North Sea Houting Research Articles

Genomic insights on conservation priorities for North Sea houting and European lake whitefish (Coregonus spp.).

Population genomics analysis holds great potential for informing conservation of endangered populations. We focused on a controversial case of European whitefish (Coregonus spp.) populations. The endangered North Sea houting is the only coregonid fish that tolerates oceanic salinities and was previously considered a species (C. oxyrhinchus) distinct from European lake whitefish (C. lavaretus). However, no firm evidence for genetic-based salinity adaptation has been available. Also, studies based on microsatellite and mitogenome data suggested surprisingly recent divergence (c. 2500 years bp) between houting and lake whitefish. These data types furthermore have provided no evidence for possible inbreeding. Finally, a controversial taxonomic revision recently classified all whitefish in the region as C. maraena, calling conservation priorities of houting into question. We used whole-genome and ddRAD sequencing to analyse six lake whitefish populations and the only extant indigenous houting population. Demographic inference indicated post-glacial expansion and divergence between lake whitefish and houting occurring not long after the Last Glaciation, implying deeper population histories than previous analyses. Runs of homozygosity analysis suggested not only high inbreeding (FROH up to 30.6%) in some freshwater populations but also FROH up to 10.6% in the houting prompting conservation concerns. Finally, outlier scans provided evidence for adaptation to high salinities in the houting. Applying a framework for defining conservation units based on current and historical reproductive isolation and adaptive divergence led us to recommend that the houting be treated as a separate conservation unit regardless of species status. In total, the results underscore the potential of genomics to inform conservation practices, in this case clarifying conservation units and highlighting populations of concern.

Investigating fish migration, mortality, and physiology to improve conservation planning of anadromous salmonids: a case study on the endangered North Sea houting (Coregonus oxyrinchus)

Understanding migratory behavior, mortality, and physiology is essential for conservation of many species, particularly anadromous fish. In this study, freshwater and marine migrations of the endangered salmonid North Sea houting (Coregonus oxyrinchus (Linnaeus, 1758)) were investigated using telemetry. Furthermore, physiological samples were collected from North Sea houting and from resident and anadromous populations of the closely related European whitefish (Coregonus lavaretus (Linnaeus, 1758)) to compare hypo-osmotic tolerances. On average, North Sea houting spent 193 days at sea where the mortality was 36%. Most fish returned from sea in the autumn, and river entry correlated inversely with river temperature and positively with discharge. Fish spent an average of 49 days in the estuarine area. Artificial lakes negatively affected migration speeds. Migration speeds did not differ consistently between individuals (i.e., not a repeatable trait) but correlated positively with water temperature. Fish arrived at spawning areas in November. In the post-spawning state, Na+/K+-ATPase activities were elevated in North Sea houting and anadromous whitefish compared with resident whitefish, while osmolality was elevated only in North Sea houting. Our study provides important information for conservation planning related to the Habitat Directive of the European Union that lists the North Sea houting as critically endangered.

Evidence of cormorant‐induced mortality, disparate migration strategies and repeatable circadian rhythm in the endangered North Sea houting (Coregonus oxyrinchus): A telemetry study mapping the postspawning migration

AbstractLife history theory predicts a trade‐off between migration and residency where migration is favoured when it infers elevated fitness. Although migration to more favourable environments may offer higher growth rates, migrants often experience increased mortality due to predation. Here, we investigated mortality and migration behaviour of the North Sea houting (Coregonus oxyrinchus), an anadromous salmonid endemic to the Wadden Sea. We used acoustic telemetry to map the migration of the only remaining indigenous population by applying stationary hydrophones combined with manual tracking. Data suggested a total mortality of 26%, with 30% of the total mortality attributed to predation by great cormorants (Phalacrocorax carbo sinensis), highlighting that North Sea houting conservation could be jeopardised by increased cormorant predation. Risk of cormorant predation was size‐dependent, with smaller fish suffering higher risk of predation. The study found North Sea houting to exhibit disparate migration strategies and identified a lentic area in the estuary as an important habitat. Two newly established artificial lakes within the river system significantly reduced the migration speeds, possibly indicating constrained navigation through the lakes. The migration into the Wadden Sea correlated with temperature perhaps indicating osmoregulatory constraints of sea entry. Unlike many salmonid species, migration occurred both day and night. Moreover, fish exhibited repeatable individual differences in diel activity patterns, suggesting that individuals differ consistently in their migratory activity throughout the 24‐hr period. Our study provides novel information on salmonid migration, which is crucial for the development of science‐based conservation strategies.

