DOCSLIB.ORG

Aspects of the Life History of the Blue Shark, Prionace Glauca L., in Monterey Bay, California

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Aspects of the Life History of the Blue Shark, Prionace Glauca L., in Monterey Bay, California MLML/ MBARIUBRARY 8272 MOSS LANDING RD. MOSS LANDING, Gil 95039 ASPECTS OF THE LIFE HISTORY OF THE BLUE SHARK, PRIONACE GLAUCA L., IN MONTEREY BAY, CALIFORNIA A Thesis .Presented to the Faculty of the Department of Biology San Jose State University ( In Partial Fulfillment of the Requirements for the Degree Masters of Arts By James Thomas Harvey December, 1979 ABSTRACT.--Feeding habit, age structure, growth, morphology, and parasite data were collected on the seasonally abundant blue shark, Prionace glauca, in Monterey Bay, California from 1974 to 1977. Stomach content analysis of 150 blue sharks revealed a diet which was dominated by the northern anchovy (Engraulis mordax), euphausiids (mainly ~anoessa spinifera), hake (Merluccius productus), and several species of cephalopods. The ingestion of l· spinifera marks the first record of preda­ tion upon euphausiids by this species. In general, the rna- jority of prey live an epipelagic life or become epipelagic nocturnally. The blue sharks ranged in total length from 98.5 to 204.5 em (x = 155.6! 3.9 em). Females were signifi­ cantly more numerous (124 females:24 males) and of greater age than males. Vertebral ring counts of 98 blue sharks showed the estimated age of sampled sharks to be 2 to 6 years. Length frequency data tends to support the assumption of an­ nular ring formation. Aging and length frequency data es­ timate growth rates of 12.2-28.2 cm/yr, the higher growth rates occurring at the younger ages. Only the linear mea- surements associated with the head region changed significantly when compared to the total length for the 115 sharks examined for allometric growth. Liver weights, gonad weights, and parasite relationships were also discussed. l' i i i • I' i' TABLE OF CONTENTS Page ABSTRACT ... i i i LIST OF TABLES vi LIST OF FIGURES. v i i i ACKNOWLEDGEMENTS X I NT ROD UCT! ON . 1 MATERIALS AND METHODS. 8 RESULTS. 1 8 Length. 1 8 Allometric growth 21 Weights ••• 21 Reproduction. 24 Feeding habits. 26 Fish . 33 Euphausiids. 40 Cepha 1opods. 41 Age and growth. 41 Parasites 45 DISCUSSION 50 Catches 50 Lengths 52 Weights 53 Reproduction. 54 Feeding habits. 55 i v Engraul is mo rd ax 59 Merluccius ~uctus 60 Euphaus i ids. 61 Cephalopods. 65 Age and growth. 67 LITERATURE CITED 7 1 APPENDIX . 77 v LIST OF TABLES Table Page 1. Allometric growth relationships for six linear measurements on 115 blue sharks. 22 2. Prey items from 121 blue sharks collected between 1974 and 1977. Listed is the percent number (% N), percent volume (% V), percent frequency of occurrence(% FO), and index of relative importance (IRI) for each prey item. The prey are listed in decreasing order of importance, as determined by the IRI' s . 30 3. Prey items collected from 43 blue sharks in 1976. Listed is the percent number (% N), percent volume (% V), percent frequency of occurrence (% FO), and index of relative importance (IRI) for each prey item. The prey are 1 is ted in decreasing order of importance determined by the I RI. 35 4. Prey items from 58 blue sharks collected in 1977. Listed is the percent number (% N), percent val ume (% V), percent frequency of occurrence (% FO), and index of relative importance (IRI) for each prey item. Prey are listed in de- creasing order of importance as determined by the I RI. 37 vi 5. Mean total length measurements for blue sharks with assigned vertebral ring counts. Displayed are the sample sizes, one standard deviation, and 95% confidence intervals around the mean total lengths for females, males, and the total . 44 vi i LIST OF FIGURES Figure Page 1. Collection area for blue sharks in Nonterey Bay, California . 9 2. External measurements recorded for 120 blue sharks captured in Monterey Bay, California . 11 3. Example of measurements recorded for each blue shark centrum. • . 15 4. Number of blue sharks caught per hour for weekly intervals and the number of hours fished (effort) for 1976 and 1977. • . 19 5. Frequency histograms for total lengths of blue sharks caught in 1976, 1977, and all years combined ... 20 6. Body weight-total length relationship for 134 blue sharks collected in Monterey Bay. 23 7. Liver weight-body weight relationship for 106 female and 19 male blue sharks collected in Monterey Bay ... 25 8. Relation of cumulative prey items to randomly pooled numbers of blue sharks sampled in: (a) 1976, (b) 1977, and (c) all years combined 27 9. Feeding states of 121 blue sharks caught between 0700 and 1300 hours, from all years combined .. 29 vii i 10. Index of relative importance graph for the more important prey items of 121 blue sharks, from all years combined ... 