Fisheries Research xxx (2006) xxx–xxx The effects of appendage loss on growth of South African west coast rock lobster Jasus lalandii Stephen L. Brouwer ∗ , Johan C. Groeneveld, Bradley Blows Department of Environmental Affairs and Tourism, Marine and Coastal Management, Private Bag X2, Rogge Bay 8012, South Africa Received 24 May 2005; received in revised form 11 November 2005; accepted 21 November 2005 Abstract Capture by traps, sorting by fishers and discard of lobsters smaller than a minimum legal size (MLS) may induce physical injuries, such as loss of appendages, which can reduce somatic growth rates and population productivity. Heavily fished populations of rock lobster Jasus lalandii off western South Africa are prone to physical injuries, we investigated the extent of and effects on growth of various degrees of appendage loss. Lobsters injured by removal of legs, feeding legs or antennae were kept in cages at sea until moulting, and their subsequent growth and recovery of appendages monitored. Incidence of injury in wild populations was recorded by observers on lobster fishing vessels at sea. Growth decreased significantly following the loss and re-growth of ≥3 appendages, mortality rate increased, and injured lobsters moulted earlier than uninjured individuals. Five to 9% of trap-caught lobsters had missing appendages, although most of these (80%) had only one or two missing appendages. Most multiple injuries were found in lobsters larger than the MLS. The proportions of injured male and female lobsters in commercial catches declined sharply during the moulting season, but increased gradually thereafter coincident with rising cumulative fishing effort. The low relative estimate of appendage loss suggests that regulations to reduce injuries are effective. © 2006 Elsevier B.V. All rights reserved. Keywords: Lobster; Growth; Injury; Jasus; Recruitment; Fishery 1. Introduction Capture, handling and release of undersized lobsters in commercial trap-fisheries may cause sub-lethal physiolog- ical damage as a result of air-exposure (Vermeer, 1987; Taylor et al., 1997; Taylor and Waldron, 1997) and physi- cal damage such as loss of appendages (legs or antennae) through autotomy (Brown and Caputi, 1985). Surviving lob- sters typically regenerate lost appendages, although this pro- cess incurs a long-term functional cost, such as reduced foraging efficiency, mating success, and increased vulnera- bility to predation (Juanes and Smith, 1995). Replacement of lost appendages at a subsequent moult will also affect the animal’s energy budget, and many studies have high- lighted associated reductions in somatic growth, or changes in intermoult duration (Bennett, 1973; Chittleborough, 1975; Davis, 1981; Brown and Caputi, 1985; Juanes and Smith, ∗ Corresponding author. Tel.: +27 21 402 3034; fax: +27 21 421 7406. E-mail address: Sbrouwer@deat.gov.za (S.L. Brouwer). 1995). The prevalence of appendage loss in decapod crus- tacean populations is consistently high (Scarratt, 1973; Krouse, 1976; Shirly and Shirly, 1988; Powell et al., 1998; Mathews et al., 1999; Bottari et al., 2003) and can potentially affect population dynamics and commu- nity processes. This is especially so for heavily exploited populations, because contact with fishing gear and han- dling by fishers may increase the prevalence of appendage loss (Brown and Caputi, 1985; Schoeman et al., 2002a, 2002b). Managers of many crustacean trap fisheries have intro- duced escape vents of various sizes and shapes as they allow undersized specimens to escape before traps are brought to the surface (Krouse, 1989; Miller, 1990; Everson et al., 1992; Treble et al., 1998; Groeneveld et al., 2005), thereby indirectly reducing injuries. Although use of escape vents reduces the retention of undersize lobsters, sometimes by >50% (Phillips et al., 2000), physical injuries caused by han- dling remain a concern in major fisheries for Jasus lalandii (Schoeman et al., 2002a), Panulirus cygnus (Phillips et al., 0165-7836/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.fishres.2005.11.017 FISH-2029; No. of Pages 7