DOCSLIB.ORG

Synthesis of Effects of Oil on Marine Mammals

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Synthesis of Effects of Oil on Marine Mammals OCS Study MMS 88-0049 SYNTHESIS OF EFFECTS OF OIL ON MARINE MAMMALS Edited by J.R. Geraci and D.J. St. Aubin Department of Pathology Ontario Veterinary College University of Guelph NIG 2WI Canada Submitted by: Battelle Memorial Institute 1431 Spinnaker Drive Ventura, California 93001 U.S.A. Department of Interior Minerals Management Service Atlantic OCS Region Contract No. 14-12-0001 -30293 September 1988 This publication has been reviewed by the Minerals Management Service (MMS) and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the MMS, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. Table of Contents Page Chapter I Composition and Fate of Petroleum and Spill-Treating Agents in the Marine Environment Introduction .................................................... 2 Composition and Toxicity of Petroleum ........................... 2 Refined Oil Products .......................................... 6 Similar Compounds of Natural and Pyrogenic Origin ............. 6 Toxicity of Petroleum Compounds ............................... 7 Sources of Petroleum in the Marine Environment .................. 8 Fate of Petroleum in the Marine Environment ..................... 11 Spreading and Drifting ........................................ 11 Evaporation ................................................... 15 Dissolution ................................................... 18 Dispersion and Emulsion Formation ............................. 18 Photochemical Reactions ....................................... 19 Biodegradation ................................................ 19 Deposition in Sediments ....................................... 22 Interaction of Weathering Processes ........................... 23 Oil Dispersants ................................................. 23 Other Methods of Treating Spills ................................ 25 Use of Chemical Dispersants and ~leiningAgents ................. 26 Fate of Dispersants in the Marine Environment ................... 26 Overview of Possible Interactions between Petroleum and Marine Mammals ........................................ 27 Physical Contact with Oil ..................................... 27 Accumulation of Oil from Air and Water ........................ 28 Ingestion of Oil-Contaminated Food ............................ 28 Effects of Oil Dispersants ...................................... 31 Distribution of Oil Inputs and Marine Mammals ................... 31 Literature Cited ................................................ 33 Chapter 2 Pinnipeds and Oil: Ecologic Perspectives Introduction .................................................... 42 Distribution ................................................... 42 Life Histories .................................................. 46 General Patterns .............................................. 46 .. Birth and Care.of Young ....................................... 46 Growth and Maturation ......................................... 46 Diet and Feeding Tactics ...................................... 89 Page Chapter 2 cont d . Habitat Use ..................................................... 89 Major Patterns of Distribution ................................ 89 Habitat Features .............................................. 94 Movements and Migration Patterns .............................. 96 Habitat Aspects of Reproduction ............................... 97 Population Size and Habitat Quality ........................... 98 Social Organization and Behavior ................................ 98 Non-reproductive Groups ....................................... 99 Reproductive Behavior ......................................... 99 Grooming ......................................................100 Commensalism with Humans ...................................... 100 Demography ...................................................... 100 Life-history Parameters .......................................101 The Possibility of Local Extinction ........................... 101 Population Recovery After Catastrophe ........................ 106 Literature Cited ................................................ 110 Chapter 3 Physiologic and Toxicologic Effects on Pinnipeds ' Historical Notes ................................................ 121 Detection and Avoidance of Oil .................................. 130 Behavioral Effects .............................................. 131 Surface Contact - Eyes and Mucous Membranes ..................... 132 Surface Contact - Integument ....................................133 Oil Ingestion ...................................................134 Inhalation ...................................................... 136 Summary ......................................................... 137 Literature Cited ................................................138 Chapter 4 Cetaceans and Oil: Ecologic Perspectives Introduction .................................................... 144 Distribution ................................................... 144 Life Histories ..................................................152 Habitat Use .....................................................153 Habitat Features .............................................. 153 Home Range and Site Fidelity .................................. 154 Migrations .................................................... 154 Trophic Levels and Feeding Habits ............................. 155 Reproduction .................................................. 156 Social Organization and Behavior ................................ 156 Group Structure and Social Behavior ........................... 156 Page Chapter 4 cont ' d Reproductive Behavior ......................................... 157 Feeding Behavior ........................................158 Other Behaviors ............................................... 159 Summarizing the Risk ............................................ 159 Literature Cited ................................................ 160 Chapter 5 Physiologic and Toxicologic Effects on Cetaceans Historical Notes ..................................................168 Reactions of Cetaceans to Oil .................................. 169 Detection and Avoidance ......................................... 175 Surface Contact ..................................................183 Inhalation ...................................................... 