Development of salinity tolerance in the endangered anadromous North Sea houting Coregonus oxyrinchus: implications for conservation measures

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 28:175-186 (2015) - DOI: https://doi.org/10.3354/esr00692 Development of salinity tolerance in the endangered anadromous North Sea houting Coregonus oxyrinchus: implications for conservation measures Lasse Fast Jensen1,*, Dennis Søndergård Thomsen2, Steffen S. Madsen3, Mads Ejbye-Ernst4, Søren Brandt Poulsen5, Jon C. Svendsen1,6 1Fisheries and Maritime Museum, Tarphagevej 2, 6710 Esbjerg V, Denmark 2Ramboll Denmark, Englandsgade 25, 5000 Odense C, Denmark 3Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark 4The Danish Nature Agency, Skovridervej 3, 6510 Gram, Denmark 5Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus C, Denmark 6Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal *Corresponding author: lfj@fimus.dk ABSTRACT: The North Sea houting Coregonus oxyrinchus is an endangered anadromous salmonid belonging to the European lake whitefish complex. The last remaining indigenous population of North Sea houting is found in the River Vidaa, Denmark. Despite legislative protection and numerous stocking and habitat restoration programmes, including a € 13.4 million EU Life restoration project, populations are declining in most rivers in Denmark. Limited knowledge of the general biology of the species, in particular of the early life history stages and habitat requirements, is a serious impediment to management and conservation. In this study, we investigated larval and juvenile salinity tolerance, providing novel information on the early life stages of North Sea houting. Results revealed an ontogenetic differentiation in salinity tolerance when comparing newly hatched larvae, larvae at later developmental stages and juveniles expected to initiate migration to the Wadden Sea. At all developmental stages, larvae exhibited poor hyperosmotic tolerance, while juveniles performed significantly better. Larvae suffered from high mortality and loss of body water at salinities of 18 ppt and higher, while most juveniles survived 30 ppt at least when exposed to gradually increasing salinities. Our results suggest that larval North Sea houting experience very high mortality if carried directly into the Wadden Sea prematurely, highlighting the need for suitable habitat within rivers to retain larvae. Our study shows how different life stages respond differently to varying environmental conditions and emphasizes the need for understanding the physiological mechanisms to improve conservation of endangered species. KEY WORDS: Anadromous · Conservation · Coregonus oxyrinchus · Habitat restoration · North Sea houting · Ontogeny · Osmoregulation · Salinity tolerance · Whitefish Full text in pdf format Supplementary material PreviousCite this article as: Jensen LF, Thomsen DS, Madsen SS, Ejbye-Ernst M, Poulsen SB, Svendsen JC (2015) Development of salinity tolerance in the endangered anadromous North Sea houting Coregonus oxyrinchus: implications for conservation measures. Endang Species Res 28:175-186. https://doi.org/10.3354/esr00692 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 28, No. 2. Online publication date: September 10, 2015 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2015 Inter-Research.

Anthropogenic hybridization between endangered migratory and commercially harvested stationary whitefish taxa (Coregonus spp.).

Natural hybridization plays a key role in the process of speciation. However, anthropogenic (human induced) hybridization of historically isolated taxa raises conservation issues. Due to weak barriers to gene flow and the presence of endangered taxa, the whitefish species complex is an excellent study system to investigate the consequences of hybridization in conservation. We focused on three naturally reproductively isolated whitefish taxa in Germany: the endangered, anadromous North Sea houting (NSH) and Baltic houting (BH), which were reintroduced after local extinction, and the commercially stocked European whitefish (EW). To evaluate the genetic integrity of each taxon, source and reintroduced populations of NSH and BH, and EW populations were characterized based on two mitochondrial and 17 microsatellite loci. Additionally, we investigated gill raker counts as an adaptive phenotypic trait. Even though clear genetic and phenotypic differentiation confirmed the houtings as separate evolutionarily significant units, admixture analyses revealed an extensive hybrid zone. Hybridizations were introgressive, positively correlated with genetic diversity, and were reflected in the gill raker counts. The BH distribution range showed higher heterogeneity and stronger admixture than the NSH range. Erroneous stocking with non-native genotypes best explained these patterns, which pose challenges for the conservation of the endangered NSH and BH.

