Sound Highways of the Sea: Mapping Acoustic Corridors for Whales and Fish in Colombia’s Pacific

Maria Paula Rey Baquero – rey_m@javeriana.edu.co
Instagram: @mariapaulareyb
Pontificia Universidad Javeriana
Fundación Macuáticos Colombia
Bogotá
Colombia

Additional Authors:
Kerri D. Seger
Camilo Andrés Correa Ayram
Natalia Botero Acosta
Maria Angela Echeverry-Galvis

Project Ports, Humpbacks y Sound In Colombia – @physicolombia
Fundación Macuaticos Colombia – @macuaticos
Semillero Aquasistemas – @aquasistemaspuj

Popular version of 4aAB5 – Modeling for acoustical corridors in patchy reef habitats of the Gulf of Tribugá, Colombia
Presented at the 188th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0037990

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Sound plays a fundamental role in marine ecosystems, functioning as an invisible network of “pathways” or corridors that connect habitat patches and enable critical behaviors like migration, communication, and reproduction. In Colombia’s northern Pacific, one of the most biodiverse regions, the Gulf of Tribugá stands out for its pristine soundscape, dominated by the sounds of marine life. Designated a UNESCO Biosphere Reserve and a “Hope Spot” for conservation, this area serves as a vital nursery for humpback whales and supports local livelihoods through ecotourism and artisanal fishing. However, increasing human activities, including boat traffic and climate change, threaten these acoustic habitats, prompting researcher on how sound influences ecological connectivity—the lifeline for marine species’ movement and survival.

This study in Colombia’s Gulf of Tribugá mapped how ocean sounds connect marine life by integrating acoustic data with ecological modeling. Researchers analyzed how sound travels through the marine environment, finding that humpback whale songs (300 Hz) create natural acoustical corridors along coastal areas and rocky islands (‘riscales’). These pathways, though occasionally interrupted by depth variations, appear crucial for whale communication, navigation, and maintaining social connections during migration. In contrast, fish calls (100 Hz) showed no detectable sound corridors, suggesting fish may depend less on acoustic signals or use alternative navigation cues like wave noise when moving between habitats.

Photographs of some of the recorded fish species. Source: Author

The research underscores that acoustical connectivity is species-specific. While humpback whales may depend on sound corridors and prioritize long-distance communication, fish may prioritize short-range communication or other environmental signals. At any distance, noise pollution disrupts these systems universally: The bubbling/popping sounds created by spinning boat propellers, for instance, generate frequencies that can covers up the whale songs and fish calls and degrade habitat quality, even if fish are less affected over the same distances that whales are. Background noise shrinks and breaks up the underwater corridors that marine animals use to communicate and navigate, harming their underwater sound habitat.

Figure 1. Received sound levels when emitted by singers (a) without noise and (b) with background noise, at a grain size of 2 Φ. The left column shows conditions without background noise, and the right column shows conditions with noise. Sound intensities most likely to be heard by a humpback whale at 200 Hz are shown in green, less likely sounds in orange, and inaudible sounds in black. Source: Author

Noise pollution alters behaviors and acoustic corridors humpback whales rely on for communication and navigation in Colombia’s Pacific waters. Notably, the fish species studied showed no sound-dependent movement, suggesting their reliance on other cues. The study advocates for sound-inclusive conservation, proposing that acoustic data (more easily gathered today via satellites, field recordings, and public databases) should join traditional metrics like currents or temperature in marine management. Protecting acoustic corridors could become as vital as safeguarding breeding grounds, especially in biodiverse hubs like Tribugá.

This work marks a first step towards integrated acoustical-ecological models, offering tools to quantify noise impacts and design smarter protections. Future research could refine species-specific sound thresholds or expand to deeper oceanic areas. For now, the message is preserving marine ecosystems requires listening, not just looking. Combining efforts to lessen human noise by using mapped soundscapes to target critical corridors could help in the conservation of marine species.

