Population genomic structure of the gelatinous zooplankton species Mnemiopsis leidyi in its nonindigenous range in the North Sea

Nonindigenous species pose a major threat for coastal and estuarine ecosystems. Risk management requires genetic information to establish appropriate management units and infer introduction and dispersal routes. We investigated one of the most successful marine invaders, the ctenophore Mnemiopsis leidyi, and used genotyping-by-sequencing (GBS) to explore the spatial population structure in its nonindigenous range in the North Sea. We analyzed 140 specimens collected in different environments, including coastal and estuarine areas, and ports along the coast. Single nucleotide polymorphisms (SNPs) were called in approximately 40 k GBS loci. Population structure based on the neutral SNP panel was significant (F-ST .02; p < .01), and a distinct genetic cluster was identified in a port along the Belgian coast (Ostend port; pairwise F-ST .02-.04; p < .01). Remarkably, no population structure was detected between geographically distant regions in the North Sea (the Southern part of the North Sea vs. the Kattegat/Skagerrak region), which indicates substantial gene flow at this geographical scale and recent population expansion of nonindigenous M. leidyi. Additionally, seven specimens collected at one location in the indigenous range (Chesapeake Bay, USA) were highly differentiated from the North Sea populations (pairwise F-ST .36-.39; p < .01). This study demonstrates the utility of GBS to investigate fine-scale population structure of gelatinous zooplankton species and shows high population connectivity among nonindigenous populations of this recently introduced species in the North Sea. OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at: The DNA sequences generated for this study are deposited in the NCBI sequence read archive under SRA accession numbers -, and will be made publically available upon publication of this manuscript

Effekter av kongekrabben på økosystemet på bløtbunn: undersøkelser i Varanger 2006-2009

Kongekrabben er en fremmed art som har spredd seg til kysten av Finnmark etter utsetting i Russland på 1960-tallet. I Varangerområdet har krabben hatt en høy bestand siden midten av 1990-tallet. Kongekrabben er et aktivt rovdyr som tar et bredt utvalg av bunnorganismer som føde. Voksne individer lever store deler av året på bløtbunn på dypere vann (100-400 m) hvor de synes å hente sin hovednæring. Denne rapporten gir en sammenfatning av undersøkelser i Varanger i perioden 2006-2009 som belyser hvordan bunnfauna og økosystemet på bløtbunn påvirkes av kongekrabben. Prøvetakingen er foretatt med krabbetrål, hvor bifangst av andre arter enn kongekrabben er registrert, bunnskraper og bunngrabb. Prøvene med bunngrabb omfattet lokaliteter hvor det var foretatt undersøkelser av bunnfauna i 1994 før bestanden av kongekrabben økte sterkt. I tillegg ble det gjort undersøkelser av biologisk aktivitet i bunnsedimentene med sedimentprofilfotografering (SPI). Undersøkelsene har vist: · Mange vanlig forekommende arter av bunndyr på bløtbunn er markert redusert i områder med mye kongekrabbe. Rent spesifikt synes alle større organismer med liten bevegelsesevne slik som pigghuder, gravende børstemark og større muslinger å være sterkt redusert eller helt borte. · Noen få svært små arter av rørbyggende børstemark og muslinger har blitt mer tallrike. Økologisk fører dette til at bunndyrsamfunnet endrer karakter og blir dominert av noen få arter. · Endringene i bunndyrsamfunnet har konsekvenser for økologiske prosesser i bunnsedimentet. Spesielt synes det som om aktiviteter som driver vanntransport i sedimentet og derved transport av oksygen til dypere sedimentlag reduseres. Dette rammer igjen normale stoffomsetningsprosesser nede i bunnsedimentet. I enkelte områder var det lokalt betydelig nedsatt sedimentkvalitet. Konsekvensene er at færre ”økosystemtjenester” i bunnmiljøet blir utført. · Endringene i bunndyrsamfunnet er langt større enn hva som kan forventes ved naturlig variasjon. Faktisk er endringene på nivå med det som kjennes fra markert forurensning eller kraftig overgjødsling hvor mange arter går sterkt tilbake. I Varanger kjenner vi ikke til andre faktorer enn beitepress fra kongekrabben som vil kunne føre til så omfattende endringer i de undersøkte områdene. Undersøkelsene kan ikke vise hvor utbredt effektene er. Nedsatt sedimentkvalitet ble påvist der det var lokalt høye tettheter av krabben, mens det i andre områder var gode forhold. Det må derfor forventes å være betydelige geografiske variasjoner. Spørsmål som melder seg er hva som kan skje i tilfeller der andre former for miljøpåvirkning kan komme i tillegg. Slike påvirkninger kan være utslipp av organisk materiale, forurensning av miljøgifter, fysisk forstyrrelse fra bunntråling eller oljesøl. Det er også et uavklart spørsmål i hvilken grad bunndyrsamfunnet vil kunne vende tilbake mot normal tilstand dersom bestanden av kongekrabben reduseres.Direktoratet for naturforvaltning, eni Norge og Sydvaranger Gruv

Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2016

The Regional Coordination Meeting NS&EA met in Edinburgh from 5th to 9th September 2016. Thirty four participants from 12 members states, representatives from Commission and ICES were in attendance. The meeting was largely devoted to subgroup work relating to regional sampling, cost sharing models, data needs and the sampling of anadromous and catadromous specie

Ocean current connectivity propelling the secondary spread of a marine invasive comb jelly across western Eurasia

