Herring Roe, Migration, Food. 79 



silvery sheen, appear abundantly among the baiter's catch (see 

 " Whitebait "). In the latter month stow-netting ceases, and the 

 drag-net comes into use. Then and in June and July fishing 

 is carried on from the shore, and fewer big fish got. In a few 

 of the so-called " yawlings," nearly 6 inches long, at the end 

 of May we have found the roe commencing to expand, or in 

 what may be termed the u pinky " or vascular stage, but with- 

 out trace of eggs, similar, in fact, to the conditions met 

 with in December. Whether this indicated a later spawning 

 we are not prepared to say, though other circumstances 

 point to the likelihood of their being among the later autumn 

 spawners. 



Concerning migration, our limited data barely allows a sound 

 conclusion to be drawn. It would appear, though, as if they 

 were to a certain extent local in habitat. Except when the ripe 

 adults shoal and go seawards in the spring breeding season 

 those of the yawling stage apparently are resident hither and 

 thither in various parts of the estuarine area nearly all the year 

 round. 



Their food within the estuary depends somewhat on age and 

 season. Among the younger fish the stomach often appears 

 empty, or the contents, of a gelatinous consistence, are not de- 

 finitely recognisable. In some, though, by the aid of the 

 microscope, we have detected remnants of minute crustaceans 

 Ostracods, Copepods, Amphipods and Mysidae, as well as Crab- 

 Zoea (early swimming stage), and embryos of tiny soft-bodied 

 Mollusks that creep among the Zostera weed. In many older 

 fish, likewise, gelatinous residue is all that can be seen, for the 

 yawling and adult herring's rapid digestion of tender material 

 soon reduces most of their food to a pulp. This has given rise 

 to the fishermen's notion that the herring " lives on suction." 

 Certainly the North Sea tidal wave brings up stream myriads of 

 the diminutive Crustacea mentioned above. 



But the so-called " yawlings," from a few inches up to the 

 adult herrings, by no means confine their diet to these, for we 

 have found stuck in their throats and in the stomach their 



