60 research outputs found
Ecología trófica del delfín listado en aguas del Mar de Alborán y el Golfo de Cádiz
Existe muy poca información sobre la dieta del delfín listado (Stenella coeruleoalba)
en aguas del sur de España. En este estudio se analizaron los estómagos de
61 delfines varados en Andalucía en los últimos ocho años (2007-2014). Diez estómagos
estaban vacios y de los 51 individuos restantes, 35 vararon en la costa
del Mar de Alborán y 11 en el Golfo de Cádiz. Para las 5 muestras restantes no se
dispone de localidad concreta.
Los restos de las presas en los estómagos consistieron sobre todo en estructuras
duras: otolitos, cristalinos y unos pocos huesos de peces, así como mandíbulas y
cristalinos de cefalópodos. No aparecieron otro tipo de restos lo que parece indicar
que los individuos no se habían alimentado recientemente. Para caracterizar la
dieta se calcularon tres índices (calculados para cada categoría de presa): frecuencia
de aparición en los estómagos, número de individuos y peso reconstruido
y sus porcentajes respectivos.
El delfín listado parece ser una especie predominantemente piscívora (se
identificaron restos de 5682 peces frente a solamente 210 cefalópodos) que se
alimenta de especies mesopelágicas principalmente. La familia más importante
tanto en número como en frecuencia de aparición fue Myctophidae, principalmente
Ceratoscopelus maderensis y Myctophum punctatum a las que pertenecieron casi
la mitad de los peces identificados (36,4%N, 35,3%F y 12,3%N, 25,5%F,
respectivamente). También se identificó Maurolicus muelleri (Sternoptychidae
13,4%N y 17,6%F). Otras familias identificadas presentan una distribución más
costera: Sparidae (Boops boops) y Carangidae (Trachurus sp.) (4,5%N, 9,8%F y
1,2%N, 3,9%F, respectivamente).
Los cefalópodos identificados pertenecieron a 11 familias siendo la más
abundante Ommastrephidae (26,7%N y 39,2%F). Otras familias incluyen
representantes oceánicos, Brachioteuthidae (16,7%N y 21,5%F); Chiroteuthidae
(6,7%N y 9,8%F); Enoploteuthidae (4,8%N y 3,9%F), Ancistrocheridae (0.5%N y
2%F) y otros de distribución más costera, Sepiolidae (19%N y 19,6%F), Sepiidae
(5,7%N y 3,9%F) y Loliginidae (3,8%N y 5,9%F)
The first cetacean sightings network in Spain: results of a co-operation within the Spanish Cetacean Society
3 pages, 2 tables.-- Fifteenth Annual Conference of the European Cetacean Society, Rome, Italy, 6-10 May 200ln 1999, the Spanish Cetacean Society (SEC) was created in order to co-ordinate the activities of different organisations and research groups in Spain, and to provide assistance to regional and national authorities in issues related to the conservation of the marine environment. In July 1999, the Spanish Ministry for the Environment appointed to the SEC the custody of a national database of shandings and sightings of cetaceans in order to standardise the methodology used by all groups involved in these activities, and to facilitate the exchange of information among researchers. The Sightings Working Group of the SEC has been, since then, developing and updating the cetacean sightings database with the participation of most research and conservation groups working in Spain. This is the fìrst time in Spain that most groups put together their information creating a National Sightings Network and giving a fairly complete vision of cetacean distribution throughout the whole country, showing the importance of co-ordinated co-operation in the context of conservationDGCN (National Environment Agency) of the Spanish Ministry for the EnvironmentN
Plastic accumulation in the Mediterranean Sea
Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region
Marine mammals and Good Environmental Status: Science, Policy and Society; Challenges and Opportunities
The Marine Strategy Framework Directive has become the key instrument for marine conservation in European seas. We review its implementation, focusing on cetacean biodiversity, using
the examples of Spain and the Regional Seas Convention, OSPAR. The MSFD has been widely criticised for legal vagueness, lack of coordination,
uncertainty about funding, and poor governance; its
future role within EU Integrated Maritime Policy
remains unclear. Nevertheless, the first stages of the
process have run broadly to schedule: current status,
environmental objectives and indicators have been
described and the design of monitoring programmes is in progress, drawing on experience with other environmental
legislation. The MSFD is now entering its
critical phase, with lack of funding for monitoring,
limited scope for management interventions, and
uncertainty about how conservation objectives will
be reconciled with the needs of other marine and
maritime sectors, being among the main concerns.
