohme,€ Romisch-Germanischen€ Zentralmuseum, Mainz, 1991, d’elevage de l’Antiquite au haut Moyen Age en Gaule du nord. Une pp. 291–309 (in German). etude regionale sur la zone limoneuse de la Moyenne Belgique et du 72 A. Ervynck and W. Van Neer, Archeologie in Vlaanderen, 1992, 2, sud des Pays-Bas (B.A.R. International Series 2035), Archaeopress, 419–434 (in Dutch). Oxford, 2009, p. 276 (in French).

820 | J. Anal. At. Spectrom., 2012, 27, 807–820 This journal is ª The Royal Society of Chemistry 2012