Sound production and sonic apparatus in deep-living cusk-eels (Genypterus chilensis and Genypterus maculatus)

Abstract

A B S T R A C TCusk-eels (Ophidiidae) are known sound producers, but many species live in deep water where sounds are difficult to record. For these species sonic ability has been inferred from inner anatomy. Genypterus (subfamily Ophidiinae) are demersal fishes inhabiting the continental shelf and slope at depths between 50 and 800 m. Males and females G. maculatus have been maintained together in a tank and 9 unsexed specimens of G. chilensis in a second tank, providing a valuable opportunity to record the sounds of living species usually found at great depths. Genypterus chilensis and G. maculatus respectively produced one and two sound types mainly between 7 and 10 pm. Sound 1 in Genypterus maculatus consists of trains of pulses that vary in amplitude and pulse period; call 2 sounded like a growl that results from the rapid emission of pulses that define sound 1. Genypterus chilensis produced a growl having an unusual feature since the first peak of the second pulse has always greater amplitude than all other peaks. These sounds are probably related to courtship behavior since floating eggs are found after night calls. The anatomical structures of the sound-producing organ in both species present an important panel of highly derived characters including three pairs of sonic muscles, a neural arch that pivots on the first vertebral body and a thick swimbladder with unusual features. Sonic structures are similar between species and between sexes. Therefore both biological sexes are capable of sound production although precedent from shallow ophidiids and sonic fishes in general suggests that males are more likely to produce courtship calls. This study reports two main types of information. It demonstrates that two deep-living species are capable of sound production, which is a pioneer step in the acoustic study of deep-sea fauna. Recorded sounds should also help to locate fish in open sea. As these species are currently used to diversify the aquaculture industry in Chile, deeper studies on their acoustic behavior should also help to target spawning period and to identify mature specimens.

New High-Tech Flexible Networks for the Monitoring of Deep-Sea Ecosystems

“…80 This is especially true in the deep sea, where fish sounds have rarely been studied despite the fact that many species possess sonic muscles presumably used in vocalization. 81,82 Although many fishes and invertebrates do not produce purposeful sounds, it is important to understand that incidental sound production may occur upon physiological and behavioral activity (e.g., specific swimming and feeding mode sounds). Those acoustic marks can be used to assess the presence of individuals for a certain species and are therefore being incorporated into PAM monitoring procedures.…”

The unexploited potential of listening to deep‐sea fish

“…Gadiformes, Ophidiiformes and Scorpaeniformes (Ali et al, 2016;Bougis & Ruivo, 1954;Fine et al, 2007Fine et al, , 2018Marshall, 1954;Marshall, 1965;Marshall, 1967;Nguyen et al, 2008;Parmentier, Bahri, et al, 2018;Riera, Rountree, Agagnier, & Juanes, 2020, Table 1). These data support the hypothesis that sound production has evolved independently and sporadically in various lineages, which is in complete accordance with data for shallow water species (Fine & Parmentier, 2015).…”

“…To date, sound production mechanisms and/or sound emission has been reported in deep‐sea resident fish species of five different families (Macrouridae, Ophidiidae, Bythitidae, Dinematichthyidae and Anoplopomatidae) that belong to three different orders; Gadiformes, Ophidiiformes and Scorpaeniformes (Ali et al., 2016; Bougis & Ruivo, 1954; Fine et al., 2007, 2018; Marshall, 1954; Marshall, 1965; Marshall, 1967; Nguyen et al., 2008; Parmentier, Bahri, et al, 2018; Riera, Rountree, Agagnier, & Juanes, 2020, Table 1). These data support the hypothesis that sound production has evolved independently and sporadically in various lineages, which is in complete accordance with data for shallow water species (Fine & Parmentier, 2015).…”

“…In the case of one of the aforementioned families (i.e., Ophidiidae), different studies on species living in shallower waters clearly support that acoustic communication is an important aspect of these species biology, which likely mediates reproductive interactions. Sound production has been reported in the striped cusk‐eel ( Ophidion marginatum , Ophidiidae; Mann, Bowers‐Altman, & Rountree, 1997; Rountree & Bowers‐Altman, 2002 ) and in Roche's snake blenny ( Ophidion rochei Ophidiidae; Kéver, Lejeune, Michel, & Parmentier, 2016; Parmentier, Bouillac, Dragičević, Dulčić, & Fine, 2010) as well as in two species, the red cusk‐eel ( Genypterus chilensis , Ophidiidae) and the black cusk‐eel ( Genypterus maculatus , Ophidiidae), which can inhabit depths between 50 and 800 m (Parmentier, Bahri, et al, 2018). Interestingly, species from coastal and deep waters possess the same kind of sound producing mechanism.…”

“…Deep‐sea fish acoustic communication is still poorly documented (Rountree, Juanes, Goudey, & Ekstrom, 2012; Wall, Rountree, Pomerleau, & Juanes, 2014). However, many deep‐sea species are likely to be able to emit sounds, because they possess the required anatomical structures (Ali, Mok, & Fine, 2016; Bougis & Ruivo, 1954; Fine et al., 2007; Fine, Ali, Nguyen, Mok, & Parmentier, 2018; Marshall, 1965; Marshall, 1967; Nguyen, Lin, Parmentier, & Fine, 2008; Parmentier, Bahri, Plenevaux, Fine, & Estrada, 2018; Table 1). Why would so many species possess sonic mechanisms if not to use them?…”