The sardine run in southeastern Africa is a mass migration into an ecological trap

Teske, Peter R.; Emami‐Khoyi, Arsalan; Golla, Tirupathi Rao; Sandoval‐Castillo, Jonathan; Lamont, Tarron; Chiazzari, Brent; McQuaid, Christopher D.; Beheregaray, Luciano B.; Lingen, CD van der

doi:10.1126/sciadv.abf4514

Cited by 17 publications

(10 citation statements)

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“…The South African coastline encompasses a large variety of ecosystems, including rocky and sandy shores, kelp forests, estuaries and coral reefs, as well as contrasting environmental conditions (Branch & Branch, 2018) that drive high levels of coastal marine biodiversity. Four major phylogeographic breaks have been identified, and most coastal species, including organisms with high dispersal capacities, are divided into genetic lineages whose distributional ranges broadly match the bioregions (Figure 1; Teske et al, 2011; Wright et al, 2015), with evidence for temperature and salinity as important drivers of potential local adaptation (Nielsen et al, 2020; Phair et al, 2019; Teske et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

Dalongeville

Nielsen

Teske

et al. 2022

Diversity and Distributions

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Aim: Intraspecific genetic variation is a key component of biodiversity, with higher diversity indicating greater resilience and population substructuring suggesting unique evolutionary histories. Comparative approaches, in which intraspecific genetic variation is assessed across multiple species, are powerful tools to identify evolutionary hotspots, but are still rarely applied at spatial scales relevant to conservation planning.Here, we use comparative phylogeography to understand patterns and potential drivers of genetic variation within a biodiversity and ocean warming hotspot. Location:The South African coastline, Indian/Atlantic Oceans. Methods:A literature search was conducted to obtain mitochondrial DNA cytochrome oxidase c subunit I and cytochrome b sequence data for 17 marine fish and invertebrate species. From these data, we compared averages of haplotype and nucleotide diversity, and within-region Φ ST between four biogeographic provinces in the region.Mixed linear models tested whether environmental variability, habitat preference, or geographic location significantly influence genetic variation. Results:Average diversity values differed between haplotype and nucleotide diversity, but both broadly displayed highest diversity levels within the South-West bioregion, which is also a region of high levels of within-region Φ ST . Range in sea surface temperatures (SSTs) was the only significant fixed-effect term in the haplotype diversity mixed linear models. Mean SST, stability in SSTs since the Mid-Holocene and position within the species' geographic distribution all had no significant effect on genetic variation. Main conclusions:Along this coastline characterized by high environmental heterogeneity, we find that variation in temperature is a prominent source of intraspecific variation. Genetic diversity differs between bioregions, but does not display higher levels within the core of each species' range when assessed across multiple species. With elevated levels of genetic diversity, the South-West region of the South African coast is highlighted as a conservation priority area, representing both high genetic diversity and differentiation across taxa.

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Section: Introductionmentioning

confidence: 99%

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

Dalongeville

Nielsen

Teske

et al. 2022

Diversity and Distributions

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“…The two clusters could be detected even with the use of only 196 outlier SNPs linking candidate SNPs to the region's environmental heterogeneity, as seen in other sardine species (Teske et al, 2021). In contrast, when only putatively neutral SNPs were used (i.e., 3002 SNPs), detection of any pattern of population structure failed, suggesting that natural selection and local adaptation play a key role in driving genetic change (Metivier et al, 2017) among the Atlantic and the Mediterranean Sea.…”

Section: Discussionmentioning

confidence: 96%

“…The two clusters could be detected even with the use of only 196 outlier SNPs linking candidate SNPs to the region's environmental heterogeneity as seen in other sardine species (Teske et al, 2021). In contrast, when only putatively neutral SNPs were used (i.e.…”