Spawning migration and larval drift of anadromous North Sea houting (Coregonus oxyrinchus) in the River IJssel, the Netherlands

AbstractAnadromous North Sea houting (NSH, Coregonus oxyrinchus) was historically distributed in the Wadden Sea extending from Jutland (Denmark) to the Schelde delta (Netherlands). The species has been considered extinct in the Rhine since the 1940s; however, a successful re‐introduction programme re‐established a self‐reproducing population. Telemetry data of adult NSH (NEDAP TRAIL System®) were used for a first description of the timing of spawning migrations of NSH in winter, but also suggested that the River IJssel, a lower branch of the Rhine, may serve as spawning ground. This was further proven in spring 2010 with drift net catches of 218 freshly hatched NSH larvae sampled directly upstream from Kampen, where the IJssel discharges into Lake IJsselmeer. These larvae did not differ between controls from a hatchery that were about 12 h of age, indicating that the drifting larvae of NSH must have hatched in upstream areas of the River IJssel.

Ontogenetic differentiation of swimming performance and behaviour in relation to habitat availability in the endangered North Sea houting (Coregonus oxyrinchus)

The survival of the highly endangered, anadromous fish species North Sea houting (Coregonus oxyrinchus) depends on the correct timing of downstream dispersal during its early ontogenetic stages. To date, however, no studies have investigated the ontogenetic differentiation of swimming performance and behaviour, including the potential of habitat complexity to influence dispersal rates. By testing larval and juvenile North Sea houting in a laboratory, we examined (1) swimming performance measured as maximum swimming performance (Umax) and routine swimming speed (Uroutine) and (2) the potential of habitat complexity (i.e., cover providing shade) to influence dispersal behaviour in an indoor stream channel. The Umax and the Uroutine were 9.4 and 4.6cm s-1, respectively, in the larvae [body length (BL) s-1: 7.3 and 3.5, respectively], and 25.2 and 16.3 cm s-1 in the juveniles (BL s-1: 7.0 and 5.2, respectively). We compared laboratory swimming performance data with water speeds in North Sea houting spawning areas in the Danish River Vidaa. Results showed that the water speeds present in 95% and 85% of the water column caused downstream displacement of larvae and juveniles, respectively. However, areas with slow-flowing water near river banks and river beds could function as nursery habitats. Stream channel experiments showed that cover providing shade caused delayed dispersal in both larvae and juveniles, but the larvae dispersed later and spent less time under cover than the juveniles, a finding that implies ontogenetic effects. Finally, the larvae refused to cross an upstream-positioned cover, a behaviour that was not observed in the juveniles. Therefore, habitat complexity may have the potential to influence dispersal behaviour in both larval and juvenile North Sea houting. Overall, we provided the first evidence of ontogenetic differentiation in the North Sea houting. These findings will be valuable for the development and dissemination of science-based conservation strategies.

Mitogenome sequencing reveals shallow evolutionary histories and recent divergence time between morphologically and ecologically distinct European whitefish (Coregonus spp.)

