Author's personal copy Fisheries Research 107 (2011) 272–275 Contents lists available at ScienceDirect Fisheries Research journal homepage: www.elsevier.com/locate/fishres Post-release mortality of angled sand mullet (Myxus elongatus: Mugilidae) Matt K. Broadhurst a,∗ , Paul A. Butcher a , Brian R. Cullis b a Industry and Investment NSW, Fisheries Conservation Technology Unit, National Marine Science Centre, P.O. Box 4321, Coffs Harbour, NSW 2450, Australia b Industry and Investment NSW, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia article info Article history: Received 23 July 2010 Received in revised form 4 November 2010 Accepted 9 November 2010 Keywords: Catch and release Unaccounted fishing mortality Mugilidae Hook and line Post-release survival abstract Grey mullets (Mugilidae) are important to recreational fisheries throughout the developed world. In Australia, several species are angled and then released in large numbers; all with virtually unknown fate. In response to the need for such data to facilitate effective stock management, this study sought to quantify the post-release mortality and key causal factors for sand mullet (Myxus elongatus). A total of 125 fish were conventionally angled, and then released along with 50 controls into floating cages in a south eastern Australian estuary, where they were monitored for four days. Five treatment fish died, providing a non-significant mortality of 4%. The few fatalities were mostly explained by a significant positive relationship with the length of trace (between the float and hook) used, and bleeding during release. While sand mullet appear quite tolerant of catch and release, their welfare nevertheless could be improved through simple changes to fishing strategies. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved. 1. Introduction The family Mugilidae comprises 14 genera and more than 60 species that are globally distributed throughout tropical and tem- perate estuarine and nearshore areas (Thomson, 1997). Their often large abundances, schooling behaviour and accessibility means that mugilids are targeted by commercial and artisanal seiners and gillnetters throughout their range, and by recreational fishers in developed countries (West and Gordon, 1994; Bacheler et al., 2005; Rangel and Erzini, 2007). In Australia, more than 10 mugilids are caught commercially (e.g. Chubb et al., 1981; West and Gordon, 1994; Gray et al., 2005), while at least five species (including yelloweye mullet, Aldrichetta forsteri, bluespot mullet, Valamugil seheli, sand mullet, Myxus elongatus, goldspot mullet, Liza argentea and sea mullet, Mugil cephalus) are also taken by recreational fishers (Henry and Lyle, 2003; Grant, 2008). There are few quantitative data on recre- ational catches, although a national 12-month survey done late last century estimated a total of nearly four million mugilids; ∼50% of which were angled (Henry and Lyle, 2003). Further, owing to a combination of minimum legal sizes (21–25 cm TL) and per- sonal daily quotas (15–60 fish) in most states, more than 25% of these fish were released. While the exact species composi- tion remains unknown, a large proportion of the angled discards probably comprised sand mullet, and especially off south east- ern Australia where this species is often incidentally caught by ∗ Corresponding author. Tel.: +61 2 6648 3905; fax: +61 2 6651 6580. E-mail address: mbroadhurst@nmsc.edu.au (M.K. Broadhurst). anglers seeking sand whiting (Sillago ciliata; Sillaginidae) (Grant, 2008). Despite their abundance, and unlike other important species angled across the same habitats (e.g. yellowfin bream, Acanthopa- grus australis: Sparidae – Broadhurst et al., 1999; sand whiting – Butcher et al., 2006; dusky flathead, Platycephalus fuscus: Platy- cephalidae – Butcher et al., 2008 or luderick, Girella tricuspidata: Kyphosidae – Butcher et al., in press), there is no information avail- able on the fate of released sand mullet. Quantifying any associated so-called ‘unaccounted fishing mortality’ is a necessary prerequi- site for ongoing stock assessments and effective management. Also, irrespective of fatalities, in recent years there has been a growing social impetus to identify and ameliorate any fishing and handling practices that negatively affect the welfare of released fish (Davie and Kopf, 2006). Given the requirements above, and the paucity of relevant infor- mation, our main aim in this study was to estimate the short-term (four days) mortality and key causal factors for sand mullet caught and released by anglers using conventional methods in a south eastern Australian estuary. A secondary aim was to recommend appropriate strategies by which negative impacts to this species might be minimised. 2. Materials and methods 2.1. Catch and release of fish Sand mullet were angled by 11 mostly boat-based fishers during one afternoon (1400–1800) and two morning (0700–1100) ses- sions over two days in the Wooli River (29 ◦ 52 ′ S 153 ◦ 16 ′ E) during 0165-7836/$ – see front matter. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved. doi:10.1016/j.fishres.2010.11.009