Full Description

"As with alewife, sound production occurred after the individual had returned to the bottom, or to a level swimming location above the bottom. We did not observe air release during sound production but cannot rule out the possibility due to the difficulty of observing individuals in the limited visibility at dusk and the limited video field of view. White sucker sounds were only heard after a surface event just prior to or after sunset."

"Groups of spawning individuals did not exhibit either the air gulping or sound production behaviors even at sunset in contrast to the non-spawning individuals located a short distance away (< 20 m) within the mill pool."

"White sucker produced 3 to 11 loud “snort” sounds (mean = 7) with a latency of 2.6 s after the surface event, and a mean fish sound series duration of 16.75 s (Fig 5A–5E, Table 1, S2 Audio). Snorts occurred in all white sucker sound series, while snitches occurred in 33% (Table 2). Surface event sounds were detected in 92% and bubble sounds in 58% of the sound series. Snorts had a mean peak frequency of 1,954 Hz, mean bandwidth of 12,285 Hz, and duration of 0.175 s (Fig 5B and 5D; Table 3), while snitches had a mean peak frequency of 2,291 Hz, bandwidth of 10,348 Hz, and duration of 0.083 s (Fig 5C and 5E; Table 3). Bubbles sounds had a mean peak frequency of 1,548 Hz, bandwidth of 2,794 Hz, and duration of 0.014 s (Table 4, Fig 4C). FRT-like sounds occurred in 8% of the sound series (Table 2). No overt reaction of conspecifics was observed to white sucker sounds, but observations were hampered by low visibility and large separation distances among individuals."

Observation Environment Quotes

"Behavior of white sucker was monitored over about 16 h (958 min) across 11 dates at the Stony Brook Herring run, and for an additional 7.5 h (450 min) during spawning events at the Stony Brook Herring run and Webber Pond sites (S1 Appendix). "

"Fig. A.1. Sampling locations. A Mill Creek Herring Run in Marston Mills, Massachusetts (alewife); B Seven Mile Brook just below Webber Pond Dam (alewife) in Vassalboro, Maine; C the nearby Webber Pond Herring Run (alewife), D and the adjacent Webber Pond shoreline (white sucker); in Brewster, Massachusetts; E the mill pool in the Stony Brook Herring Run located in Brewster, Massachusetts (alewife and white sucker), F Stony Brook stream just above the mill pool in the Stony Brook Herring Run; G Brook and Brown trout raceways, and rainbow trout pools (not shown) at the Blue Stream Aquaculture trout hatchery in Barnstable, Massachusetts; H Presumpscot River below Sebago Lake in North Windham, Maine. These photographs provide perspective on the spatial layout of the sampling locations, the equipment setup used, and the potential for species identification. Potentially identifiable bystanders in some panels have been obscured."

Behaviour Description Quotes

"No overt reaction of conspecifics was observed to white sucker sounds, but observations were hampered by low visibility and large separation distances among individuals."

Sound Name Quotes

"Table 2. Most common sounds.' 'The results of this study, and the qualitative comparisons of previously reported FRT sounds, reveal a diverse array to the form of FRT-like sounds. In general, FRTs consist of an initial broadband burst pulse where ticks are too close to resolve, followed by a train of ticks with a decaying tick interval and tick bandwidth. However, the initial broadband burst is not always present, and the tick train can be either very fast and short in duration (e.g., the VFRT), or long (as much as 10 s or more). It is also likely that some of the burst pulse sounds we have observed are FRTs that lack the tick train."

"All six species observed during this study occasionally produced FRT sounds similar to herring, however, other types of air movement sounds were far more prevalent (including the VFRT). "

"We use the term “air movement” sound to include a diverse array of sounds sometimes referred to as “air passage” or “pneumatic” sounds that arise from a variety of mechanisms involving internal air movement, and sometimes external air release, in physostomous fishes (e.g., [6–9])."

Full Description

"Alewife were frequently observed to make a series of sounds after rising to the surface to gulp air (Fig 2A, S1 Audio, S1 and S2 Videos). Individuals would make a rapid dash to the surface and create a small splash, occasionally jumping, as they gulped air. They then rapidly dove to resume swimming at the same depth they started from. Sounds were primarily produced after resuming their previous swimming depth. Of 54 surfacing events recorded in field notes, 34 (63%) were followed by sound production. In many cases silent bubbles escaped from the mouth and gills during the initial descent from the surface. However, once the fish sounds began, a faint “pop” sound could sometimes be detected as one or more bubbles escaped from the gills after each sound. On a few occasions, a sound series concluded with a loud pop as a single large bubble was released from the mouth (Fig 2A, S1 Video). The bubble sounds were difficult to detect and were distinct from high frequency burst sounds produced by the alewife which were labeled “coughs” and “snitches”. Although the cough and snitch sounds were associated with air bubble release, air bubble release alone did not produce them."