Section: Understanding the Population Structure Of Sardinesmentioning

confidence: 92%

Sardines at a junction: Seascape genomics reveals ecological and oceanographic drivers of variation in the NW Mediterranean Sea

et al. 2023

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By evaluating genetic variation across the entire genome, one can address existing questions in a novel way while raising new ones. The latter include how different local environments influence adaptive and neutral genomic variation within and among populations, providing insights into local adaptation of natural populations and their responses to global change. Here, under a seascape genomic approach, ddRAD data of 4609 SNPs from 398 sardines (Sardina pilchardus) collected in 11 Mediterranean and one Atlantic site were generated. These were used along with oceanographic and ecological information to detect signals of adaptive divergence with gene flow across environmental gradients. The studied sardines constitute two clusters (FST=0.07), a pattern attributed to outlier loci, highlighting putative local adaptation. The trend in the number of days with sea surface temperature above 19oC, critical threshold Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.for successful sardine spawning, was crucial at all levels of population structuring with implications on species' key biological processes. Outliers link candidate SNPs to the region's environmental heterogeneity. Our findings provide evidence for a dynamic equilibrium where population structure is maintained by physical and ecological factors under the opposing influences of migration and selection. This dynamic in nature system, warrants continuous monitoring under a seascape genomic approach that might benefit from a temporal and more detailed spatial dimension. Our results may contribute to complementary studies aimed at providing deeper insights into the mechanistic processes underlying population structuring. Those are key for understanding and predicting future changes and responses of this highly exploited species in the face of climate change.

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“…Migration is a common strategy of pelagic species to cope with seasonal variation of resources at both small and large geographic scales (Angel, 1993). Small pelagic fishes (clupeids, mackerels) are known for their schooling behaviour and large distribution ranges often linked to their long-distance migrations (Teske et al, 2021). Therefore, small pelagic fishes have been proposed as indicator taxa for ecosystem changes related to e.g., climate change and overfishing.…”

Section: Trophic and Host-parasite Interactions In Pelagic Systemsmentioning

confidence: 99%

Host lifestyle and parasite interspecific facilitation mediate co-infection in a species-poor host-parasite system

Kmentová

Cruz-Laufer

Milec

et al. 2023

Preprint

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Pelagic zones are characterised by consistent large-scale patterns of circulation on local and global scales. Lake Tanganyika, as an enclosed ecosystem provides a playing field to study evolutionary and ecological processes applicable to open water areas worldwide. Despite their important role in the ecosystem, large scale patterns of the distribution of parasites remain poorly understood. Monogenean parasites have been proposed as tags for ecosystem dynamics because of their direct life cycle and often high host specificity. We combined data on spatiotemporal dynamics of parasites (Kapentagyrus, Monogenea) with morphological variation of clupeid hosts to investigate general patterns of host-parasite interactions in the pelagic zone of this ancient lake. Two dominant species of clupeid fishes in the pelagic zone of Lake Tanganyika are parasitised by two monogenean species of Kapentagyrus with different levels of host specificity. The host fishes are believed to perform lake-wide migrations driven by seasonal upwellings. To model spatiotemporal dynamics of host-parasite interaction, we used temporal data on monogenean infection along the North-South axis of Lake Tanganyika based on 1730 screened fishes and 3710 parasites together with phenotypic characterisation of the clupeid hosts. Infection levels are dependent on host body size with contrasting trends in the two parasite species. We reveal temporal stability of infection with spatial distribution restricted by host life strategies. Spatial differences between the parasite species most likely reflect differences in migration between the host species; these are also reflected by morphological differences between some clupeid populations. Our results also suggest mutual facilitation of infection. In conclusion, parasite infection is geographically restricted by host life strategies even in this ecosystem lacking physical barriers. Intensity of infection seems to be mainly driven by host size, with so far rarely reported mutual facilitation of co-infection. Temporal stability of infection in the pelagic zone contrasts with seasonal changes in abundance of clupeid hosts. Overall, our results suggest that parasite infection dynamics in the open water areas are dependent on life style and not host density.

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The sardine run in southeastern Africa is a mass migration into an ecological trap

Cited by 17 publications

References 72 publications

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

Sardines at a junction: Seascape genomics reveals ecological and oceanographic drivers of variation in the NW Mediterranean Sea

Host lifestyle and parasite interspecific facilitation mediate co-infection in a species-poor host-parasite system

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