Variable post-release mortality in common shark species captured in Texas shore-based recreational fisheries

Abstract

The practice of catch and release fishing is common among anglers but has been shown to cause unintended mortalities in some species. Current post-release mortality estimates used in coastal shark stock assessments are typically derived from boat-based shark fisheries, which differ from shore-based operations that expose sharks to potentially more stressful environmental and handling conditions. Recreational post-release mortality rates in shore-based fisheries must be quantified to improve stock assessment models and to create guidelines that protect species from overexploitation. Here, we partnered with experienced anglers acting as citizen scientists to deploy pop-up satellite archival transmitting tags (PSAT, n = 22) and acceleration data loggers (ADLs, n = 22). on four commonly caught sharks including the blacktip shark (Carcharhinus limbatus, n = 11), bull shark (Carcharhinus leucas, n = 14), tiger shark (Galeocerdo cuvier, n = 6), and great hammerheads (Sphyrna mokarran, n = 2). Mortality occurred within minutes to hours post-release. If evidence of mortality occurred after normal diving behavior had been re-established for 10 days, then the mortality was considered natural and not related to the catch-and-release process. Post-release mortality estimates ranged from 0% for bull and tiger sharks to 45.5% for blacktip sharks. Of the two great hammerheads, one died within 30 minutes post-release while the other exhibited mortality characteristics 14 days after release. Moribund blacktip sharks experienced on average 3.4–4.9°C warmer water compared with survivors. Recovery periods were estimated for survivors of each species and were highly variable, differing based on duration of tag deployment. High variability in responses to capture and release between species demonstrates the need for species-specific assessments of post-release mortality in shore-based recreational fisheries.

High survivorship of sandbar sharks (Carcharhinus plumbeus) following catch and release in a growing land-based fishery in Massachusetts

“…Furthermore, volunteer fishermen of all experience levels used similar techniques and fishing gear to capture and handle sandbar sharks, and many anglers expressed their intent to minimize fight and handling times however possible. Similar acknowledgement of the need to reduce negative effects of land-based recreational shark fishing has been observed in surveys of land-based shark fishermen in Florida (Guay et al, 2021) and Texas (Gibson Banks et al, 2023). Nevertheless, multiple anglers used J-hooks to capture sandbar sharks, a violation of current Massachusetts state law.…”

“…Similarly, Kilfoil et al (2017) reported low (6%) PRM of sand tigers (Carcharias taurus) caught in Delaware, with all mortality attributed to internal hooking. Most recently, Binstock et al (2023) reported variable, species-specific PRM rates for bull (Carcharhinus Leucas) (7%), blacktip (50%), and tiger (Galeocerdo cuvier) (0%) sharks caught in Texas, with evidence that increasing water temperatures resulted in higher mortality rates for blacktip sharks. Mortality has also been suspected to have occurred in land-based fishing operations because of the removal of sharks from the water (i.e., air exposure) for extended periods during handling (Shiffman et al, 2017).…”

Talk is cheap: Direct evidence of conservation‐based changes in angler behavior

“…From 2018 to 2021, a post‐release mortality study was conducted in conjunction with a subset of Sharkathon tournament participants (Binstock et al, 2023). The study reported on post‐release mortality for four shark species: tiger shark ( Galeocerdo cuvier ), blacktip shark ( Carcharhinus limbatus ), bull shark ( Carcharhinus leucas ), and great hammerhead ( Sphyrna mokarran ), noting that water temperature and fighting behavior increased post‐release mortality of the more sensitive species.…”

“…Anglers participating in catch‐and‐release tagging programs are often well‐informed on the issues of shark conservation and have positive attitudes toward sharks (Gallagher et al, 2017; Mcclellan Press et al, 2016). These anglers also assume that most, if not all, sharks released will survive (Cooke & Schramm, 2007), but research has demonstrated that this is not always the case (Binstock et al, 2023; Ellis et al, 2017). Survival is influenced by numerous factors, including gear used, handling practices, and environmental variables (Bartholomew & Bohnsack, 2005; Binstock et al, 2023; Muoneke & Childress, 1994; Weber et al, 2020).…”

“…These anglers also assume that most, if not all, sharks released will survive (Cooke & Schramm, 2007), but research has demonstrated that this is not always the case (Binstock et al, 2023; Ellis et al, 2017). Survival is influenced by numerous factors, including gear used, handling practices, and environmental variables (Bartholomew & Bohnsack, 2005; Binstock et al, 2023; Muoneke & Childress, 1994; Weber et al, 2020). For example, previous studies on teleosts have shown that keeping gills submerged may help increase the rate of survival after release (e.g., Veldhuizen et al, 2018).…”