Animal Navigation: The Eel's Magnetic Guide to the Gulf Stream.

The geographic distribution of migratory species can span thousands of kilometers. Yet, traits that enable large-scale migrations are poorly understood. A recent study demonstrates that juvenile eels use the Earth's magnetism for their dispersal, with possible implications for their evolution

Incorporating evolutionary based tools in cephalopod fisheries management

With gradual decline of global finfish resources, fisheries targeting cephalopods expanded. Yet, the stock assessment and management practice are frequently lacking, and existing ones often remain poorly suited for cephalopod unique life-history. In light of increasing ecological disturbances in marine ecosystems worldwide, assessing exploited species’ status and response becomes vital for devising effective strategies that would ensure their sustainable management. There is generally scarce understanding of the way fisheries and other environmental stressors exert their combined effects on cephalopods stock dynamic and long-term resilience. To that end, evolutionary-based population studies that inform on identity, connectivity and adaptive potential of natural populations present a unique opportunity for assessing the viability of exploited cephalopod stocks. Such studies have been revolutionized in the last decade by proliferation of next generation sequencing technologies. They offer new avenues for expanding our knowledge, especially on population structure and the evolutionary responses to shifts in environmental pressures. In this paper we elaborate on how deep genomic insights into demographic and evolutionary status of fished cephalopods could improve their stock assessment and management practice. We also propose that the common octopus Octopus vulgaris would be a suitable model species to test the power of evolutionary tools to inform fishery scientists and managers on biological questions relevant for their sustainable exploitation.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Targeted sequencing of mitochondrial genes reveals signatures of molecular adaptation in a nearly panmictic small pelagic fish species

Ongoing climatic changes, with predictable impacts on marine environmental conditions, are expected to trigger organismal responses. Recent evidence shows that, in some marine species, variation in mitochondrial genes involved in the aerobic conversion of oxygen into ATP at the cellular level correlate with gradients of sea surface temperature and gradients of dissolved oxygen. Here, we investigated the adaptive potential of the European sardine Sardina pilchardus populations offshore the Iberian Peninsula. We performed a seascape genetics approach that consisted of the high throughput sequencing of mitochondria's ATP6, COI, CYTB and ND5 and five microsatellite loci on 96 individuals coupled with environmental information on sea surface temperature and dissolved oxygen across five sampling locations. Results show that, despite sardines forming a nearly panmictic population around Iberian Peninsula, haplotype frequency distribution can be explained by gradients of minimum sea surface temperature and dissolved oxygen. We further identified that the frequencies of the most common CYTB and ATP6 haplotypes negatively correlate with minimum sea surface temperature across the sampled area, suggestive of a signature of selection. With signatures of selection superimposed on highly connected populations, sardines may be able to follow environmental optima and shift their distribution northwards as a response to the increasing sea surface temperatures.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Towards a unified eco-evolutionary framework for fisheries management: Coupling advances in next-generation sequencing with species distribution modelling

The establishment of high-throughput sequencing technologies and subsequent large-scale genomic datasets has flourished across fields of fundamental biological sciences. The introduction of genomic resources in fisheries management has been proposed from multiple angles, ranging from an accurate re-definition of geographical limitations of stocks and connectivity, identification of fine-scale stock structure linked to locally adapted subpopulations, or even the integration with individual-based biophysical models to explore life history strategies. While those clearly enhance our perception of patterns at the light of a spatial scale, temporal depth and consequently forecasting ability might be compromised as an analytical trade-off. Here, we present a framework to reinforce our understanding of stock dynamics by adding also a temporal point of view. We propose to integrate genomic information on temporal projections of species distributions computed by Species Distribution Models (SDMs). SDMs have the potential to project the current and future distribution ranges of a given species from relevant environmental predictors. These projections serve as tools to inform about range expansions and contractions of fish stocks and suggest either suitable locations or local extirpations that may arise in the future. However, SDMs assume that the whole population respond homogenously to the range of environmental conditions. Here, we conceptualize a framework that leverages a conventional Bayesian joint-SDM approach with the incorporation of genomic data. We propose that introducing genomic information at the basis of a joint-SDM will explore the range of suitable habitats where stocks could thrive in the future as a function of their current evolutionary potential.Fundação para a Ciência e Tecnollogia - FCT; ARNETinfo:eu-repo/semantics/publishedVersio

