Griffiths et al.: Fish recolonization in temperate Australian rockpools 



643 



f$ Autumn 



Initial n=81 



C Long-term 

 Initial 1=115 



10 20 30 40 50 60 70 80 



10 20 30 40 50 60 70 80 

 Total length (mm) 



10 20 30 40 50 60 70 80 



Figure 6 



Length-frequency distributions (in 2-mm intervals) for Bathygobius cocosensis caught 

 in the initial samples and after 1 week, 1 month, and 3 months later in the short- 

 term study and caught in the initial sampling and 6 months and 12 months later 

 in the long-term study. Samples were pooled for all sites during the (Al spring and 

 (Bl autumn short-term recolonization studies and for all sites during (C) the long- 

 term recolonization study. Studies were conducted between 7 September 1999 and 

 22 September 2000. Samples sizes are shown. 



For rockpool fish assemblages in southeastern Aus- 

 tralia, a period of one week appears insufficient for 

 recolonization of all species if fish are removed during 

 sampling, whereas intervals of one to three months 

 appear sufficient for rockpool fish assemblages at most 

 Bass Point locations to recolonize to preperturbation 

 levels. It is possible that recolonization times may be 

 decreased if all fish are returned to rockpools immedi- 

 ately after sampling. However, this should not provide 

 a foundation for subsequent studies with other defauna- 

 tion methods, such as anesthetics or ichthyocides. The 

 possible residual effects of these other sampling meth- 

 ods, such as the mortality of mobile and sessile inver- 



tebrates or the residues from chemical anesthetics and 

 ichthyocides are possible factors that may complicate 

 fish recolonization patterns (see Lockett, 1998) and 

 certainly require additional investigation. Nonethe- 

 less, in recolonization studies with chemical sampling 

 methods similar recolonization times as those of the 

 present study were found. For example, recolonization 

 of rockpools defaunated by ichthyocides was shown to be 

 complete within 1 month (Grossman, 1982; Prochazka, 

 1996) and 3 months (Beckley, 1985a; Willis and Rob- 

 erts, 1996; Polivka and Chotkowski, 1998). 



Spatial variability in fish recolonization patterns 

 was not definitive with regard to species composition 



