Contrasted spatio-temporal changes in the demersal fish assemblages and the dominance of the environment vs fishing pressure, in the Bay of Biscay and Celtic Sea

Eme, David; Rufino, Marta M.; Trenkel, Verena M.; Vermard, Youen; Laffargue, Pascal; Petitgas, Pierre; Pellissier, Loïc; Albouy, Camille

doi:10.1016/j.pocean.2022.102788

Cited by 10 publications

(8 citation statements)

References 95 publications

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“…Although fishing pressure was found to be the dominant driver in the Celtic Sea the integration of environmental variables, particularly temperature and primary production, improved the fit of the ecological model (Hernvann et al, 2020). Interestingly, other studies that focused on the Celtic Sea in a similar time frame found that the structure of demersal assemblages were driven by depth, chlorophyll a and bottom temperature (Meŕillet et al, 2020) and the abundance of demersal species was driven by the abundance of small pelagics (e.g., European anchovy) via a bentho-pelagic trophic link (Eme et al, 2022). Considering the different results of the reported studies the relative importance of fishing and the environment on the abundance of demersal populations in the Celtic Sea remains unclear.…”

Section: Introductionmentioning

confidence: 82%

“…We tested the hypothesis that the abundance of demersal stocks in the Celtic Sea from 1997 to 2019 (23 years) was driven by both fishing pressure and the environment. To reduce the risk of identifying spurious relationships and overfitting models we selected variables that characterize key components of the Celtic sea ecosystem based on recent studies (Goikoetxea and Irigoien, 2013;Hernvann et al, 2020;Meŕillet et al, 2020;Eme et al, 2022). To account for autocorrelation and non-stationary processes in the data we applied multivariate techniques that account for temporal structures.…”

Section: Introductionmentioning

confidence: 99%

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Trends in the abundance of Celtic Sea demersal fish: Identifying the relative importance of fishing and environmental drivers

et al. 2022

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The Celtic Sea is a productive fishing ground, therefore identifying the relative importance of fishing and environmental factors on fish stock dynamics is crucial for developing our understanding of sustainable yields and to operationalize Ecosystem Based Fisheries Management (EBFM). We investigated the effect of environmental variables and fishing on the relative abundance inferred from catch-per-unit-effort (CPUE), of twelve demersal stocks (i.e., cod, haddock, whiting, anglerfish, hake, megrim, plaice, sole, lesser-spotted dogfish, spurdog, Trisopterus spp., skates and rays) in the Celtic Sea from 1997 to 2019 (23 years). Annualized time series (1997-2019) of net primary production, bottom temperature, copepod abundance (Calanus finmarchicus and Calanus helgolandicus) and North Atlantic Oscillation index were used to characterize key environmental variables. Fishing exploitation rates (F/FMSY) were used to represent fishing pressure and CPUE trends derived from an International Bottom Trawl Survey (IBTS) were used to infer abundance. We used redundancy analysis to identify key explanatory variables and then dynamic factor analysis to assess their relationships with the CPUE series and identify underlying patterns in the unexplained temporal variation. Our results show that for the majority of demersal fish species, the CPUE trends were strongly influenced by fishing exploitation rates. The gradual reduction in exploitation rates observed throughout the study period most likely led to the partial recovery of cod, spurdog, hake, megrim, plaice, whiting, Trisopterus spp., and the skates and rays. In addition, exploitation patterns on one stock influenced CPUE trends of other demersal stocks (e.g., hake, megrim, plaice, lesser-spotted dogfish, sole). We also observed that the CPUE of whiting, hake and plaice increased when C. finmarchicus were abundant in the plankton. We infer from our findings in the investigated time series that the recovery of cod, spurdog, hake, megrim, plaice, whiting, Trisopterus spp., and the skates and rays in the Celtic Sea remains dependent on controlling fishing mortality, and this would not, at least for now, be confounded by the environmental conditions.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Trends in the abundance of Celtic Sea demersal fish: Identifying the relative importance of fishing and environmental drivers

et al. 2022

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“…Furthermore, we have yet to see apparent signs of recovery in biomass and ecosystem indicators (Gascuel et al., 2016). Additionally, reductions in mortality have not been homogeneous across the study area: fishing pressure was mainly localized in the eastern areas of both the CS and the BoB, and has climbed over the past 20 years in the western and northwestern parts of the CS, as well as in the eastern BoB (Eme et al., 2022). This spatial heterogeneity in fishing pressure might have led to the southward and eastward shifts of the taxa with a greater commercial importance in the CS and along the CBS.…”