Human-induced evolution: Signatures, processes and mechanisms underneath anthropogenic footprints on natural systems

The impact of human activities on the global environment has increased to such an extent that the current geological era has been coined the Anthropocene. Studies dedicated to understanding the evolutionary consequences of human-induced selection on all levels of diversity (species, populations, traits, genes) provide direct knowledge about the mechanisms underlying species' responses and their evolutionary potential. A better understanding of the effects of human-induced selection is needed to leverage evolved mechanisms to develop appropriate conservation programmes to guarantee the maintenance of healthy systems. In this special issue, we focus on different types of human-mediated selection pressures, from the direct harvesting of individuals (e.g. hunting, fishing), to the more pervasive effects of climate change. Contributions highlight the diversity of human-induced selection pressures ranging from fisheries, trophy-hunting, poaching and domestication to climate change, and pollution. With those, we question whether there are parallel evolutionary solutions across fisheries systems, whether hunting pressures alter population dynamics and population structure, and whether climate change is an evolutionary dead-end. The contributions reflect the direction of travel of the field and the solutions to mitigate the impact of human activities

Towards a unified eco-evolutionary framework for fisheries management: Coupling advances in next-generation sequencing with species distribution modelling

The establishment of high-throughput sequencing technologies and subsequent large-scale genomic datasets has flourished across fields of fundamental biological sciences. The introduction of genomic resources in fisheries management has been proposed from multiple angles, ranging from an accurate re-definition of geographical limitations of stocks and connectivity, identification of fine-scale stock structure linked to locally adapted sub-populations, or even the integration with individual-based biophysical models to explore life history strategies. While those clearly enhance our perception of patterns at the light of a spatial scale, temporal depth and consequently forecasting ability might be compromised as an analytical trade-off. Here, we present a framework to reinforce our understanding of stock dynamics by adding also a temporal point of view. We propose to integrate genomic information on temporal projections of species distributions computed by Species Distribution Models (SDMs). SDMs have the potential to project the current and future distribution ranges of a given species from relevant environmental predictors. These projections serve as tools to inform about range expansions and contractions of fish stocks and suggest either suitable locations or local extirpations that may arise in the future. However, SDMs assume that the whole population respond homogenously to the range of environmental conditions. Here, we conceptualize a framework that leverages a conventional Bayesian joint-SDM approach with the incorporation of genomic data. We propose that introducing genomic information at the basis of a joint-SDM will explore the range of suitable habitats where stocks could thrive in the future as a function of their current evolutionary potential

Recruitment collapse and population structure of the European eel shaped by local ocean current dynamics

Highlights: • We combine high-resolution ocean models with population genetics • Variation in wind-driven ocean currents mediates the collapse of A. anguilla • Female eels are philopatric within the Sargasso Sea, while males maintain gene flow • We present first evidence of the role of ocean currents in shaping species’ evolution Summary: Worldwide, exploited marine fish stocks are under threat of collapse [1]. Although the drivers behind such collapses are diverse, it is becoming evident that failure to consider evolutionary processes in fisheries management can have drastic consequences on a species’ long-term viability [2]. The European eel (Anguilla anguilla; Linnaeus, 1758) is no exception: not only does the steep decline in recruitment observed in the 1980s [ 3 and 4] remain largely unexplained, the punctual detection of genetic structure also raises questions regarding the existence of a single panmictic population [ 5, 6 and 7]. With its extended Transatlantic dispersal, pinpointing the role of ocean dynamics is crucial to understand both the population structure and the widespread decline of this species. Hence, we combined dispersal simulations using a half century of high-resolution ocean model data with population genetics tools. We show that regional atmospherically driven ocean current variations in the Sargasso Sea were the major driver of the onset of the sharp decline in eel recruitment in the beginning of the 1980s. The simulations combined with genotyping of natural coastal eel populations furthermore suggest that unexpected evidence of coastal genetic differentiation is consistent with cryptic female philopatric behavior within the Sargasso Sea. Such results demonstrate the key constraint of the variable oceanic environment on the European eel population

A noninvasive eDNA tool for detecting sea lamprey larvae in river sediments: Analytical validation and field testing in a low-abundance ecosystem.

