The Secret Life of Marine Mammals

Total Page:16

File Type:pdf, Size:1020Kb

The Secret Life of Marine Mammals FEATURE THE SECRET LIFE OF MARINE MAMMALS NOVEL TOOLS FOR STUDYING THEIR BEHAVIOR AND BIOLOGY AT SEA By Daniel P. Costa Given the interest by both the lay and sci- on the diving performance of marine mammals entific communities, it is surprising how little is (Kooyman 1989: Costa 1991a,b). Typically these known about the open ocean ecology of marine devices are attached to the animal (using a harness mammals. Their patchy distribution and low or glue; Fig. 1), and the data are retrieved when abundance leads to infrequent encounters at sea. the device is recovered after recapture of the ani- Most of our information on marine mammals has mal. The need to recapture the animal limits this been obtained from shipboard or aerial observa- system, but it has been used quite successfully on tions, which provide a very limited perspective studies of pinnipeds (sea lions, fur seals, and on their life at or near the surface, with little in- seals). An example of a time-depth record obtained sight into their behavior under the water where for an Australian sea lion is shown in Figure 2. they spend up to 90% of their time. Recent ad- A summary of the diving data obtained indicates vances in technology are providing an opportu- that the "true" or earless seals (Phocidae) are capa- nity to gain new insights into the underwater ble of deeper longer dives than sea lions and fur lives of marine mammals. Preliminary informa- seals (Otariidae: Fig. 3). These differences reflect tion indicates that marine mammal distribution optimization for exploitation of different habitats and resources (Costa, 1993). Sea lions and fur seals • . technologies and abundance is highly correlated with oceanic features like frontal systems, thermocline depth, feed on vertically moving prey that approach the now available on bathymetry, eddies, jets, and warm core rings. surface, whereas true seals feed on sedentary ben- thic or midwater prey. The considerable difference under development These features concentrate or aggregate prey, between mean dive depth/duration and maximum permitting effective predation. The technologies dive depth/duration suggests that seals and sea lions will enable an now available or under development will enable rarely reach their physiological limit with respect to an examination of how oceanic features and examination of how dive depth or duration. Other factors such as prey processes affect marine mammal biology. This type, depth, and availability determine the optimal oceanic features and article summarizes some of the novel technolo- diving pattern, and prey availability is directly re- gies that are currently available or under devel- processes affect lated to oceanic features and processes. opment. It is hoped that an increased awareness Coordination of data on diving pattern with in- marine mammal of the research potential of these approaches will formation on prey species indicates that prey size, stimulate interdisciplinary collaborations between biology. behavior, and energy content influence the forag- marine mammal biologists, fisheries biologists, ing pattern employed (Costa, 1991a,b). The most and physical and biological oceanographers. detailed study of foraging behavior carried out on Recoverable Data Loggers Antarctic fur seals (Croxall et al.. 1985), showed Recoverable multichannel digital data loggers that these seals made most (75%) of their dives at are available with variable sampling rates that night, when dives were consistently shallower record depth, light level, water temperature, swim (<30 m) than dives during the daytime (mostly velocity, and surface location. The first instruments 40-75 m). This pattern closely followed the verti- to be deployed measured dive depth as a function cal distribution of krill, which during daylight of time and have provided a wealth of information hours was below a depth of 50 m and at night was present in substantial quantities above 50 m. Even though >40% of the krill was below 75 m depth at all times of the day, fur seal dives seldom (3%) D.P. Costa, Life Sciences Department, Office of Naval Re- exceeded this depth. The authors concluded that search, 800 N. Quincy St.. Arlington VA 22217 and Biology krill are captured only from shallow depths, since Department, University of California, Santa Cruz, CA 95064, USA. this is when they are most efficiently obtained. 