634 



Abstract— Understanding recoloni- 

 zation processes of intertidal fish 

 assemblages is integral for predict- 

 ing the consequences of significant 

 natural or anthropogenic impacts on 

 the intertidal zone. Recolonization of 

 experimentally defaunated intertidal 

 rockpools by fishes at Bass Point, New 

 South Wales I NSW), Australia, was 

 assessed quantitatively by using one 

 long-term and two short-term studies. 

 Rockpools of similar size and position 

 at four sites within the intertidal zone 

 were repeatedly defaunated of their 

 fish fauna after one week, one month, 

 and three months during two short- 

 term studies in spring and autumn i 5 

 months each), and every six months 

 for the long-term study (12 months). 

 Fish assemblages were highly resil- 

 ient to experimental perturbations — 

 recolonizing to initial fish assemblage 

 structure within 1-3 months. This 

 recolonization was primarily due to 

 subadults (30-40 mm TL) and adults 

 i >40 mm TL) moving in from adjacent 

 rockpools and presumably to abun- 

 dant species competing for access to 

 vacant habitat. The main recolonizers 

 were those species found in highest 

 numbers in initial samples, such as 

 Bathygobius cocosensis, Enneaptery- 

 gius rufopileus, and Girella elevata. 

 Defaunation did not affect the size 

 composition of fishes, except during 

 autumn and winter when juveniles 

 (<30 mm TL) recruited to rockpools. 

 It appears that Bass Point rockpool 

 fish assemblages are largely con- 

 trolled by postrecruitment density- 

 dependent mechanisms that indicate 

 that recolonization may be driven by 

 deterministic mechanisms. 



Fish recolonization in temperate 



Australian rockpools: 



a quantitative experimental approach 



Shane P. Griffiths 



Environmental Science 



and 



Institute for Conservation Biology 

 University of Wollongong 

 Wollongong, New South Wales, Australia 

 Present address: CSIRO Marine Research 



233 Middle Street 



Cleveland, Queensland 4163 Australia 

 Email address: shanegnffiIhsacsiro.au 



Ron J. West 



Environmental Science 



University of Wollongong 



Wollongong, New South Wales, Australia 



Andy R. Davis 



Institute for Conservation Biology 



University of Wollongong 



Wollongong, New South Wales, Australia 



Ken G. Russell 



School of Mathematics and Applied Statistics 



University of Wollongong 



Wollongong, New South Wales, Australia 



Manuscript submitted 28 April 2003 

 to thr Scientific Editor's Office. 



Manuscript approved for publication 

 5 May 2004 by the Scientific Editor. 



Fish. Bull. 102:634-647(2004). 



Rocky intertidal fishes are faced with 

 many biotic (competition and food 

 availability) and abiotic (temperature 

 and salinity) factors that can influ- 

 ence their distribution and abundance 

 (Gibson. 1982). Despite occupying a 

 dynamic environment, the fish assem- 

 blages in intertidal rockpools have 

 been widely shown to remain persis- 

 tent through time (Grossman. 1982. 

 1986; Collette. 1986). These commu- 

 nities can also rapidly return to their 

 original state after major or even 

 catastrophic perturbations (Moring, 

 1996). Such resilience is less common 

 among assemblages of invertebrates 

 (Connell, 1972; Astles, 1993) because 

 recolonization of substrata is normally 

 dependent upon successful larval 

 settlement (Paine and Levin, 1981). 

 In contrast, fish can rapidly colonize 

 available habitat by larval recruit- 



ment from the plankton (Willis and 

 Roberts, 1996. Beckley, 2000; Griffiths 

 2003a) but also by the relocation of 

 subadults and adults from adjacent 

 rockpools (Beckley, 1985a; Griffiths, 

 2003a). Under natural conditions rock- 

 pools can be defaunated by events such 

 as hurricanes (Moring, 1996) and, in 

 some regions, by seasonal freezing of 

 rockpool water (Thomson and Lehner, 

 1976; Moring, 1990). These events 

 can create new microhabitats or open 

 existing ones for fish to colonize, and 

 therefore have the potential to change 

 fish assemblage structure. 



Understanding recolonization pro- 

 cesses of intertidal fish assemblages 

 is integral for predicting the conse- 

 quences of natural or anthropogenic 

 impacts on the intertidal community. 

 The role of disturbance and recoloni- 

 zation processes in structuring inter- 



