Biology subjects

Senay, C.

Publications and source records attributed to Senay, C..

3 recordsLinked to original sources

bioRxiv2025

Population genomics reveals fine-scale three-dimensional structure within two sympatric Sebastes species in the Northwest Atlantic

An ideal fishery stock assessment requires a comprehensive understanding of population structure across landscapes. In the Gulf of St. Lawrence and the Laurentian Channel (GSL-LC), massive Sebastes recruitments occurred in early 2010s, nearly 30 years after the last strong cohort. This recruitment had resulted in abundant Sebastes mentella, but also involved the morphologically nearly indistinguishable S. fasciatus. Both species show multiple populations, but spatially explicit information at a management- relevant scale is lacking to support robust scientific advices for sustainable fisheries. Temporal variation in the Sebastes recruitment also remains poorly characterized, and it is unknown if the recruitment is synchronized at the species or population level. This study aimed to 1) characterize the current fine- scale genomic structure of S. mentella and S. fasciatus in the GSL-LC, 2) compare the genetic composition of different cohorts, and 3) evaluate relationship between genomic structure and two key factors in redfish management, depth, and management units. Our genomic datasets (> 16,000 SNPs, N = 2,248 redfish) revealed substructure within the previously identified S. mentella GSL ecotype and five S. fasciatus populations within the GSL-LC. While all genetic groups were represented in the recent cohort samples, our results suggested unequal contributions of S. fasciatus populations to massive recruitment events. The spatial distribution of genetic groups within both species revealed a three- dimensional structure tied to management units and depth. Our findings underscore the importance of revising management measures to incorporate population structure thereby reducing the risk of overexploiting smaller populations, particularly S. fasciatus, and promoting sustainable fisheries.

genomics↗

bioRxiv2025

Past environments modulate response to fluctuating temperatures in a marine fish species

The rise in ocean temperatures predicted due to the global warming will impact the survival and structure of various marine organisms, in particular ectothermic organisms. Phenotypic plasticity enables species to cope with environmental changes, providing a vital buffer for evolutionary changes. Yet, the dynamics and the molecular mechanisms underpinning these plastic responses remain largely unexplored. Here, we assessed the impact of acclimation environment on organisms capacity for thermal plasticity. We conducted a genome-wide transcriptomic analysis on the Acadian redfish, S. fasciatus, exposed to four temperatures (2.5, 5.0, 7.5 and 10.0 ) over a long-term period (up to 10 months) followed by an acute temperature change (24 hours), simulating natural fluctuation condition the species could encounter. Our results showed a dynamic transcriptional response to temperature involving various genes functions. The rapid response to temperature shifts, coupled with the sustained expression of specific genes over an extended period highlighted the species capacity for plastic response to temperature changes. We also detected a significant effect of the interaction between the long and short terms temperature exposure on gene expression, highlighting the influence of the past environment on response to acute temperature changes. Specifically, fish acclimated to higher temperatures demonstrated an increased stress-related response to environmental fluctuations, as evidenced by both the shape of their reaction norms and the implication of stress-related gene functions. This result suggests that temperature conditions predicted for the near future in the Northwest Atlantic will trigger less adaptive plasticity to environmental fluctuations, highlighting the species vulnerability to ocean warming.

ecology↗

bioRxiv2025

Warming, but not acidification, increases metabolism and reduces growth of redfish (Sebastes fasciatus) in the Gulf of St. Lawrence.

Understanding the effects of global change, including temperature, pH, and oxygen availability, on commercially important species is crucial for anticipating consequences for these resources and their ecosystems. In the Gulf of St. Lawrence (GSL), redfish (Sebastes spp.) have been under moratorium from 1995 to 2024, with a massive recruitment observed in 2011-2013. However, little is known about their metabolic and thermal physiology, making predictions of their response to changing GSL conditions challenging. To address this, we quantified the effects of four acclimatation temperatures (2.5, 5.0, 7.5, and 10.0 ) and two pH levels (7.35 and 7.75) on standard and maximum metabolic rates (SMR and MMR), aerobic scope (AS), hypoxia tolerance (O2crit), food consumption, and growth in redfish. SMR, MMR, and AS increased with temperature, but growth decreased at the highest temperature, likely due to increased metabolic demand, with food consumption similar across 5.0 to 10.0 {degrees}C treatments. O2crit was lower for fish acclimated to 2.5 and 5.0 , making redfish less hypoxia-tolerant at higher temperatures. Except from SMR, no significant effect of pH was observed. These results suggest that future changes in the GSL will challenge redfish, with potential long-term effects on their growth due to increased energy requirements.

physiology↗