120 OCEANOGRAPHY*VoI.6, NO. 3"1993 Fig. 1: An Australian sea lion female with a Wildlife Computers time-depth recorder glued to the hair on her back. In a similar study it was found that female squid to move into shallow water before preying northern fur seals exhibit distinct diving patterns on them. specific to the type of prey consumed. During a The most impressive data obtained so far on foraging trip (typically lasting 7 days), an indi- pinniped diving behavior come from studies of vidual northern fur seal female exhibited one of northern and southern elephant seals (Le Boeuf the following dive patterns: those composed ex- and Laws, 1994). Northern elephant seals dive clusively of deep dives with a mean depth of 185 continuously, day and night, for the entire trip to m, those composed exclusively of shallow dives sea, which lasts between 2 and 8 months (Fig. Deep-diving with a mean depth of 50-60 m, and those with a 4). Two-month trips are associated with females mixture of both deep and shallow dives (Gentry who have just completed lactation and are re- northern fur seals did and Kooyman, 1986). Deep-diving northern fur turning to molt, whereas the 8-month foraging not exhibit diurnal seals did not exhibit diurnal fluctuations in div- trip follows the molting period and is when ges- ing depth, which implied that they were feeding tation occurs. While at sea, they spend 90% of fluctuations in diving on demersal or benthic species, whereas shallow their time underwater, with dives averaging 20 depth .... divers exhibited a striking diurnal fluctuation in minutes (maximum dives in excess of ~ hr) fol- diving pattern quite similar to that observed for lowed by surface intervals of less than 3 min- Antarctic fur seals eating krill. A subsequent utes. Their diving patterns follow a diurnal cycle study using a combination of time-depth recorder with the deepest dives occurring during the day and VHF telemetry determined that deep-diving and shallowest at night. Modal dive depths are fur seals feed on demersal fish such as pollock 300-600 m with maximum dives exceeding on the Bering Sea shelf, whereas shallow-diving 1,500 m! fur seals feed on vertically migrating squid over Recently, the track of elephant seals during deep water beyond the Bering Sea shelf (Goebel these foraging trips have been determined by mea- et al., 1991). Like krill, squid are available surements of light level and water temperature throughout the day, and like krill-consuming while they are at the surface. Location is calculated Antarctic fur seals, northern fur seals wait for by extrapolation of light levels to provide time of OCEANOGRAPHY'Vo1.6, NO. 3"1993 121 20:00 . _ . 24:00 northeastern Pacific, as far as 150°W (about due north of the Hawaiian Islands), in the range 8E 4 44-52°N (De Long et al., 1992) (Fig. 5). Although these results are impressive, they B0 L_ _ I ._ • O0 O0 04.00 have yet to be integrated into models that relate animal location and behavior with oceanographic phenomena such as frontal systems, eddies, up- welling zones, warn] core rings, and thermoclines. 04.00 O0 However, one recent study on southern elephant seals used a time-depth recorder that incorporated data on water temperature (Boyd and Arnbom, 08 O0 1991). An elephant seal was observed to descend rapidly to the discontinuity between cold surface water and warmer deep water. The animal spent a • . marine mammal substantial amount of its time (57%) at or near the 12 O0 thermocline indicating the likelihood that it was distribution, foraging there. Further, the structure of the water abundance, and mass indicated that the animal was foraging south of the Antarctic Polar Front. Ultimately marine behavior is related to 16 O0 mammal distribution, abundance, and behavior is the oceanographic related to the oceanographic factors that determine prey distribution. Our understanding of this rela- factors that determine 2O oo tionship is limited and is thus a fertile area for in- prey distribution. vestigation. Significant insights have been gained from data on time and depth and additional sensors are being oo'oq 04 o0 incorporated into the devices. For example, inves- tigators are looking for ways to incorporate pre- cise information on location derived from the Global Positioning System Satellite (GPS). Equip- ment is being designed and tested that would allow the data logger to be released from the ani- I I I mal upon command from a radio transmitter, or 08:00 . -2:00 permit stored data to be recovered via short-range radio or acoustic telemetry. Data loggers currently available can record at-sea location (within 40 P 12:00 16:00 km), dive frequency and profile, swim velocity, heart rate, and water temperature. Other sensors that can measure and record information on ambi- ............... ...... ' ..... t I I .__ | ent acoustic environment, ocean structure (salin- ity), and feeding behavior are being tested or are Fig. 2: The diving pattern (dive depth versus time) under development• over a complete 42-h foraging trip obtained.from an Australian sea lion female (from departure to return to shore). Time is divided into 4-h blocks Dive duration (min) and depth extends j~kom 0 to 80 meters. 10 100 ,o ......... 100 sunrise, sunset, and local apparent noon. Latitude 300 A is calculated from day length, and longitude from 500 .£ local apparent noon as referenced to Greenwich Jc 700 mean time (DeLong et al., 1992)• Previously, it had o been assumed that northern elephant seals existed 900 in offshore waters from California to British Co- 1100 00tariids lumbia.
