Fast and behavior-selective exploitation of a marine fish targeted by anglers.

Josep Alós,Robert Arlinghaus,Rosario Rosselló,Miquel Palmer

doi:10.1038/srep38093

Abstract

Harvesting of wild-living animals is often intensive and may selectively target heritable behavioral traits. We studied the exploitation dynamics and the vulnerability consequences of individual heterogeneity in movement-related behaviors in free-ranging pearly razorfish (Xyrichthys novacula). Using underwater-video recording, we firstly document a fast and high exploitation rate of about 60% of the adult population removed in just few days after the opening of the season. Subsequently, we tagged a sample of individuals with acoustic transmitters and studied whether behavioral traits were significant predictors of the vulnerability to angling. Tagged individuals revealed repeatable behaviors in several home range-related traits, suggesting the presence of spatial behavioral types. The individuals surviving the experimental fishery showed only localized and low-intensity movement patterns. Our study provides new insights for understanding the harvesting pressures and selective properties acting on behavioral traits of recreational fishing. Many fish stocks around the globe are today predominantly exploited by recreational fisheries. The fisheries-induced change in fish behavior described here may be therefore widespread, and has the potential to alter food-webs, profitability of the fisheries and to affect stock assessment by eroding catchability in the long-term.

Highlights

From correlation with life-history traits[19,20]
We used a novel state-space models (SSM) model applied to acoustic tracking data and investigated the individual heterogeneity in behavior and whether the home range behavior shown by individual fish was repeatable, representing a personality trait[25]
Considering the slight temporal fluctuations in fish abundance observed in the control site and the significant decrease observed in the exploited population, we estimated a very rapid and intense exploitation rate of 57% [13.9, 79.2] over just three weeks in the pearly razorfish fishery

Summary

Introduction

From correlation with life-history traits[19,20]. The argument underlying this assumption is that catching a fish with baited hooks, artificial lures, gill nets or traps strongly depends on the behavior-driven encounter probability and the active decision of a fish to attack or ingest the bait/lure or enter the trap or gill net[19]. With the development of fine-scale aquatic telemetry and the development of novel statistical tools applied to movement data such as state-space models (SSM), ecologists have a powerful tool for studying individual behavioral heterogeneity in situ[27] and how it correlates with the vulnerability of exploited wildlife and fishes[23,28]. Harvested animals in systems where encounters with the human predator mainly determines the probability of capture are expected to display smaller home range areas and reduced exploration rates in response to exploitation in agreement with the recently proposed “timidity syndrome”[22]. Empirical evidence demonstrating these predictions are both scant and inconsistent. We tested which individuals were harvested after the opening of the fishing season within a few days using a survival approach, and whether vulnerability to capture was related to the home range behavior

Objectives

Methods

Results

Conclusion