The harmonic interval : fact or artifact in spectral analysis of pulse trains

Originally issued as Reference No. 68-13The harmonic interval indicated during spectrographic analysis of a rapid train of pulses may be used to determine the pulse repetition-rate. If the pulse rate is regular, but too rapid to be separated, the repetition-rate may or may not be represented on such analysis as a line at the repetition frequency, but will always be indicated by the separation between harmonic bands, the harmonic interval.Office of Naval Research Contracts Nonr-4029 (00) NR 260-101 and Nonr-4446(00) NR 104-810

Whale and porpoise voices : a phonograph record

Includes accompanying booklet and image of record jacketThe vocal sounds of cetaceans are a little known and even less understood feature of the complex adaptation of these animals, whose ancestors lived on the dry land, to an entirely aquatic existence. Even in the clearest surface waters, sight is limited to about a hundred feet or less in daytime, and visibility ranges are mostly negligibly short for fast-swimming animals, so that they are effectively partly or wholly blinded. Therefore sound and hearing have an especially important place in their lives. Sound is used not only in direct communication, but also to a large degree in navigation and hunting (echo-location). The excerpts presented here are samples of such sounds made by eighteen species, all obtained by eavesdropping in the open sea (except for the Inia selection, which was made in captivity). These recordings have not been speeded up or slowed down, and so are true in natural frequency and time; there has been no editing or filtering except as noted

Underwater sounds from ribbon seal, Phoca (Histriophoca) fasciata

This paper is not subject to U.S. copyright. The definitive version was published in Fishery Bulletin 75 (1977): 450-453.Intense downward frequency "sweeps" and broadband "puffing" sounds were recorded underwater in the presence of ribbon seal, Phoca (Histriophoca) fasciata Zimmerman 1783. The recordings were made in the waters off Savoonga, St. Lawrence Island, Alaska, on 16, 17, 18, and 23 May 1967.Arctic Institute of North America under contractural agreements with the Office of Naval Research

Right whale, Eubalaena glacialis, sightings in Cape Cod waters

Sightings of right whales, Eubalaena glacialis, in Massachusetts waters have been recorded by workers at Woods Hole Oceanographic In stitution since 1955. These observations do not represent a census, because emphasis was placed on studying the whales' underwater sounds and other activities. The number of yearly sightings varied from 2 to 165. Observations were made from aircraft, boats, and occasionally from shore.Prepared for the Office of Naval Research under Contract N00014-79-C-0071; NR 083-004

Characterizing acoustic features of marine animal sounds

Software tools were designed to characterize the acoustic features of marine animal sounds. These have resulted in a set of calculated measurements that summarize particular aspects of sound sequences. The specificity of these measurements was enhanced by adjusting calculations to compensate for ambient noise. The sound measures included statistics for Aggregate Bandwidth, Intensity, Duration, Amplitude Modulation, Frequency Modulation, Short-term Bandwidth, Center Frequency, and Amplitude Frequency Interaction. The efficacy of noise compensation was tested for each statistic. Then, the sound measures were tested on a subset of 200 sequences of marine animal sounds, including sequences from 20 species: six baleen whales, 13 toothed species, and one seal. The statistics were reviewed for each species and a graphical comparison of all species was generated using principal components analysis. Preliminary results confirm that such sounds can be classified by means of relatively simple statistical algorithms, and we are encouraged to continue toward a system for automatic classification of marine animal sounds.Funding was provided by NAVSEA under Contract No. N00140-90-D-1979 and a series of contracts and grants by ONR including Grant N00014-91-J-1445 with supplemental support by NOARL and ORINCON/DARPA

Marine animal sound classification

Software was developed to measure characteristics of marine animal sounds (AcouStat). These measurements proved effective for classifying sounds in several contexts: identifying species, quantifying the repertoire of a single species, and identifying individuals. The sound measures included statistics for aggregate bandwidth, intensity, duration, amplitude modulation, frequency modulation, center frequency, and interactions among these variables. Classification analysis based on these measures suggests they adequately characterize the variability of bioacoustic signals for many problems. Correct classification to species was as high as 85%, and correct classification of dolphin whistles to individual was 90%.Funding was provided by the Office of Naval Research through the Naval Undersea Warfare Center under Contract No. N-00140-90-D-1979

Numbers of calling whales in the North Pacific

Since November 1995, the U. S. Navy's Sound Surveillance System (SOSUS) and other hydrophone arrays were used to regularly sample the occurance of whale sounds in the four regions bordering the continental margins across the North Pacific. The numbers of whales heard calling varied with the season and location for each species, Blue whales (Balaenoptera musculas), fin whales (Balaenoptera physalus), and humpback whales (Megaptera novaeangliae). For blue whales, calling during the fall season averaged 5 whales per event, winter averaged 1.5 whales per event, spring averaged 1 whale, and summer averaged 1.5 whales. For fin whales the number of whales heard ("F" calls from individuals) during winter averaged 3 whales per event, spring and fall calling averaged 1.5 whales, and summer averaged 1 whale. The "J" calling events, regardless of season, were judged to be from at least 6 fin whales. Humpback singing typically was from 3 whales. These numbers demonstrated seasonal variations in calling whales for each region.Funding was provided by CNO N45 Environmental Program and US Army Corps of Engineers (DCA87-00-H-0026) with funding from the Department of Defense Legacy Resource Management Program

Documentation for the CETACEA database of marine mammal literature references

This documentation for the CETACEA database of marine mammal literature references updates and expands the original work by Watkins, Bird, Moore, and Tyack 1988 (Reference Database Marine Mammal Literature, Technical Report WHOI-88-2). The CETACEA database is a comprehensive index of literature references used to file, store, search, retrieve, and format the data on marine animals. Organization of the references is complementary to features developed by William E. Schevill for his library of older cetacea literature, having direct association of species with over 300 indexed subjects, and with observation dates, locations, etc. This documentation describes the operation of the database (360 records), including indexing, sorting, and retrieval information developed though continued use of these systems. SPECIES and SUBJECT HEADING lists with their codes have been updated. Other databases have also developed around these indexing and sorting strategies to complement the CETACEA database, including databases of animal sounds for both the recordng data and the acoustic spectral information stored in libraries of digital sound cuts.Funding was provided by the Office of Naval Research through Contract Number N00014-88-K-0273

Observations and radio tagging of Balaenoptera edeni near Puerto La Cruz, Venezuela

The 23 October to 13 November 1979 Venezuelan radio tagging and tracking experiments on whales (Balaenoptera edeni, Fig. 1) provided essential field tests of the new modifications to the WHOI radio whale tag (see list of tag reports), and the chance to try it on a new species. We found that we could approach and tag these whales from a slow (4 to 6 kt) vessel. Good radio tracking with automatic direction finding equipment was possible within 12 to 20 km, with longer ranges probable. In addition, the radio tags provided new information about the behavior of these whales.Prepared for the Office of Naval Research under Contract N00014-79-C-OO71; NR 083-004