154 Davey, Upsettins^ the Balance of Nature. [voT! x'xx^n i . 



holes in the fish captured in gill-nets. When these nets are 

 drawn from the sea most of the crabs fall back into the water ; 

 but should any of them fall into the boat, they are thro^vn back 

 into the sea by the fishermen instead of being killed, as they 

 should be. Should an unfortunate gummy be captured, it is 

 at once killed. I am of the opinion that if fishermen made it 

 a practice to return this fish aUve to the water it would greatly 

 assist in keeping in check the legions of crabs that now swarm 

 at the bottom of the Bay, with a resultant improvement to 

 the fish supply. 



In the early days of Portland seals were extremely plentiful, 

 and so also were fish ; yet to-day, because the fisherman observes 

 seals eating fish, he at once blames the seals for any shortage, 

 yet when seals were much more numerous than they are at the 

 present time fish were equally plentiful. The reason for this 

 seeming paradox can. I think, l)e explained as follows : — The 

 pelagic fish spawn on or near the surface of the water, at 

 sufficient distance from land to allow the ova to hatch before 

 wind or tide can cast it ashore. At this time numerous squid 

 (LoUginidae) are busily engaged in devouring the harvest of 

 eggs and young fish, sweeping them up with their long 

 tentacles into their mouths. Now, the seal is especially fond 

 of a squid diet, and this animal also ranges far from land in 

 quest of this food. Thus, the thinning down of the numerous 

 squid by the seals allows most of the spawn to hatch com- 

 paratively untouched, and if 'later, when the fry has grown to 

 larger proportions, the seals take a percentage of them, 

 surely they are entitled to this as a reward for their good offices 

 in affording protection to the ova when it was hatching, and 

 which, without the helj^ of the seals, would have been destroyed 

 in millions by the squid. 



Many other instances could be quoted. It has been demon- 

 strated in England that the more numerous otters were, the 

 more fish there were in the river. 



Some time back I read that in South Australia the fishermen 

 complained to the authorities about the growing scarcity of fish, 

 and blamed the Pelicans, so these were destroyed ; and since 

 their destruction there are practically no fish at all at the 

 place where the Pelicans formerly used to fish, proving con- 

 clusivelv that the Pelicans were not the cause of the trouble. 



Blue Wrens. — Mr. T. Tregellas writes to the Argus "Nature 

 Xotes" (26th January) that when photographing Blue Wrens, 

 Malurus cyaneus, Ellis, during the Christmas holidays, he made 

 the startling discovery that the four young in the nest were being- 

 fed by no fewer than four females and two males. The nest 

 ccntained the third brood for the season. 