Recommended publications
  • Chapter 20: Protecting Marine Mammals and Endangered Marine Species
    Preliminary Report CHAPTER 20: PROTECTING MARINE MAMMALS AND ENDANGERED MARINE SPECIES Protection for marine mammals and endangered or threatened species from direct impacts has increased since the enactment of the Marine Mammal Protection Act in 1972 and the Endangered Species Act in 1973. However, lack of scientific data, confusion about permitting requirements, and failure to adopt a more ecosystem-based management approach have created inconsistent and inefficient protection efforts, particularly from indirect and cumulative impacts. Consolidating and coordinating federal jurisdictional authorities, clarifying permitting and review requirements for activities that may impact marine mammals and endangered or threatened species, increasing scientific research and public education, and actively pursuing international measures to protect these species are all improvements that will promote better stewardship of marine mammals, endangered or threatened species, and the marine ecosystem. ASSESSING THE THREATS TO MARINE POPULATIONS Because of their intelligence, visibility and frequent interactions with humans, marine mammals hold a special place in the minds of most people. Little wonder, then, that mammals are afforded a higher level of protection than fish or other marine organisms. They are, however, affected and harmed by a wide range of human activities. The biggest threat to marine mammals worldwide today is their accidental capture or entanglement in fishing gear (known as “bycatch”), killing hundreds of thousands of animals a year.1 Dolphins, porpoises and small whales often drown when tangled in a net or a fishing line because they are not able to surface for air. Even large whales can become entangled and tow nets or other gear for long periods, leading to the mammal’s injury, exhaustion, or death.
    [Show full text]
  • Download Transcript
    SCIENTIFIC AMERICAN FRONTIERS PROGRAM #1503 "Going Deep" AIRDATE: February 2, 2005 ALAN ALDA Hello and welcome to Scientific American Frontiers. I'm Alan Alda. It's said that the oceans, which cover more than two thirds of the earth's surface, are less familiar to us than the surface of the moon. If you consider the volume of the oceans, it's actually more than ninety percent of the habitable part of the earth that we don't know too much about. The main reason for our relative ignorance is simply that the deep ocean is an absolutely forbidding environment. It's pitch dark, extremely cold and with pressures that are like having a 3,000-foot column of lead pressing down on every square inch -- which does sound pretty uncomfortable. In this program we're going to see how people finally made it to the ocean floor, and we'll find out about the scientific revolutions they brought back with them. We're going to go diving in the Alvin, the little submarine that did so much of the work. And we're going to glimpse the future, as Alvin's successor takes shape in a small seaside town on Cape Cod. That's coming up in tonight's episode, Going Deep. INTO THE DEEP ALAN ALDA (NARRATION) Woods Hole, Massachusetts. It's one of the picturesque seaside towns that draw the tourists to Cape Cod each year. But few seaside towns have what Woods Hole has. For 70 years it's been home to the Woods Hole Oceanographic Institution — an organization that does nothing but study the world's oceans.
    [Show full text]
  • Issue 1, Dec 2019 Distribution and Abundance in India
    OCEAN DIGEST Quarterly Newsletter of the Ocean Society of India Volume 6 | Issue 1 | Dec 2019 | ISSN 2394-1928 Ocean Digest Quarterly Newsletter of the Ocean Society of India Marine Mammals — Indian Scenario Chandrasekar Krishnamoorthy Centre for Marine Living Resources & Ecology Ministry of Earth Sciences, Kochi arine mammals, the most amazing marine organisms on earth, are often referred to as “sentinels” of ocean Porpoising - Striped dolphin health.M These include approximately 127 species belonging to three major taxonomic orders, namely Cetacea (whales, dolphins, and porpoises), Sirenia (manatees and dugong) and Carnivora (sea otters, polar bears and pinnipeds) (Jefferson et al., 2008). These organisms are known to inhabit oceans and seas, as well as estuaries, and are distributed from the polar to the tropical regions. These organisms are the top predators in many ocean food webs except the sirenians, which are herbivores. However, cetaceans become the dominant group of marine mammals, as well as widest geographic range. Marine mammals have been deemed “invaluable components” of the naval force as their natural senses are superior to technology in rough weather and noisy areas. India, with a rich diversity of marine mammals has a history of documenting these animals for the last 200 years. Leaping - Spinner dolphin However, until the year 2003, information on these organisms in our seas was restricted to incidental capture by fishing gears and stranding records (Vivekanandan and Jeyachandran, 2012). Published reports indicate that only a few scientific studies have addressed the distribution of marine mammals in the Indian EEZ, and there exist huge lacunae on the baseline information such as abundance and density for many species due to limited resources and lack of systematic surveys.