The advent of second-generation sequencing has made it possible to quickly and economically generate whole mitochondrial genome (mitogenome) sequences. To date, mitogenome studies of nonmodel organisms have demonstrated increased power for resolving interspecies relationships. We explored an alternate use of such data to recover relationships and population history of closely related lineages with a shallow evolutionary history. Using a GS-FLX platform, we sequenced 106 mitogenomes from the Coregonus lavaretus (Europe) and Coregonus clupeaformis (North America) species complexes to investigate the evolutionary history of the endangered Danish North Sea houting (NSH) and other closely related Danish and Baltic European lake whitefish (ELW). Two well-supported clades were found within both ELW and NSH, probably reflecting historical introgression via Baltic migrants. Although ELW and NSH are not reciprocally monophyletic, they share no haplotypes, suggesting recent, but strong, reproductive isolation. The divergence time between NSH and the geographically closest ELW population was estimated using IMa, assuming isolation with migration and a new mutation rate estimate chosen to avoid time-dependency effects. The estimate of c. 2700 bp was remarkably similar to results obtained using microsatellite markers. Within North American C. clupeaformis, the divergence time between the two lineages (Atlantic and Acadian) was estimated as between 20,000 and 60,000 bp. Under the assumption that NSH and ELW colonized Denmark following the last glacial maximum, Bayesian Serial SimCoal analysis showed consistency with a scenario of long-term stability, resulting from a rapid initial sixfold population expansion. The findings illustrate the utility of mitogenome data for resolving recent intraspecific divergence events and provide evidence for recent reproductive isolation of the phenotypically divergent NSH.

Decline of the North Sea houting: and protective measures for an endangered anadromous fish

Once an abundant fish species in the rivers of the Wadden Sea in northwest Europe, the North Sea houting Coregonus oxyrinchus (NSH) was at the brink of extinction 25 yr ago. The very last stronghold for this species was in the small Danish River Vidaa. In an attempt to preserve this anadromous whitefish species, juveniles were hatchery-reared and stocked in 6 Danish rivers flowing into the Wadden Sea. These stocking efforts were fairly successful, and the houting estab- lished populations in at least 2 of the rivers, but the underlying problem of habitat degradation and migration obstacles was not solved. Since a national management plan was issued in Denmark in 2003, large-scale river restoration measures have been undertaken, including the removal of 13 large obstacles in 3 NSH rivers and reestablishment of meanders in the lower river reaches. These measures were all intended to increase the spawning area for NSH and reduce juvenile mortality of NSH. The generic effect of these recent and ongoing changes is, however, not yet known. The NSH population has been irregularly monitored under various programs. Results from 15 yr of field investigation using passive integrated transponder (PIT)-tagging showed that the NSH pop- ulation in the River Vidaa remains stable, but in the other 2 rivers populations are decreasing. However, due to the recent physical improvements in river habitat and connectivity, we expect a substantial improvement in the population status of the NSH in the near future. Once they reach sexual maturity, NSH grow relatively slowly (mean: 2.55 cm yr �1 , ranging from 0 to 13.8 cm yr �1 ) and can reach an age of 10 to 12 yr. The number of repeated recaptures year after year indicates low mortality for adult fish. Six individuals were recaptured in rivers other than the one in which they were initially PIT-tagged, indicating some exchange/straying between adjacent rivers. Over- all there is a good chance that this unique species was saved in the 11th hour by intervention from managers and the EU.

Effects of food deprivation on refuge use and dispersal in juvenile North Sea houting Coregonus oxyrinchus under experimental conditions

This study tested the influence of energetic state on refuge use and dispersal in juvenile North Sea houting Coregonus oxyrinchus in an artificial stream. Food-deprived fish spent more time outside refuges than well-fed fish; however, the well-fed fish initiated dispersal faster than the food-deprived fish. The results may indicate state-dependent refuge use and dispersal in C. oxyrinchus.

Re‐establishment of the North Sea houting in the River Rhine

Fisheries Management and EcologyVolume 17, Issue 3 p. 291-293 Re-establishment of the North Sea houting in the River Rhine J. BORCHERDING, J. BORCHERDINGSearch for more papers by this authorM. HEYNEN, M. HEYNENSearch for more papers by this authorT. JÄGER-KLEINICKE, T. JÄGER-KLEINICKESearch for more papers by this authorH. V. WINTER, H. V. WINTERSearch for more papers by this authorR. ECKMANN, R. ECKMANNSearch for more papers by this author J. BORCHERDING, J. BORCHERDINGSearch for more papers by this authorM. HEYNEN, M. HEYNENSearch for more papers by this authorT. JÄGER-KLEINICKE, T. JÄGER-KLEINICKESearch for more papers by this authorH. V. WINTER, H. V. WINTERSearch for more papers by this authorR. ECKMANN, R. ECKMANNSearch for more papers by this author First published: 07 May 2010 https://doi.org/10.1111/j.1365-2400.2009.00710.xCitations: 12 Jost Borcherding, University of Cologne Zoological Institute, General Ecology and Limnology, Research Station Grietherbusch, D-46459 Rees-Grietherbusch, Germany (e-mail: jost.borcherding@uni-koeln.de) Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume17, Issue3June 2010Pages 291-293 RelatedInformation

