2 research outputs found
Spatial and temporal distribution of cetaceans in the mid-Atlantic waters around the Azores
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Taylor & Francis for personal use, not for redistribution. The definitive version was published in Marine Biology Research 10 (2014): 123-137, doi:10.1080/17451000.2013.793814.Cetaceans living in offshore waters are under increasing pressure from anthropogenic
activities. Yet, due to the lack of survey effort, relatively little is known about the
demography or ecology of these populations. Spatial and temporal distribution of
cetaceans in mid-Atlantic waters were investigated using a long term dataset collected
from boat surveys and land-based observations around the Azores. From 1999 to
2009, 7307 cetacean schools were sighted during 271717 km of survey effort. In 4944
h of land-based observations, 2968 cetacean groups were detected. Twenty-four
species were recorded: seven baleen whales, six beaked whales, eight dolphin species,
Physeter macrocephalus, Kogia breviceps and K. sima. Overall, Delphinus delphis
was the most frequently sighted species but its encounter rate decreased in June-
November, coinciding with presence of Stenella frontalis in the region. Tursiops
truncatus, P. macrocephalus and Grampus griseus were frequently encountered yearround,
whereas large baleen whales showed a distinct peak in encounter rates in
March-May. Mesoplodonts were fairly common and appear to be present throughout
the year. These findings fill-in a significant gap in the knowledge of cetaceans
occurring in a poorly studied region of the North Atlantic, providing much needed
data to inform management initiatives.This work
was supported by FEDER funds, through the Competitiveness Factors Operational
Programme – COMPETE, by national funds, through FCT – Foundation for Science
and Technology, under projects CETAMARH (POCTI/BSE/38991/01) and TRACE
(PTDC/MAR/74071/2006), and by regional funds, through DRCT/SRCTE, under
project MAPCET (M2.1.2/F/012/2011). We thank the Azorean Regional Government
for funding POPA, the Shipowners Proprietors and the Association of the Tuna
Canning Industries for their support to the programme. MAS was supported by an
FCT postdoctoral grant (SFRH/BPD/29841/2006), and IC and RP were supported by
doctoral grants SFRH/BD/41192/2007 and SFRH/BD/32520/2006. IMAR-DOP/UAç
is the R&D Unit #531 and part of the Associated Laboratory #9 (ISR) funded through
the pluri-annual and programmatic funding schemes of FCT-MCTES and DRCTAzores
Macro- and micro-geographic variation of short-beaked common dolphin’s whistles in the Mediterranean Sea and Atlantic Ocean
Author Posting. © The Author(s), 20113. This is the author's version of the work. It is posted here by permission of Taylor & Francis for personal use, not for redistribution. The definitive version was published in Ethology Ecology & Evolution 26 (2014): 392-404, doi:10.1080/03949370.2013.851122.Genetic studies have shown that there are small but significant differences
between the short-beaked common dolphin populations in the Atlantic Ocean and
those in the Mediterranean Sea. The short-beaked common dolphin is a highly vocal
species with a wide sound production repertoire including whistles. Whistles are
continuous, narrowband, frequency-modulated signals that can show geographic
variation in dolphin species. This study tests whether the differences, highlighted by
genetic studies, are recognisable in the acoustic features of short-beaked common
dolphin’s whistles in the two adjacent areas of the Atlantic Ocean and the
Mediterranean Sea. From a selected sample of good quality whistles (514 recorded
in the Atlantic and 193 in the Mediterranean) 10 parameters of duration, frequency
and frequency modulation were measured. Comparing data among basins, differences
were found for duration and all frequency parameters except for minimum
frequency. Modulation parameters showed the highest coefficient of variation.
Through discriminant analysis we correctly assigned 75.7% of sounds to their basins.
Furthermore, micro-geographic analysis revealed similarity between the sounds
recorded around the Azores and the Canary archipelagos and between the Bay of
Biscay and the Mediterranean Sea. Results are in agreement with the hypothesis
proposed by previous genetic studies that two distinct populations are present, still supposing a gene flow between the basins. This study is the first to compare shortbeaked
common dolphin’s whistles of the Atlantic Ocean and the Mediterranean
areas.Data collection and processing in the Azores was conducted
under projects POCTI/BSE/38991/01, PTDC/MAR/74071/2006 and M2.1.2/F/012/2011, supported by
FCT (Fundação para a Ciência e a Tecnologia) and DRCTC/SRCTE (Secretaria Regional de
Ciência, Tecnologia e Equipamentos), FEDER funds, the Competitiveness Factors Operational
(COMPETE), QREN European Social Fund and Proconvergencia Açores Program. We acknowledge
funds provided by FCT to LARSyS Associated Laboratory & IMAR-University of the Azores/
the Thematic Area E of the Strategic Project (OE & Compete) and by the DRCTC – Government of
the Azores pluriannual funding. M.A. Silva was supported by an FCT postdoctoral grant (SFRH/
BPD/29841/2006). I. Cascão and R. Prieto were supported by FCT doctoral grants (SFRH/BD/
41192/2007 and SFRH/BD/32520/2006, respectively) and R. Prieto by a research grant from the Azores Regional Fund for Science and Technology (M3.1.5/F/115/2012). Data collection by SECAC
(Society for the Study of Cetaceans in the Canary Archipelago) was funded by the U.E. LIFE
programme – project LIFE INDEMARES (LIFE 07/NAT/E/000732)- and the Fundación
Biodiversidad, under the Spanish Ministry of Environment, Rural and Marine Affairs (project
ZEC-TURSIOPS).2014-11-0