New information on the diet of True's beaked whale (<i>Mesoplodon mirus</i>, Gray 1850), with insights into foraging ecology on mesopelagic prey

Hernández-Milian, Gema; Lusher, Amy; OBrian, J; Fernandez, A.; O’Connor, Ian; Berrow, Simon; Rogan, Emer

doi:10.1111/mms.12430

Cited by 7 publications

(5 citation statements)

References 21 publications

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“…Each beaked whale species in these studies was found to produce echolocation clicks containing a frequency-modulated (FM) upsweep; these echolocation clicks, as well as buzzes, were produced during deep dives (>400 m), which suggest that beaked whales forage during these dives (e.g., Johnson et al, 2004). Stomach content analyses of dead specimens, showing diets of meso-and bathypelagic fish and squid (MacLeod et al, 2003;MacLeod et al, 2006b;Wenzel et al, 2013;Hernandez-Milian et al, 2017), also suggest deep-water foraging. In addition to the use of animal-borne sensors, shipboard surveys that combine visual observations and passive acoustic data collection using single or arrayed hydrophones have facilitated the acoustic characterization of the echolocation clicks of multiple species (e.g., Hooker and Whitehead, 2002;Gillespie et al, 2009;Rankin et al, 2011;Cholewiak et al, 2013).…”

Section: Introductionmentioning

confidence: 79%

A description of echolocation clicks recorded in the presence of True's beaked whale (Mesoplodon mirus)

DeAngelis

Stanistreet

Baumann‐Pickering

et al. 2018

The Journal of the Acoustical Society of America

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True's beaked whales (Mesoplodon mirus) were encountered on two separate shipboard surveys on 24 July 2016 and 16 September 2017 in the western North Atlantic Ocean. Recordings were made using a hydrophone array towed 300 m behind the ship. In 2016, three different groups were sighted within 1500 m of the ship; clicks were recorded for 26 min. In 2017, a single group of five whales was tracked over the course of five hours in which the ship maintained a distance <4000 m from the group. A total of 2938 frequency-modulated (FM) clicks and 7 buzzes were recorded from both encounters. Plausible inter-click-intervals (ICIs) were calculated from 2763 clicks, and frequency and duration measurements were calculated from 2150 good quality FM clicks. The median peak frequencies were 43.1 kHz (2016, n = 718) and 43.5 kHz (2017, n = 1432). Median ICIs were 0.17 s (2016) and 0.19 s (2017). The spectra and measurements of the recorded clicks closely resemble Gervais's beaked whale clicks (Mesoplodon europaeus) and distinguishing between the two species in acoustic data sets proves difficult. The acoustic behavior of True's beaked whales was previously unknown; this study provides a description of echolocation clicks produced by this species.

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Section: Introductionmentioning

confidence: 79%

A description of echolocation clicks recorded in the presence of True's beaked whale (Mesoplodon mirus)

DeAngelis

Stanistreet

Baumann‐Pickering

et al. 2018

The Journal of the Acoustical Society of America

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“…Members of the Ziphiidae family comprise approximately 30% of the world's cetacean species, and although knowledge of their ecology has seen a substantial increase during the last two decades, many species remain little studied (Hernandez-Milian et al 2017). Observations that document their occurrence and natural behaviour are therefore of significant value.…”

Section: Discussionmentioning

confidence: 99%

“…Like other Ziphiids, the Shepherd's beaked whale is believed to use echolocation when foraging at depth (Johnson et al 2004;Leunissen et al 2018) and to feed predominantly on squid and fish (Hernandez-Milian et al 2017). Existing dietary information supports this theory, but is limited to an examination of stomach contents of a single stranded female in Tristan da Cunha, which revealed 13 cephalopod and 8 fish species from beaks and otoliths respectively (Best et al 2014).…”

Section: Discussionmentioning

confidence: 99%

First underwater sighting of Shepherd’s beaked whale (Tasmacetus shepherdi)

2019

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Here we describe the first underwater sighting of Shepherd's beaked whale (Tasmacetus shepherdi). Two individuals were observed together on video footage obtained via mid-water stereo-Baited Remote Underwater Video Systems (BRUVS) deployed off the coast of Inaccessible Island, Tristan da Cunha, in the South Atlantic. This observation constitutes the first recorded live sighting of this species in the waters of Tristan da Cunha since 2002 and provides further evidence for the persistence of a population of this species in the region. The observed individuals lacked the dark flipper stripe observed in previous descriptions, indicating that the species may exhibit greater variation in pigmentation than previous records indicate. The planned implementation of a marine reserve in the region along with the current low level of fishing pressure and remote location of this archipelago provide a good context to ensure the appropriate management and protection of this rare species. The recent establishment of an ongoing mid-water stereo-BRUVS monitoring programme, in concert with other methods targeted at marine mammals, may yield further information about this little known species and aid in informing management decisions in the future.

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“…In particular, the tuna and three out of the four marine mammal species that were detected were all from Cast 9. All of these predator species are known to feed on mesopelagic fishes to some extent, as well as cephalopods and crustaceans (Santos et al, 2001;Benoit-Bird and Au, 2003;Mostarda et al, 2007;Hernandez-Milian et al, 2017). While these eDNA signatures originated from different depths, the concentration of signals from this cast suggests that this particular cast location was a foraging hotspot.…”

Section: Predator Detection and Inferring Trophic Relationshipsmentioning

confidence: 99%

Assessing mesopelagic fish diversity and diel vertical migration with environmental DNA

Govindarajan,

Llopiz,

Caiger

et al. 2023

Front. Mar. Sci.

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Mesopelagic fishes are an important component of the world’s oceans in terms of their abundance, biomass, and ecosystem function. These fishes are important contributors to the biological carbon pump via their feeding and behaviors, whereby they facilitate the transfer of carbon from shallow waters to the deep sea. Several species undertake diel vertical migration, feeding in shallower waters at night and moving to deeper waters during the day. This process actively expedites the downward flux of carbon. However, carbon budgets and climate models require accurate information regarding the depth distributions and migration patterns of these fishes, and environmental DNA (eDNA) analyses can provide this information. Here, we utilize eDNA approaches, generating taxonomically-informative COI and 12S reference barcodes for 80 species of mesopelagic fishes, which can be used for species-level identification of eDNA sequences. Using these, along with a publicly available barcodes database, we compare results from eDNA analysis with traditional net sampling, and explore the ability of eDNA techniques to detect diel vertical migration in fishes from samples collected in Northwest Atlantic Slope Water. We found that eDNA and net samples often resulted in different species identifications, demonstrating that eDNA can detect species that would otherwise be missed with traditional methods. In our eDNA samples, we also detected more species (12) in our shallowest depth category (0 - 100 m) from night samples than from day samples (3). This is consistent with increased diversity in shallow waters at night due to diel vertical migration. Based on the variability observed in sample duplicates, we suggest that future mesopelagic eDNA studies incorporate larger sample volumes and scaled-up sampling efforts. We also note the potential applications of eDNA analysis in addressing ecological questions related to predator-prey relationships identification of foraging hotspots, and carbon flow through the ocean’s midwaters.

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New information on the diet of True's beaked whale (Mesoplodon mirus, Gray 1850), with insights into foraging ecology on mesopelagic prey

Cited by 7 publications

References 21 publications

A description of echolocation clicks recorded in the presence of True's beaked whale (Mesoplodon mirus)

A description of echolocation clicks recorded in the presence of True's beaked whale (Mesoplodon mirus)

First underwater sighting of Shepherd’s beaked whale (Tasmacetus shepherdi)

Assessing mesopelagic fish diversity and diel vertical migration with environmental DNA

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