    [Show full text]
  • THE CASE AGAINST Marine Mammals in Captivity Authors: Naomi A
    s l a m m a y t T i M S N v I i A e G t A n i p E S r a A C a C E H n T M i THE CASE AGAINST Marine Mammals in Captivity The Humane Society of the United State s/ World Society for the Protection of Animals 2009 1 1 1 2 0 A M , n o t s o g B r o . 1 a 0 s 2 u - e a t i p s u S w , t e e r t S h t u o S 9 8 THE CASE AGAINST Marine Mammals in Captivity Authors: Naomi A. Rose, E.C.M. Parsons, and Richard Farinato, 4th edition Editors: Naomi A. Rose and Debra Firmani, 4th edition ©2009 The Humane Society of the United States and the World Society for the Protection of Animals. All rights reserved. ©2008 The HSUS. All rights reserved. Printed on recycled paper, acid free and elemental chlorine free, with soy-based ink. Cover: ©iStockphoto.com/Ying Ying Wong Overview n the debate over marine mammals in captivity, the of the natural environment. The truth is that marine mammals have evolved physically and behaviorally to survive these rigors. public display industry maintains that marine mammal For example, nearly every kind of marine mammal, from sea lion Iexhibits serve a valuable conservation function, people to dolphin, travels large distances daily in a search for food. In learn important information from seeing live animals, and captivity, natural feeding and foraging patterns are completely lost.
    [Show full text]
  • Marine Mammals and Sea Turtles of the Mediterranean and Black Seas
    Marine mammals and sea turtles of the Mediterranean and Black Seas MEDITERRANEAN AND BLACK SEA BASINS Main seas, straits and gulfs in the Mediterranean and Black Sea basins, together with locations mentioned in the text for the distribution of marine mammals and sea turtles Ukraine Russia SEA OF AZOV Kerch Strait Crimea Romania Georgia Slovenia France Croatia BLACK SEA Bosnia & Herzegovina Bulgaria Monaco Bosphorus LIGURIAN SEA Montenegro Strait Pelagos Sanctuary Gulf of Italy Lion ADRIATIC SEA Albania Corsica Drini Bay Spain Dardanelles Strait Greece BALEARIC SEA Turkey Sardinia Algerian- TYRRHENIAN SEA AEGEAN SEA Balearic Islands Provençal IONIAN SEA Syria Basin Strait of Sicily Cyprus Strait of Sicily Gibraltar ALBORAN SEA Hellenic Trench Lebanon Tunisia Malta LEVANTINE SEA Israel Algeria West Morocco Bank Tunisian Plateau/Gulf of SirteMEDITERRANEAN SEA Gaza Strip Jordan Suez Canal Egypt Gulf of Sirte Libya RED SEA Marine mammals and sea turtles of the Mediterranean and Black Seas Compiled by María del Mar Otero and Michela Conigliaro The designation of geographical entities in this book, and the presentation of the material, do not imply the expression of any opinion whatsoever on the part of IUCN concerning the legal status of any country, territory, or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The views expressed in this publication do not necessarily reflect those of IUCN. Published by Compiled by María del Mar Otero IUCN Centre for Mediterranean Cooperation, Spain © IUCN, Gland, Switzerland, and Malaga, Spain Michela Conigliaro IUCN Centre for Mediterranean Cooperation, Spain Copyright © 2012 International Union for Conservation of Nature and Natural Resources With the support of Catherine Numa IUCN Centre for Mediterranean Cooperation, Spain Annabelle Cuttelod IUCN Species Programme, United Kingdom Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the sources are fully acknowledged.