"Alewife sound series had an average of 5.9 fish sounds (range 1–16) and a mean fish sound rate of 2.47 sounds/s (Table 1). Alewife surface event series duration averaged 5.39 s while the latency before sound production ranged from 0.35 to 4.14 s and averaged 1.19 s. The most frequently occurring sounds in an alewife sound series (Table 2) were the “cough” (91%) and “snitch” (21%). Air bubbles were not included as part of the sound series but were acoustically detected in 20 series (61%) and occurred an average of 0.36 s after each cough or snitch (range 0.026–0.986 s, standard error = 0.034 s). Coughs had a mean peak frequency of 1,258 Hz, bandwidth of 3,609 Hz and duration of 0.043 s (Fig 2A, 2B and 2D, Table 3). Means (and standard error of the mean) of selected acoustic parameters measured for the most common sound types for each species (1094 sounds out of 1197). Characteristics of the air gulp event (surface splash or jump) and individual bubble release sounds are also provided. FRT = fast repetitive tick, VFRT = very fast repetitive tick. The much less frequently observed snitches (Fig 2C and 2E) had a similar bimodal frequency structure, but were weaker and shorter in duration. FRT-like sounds (examples in Fig 3A and 3B) occurred in only 9% of the sound series (Table 2) and were characterized by a longer duration (mean = 1.3 s) and higher frequency (mean peak frequency = 6,254 Hz, Table 3). Bubble sounds (example Fig 4B) had a higher peak frequency (mean = 1,716 Hz), and shorter duration (mean = 0.009 s), than the coughs and snitches (Fig 2A, Table 3)."

"The most frequently recorded alewife sounds in this study were the “cough” and “snitch”. The cough trains produced by alewife after gulping air (Table 4) are not similar to sounds reported for other clupeiform fishes which typically primarily produce FRTs [5, 7–8, 19]. However, alewife do occasionally (9% of the sound series) produce FRT sounds similar to those reported for Clupea spp. and Sardinops sagax. Although the mechanism by which the cough and snitch sounds are produced is uncertain, it appears that each cough is produced within the pharyngeal or branchial chambers just prior to emission of one or more gas bubbles from one or both gill covers. However, it is clear that release of gas through the gills or mouth alone does not produce sounds similar to either the coughs, snitches or FRTs (compare S1 and S2 Videos exhibiting strong cough sounds, with S3 and S4 Videos where bubbles are released with almost no detectable sound)."

"Although we did not observe overt reactions of conspecifics to alewife sounds, the sounds were well within the species’ hearing range [21–23]. The observations that sounds are only produced after some air gulp events could be interpreted as possible evidence for voluntary sound production, or it could simply be that the fish sometimes has to expend more effort to expel the gas (i.e., it is literally an involuntary cough to expel gas trapped within the gill chamber)."

Observation Environment Quotes

"While conducting a pilot survey of the soundscapes of freshwater habitats in five regions of New England in the spring of 2008, we recorded possible air movement sounds likely produced by alewife (Alosa pseudoharengus, Clupeidae) and various species of unidentified salmonids [4]."

"Over 30 h of observations (1,857 min) were made of alewife behavior (S1 Appendix), however to reduce the possibility of inclusion of sounds from blueback herring (Alosa aestivalis, Clupeidae), we excluded sound data collected after May 2 from the measurement data. Alewife observations were usually done during the afternoon daylight hours through the early evening. Typically, from a few to a dozen or more individuals occupied the observation chambers at any given time in both the Mill Creek and Webber Pond raceways as they rested prior to moving into the adjacent ponds."

Behaviour Description Quotes

"Although we did not observe overt reactions of conspecifics to alewife sounds, the sounds were well within the species’ hearing range [21–23]. The observations that sounds are only produced after some air gulp events could be interpreted as possible evidence for voluntary sound production, or it could simply be that the fish sometimes has to expend more effort to expel the gas (i.e., it is literally an involuntary cough to expel gas trapped within the gill chamber)."

Sound Name Quotes

"While conducting a pilot survey of the soundscapes of freshwater habitats in five regions of New England in the spring of 2008, we recorded possible air movement sounds likely produced by alewife (Alosa pseudoharengus, Clupeidae) and various species of unidentified salmonids [4]."