Underwater Plains and Valleys: Using Sound to Map Where Marine Life Gathers

Brandyn Lucca – blucca@uw.edu
Bluesky: @brandynlucca.bsky.social‬
Instagram: @brandynmark
Applied Physics Laboratory, University of Washington, Henderson Hall (HND), 1013 NE 40th St, Seattle, Washington, 98105, United States

Joseph Warren
Instagram: @warren.bioacoustics.lab
Bluesky: @warren-lab.bsky.social
Affiliation: School of Marine and Atmospheric Sciences, Stony Brook University

Popular version of 2aAO9 – Active acoustic detection of fish and zooplankton along bathymetric features of the New York Bight
Presented at the 188th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0037522

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Imagine standing on the beach in New York City, looking beyond the harbor over the horizon where rolling waves meet an armada of ships lined up to unload their cargo. What remains hidden from view are the vast underwater plains, valleys, and canyons teeming with marine life beneath the surface. From a bird’s-eye view, this area forms the New York Bight, a stretch of ocean off the coast of New York City situated between southern New Jersey and eastern Long Island. This seascape offers prime real estate for animals ranging from copepods to whales.

Some animals often gather along the shelfbreak, where the relatively flat, shallow seafloor of the continental shelf dramatically changes to the deep sea. Others prefer life in a well-known ecological hotspot and one of the largest marine canyons in the world: the Hudson Canyon. Like many people, marine animals choose habitats based on the amenities they offer, but their preferences can evolve as they age or in response to environmental shifts. Some may leave the New York Bight entirely, while others may settle in undiscovered hotspots elsewhere. But how can scientists find these hotspots in the first place?

How do scientists “see” beneath the waves?
Researchers use a technique called “active acoustics” to get snapshots of where animals are in the water column across large areas that can complement other sampling methods like nets. With this approach, they send out short pulses of sound from a moving ship and measure the echoes that bounce back from the seafloor or are created from animals that live in the water column. The equipment scientists use to measure these echoes is similar to bottom-finders and fish-finding systems used by fishers and boaters. The results can reveal dense fish schools clustered along the steep walls of a canyon or zooplankton aggregations in the near-surface waters along the shelfbreak. These patterns help scientists better understand how seascapes shape habitat preferences among marine organisms (Figure 1).

Echograms are one way to visualize acoustic backscatter, with color scale units corresponding to the total energy in echoes measured from marine organisms. This echogram reveals how animals are distributed vertically in the water column along a ship transect that crossed the Hudson Canyon. The dark gray region corresponds to the seafloor.

To carry out this research, scientists measure echoes from animals in the water column, collect fish and zooplankton using nets and trawls, and measure how temperature and salinity (and other environmental factors like oxygen) vary in the ocean as you go down in depth. Researchers collected the data for this study during seasonal surveys aboard a research vessel that covered the waters south of Long Island, New York, out to the shelfbreak, approximately 140 miles away (Figure 2).

Acoustic surveys were conducted along seven transect lines (black lines) with biological and seawater sampling stations at each square point. The white lines represent isobaths, or lines of constant depth, at 25, 50, 100, 500, 100, and 2000 m. The orange and red stars indicate where the Hudson Shelf Valley and Hudson Canyon begin.

Location, location, location: Hotspots change with the seasons
The New York Bight regions with the most fish and zooplankton (as measured by our echosounders) change with the seasons. In winter and early spring, most organisms concentrated farther offshore, often along the canyon edges or beyond the shelfbreak. As summer arrives, these biological hotspots grow along the shelfbreak, especially in and around the canyons, and move closer to shore. By fall, acoustic measurements showed that fish and zooplankton spread more evenly across the continental shelf.

For fish living near the seafloor, a seasonal feature called the Mid-Atlantic Cold Pool plays a major role in their movements. This layer of cold water forms on and above the seafloor over part of the continental shelf each spring and slowly decreases in volume throughout the summer. When the Cold Pool forms, many near-bottom fish shift away from their spatial extent due to the fish having temperature preferences and gather in the Hudson Canyon, other shelfbreak canyons, inshore areas, and the Hudson Shelf Valley. As the Cold Pool shrinks in late summer, their distribution becomes more like the broader patterns observed for overall biological backscatter (Figure 3).