32 11. Comparison of the major prey categories with regard to percent number (% N), percent volume (% V), percent frequency of occurrence(% FO), and index of relative importance (IRI), in the years sampled ..... 34 12. Index of relative importance graph for the more important prey items of 34 blue sharks collected in 1976 . • . 36 13. Index of relative importance graph for the more important prey items of 58 blue sharks collected in 1977 . 38 14. Ring radii measurements for blue sharks. 43 15. Growth curves for 16 rna le and 82 female b1 ue sharks caught in Monterey Bay .... • • 4 6 16. Comparison of growth curves from present study and that of Stevens (1975). ........• 4 7 17. Comparison of the total 1 ength histograms with lengths at a determined age for 98 blue sharks. • • . • • 48 18. Locations of observed surface swarms of euphausiids. 64 ix L ACKNOWLEDGMENTS I am grateful to many persons who contributed, in many ways, to the successful completion of this project. In par­ ticular, many helpful friends at Moss Landing Marine Labora­ tories have donated their valuable time and suggestions. Dr. G. Victor Morejohn, my major professor, provided guidance and financial support. Dr. Gregor H. Caill iet served as my advisor and gave generously of his time and support. Dr. Robert Has sur also served on my committee and helped in editing the manuscript. I extend my thanks to Roger Helm, Sara Tanner, Kon Karpov, Jim Heberle, Jerry Kashiwada, Bob Cayce, Kon Cayce, and Robert Yoklavich, to name only a few who have aided in my field collections. Lynne 0. Krasnow was a constant source of help, information, and 1 aughs throughout the research. Mary M. Yoklavich gave much of her time in data gathering, moral support, editing, and final typing of this thesis, and to her I am extremely indebted. Finally, I would like to thank my parents, who were instru- mental in my education and career and who assisted in the completion of this project. This investigation was funded by a grant from NOAA, Office of Sea Grant, Department of Commerce, #04-6-158- 44021. A portion of the i 11 ustrations were prepared by Mike Mallon. X INTRODUCTION The pelagic, marine ecosystem has become a current topic in scientific research, due to man's increasing interest and activity in the open ocean. Man's impact upon this system will be most apparent at the higher trophic levels. Pelagic sharks represent top carnivores in this complex and unex­ plored region of the ocean. They have also become a target in the development of elasmobranch fisheries (Holden, 1973; Ron s i v a 11 i , 1 97 8) . Un t i l r e c en t 1 y , the r o 1 e sharks p 1 ay in the pelagic environment and questions regarding their basic biology have not been explored. Information pertaining to the biology of these higher trophic level organisms may help to understand the intricate ecosystem to which they belong and the effects of man's activities on this system. The blue shark, Prionace glauca Linnaeus, is considered common in the warm temperate, tropical, and subtropical oceans of the world. Strasburg (1958) reported the blue shark to be the most abundant of the pelagic sharks in the central Pacific between 20°5 and 50°N latitude and 105°E and l85°W longitude. He found that the greatest abundance occurred north of 20°N latitude in the eastern part of the Pacific. Neave and Han­ avan (1950) found an extension of the distribution in the north Pacific to 57°N latitude in the Gulf of Alaska. Miller and Lea (1972) considered this species common in the eastern Pacific, from Chile to the Gulf of Alaska, but uncommon in the tropics. Blue sharks have been sighted from 0°N to 40°N latitude in the western Pacific (Suda, 1953). Bigelow and 1 L -----·---------- 2 Schroeder (1948) described the blue shark as the most plenti­ ful large oceanic shark in the Atlantic and Mediterranean Oceans. It is distributed from Africa to southern Norway in the eastern Atlantic and from Cuba to Newfoundland in the western Atlantic. In the Indian Ocean it is found from Africa to Australia, Indonesia and the Nicobar Islands between 17°N and 37°5 latitude (Gubanov and Grigor'yev, 1975). The migration of the blue shark into colder subpolar and temperate waters usually occurs during the hemispherical sum­ mer and early fall, when surface water temperatures increase. The studies of Neave and Hanavan (1960), in the Gulf of Alas­ ka, found blue sharks distributed only to 45°N during May and June, when the surface water temperature ranged from 5° C to 10° C. In August and September, however, they had increased their range to 57°N latitude, when the water warmed to approx­ • imately 15° C. They found that blue sharks were present in i water with temperatures ranging from 11 to 17° C.