185 Baleen Fouling ...................................................&85 Ingestion and Accumulation ...................................... 193 Summary ......................................................... 195 Literature Cited ................................................197 Chapter 6 Sea Otters and Oil: Ecologic Perspectives Introduction .................................................... 204 Distribution .................................................... 204 Preferred Habitat................................................ 207 Site Fidelity and Movement Patterns ............................. 207 Reproduction ....................................................208 Social Organization and Reproductive Behavior ................... 209 Trophic Levels and Feeding Habits ................................ 210 Metabolism and Thermoregulation ................................. 211 Summarizing the Risk ............................................. 212 Literature Cited ................................................ 213 Chapter 7 Physiologic and Toxicologic Effects on Sea Otters Historical Perspective .......................................... 217 Detection and Avoidance ......................................... 218 Surface Fouling ................................................. 219 Cleaning Fouled Otters ........................................ 231 Other Effects ................................................... 222 Summary ......................................................... 222 Literature Cited ................................................ 223 iii * Chapter 8 Polar Bears and Oil: Ecologic Perspectives Introduction ....................................................226 Distribution .................................................... 226 Life History .................................................... 229 Migration ..................................................... 229 Habitat Preference ............................................ 230 Exploration and Production Activities in Prime Habitats ......... 231 Habitat Modification ............................................ 232 Behavior ........................................................232 Hunting ....................................................... 232 Reproduction .................................................. 235 Investigative Behavior ........................................ 236 Summarizing the Risk ............................................ 236 Literature Cited ................................................ 237 . Chapter 9 Physiologic and Toxicologic Effects on Polar Bears Historical Notes ................................................. 240 Detection and Avoidance ..........................................i 240 Surface Contact .................................................. 241 Oil Ingestion ................................................... 243 Balancing the Effects ........................................... 243 Literature Cited ................................................245 Chapter 10 Oil Effects on Manatees:
Load more

Recommended publications
  • List of Marine Mammal Species and Subspecies
    List of Marine Mammal Species and Subspecies Introduction The Committee on Taxonomy, chaired by Patricia Rosel, produced the first official Society for Marine Mammalogy list of marine mammal species and subspecies in 2010. Consensus on some issues has not been possible; this is reflected in the footnotes. The list is updated at least annually. The current version was updated in May 2020. This list can be cited as follows: “Committee on Taxonomy. 2019. List of marine mammal species and subspecies. Society for Marine Mammalogy, www.marinemammalscience.org, consulted on [date].” This list includes living and recently extinct (within historical times) species and subspecies. It is meant to reflect prevailing usage and recent revisions published in the peer-reviewed literature. Classification and scientific names follow Rice (1998), with adjustments reflecting more recent literature. Author(s) and year of description of each taxon follow the Latin (scientific) species name; when these are enclosed in parentheses, the taxon was originally described in a different genus. The Committee annually considers and evaluates new, peer-reviewed literature that proposes taxonomic changes. The Committee’s focus is on alpha taxonomy (describing and naming taxa) and beta taxonomy primarily at lower levels of the hierarchy (subspecies, species and genera), although it may evaluate issues at higher levels if deemed necessary. Proposals for new, taxonomically distinct taxa require a formal, peer-reviewed study and should provide robust evidence that some subspecies or species criterion was met. For review of species concepts, see Reeves et al. (2004), Orr and Coyne (2004), de Queiroz (2007), Perrin (2009) and Taylor et al.
    [Show full text]
  • Endangered Species: the Marine Otter by Gale, Cengage Learning, Adapted by Newsela Staff on 04.20.18 Word Count 436 Level 400L
    Endangered Species: The marine otter By Gale, Cengage Learning, adapted by Newsela staff on 04.20.18 Word Count 436 Level 400L Image 1. Marine otters are sometimes called "sea cats." Photo from Wikimedia Commons. Have you ever seen a sea otter? You might have spotted one in the ocean or at a zoo. Sea otters are one kind of otter. The marine otter is another kind. The marine otter lives in South America. It lives along the west coast. That is where the land touches the Pacific Ocean. This otter is sometimes called a sea cat. It is about the size of a cat. It has a long body. Its head is flat. The marine otter has tiny ears and long whiskers. It has short legs and webbed feet. This makes the otter a great swimmer. The otters feed on sea animals. They like crabs and oysters. They swim on their backs to eat. The otters put their catch on their chests. Then they grab a rock. They use it to crack open the hard shells. This article is available at 5 reading levels at https://newsela.com. Habitat And Population It is hard to count marine otters. They like to live alone. So they are not usually seen in big groups. Scientists think there are not many left. They do not know the exact number. But they think there might be only 2,000 marine otters in the wild today. Sea otters live in water all the time. Marine otters are different. They live on land. They always live in rocky places close to water, though.
