Title:

Hook disgorgers remove deep hooks but kill fish: A plea for cutting the line

Recreational fishing can result in deep hooking (e.g. in the gullet) of fish that are

intended to be released, leading to the development of various tools intended to as-

sist with hook removal. So-called “hook disgorgers” are typically marketed as being

a mechanism to retrieve the hook while doing so in a way that reduces harm to the

fish, despite there being many studies that demonstrate that it is best to cut the line

for deeply hooked fish. A study was designed to test the effectiveness of six different

hook disgorgers for deeply hooked smallmouth bass, Micropterus dolomieu Lacépède,

captured using baitholder hooks relative to shallow hooked controls and fish for

which the line was cut. Reflex impairment and survival at 10 min, 1 hr and 24 hr were

assessed. The study was terminated after early results revealed that all but one of

the fish that had the hook removed died (n = 17), while all fish that were hooked in

the jaw (n = 4) or had the line cut (n = 5) survived. The ethical conundrum faced by

the research team is discussed here, recognising that an incomplete study would have

less statistical rigour even though it was very clear that disgorgers used when hooks

were in the gullet killed the fish. Stopping rules are common in pharmaceutical trials

and can also be used to inform catch-and-release research to maintain fish welfare.

Best practices for anglers include cutting the line when fish are hooked in the gullet,

and changing fishing strategies and gear type when deep hooking is encountered on

a routine basis, otherwise mortality can be unnecessarily high.