Impact of warming on abundance and occurrence of flatfish populations in the Bay of Biscay (France)

Abstract

International audienceThe aim of the present study was to analyse the influence of warming on flatfish populations in the Bay of Biscay. 17 autumn cruises conducted from 1987 to 2006 over the whole shelf of the Bay of Biscay provided data for the abundance and occurrence of adults for twenty flatfish species. Trends in flatfish abundance were analysed with regard to geographic range of populations and interannual fluctuations in abundance were related to seawater temperature. Results showed significant trends in abundance and occurrence for 55% of the flatfish species in the Bay of Biscay. The response to warming of seawater was correlated to geographic ranges of species. While the abundance of the northern temperate species decreased, that of southern ones increased. Moreover, for 40% of the species which densities have significantly changed, abundances were correlated to temperatures in their year of birth, positively for southern species and negatively for northern ones. Last, the abundance of flatfish adults over the Bay of Biscay was compared to previous data on juveniles in the Bay of Vilaine, one of the estuarine nursery ground in this area. For the northern species which have disappeared, the decline in juvenile abundances preceded that of adults by several years, indicating that the recruitment is the process affected. We concluded on a major impact of warming to explain changes in flatfish species abundances. Nevertheless, the impact of fishing interacts with that of climate change because the exploited species appeared to be the most negatively affected

Abrupt shifts in the Gironde fish community: an indicator of ecological changes in an estuarine ecosystem

“…Goberville et al 2010). On the other hand, this result also corroborates the observations of other authors, who previously observed that diadromous species are sensitive to climate change and increases in temperature (see Lassalle et al 2009 for a global study, Pronier & Rochard 1998for smelt, and Cabral et al 2001and Hermant et al 2010 for flounder in the Bay of Biscay and the Tagus). Despite this global trend for diadromous species, we observed a brief recovery of allis shad abundance in the community during the beginning of this period, stressing that the driving factors are complex for this particular population (Rougier et al 2012) and are probably specific to each diadromous fish population.…”

Responses of Marine Organisms to Climate Change across Oceans

“…Species responses are complex and likely tempered by ecological characteristics, trophic interactions and resource availability, as well as other anthropogenic stressors, such as pollution and fishing. Fishing is a pervasive stressor in marine ecosystems (Worm et al, 2009;Branch et al, 2010) and its effects appear to increase sensitivities of ecological responses to climate change (Hsieh et al, 2008;Rijnsdorp et al, 2009;Hermant et al, 2010;Bates et al, 2014a).…”

“…Evidence of similar mechanisms are shown in other taxonomic groups. For example, variability in abundances of 20 flatfish species in the Bay of Biscay, north-east Atlantic (1987Atlantic ( -2006, were linked to sea surface temperatures in the year of their birth, suggesting that larval survival and recruitment processes influenced adult abundances (Hermant et al, 2010).…”

Latitudinal trends in habitat quality of shallow‑water flatfish nurseries

“…Instead, thermal stress has been suggested as a possible cause for hampering growth rates in sole as summer temperatures largely exceed metabolic optimum temperatures . Excessive temperatures have also been suggested as the mechanism responsible for the drastic decline in flounder observed in recent years in this estuary (Cabral et al , 2007, and for a disruption in plaice recruitment in the Bay of Biscay (Désaunay et al 2006, Hermant et al 2010.…”