Clarity in governance, about the roles of the EU,
Member States, Regional Seas Conventions and
stakeholders, is needed to ensure success. However,
even if (as seems likely) good environmental status
cannot be achieved by 2020, significant steps will have been taken to place environmental sustainability
centre-stage in the development of Integrated Maritime
Policy for EU seas.Postprin
Sometimes Sperm Whales (Physeter macrocephalus) Cannot Find Their Way Back to the High Seas: A Multidisciplinary Study on a Mass Stranding
BACKGROUND: Mass strandings of sperm whales (Physeter macrocephalus) remain peculiar and rather unexplained events, which rarely occur in the Mediterranean Sea. Solar cycles and related changes in the geomagnetic field, variations in water temperature and weather conditions, coast geographical features and human activities have been proposed as possible causes. In December 2009, a pod of seven male sperm whales stranded along the Adriatic coast of Southern Italy. This is the sixth instance from 1555 in this basin. METHODOLOGY/PRINCIPAL FINDINGS: Complete necropsies were performed on three whales whose bodies were in good condition, carrying out on sampled tissues histopathology, virology, bacteriology, parasitology, and screening of veins looking for gas emboli. Furthermore, samples for age determination, genetic studies, gastric content evaluation, stable isotopes and toxicology were taken from all the seven specimens. The animals were part of the same group and determined by genetic and photo-identification to be part of the Mediterranean population. Causes of death did not include biological agents, or the "gas and fat embolic syndrome", associated with direct sonar exposure. Environmental pollutant tissue concentrations were relatively high, in particular organochlorinated xenobiotics. Gastric content and morphologic tissue examinations showed a prolonged starvation, which likely caused, at its turn, the mobilization of lipophilic contaminants from the adipose tissue. Chemical compounds subsequently entered the blood circulation and may have impaired immune and nervous functions. CONCLUSIONS/SIGNIFICANCE: A multi-factorial cause underlying this sperm whales' mass stranding is proposed herein based upon the results of postmortem investigations as well as of the detailed analyses of the geographical and historical background. The seven sperm whales took the same "wrong way" into the Adriatic Sea, a potentially dangerous trap for Mediterranean sperm whales. Seismic surveys should be also regarded as potential co-factors, even if no evidence of direct impact has been detected
Effects of a morbillivirus epizootic on long-finned pilot whales Globicephala melas in Spanish Mediterranean waters
Long-finned pilot whales Globicephala
melas are a commonly encountered species in the
Mediterranean Sea. In 2006−2007, an outbreak of the
dolphin morbillivirus in the Western Mediterranean
resulted in increased mortality of this species. The
aim of this study was to determine whether survival
rates differed between clusters of Spanish Medi -
terranean pilot whales, and how the epizootic in -
fluenced these survival rates. Photo-identification
surveys were conducted between 1992 and 2009.
Association indices were used to define clusters of
individuals that associate with each other more frequently
than with others. Based on a Cormack-Jolly-
Seber survival rate model, apparent survival rate
estimates varied from 0.821 to 0.995 over 11 clusters
for the 1992−2009 period. When the effect of the morbillivirus
outbreak was modeled, 3 clusters with distinctly
lower survival rates from previous models presented
lower estimates after the outbreak (survival
rate dropped from 0.919 [95% CI: 0.854−0.956] to
0.547 [95% CI: 0.185−0.866]), suggesting a negative
influence of the epizootic or other unknown additive
factors on certain clusters. This information is critical
for the conservation of long-finned pilot whales,
since they are listed as ‘data deficient’ in the Mediterranean Sea by the IUCN and as ‘vulnerable’ in the Spanish National Catalogue of Endangered SpeciesPeer reviewe
Maternal kinship and fisheries interaction influence killer whale social structure
The primary prey of killer whales (Orcinus orca) in the Strait of Gibraltar is the bluefin tuna (Thunnus thynnus). All killer whales observed in this area hunt tuna by chasing individual fish until they become exhausted and can be overcome. However, a subset of pods also interact with a dropline tuna fishery which has developed since 1995. Here, we investigated the social structure within and among social units (pods). Our data suggested that social structure was shaped by maternal kinship, which appears to be a species-specific trait, but also by foraging behavior, which is less common at the intra-population level. At the start of the study, only one cohesive pod interacted with the fishery, which during the course of the study underwent fission into two socially differentiated pods. Social structure within these two fishery-interacting pods was more compact and homogenous with stronger associations between individuals than in the rest of the population. Three other pods were never seen interacting with the fishery, despite one of these pods being regularly sighted in the area of the fishery during the summer. Sociality can influence the spread of the novel foraging behaviors and may drive population fragmentation, which, in this example, is already a critically small community. Observations of social changes in relation to changes in foraging at the earliest stages of diversification in foraging behavior and social segregation may provide insights into the processes that ultimately result in the formation of socially isolated discrete ecotypes in killer whales.This work was funded by Loro Parque Foundation, CEPSA, Ministerio de Medio Ambiente, Fundación Biodiversidad, LIFE+ Indemares (LIFE07NAT/E/000732) and LIFE “Conservación de Cetáceos y tortugas de Murcia y Andalucía” (LIFE02NAT/E/8610), and “Plan Nacional I+D+I ECOCET” (CGL2011-25543) of the Spanish “Ministerio de Economía y Competitividad.” RdS and JG were supported by the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R+D+I (SEV-2012-0262),” and also RdS by the “Subprograma Juan de la Cierva.
Use of blubber levels of progesterone to determine pregnancy in free-ranging live cetaceans
4 páginas, 1 tabla.We tested the possibility of measuring progesterone levels in bubbler samples collected from free-ranging live bottlenose dolphins (n = 11) and long-finned pilot whales (n = 2) as a tool to evaluate the pregnancy status of individuals. Samples were collected during January 2004 and September–October 2005 in the Strait of Gibraltar and Gulf of Cadiz and used for sex-determination by genetic methods (skin samples) and for quantification of progesterone levels by enzyme immunoassay. Photo-identification tracking of females after taking the biopsy was used to observe the presence of newborns and, in this way, to determine if the female was pregnant at the time of sampling. Mean progesterone levels from pregnant bottlenose dolphins (n = 2) were around 9 times higher than those from non-pregnant females (n = 9), with no overlap between concentration ranges demonstrating that this method could constitute an effective tool for determining pregnancy in wild populations of bottlenose dolphins and other cetacean species.Our study was made possible due to the financial support received during several cetacean campaigns in the Iberian Peninsula. We thank the Foundation Loro Parque, the Foundation Biodiversidad and CEPSA.Peer reviewe
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