An example echogram of biological backscatter near the shelfbreak. The 9º (gray) and 10º (black) isotherms, or lines of constant temperature, approximate the lateral and vertical extent of the Mid-Atlantic Cold Pool that, in this case, nearly walled this aggregation off from the inshore waters on the continental shelf entirely.

From underwater sound to action: Guiding management decisions
The New York Bight is a dynamic and productive ecosystem that experiences significant fishing pressure, shipping activity, and offshore energy development. By combining acoustic surveys with biological net sampling and oceanographic measurements, scientists can identify areas that fish and zooplankton may prefer (or avoid) throughout the year. Surveys such as this one help guide management decisions that balance the economic and commercial health of the New York Bight.

2pAB – Sound production of the critically endangered totoaba: applying underwater sound detection to fish species conservation

Goldie Phillips – gphillips@sci-brid.com
Sci-Brid International Consulting, LLC
16192 Coastal Hwy
Lewes, DE 19958

Gerald D’Spain – gdspain@ucsd.edu
Catalina López-Sagástegui – catalina@ucr.edu
Octavio Aburto-Oropeza – maburto@ucsd.edu
Dennis Rimington – drimington@ucsd.edu
Dave Price – dvprice@ucsd.edu
Scripps Institution of Oceanography,
University of California, San Diego
9500 Gilman Drive
San Diego, CA 92093

Miguel Angel Cisneros-Mata – macisne@yahoo.com
Daniel Guevara – danyguevara47@hotmail.com
Instituto Nacional de Pesca y Acuacultura (INAPESCA) Mexico
Del Carmen, Coyoacán
04100 Mexico City, CDMX, Mexico

Popular version of paper 2pAB
Presented Tuesday afternoon, December 3rd, 2019
178th ASA Meeting, San Diego, CA

The totoaba (Figure 1), the largest fish of the croaker family, faces a severe illegal fishing threat due largely to the high value of its swim bladder (or buche; Figure 2) in Asian markets. While several conservation measures have been implemented in the Gulf of California (GoC) to protect this endemic species, the totoaba’s current population status remains unknown. Passive acoustic monitoring (PAM) – the use of underwater microphones (called hydrophones) to detect, monitor, and localize sounds produced by soniferous species – offers a powerful means of addressing this problem.

Croaker fishes are well known for their ability to produce sound. Their characteristic “croaking” sound is produced by the vibration of their swim bladder membrane caused by the rapid contraction and expansion of nearby sonic muscles. As sound propagates very efficiently underwater, croaks and other sounds produced by species like the totoaba can be readily detected and recorded by specialized PAM systems.

However, as little is known about the characteristics of totoaba sounds, it is necessary to first gain an understanding of the acoustic behavior of this species before PAM can be applied to the GoC totoaba population. Here we present the first step in a multinational effort to implement such a system.

Totoaba

Figure 1. Totoaba housed at CREMES

Totoaba

Figure 2. Totoaba swim bladder.

We conducted a passive acoustic experiment at the aquaculture center, El Centro Reproductor de Especies Marinas (CREMES), located in Kino Bay, Mexico, between April 29 and May 4, 2019. We collected video and acoustic recordings from totoaba of multiple age classes, both in isolation and within group settings. These recordings were collectively used to characterize the sounds of the totoaba.

We found that in addition to croaks (Video 1) captive totoaba produce 4 other call types, ranging from short duration (<0.03s), low-frequency (<1kHz) narrowband pulses, classified here as “knocks” (Video 2), to longer duration, broadband clicks with significant energy over 10kHz. There is also indication that one of the remaining call types may function as an alarm or distress call. Furthermore, call rates and dominant call type were found to be dependent on age.

Video 1. Visual representation (spectrogram) of a croak produced by totoaba at CREMES. Time (in minutes and seconds) is shown on the x-axis with frequency (in kHz) displayed on the y-axis. Sounds with the greatest amplitude are indicated by warmer colors.

Video 2. Visual representation (spectrogram) of a series of “knocks” produced by totoaba at CREMES.

