DOCSLIB.ORG

Abundance and Habitat Preferences of the Short-Beaked Common Dolphin Delphinus Delphis in the Southwestern Mediterranean: Implications for Conservation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Abundance and Habitat Preferences of the Short-Beaked Common Dolphin Delphinus Delphis in the Southwestern Mediterranean: Implications for Conservation Vol. 4: 309–331, 2008 ENDANGERED SPECIES RESEARCH Printed June 2008 doi: 10.3354/esr00073 Endang Species Res Published online May 27, 2008 OPENPEN ACCESSCCESS Abundance and habitat preferences of the short-beaked common dolphin Delphinus delphis in the southwestern Mediterranean: implications for conservation A. Cañadas1,*, P. S. Hammond2 1ALNITAK & SEC, Nalón 16, 28240 Hoyo de Manzanares, Madrid, Spain 2Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife KY16 8LB, UK ABSTRACT: The Mediterranean sub-population of short-beaked common dolphin is believed to have suffered a steep decline in the Mediterranean in recent years, and in 2003 it was listed as endangered in the IUCN Red List of Threatened Species. Effective conservation will depend critically on our understanding of the relationship between the species and its habitats. The Alborán Sea is believed to be the most important remaining Mediterranean habitat for this species, and thus consti- tutes a vital source of information for the development of conservation measures. We used spatial modelling to estimate the abundance and explore the habitat use of common dolphins in this area, examining regional, seasonal and interannual variations, as well as the influence of biological factors such as presence of calves, interspecific relationships and behaviour. From 1992 to 2004, 37 385 km of non-systematic line transects generated 738 sightings in a 19 189 km2 study area. The point esti- mate of abundance was 19 428 (95% CI = 15 277 to 22 804) dolphins. Seasonal and geographical vari- ations in abundance were detected, with higher average density in summer than in winter, and in the Western Alborán Sea than in the east Gulf of Vera, which has different physical/environmental char- acteristics. No overall trend in abundance was observed in the Alborán area. However, a decline was observed in the Gulf of Vera, with a summer density 3-fold lower in the period from 1996 to 2004 than in 1992 to 1995. A potential link of this decline with prey depletion due to the exponential growth of aquaculture in the area is discussed. Clear differences in habitat use were also found when examin- ing the influence of biological factors. In particular, groups with calves and groups that were feeding preferred more coastal waters. This result could have important implications for the development of conservation measures for this species in the Mediterranean. KEY WORDS: Common dolphin · Mediterranean · Generalized Additive Models · GAMs · Abundance · Trends · Habitat use · Alborán Sea Resale or republication not permitted without written consent of the publisher INTRODUCTION the IUCN, was listed as endangered in the Interna- tional Union for the Conservation of Nature and Nat- Short-beaked common dolphins Delphinus delphis ural Resources, World Conservation Union (IUCN) Red (hereafter referred to as ‘common dolphins’) in the List of Threatened Species, based on criterion A2, Mediterranean appear to have suffered a steep decline which refers to a 50% decline in abundance over the over recent decades (UNEP/IUCN 1994, Aguilar et al. last 3 generations (35 to 45 yr), the causes of which 1995, Bearzi et al. 2003), although no reliable time ‘may not have ceased or may not be understood or series of abundance data exist. In 2003, the Mediter- may not be reversible’ (www.iucnredlist.org/search/ ranean common dolphin subpopulation, as defined by details.php/41762/summ). Possible causes of this de- *Email: [email protected] © Inter-Research 2008 · www.int-res.com 310 Endang Species Res 4: 309–331, 2008 cline include: by-catch, depletion of food resources (Bearzi et al. 2004). Genetic studies of Mediterranean due to overfishing, toxic pollution or a combination of common dolphins found that animals in the Alborán these factors (Bearzi et al. 2003). Sea are genetically more closely related to those in The IUCN/Species Survival Commission (SSC) the northeast Atlantic than to those in the eastern Cetacean Specialist Group has recommended that Mediterranean and may constitute a different popula- studies