    [Show full text]
  • Biodiversity: the UK Overseas Territories. Peterborough, Joint Nature Conservation Committee
    Biodiversity: the UK Overseas Territories Compiled by S. Oldfield Edited by D. Procter and L.V. Fleming ISBN: 1 86107 502 2 © Copyright Joint Nature Conservation Committee 1999 Illustrations and layout by Barry Larking Cover design Tracey Weeks Printed by CLE Citation. Procter, D., & Fleming, L.V., eds. 1999. Biodiversity: the UK Overseas Territories. Peterborough, Joint Nature Conservation Committee. Disclaimer: reference to legislation and convention texts in this document are correct to the best of our knowledge but must not be taken to infer definitive legal obligation. Cover photographs Front cover: Top right: Southern rockhopper penguin Eudyptes chrysocome chrysocome (Richard White/JNCC). The world’s largest concentrations of southern rockhopper penguin are found on the Falkland Islands. Centre left: Down Rope, Pitcairn Island, South Pacific (Deborah Procter/JNCC). The introduced rat population of Pitcairn Island has successfully been eradicated in a programme funded by the UK Government. Centre right: Male Anegada rock iguana Cyclura pinguis (Glen Gerber/FFI). The Anegada rock iguana has been the subject of a successful breeding and re-introduction programme funded by FCO and FFI in collaboration with the National Parks Trust of the British Virgin Islands. Back cover: Black-browed albatross Diomedea melanophris (Richard White/JNCC). Of the global breeding population of black-browed albatross, 80 % is found on the Falkland Islands and 10% on South Georgia. Background image on front and back cover: Shoal of fish (Charles Sheppard/Warwick
    [Show full text]
  • Complete Issue
    ISSN 1023-9030 IUCN Otter Spec. Group Bull. 21 (2)/2004 IUCN OTTER SPECIALIST GROUP BULLETIN Volume 21 (2) October 2004 IUCN Otter Spec. Group Bull. 21(2) 2004 CONTENT Note from the Editor................................................................................................. 60 IUCN/SCC OSG GROUP In Memoriam Claus Reuther .................................................................................... 61 ARTICLES Assessing the Distribution of Reintroduced Populations of River Otters in 63 Pennsylvania (USA) – Development of a Landscape Level Approach .……………... First Physical Evidence of the Nearctic River Otter (Lontra canadensis) collected in 70 New Mexico, USA, since 1953 …………………………… ……………………….. High Mortality of Nearctic River Otters on a Florida, USA, Interstate Highway 76 during an Extreme Drought REPORTS Intraspecific Agonism between Giant Otters ……………………………………… 89 Preliminary Study of the Tracks of Captive Otters (Lutra lutra) as a Tool for Field Research ……………………………………………………………........................ 93 Literature..………………..............................................................................…....... 100 Congress Announcements.................................................................................….... 101 - 2 - IUCN Otter Spec. Group Bull. 21(2) 2004 IUCN OTTER SPECIALIST GROUP BULLETIN The IUCN Otter Specialist Group Bulletin appears biannually. Articles, reports, symposium announcements and information on recent publications are welcome. All submissions should be typed double-spaced. The submission
    [Show full text]
  • Iucn Red Data List Information on Species Listed On, and Covered by Cms Appendices
    UNEP/CMS/ScC-SC4/Doc.8/Rev.1/Annex 1 ANNEX 1 IUCN RED DATA LIST INFORMATION ON SPECIES LISTED ON, AND COVERED BY CMS APPENDICES Content General Information ................................................................................................................................................................................................................................ 2 Species in Appendix I ............................................................................................................................................................................................................................... 3 Mammalia ............................................................................................................................................................................................................................................ 4 Aves ...................................................................................................................................................................................................................................................... 7 Reptilia ............................................................................................................................................................................................................................................... 12 Pisces .................................................................................................................................................................................................................................................
