Long-term variability of the siphonophores Muggiaea atlantica and M. kochi in the Western English Channel

摘要: We investigated long-term variability of the calycophoran siphonophores Muggiaea atlantica and kochi in Western English Channel (WEC) between 1930 2011. Our aims were to describe changes abundance temporal distribution relation local environmental dynamics. In order better understand mechanisms that regulate species’ populations, we identified periods characteristic situ population growth optima associated with these events. results show 1960s both M. transient components WEC ecosystem. late atlantica, successfully established a resident WEC, while occurrence became increasingly sporadic. Once as species, seasonal increased. Analysis conditions revealed temperature prey key determinants atlantica. Salinity was shown have an indirect effect, likely representing proxy for water circulation WEC. Anomalies cycle salinity, indicating deviation from usual pattern negatively growth, suggesting dispersal locally developing population. However, our findings complexity relationship characteristics environment variability. The transition period transiency (1930–1968) residency (1969–2011) tentatively attributed structural ecosystem occurred under forcing wider-scale hydroclimatic changes.