Anthropogenic activities are increasingly threatening aquatic biodiversity, especially anadromous species. Monitoring and conservation measures are thus required to protect, maintain and restore imperilled populations. While many species can be surveyed using traditional capture and visual census techniques, species that use riverine habitats in a less conspicuous manner, such as sea lamprey Petromyzon marinus, can be more challenging to monitor. Sea lamprey larvae (ammocoetes) can spend several years in freshwater burrowed within soft sediments, inhibiting their detection and assessment. Here, we present a qPCR assay based on the detection of environmental DNA (eDNA) to identify the presence of ammocoetes burrowed in the sediment. We present an extensively validated method that ensured both species-specificity of the assay as well as the capacity to detect ammocoetes when abundances are low. Experiments on burrowing activity suggested that most of the DNA released into the sediment occurs during burrowing. Overall, we demonstrate this new molecular-based tool is an efficient and effective complement to traditional monitoring activities targeting larval stages of sea lampreys

Conservation of genetic uniqueness in remaining populations of red squirrels (Sciurus vulgaris L.) in the South of England

The Eurasian red squirrel (Sciurus vulgaris) is an emblematic species for conservation, and its decline in the British Isles exemplifies the impact that alien introductions can have on native ecosystems. Indeed, red squirrels in this region have declined dramatically over the last 60 years due to the spread of squirrelpox virus following the introduction of the gray squirrel (Sciurus carolinensis). Currently, red squirrel populations in Britain are fragmented and need to be closely monitored in order to assess their viability and the effectiveness of conservation efforts. The situation is even more dramatic in the South of England, where S. vulgaris survives only on islands (Brownsea Island, Furzey Island, and the Isle of Wight). Using the D‐loop, we investigated the genetic diversity and putative ancestry of the squirrels from Southern England and compared them to a European dataset composed of 1,016 samples from 54 populations. We found that our three populations were more closely related to other squirrels from the British Isles than squirrels from Europe, showed low genetic diversity, and also harbored several private haplotypes. Our study demonstrates how genetically unique the Southern English populations are in comparison with squirrels from the continental European range. We report the presence of four private haplotypes, suggesting that these populations may potentially harbor distinct genetic lineages. Our results emphasize the importance of preserving these isolated red squirrel populations for the conservation of the species

Population genetics and demography of the endemic mouse species of Cyprus, Mus cypriacus

Mus cypriacus is one of three small palaeoendemic mammals that have survived the Mediterranean islands’ anthropization. This species, endemic to Cyprus, was described in 2006 and stands out as one of the last mammal species to have been discovered in Europe. Despite scarce data on its genetics, ecology, and life-history traits, Mus cypriacus is assessed as Least Concern LC in the IUCN Red List, partly due to its morphological similarity with the sympatric house mouse that prevented earlier identification. Our study uses mitochondrial and microsatellite markers to investigate this small rodent's population genetic structure and diversity. Our analysis did not identify any population genetic structure and suggested a high genetic diversity across Cyprus. When inferring habitat preference using sample locations, it appeared that M. cypriacus utilizes a diverse variety of habitats, covering more than 80% of the island. Although these results are encouraging for the conservation status of the species, they still need to be cautiously applied as potential threats may arise due to increasing habitat destruction and changes in land use. Consequently, our encouraging results should be applied judiciously. Additional ecological data are urgently needed to gain a more comprehensive understanding of this inconspicuous endemic species