Temporal and spatial mapping of red grouper Epinephelus morio sound production

Abstract

The goals of this project were to determine the daily, seasonal and spatial patterns of red grouper Epinephelus morio sound production on the West Florida Shelf (WFS) using passive acoustics. An 11 month time series of acoustic data from fixed recorders deployed at a known E. morio aggregation site showed that E. morio produce sounds throughout the day and during all months of the year. Increased calling (number of files containing E. morio sound) was correlated to sunrise and sunset, and peaked in late summer (July and August) and early winter (November and December). Due to the ubiquitous production of sound, large-scale spatial mapping across the WFS of E. morio sound production was feasible using recordings from shorter duration-fixed location recorders and autonomous underwater vehicles (AUVs). Epinephelus morio were primarily recorded in waters 15-93 m deep, with increased sound production detected in hard bottom areas and within the Steamboat Lumps Marine Protected Area (Steamboat Lumps). AUV tracks through Steamboat Lumps, an offshore marine reserve where E. morio hole excavations have been previously mapped, showed that hydrophone-integrated AUVs could accurately map the location of soniferous fish over spatial scales of <1 km. The results show that passive acoustics is an effective, non-invasive tool to map the distribution of this species over large spatial scales.

Fish Spawning Aggregations Dynamics as Inferred From a Novel, Persistent Presence Robotic Approach

“…Their deployments can last over 1 month and their range can expand over 100 km, with periodic surfacing for data offload and GPS positioning. In recent years AUGs have been used in ocean soundscape mapping (Matsumoto et al, 2011;Bingham et al, 2012;Wall et al, 2012;Baumgartner et al, 2013) and more recently in fisheries independent surveys (Wall et al, 2014(Wall et al, , 2017 on the shelf of the continental U.S. AUGs surveys are less contingent upon large amount of funding being available for ship and personnel time and therefore have the potential to provide long time series at a relatively lower cost. Data collected through passive acoustic surveys are used to assess the presence of soniferous fish with the ultimate goal of assessing biomass and supporting stock assessment activities, while studying the ecological importance of many important commercial species in the U.S.…”

“…CAS are consistent with reproductive behaviors and can provide an estimation of relative reproductive behavior activity and relative abundance through the spawning period (Rowell et al, 2012). Therefore, PAMs can be used to locate spawning aggregations (Luczkovich et al, 1999(Luczkovich et al, , 2008Walters et al, 2009;Rowell et al, 2011) and determine temporal patterns in reproductive behavior and habitat use by different species during FSAs (Locascio and Mann, 2008;Mann et al, 2009Mann et al, , 2010Nelson et al, 2011;Schärer et al, 2012a,b). The species-specific sounds produced by grouper during reproductive behaviors are somewhat stereotyped and can be audibly and visually (in spectrograms) distinguished from each other due to unique duration, peak frequency, call structure and tonal characteristics ( Table 1).…”

“…Passive acoustic monitoring (PAM) is a fisheries-independent approach that can provide in situ observations of soniferous fishes, such as groupers (Mann et al, 2010;Rowell et al, 2011Rowell et al, , 2015Schärer et al, 2012aSchärer et al, ,b, 2014Wall et al, 2014Wall et al, , 2017. Additionally, PAM can be relatively non-intrusive and provides data on timing and duration of grouper activity and distribution.…”

“…For example, the use of autonomous platforms such as buoyancydriven gliders or wave-gliders that are equipped with PAM systems can be programed more accurately to encompass FSA spatial extents as well as scout regions of the shelf edge in the exploration of unknown FSAs. Wall et al (2014) used a Slocum glider, a buoyancy driven autonomous underwater glider (AUG), to conduct a large-scale spatial mapping across the West Florida shelf of red grouper (E. Morio) sound production. A similar survey was conducted with the same technology along the southeast U.S. (Wall et al, 2017).…”

Long-term acoustic monitoring of fish calling provides baseline estimates of reproductive timelines in the May River estuary, southeastern USA

“…However, there are not many studies where signal detectors have been created to detect fish acoustic signals, especially successful ones that can identify fish calling amidst a noisy background. Recently, automatic call recognition was applied to identify Lusitanian toadfish Halobatrachus didactylus vocalizations in Portugal and red grouper Epinephelus morio calls on the West Florida Shelf, but these soundscapes are quieter than estuaries and the diversity of soniferous fishes was less than in the May River (Wall et al 2014, Vieira at al. 2015.…”