    [Show full text]
  • The 2008 IUCN Red Listings of the World's Small Carnivores
    The 2008 IUCN red listings of the world’s small carnivores Jan SCHIPPER¹*, Michael HOFFMANN¹, J. W. DUCKWORTH² and James CONROY³ Abstract The global conservation status of all the world’s mammals was assessed for the 2008 IUCN Red List. Of the 165 species of small carni- vores recognised during the process, two are Extinct (EX), one is Critically Endangered (CR), ten are Endangered (EN), 22 Vulnerable (VU), ten Near Threatened (NT), 15 Data Deficient (DD) and 105 Least Concern. Thus, 22% of the species for which a category was assigned other than DD were assessed as threatened (i.e. CR, EN or VU), as against 25% for mammals as a whole. Among otters, seven (58%) of the 12 species for which a category was assigned were identified as threatened. This reflects their attachment to rivers and other waterbodies, and heavy trade-driven hunting. The IUCN Red List species accounts are living documents to be updated annually, and further information to refine listings is welcome. Keywords: conservation status, Critically Endangered, Data Deficient, Endangered, Extinct, global threat listing, Least Concern, Near Threatened, Vulnerable Introduction dae (skunks and stink-badgers; 12), Mustelidae (weasels, martens, otters, badgers and allies; 59), Nandiniidae (African Palm-civet The IUCN Red List of Threatened Species is the most authorita- Nandinia binotata; one), Prionodontidae ([Asian] linsangs; two), tive resource currently available on the conservation status of the Procyonidae (raccoons, coatis and allies; 14), and Viverridae (civ- world’s biodiversity. In recent years, the overall number of spe- ets, including oyans [= ‘African linsangs’]; 33). The data reported cies included on the IUCN Red List has grown rapidly, largely as on herein are freely and publicly available via the 2008 IUCN Red a result of ongoing global assessment initiatives that have helped List website (www.iucnredlist.org/mammals).
    [Show full text]
  • 1995-2006 Activities Report
    WILDLIFE WITHOUT BORDERS WILDLIFE WITHOUT BORDERS WITHOUT WILDLIFE M E X I C O The most wonderful mystery of life may well be EDITORIAL DIRECTION Office of International Affairs U.S. Fish & Wildlife Service the means by which it created so much diversity www.fws.gov PRODUCTION from so little physical matter. The biosphere, all Agrupación Sierra Madre, S.C. www.sierramadre.com.mx EDITORIAL REVISION organisms combined, makes up only about one Carole Bullard PHOTOGRAPHS All by Patricio Robles Gil part in ten billion [email protected] Excepting: Fabricio Feduchi, p. 13 of the earth’s mass. [email protected] Patricia Rojo, pp. 22-23 [email protected] Fulvio Eccardi, p. 39 It is sparsely distributed through MEXICO [email protected] Jaime Rojo, pp. 44-45 [email protected] a kilometre-thick layer of soil, Antonio Ramírez, Cover (Bat) On p. 1, Tamul waterfall. San Luis Potosí On p. 2, Lacandon rainforest water, and air stretched over On p. 128, Fisherman. Centla wetlands, Tabasco All rights reserved © 2007, U.S. Fish & Wildlife Service a half billion square kilometres of surface. The rights of the photographs belongs to each photographer PRINTED IN Impresora Transcontinental de México EDWARD O. WILSON 1992 Photo: NASA U.S. FISH AND WILDLIFE SERVICE DIVISION OF INTERNATIONAL CONSERVATION WILDLIFE WITHOUT BORDERS MEXICO ACTIVITIES REPORT 1995-2006 U.S. FISH AND WILDLIFE SERVICE At their roots, all things hold hands. & When a tree falls down in the forest, SECRETARÍA DE MEDIO AMBIENTE Y RECURSOS NATURALES MEXICO a star falls down from the sky. CHAN K’IN LACANDON ELDER LACANDON RAINFOREST CHIAPAS, MEXICO FOREWORD onservation of biological diversity has truly arrived significant contributions in time, dedication, and C as a global priority.
