Fondazione Cetacea Riccione e Ospedale delle Tartarughe

Categoria: Blog

  • Immersione mortale?

    Deadly diving? Physiological and behavioural management of decompression stress in diving mammals. 
    SK Hooker, A. Fahlman, MJ Moore, N. Aguilar de Soto, Y Bernaldo de Quiros, AO Brubakk, DP Costa, AM Costidis, S. Dennison, KJ Falke, A Fernandez, M Ferrigno, JR Fitz-Clarke, MM Garner, DS Houser, PD Jepson, DR Ketten, PH Kvadsheim, PT Madsen, NW Pollock, DS Rotstein, TK Rowles, SE Simmons, W Van Bonn, PK Weathersby, MJ Weise, TM Williams, PL Tyack.
    Proceedings of the Royal Society, London – Biological Sciences
    doi: 10.1098/rspb.2011.2088
    Abstract:
    Decompression sickness (DCS, ‘the bends’) is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N2) loading during dives.  However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply ‘minimising N2 loading’ to ‘management of the N2 load’. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.
    Keywords: diving physiology, marine mammals, gas bubbles, embolism, decompression sickness.

  • Gli ospiti dell’Ospedale delle Tartarughe

    Attualmente l’ospedale delle tartarughe marine ha in degenza sette tartarughe marine: Quasimodo il veterano , da più di due anni ospite delle vasche di Riccione; Sara, Kelly, Alex, Maria e Rino, tutte arrivate negli ultimi due mesi, pescate nelle reti a strascico. Altre tre pazienti, Theta, Piemonte e Eleonora sono ancora sotto osservazione presso la clinica Modena Sud del nostro veterinario di riferimento: il dott. Giordano Nardini che è anche membro dell’associazione Benessere Animale.

  • Risposte comportamentali dei mammiferi marini ai suoni prodotti da attività antropiche

    A New Context-Based Approach to Assess Marine Mammal
    Behavioral Responses to Anthropogenic Sounds

    W.T. ELLISON, B.L. SOUTHALL, C.W. CLARK, AND A.S. FRANKEL
    Conservation Biology, Volume **, No. *, 1–8
    2011, Society for Conservation Biology
    published online: DOI: 10.1111/j.1523-1739.2011.01803.x

    The link to the full article is http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2011.01803.x/full
    The link to the abstract is http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2011.01803.x/abstract
    and the abstract text is given below:

    Abstract: Acute effects of anthropogenic sounds on marine mammals, such as from military sonars, energy
    development, and offshore construction, have received considerable international attention from scientists,
    regulators, and industry. Moreover, there has been increasing recognition and concern about the potential
    chronic effects of human activities (e.g., shipping). It has been demonstrated that increases in human activity
    and background noise can alter habitats of marine animals and potentially mask communications for species
    that rely on sound to mate, feed, avoid predators, and navigate. Without exception, regulatory agencies
    required to assess and manage the effects of noise on marine mammals have addressed only the acute effects
    of noise on hearing and behavior. Furthermore, they have relied on a single exposure metric to assess acute
    effects: the absolute sound level received by the animal. There is compelling evidence that factors other than
    received sound level, including the activity state of animals exposed to different sounds, the nature and
    novelty of a sound, and spatial relations between sound source and receiving animals (i.e., the exposure
    context) strongly affect the probability of a behavioral response. A more comprehensive assessment method
    is needed that accounts for the fact that multiple contextual factors can affect how animals respond to both
    acute and chronic noise. We propose a three-part approach. The first includes measurement and evaluation
    of context-based behavioral responses of marine mammals exposed to various sounds. The second includes
    new assessment metrics that emphasize relative sound levels (i.e., ratio of signal to background noise and
    level above hearing threshold). The third considers the effects of chronic and acute noise exposure. All three
    aspects of sound exposure (context, relative sound level, and chronic noise) mediate behavioral response, and
    we suggest they be integrated into ecosystem-level management and the spatial planning of human offshore
    activities.

  • Fedeltà delle femmine di Leone marino alle zone di alimentazione

    A.D. Lowther, R.G. Harcourt, D.J. Hamer, S.D. Goldsworthy. (2011). Creatures of habit: foraging habitat fidelity of adult female Australian sea lions. Marine Ecology Progress Series 443: 249-263
    ABSTRACT: We examined the movement characteristics and seasonality of feeding behaviour for an
    endemic Australian otariid, the Australian sea lion Neophoca cinerea. By combining tracking data
    and stable isotope analysis of serially subsampled vibrissae from 20 adult females at 7 colonies, we
    were able to characterise individual foraging specialisation across 80% of the species range. Adult
    females expressed long-term temporal consistency in both foraging site (offshore vs. inshore) and
    prey selection. When seasonality in foraging behaviour was detected (n = 7), there was no
    consistency in variation of isotope ratios between individuals or colonies. Offshore-foraging sea lions
    fed at higher trophic levels than inshore foragers. Potentially, inshore foragers could be subdivided
    into those which targeted heterogeneously distributed seagrass meadows or calcarenite reef systems
    for different payoffs. This data highlights the importance of understanding individual specialisation
    and the dangers of generalising behaviour at the colony level. Individual specialisation in foraging
    behaviour may be a mechanism that reduces intra-specific competition, but its effectiveness will be a
    function of the temporal stability of individual differences. The present study is the first to identify
    multi-season consistency of individual foraging behaviour for any otariid. Given the long-term
    stability of adult female foraging behaviour, categorising individuals using a proxy measure such as
    whisker isotopic signature appears robust, economical, and appropriate. Such data is critical to modelling
    population response to anthropogenically driven fine-scale habitat modification.

  • Aggiornamenti Shark Alliance

    Key EU shark and ray protections maintained for 2012  The Shark Alliance is pleased to report that, at their 15-16 December meeting, the EU Council of Fisheries Ministers accepted the European Commission’s science-based proposals to maintain Total Allowable Catch (TAC) limits for porbeagle and spurdog sharks at zero. This decision comes despite pressure from the fishing industry to once again allow landings from these Critically Endangered populations.  The Shark Alliance also welcomes the ministers’ agreement to continue existing prohibitions on take of several other Threatened species, such as the common skate and undulate ray.  The Council lowered catch limits for other species of skates and rays in some areas, but reductions were less precautionary than those proposed by the Commission.  The Shark Alliance has long promoted EU shark and ray fishing limits based on scientific advice and the precautionary approach, and full protection for endangered European shark and ray species. Shark Alliance member groups actively underscored these requests before their respective ministers in October 2011 during the annual European Shark Week. While generally pleased with the outcomes from the December Council meeting, the Shark Alliance regrets that their calls to extend protections for Threatened common skate, undulate ray guitarfish, and white skate to the Mediterranean have yet to be heeded.   And you can build in these links:Link to SA background on TACs: http://www.sharkalliance.org/v.asp?rootid=7053&level1=7053&level1id=7053&level2=7088&level2id=7088&level3=7090&level3id=7090&nextlevel=7090&depth=3Council Press Release http://www.consilium.europa.eu/ueDocs/cms_Data/docs/pressData/en/agricult/127031.pdf