Lipid-correction models for δC values across small pelagic fishes (Clupeiformes) from the Atlantic Ocean.

The interpretation of δC values in trophic ecology requires standardization of the lipid content of organisms estimated through their C:N ratio. To avoid time-consuming lipid extractions, the use of mathematical corrections has been developed for many years, and the conclusions generally point in the direction of species-specific adjustment of the models. This study aimed at defining the maximum taxonomic level required to obtain the best corrected δC values in small pelagic fish of the order Clupeiformes.

Different mechanisms underpin the decline in growth of anchovies and sardines of the Bay of Biscay.

Declines in individuals' growth in exploited fish species are generally attributed to evolutionary consequences of size-selective fishing or to plastic responses due to constraints set by changing environmental conditions dampening individuals' growth. However, other processes such as growth compensation and non-directional selection can occur and their importance on the overall phenotypic response of exploited populations has largely been ignored. Using otolith growth data collected in European anchovy and sardine of the Bay of Biscay (18 cohorts from 2000 to 2018), we parameterized the breeder's equation to determine whether declines in size-at-age in these species were due to an adaptive response (i.

Effects of hunting on genetic diversity, inbreeding and dispersal in Finnish black grouse ().

Intensive hunting activities such as commercial fishing and trophy hunting can have profound influences on natural populations. However, less intensive recreational hunting can also have subtle effects on animal behaviour, habitat use and movement, with implications for population persistence. Lekking species such as the black grouse () may be especially prone to hunting as leks are temporally and spatially predictable, making them easy targets.

Ocean acidification alters the acute stress response of a marine fish.

The absorption of anthropogenic carbon dioxide from the atmosphere by oceans generates rapid changes in seawater carbonate system and pH, a process termed ocean acidification. Exposure to acidified water can impact the allostatic load of marine organism as the acclimation to suboptimal environments requires physiological adaptive responses that are energetically costly. As a consequence, fish facing ocean acidification may experience alterations of their stress response and a compromised ability to cope with additional stress, which may impact individuals' life traits and ultimately their fitness.

Temporal variations in scale cortisol indicate consistent local-and broad-scale constraints in a wild marine teleost fish.

Environmental changes can alter the nursery function of coastal areas through their impact on juveniles' growth and survival rates, an effect mediated by individuals' chronic stress response. Fish chronic stress can be quantified using scale cortisol but no study has yet been quantified the spatio-temporal variations in scale cortisol and its relationship with growth in wild nurseries. We collected wild sea bass juveniles (Dicentrarchus labrax, four years, three nurseries) and found that scale cortisol levels increased consistently with age and across cohorts in 2019 and 2020 probably due to greater stress history in older fish and/or heatwaves that occurred in summers of 2018 and 2019.