Load more

Recommended publications
  • Fish Bulletin 152. Food Habits of Albacore, Bluefin Tuna, and Bonito in California Waters
    UC San Diego Fish Bulletin Title Fish Bulletin 152. Food Habits of Albacore, Bluefin Tuna, and Bonito In California Waters Permalink https://escholarship.org/uc/item/7t5868rd Authors Pinkas, Leo Oliphant, Malcolm S Iverson, Ingrid L.K. Publication Date 1970-06-01 eScholarship.org Powered by the California Digital Library University of California STATE OF CALIFORNIA THE RESOURCES AGENCY DEPARTMENT OF FISH AND GAME FISH BULLETIN 152 Food Habits of Albacore, Bluefin Tuna, and Bonito In California Waters By Leo Pinkas , Malcolm S. Oliphant, and Ingrid L. K. Iverson 1971 1 2 ABSTRACT The authors investigated food habits of albacore, Thunnus alalunga, bluefin tuna, Thunnus thynnus, and bonito, Sarda chiliensis, in the eastern North Pacific Ocean during 1968 and 1969. While most stomach samples came from fish caught commercially off southern California and Baja California, some came from fish taken in central Califor- nia, Oregon, and Washington waters. Standard procedures included enumeration of food items, volumetric analysis, and measure of frequency of occur- rence. The authors identified the majority of forage organisms to the specific level through usual taxonomic methods for whole animals. Identification of partially digested animals was accomplished through the use of otoliths for fish, beaks for cephalopods, and the exoskeleton for invertebrates. A pictorial guide to beaks of certain eastern Pacific cephalopods was prepared and proved helpful in identifying stomach contents. This guide is presented in this publication. The study indicates the prominent forage for bluefin tuna, bonito, and albacore in California waters is the northern anchovy, Engraulis mordax. 3 ACKNOWLEDGMENTS The Food Habits Study of Organisms of the California Current System, (Project 6–7-R), was an investigation estab- lished under contract between the U.S.
    [Show full text]
  • Defensive Behaviors of Deep-Sea Squids: Ink Release, Body Patterning, and Arm Autotomy
    Defensive Behaviors of Deep-sea Squids: Ink Release, Body Patterning, and Arm Autotomy by Stephanie Lynn Bush A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Integrative Biology in the Graduate Division of the University of California, Berkeley Committee in Charge: Professor Roy L. Caldwell, Chair Professor David R. Lindberg Professor George K. Roderick Dr. Bruce H. Robison Fall, 2009 Defensive Behaviors of Deep-sea Squids: Ink Release, Body Patterning, and Arm Autotomy © 2009 by Stephanie Lynn Bush ABSTRACT Defensive Behaviors of Deep-sea Squids: Ink Release, Body Patterning, and Arm Autotomy by Stephanie Lynn Bush Doctor of Philosophy in Integrative Biology University of California, Berkeley Professor Roy L. Caldwell, Chair The deep sea is the largest habitat on Earth and holds the majority of its’ animal biomass. Due to the limitations of observing, capturing and studying these diverse and numerous organisms, little is known about them. The majority of deep-sea species are known only from net-caught specimens, therefore behavioral ecology and functional morphology were assumed. The advent of human operated vehicles (HOVs) and remotely operated vehicles (ROVs) have allowed scientists to make one-of-a-kind observations and test hypotheses about deep-sea organismal biology. Cephalopods are large, soft-bodied molluscs whose defenses center on crypsis. Individuals can rapidly change coloration (for background matching, mimicry, and disruptive coloration), skin texture, body postures, locomotion, and release ink to avoid recognition as prey or escape when camouflage fails. Squids, octopuses, and cuttlefishes rely on these visual defenses in shallow-water environments, but deep-sea cephalopods were thought to perform only a limited number of these behaviors because of their extremely low light surroundings.