Section: Discussionmentioning

confidence: 99%

Northeast Atlantic species distribution shifts over the last two decades

Le Luherne,

Pawlowski,

Robert

2024

Global Change Biology

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Marine species are widely shifting their distributions in response to global changes and it is commonly expected they will move northward and to greater depths to reach cooler, less disturbed habitats. However, local manifestations of global changes, anthropogenic pressures, and species characteristics may lead to unanticipated and varied responses by individual species. In this regard, the Celtic‐Biscay Shelf is a particularly interesting study system because it has historically been heavily fished and occurs at the interface between two distinct biogeographic provinces, its community thus comprised of species with diverse thermal preferenda. In the context of rapidly warming temperatures and intense fishery exploitation, we investigated the distribution shifts of 93 taxa (65 Actinopteri, 10 Elasmobranchii, 11 Cephalopoda, 5 Malacostraca, and 2 Bivalvia), which were sampled annually from 1997 to 2020 during a scientific bottom trawl survey. We used a set of 11 complementary spatial indices to quantify taxon distribution shifts over time. Then, we explored the relative effect of taxon abundance, fishing pressure, and climatic conditions on taxon's distribution shift when a significant shift was detected. We observed that 56% of the taxa significantly shifted. Not all taxa will necessarily shift northward and to deeper areas, as it is often expected. Two opposite patterns were identified: taxa either moving deeper and to the southeast, or moving closer to the surface and to the northwest. The main explanatory factors were climate change (short‐ and long‐term temperatures) and taxon abundance. Fishing pressure was the third, but still significant, explanatory factor of taxa of greater commercial importance. Our research highlights that taxa are displaying complex distribution shifts in response to the combined anthropogenic disturbances and underscores the need to conduct regional studies to better understand these responses at the ecosystem scale to develop more suitable management plans and policies.

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“…SST, EKE, and Chl-a, which are all intrinsically connected with species physiology and ecology, and are likely to be the main drivers of foraminifera diversity. For example (1) SST, an index of solar energy input, influences the kinetics of biochemical reactions, metabolic rates and, thus, the probability of species mutation (Rhode, 1992;Allen et al, 2006;Eme et al, 2022), (2) Chl-a, as an index of productivity and food supply, determines population abundances, which are also directly related to the probability of mutation and species adaptation (Roy et al, 1998;Morey et al, 2005), and (3) kinetic energy, represented by EKE is a proxy for water column instability and ocean fronts, therefore it influences the rate of immigration and the probability of local extinction. These three variables reflect the main changes of energy between the individuals and the environment.…”

Section: Impact Of Sstmentioning

confidence: 99%

Ocean kinetic energy and photosynthetic biomass are important drivers of planktonic foraminifera diversity in the Atlantic Ocean

et al. 2022

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To assess the anthropogenic effect on biodiversity, it is essential to understand the global diversity distribution of the major groups at the base of the food chain, ideally before global warming initiation (1850 Common Era CE). Since organisms in the plankton are highly interconnected and carbonate synthesizing species have a good preservation state in the Atlantic Ocean, the diversity distribution pattern of planktonic foraminifera from 1741 core-top surface sediment samples (expanded ForCenS database) provides a case study to comprehend centennial to decadal time-averaged diversity patterns at pre-1970 CE times, the tempo of the substantial increase in tropospheric warming. In this work, it is hypothesized and tested for the first time, that the large-scale diversity patterns of foraminifera communities are determined by sea surface temperature (SST, representing energy), Chl-a (a surrogate for photosynthetic biomass), and ocean kinetic energy (as EKE). Alpha diversity was estimated using species richness (S), Shannon Wiener index (H), and Simpson evenness (E), and mapped using geostatistical approaches. The three indices are significantly related to SST, Chl-a, and EKE (71-88% of the deviance in the generalized additive mixed model, including a spatial component). Beta diversity was studied through species turnover using gradient forest analysis (59% of the variation). The primary community thresholds of foraminifera species turnover were associated with 5-10 °C and 22-28 °C SST, 0.05-0.15 mg m-3 Chl-a, and 1.2-2.0 cm2 s-2 log10 EKE energy, respectively. Six of the most important foraminifera species identified for the environmental thresholds of beta diversity are also fundamental in transfer functions, further reinforcing the approaches used. The geographic location of the transition between the four main biogeographic zones was redefined based on the results of beta diversity analysis and incorporating the new datasets, identifying the major marine latitudinal gradients, the most important upwelling areas (Benguela Current, Canary Current), the Equatorial divergence, and the subtropical fronts (Gulf Stream-North Atlantic Drift path in the north, and the South Atlantic current in the south). In conclusion, we provide statistical proof that energy (SST), food supply (Chl-a), and currents (EKE) are the main environmental drivers shaping planktonic foraminifera diversity in the Atlantic ocean and define the associated thresholds for species change on those variables.

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Contrasted spatio-temporal changes in the demersal fish assemblages and the dominance of the environment vs fishing pressure, in the Bay of Biscay and Celtic Sea

Cited by 10 publications

References 95 publications

Trends in the abundance of Celtic Sea demersal fish: Identifying the relative importance of fishing and environmental drivers

Trends in the abundance of Celtic Sea demersal fish: Identifying the relative importance of fishing and environmental drivers

Northeast Atlantic species distribution shifts over the last two decades

Ocean kinetic energy and photosynthetic biomass are important drivers of planktonic foraminifera diversity in the Atlantic Ocean

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