100 years ago the early life history stage, i.e. the embryo and larval stages, was recognised by Hjort (1914) as the ‘critical phase’ of the lifecycle of a fish. Hjort’s ‘critical period hypothesis’ states that the early life history is the critical life stage where the majority of the mortality occurring during the lifetime of a fish species will take place. Therefore, factors that affect survival through these early life stages will help to determine recruitment, year class strength and influence population size with clear implications for both conservation and exploitation management purposes.

 

Many pollution studies in fishes have examined the impacts of exposure on the performance and survival of juvenile and adult fishes. The impacts of sub-lethal levels of pollutant exposure on performance of larval fishes has been less well studied, however, we must not forget the little ones, given their importance as the critical life stage. 

 

There is a growing body of research indicating that exposure to pollutants, e.g. PBTs (PCBs, DDT, Mercury), atrazine, malathion amongst others, through maternal transfer or aqueous exposure during the larval stage can significantly affect the behaviour, physiology and growth of fish larvae. Modelling studies, using Individual Based Models have shown that small changes in survival in larvae exposed to sub-lethal PBT concentrations, as a result of increased predation mortality during the larval phase, could impact on larval cohort survival and recruitment dynamics.  

 

In this workshop we will review the impact of sub-lethal pollutant exposure on the ‘survival skills’, i.e. the behaviours associated with swimming and surviving predation encounters, and on the physiology and growth of fish larvae and examine how IBM models can predict subsequent population-level effects. In addition, experimental approaches to study effects of pollution exposure on fish larvae and transgenerational impacts will be discussed to stimulate further research.