Deep-diving odontocetes
foraging strategies and their prey field
as determined by acoustic techniques

Giacomo Giorli

Postdoctoral Researcher, Hawaii Institute of Marine Biology

University of Hawaii

THURSDAY, February 23, 2017
Pacific Forum—11:00 a.m.

Deep-diving odontocetes (sperm, short-finned pilot, and beaked whales; and Risso’s dolphins) are known to forage at deep depths in the ocean on squid and fish. These marine mammal species are top predators, and for this reason they are very important for the ecosystems they live in; they can affect prey populations and control food web dynamics through top-down effects. Many human marine activities are causing impacts on wild populations of deep-diving odontocetes by emitting noise in their natural environment (i.e., military exercises at sea, shipping, pile driving operations, etc.) that may cause animals to strand ashore. A better understanding of their distribution, foraging habits, and deep-sea habitats they feed in is the key to reducing these impacts through the regulation of noise emissions in areas that represent a good habitat for these species.

The studies I will present in this seminar investigate the foraging strategies of this group of marine mammals and the density and size of their potential prey in the deep ocean using passive and active acoustic techniques. Passive acoustics recorders were used to monitor the foraging activity of deep-diving odontocetes, and the density and size of animals living in deep-sea scattering layers was studied using a DIDSON imaging sonar at multiple stations along the Kona coast of Hawaii. Sperm and beaked whale foraging was found to vary in time and space, as well as the density of potential prey. Future studies should aim at linking the variability of these odontocetes foraging with the variability of prey in the deep ocean.

Print Version (PDF)

Next: March 1, Tom Weber


Data repository
Data policy
What is happening in Monterey Bay today?
Central and Northern California Ocean Observing System
Chemical data
Ocean float data
Slough data
Mooring ISUS measurements
Southern Ocean Data
Mooring data
M1 Mooring Summary Data
M1 Asimet
M1 Download Info
M1 EMeter
M1 Fluorometer (CeNCOOS)
Molecular and genomics data
ESP Web Portal
Seafloor mapping
Upper ocean data
Spatial Temporal Oceanographic Query System (STOQS) Data
Image gallery
Video library
Previous seminars
David Packard Distinguished Lecturers
Research software
Video Annotation and Reference System
System Overview
Annotation Interface
Video Tape User Guide
Video File User Guide
Annotation Glossary
Query Interface
Basic User Guide
Advanced User Guide
Query Glossary
VARS Publications
Oceanographic Decision Support System
MB-System seafloor mapping software
How to Download and Install MB-System
MB-System Documentation
MB-System Announcements
MB-System Announcements (Archive)
MB-System FAQ
MB-System Discussion Lists
MB-System YouTube Tutorials
Matlab scripts: Linear regressions
Introduction to Model I and Model II linear regressions
A brief history of Model II regression analysis
Index of downloadable files
Summary of modifications
Regression rules of thumb
Results for Model I and Model II regressions
Graphs of the Model I and Model II regressions
Which regression: Model I or Model II?
Matlab scripts: Oceanographic calculations
Matlab scripts: Sound velocity
Visual Basic for Excel: Oceanographic calculations
Educational resources
MBARI Summer Internship Program
2017 Summer Interns Blog
Education and Research: Testing Hypotheses (EARTH)
EARTH workshops
2016—New Brunswick, NJ
2015—Newport, Oregon
2016 Satellite workshop—Pensacola, FL
2016 Satellite workshop—Beaufort, NC
EARTH resources
EARTH lesson plans
Lesson plans—published
Lesson plans—development
Lesson drafts—2015
Lesson drafts—2016 Pensacola
Adopt-A-Float Program
Center for Microbial Oceanography: Research and Education (C-MORE) Science Kits
Sample archive