    [Show full text]
  • States of Emergency
    STATES OF EMERGENCY Technological Failures and Social Destabilization Patrick Lagadec Contents Introduction PART ONE Technical Breakdown, Crisis and Destabilization Framework of Reference 1. The weapons of crisis ........................................................................................ 11 1. An unusual event in a metastable context .......................................................... 12 2. Crisis dynamics................................................................................................... 21 2. Organizations with their backs to the wall...................................................... 23 1. Classic destabilization scenarios ......................................................................... 24 2. Slipping out of control ....................................................................................... 35 PART TWO Technological Crisis and the Actors Involved 3- In the thick of things ....................................................................................... 43 - Marc Becam ....................................................................................................... 45 The oil spill from the "Amoco Cadiz", March - May, 1978 - Richard Thornburgh........................................................................................... 55 Three Mile Island, March - April, 1979 - Douglas K. Burrows .......................................................................................... 66 The great Mississauga evacuation, November 10-16. 1979 - Péter-J.Hargitay ..............................................................................................
    [Show full text]
  • Marine Mammal Taxonomy
    Marine Mammal Taxonomy Kingdom: Animalia (Animals) Phylum: Chordata (Animals with notochords) Subphylum: Vertebrata (Vertebrates) Class: Mammalia (Mammals) Order: Cetacea (Cetaceans) Suborder: Mysticeti (Baleen Whales) Family: Balaenidae (Right Whales) Balaena mysticetus Bowhead whale Eubalaena australis Southern right whale Eubalaena glacialis North Atlantic right whale Eubalaena japonica North Pacific right whale Family: Neobalaenidae (Pygmy Right Whale) Caperea marginata Pygmy right whale Family: Eschrichtiidae (Grey Whale) Eschrichtius robustus Grey whale Family: Balaenopteridae (Rorquals) Balaenoptera acutorostrata Minke whale Balaenoptera bonaerensis Arctic Minke whale Balaenoptera borealis Sei whale Balaenoptera edeni Byrde’s whale Balaenoptera musculus Blue whale Balaenoptera physalus Fin whale Megaptera novaeangliae Humpback whale Order: Cetacea (Cetaceans) Suborder: Odontoceti (Toothed Whales) Family: Physeteridae (Sperm Whale) Physeter macrocephalus Sperm whale Family: Kogiidae (Pygmy and Dwarf Sperm Whales) Kogia breviceps Pygmy sperm whale Kogia sima Dwarf sperm whale DOLPHIN R ESEARCH C ENTER , 58901 Overseas Hwy, Grassy Key, FL 33050 (305) 289 -1121 www.dolphins.org Family: Platanistidae (South Asian River Dolphin) Platanista gangetica gangetica South Asian river dolphin (also known as Ganges and Indus river dolphins) Family: Iniidae (Amazon River Dolphin) Inia geoffrensis Amazon river dolphin (boto) Family: Lipotidae (Chinese River Dolphin) Lipotes vexillifer Chinese river dolphin (baiji) Family: Pontoporiidae (Franciscana)
    [Show full text]
  • Marine Pollution and the Toxic Legacy of Our Consumer Culture
    Marine Pollution: The Toxic Legacy of Our Consumer Culture Dr. Susan D. Shaw Marine & Environmental Research Institute School of Public Health, University at Albany, NY GEO Blue Planet Symposium College Park, MD May 31-June 2, 2017 Greenhouse Gases Convergence of Stress . Alteration of climate & ocean chemistry . Oceans warming (store 9/10 of heat trapped by greenhouse gases), melting ice at poles . Acidification (CO2) = loss of corals by 2050 . Toxicity increasing – increasing pollutant distribution, potency (metabolism) . Species extinctions . Sea level rise, extreme weather, human displacement “Living Better With Chemistry.” DDT c. 1949 Petrochemicals and plastics post WWII Glenbow Archives NA-5600-6671a Dilution Is The Solution © Xanthe Rivett / CAFNEC / WWF-Aus The Plastic Sea By 2050 the oceans could contain more plastic than fish by weight 8 billion pieces of plastic enter the oceans every year The Problem of Plastics . 46,000 pieces per sq mile of ocean . Degrade to microplastics, last 100+ years . Contain and adsorb toxic chemicals (PCBs, phthalates, flame retardants) . Eaten by fish, then peope, effects uncertain Entanglement in Plastic Flame Retardants (PBDEs, polybrominated diphenyl ethers) Clothing, textiles, mattresses, upholstery, TVs, computers, plastics, electronics, building materials, house dust and food Endocrine disruptors, IQ loss in children, cancer Perfluorinated Chemicals (PFCs) Stain-and water resistant coatings on food wrappers, outdoor wear, non-stick pans, also in fire-fighting foams Endocrine disruptors, cancer Newly discovered flame retardants in Mariana Trench amphipods Flame Retardants in Pinnipeds Harbor seal (Phoca vitulina ) Sea lion (Zalophus californianus) Gray seal (Halichoerus grypus) Shaw et al. 2008, Meng et al. 2009, Law et Meng et al.
