Ferguson
Sophie R.
Ferguson
Sophie R.
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ArticleGround-truthing daily and lunar patterns of coral reef fish call rates on a US Virgin Island reef(Inter Research, 2022-07-28) Ferguson, Sophie R. ; Jensen, Frants H. ; Hyer, Matthew D. ; Noble, Allison ; Apprill, Amy ; Mooney, T. AranCoral reefs comprise some of the most biodiverse habitats on the planet. These ecosystems face a range of stressors, making quantifying community assemblages and potential changes vital to effective management. To understand short- and long-term changes in biodiversity and detect early warning signals of decline, new methods for quantifying biodiversity at scale are necessary. Acoustic monitoring techniques have proven useful in observing species activities and biodiversity on coral reefs through aggregate approaches (i.e. energy as a proxy). However, few studies have ground-truthed these acoustic analyses with human-based observations. In this study, we sought to expand these passive acoustic methods by investigating biological sounds and fish call rates on a healthy reef, providing a unique set of human-confirmed, labeled acoustic observations. We analyzed acoustic data from Tektite Reef, St. John, US Virgin Islands, over a 2 mo period. A subset of acoustic files was manually inspected to identify recurring biotic sounds and quantify reef activity throughout the day. We found a high variety of acoustic signals in this soundscape. General patterns of call rates across time conformed to expectations, with dusk and dawn showing important and significantly elevated peaks in soniferous fish activity. The data reflected high variability in call rates across days and lunar phases. Call rates did not correspond to sound pressure levels, suggesting that certain call types may drive crepuscular trends in sound levels while lower-level critical calls, likely key for estimating biodiversity and behavior, may be missed by gross sound level analyses.
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ArticleRamicrusta invasive alga causes mortality in Caribbean coral larvae(Frontiers Media, 2023-04-18) Cayemitte, Kayla ; Aoki, Nadège ; Ferguson, Sophie R. ; Mooney, T. Aran ; Apprill, AmyThe settlement of coral larvae is an important process which contributes to the success and longevity of coral reefs. Coral larvae often recruit to benthic structures covered with crustose coralline algae (CCA) which produce cues that promote settlement and metamorphosis. The Peysonneliaceae Ramicrusta spp. are red-brown encrusting alga that have recently become abundant on shallow Caribbean reefs, replacing CCA habitat, overgrowing corals and potentially threatening coral recruitment. In order to assess the threat of Ramicrusta to coral recruitment, we compared the survival and settlement of Porites astreoides and Favia fragum larvae to 0.5 – 2 mg ml -1 solutions of Ramicrusta sp. or CCA as well as sterile seawater (control). In all cases larval mortality was extremely high in the Ramicrusta treatments compared to the CCA and control treatments. We found 96% (± 8.9% standard deviation, SD) mortality of P. astreoides larvae when exposed to solutions of Ramicrusta and 0 - 4% (± 0 - 8.9% SD) mortality in the CCA treatments. We observed 100% F. fragum larval mortality when exposed to Ramicrusta and 5 – 10% (± 10 – 20% SD) mortality in the CCA treatments. Settlement or surface interaction of larvae in the CCA treatments was 40 - 68% (± 22 - 37% SD) for P. astreoides and 65 - 75% (± 10 - 19% SD) for F. fragum . Two P. astreoides larva that survived Ramicrusta exposure did settle/surface interact, suggesting that some larvae may be tolerant to Ramicrusta . These results suggest that Ramicrusta is a lethal threat to Caribbean coral recruitment.
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ArticlePile driving noise induces transient gait disruptions in the longfin squid (Doryteuthis pealeii)(Frontiers Media, 2022-12-15) Seth F. Cones ; Youenn Jézéquel ; Sophie Ferguson ; Nadège Aoki ; T. Aran MooneyAnthropogenic noise is now a prominent pollutant increasing in both terrestrial and marine environments. In the ocean, proliferating offshore windfarms, a key renewable energy source, are a prominent noise concern, as their pile driving construction is among the most intense anthropogenic sound sources. Yet, across taxa, there is little information of pile driving noise impacts on organismal fine-scale movement despite its key link to individual fitness. Here, we experimentally quantified the swimming behavior of an abundant squid species (Doryteuthis pealeii) of vital commercial and ecological importance in response to in situ pile driving activity on multiple temporal and spatial scales (thus exposed to differing received levels, or noise-doses). Pile driving induced energetically costly alarm-jetting behaviors in most (69%) individuals at received sound levels (in zero to peak) of 112-123 dB re 1 µm s-2, levels similar to those measured at the kilometer scale from some wind farm construction areas. No responses were found at a comparison site with lower received sound levels. Persistence of swimming pattern changes during noise-induced alarm responses, a key metric addressing energetic effects, lasted up to 14 s and were significantly shorter in duration than similar movement changes caused by natural conspecific interactions. Despite observing dramatic behavioral changes in response to initial pile driving noise, there was no evidence of gait changes over an experiment day. These results demonstrate that pile driving disrupts squid fine-scale movements, but impacts are short-lived suggesting that offshore windfarm construction may minimally impact the energetics of this ecologically key taxon. However, further work is needed to assess potential behavioral and physiological impacts at higher noise levels.
