Sound production in marbled rockfish (Sebastiscus marmoratus) and implications for fisheries

Recently,several rockfish species(genus Sebastes)have been reported to be soniferous.To determine whether an additional rockfish species produces sounds,passive acoustic recordings were analyzed from captive marbled rockfish(Sebastiscus marmoratus)during the non-spawning season.Three distinct sounds were identified based on frequency features.The common characteristics among all sounds were low frequency(below 300 Hz)and rapidly dampened pulses consisting of 3–5 acoustic energy cycles.During free-swimming conditions in the canvas tank,the fish produced voluntary sounds with lower frequencies than the disturbance sounds produced by individuals during prodding.Two types of sounds were identified in the disturbance context:one type consists of single or double pulses with two peak frequencies,and another type consists of a series of pulses with a single peak frequency.These results suggest that specific-species and behavior-associated sounds are potentially useful in passive acoustical surveys to monitor rockfish populations and distributions remotely.

A study on sound production acoustics in the black cicada(C.atrata Fabricius)

The long rib of the sounding membrane in the black cicada is an analog to the beam clamped at one end. The fundamental frequency of activation sound is between 3900-5500 Hz and is basically consistent with the possible range of the main peak frequency ( MPF) of song in the black cicada. The operculum (Op), tymbal cover (TC) and joint membrane (JM)are respectively analogous to a unifor square plate clamped at one edge and free at the others, to another plate at two opposite sides and free at the other, and to a rectangular membrane clamped at four sides. The fundamental frequencies of activated vibration are basically consistent with theMPFs and main high frequency components of vibrations of the Op, TC and JM, respectively.The resonant cavity and spiracles on both sides are analogous to a current resonace circuit and to a resistance connected in parallel at the output ends, and the resonant frequency and quality factor of the circuit are in good agreement with the MPF and its tuning sharpness of son the black cicada.

Potential impacts of shipping noise on Indo-Pacific humpback dolphins and implications for regulation and mitigation:a review

Shipping noise is a widespread and relatively loud sound source among human-induced underwater sounds.The impacts of shipping noise are of special concern for Indo-Pacific humpback dolphins(Sousa chinensis),as they inhabit shallow and nearshore habitats and are highly dependent on sound for survival.This study synthesizes our current understanding of the potential impacts of shipping noise on Indo-Pacific humpback dolphins combined with knowledge on sound production and hearing of these animals and the impacts of noise on other whales and dolphins.For further protection and management of Indo-Pacific humpback dolphins and their habitats,shipping noise should be regulated and mitigated to modify sound from ships,to reduce overall noise levels,and to set more marine protected areas(MPAs)covering most Indo-Pacific humpback dolphin habitats with seasonal and geographical restrictions to avoid ensonification of shipping noise.The emphasis for future research should be on obtaining more baseline information about the population distribution,sound production,hearing capabilities at the population level,behavior,and stress hormones of the humpback dolphins under different noise conditions or under different noise-producing activities,and/or in high-noise areas compared with relatively quiet areas,and the noise characteristics of ships of different types,sizes and speeds.