Tracking shifts in Atlantic mackerel (Scomber scombrus) larval habitat suitability on the Northeast U.S. Continental Shelf

Abstract

Climate change has altered the oceanographic environment and subsequently the habitats of marine species. Fish and invertebrate populations' responses to habitat include movement with latitude and depth to remain within their fundamental niches. The northwest Atlantic mackerel (Scomber scombrus) population has fluctuated over the last century due in part to changes in the environment. We used species distribution models to understand the influence of the physical (temperature) and biological (zooplankton) environment on mackerel larval abundance, and how such relations have determined larval habitat suitability in the Northeast U.S. Shelf.Atlantic mackerel larval presence and abundance correlated with sea temperature and copepod abundances, suggesting that larval survival may be sensitive to specific temperatures and zooplankton prey. Predicted abundances were spatially interpo- K E Y W O R D SAtlantic mackerel, habitat suitability, larvae, Northeast U.S. Shelf, sea temperature, species distribution models, zooplankton

Modelling Atlantic mackerel spawning habitat suitability and its future distribution in the north‐west Atlantic

“…Marine fish populations respond to climate vulnerability through distribution shifts poleward or to new depths (Nye, Link, Hare, & Overholtz, ). A northward shift in the distribution of mackerel larvae has been predicted in the north‐west Atlantic region (McManus et al, ). Although spawning habitats are predicted to decrease in June–July in this region which is presently the main spawning site for mackerel southern contingent, it is difficult to state whether this decrease could lead to spawning habitat shift based on this work.…”

“…Moreover, C. finmarchicus and Temora sp. abundances were also found to have great importance in determining mackerel larvae optimal habitat for the southern contingent (McManus et al, ).…”

“…It can be hypothesized that mackerel as an income breeder take advantage of the development of C. fincmarchicus during longer phytoplankton bloom to maximize spawning. Another hypothesis that could explain the best fit between egg densities and zooplankton is the fact that oceanographic processes prevailing during the spawning period concentrate eggs and zooplankton similarly (McManus et al, ).…”

“…Mackerel stock is a transboundary stock made up of a northern contingent that historically spawns in the southern Gulf of St. Lawrence (GSL; e.g. Castonguay, Plourde, Robert, Runge, & Fortier, ; Grégoire, Gendron, Beaulieu, & Lévesque, ) primarily in June and of a southern contingent that spawns in the southern Gulf of Maine in May (Anderson & Paciorkowski, ; Berrien, ; McManus, Hare, Richardson, & Collie, ; Sette, ; Figure and references therein). The two contingents mix off the US East Coast in the winter (Sette, ).…”

“…In particular, the combining effects of zooplankton and temperature conditions have been shown to affect habitat shift and population distributional range of migratory species (Broms, Melle, & Horne, ; Secor, ). For example, changes in water temperature and zooplankton abundances constrained mackerel geographical expansion in the north‐east Atlantic whereas they explained the north‐eastward shift of larval habitat suitability of the southern contingent in the north‐west Atlantic (McManus et al, ; Olafsdottir et al, ). Changes in distribution have not been reported for the northern contingent of north‐west Atlantic mackerel, but it is hypothesized that distribution changes have and might continue to occur due to previous and anticipated changes in the environmental conditions such as temperature and zooplankton abundance, composition and phenology, which are known to impact mackerel condition and recruitment in the GSL (Castonguay et al, ; Plourde et al, ).…”