to ‘investigate the distribution, abundance, tion from the latter (Natoli 2005). This structuring of population structure, and factors threatening the con- the population may have important implications for servation of short-beaked common dolphins in the conservation. Mediterranean and Black Seas’ be intensified (Reeves The only large-scale cetacean survey in the western et al. 2003). ACCOBAMS (the Agreement for the Con- part of the Mediterranean Sea was carried out in 1991 servation of Cetaceans in the Black Sea, Mediter- to 1992 (Forcada & Hammond 1998). The latter study ranean Sea and contiguous Atlantic Area under the estimated abundance of common dolphins in the UN Convention for Migratory Species) commissioned Alborán Sea as follows: 14 736 common dolphins (95% the development of a Conservation Plan for the com- CI = 6923 to 31 366; coefficient of variation [CV] = 0.40) mon dolphin in the Mediterranean Sea (Bearzi et al. in an area of 90 670 km2. The only other estimate of 2004). In its Implementation Priorities (ACCOBAMS abundance in the Mediterranean is for a small inshore 2002) proposed that areas containing critical habitat area in the Ionian Sea, based on photo-identification of for priority species should be identified, in which pilot around 100 animals (Bearzi et al. 2003). conservation and management projects should be Previous studies in the northeastern Alborán Sea developed and implemented immediately. In the Con- examined the influence of depth and slope on the dis- servation Plan, areas considered to be of special tribution of common dolphins (Cañadas et al. 2002) but conservation value for common dolphins (Areas of without any attempt to predict distribution based on Conservation Importance, ACIs), and therefore poten- the described relationships. In the present study we tial marine protected areas (MPAs) were selected analyse a much more extensive dataset on this species based on the — admittedly limited — knowledge of the in the whole northern Alborán Sea to model regional, distribution and frequency of occurrence of common seasonal and inter-annual variation in abundance and dolphins in the Mediterranean. habitat preferences, and to map model predictions to This knowledge — as well as information on the inform spatial aspects of conservation and manage- scale and relative importance of actual or potential ment. To estimate abundance we use model-based anthropogenic threats to dolphins and priorities of pos- line-transect sampling methods (Hedley et al. 1999, sible mitigation measures — is lacking, but must be Marques 2001), recently applied to common bottlenose increased quickly if effective conservation actions are dolphins Tursiops truncatus in this area (Cañadas & to be implemented (Bearzi et al. 2004). Most impor- Hammond 2006). tantly, baseline population abundance and information Distribution and habitat use of a species with com- on distribution is needed to put any identified threats plex ecology, social structure and behaviour are very to common dolphins into context and to establish prior- likely influenced not only by ‘extrinsic’ (i.e. abiotic and ity conservation and mitigation measures. Monitoring biotic environmental) factors but also by ‘intrinsic’ distribution and abundance is necessary to determine factors (e.g. reproductive status, feeding strategies, whether these measures are fulfilling established behaviour, inter-specific relationships). Understanding conservation objectives. these influences and the inter-relationships among In general, MPAs or marine reserves may offer a them will greatly improve our understanding and solution to some of the challenges involved in manage- interpretation of the species’ ecology as well as ment of the marine environment. They allow conserva- improving our ability to develop targeted and more tion efforts or management actions to focus at a geo- effective mitigation and conservation measures. In the graphical scale that is more tangible for the general present paper, we begin to explore the habitat prefer- public. In this way, marine reserves can allow the ences of common dolphins in the study area, examin- organisation of human activities through zoning (e.g. ing ‘intrinsic’ factors such as presence of calves, inter- ‘no take’ zones and buffer zones), at the same time as specific relationships and behaviour, thereby building preserving the natural attributes of the region and its on the