    [Show full text]
  • Giant Protistan Parasites on the Gills of Cephalopods (Mollusca)
    DISEASES OF AQUATIC ORGANISMS Vol. 3: 119-125. 1987 Published December 14 Dis. aquat. Org. Giant protistan parasites on the gills of cephalopods (Mollusca) Norman ~c~ean',F. G. ~ochberg~,George L. shinn3 ' Biology Department, San Diego State University, San Diego, California 92182-0057, USA Department of Invertebrate Zoology, Santa Barbara Museum of Natural History, 2559 Puesta Del Sol Road, Santa Barbara, California 93105. USA Division of Science, Northeast Missouri State University, Kirksville. Missouri 63501, USA ABSTRACT: Large Protista of unknown taxonomic affinities are described from 3 species of coleoid squids, and are reported from many other species of cephalopods. The white to yellow-orange, ovoid cyst-like parasites are partially embedded within small pockets on the surface of the gills, often in large numbers. Except for a holdfast region on one side of the large end, the surface of the parasite is elaborated into low triangular plates separated by grooves. The parasites are uninucleate; their cytoplasm bears lipid droplets and presumed paraglycogen granules. Trichocysts, present in a layer beneath the cytoplasmic surface, were found by transmission electron microscopy to be of the dino- flagellate type. Further studies are needed to clarify the taxonomic position of these protists. INTRODUCTION epoxy resin (see below). One specimen each of the coleoid squids Abralia trigonura and Histioteuthis dof- Cephalopods harbor a diversity of metazoan and leini were trawled near Oahu, Hawaii, in March, 1980. protozoan parasites (Hochberg 1983). In this study we Gill parasites from the former were fixed in formalin; used light and electron microscopy to characterize a those from the latter were fixed in osmium tetroxide.
    [Show full text]
  • Identification and Estimation of Size from the Beaks of 18 Species of Cephalopods from the Pacific Ocean
    17 NOAA Technical Report NMFS 17 Identification and Estimation of Size From the Beaks of 18 Species of Cephalopods From the Pacific Ocean Gary A. Wolff November 1984 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service NOAA TECHNICAL REPORTS NMFS The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fishery resources, to understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum use of the resources. NMFS is also charged with the development and implemen­ tation of policies for managing national fishing grounds, development and enforcement of domestic fisheries regulations, surveillance of foreign fishing off United States coastal waters, and the development and enforcement of international fishery agreements and policies. NMFS also assists the fishing industry through marketing service and economic analysis programs, and mortgage insurance and vessel construction subsidies. It collects, analyzes, and publishes statistics on various phases of the industry. The NOAA Technical Report NMFS series was established in 1983 to replace two subcategories of the Technical Reports series: "Special Scientific Report-Fisheries" and "Circular." The series contains the following types of reports: Scientific investigations that document long-term continuing programs of NMFS, intensive scientific reports on studies of restricted scope, papers on applied fishery problems, technical reports of general interest intended to aid conservation and management, reports that review in considerable detail and at a high technical level certain broad areas of research, and technical papers originating in economics studies and from management investigations.
    [Show full text]
  • The Natural Resources of Monterey Bay National Marine Sanctuary
    Marine Sanctuaries Conservation Series ONMS-13-05 The Natural Resources of Monterey Bay National Marine Sanctuary: A Focus on Federal Waters Final Report June 2013 U.S. Department of Commerce National Oceanic and Atmospheric Administration National Ocean Service Office of National Marine Sanctuaries June 2013 About the Marine Sanctuaries Conservation Series The National Oceanic and Atmospheric Administration’s National Ocean Service (NOS) administers the Office of National Marine Sanctuaries (ONMS). Its mission is to identify, designate, protect and manage the ecological, recreational, research, educational, historical, and aesthetic resources and qualities of nationally significant coastal and marine areas. The existing marine sanctuaries differ widely in their natural and historical resources and include nearshore and open ocean areas ranging in size from less than one to over 5,000 square miles. Protected habitats include rocky coasts, kelp forests, coral reefs, sea grass beds, estuarine habitats, hard and soft bottom habitats, segments of whale migration routes, and shipwrecks. Because of considerable differences in settings, resources, and threats, each marine sanctuary has a tailored management plan. Conservation, education, research, monitoring and enforcement programs vary accordingly. The integration of these programs is fundamental to marine protected area management. The Marine Sanctuaries Conservation Series reflects and supports this integration by providing a forum for publication and discussion of the complex issues currently facing the sanctuary system. Topics of published reports vary substantially and may include descriptions of educational programs, discussions on resource management issues, and results of scientific research and monitoring projects. The series facilitates integration of natural sciences, socioeconomic and cultural sciences, education, and policy development to accomplish the diverse needs of NOAA’s resource protection mandate.
