Recent changes in ichthyoplanktonic assemblages of the eastern English Channel

Abstract

ish assemblages vary through time in both abundance and diversity, often due to changes in climate. The potential consequences of these changes on the larval phase need to be considered. In the Eastern English Channel, fish larvae of 30 taxa, from surveys conducted during spring in the nineties and in 2017 with bongo nets, were used to investigate seasonal and interannual changes in larval assemblages with different statistical tests and multivariate analyses (Outlying Mean Index, Principal Coordinate Analysis and variance partitioning). The major change observed was significant lower abundances in 2017 (in April and May) compared to the nineties. Most of the dominant taxa were two to three-fold less abundant in 2017 than the 1990s. We suggest that the reduced larval abundances in 2017 could be a consequence of lower adult abundances in the area from a switch from a colder to a warmer phase of the Atlantic Multidecadal Oscillation. Highlights► Larval assemblages were dominated by ten species. ► Overall abundances and diversity increased across the spring season. ► Larval abundances were significantly lower in 2017 compared to the nineties. ► Several larval and adult fish species responded similarly to a shift in the AMO.

Investigating environmental influence and temporal changes in sole (Solea solea) larvae condition using histology

“…abundances encountered in 1995 compared to 2017 are in line with the results of DiPane et al (2020a) where this difference was observed for several species of the area. The month ofMay (1995 and appeared to be the month when the highest abundance of sole larvae was encountered.…”

“…The filtered volume of seawater was calculated using a digital flowmeter fixed at the entry of each net. The content of the first net was dedicated to calculate fish larval abundances and was fixed in a buffered-formalin seawater solution (Di Pane et al, 2020a). Fish larvae from the second net were fixed in Bouin-Hollande solution for two days and then stored in ethanol 70° for two months before histological analyses.…”

Seasonal and ontogenetic variation of whiting diet in the Eastern English Channel and the Southern North Sea

“…Past [19] and present results confirm that Clupeidae are an abundant and accessible prey for large whiting in winter. During this period, Downs herring [74] and S. sprattus [75] gather in very large numbers in the EEC-SNS to mate and spawn. The large abundance of Clupeidae in large whiting stomachs reflects that the winter spawning migration of these species in the EEC represents an important trophic opportunity for whiting during a nutrient-poor period.…”