    [Show full text]
  • Exploration of the Deep Gulf of Mexico Slope Using DSV Alvin: Site Selection and Geologic Character
    Exploration of the Deep Gulf of Mexico Slope Using DSV Alvin: Site Selection and Geologic Character Harry H. Roberts1, Chuck R. Fisher2, Jim M. Brooks3, Bernie Bernard3, Robert S. Carney4, Erik Cordes5, William Shedd6, Jesse Hunt, Jr.6, Samantha Joye7, Ian R. MacDonald8, 9 and Cheryl Morrison 1Coastal Studies Institute, Louisiana State University, Baton Rouge, Louisiana 70803 2Department of Biology, Penn State University, University Park, Pennsylvania 16802-5301 3TDI Brooks International, Inc., 1902 Pinon Dr., College Station, Texas 77845 4Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, Louisiana 70803 5Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, Massachusetts 02138 6Minerals Management Service, Office of Resource Evaluation, New Orleans, Louisiana 70123-2394 7Department of Geology, University of Georgia, Athens, Georgia 30602 8Department of Physical and Environmental Sciences, Texas A&M – Corpus Christi, Corpus Christi, Texas 78412 9U.S. Geological Survey, 11649 Leetown Rd., Keameysville, West Virginia 25430 ABSTRACT The Gulf of Mexico is well known for its hydrocarbon seeps, associated chemosyn- thetic communities, and gas hydrates. However, most direct observations and samplings of seep sites have been concentrated above water depths of approximately 3000 ft (1000 m) because of the scarcity of deep diving manned submersibles. In the summer of 2006, Minerals Management Service (MMS) and National Oceanic and Atmospheric Admini- stration (NOAA) supported 24 days of DSV Alvin dives on the deep continental slope. Site selection for these dives was accomplished through surface reflectivity analysis of the MMS slope-wide 3D seismic database followed by a photo reconnaissance cruise. From 80 potential sites, 20 were studied by photo reconnaissance from which 10 sites were selected for Alvin dives.
    [Show full text]
  • Marine Mammals of the US North Pacific & Arctic
    Marine Mammals of the US North Pacific & Arctic 10 METER 0 10 FEET adult male Resident Killer Whale Blue Whale Orcinus orca subsp. Balaenoptera musculus adult female calf Bigg’s (transient) Killer Whale Orcinus orca subsp. Fin Whale Balaenoptera physalus Beluga or White Whale Delphinapterus leucas Sei Whale Balaenoptera borealis Sperm Whale Physeter macrocephalus adult female North Pacific Right Whale adult male Eubalaena japonica Baird’s Beaked Whale Berardius bairdii Minke Whale Balaenoptera acutorostrata Bowhead Whale Balaena mysticetus Cuvier’s Beaked Whale Ziphius cavirostris adult male Gray Whale Humpback Whale Eschrichtius robustus Megaptera novaeangliae adult female 180º 160ºW 140ºW calf ARCTIC OCEAN Marine Mammal Protection Act (MMPA) Stejneger’s Beaked Whale Beaufort Mesoplodon stejnegeri Sea In 1972, Congress enacted the NOAA Fisheries and the U.S. Fish and Wildlife Service are Chukchi 70ºN the lead federal agencies for enforcing this law to protect Design and illustrations: Uko Gorter (www.ukogorter.com) Sea MMPA, establishing a national Arctic Circle marine mammals. The MMPA protects all whales, dolphins, Alaska policy to help prevent the seals, sea lions, porpoises, manatees, polar bears, otters, NOAA Fisheries extinction or depletion of and walruses from human-induced harm. In the United Alaska Region States, NOAA Fisheries works with scientists, industry, and 60ºN 907-586-7221 Bering Sea Gulf of marine mammal populations conservation groups to develop measures that help to protect Alaska Alaska Fisheries Science Center from human activities. marine mammals from entanglement, ship strike, and other 206-526-4000 PACIFIC OCEAN activities that might cause these animals harm. TO REPORT STRANDED, ENTANGLED, INJURED, OR DEAD MARINE MAMMALS, CALL: NOAA FISHERIES 1-877-925-7773; ALASKA SEALIFE CENTER 1-888-774-7325 (SEAL); U.S.