work of Cañadas et al. (2002, 2005). This is the value as a tool for public awareness and education. first time these methods have been used in such an One of the ACIs selected in the ACCOBAMS Con- investigation of a cetacean species. servation Plan for common dolphins in the Mediter- We discuss the implications of the results for the con- ranean Sea is the Alborán Sea (see Fig. 1), largely servation of common dolphins in the Mediterranean because the encounter rates for this species in this Sea, especially with respect to bycatch in fishing nets area are the highest in the whole Mediterranean basin and the establishment of MPAs. Cañadas & Hammond: Abundance and habitat preferences of Delphinus delphis 311 MATERIALS AND METHODS surveyed the region of Murcia (northern Gulf of Vera). From 1992 to 1998 surveys were made during March Data collection. Survey area, survey design and and April and from June to September. The study area searching effort: Surveys were conducted during the was sampled in January,
Load more

Recommended publications
  • Resolution 3.11 Conservation Plan for Black Sea Cetaceans
    ACCOBAMS-MOP3/2007/Res.3.11 RESOLUTION 3.11 CONSERVATION PLAN FOR BLACK SEA CETACEANS The Meeting of the Parties to the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic area: On the recommendation of the ACCOBAMS Scientific Committee, Aware that all three Black Sea cetacean species, the harbour porpoise (Phocoena phocoena), the short-beaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Turpsiops truncatus), experienced a dramatic decline in abundance during the twentieth century, Taking into account that the International Union for the Conservation of Nature (IUCN)-ACCOBAMS workshop on the Red List Assessment of Cetaceans in the ACCOBAMS Area (Monaco, March 2006) concluded that the Black Sea populations of the harbour porpoise, common dolphin and bottlenose dolphin are endangered, Conscious that most of the factors responsible for their decline, such as current fisheries by-catches, extensive habitat degradation and other anthropogenic impacts, pose continuous threats to the existence of cetaceans in the Black Sea and contiguous waters, represented by the Sea of Azov, the Kerch strait and the Turkish straits system (including the Bosphorus strait, the Marmara Sea and the Dardanelles straits), Convinced that the plan is an integral component of discussions on Black Sea regional and national strategies, plans, programmes and projects concerned with the protection, exploration and management of the Black Sea environment, biodiversity, living resources, marine mammals
    [Show full text]
  • Is Harbor Porpoise (Phocoena Phocoena) Exhaled Breath Sampling Suitable for Hormonal Assessments?
    animals Article Is Harbor Porpoise (Phocoena phocoena) Exhaled Breath Sampling Suitable for Hormonal Assessments? Anja Reckendorf 1,2 , Marion Schmicke 3 , Paulien Bunskoek 4, Kirstin Anderson Hansen 1,5, Mette Thybo 5, Christina Strube 2 and Ursula Siebert 1,* 1 Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Werftstrasse 6, 25761 Buesum, Germany; [email protected] (A.R.); [email protected] (K.A.H.) 2 Centre for Infection Medicine, Institute for Parasitology, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany; [email protected] 3 Clinic for Cattle, Working Group Endocrinology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany; [email protected] 4 Dolfinarium, Zuiderzeeboulevard 22, 3841 WB Harderwijk, The Netherlands; paulien.bunskoek@dolfinarium.nl 5 Fjord & Bælt, Margrethes Pl. 1, 5300 Kerteminde, Denmark; [email protected] * Correspondence: [email protected]; Tel.: +49-511-856-8158 Simple Summary: The progress of animal welfare in wildlife conservation and research calls for more non-invasive sampling techniques. In cetaceans, exhaled breath condensate (blow)—a mixture of cells, mucus and fluids expelled through the force of a whale’s exhale—is a unique sampling matrix for hormones, bacteria and genetic material, among others. Especially the detection of steroid hormones, such as cortisol, is being investigated as stress indicators in several species. As the only Citation: Reckendorf, A.; Schmicke, native cetacean in Germany, harbor porpoises (Phocoena phocoena) are of special conservation concern M.; Bunskoek, P.; Anderson Hansen, and research interest. So far, strandings and live captures have been the only method to obtain K.; Thybo, M.; Strube, C.; Siebert, U.