"We use the term “air movement” sound to include a diverse array of sounds sometimes referred to as “air passage” or “pneumatic” sounds that arise from a variety of mechanisms involving internal air movement, and sometimes external air release, in physostomous fishes (e.g., [6–9])."

"Table 2. Most common sounds."

"The results of this study, and the qualitative comparisons of previously reported FRT sounds, reveal a diverse array to the form of FRT-like sounds. In general, FRTs consist of an initial broadband burst pulse where ticks are too close to resolve, followed by a train of ticks with a decaying tick interval and tick bandwidth. However, the initial broadband burst is not always present, and the tick train can be either very fast and short in duration (e.g., the VFRT), or long (as much as 10 s or more). It is also likely that some of the burst pulse sounds we have observed are FRTs that lack the tick train."

"All six species observed during this study occasionally produced FRT sounds similar to herring, however, other types of air movement sounds were far more prevalent (including the VFRT)."

Full Description

"Brook trout sounds were infrequent despite the high stocking density in the raceway. Only 6 sound series with one to three fish sounds and a 6 s latency, were positively identified due to the high fish density and limited camera field of view in the raceway (Tables 1 and 2, Fig 6A, S3 Audio). Fish were observed to surface and expel air from gills as they descended followed by sounds after the fish had returned to the bottom, or its original swimming position in the water column. Gas release was not observed in association with sounds but cannot be ruled out due to the difficulty of following individuals after the air gulp event. The most frequently observed sound was a short duration FRT-like sound we term a “Very Fast Repetitive Tick” (VFRT) with a mean peak frequency of 4,993 Hz, bandwidth of 10,407 Hz, and duration of 0.096 s (Tables 2 and 3, Fig 6B and 6D). The next most common sound was named a “snitch” which had similar properties as the VFRT except for a narrower bandwidth of 5,166 Hz and more burst-like waveform lacking the repetitive ticks (Tables 2 and 3, Fig 6C and 6E)."

Observation Environment Quotes

"Recording within single species raceways at the Blue Stream Aquaculture insured that sounds could confidently be attributed to each of the three trout species (i.e. brook trout, brown trout or rainbow trout)."

"Field observations were made on wild fish in seven locations within Massachusetts and Maine, and on captive fish held in semi-natural conditions at the Blue Stream Aquaculture facility in Barnstable, Massachusetts (detailed description of sampling locations and methods are provided in S1 Appendix)."

Behaviour Description Quotes

"No overt reaction of conspecifics to fish sounds was observed."

Sound Name Quotes

"Table 2. Most common sounds.' 'The results of this study, and the qualitative comparisons of previously reported FRT sounds, reveal a diverse array to the form of FRT-like sounds. In general, FRTs consist of an initial broadband burst pulse where ticks are too close to resolve, followed by a train of ticks with a decaying tick interval and tick bandwidth. However, the initial broadband burst is not always present, and the tick train can be either very fast and short in duration (e.g., the VFRT), or long (as much as 10 s or more). It is also likely that some of the burst pulse sounds we have observed are FRTs that lack the tick train."

"All six species observed during this study occasionally produced FRT sounds similar to herring, however, other types of air movement sounds were far more prevalent (including the VFRT). "

"We use the term “air movement” sound to include a diverse array of sounds sometimes referred to as “air passage” or “pneumatic” sounds that arise from a variety of mechanisms involving internal air movement, and sometimes external air release, in physostomous fishes (e.g., [6–9])."

Full Description

"Fig 4. Comparison to bubble sounds. Waveforms of individual air bubble sounds, and individual FRT ticks are compared on the same 500 ms time scale after filtering around 500 Hz to 6000 Hz (amplitudes are relative and not directly comparable). (A) Single bubble from bottom sediment gas seep, (B) single bubble from alewife gills, (C) single bubble from white sucker, (D) two ticks from an alewife FRT, (E) three ticks from a rainbow trout FRT, (F) three ticks from a brown trout bubble FRT, (G) multiple ticks from a brown trout VFRT, and (H) four ticks from a Pacific herring FRT."

Full Description

"The unidentified salmonid sounds recorded from the Presumpscot River are provisionally attributed to landlocked Atlantic salmon (Salmo salar, Salmonidae) which are abundantly stocked at the sampling location. The attribution to Atlantic salmon is supported by similarities with other salmon species and significant differences with the three trout species. The qualitative description of salmon sounds (Salmo and Oncorhynchus) provided by Neproshin and Kulikova [17] were similar to the unidentified salmonid sounds. They reported that salmon make sounds in the form of splashes when emerging from the surface followed by croaking, rumbling and whistle (similar to our moan) noises from air passage."

