It is difficult to predict how long a battered stock will take to recover as the juvenile fish population swings after survival. Colin Minto at Dalhousie University in Halifax, Nova Scotia, Canada, explained that data from different fisheries showed that depleted fish stock takes long time to recover.
Minto’s team analysed that the juvenile fish behave very differently. They said that at very low population sizes, the number of fish that survive to adulthood falls off steeply. According to Minto the fall-off in numbers is thought to result from the failure of adult fish in depleted stocks to find mates or fend off predators.
Minto revealed that new thing is that the survival of juveniles depends on the density of the adult population over the whole range of population sizes and in many different species. As per a new study the survival of juveniles is less variable when adult populations are numerous, because the adults seem to damp down these yearly variations.
Minto also said that with the growth of population the number of surviving juveniles becomes fewer for each adult fish that spawns because the juveniles compete with the adults for space and food, and may even be eaten by them. He further explained that as the numbers of adults are low there is less of this damping so the number of juveniles that survive each year becomes highly variable.