    [Show full text]
  • Identifying Sexually Mature, Male Short-Beaked Common Dolphins (Delphinus Delphis) at Sea, Based on the Presence of a Postanal Hump
    Aquatic Mammals 2002, 28.2, 181–187 Identifying sexually mature, male short-beaked common dolphins (Delphinus delphis) at sea, based on the presence of a postanal hump Dirk R. Neumann1, Kirsty Russell2, Mark B. Orams1, C. Scott Baker2, and Padraig Duignan3 1Coastal Marine Research Group, Massey University, Auckland, New Zealand 2Department of Biology, University of Auckland, New Zealand 3Department of Veterinary Science, Massey University, Palmerston North, New Zealand Abstract Introduction For detailed studies on the behaviour and social To fully comprehend the behaviour and social organization of a species, it is important to organization of a species, it is necessary to distinguish males and females. Many delphinid distinguish males and females. Long-term studies species show little sexual dimorphism. However, in of bottlenose dolphins (Tursiops truncatus, T. mature male spinner dolphins, Stenella longirostris aduncus), which tracked focal individuals of known (Perrin & Gilpatrick, 1994) and Fraser’s dolphins, sex, revealed sexual segregation of mature males Lagenodelphis hosei (Jefferson et al., 1997), tissue from females (Wells, 1991), the formation of male between the anus and the flukes forms a so-called coalitions (Wells, 1991; Connor et al., 1992), and peduncle keel, or postanal hump. We discovered an differences in the activity budgets of males and analogous feature in free-ranging short-beaked females (Waples et al., 1998). Many delphinid common dolphins, Delphinus delphis,offthe species show little sexual dimorphism, which makes north-eastern coast of New Zealand’s North Island. it exceedingly difficult to sex individuals at sea. For Genetic analysis of skin samples obtained from many species, the only individuals that can be sexed bow-riding individuals revealed that dolphins without capture are those that are consistently with a postanal hump were indeed always male.
    [Show full text]
  • Anomalously Pigmented Common Dolphins (Delphinus Sp.) Off Northern New Zealand Karen A
    Aquatic Mammals 2005, 31(1), 43-51, DOI 10.1578/AM.31.1.2005.43 Anomalously Pigmented Common Dolphins (Delphinus sp.) off Northern New Zealand Karen A. Stockin1 and Ingrid N. Visser2 1Coastal-Marine Research Group, Institute of Natural Resources, Massey University, Private Bag 102 904, North Shore MSC, Auckland, New Zealand 2Orca Research Trust, P.O. Box 1233, Whangarei, New Zealand Abstract New Zealand waters is provided by Bernal et al. (2003) who suggested that common dolphins exhib- Anomalous pigmentations have been recorded in iting long rostra, as photographed in New Zealand many cetacean species. However, typically only by Doak (1989; Plates 34A, 34B), are long-beaked one variation is reported from a population at common dolphins. However, as Amaha (1994) and a time (e.g., an albino). Here we record a spec- Jefferson & Van Waerebeek (2002) highlighted, trum of pigmentation from common dolphins neither New Zealand nor Australian common dol- (Delphinus sp.) off northern New Zealand. All- phins neatly fit the morphological description of black, dark-morph, pale-morph, and all-white either D. delphis or D. capensis. In the past, New individuals, as well as variations between these Zealand common dolphins have been identified have been recorded. Pale-coloured pectoral flip- from pigmentation patterns in the field and classi- pers are prevalent, and a number of individuals fied as short-beaked common dolphins (Bräger & with white “helmets” have been observed. Schneider, 1998; Gaskin, 1968; Neumann, 2001; Webb, 1973), although pigmentation alone may not Key Words: common dolphin, Delphinus delphis, be sufficient to positively identity these dolphins to Delphinus capensis, anomalous pigmentation, species.
    [Show full text]
  • List of Marine Mammal Species and Subspecies Written by The
    List of Marine Mammal Species and Subspecies Written by the Committee on Taxonomy The Ad-Hoc Committee on Taxonomy , chaired by Bill Perrin, has produced the first official SMM list of marine mammal species and subspecies. Consensus on some issues was not possible; this is reflected in the footnotes. This list will be revisited and possibly revised every few months reflecting the continuing flux in marine mammal taxonomy. This list can be cited as follows: “Committee on Taxonomy. 2009. List of marine mammal species and subspecies. Society for Marine Mammalogy, www.marinemammalscience.org, consulted on [date].” This list includes living and recently extinct species and subspecies. It is meant to reflect prevailing usage and recent revisions published in the peer-reviewed literature. Author(s) and year of description of the species follow the Latin species name; when these are enclosed in parentheses, the species was originally described in a different genus. Classification and scientific names follow Rice (1998), with adjustments reflecting more recent literature. Common names are arbitrary and change with time and place; one or two currently frequently used in English and/or a range language are given here. Additional English common names and common names in French, Spanish, Russian and other languages are available at www.marinespecies.org/cetacea/ . The cetaceans genetically and morphologically fall firmly within the artiodactyl clade (Geisler and Uhen, 2005), and therefore we include them in the order Cetartiodactyla, with Cetacea, Mysticeti and Odontoceti as unranked taxa (recognizing that the classification within Cetartiodactyla remains partially unresolved -- e.g., see Spaulding et al ., 2009) 1.
