Can fear conditioning repel California sea lions from fishing activities?

Abstract

10Marine mammal interactions with fisheries create conflicts that can threaten human safety, 11 economic interests, and marine mammal survival. A deterrent that capitalizes on learning 12 mechanisms, like fear conditioning, may enhance success while simultaneously balancing 13 welfare concerns and reduce noise pollution. During fear conditioning, individuals learn the cues 14 that precede the dangerous stimuli, and respond by avoiding the painful situations. We tested the 15 efficacy of fear conditioning using acoustic stimuli for reducing California sea lion (Zalophus 16 californianus) interactions from two fishing contexts in California, USA; bait barges and 17 recreational fishing vessels. We performed conditioning trials on 24 individual sea lions 18 interacting with bait barges. We tested for acquisition of conditioned fear by pairing a neutral 19 tone with a startle stimulus. Avoidance was strongest in response to the startle stimulus alone, 20 but low when paired with a neutral tone. From actively fishing vessels we tested for fear 21 conditioning by exposing sea lions to a neutral tone followed by a startle pulse, a startle pulse 22 alone, or a no sound control. We conducted playbacks from 146 (including 48 no sound control) 23

A synthesis to understand responses to capture stressors among fish discarded from commercial fisheries and options for mitigating their severity

“…Understanding the extent and nature of predation occurring both during capture and after release can provide important inputs into risk assessments for fisheries. Understanding predation rates [e.g., With newly developed predation tags that can detect when a fish has been eaten (Halfyard et al, )], as well as testing net methods to repel habituated predators (e.g., Schakner, Götz, Janik, & Blumstein, ) are fruitful areas of research that would greatly benefit our understanding of predation and post‐release mortality. Probability of recapture following release and the factors influencing recapture similarly remain unknown, and relatively unstudied, for commercial fisheries.…”

The startle reflex in echolocating odontocetes: basic physiology and practical implications

“…In a study that investigated follow-up responses after repeated startle elicitation, the majority of tested grey seals (Halichoerus grypus) sensitised to the stimulus, exhibited flight responses, developed place avoidance and showed signs of temporary fear conditioning (Götz and Janik, 2011). These findings kindled research interest in the startle reflex in the context of practical applications such as target-specific predator deterrence from farmed fish stocks and fisheries (Götz andJanik, 2015, 2016;Schakner et al, 2017). Furthermore, this reflex arc is relevant for understanding the physiological mechanisms underlying aversive responses to anthropogenic ocean noise in marine mammals (Harris et al, 2018), but empirical data is lacking.…”

The Rules of Attraction: The Necessary Role of Animal Cognition in Explaining Conservation Failures and Successes

“…In ex-situ trials, they showed that it was possible to train the seals to avoid a formerly nonaversive tone (CS) that predicted the aversive ADD sound (US) (Götz & Janik 2011). Schakner et al (2017) aimed to extend the application of fear conditioning to the field, to teach California sea lions (Zalophus californianus) to avoid two types of attractants: commercial live bait barges (where sea lions haul out and eat the bait) and sport fishing boats (where sea lions eat bait and captured fish off hooks). A rapid-onset, broadspectrum sound was designed to elicit an aversive acoustic startle reflex.…”