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ArticleComparison of blastema formation after injury in two cephalopod species(Caltech Library, 2023-09-19) Ramirez, Carlos Chavez ; Khoo, Miya ; Lopez G, Marco ; Ferguson, Sophie ; Walker, Sarah ; Echeverri, KarenRegeneration is the ability to functionally replace significant amounts of lost tissue or whole appendages like arms, limbs or tentacles. The amount of tissue that can be regenerated varies among species, but regeneration is found in both invertebrate and vertebrate animals. Cephalopods have been broadly reported in the literature to regenerate their arms. There are over 800 species of Cephalopod; however, regeneration has only been documented in the literature in a few species (1). Here we compare arm regeneration in two species of cephalopod, the Octopus bimaculoides and the hummingbird bobtail squid Euprymna berryi.
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ArticleShort-term habituation of the longfin squid (Doryteuthis pealeii) to pile driving sound(Oxford University Press, 2023-10-25) Jezequel, Youenn ; Jandial, Prajna ; Cones, Seth F. ; Ferguson, Sophie R. ; Aoki, Nadège ; Girdhar, Yogesh ; Mooney, T. AranOffshore windfarms are a key renewable solution to help supply global energy needs. However, implementation has its challenges, including intense pile driving sound produced during constructions, which can affect marine life at the individual level, yet impacts at the group level remain poorly studied. Here, we exposed groups of longfin squid (Doryteuthis pealeii) in cages at multiple distances from consecutive pile driving events and sought to quantify responses at both individual and group levels. Pile driving induced short-term alarm responses at sound levels (in zero-peak) of 112–123 dB re 1 µm s−2 that were similar to those measured at kilometre scale from offshore windfarm constructions. The rate of individual alarm responses quickly decreased both within and across consecutive pile driving events, a result consistent with previous laboratory studies. Despite observing dramatic behavioural changes in response to initial pile driving sound, there were no significant differences in squid shoaling areas before and during exposure, showing no disruption of squid collective behaviours. Our results demonstrate rapid habituation of squid to pile driving sound, showing minimal effects on this ecologically and commercially key taxon. However, future work is now needed to assess responses of wild squid shoals in the vicinity of offshore windfarm constructions.
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ArticleUnidentified fish sounds as indicators of coral reef health and comparison to other acoustic methods(Frontiers Media, 2024-02-29) Jarriel, Sierra D. ; Formel, Nathan ; Ferguson, Sophie R. ; Jensen, Frants H. ; Apprill, Amy ; Mooney, T. AranThe global decline of coral reefs is a major contributor to the global biodiversity crisis and requires improved monitoring at these critically important habitats. Non-invasive passive acoustic assessments may address this need, leveraging the rich variety and spatiotemporal variability of biological sounds present in coral reef environments and offering near-continuous temporal coverage. Despite this, acoustic metrics that reliably represent coral reef health are still debated, and ground-truthing of methods is limited. Here we investigated how the prevalence of low frequency biotic sounds (without species information) relates to coral reef health, providing a foundation from which one can compare assessment methods. We first quantified call rates of these low frequency sounds for three reefs exhibiting different community assemblages around St. John, U.S. Virgin Islands, by manually annotating presumed fish noises for 1 min every 30 min across 8 days for each site. Annotated days were selected at key points across lunar cycles. These call rates were then compared with traditional visual surveys, and several acoustic methods and indices commonly used in underwater soundscape research. We found that, overall, manually detected fish call rates successfully differentiated between the three reefs, capturing variation in crepuscular activity levels–a pattern consistent with previous work that highlights the importance of diel choruses. Moreover, fish vocal rates were predictors of hard coral cover, fish abundance, and fish species richness, while most acoustic indices failed to parse out fine distinctions among the three sites. Some, such as the Acoustic Complexity Index, failed to reveal any expected differences between sites or times of day, while the Bioacoustic Index could only identify the most acoustically active reef, otherwise having weak correlations to visual metrics. Of the indices tested, root-mean-squared sound pressure level and Acoustic Entropy, both calculated in the low frequency fish band (50–1,200 Hz), showed the strongest association with visual health measures. These findings present an important step toward using soundscape cues for reef health assessments. The limited generalizability of acoustic indices across different locations emphasizes the need for caution in their application. Therefore, it is crucial to improve methods utilizing fish sounds, such as automatic fish call detectors that are able to generalize well to new soundscapes.