Tipi di suoni Misticeti

Transcript

1 Bioacustica 1. prodotti 2. Funzione dei suoni 3. Passive Acoustic per gli studi di popolazione 4. Identificazione acustica degli odontoceti del Mediterraneo

2 Misticeti There is no standard nomenclature for baleen whale sounds. Similar sounds are oftn given different names by differents authors. ( ). It is difficult to study context and functions of baleen whale sounds. Unlike others marine mammals, baleen whale are rarely held in captivity. It has rarely been possible to associate specific whale sounds with specific animals activities where under observation. (Marine mammals and noise, 1995)

3 Odontoceti Odontocete sounds can be classified into three general categories: tonal whistle, pulsed sounds (echolocation), and less distincte pulsed sounds such as cries, grunts, and barks. (Marine mammals and noise, 1995) Whistle: maggior parte dell energia <20 KHz. Grande variabilità (single wh, loop, multi) Clicks e pulsed sounds: 1-90 al secondo, KHz (P. macrocephalus: KHz)

4 Odontoceti - Dd

5 Odontoceti

6 Odontoceti - Dd

7 Odontoceti - Dd

8 Odontoceti - Gm

9 Odontoceti - Gm

10 Odontoceti - Sc

11 Odontoceti - Sc

12 Odontoceti - Pc

13 Odontoceti - Pc

14 Odontoceti - Pc

15 Odontoceti - Pc

16

17 Funzione dei suoni The vocalizations of dolphins are assumed to have communication, navigation, and food location functions. Some researchers have advanced a "signature whistle" hypothesis, that states that certain vocalizations that are emitted by preference by individuals in a pod represent an acoustic "signature" for that individual.

18 Stock assessment e habitat use con metodi acustici NOOA workshop, la Jolla (CA), novembre 2002 Survey acustici attuali: incremento della capacità di avvistamento visivo. Survey acustici futuri: analisi della struttura di popolazione determinare relazione tra la struttura di popolazione determinata con l acustica e quella determinata con la genetica analisi di abbondanza e densità necessarie ulteriori ricerche per l identificazione acustica delle specie, soprattutto dei piccoli cetacei (già utilizzato per capodoglio e alcuni misticeti) disturbo da rumore naturale densità relativa, distribuzione stagionale, trends.

19 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS

20 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS

21 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS

22 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS Sperm whales are deep diving animals. They regularly make dives to depths of around 1000m lasting over 45 minutes. For this reason, traditional survey methods, which involve searching for them by eye, are less effective than acoustic surveys. Fortunately for us, while they are submerged, sperm whales make loud clicks, which can be heard several miles away. By listening to the clicks it is possible to track its movement underwater without even setting eyes on it.

23 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS Counting acoustically has the following other advantages over traditional survey methods: Acoustic surveys can continue 24 hours a day, therefore using boat time more efficiently. Acoustic surveys can be automated, as we have done for sperm whales, making them more objective and less prone to variations in the efficiency of individual observers.

24 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS Automatic acoustic surveys do not require a large observer team, so they can be carried out from smaller vessels and platforms of opportunity. Acoustic surveys are less affected by changes in sea state than visual surveys, again making them more efficient.

25 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS

26 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS

27 Sperm Whale Survey in the Mediterranean Sea IFAW ACCOBAMS

28 Necessarie ulteriori ricerche per l identificazione acustica degli altri odontoceti, per il loro monitoraggio acustico passivo Sound propagate long distances in the ocean (Medwin and Clay 1998) and many cetaceans are extremely vocal (Richardson et al. 1995). Steiner (1981) correctly classified the whistle of five western North Atlantic odontocete species 70% of the time. Wang et al. (1995) correctly classified the whistle 65% of seven odontocete species from diverse geographic locations. Rendell et al. (1999) correctly classified 55% of the whistle of five odontocete species form diverse geographic locations. Oswald et al. (2003) correctly classified the whistle 41,5% of nine odontocete species in the ETP. Correct classification scores obtained in most whistle classification studies have been significantly greater than would be expected by chance alone, suggesting that differences in whistle structures can be used to identify species. Mancavano studi per il Mediterraneo

29 Oswald et al. 2003: acoustic identification of nine delphinid species in the ETP