Regime shifts in fish recruitment on the Northeast US Continental Shelf

ABSTRACT: There is accumulating evidence for decadal-scale regime shifts at the base of the food web on the Northeast US Continental Shelf. However, less evidence exists for regime shifts in fish recruitment success, particularly for synchronized regimes across multiple species. Here, we analyzed stock assessment output and survey data to test for regimes in the recruitment success of 18 commercially important marine species over a 29 yr timespan. We then tested whether recruitment regimes coincide with regimes in the zooplankton community, and whether the abundance of large spawners could explain the patterns in recruitment. We found evidence for 3 decadal-scale recruitment regimes: low recruitment success in the 1980s, high success in the 1990s, and a return to low recruitment success in the 2000s. This general pattern was found in all datasets of recruitment. The abundance of large spawners did not appear to be a broad-scale driver of recruitment success; however, recruitment regimes coincided with regimes in copepod abundance and size structure.