Migration history of North Sea houting (Coregonus oxyrinchus L.) caught in Lake IJsselmeer (The Netherlands) inferred from scale transects of 88Sr:44Ca ratios

North Sea houting, Coregonus oxyrinchus, became extinct in the River Rhine in the 1940 s and was reintroduced in the 1990 s. To study the migration history of individuals, the 88Sr:44Ca ratio of scales of 39 houting (10–44 cm TL) caught in Lake IJsselmeer was analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Scales of houting inhabiting freshwater ponds and two Danish rivers containing the last original populations in the North Sea basin were used as controls. Fish that lived exclusively in freshwater had 88Sr:44Ca ratios of around 0.2 from the nucleus to the edge; 29 of the analysed houting from Lake IJsselmeer were of this type. Most of these were small, but some were mature and up to 42 cm in length. Seven houting had 88Sr:44Ca ratios over 0.27 from the nucleus to the scale maximum values, indicating migration to the sea at early life stages. Three houting with low 88Sr:44Ca ratios at the scale nucleus and increased 88Sr:44Ca ratios towards the scale edge probably lived in freshwater for a longer period after hatching and then moved to brackish/marine environments. The scale analysis indicates different migration patterns for houting in Lake IJsselmeer and provides evidence that this species (1) is sometimes able to pass the migratory barriers between the Wadden Sea and Lake IJsselmeer, and (2) does not need to migrate to sea to reach maturity.

Reproductive isolation, evolutionary distinctiveness and setting conservation priorities: The case of European lake whitefish and the endangered North Sea houting (Coregonus spp.)

BackgroundAdaptive radiation within fishes of the Coregonus lavaretus complex has created numerous morphs, posing significant challenges for taxonomy and conservation priorities. The highly endangered North Sea houting (C. oxyrhynchus; abbreviated NSH) has been considered a separate species from European lake whitefish (C. lavaretus; abbreviated ELW) due to morphological divergence and adaptation to oceanic salinities. However, its evolutionary and taxonomic status is controversial. We analysed microsatellite DNA polymorphism in nine populations from the Jutland Peninsula and the Baltic Sea, representing NSH (three populations, two of which are reintroduced) and ELW (six populations). The objectives were to: 1) analyse postglacial recolonization of whitefish in the region; 2) assess the evolutionary distinctiveness of NSH, and 3) apply several approaches for defining conservation units towards setting conservation priorities for NSH.ResultsBayesian cluster analyses of genetic differentiation identified four major groups, corresponding to NSH and three groups of ELW (Western Jutland, Central Jutland, Baltic Sea). Estimates of historical migration rates indicated recolonization in a north-eastern direction, suggesting that all except the Baltic Sea population predominantly represent postglacial recolonization via the ancient Elbe River. Contemporary gene flow has not occurred between NSH and ELW, with a divergence time within the last 4,000 years suggested from coalescence methods. NSH showed interbreeding with ELW when brought into contact by stocking. Thus, reproductive isolation of NSH was not absolute, although possible interbreeding beyond the F1 level could not be resolved.ConclusionFishes of the C. lavaretus complex in the Jutland Peninsula originate from the same recolonization event. NSH has evolved recently and its species status may be questioned due to incomplete reproductive isolation from ELW, but it was shown to merit consideration as an independent conservation unit. Yet, application of several approaches for defining conservation units generated mixed outcomes regarding its conservation priority. Within the total species complex, it remains one among many recently evolved unique forms. Its uniqueness and high conservation priority is more evident at a local geographical scale, where conservation efforts will also benefit populations of a number of other endangered species.

