Distribution of Atlantic herring (Clupea harengus) in the Gulf of Maine from 1998 to 2012

Abstract

Atlantic herring (Clupea harengus) in the Gulf of Maine were surveyed using fisheries-independent systematic and stratified-random surveys conducted annually by the Northeast Fisheries Science Center from 1998 to 2012 during autumn. The systematic surveys were dedicated to surveying Atlantic herring and were designed to be synchronous with pre-spawning, whereas the stratified-random surveys were broad-scale, multi-species surveys. Both types of surveys collected multi-frequency acoustic and trawl data. These surveys were analyzed to evaluate their individual effectiveness as surveys, whether results could be combined, or whether either survey could be used alone to estimate Atlantic herring abundance. With the exception of two years, more Atlantic herring in the water column were observed in the Georges Bank region during the dedicated systematic survey than later in the season by the stratified-random survey in the Georges Bank and northern Gulf of Maine regions. These observations suggest that the systematic survey was not out of synchrony with Atlantic herring spawning in the Georges Bank area, and the majority of spawning in the off-shore Gulf of Maine region occurred in the Georges Bank area. Additionally, the area backscattering time series showed no dramatic changes among surveys conducted with different vessels, suggesting that the Atlantic herring did not react substantially to changes in vessels and/or reacted similarly to the presence of any of the four vessels used.