Publication history: Accepted - 15 February 2018; Published - 16 May 2018.Aim: Invasive species are of increasing global concern. Nevertheless, the mechanisms driving further distribution after the initial establishment of non-native species remain largely unresolved, especially in marine systems. Ocean currents can be a major driver governing range occupancy, but this has not been accounted for in most invasion ecology studies so far. We investigate how well initial establishment areas are interconnected to later occupancy regions to test for the potential role of ocean currents driving secondary spread dynamics in order to infer invasion corridors and the source–sink dynamics of a non-native holoplanktonic biological probe species on a continental scale. Location: Western Eurasia. Time period: 1980s–2016. Major taxa studied: ‘Comb jelly’ Mnemiopsis leidyi. Methods: Based on 12,400 geo-referenced occurrence data, we reconstruct the invasion history of M. leidyi in western Eurasia. We model ocean currents and calculate their stability to match the temporal and spatial spread dynamics with large-scale connectivity patterns via ocean currents. Additionally, genetic markers are used to test the predicted connectivity between subpopulations. Results: Ocean currents can explain secondary spread dynamics, matching observed range expansions and the timing of first occurrence of our holoplanktonic non-native biological probe species, leading to invasion corridors in western Eurasia. In northern Europe, regional extinctions after cold winters were followed by rapid recolonizations at a speed of up to 2,000 km per season. Source areas hosting year-round populations in highly interconnected regions can re-seed genotypes over large distances after local extinctions. Main conclusions: Although the release of ballast water from container ships may contribute to the dispersal of non-native species, our results highlight the importance of ocean currents driving secondary spread dynamics. Highly interconnected areas hosting invasive species are crucial for secondary spread dynamics on a continental scale. Invasion risk assessments should consider large-scale connectivity patterns and the potential source regions of non-native marine species.Danish Council for Independent Research; Grant/Award Number: DFF-1325-00102B; FP7 People: Marie-Curie Actions, Grant/Award Number: MOBILEX, DFF - 1325-00025; EU, BONUS, BMBF, Grant/ Award Number: 03F0682; Excellence Cluster “Future Ocean”, Grant/Award Number: CP153

Workshop on Raising Data using the RDBES and TAF (WKRDBESRaiseTAF; outputs from 2022 meeting)

41 páginasThe Workshop on Raising Data using the RDBES and TAF (WKRDBES-Raise&TAF) met online (26–30 of September 2022) to evaluate the use of the Regional Database and Estimation System (RDBES) format to reproduce the 2022 InterCatch input and output, identifying a Transparent Assessment Framework (TAF) structure to organize the intermediate steps and to propose standardized output formats. The main outcomes of WKRDBES-Raise&TAF were: · RDBES provides sufficient support for current national estimation protocols. However, some minor issues were reported that hampered an exact reproduction of the estimates. Therefore, adaptations of the data model should not be excluded completely. · All the input to stock assessment that InterCatch currently provides, could be reproduced. The participants started from the current stock extracts that can be downloaded from InterCatch. · A workflow was proposed with a national TAF repository for each country, a stock estimation repository and a stock assessment repository. The intermediate output of those repositories will be stored in an ‘intermediate output database’ and depending on the user role, you will get access to the relevant stages in this workflow. · The following requirements for the standard output formats were defined: they cannot be more restrictive than the InterCatch input and output format; they should present measures of uncertainty and sample sizes (for national estimates) and should have a configurable domain definition (for national estimates). Despite those successful outcomes, the current plan for transition to an operational system was concluded to be too optimistic. WKRDBES-Raise&TAF therefore recommends to the Working Group on Governance of the Regional Database and Estimation System (WGRDBESGOV) to revise the roadmap and allow RDBES to be in a test phase also for 2023. WKRDBES-Raise&TAF felt the need to test the proposed workflow on a small scale and therefore recommends to the WGRDBESGOV to arrange a workshop where two stocks (pok.27.3a46 (Saithe (Pollachius virens) in Subareas 4, 6 and Division 3.a (North Sea, Rockall and West of Scotland, Skagerrak and Kattegat) and wit.27.3a47d (Witch (Glyptocephalus cynoglossus) in Subarea 4 and Divisions 3.a and 7.d (North Sea, Skagerrak and Kattegat, eastern English Channel)) will be set up to go through the whole flow.Peer reviewe

On the distribution and population dynamics of the ctenophore Mnemiopsis leidyi in the Belgian part of the North Sea and Westerschelde estuary

A

Scat analysis reveals a wide set of plant species to be potentially dispersed by foxes

Background and aims A good understanding of the ways in which seeds are dispersed within landscapes is essential to plant ecology and conservation. Carnivorous mammals can act as vectors in dispersal through ingestion and subsequent excretion of seeds (endozoochory). The red fox (Vulpes vulpes L.) is a predatory species that is markedly opportunistic both in habitat and feeding habits, and occurs widespread in many rural and urbanized regions. Due to their high mobility within and among territories, they could contribute to long-distance seed dispersal on a regular basis. To identify the set of species that are potentially dispersed by foxes, we have analyzed scats from the region of Flanders (Belgium) for seeds. Methods 303 scats were collected throughout the region during two field campaigns. All seeds were isolated from the scats and identified. Key results Seeds were present in 57% of the scats. If present, the seed number was mostly low (< 10), yet amounted to 1135 in one sample. 77 taxa were identified. 82% of the seeds belonged to woody plant species with fleshy propagules (drupes or berries), Rubus being the most abundant taxon (64%). In addition, numerous dry-fruited woody, herbaceous, and graminoid taxa were found. Autumn samples contained more, and more often, seeds than spring samples. Conclusions The diversity of plant types and species encountered in scats clearly reflects the opportunistic habits of foxes, with many species consumed from anthropogenic sources such as cultivated plants or waste material. We suspect an inadvertent intake for most of the dry-fruited species, for instance, through the manipulation of prey. Although wild foxes thus appear to excrete a diverse set of species, their role as effective seed dispersers needs further investigation, primarily concerning the fate of these scat-borne seeds