Trenkel Verena's research while affiliated with Imperial College London and other places

... All individuals belonging to fourteen target species (Table 1) were measured at the lowest 0.5 cm (deep-water rose shrimp at the lowest 1 mm) as dorsal mantle length (ML, cephalopods), carapace length from eye socket to dorsal posterior carapace margin (CL, deep-water rose shrimp), and total length (TL, fishes). The size structure of each selected species was described by its length frequency distribution (LFD) and by the following length-based indices [52][53][54]: To test the effect of the trawl ban on the biomass (kg/km 2 ) of the total trawlable assemblage, a BACI (before-after-control-impact) with a multiple controls asymmetrical experimental design [56,57] was adopted with three factors: Time, fixed, with two levels (before-1990 and after-1990); Status, fixed, with two levels (Trawled and Untrawled); and Locality, random and nested within Status, with two levels under the group Trawled (GTERM and GSANT) and one level under the group Untrawled (GCAST). Thirty-two replicates randomly selected from a dataset of about 500 hauls were considered for each combination of Time/Locality (n = 204). ...

... The biodiversity in marine ecosystems is the result of the complex interconnection among all co-occurring organisms at different trophic levels, and the loss of just one ecological level may have severe effects on the functioning of the entire ecosystem community. Within this complex set of interspecific relationships, fish assemblage structure can be affected by several natural and anthropogenic processes, such as overfishing, pollution, habitat loss, and climate change (Jennings and Kaiser, 1998;Gray et al., 2005;Poulard and Blanchard, 2005;Lehodey et al., 2006;Rijnsdorp et al., 2009;Rochet et al., 2010). Therefore, a deeper understanding of the functioning of ecosystem-level processes is necessary to mitigate potential unsustainable exploitation and biodiversity losses and to support management approaches (Pikitch et al., 2004;Mittermeier et al., 2011). ...

... Acoustic technology has evolved an enormous amount in recent years. Scientific multibeam echosounders can now disclose the true 3D morphology of fish schools, sometimes revealing more complex patterns than those observed through single beam data Berger et al., 2009). Broadband multi channel acoustics can provide a much better vertical resolution of the data through pulse compression techniques and allow the classification of schools through spectral analysis of the volume backscattering coefficient (e.g. ...

... Here, we apply the LIM approach to explore the predictability of a set of fisheries time series describing the temporal changes of specific stocks. These time series can be viewed as proxies that simplify complicated biological and socioeconomic conditions over time [Blanchard et al., 2010;Tam et al., 2019]. The three fisheries databases considered in this study are (1) stock biomass anomalies from scientific stock assessments performed for a limited number of stocks in different regions (RAM database, [Ricard et al., 2012]), (2) landings of stocks as reported by the country targeting the species (LME database, [Pauly et al., 2020]), and (3) the catches of species that are estimated from data reported to the United Nations (FAO database [Pauly et al., 1998]). ...

... Acoustic heads were immerged at 1.25m depth and installed on the vessel "Albert Lucas", from the "flotte océanographique française" ("Flotte océanographique française," 2021) at Brest, France. Acoustic data have been cleaned and treated using Matecho (Perrot et al., 2018) software, based on Movies 3D algorithm (Trenkel et al., 2009) to obtain echo-integrated data and shoal information. Echointegration and shoal extraction methodologies were used to produce morphological, spatial and acoustic descriptors of fish shoals and other components of the biocenoses within the water column. ...

... A better knowledge of species interactions is consequently a major issue of the EAF in order " to balance diverse societal objectives, by taking into account the knowledge and uncertainties about biotic, abiotic and human components of ecosystems and their interactions and applying an integrated approach to fisheries within ecologically meaningful boundaries " (FAO, 2008). The high diversified marine fauna from the Bay of Biscay (north-eastern Atlantic) has supported numerous fisheries over a long period of time (Lorance et al., 2009) and still is largely exploited. The five highest landed value species exploited in the Bay of Biscay in 2012–2014 are common sole (Solea solea), hake (Merluccius merluccius), sea bass (Dicentrarchus labrax), Norway lobster (Nephrops norvegicus) and monkfish (Lophius spp.) (SIH Ifremer, http://sih. ...

... This identification is traditionally based on the use of morphological keys that often provide effective tools to identify rapidly and accurately numerous specimens. For instance, thousands of fishes belonging to 220 species are commonly identified based on different field guides (Bauchot and Pras 1980;Quéro and Vayne 1997;Quéro et al. 2003) during an annual Ifremer's survey in the Bay of Biscay (Morin et al. 2009). Similarly, more than 30,000 specimens belonging to 30 fish species that go through one of the largest fish passes in Europe during their migration were identified in 2009 based on the analysis of morphological differences between species Table I -continued Summary of the DNA taxonomy proposal (Tautz et al. 2003) Overview of the main commentaries of the pros and cons The DNA taxonomic system will be derived from the data rather than expert opinion, and hypothesized species can be tested against morphology, biogeography, and other data, providing an evolutionary justification of the procedures used for species delimitation (Vogler and Monaghan 2007) 13. ...

... In this way, Actynopterygians that showed a wide range of individual lengths were subdivided into two groups, ''large Actynopterygians'' (56 ± 20 cm length on average), and ''small Actynopterygians'' (20 ± 9 cm length on average). The spatial distribution (which we assume to correspond to the habitat and/or the feeding zone) of the studied species was defined following the published literature (Lorance et al., 2000;Quéro, 2003;Palomares and Pauly, 2010), and published diet data of the area (Spitz et al., 2006aSpitz et al., , 2006bSpitz et al., , 2011), or derived from shipboard and aerial surveys in the area (Trenkel et al., 2009; Centre de Recherche sur les Mammifères Marins, La Rochelle, France, unpublished data). This spatial distribution was determined both on the vertical axis (i.e., pelagic, benthopelagic or benthic) and on the horizontal axis (i.e., from the coastline to the oceanic area: coastal/ shelf, shelf/upper slope, upper slope/deep-sea/oceanic) for each species. ...

... Esta situación es advertida principalmente en la XI región, en donde el monitoreo de la pesquería no es optimo por las condiciones extremas de la región. Por esta razón, es importante que los métodos de evaluación integren datos de muestreos y cruceros (Benoit et al., 2009) luego de un análisis riguroso de pertinencia. La integración de información independiente a la modelación pesquera es vital para tener contraste de los datos y mejorar las estimaciones. ...

... Long-term ecological surveys (LTES) are key to document temporal dynamics (Kuebbing et al., 2018), but their drawbacks should also be considered. First, variations in sampling effort over time or space are likely especially for LTES carried out over large spatial or temporal scales such as fish stock surveys (Trenkel & Cotter, 2009). For the EVHOE time series, it was crucial to use a sample-based rarefaction approach with resampling (e.g. ...