    [Show full text]
  • Understanding Harbour Porpoise (Phocoena Phocoena) and Fisheries Interactions in the North-West Iberian Peninsula
    20th ASCOBANS Advisory Committee Meeting AC20/Doc.6.1.b (S) Warsaw, Poland, 27-29 August 2013 Dist. 11 July 2013 Agenda Item 6.1 Project Funding through ASCOBANS Progress of Supported Projects Document 6.1.b Project Report: Understanding harbour porpoise (Phocoena phocoena) and fisheries interactions in the north-west Iberian Peninsula Action Requested Take note Submitted by Secretariat / University of Aberdeen NOTE: DELEGATES ARE KINDLY REMINDED TO BRING THEIR OWN COPIES OF DOCUMENTS TO THE MEETING Final report to ASCOBANS (SSFA/ASCOBANS/2010/4) Understanding harbour porpoise (Phocoena phocoena) and fishery interactions in the north-west Iberian Peninsula Fiona L. Read1,2, M. Begoña Santos2,3, Ángel F. González1, Alfredo López4, Marisa Ferreira5, José Vingada5,6 and Graham J. Pierce2,3,6 1) Instituto de Investigaciones Marinas (C.S.I.C), Eduardo Cabello 6, 36208 Vigo, Spain 2) School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Aberdeen, United Kingdom 3) Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, PO Box 1552, 36200, Vigo, Spain 4) CEMMA, Apdo. 15, 36380, Gondomar, Spain 5) CBMA/SPVS, Departamento de Biologia, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal 6) CESAM, Departamento de Biologia, Universidade do Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal Coordinated by: In collaboration with: 1 Final report to ASCOBANS (SSFA/ASCOBANS/2010/4) Introduction The North West Iberian Peninsula (NWIP), as defined for the present project, consists of Galicia (north-west Spain), and north-central Portugal as far south as Peniche (Figure 1). Due to seasonal upwelling (Fraga, 1981), the NWIP sustains high productivity and high biodiversity, including almost 300 species of fish (Solørzano et al., 1988) and over 75 species of cephalopods (Guerra, 1992).
    [Show full text]
  • COMMON DOLPHIN Delphinus Delphis (Short-Beaked) & Delphinus Capensis (Long-Beaked)
    AMERICAN CETACEAN SOCIETY FACT SHEET P.O. Box 1391 - San Pedro, CA 90733-1391 - (310) 548-6279 COMMON DOLPHIN Delphinus delphis (short-beaked) & Delphinus capensis (long-beaked) CLASS: Mammalia ORDER: Cetacea SUBORDER: Odontoceti FAMILY: Delphinidae GENUS: Delphinus SPECIES: delphis (short-beaked) & capensis (long-beaked) The common dolphin throughout history has often been recorded in art and literature. It was recently proposed that two forms of this species, the short- and long-beaked common dolphin, represent two distinct species. PHYSICAL DESCRIPTION Common dolphins are colorful, with a complex crisscross or hourglass color pattern on the side; the long-beaked common dolphin being more muted in color. When looking at the profile of the two common dolphin species, the short-beaked common dolphin has a more rounded melon that meets the beak at a sharp angle, as compared to the long-beaked common dolphin that has a flatter melon that meets the beak at a more gradual angle. COLOR Color patterns on the common dolphin are the most elaborate of any cetacean. The back is dark gray-to-black from the top of the head to the tail dipping to a V on the sides below the dorsal fin. The flanks are light gray behind the dorsal fin and yellowish-tan forward of the dorsal fin, forming an hourglass pattern. Its belly is white. There are large dark circles around the eyes connected by a dark line that runs across the head behind the beak and a black stripe runs from the jaw to the flippers. FINS AND FLUKES The dorsal fin is triangular-to-falcate (curved).
