Table 2: Percent composition by weight of shell, gravel, sand, 

 and silt/clay in surficial sediments (top 1-2 cm) collected with 

 a Smith-Maclntyre grab sampler inside and outside the Little 

 Machias Bay egg bed, July 1987. 



Inside Egg Bed 

 Sample Depth (m) %Shell %Gravel %Sand %Silt/Clay 



35 16 45 4 



32 25 42 2 



21 27 47 4 



77 3 20 1 



34 48 19 



Outside Egg Bed 



80 1 13 6 



57 2 39 2 



15 83 2 



12 80 8 



These results suggest that gravel is an important component 

 of egg substrate, although egg substrate is clearly a mixture of 

 shell fragments, gravel, and sand and can be almost 100% shells. 

 This conclusion could not be reached from analysis of the Ponar 

 samples because of a difference in gear design and performance. 

 The Ponar grab collects a much more disturbed substrate sample 

 than the Smith-Maclntyre grab; only in the Smith-Maclntyre 

 samples was it possible to collect the top 1-2 cm of sediment. 

 Surficial sediments in fact compose the egg substrate, i.e., that 

 portion of the substrate to which the eggs are attached. 

 Additional surficial sediment samples are reguired to test the 

 hypothesis that herring do not deposit eggs on substrates with 

 little or no gravel. Drapeau (1973) reported that herring 

 spawned on Georges Bank in 1970 exclusively on gravel patches 

 devoid of sand. 



Analyses of three samples of egg carpet obtained with the 

 Ponar grab sampler and seven collected by SCUBA divers revealed 

 significant differences in egg density and abundance between the 

 shallow and deep portions of the LMB egg bed (Table 3) . Mean egg 

 density was 35% higher in the deeper water and mean egg abundance 

 was almost twice as high. These results indicate that the egg 

 mat was denser and thicker in deeper water. The range of egg 

 abundance estimates for all 51 sub-samples was 1.2-7.2 million 

 eggs/m 2 with means of 2 . 5 million in the shallower portion of the 

 bed and 4.4 million in deeper water. Multiplication of these two 

 mean egg abundance estimates times the areas of the two portions 

 of the egg bed produced a rough estimate of 3.1 x 10 12 eggs in 

 the entire egg bed (Table 4) . A more conservative estimate based 



270 