"At dusk, unidentified salmonids began to periodically jump creating a loud splash followed by gurgle sounds and an unusual moan sound. Individuals observed while it was still light appeared to be salmonids but could not be positively identified. Jumps and associated sounds increased in frequency after dark. Surface events were exclusively jumps and were acoustically detected in 85% of 41 detected sound series (Tables 1 and 2). Sound event series were characterized by an average of 2.9 sounds after a 1.6 s latency (Table 1, Fig 9A, S6 Audio). Gurgle (63%) and moan (34%) sounds were the most frequently observed sound types and had mean peak frequencies of 748 Hz and 962 Hz, respectively (Tables 2 and 3, Fig 9). Bubble sounds were detected in 24% of the sound series (Table 2)."

"Further, although brook trout were also abundant at the Presumpscot River site, the behavior and sounds of captive trout were different from those observed for the unidentified salmonid. First, the dramatic moan sounds were unique to fish in the river. Second, the gurgle sounds produced by rainbow trout were of significantly higher frequency than the unidentified salmonid gurgles, and rainbow trout are not stocked in the river. Lastly, there was a clear change in behavior of the unidentified salmonid at dusk with individual fish beginning to jump."

Observation Environment Quotes

"The Presumpscot River is heavily stocked with brook and brown trout as well as landlocked Atlantic salmon (Salmo salar, Salmonidae) in the spring, and the recording location is a popular fly fishing site, but numerous other species may have been present. Sounds were attributed to unknown salmonids only when they followed jumps or surface gulps."

Sound Name Quotes

"The unidentified salmonid sounds recorded from the Presumpscot River are provisionally attributed to landlocked Atlantic salmon (Salmo salar, Salmonidae) which are abundantly stocked at the sampling location. The attribution to Atlantic salmon is supported by similarities with other salmon species and significant differences with the three trout species. ' 'Table 2. Most common sounds.' 'The results of this study, and the qualitative comparisons of previously reported FRT sounds, reveal a diverse array to the form of FRT-like sounds. In general, FRTs consist of an initial broadband burst pulse where ticks are too close to resolve, followed by a train of ticks with a decaying tick interval and tick bandwidth. However, the initial broadband burst is not always present, and the tick train can be either very fast and short in duration (e.g., the VFRT), or long (as much as 10 s or more). It is also likely that some of the burst pulse sounds we have observed are FRTs that lack the tick train."

"All six species observed during this study occasionally produced FRT sounds similar to herring, however, other types of air movement sounds were far more prevalent (including the VFRT). "

"We use the term “air movement” sound to include a diverse array of sounds sometimes referred to as “air passage” or “pneumatic” sounds that arise from a variety of mechanisms involving internal air movement, and sometimes external air release, in physostomous fishes (e.g., [6–9])."

Full Description

"Brown trout were stocked at a similar density to the brook trout but produced many more sounds. Air gulping and sound production appeared to increase at dusk. Typically, individuals would rise slowly from a bottom resting position, or midwater swimming position, before accelerating slightly to gulp air usually producing little splash or sounds."

"Diffuse streams of air bubbles of varying size could sometimes be observed escaping from the mouth and gills as the fish descended, but such gas release usually did not produce detectable sounds (example S5 Video). However, a unique sound we term a “gill-bubble FRT” was recorded on several occasions simultaneously with bubble release as a brown trout dove from the surface (Fig 7A, S4 Audio, S6 and S7 Videos). Unlike the diffuse bubble streams usually observed during the dive for brown trout, as well as all other species, the FRT-like sound was produced by uniform sized bubbles in a single file that rapidly streamed from either the right or left gill cover, but not both. Shortly after settling, individuals were sometimes observed to simultaneously release one to a few bubbles from each gill, often with a yawn which may have been coincident with VFRT sound production. We refer to this event as a “double gill bubble release”. One individual was observed to surface and produce sounds twice within a 45 s period. Brown trout sound series averaged 2.2 fish sounds, a 3.3 s latency, and were 1.3 s in duration (Table 1, Fig 7A, S4 Audio, S6 and S7 Videos). A well-defined VFRT was the most frequently occurring sound occurring in 96% of the sound series (Fig 7B and 7D, Table 2), and was characterized by a mean peak frequency of 4,582 Hz and bandwidth of 9,692 Hz (n = 216, Table 3). In several instances, the VFRT appeared to be produced just prior to the double gill bubble release event, but more data are needed to confirm this. A bird-like chirp (Fig 7C and 7E) was the second most frequent sound (27%) in the brown trout series (Table 2) and had a peak frequency of 4,760 Hz (n = 9, Table 3). It should be noted that simultaneous recording with a microphone confirms the bird-like chirp sound is produced underwater and not from an aerial source. Bubble sounds were acoustically detected in only 4% of the brown trout sound series (Table 2), and had a mean peak frequency of 1,031 Hz, bandwidth of 9,430 Hz, and duration of 0.016 s (Table 3)."

