Post‐release survival of recreationally caught snapper, Pagrus auratus, in Port Phillip Bay, south‐eastern Australia

Abstract

Snapper, Pagrus auratus (Forester), is an important recreational species in marine waters of Victoria, Australia. This study estimated survival for compulsorily released undersized P. auratus by holding fish in cages and tanks for 3 days. In all, 620 P. auratus caught by angling were assessed for post-release survival and 200 additional fish were used as controls. The survival rate was greater for shallow-hooked (97%) than deep-hooked (48%) P. auratus. Post-mortems showed that hooking injuries to the throat and/or gill area caused most deaths, while piercing of the heart also caused mortalities. Removing deeply ingested hooks decreased survival. To estimate survival of P. auratus across the Victorian fishery, this studyÕs results should be combined with estimates of shallow-hooking rates in the fishery. Shallow-hooking rate estimates would quantify the impact of the low survival rate found for deep-hooked fish.

Fate of three Australian teleosts after ingesting conventional and modified stainless- and carbon-steel hooks

“…Moreover, all fatalities were much lower than those observed for the three species after being released with their ingested hooks removed (e.g. 58 -88%; Broadhurst et al, 2007;Butcher et al, 2007;Grixti et al, 2010). These results, combined with the rapid resumption of normal feeding (within 1 week), along with the conformity among mean plasma glucose between controls and treatment groups at the end of sampling, provide strong support for cutting the line as a means of minimizing negative impacts associated with hook ingestion (Aalbers et al, 2004;Hall et al, 2009;Butcher et al, 2010).…”

“…Butcher et al, 2006Butcher et al, , 2007Grixti et al, 2010). Moreover, short-term hook-ingested fatalities were fewer when all three species were released with their lines cut than when their hooks were removed with force Grixti et al, 2010).…”

“…Concerns over the potential for at least some mortality and/or negative sublethal impact on angled-and-released mulloway, yellowfin bream, and snapper have led to several quantitative studies being embarked upon (Broadhurst et al, 1999(Broadhurst et al, , 2005Broadhurst and Barker, 2000;Butcher et al, 2007Butcher et al, , 2008Butcher et al, , 2010Grixti et al, 2010). Such work estimated short-term (,10 d) total fatalities of ,23% for mulloway , ,38% for yellowfin bream (Broadhurst et al, 2005;Butcher et al, 2007), and ,33% for snapper (Broadhurst et al, 2005).…”

“…Many fatalities were attributed to the cumulative impacts of several biological, technical, and environmental factors, but anatomical hook location had a dominant effect, manifesting as proportionally more deaths among hook-ingested fish than those caught in the mouth (e.g. Butcher et al, 2006Butcher et al, , 2007Grixti et al, 2010). Moreover, short-term hook-ingested fatalities were fewer when all three species were released with their lines cut than when their hooks were removed with force Grixti et al, 2010).…”

“…In particular, Broadhurst et al (2007) observed a non-significant mortality of 15% for line-cut, hook-ingested fish over more than three months, with 76% of survivors ejecting their hooks after an average of 20 d while maintaining their overall condition. No similar data are available for snapper or mulloway, but during 3 d of monitoring, Grixti et al (2010) recorded 13% hook ejection by similarly treated snapper (n ¼ 59).…”