Timing of downstream migration and food uptake of juvenile North Sea houting stocked in the Lower Rhine and the Lippe (Germany)

In 1992 a stocking programme was established to re‐introduce North Sea houting Coregonus oxyrinchus, which disappeared from the River Rhine in the 1940s, in the Lower Rhine. Juvenile North Sea houting have been stocked since 2001 in a gravel pit lake permanently connected to the Lower Rhine, and in the Lippe, a potamal tributary of the Rhine. Monitoring studies showed that the majority of the small North Sea houting left the gravel pit lake within 4 days after stocking. In the Lippe, some of the juveniles were found in the drift immediately after stocking, generally preferring the middle surface areas of the river. Other North Sea houting waited until dawn before they started their downstream migration. Juveniles immediately started to feed on the zooplankton resources in both waters. Pond studies revealed high growth rates of juvenile North Sea houting, ranging from 0·44 to 0·94 mm day−1. This study suggests that the stocking strategies at both waters of the Lower Rhine comply with the requirements of the migration behaviour of juvenile North Sea houting.

Underwater but not out of sight: genetic monitoring of effective population size in the endangered North Sea houting (Coregonus oxyrhynchus)

We analysed 12 microsatellite DNA loci in temporal samples (1980, 1994, and 2002) from the only remaining indigenous population of the North Sea houting (Coregonus oxyrhynchus) in the Vidaa River, Denmark. Using a novel temporal method, we estimated effective population size (Ne) to be 577.4 (90% highest posterior density limits 297.2–3719.8). The same method was used to estimate Neat the beginning and end of the sampled time interval, and the results were indicative of a relatively stable population. In contrast, tests for recent bottlenecks suggested population declines in the 1980 and 1994 samples, possibly reflecting declines prior to 1980 in the total North Sea houting population. To evaluate the usefulness of the two methods for routine genetic monitoring, we simulated population declines corresponding to reproduction by only 20 or 50 parents in 2002. For both simulated samples, the temporal method provided evidence for a population decline, whereas the test for bottlenecks did not suggest population decline. We conclude that the North Sea houting in the Vidaa River is not immediately threatened by inbreeding or loss of evolutionary potential, and the applied temporal method appears very useful for genetic monitoring of effective population size in endangered, isolated fish populations.

Recent increase of North Sea houting and prospects for recolonization in the Netherlands

Two monitoring programmes in estuarine and freshwater systems in the Netherlands both show a recent increase in anadromous North Sea houting Coregonus oxyrhynchus after it disappeared there in the 1940s. Most houting were immature and caught during the feeding season indicating that at present the riverine and estuarine waters in the Netherlands mainly function as a feeding habitat.

Recent increase of North Sea houting and prospects for recolonization in the Netherlands

Recent increase of North Sea houting and prospects for recolonization in the Netherlands

Postglacial recolonization patterns and genetic relationships among whitefish (Coregonus sp.) populations in Denmark, inferred from mitochondrial DNA and microsatellite markers

The genetic relationships among morphologically and geographically divergent populations of whitefish (genus: Coregonus) from Denmark and the Baltic Sea region were studied by analysis of microsatellites and polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis of mitochondrial DNA (mtDNA) segments. The endangered North Sea houting (classified as C. oxyrhynchus) differs morphologically and physiologically from other Danish whitefish (C. lavaretus). However, limited divergence of North Sea houting was observed both at the level of mtDNA and microsatellites. The implications of these results for the conservation status of North Sea houting are discussed in the light of current definitions of evolutionary significant units. Both mtDNA and microsatellite data indicated that postglacial recolonization by C. lavaretus in Denmark was less likely to have taken place from the Baltic Sea. Instead, the data suggested a recent common origin of all Danish whitefish populations, including North Sea houting, probably by recolonization via the postglacial Elbe River system. Estimates of genetic differentiation among populations based on mtDNA and microsatellites were qualitatively different. In addition, for both classes of markers analyses of genetic differentiation yielded different results, depending on whether molecular distances between alleles or haplotypes were included.