    [Show full text]
  • Challenges of Diving to Depth
    background sheet Challenges of diving to depth Photo by Jess © Australian Antarctic Division To harvest rich food resources of oceans, air- oxygen is stored in blood and muscle of diving mammals, breathing animals not only need to swim, they need and 35-60% in diving birds. to dive. Unlike fish, which have gills, air-breathing Reptiles are ectotherms, with much lower metabolic rates animals can’t extract oxygen from water. Instead than endotherms. Research into oxygen storage capacities these animals must regularly come to the surface to of reptiles is limited, influenced by the fact that some species breathe. are capable of cutaneous respiration (respiration through skin), enabling direct uptake of oxygen from water. Oxygen storage in the respiratory system Many deep-diving animals have lung capacities similar to terrestrial animals, indicating that their respiratory systems are not the predominant oxygen store. In many species, particularly whales, decreased lung volume correlates with increased dive depth. Some terrestrial diving animals, including sea otters and diving rodents, have large lungs that provide an important oxygen store. Sea otters store 55% of their oxygen in their lungs. Diving to depth with a large respiratory oxygen store can cause hyperbaric problems such as decompression sickness. However, sea otters are not deep divers, routinely diving to only a few metres. Oxygen storage in blood Diving animals store a significant proportion of oxygen in their blood. Oxygen storage in blood depends on an oxygen-binding protein, haemoglobin. Haemoglobin carries oxygen from the lungs to the rest of the body. The more haemoglobin present in blood, the more oxygen is bound and delivered to the body.
    [Show full text]
  • WOODS HOLE OCEANOGRAPHIC INSTITUTION Deep-Diving
    NEWSLETTER WOODS HOLE OCEANOGRAPHIC INSTITUTION AUGUST-SEPTEMBER 1995 Deep-Diving Submersible ALVIN WHOI Names Paul Clemente Sets Another Dive Record Chief Financial Officer The nation's first research submarine, the Deep Submergence Paul CI~mente, Jr., a resident of Hingham Vehicle (DSV) Alvin. passed another milestone in its long career and former Associate Vice President for September 20 when it made its 3,OOOth dive to the ocean floor, a Financial Affairs at Boston University, as· record no other deep-diving sub has achieved. Alvin is one of only sumed his duties as Associate Director for seven deep-diving (10,000 feet or more) manned submersibles in the Finance and Administration at WHOI on world and is considered by far the most active of the group, making October 2. between 150 and 200 dives to depths up to nearly 15,000 feet each In his new position Clemente is respon· year for scientific and engineering research . sible for directing all business and financial The 23-1001, three-person submersible has been operated by operations of the Institution, with specifIC Woods Hole Oceanographic Institution since 1964 for the U.S. ocean resp:>nsibility for accounting and finance, research community. It is owned by the OffICe of Naval Research facilities, human resources, commercial and supported by the Navy. the National Science Foundation and the affairs and procurement operations. WHOI, National Oceanic and Atmospheric Administration (NOAA). Alvin the largest private non· profit marine research and its support vessel, the 21 0-100t Research Vessel Atlantis II, are organization in the U.S., has an annual on an extended voyage in the Pacific which began in January 1995 operating budget of nearly $90 million and a with departure from Woods Hole.
    [Show full text]
  • Marine Bioluminescence: Measurement by a Classical Light Sensor and Related Foraging Behavior of a Deep Diving Predator†
    Photochemistry and Photobiology, 2017, 93: 1312–1319 Marine Bioluminescence: Measurement by a Classical Light Sensor and Related Foraging Behavior of a Deep Diving Predator† Jade Vacquie-Garcia* ‡1,Jer ome^ Mallefet2,Fred eric Bailleul3, Baptiste Picard1 and Christophe Guinet1 1Centre d’Etudes Biologiques de Chize, CNRS, Villiers en Bois, France 2Universite catholique du Louvain, UCL, Louvain-la-Neuve, Belgique 3South Australian Research and Development Institute (Aquatic Sciences), Adelaide, SA, Australia Received 11 September 2016, accepted 14 March 2017, DOI: 10.1111/php.12776 ABSTRACT Bioluminescence is produced by a broad range of organisms function) (1,3). The defensive function, the most common use of for defense, predation or communication purposes. Southern bioluminescence, takes many forms such as startling, sacrificial elephant seal (SES) vision is adapted to low-intensity light lure or counter illumination (i.e. the silhouette of an animal seen with a peak sensitivity, matching the wavelength emitted by by a predator coming from under is concealed by the ventral biolu- myctophid species, one of the main preys of female SES. A minescence of same color, intensity and angular distribution of the total of 11 satellite-tracked female SESs were equipped with residual ambient light). However, bioluminescence emitted by an a time-depth-light 3D accelerometer (TDR10-X) to assess organism can also be “diverted” by others organisms not targeted whether bioluminescence could be used by SESs to locate by the emissions; in that case, the beneficiary of the emissions their prey. Firstly, we demonstrated experimentally that the might not be the emitter (e.g. a visual predator taking advantage of TDR10-X light sensor was sensitive enough to detect natural the bioluminescence emitted by the prey to catch it).
