Effects of temperature and diet on the growth rate of year 0 oyster toadfish, Opsanus tau

Author Posting. © Marine Biological Laboratory, 2006. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 210 (2006): 64-71.The effects of temperature and diet on the growth of captive year 0 specimens of Opansus tau were examined for two consecutive year classes. The 2001 year class was raised at about 23, 26, or 29°C and provided with live brine shrimp, frozen butterfish and squid, or commercial food pellets (45% protein, 19% fat, and 3% fiber) three times per week. Maximal growth was achieved with the pellet diet, and fish raised at 29°C attained the highest mean wet weight (84.0 g ± 14.6 g SE) and fastest instantaneous relative growth rate (IRGR, 1.79% body weight/d). The 2002 year class was raised on the same pellet diet at 31.5°C and fed 3, 5, or 7 times per week. Although more frequent feedings led to significantly greater mean wet weight in the first half of the year, by month 12 there was no significant difference between the three feeding frequencies. These fish weighed approximately 68g and had an average IRGR of 1.74% body weight/d. The pellet diet during both years was correlated with high survival (> 75%).Support was provided by the Marine Models in Biological Research Program, the University of Minnesota Grant in Aid, the NASA Life Science Fellowship, the MBL Associates Fellowship, and NIH grant DC01837

Directional sound sensitivity in utricular afferents in the toadfish Opsanus tau

© 2015 Published by The Company of Biologists Ltd. The inner ear of fishes contains three paired otolithic end organs, the saccule, lagena and utricle, which function as biological accelerometers. The saccule is the largest otolith in most fishes and much of our current understanding on auditory function in this diverse group of vertebrates is derived from anatomical and neurophysiological studies on this end organ. In contrast, less is known about how the utricle contributes to auditory functions. In this study, chronically implanted electrodes were used, along with neural telemetry or tethers to record primary afferent responses from the utricular nerve in free-ranging and naturally behaving oyster toadfish Opsanus tau Linnaeus. The hypothesis was that the utricle plays a role in detecting underwater sounds, including conspecific vocalizations, and exhibits directional sensitivity. Utricular afferents responded best to low frequency (80-200 Hz) pure tones and to playbacks of conspecific boatwhistles and grunts (80-180 Hz fundamental frequency), with the majority of the units (∼75%) displaying a clear, directional response, which may allow the utricle to contribute to sound detection and localization during social interactions. Responses were well within the sound intensity levels of toadfish vocalization (approximately 140 SPL dBrms re. 1 μPa with fibers sensitive to thresholds of approximately 120 SPL dBrms re. 1 μPa). Neurons were also stimulated by self-generated body movements such as opercular movements and swimming. This study is the first to investigate underwater sound-evoked response properties of primary afferents from the utricle of an unrestrained/ unanesthetized free-swimming teleost fish. These data provide experimental evidence that the utricle has an auditory function, and can contribute to directional hearing to facilitate sound localization

Seasonal and daily patterns of the mating calls of the oyster toadfish, Opsanus tau.

Author Posting. © University of Chicago Press, 2019. This article is posted here by permission of [publisher] for personal use, not for redistribution. The definitive version was published in Van Wert, J. C., & Mensinger, A. F. Seasonal and daily patterns of the mating calls of the oyster toadfish, Opsanus tau. Biological Bulletin, 236(2), (2019):97-107, doi:10.1086/701754.Acoustic communication is vital across many taxa for mating behavior, defense, and social interactions. Male oyster toadfish, Opsanus tau, produce courtship calls, or “boatwhistles,” characterized by an initial broadband segment (30–50 ms) and a longer tone-like second part (200–650 ms) during mating season. Male calls were monitored continuously with an in situ SoundTrap hydrophone that was deployed in Eel Pond, Woods Hole, Massachusetts, during the 2015 mating season. At least 10 vocalizing males were positively identified by their unique acoustic signatures. This resident population was tracked throughout the season, with several individuals tracked for extended periods of time (72 hours). Toadfish began calling in mid-May when water temperature reached 14.6 °C with these early-season “precursor” boatwhistles that were shorter in duration and contained less distinct tonal segments compared to calls later in the season. The resident toadfish stopped calling in mid-August, when water temperature was about 25.5 °C. The pulse repetition rate of the tonal part of the call was significantly related to ambient water temperature during both short-term (hourly) and long-term (weekly) monitoring. This was the first study to monitor individuals in the same population of oyster toadfish in situ continuously throughout the mating season.We thank Emily Cardinal for help with data collection and initial hydrophone setup, the Marine Resources Center at Marine Biological Laboratory for dock space and resources, John Atkins for SoundTrap hydrophone support, and Beth Giuffrida for analysis support. Rosalyn Putland and Jenni Stanley are gratefully acknowledged for coding assistance. We also thank UCSBPSTAT for statistics guidance.We are also grateful to the three anonymous reviewers and the editor for their comments. This study was made possible by National Science Foundation grants IOS 1354745 and DBI 1359230.2020-02-0

