Figure 2

Macroinfauna biomass in the Silver Pit area of the central North Sea in relation to beam trawling effort. Effort is expressed as the average number of times each year any area of the bottom is swept by beam trawling gear. Macrofauna biomass in mmol (C) m^-2 has been converted from g (wet weight) m^-2 by multiplying by factor of 10. Data from Jennings et al.[10] Preliminary analyses of these data showed that the decline in biomass was due to trawling rather than environmental factors such as depth, mean sediment diameter and sorting coefficient.[19]