    [Show full text]
  • Eat and Be Eaten Porpoise Diet Studies
    EAT AND BE EATEN PORPOISE DIET STUDIES Maarten Frederik Leopold Thesis committee Promotor Prof. dr. ir. P.J.H. Reijnders Professor of Ecology and Management of Marine Mammals Wageningen University Other members Prof. dr. A.D. Rijnsdorp, Wageningen University Prof. dr. U. Siebert, University of Veterinary Medicine, Hannover, Germany Prof. dr. M. Naguib, Wageningen University Mr M.L. Tasker, Joint Nature Conservation Committee, Peterborough, United Kingdom This research was conducted under the auspices of the Netherlands Research School for the Socio-Economic and Natural Sciences of the Environment (SENSE). EAT AND BE EATEN PORPOISE DIET STUDIES Maarten Frederik Leopold Thesis submitted in fulfilment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus Prof. dr. ir. A.P.J. Mol, in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Friday 20 November 2015 at 4 p.m. in the Aula. Maarten Frederik Leopold Eat or be eaten: porpoise diet studies 239 pages PhD thesis, Wageningen University, Wageningen, NL (2015) With references, with summaries in Dutch and English ISBN 978-94-6257-558-5 There is a crack a crack in everything... that’s how the light gets in Leonard Cohen (1992) Anthem Contents 1. Introduction: Being small, living on the edge 9 2. Not all harbour porpoises are equal: which factors determine 26 what individual animals should, and can eat? 3. Are starving harbour porpoises (Phocoena phocoena) sentenced 56 to eat junk food? 4. Stomach contents analysis as an aid to identify bycatch 88 in stranded harbour porpoises Phocoena phocoena 5.
    [Show full text]
  • Habitat Modelling of Harbour Porpoise (Phocoena Phocoena) in the Northern Gulf of St
    Living among giants: Habitat modelling of Harbour porpoise (Phocoena phocoena) in the Northern Gulf of St. Lawrence By Raquel Soley Calvet Masters Research in Marine Mammal Science Supervision by: Dr. Sonja Heinrich Dr. Debbie J. Russell Sea Mammal Research Unit, August 2011 Table of contents Abstract .................................................................................................................................i 1. Introduction 1.1 Cetacean habitat modelling....................................................................................1 1.2 Ocean Models........................................................................................................2 1.3 The Gulf of St. Lawrence......................................................................................3 1.4 Biology of Harbour Porpoises...............................................................................4 1.5 Aims.......................................................................................................................6 2. Materials and Methods 2.1 Study Area..............................................................................................................7 2.2 Data collection........................................................................................................8 2.3 Generating pseudo-absences.................................................................................10 2.4 Analysis.................................................................................................................11
    [Show full text]
  • Omslag 2011-7.Indd 1 25/08/2011 12:05 Authors
    Conservation plan for the Harbour Porpoise Phocoena phocoena in The Netherlands: towards a favourable conservation status Kees (C.J.) Camphuysen & Marije L. Siemensma NIOZ Royal Netherlands Institute for Sea Research omslag 2011-7.indd 1 25/08/2011 12:05 Authors C.J. (Kees) Camphuysen Royal Netherlands Institute for Sea Research P.O. Box 59, 1790 AB Den Burg, Texel, NL Tel. + 31 222 369488, E-mail: [email protected] M.L. (Marije) Siemensma Marine Science & Communication Bosstraat 123, 3971 XC Driebergen-Rijssenburg, NL Tel. + 31 6 16830430 E-mail: [email protected] Commissioning This project was commissioned and nanced by the Dutch Ministry of Economics, Agriculture and Innovation Cover illustration Reproduced with permission from The J. Paul Getty Museum, Los Angeles. Jan van de Cappelle (1649) “Shipping in a Calm at Flushing with a States General Yacht Firing a Salute” Oil on oak panel, Unframed: 69.5 x 92.1 cm. The im- age shows numerous animals in the water that could be recognised as Harbour Porpoises, which were abundant at the time. Recommended citation Camphuysen C.J. & M.L. Siemensma (2011). Conservation plan for the Harbour Porpoise Phocoena phocoena in The Netherlands: towards a favourable conservation status. NIOZ Report 2011-07, Royal Netherlands Institute for Sea Re- search, Texel. © 2011 Royal Netherlands Institute for Sea Research omslag 2011-7.indd 4 25/08/2011 12:06 Conservation plan for the Harbour Porpoise Phocoena phocoena in The Netherlands: towards a favourable conservation status Kees (C.J.) Camphuysen & Marije L. Siemensma © 2011 Royal Netherlands Institute for Sea Research 1 Conservation plan Harbour Porpoise in The Netherlands – NIOZ Report 2011-07 Authors C.J.
