418 



Abstract — Data collected during fish- 

 ery-independent sampling programs 

 were used to examine the impact 

 of appendage damage (indicated by 

 lost or regenerated legs and anten- 

 nae) on the reproductive output of 

 female western rock lobster iPanu- 

 lirus cygnus). Most of the damaged 

 females sampled had one (53%), two 

 (27%), or three ( 13% ) appendages that 

 had been lost or that were regenerat- 

 ing. Appendage damage was associ- 

 ated with the reduced probability of 

 a female developing ovigerous setae; 

 and if setae were produced, with the 

 reduced probability that females would 

 produce more than one batch of eggs 

 within a season. These effects were 

 more pronounced as the number of 

 damaged appendages increased. From 

 data collected in 2002, it was esti- 

 mated that the total number of eggs 

 produced by mature females caught in 

 the fishery was significantly reduced 

 (P<0.001) by 3-9% when the impact of 

 appendage damage was included. 



Changes in egg production of 



the western rock lobster iPanu/irus cygnus) 



associated with appendage damage 



Roy Melville-Smith (contact author) 

 Simon de Lestang 



Email address for R. Melville-Smith; rmsmithiaifish.wa.gov.au 



Department ol Fisheries (Western Australia) 

 Western Australian Marine Research Laboratones 

 39 Northside Drive 

 Hlllarys, Western Australia 6025, Australia 



Manuscript submitted 8 September 

 to the Scientific Editor's Office. 



Manuscript approved for publication 

 March 28 2007 by the Scientific Editor. 



Fish. Bull. 105:418-425 (2007). 



Western rock lobster {Paniilir-iis 

 cygnus) are found only off Western 

 Australia, where they form the basis 

 of an intensive commercial fishery 

 (Phillips and Melville-Smith, 2005). 

 One result of the high exploitation 

 rates experienced by western rock 

 lobster (Brown and Caputi, 1985, 

 1986), and other decapod species 

 (Krouse, 1976; Smith and Howell, 

 1987), is the damage sustained by the 

 catch that is returned to the water. 

 Damage, whether caused by aggres- 

 sion between conspecifics trapped in 

 pots, desiccation on board boats before 

 processing, or rough handling during 

 sorting, is generally a combination of 

 dehydration, broken body parts, and 

 the loss of entire appendages. Apart 

 from the mortality of animals due to 

 processing, both the growth rate and 

 fecundity of the surviving animals 

 can be significantly reduced (Davis, 

 1981; Brouwer et al., 2006). Damaged 

 animals appear to reallocate energy 

 stores towards regenerating damaged 

 appendages and away from growth 

 and reproduction (Norman and Jones, 

 1992; Juanes and Smith, 1995; Mari- 

 appan and Balasundaram, 2001). 



In the western rock lobster fishery, 

 sustainability of the resource has 

 been achieved by management regula- 

 tions that include limited entry to the 

 commercial fishery, a closed fishing 

 season from July to mid-November, 

 and return to the water of all lob- 

 sters that are outside the maximum 

 and minimum legal size limits or that 

 are in a breeding condition (i.e., bear- 

 ing ovigerous setae) (Caputi et al., 

 2000; de Lestang and Melville-Smith, 



2006). Anecdotally, these regulations 

 are believed to result in 55% of the 

 P. cygnus catch being returned to the 

 sea. This species is especially suscep- 

 tible to autotomizing (dropping) limbs 

 (Brown and Caputi, 1983, 1985): 

 40-80 tonnes of legs are estimated 

 to be lost from the landed catch of 

 P. cygnus each year (Davidson and 

 Hosking, 2002). 



We used data from a variety of ex- 

 isting and new sources to examine 

 the effect of appendage loss and re- 

 generation (both antennae and legs) 

 on the reproductive biology of female 

 P. cygnus. We believe this study to be 

 the first comprehensive assessment of 

 the impact that appendage damage 

 has on the reproductive output of a 

 decapod species. This study assesses 

 the impact of appendage damage on 

 the proportion of females develop- 

 ing ovigerous setae, the proportion 

 of females that will produce one or 

 more batches of eggs within a breed- 

 ing season, and the number of eggs 

 in a batch. 



Materials and methods 



Sampling regime 



Data were collected during a fishery- 

 independent breeding stock survey 

 (hereafter referred to as "the survey"), 

 which has been conducted annually at 

 three localities (Lancelin, Dongara, 

 and Abrolhos Islands) and intermit- 

 tently at three others (Fremantle, 

 Jurien, and Kalbarri) since 1992. The 

 commercial fishery in Western Aus- 