As PAM systems typically produce large amounts of data that can make manual detections by a human analyst extremely time-consuming, we also used several of the totoaba call types to develop and evaluate multiple automated pre-processing/detector algorithms for a future PAM system in the GoC. Collectively, results are intended to form the basis of a totoaba population assessment that spans multiple spatial and temporal scales.

1pAB4 – Combining underwater photography and passive acoustics to monitor fish

Camille Pagniello – cpagniel@ucsd.edu
Gerald D’Spain – gdspain@ucsd.edu
Jules Jaffe – jjaffe@ucsd.edu
Ed Parnell – eparnell@ucsd.edu

Scripps Institution of Oceanography, University of California San Diego
La Jolla, CA 92093-0205, USA

Jack Butler – Jack.Butler@myfwc.com
2796 Overseas Hwy, Suite 119
Marathon, FL 33050

Ana Širović – asirovic@tamug.edu
Texas A&M University Galveston
P.O. Box 1675
Galveston, TX 77550

Popular version of paper 1pAB4 “Searching for the FishOASIS: Using passive acoustics and optical imaging to identify a chorusing species of fish”
Presented Monday afternoon, November 5, 2018
176th ASA Meeting, Victoria, Canada

Although over 120 marine protected areas (MPAs) have been established along the coast of southern California, it has been difficult to monitor their ability to quantify their effectiveness via the presence of target animals. Traditional monitoring methods, such as diver surveys, allow species to be identified, but are laborious and expensive, and heavily rely on good weather and a talented pool of scientific divers. Additionally, the diver’s presence is known to alter animal presence and behavior. As one alternative to aid and perhaps, in the long run, replace the divers, we explored the use of long-term, continuous, passive acoustic recorders to listen to the animals’ vocalizations.

Many marine animals produce sound. In shallow coastal waters, fish are often a dominant contributor. Aristotle was the first to note the “voice” of fish, yet only sporadic reports on fish sounds appeared over the next few millennia. Many of the over 30,000 species of fish that exist today are believed to produce sound; however, the acoustic behavior has been determined in less than 5% of these biologically and commercially important animals.

Towards the goal of both listening to the fish and identifying which species are vocalizing, we developed a Fish Optical and Acoustic Sensor Identification System (FishOASIS) (Figure 1). This portable, low-cost instrument couple’s a multi-element passive acoustic array with multiple cameras, thus allowing us to determine which fish are making which sound for a variety of species. In addition to detecting sporadic events such as fish spawning aggregations, this instrument also provides the ability to track individual fish within aggregations.

FishOASIS

Figure 1. A diver deploying FishOASIS in the kelp forest off La Jolla, CA.

Choruses (i.e., the simultaneous vocalization of animals) are often associated with fish spawning aggregations and, in our work, FishOASIS was successful in recording a low-frequency fish chorus in the kelp forest off La Jolla, CA (Figure 2).

Figure 2. Long-term spectral average (LTSA) of low-frequency fish chorus of unknown species on June 8, 2017 at 17:30:00. Color represents spectrum level, with red indicating highest pressure level.

The chorus starts half an hour before sunset and lasts about 3-4 hours almost every day from May to September. While individuals within the aggregation are dispersed over a large area (approx. 0.07 km2), the chorus’ spatial extent is fairly fixed over time. Species that could be producing this chorus include kelp bass (Paralabrax clathratus) and halfmoons (Medialuna californiensis) (Figure 3).

Figure 3. A halfmoon (Medialuna californiensis) in the kelp forest off La Jolla, CA.

FishOASIS has also been used to identify the sounds of barred sand bass (Paralabrax nebulifer), a popular species among recreational fishermen in the Southern California Bight (Figure 4).

Figure 4. Barred sand bass (Paralabrax nebulifer) call.

This article demonstrates that combining multiple cameras with multi-element passive acoustic arrays is a cost-effective method for monitoring sound-producing fish activities, diversity and biomass. This approach is minimally invasive and offers greater spatial and temporal coverage at significantly lower cost than traditional methods. As such, FishOASIS is a promising tool to collect the information required for the implementation of passive acoustics to monitor MPAs.