It is far more difficult to compare information on fishing due to differences in the collection of the remains concerned. The differences relate to both the mesh width of the employed sieves and the sampling strategy. Sturgeon is a case apart on account of its many readily identifiable but vulnerable dermal plates. At sites with fairly poor preservation conditions such large quantities of sturgeon fragments result in high scores. Concentrations of fish remains may represent a single deposition and a very limited range of species, showing that fishing focused specifically on certain species. That is interesting and understandable in itself, but it does mean that we may not add up samples representing different species. Only randomly collected remains provide a picture of fishing that is to some extent representative (see Brinkhuizen 2006).
Fig. 14 Ratios of the fish remains from Ypenburg, Wateringen (both collected by hand) and Schipluiden (4-mm sieve).
In this respect there are major differences between the three sites: in all three cases remains were collected by hand, at Ypenburg the soil was also sieved through a 2-mm mesh, at Schipluiden through 4-, 2- and 1-mm meshes, and at Wateringen only one concentration from a pit fill was sieved through a 2-mm mesh. This does however not adequately explain the differences in the sites’ archaeological fish spectra (fig. 14). Flatfish (flounder), eel and Cyprinidae (carp family) were caught at all the sites. Sturgeon and grey mullet were however definitely the most important, not only in numbers of remains, but – considering the fishes’ dimensions – also in economic terms, and precisely in the case of these two species we observe substantial differences: sturgeon was the dominant species at Schipluiden, grey mullet at Wateringen, and Ypenburg occupies an intermediate position in this respect. It is unfortunately difficult, if not impossible, to interpret the numbers of remains of sturgeon (which were up to 3.5 m long at Schipluiden) and grey mullet (up to 60 cm long) in terms of their relative economic importance. An average sturgeon may have yielded 100 times as much meat as a grey mullet, but also produced vast quantities of easily identifiable remains. In this case, too, the differences cannot be attributed to any subtle differences in the sites’ situation and their access to the different ecozones, nor to differences in age. They again reflect real choices made by people in the past.