    [Show full text]
  • Diet and Foraging Strategies of a Deep-Sea Predator, the Northern Elephant Seal
    UNIVERSITY OF CALIFORNIA SANTA CRUZ ILLUMINATING THE TWILIGHT ZONE: DIET AND FORAGING STRATEGIES OF A DEEP-SEA PREDATOR, THE NORTHERN ELEPHANT SEAL A dissertation submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in ECOLOGY AND EVOLUTIONARY BIOLOGY by Chandra Goetsch December 2018 The Dissertation of Chandra Goetsch is approved: _________________________________ Professor Daniel P. Costa, Chair _________________________________ Professor Pete Raimondi _________________________________ Dr. Elliott L. Hazen _________________________________ Professor Raphael M. Kudela _________________________________ Lori Kletzer Vice Provost and Dean of Graduate Studies Copyright © by Chandra Goetsch 2018 TABLE OF CONTENTS LIST OF TABLES ...................................................................................... vii LIST OF FIGURES...................................................................................... ix ABSTRACT .............................................................................................. xiv ACKNOWLEDGEMENTS ......................................................................... xvii DEDICATION ......................................................................................... xxvi INTRODUCTION ..........................................................................................1 Broad Context ......................................................................................................... 1 Dissertation Summary ...........................................................................................
    [Show full text]
  • Feeding Habits and Trophic Level of the Smooth Hammerhead Shark
    Journal of the Marine Biological Association of the United Kingdom, 2019, 99(3), 673–680. # Marine Biological Association of the United Kingdom, 2018 doi:10.1017/S0025315418000474 Feeding habits and trophic level of the smooth hammerhead shark, Sphyrna zygaena (Carcharhiniformes: Sphyrnidae), off Ecuador colombo estupin~a’ n-montan~o1,2, luis ceden~o-figueroa3, jose’ f. estupin~a’ n-ortiz1, felipe galva’ n-magan~a4, alejandro sandoval-london~o1,5, david castan~eda-suarez6 and carlos j. polo-silva6 1Fundacio´n Alium Pacific, Carrera 26 No. 5C–13, Cali, Colombia, 2Servicio Nacional de Aprendizaje, Centro Agroindustrial y Pesquero de la Costa Pacı´fica, La Chiricana km 21, Tumaco, Colombia, 3Facultad Ciencias del Mar, Universidad Laica “Eloy Alfaro” de Manabı´, Manta, Ecuador, 4Instituto Polite´cnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Av. IPN s/n, La Paz, Baja California Sur, C.P. 23096, Mexico, 5Corporacio´n Acade´mica Ambiental, Universidad de Antioquia, Calle 70 No. 52-21, Medellı´n, Colombia, 6Facultad de Ciencias Naturales e Ingenierı´a, Programa de Biologı´a Marina, Universidad de Bogota´ Jorge Tadeo Lozano, Santa Marta, Colombia As apex predators, sharks are known to play an important role in marine food webs. Detailed information on their diet and trophic level is however needed to make clear inferences about their role in the ecosystem. A total of 335 stomachs of smooth hammerhead sharks, Sphyrna zygaena, were obtained from commercial fishing vessels operating in the Ecuadorian Pacific between January and December 2004. A total of 53 prey items were found in the stomachs. According to the Index of Relative Importance (%IRI), cephalopods were the main prey (Dosidicus gigas, Sthenoteuthis oualaniensis, Ancistrocheirus lesueurii and Lolliguncula [Loliolopsis] diomedeae).