    [Show full text]
  • Chapter 7 MARINE MAMMAL PROGRAM
    Marine Mammal Program Chapter 7 MARINE MAMMAL PROGRAM KAMALA J. RAPP-SANTOS, DVM, MPH, DACVPM* INTRODUCTION HISTORY AND BACKGROUND OF THE MILITARY MARINE MAMMAL PROGRAM The Evolving Marine Mammal Program The Evolving Roles of Marine Mammals in the Program The Evolving Roles of Military Veterinarians in the Program CURRENT MILITARY OBJECTIVES AND MISSIONS IN THE MARINE MAMMAL PROGRAM Marine Mammal Systems Using Bottlenose Dolphins Marine Mammal Systems Using California Sea Lions Healthcare Research Furthering Marine Mammal Understanding PREVENTIVE MEDICINE FOCUS FOR MILITARY MARINE MAMMAL HEALTH Physical Examinations and Health Monitoring Sanitation and Nutrition Oversight Data and Tissue Collection and Management Deployment Support Development of Advanced Clinical Technology Environmental Health Monitoring Emphasis on Education CURRENT RELEVANT MARINE MAMMAL DISEASES Respiratory Disease in Dolphins Ocular Disease in Sea Lions Metabolic Conditions in Dolphins Gastritis in Dolphins and Sea Lions SUMMARY *Major, Veterinary Corps, United States Army; currently, Laboratory animal medicine resident at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland 21702; formerly, Captain, Veterinary Corps, US Army, Clinical Veterinarian, US Navy Marine Mammal Program, San Diego, California 175 Military Veterinary Services INTRODUCTION The US Navy Marine Mammal Program (MMP), equipment, despite the challenges of marine mammal located in San Diego, California, maintains a large medicine. For example,
    [Show full text]
  • DEEP STOPS and DEEP HELIUM RGBM Technical Series 9 Bruce R
    DEEP STOPS AND DEEP HELIUM RGBM Technical Series 9 Bruce R. Wienke and Timothy R. O’Leary NAUI Technical Diving Operations Tampa, Florida 33619 BASICS Deep stops – what are they? Actually, just what the name suggests. Deep stops are decompression stops made at deeper depths than those traditionally dictated by classical (Haldane) dive tables or algorithms. They are fairly recent (last 15 years) protocols, suggested by modern decompression theory, but backed up by extensive diver practicum with success in the mixed gas and decompression arenas - so called technical diving. Tech diving encompasses scientific, military, commercial, and exploration underwater activities. The impact of deep stops has been a revolution in diving circles. So have slower ascent rates across recreational and technical diving. In quantifiable terms, slower ascent rates are very much akin to deep stops, though not as pronounced as decompression stops. Deep stops plus slow ascent rates work together. And they work together safely and efficiently. Many regard deep stops as a most significant development in modern diving. Here’s why. Deep stops usually reduce overall decompression time (hang time) too. And when coupled to the use of helium in the breathing mixture (trimix) to reduce narcotic effects of nitrogen, technical divers report feeling much better physically today when they leave the water. The reduction in hang time ranges from 10% to as high as 50%, depending on diver, mix, depth, and exposure time. Feeling better while decompressing for shorter periods of time is certainly a win-win situation that would have been thought an impossibility not too long ago.
    [Show full text]