Potential role of the anterior lateral line in sound localization in toadfish (Opsanus tau)

Author Posting. © The Company of Biologists, 2018. This article is posted here by permission of The Company of Biologists for personal use, not for redistribution. The definitive version was published in Journal of Experimental Biology 221 (2018): jeb180679, doi:10.1242/jeb.180679.Male oyster toadfish (Opsanus tau) acoustically attract females to nesting sites using a boatwhistle call. The rapid speed of sound underwater combined with the close proximity of the otolithic organs makes inner ear interaural time differences an unlikely mechanism to localize sound. To determine the role that the mechanosensory lateral line may play in sound localization, microwire electrodes were bilaterally implanted into the anterior lateral line nerve to record neural responses to vibrational stimuli. Highest spike rates and strongest phase-locking occurred at distances close to the fish and decreased as the stimulus was moved further from the fish. Bilateral anterior lateral line neuromasts displayed differential directional sensitivity to incoming vibrational stimuli, which suggests the potential for the lateral line to be used for sound localization in the near field. The present study also demonstrates that the spatially separated neuromasts of the toadfish may provide sufficient time delays between sensory organs for determining sound localization cues. Multimodal sensory input processing through both the inner ear (far field) and lateral line (near field) may allow for effective sound localization in fish.This study was funded by the National Science Foundation (IOS 1354745 to A.F.M.). C.A.R. was funded through a Rutherford Discovery Fellowship from the Royal Society of New Zealand and a Marine Biological Laboratory fellowship.2019-05-2

Lateral line sensitivity in free-swimming toadfish Opsanus tau

Author Posting. © The Company of Biologists, 2019. This article is posted here by permission of Company of Biologists for personal use, not for redistribution. The definitive version was published in Journal of Experimental Biology 222(2) (2019): jeb190587, doi:10.1242/jeb.190587.A longstanding question in aquatic animal sensory physiology is the impact of self-generated movement on lateral line sensitivity. One hypothesis is that efferent modulation of the sensory hair cells cancels self-generated noise and allows fish to sample their surroundings while swimming. In this study, microwire electrodes were chronically implanted into the anterior lateral line nerve of oyster toadfish and neural activity was monitored during forward movement. Fish were allowed to freely swim or were moved by a tethered sled. In all cases, neural activity increased during movement with no evidence of efferent modulation. The anterior lateral line of moving fish responded to a vibrating sphere or the tail oscillations of a robotic fish, indicating that the lateral line also remains sensitive to outside stimulus during self-generated movement. The results suggest that during normal swim speeds, lateral line neuromasts are not saturated and retain the ability to detect external stimuli without efferent modulation.Funding was provided by National Science Foundation grants IOS 1354745 and DBI 1359230 and 1659604.2020-01-2

Vessel sound causes hearing loss for hummingbird bobtail squid (<i>Euprymna berryi</i>)

Anthropogenic activity and its associated sounds have been shown to incur adverse effects on the behaviour and physiology of a wide range of aquatic taxa, from marine mammals to fishes. Yet, little is known about how invertebrates detect and respond to anthropogenic sound. The hummingbird bobtail squid (Euprymna berryi) has a short lifespan (< 6 months), grows to sexual maturity around 90 days post hatching and its small size (< 5 cm mantle length) makes the species an ideal candidate to examine potential effects of sound exposure under laboratory conditions. Hearing and behavioural observations were made before, during and after 15 minutes of vessel sound playback, and aural sensitivity curves were determined using auditory evoked potentials. A significant decrease in relative ventilation rate was observed during and post sound exposure. Auditory sensitivity before and after vessel sound exposure was also examined for three different ages: juveniles, mid- and late adults. Baseline audiograms indicated that there was a decrease in aural sensitivity with age. All three age groups showed similar, significantly decreased hearing sensitivity following sound exposure, however auditory sensitivity recovered within two hours. Globally, anthropogenic sounds have become louder and more persistent, therefore there may be limited time for these animals to recover from sound exposure. Given their ecological and economic importance, cephalopods should be considered in management and policy on underwater noise owing to potential adverse effects of anthropogenic sound on behaviour and physiology