Observation Environment Quotes

"Recording within single species raceways at the Blue Stream Aquaculture insured that sounds could confidently be attributed to each of the three trout species (i.e. brook trout, brown trout or rainbow trout)."

"Field observations were made on wild fish in seven locations within Massachusetts and Maine, and on captive fish held in semi-natural conditions at the Blue Stream Aquaculture facility in Barnstable, Massachusetts (detailed description of sampling locations and methods are provided in S1 Appendix)."

Behaviour Description Quotes

"No overt reaction among conspecifics to brown trout sounds were observed."

Sound Name Quotes

"Table 2. Most common sounds.' 'The results of this study, and the qualitative comparisons of previously reported FRT sounds, reveal a diverse array to the form of FRT-like sounds. In general, FRTs consist of an initial broadband burst pulse where ticks are too close to resolve, followed by a train of ticks with a decaying tick interval and tick bandwidth. However, the initial broadband burst is not always present, and the tick train can be either very fast and short in duration (e.g., the VFRT), or long (as much as 10 s or more). It is also likely that some of the burst pulse sounds we have observed are FRTs that lack the tick train."

"All six species observed during this study occasionally produced FRT sounds similar to herring, however, other types of air movement sounds were far more prevalent (including the VFRT). "

"We use the term “air movement” sound to include a diverse array of sounds sometimes referred to as “air passage” or “pneumatic” sounds that arise from a variety of mechanisms involving internal air movement, and sometimes external air release, in physostomous fishes (e.g., [6–9])."

Full Description

"Unlike brown and brook trout, surface events were acoustically detected for all sound series (N = 42, Tables 1 and 2). Rainbow trout sound series averaged 1.93 fish sounds, a duration of 1.1 s, and a latency of 1.7 s (Table 1, Fig 8A, S5 Audio). The most frequently observed sound was described as a “gurgle” which occurred in 55% of the series (Table 1), and had a peak frequency of 2,409 Hz, bandwidth of 2,468 Hz, and duration of 0.34 s (Table 3, Fig 8A– 8D, S5 Audio). A VFRT similar to that observed in brook and brown trout occurred in 17% of the series (Table 2, Fig 8C and 8E), and had a mean peak frequency of 4,199 Hz, mean bandwidth of 10,686 Hz, and mean duration of 0.13 s (Table 3). No bubble release was observed for any sound type."

Observation Environment Quotes

"Recording within single species raceways at the Blue Stream Aquaculture insured that sounds could confidently be attributed to each of the three trout species (i.e. brook trout, brown trout or rainbow trout)."

"Field observations were made on wild fish in seven locations within Massachusetts and Maine, and on captive fish held in semi-natural conditions at the Blue Stream Aquaculture facility in Barnstable, Massachusetts (detailed description of sampling locations and methods are provided in S1 Appendix)."

Behaviour Description Quotes

"No overt reaction by conspecifics to rainbow trout sounds were observed."

Sound Name Quotes

"Table 2. Most common sounds.' 'The results of this study, and the qualitative comparisons of previously reported FRT sounds, reveal a diverse array to the form of FRT-like sounds. In general, FRTs consist of an initial broadband burst pulse where ticks are too close to resolve, followed by a train of ticks with a decaying tick interval and tick bandwidth. However, the initial broadband burst is not always present, and the tick train can be either very fast and short in duration (e.g., the VFRT), or long (as much as 10 s or more). It is also likely that some of the burst pulse sounds we have observed are FRTs that lack the tick train."

"All six species observed during this study occasionally produced FRT sounds similar to herring, however, other types of air movement sounds were far more prevalent (including the VFRT). "

"We use the term “air movement” sound to include a diverse array of sounds sometimes referred to as “air passage” or “pneumatic” sounds that arise from a variety of mechanisms involving internal air movement, and sometimes external air release, in physostomous fishes (e.g., [6–9])."