Introduction

The above analysis of the total production of salted herring is also relevant to the question whether or not the amount of herring extracted from the North Sea in the 1600-1850 period could significantly impact the abundance of North Sea herring. A historical study suggests this by asking whether ‘Perhaps overfishing reduced the catches…’.

If the herring fisheries during the 1600-1850 period impacted fish stocks, the fishing pressure would have to be taken into account in applying fisheries data as a reflection of the spatial movement and relative abundance of herring stocks over this long time span. If, however the fisheries had an insignificant impact on stock abundance, then fishing pressure can be taken out of this equation. One way to address this issue is to compare the past catches of North Sea herring with today's knowledge as to how much herring can be taken from the North Sea in a sustainable manner.

Present distribution of North Sea herring

The population of herring in the North Sea consists of both spring spawning and autumn spawning herring. The autumn spawning stocks are the most prolific and these were the potential targets of Dutch fishers. The autumn spawning herring in the North Sea consist of three sub-populations or stocks, primarily separated by a different spawning behaviour and characteristics. The Northern stock, Buchan herring spawn in the area in between the Shetland Islands and the Scottish east coast off Aberdeen. The Bank herring has spawning grounds off the English coastline in between Yorkshire and Norfolk and on Dogger Bank, in the central North Sea. The third and southernmost herring stock in the North Sea is the Downs herring, which spawn in the Southern Bight of the North Sea and the English Channel. The Buchan herring tend to spawn first, followed by the Dogger while the Downs herring spawn in late autumn. In winter and spring all three sub-populations drift around the North Sea in a counter clockwise movement, wintering in the eastern part of the North Sea, while the Buchan and Dogger stocks move on the North Eastern areas during spring, feeding on zoo-plankton, primarily Calanus finnmarchicus. In early summer around June the Buchan herring reach the Shetlands, which is where the Dutch fishers would await the start of the fishing season, on the night of St. John, the 24th of June.