Righty Fish Are Hooked on the Right Side of Their Mouths – Observations from an Angling Experiment with Largemouth Bass, Micropterus salmoides

Abstract

The development of muscles and bones in fish is laterally asymmetric (laterality). A "lefty" individual has a "C"-shaped body, with its left-side muscles more developed and the left side of its head facing forward. The body of a "righty" is the mirror-image. This laterality causes asymmetric interactions between individuals of different fish species, in that a righty or lefty fish consumes more lefty or righty fish, respectively. To investigate the coupling mechanisms between body asymmetry and predatory behavior, we conducted angling experiments with largemouth bass (Micropterus salmoides). We used the position of the fishhook set in the mouth to indicate the movement direction of the fish when it took the bait. Righty fish had more hooks set on the right side, whereas lefty fish had more on the left side, indicating that righty fish moved more to the left, and lefty fish moved more to the right, in successful catches. The relationship between the hooked position and movement direction was confirmed by video-image analysis of the angling.

The development and evolution of left‐right asymmetry in invertebrates: Lessons from Drosophila and snails

“…In another marked contrast to primary asymmetry, secondary asymmetry has frequently evolved from symmetry as well as through polarity reversal (Palmer, 2004). Thus, the polarity of the secondary asymmetry is far more variable among species, as in bivalve shells (Odhner, 1919) and flounder eyes (Policansky, 1982), and within species, as in crab claw (Shigemiya, 2003) and fish body shape (Nakajima et al, 2007).…”

Lateralized behavior in the attacks of largemouth bass on Rhinogobius gobies corresponding to their morphological antisymmetry

“…(Ministry of the Environment, Government of Japan, 2004). Morphological antisymmetry occurs in both species (Seki et al, 2000;Nakajima et al, 2007;Yasugi and Hori, 2011), and the predominance of cross-predation has been demonstrated in their predator-prey interaction . Accordingly, we carried out a behavioral test of predation events using these two species, and investigated the interactions between the predatory behavior of bass and the evasive response of goby with respect to their dimorphism.…”

“…However, recent studies in some fishes have demonstrated that the leftward or rightward bias in the behavioral direction of each individual corresponds to morphological asymmetry, specifically antisymmetry (Hori, 1993;Nakajima et al, 2007;Takeuchi et al, 2010;Hata et al, 2011). This antisymmetry is defined as a dimorphism in which one side of the body is structurally and/or functionally more developed than the other side, and is distinguished from fluctuating or directional asymmetry (Palmer and Strobeck, 1986;Palmer, 1996).…”

“…It is predicted that this correspondence between behavior and morphology may result from the favored use of one eye (Takeuchi et al, 2010) or lateralized neuronal circuits for controlling such behavior according to the morphological difference. Antisymmetry has been found in many fishes belonging to seven families in four orders (Mboko et al, 1998;Seki et al, 2000;Hori et al, 2007;Nakajima et al, 2007;Takeuchi et al, 2010;Hata et al, 2011; since its first documented occurrence in the scale-eating cichlids (Perissodus spp.) of Lake Tanganyika (Liem and Stewart, 1976;Hori, 1991;Hori, 1993).…”

“…Some predators have a common bias in approach or attack directions according to their morphological type (lefty or righty), with lefties showing more clockwise or rightward behaviors and righties showing more counterclockwise or leftward behaviors (Hori, 1993;Nakajima et al, 2007;Takeuchi et al, 2012). Similarly, prey may have lateral biases in the direction of their evasive response corresponding to their morphological asymmetry.…”