Combining whistle acoustic parameters to discriminate Mediterranean odontocetes during passive acoustic monitoring.
Acoustic observation can complement visual observation to more effectively monitor occurrence and distribution of marine mammals. For effective acoustic censuses, calibration methods must be determined by joint visual and acoustic studies. Research is still needed in the field of acoustic species identification, particularly for smaller odontocetes. From 1994 to 2012, whistles of four odontocete species were recorded in different areas of the Mediterranean Sea to determine how reliably these vocalizations can be classified to species. Recordings were attributed to species by simultaneous visual observation. The results of this study highlight that the frequency parameters, which are linked to physical features of animals, show lower variability than modulation parameters, which are likely to be more dependent on complex eco-ethological contexts. For all the studied species, minimum and maximum frequencies were linearly correlated with body size. DFA and Classification Tree Analysis (CART) show that these parameters were the most important for classifying species; however, both statistical methods highlighted the need for combining them with the number of contour minima and contour maxima for correct classification. Generally, DFA and CART results reflected both phylogenetic distance (especially for common and striped dolphins) and the size of the species.
Life Sciences and Systems Biology Department, University of Torino, Via Accademia Albertina 13, 10123 Torino, Italy.
Marta
M
Azzolin
Groupe de Recherche sur les Cétacés (GREC), BP 715, 06633 Antibes, France.
Alexandre
A
Gannier
Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, Hawaii 96744.
Marc O
MO
Lammers
Bio-Waves, Inc., 364 2nd Street, Suite #3, Encinitas, California 92024.
Julie N
JN
Oswald
Life Sciences and Systems Biology Department, University of Torino, Via Accademia Albertina 13, 10123 Torino, Italy.
Elena
E
Papale
Bioacoustics Lab, IAMC Capo Granitola, National Research Council, Via del Mare 6, 91021 Torretta Granitola (TP), Italy.
Giuseppa
G
Buscaino
Bioacoustics Lab, IAMC Capo Granitola, National Research Council, Via del Mare 6, 91021 Torretta Granitola (TP), Italy.
Gaspare
G
Buffa
Bioacoustics Lab, IAMC Capo Granitola, National Research Council, Via del Mare 6, 91021 Torretta Granitola (TP), Italy.
Salvatore
S
Mazzola
Life Sciences and Systems Biology Department, University of Torino, Via Accademia Albertina 13, 10123 Torino, Italy.
Cristina
C
Giacoma
D000162:Acoustics; D000818:Animals; D049628:Body Size; D050681:Bottle-Nosed Dolphin / Q000145:classification / Q000502:physiology / Q000523:psychology; D050696:Common Dolphins / Q000145:classification / Q000502:physiology / Q000523:psychology; D003663:Decision Trees; D004289:Dolphins / Q000145:classification / Q000502:physiology / Q000523:psychology*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D016014:Linear Models; D008522:Mediterranean Sea; D015233:Models, Statistical; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013045:Species Specificity; D050706:Stenella / Q000145:classification / Q000502:physiology / Q000523:psychology; D014796:Visual Perception; D014828:Vocalization, Animal; D050686:Whales, Pilot / Q000145:classification / Q000502:physiology / Q000523:psychology