Tight lines may save lives
Hall K., Broadhurst M. and Brand C., 2011. Tight lines may save lives. Freshwater Fishing Australia, 108: 44–45.
Over the last 10 years, the Fisheries Conservation Technology Unit of Industry & Investment NSW has been investigating the post-release survival (and main contributing factors) of key species that are angled and released. A common harmful factor observed for most species is the anatomical hook location, with mortalities always greater among fish that are deep hooked than those that are mouth hooked. Previous local and international research has shown that the best method of handling such deep-hooked fish is to simply cut the line. Ideally, however, deep hooking should be avoided in the first place. Several experiments have highlighted ways in which anglers might promote such an outcome for golden perch, and most recently during an experiment with tournament anglers in the Murrumbidgee River.
During the two-day event, 63 golden perch were angled and released into cages or tanks and monitored for three days, along with electro-fished controls. All of the controls survived, compared to only 57% of the angled golden perch; a rate considerably less those during three previous experiments involving catch-and-release events in Copeton Dam (100% survival), Lake Windamere (100%) and Lake Mulwala (74%).
The lower survival of the golden perch during the Murrumbidgee-River tournament was due to a much greater frequency of deep hooking than in the earlier events (46 vs. <4%) and largely attributed to the use of natural baits (94 vs. 34%). An additional contributing factor may have been ‘slack-line’ fishing (when rods are left unattended and fish are free to swallow the baits).
Based on the available research, we conclude that deep hooking in golden perch (and potentially other species) could be reduced if anglers use lures or, if using natural baits, actively fish lines and never leave them unattended. Such simple, pro-active measures could ultimately reduce impacts to important native fish stocks.