It has been speculation of mine for some time that blackfish have a way of repopulating a stream relatively quickly they must be able to do this to survive the boom and bust of the Australian climate and it could be that the ratio of  females to  males is high this would allow a single male to fertilise  more than one females nest however this would mean that the male does not stay with the eggs at least not on a permanent basis he may be called on from time to time to defend a nest from intrusion including from people/ researches this could have been the reason researches believed that the males stayed with the eggs.

for this reason I am adding more nesting boxes to my ponds and also to accommodate maturing females who will lay eggs for the first time this year, the breeding season starts in around two weeks and I will be ready.