    [Show full text]
  • THE PINNIPEDS of the CALIFORNIA CURRENT California
    ANTONELIS AND FISCUS: PINNIPEDS OF THE CALIFORNIA CURRENT CalCOFI Rep., Vol. XXI, 1980 THE PINNIPEDS OF THE CALIFORNIA CURRENT GEORGE A. ANTONELIS. JR. AND CLIFFORD H. FISCUS Marine Mammal Division Northwest and Alaska Fisheries Center National Marine Fisheries Service National Oceanic and Atmospheric Administration 7600 Sand Point Way, N.E. Seattle, WA 981 15 ABSTRACT 10s pequenos peces en 10s cardumenes y peces ana- There are six species of pinnipeds-California sea dromos. Los dos focidos, otra vez con ciertas excep- lion, Zalophus californianus; northern sea lion, Eume- ciones, predan especies diferentes. Aparentemente, el topias jubatus; northern fur seal, Callorhinus ursinus; elefante marino se alimenta en aguas mas profundas que Guadalupe fur seal, Arctocephalus townsendi; harbor la foca peluda, alimentindose de especies demersales seal, Phoca uitulina richardsi; and northern elephant y benticas, y la foca peluda se alimenta de especiesdemer- seal, Mirounga angustirostris-that inhabit the study sales costeras y neriticas, entrando ocasionalmente en rios area of the California Cooperative Oceanic Fisheries y aguas estuarinas haciendopresa de 10s peces anadromos Investigations (CalCOFI). y otros pequeiios peces que entran regularmente en estas The numbers of animals in each population are given; aguas. the size, distribution, and seasonal movements are de- scribed. The known prey species of the pinnipeds are INTRODUCTION listed for each species. The otariids, with certain excep- The California Current, its components, and the Cali- tions, consume the same kinds of prey, although in slight- fornia Cooperative Oceanic Fisheries Investigations ly different amounts. In general they feed most commonly (CalCOFI) station plan have been described many times on the smaller schooling fishes and squids of the epi- in the past and are well known (Kramer et al.
    [Show full text]
  • Life History Account for Guadalupe Fur-Seal
    California Wildlife Habitat Relationships System California Department of Fish and Wildlife California Interagency Wildlife Task Group GUADALUPE FUR-SEAL Arctocephalus townsendi Family: OTARIIDAE Order: CARNIVORA Class: MAMMALIA M168 Written by: M. L. Riedman Reviewed by: H. Shellhammer Edited by: J. Harris, R. Duke DISTRIBUTION, ABUNDANCE, AND SEASONALITY Guadalupe fur seals are rarely observed in California. Their entire breeding population is centered on Isla de Guadalupe, 256 km (159 mi) west of Baja California, Mexico. Occasionally they occur on San Miguel Island, San Nicolas Island, and once, on San Clemente Island in southern California. One adult male maintained a territory among breeding California sea lions on San Miguel Island (DeLong 1975, Le Boeuf et al. 1976). In 1938, 3 young males were sighted at Piedras Blancas in San Luis Obispo Co. (Bonnot et al. 1938). Before exploitation, Guadalupe fur seals bred on other Mexican islands, Channel Islands, and possibly on Farallon Islands (Hubbs 1956, Bartholomew 1967, Fleischer 1978a, Walker and Craig 1979). Commercially hunted nearly to extinction in the 1800's, only 7 individuals were observed on Isla de Guadalupe in 1892 (Townsend 1899). Subsequent recovery has been slow; the current population is estimated at 2000 (Pierson 1978, Le Boeuf and Bonnell 1980). Inhabits rocky insular shorelines; often found in sheltered crevices and sea caves. Rarely observed at sea. SPECIFIC HABITAT REQUIREMENTS Feeding: Little information. Appear to feed opportunistically on a variety of fish and invertebrates, particularly on rockfish at Isla de Guadalupe (Fleischer 1978b, Bonner 1981). Cover: Found in shallow, nearshore island waters. Prefer cool and sheltered rocky habitats along steep shelving shorelines.
    [Show full text]