Multidecadal growth‐increment chronologies for North Pacific and North Atlantic rockfish species

No abstracts are to be cited without prior reference to the author.

Tree‐ring (dendrochronology) techniques have been increasingly applied to develop environmentally sensitive growth chronologies from annual otolith increment widths of various rockfish (Sebastes) species. Final chronologies are multidecadal, exactly dated, and can be used to (i) describe long‐term growth histories, (ii) determine the effects of climate on growth, and (iii) integrate with other biological time‐series to quantify relationships across diverse taxa and ecosystems. In the California Current of the Northeast Pacific, splitnose and yelloweye rockfish chronologies span as many as 71 years and strongly relate to each other as well as other biological indicators, including records of seabird reproductive success. Synchrony across these diverse timeseries is driven by their shared sensitivities to winter ocean conditions, and years with favourable climate (strong February and March upwelling) are characterized by robust rockfish growth, early seabird lay dates, and high fledgling success. These results provide long‐term, corroborating evidence as to the importance of winter ocean conditions for ecosystem productivity. Similar approaches are also possible for Atlantic rockfish species. A 30‐year Acadian redfish (S. fasciatus) chronology has recently been developed for the Gulf of Maine, which significantly (p < 0.01) correlates to climate indices, especially the Atlantic Multi‐decadal Oscillation. These correlations indicate that cool conditions are associated with strong growth, consistent with species in the Pacific. Overall, chronology development could be more widely applied in the North Atlantic to better understand long‐term rockfish growth patterns, their relationships to climate, and interactions with other biological components of the ecosystem.