    [Show full text]
  • The Possible Reasons for Bottlenose Dolphins (Tursiops Truncatus) Participating In
    The possible reasons for bottlenose dolphins (Tursiops truncatus) participating in non-predatory aggressive interactions with harbour porpoises (Phocoena phocoena) in Cardigan Bay, Wales Leonora Neale Student ID: 4103778 BSc Zoology Supervised by Dr Francis Gilbert Word count: 5335 Contents Page Page: ABSTRACT……………………………………………………………………….......1 INTRODUCTION…………………………………………………..............................3 METHODS………………………………………………………………....................9 Study species………………………………………………………………......9 Study area………………………………………………………………….…10 Methods of data collection………………………………………...................10 Methods of data analysis………………………………………......................13 RESULTS………………………………………………………………………........14 Geographical distribution……………………………………………….......14 Object-oriented play……………………………………………………........15 DISCUSSION………………………………………………………………….…….18 Geographical distribution……………………………………………………18 Object-oriented play…………………………………………………….........18 Diet………………………………………………………………...................21 CONCLUSION………………………………………………………………………23 ACKNOWLEDGEMENTS………………………………………………………….25 REFERENCES………………………………………………………………………26 APPENDIX……………………………………………………………………..........33 CBMWC sightings………………………...………………………………….…33 CBMWC sightings form guide………………...………………………….….34 CBMWC excel spreadsheet equations……………………………………......35 Abstract Between 1991 and 2011, 137 harbour porpoises (Phocoena phocoena) died as a result of attacks by bottlenose dolphins (Tursiops truncatus) in Cardigan Bay. The suggested reasons for these non-predatory aggressive interactions
    [Show full text]
  • Relative Prey Size Consumption in Toothed Whales: Implications for Prey Selection and Level of Specialisation
    MARINE ECOLOGY PROGRESS SERIES Vol. 326: 295–307, 2006 Published November 17 Mar Ecol Prog Ser Relative prey size consumption in toothed whales: implications for prey selection and level of specialisation C. D. MacLeod1,*, M. B. Santos1, 2, A. López3, G. J. Pierce1 1School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK 2Instituto Español de Oceanografia, Centro Costro de Vigo, Cabo Estay, Canido, 36208 Vigo, Spain 3Coordinadora para o Estudio dos Mamiferos Mariños (CEMMA), Apdo. 15, 36380 Gondomar, Pontevedra, Spain ABSTRACT: We investigated whether toothed whales consume prey in relation to their availability in the local environment based on the fact that availability of potential prey is likely to decrease expo- nentially with increasing size, reflecting the usual size–abundance relationships found in marine communities. We calculated relative prey size frequency spectra for 13 species of toothed whale from the northeast Atlantic. These differed considerably from an exponential distribution, suggesting that toothed whales preferentially consume larger, less abundant organisms over smaller, more abundant ones. The prey size spectra of the various cetacean species could be separated into 3 distinct groups based on the strength of the mode, maximum value and inter-quartile range. Group 1 species, such as the common dolphin, consume a wide range of relatively large organisms. In contrast, Group 2 and 3 species, such as the northern bottlenose whale and the sperm whale respectively, specialise on nar- row ranges of relatively small organisms. We hypothesise that these differences are related to the mode of prey capture. Group 1 species can capture prey using pincer-like movement of jaws contain- ing a large number of small, homodont teeth, as well as suction-feeding, allowing them to be rela- tively generalist in terms of relative prey size.
    [Show full text]