    [Show full text]
  • Ecología De Los Peces Amazónicos En El Ecuador, Pp
    Citación sugerida: Para todo el documento: Jiménez-Prado, P y J. Valdiviezo-Rivera (Eds.). 2021. Biodiversidad de peces en el Ecuador. Serie Especial de Ictiología Ecuatoriana I. Red Ecuatoriana de ictiología, Pontificia Universidad Católica del Ecuador Sede Esmeraldas, Universidad Tecnológica Indoamérica, Instituto Nacional de Biodiversidad. 166 pp. Para sus capítulos: Puertas, C. 2021. Ecología de los peces amazónicos en el Ecuador, pp. 10 - 21. En Jiménez-Prado, P y J. Valdiviezo- Rivera (ed.). 2021. Biodiversidad de peces en el Ecuador. Serie Especial de Ictiología Ecuatoriana I. Red Ecuatoriana de ictiología, Pontificia Universidad Católica del Ecuador Sede Esmeraldas, Universidad Tecnológica Indoamérica, Instituto Nacional de Biodiversidad. 166 pp. ISBN: 9 7 8 - 9 9 4 2 - 4 0 - 1 5 4 - 0 D.R. © Red Ecuatoriana de Ictiología Responsabilidad: El material aquí presentado, así como las opiniones expresadas, no representan necesariamente el juicio o las políticas de las instituciones participantes. Todo lo expresado es de la entera responsabilidad de los autores. Los escritos y la información presentada han sido editadas con aprobación previa de sus autores. Cuerpo editorial para la revisión ciega por pares Aguirre Windsor. Department of Biological Sciences, DePaul University, Chicago. Buenaño Martha. Ictióloga independiente. Burgos Ricardo. Departamento de Ciencias de la Tierra, Universidad Estatal amazónica. Carrillo-Moreno Carolina. Investigadora asociada del INABIO. Carvache- Wilan Evelyn. Ictióloga independiente. Escobar-Camacho Daniel. Laboratorio de Ecología Acuática, Instituto Biósfera, Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Quito, Ecuador Moreno Cristhian. Ictiólogo independiente. Nugra Fredy. Laboratorio de Limnología de la Universidad del Azuay, Cuenca, Ecuador. Revelo-Ramírez Willian. Unidad de Recursos Demersales Bentónicos de Agua Dulce y Embalses, Instituto Público de Investigación de Acuicultura y Pesca.
    [Show full text]
  • Recent Cephalopoda Primary Types
    Ver. 2 March 2017 RECENT CEPHALOPOD PRIMARY TYPE SPECIMENS: A SEARCHING TOOL Compiled by Michael J. Sweeney Introduction. This document was first initiated for my personal use as a means to easily find data associated with the ever growing number of Recent cephalopod primary types. (Secondary types (paratypes, etc) are not included due to the large number of specimens involved.) With the excellent resources of the National Museum of Natural History, Smithsonian Institution and the help of many colleagues, it grew in size and became a resource to share with others. Along the way, several papers were published that addressed some of the problems that were impeding research in cephalopod taxonomy. A common theme in each paper was the need to locate and examine types when publishing taxonomic descriptions; see Voss (1977:575), Okutani (2005:46), Norman and Hochberg (2005b:147). These publications gave me the impetus to revive the project and make it readily available. I would like to thank the many individuals who assisted me with their time and knowledge, especially Clyde Roper, Mike Vecchione, Eric Hochberg and Mandy Reid. Purpose. This document should be used as an aid for finding the location of types, type names, data, and their publication citation. It is not to be used as an authority in itself or to be cited as such. The lists below will change over time as more research is published and ambiguous names are resolved. It is only a search aid and data from this document should be independently verified prior to publication. My hope is that this document will make research easier and faster for the user.
    [Show full text]
  • Relationships of the Blue Shark, Przonace Glauca, and Its Prey Species Near Santa Catalina Island, California'
    RELATIONSHIPS OF THE BLUE SHARK, PRZONACE GLAUCA, AND ITS PREY SPECIES NEAR SANTA CATALINA ISLAND, CALIFORNIA' ABSTRACT Small fishes and cephalopds associated with both pelagic and inshore habitats composed the major prey for the blue shark, Prionace glauca, near Santa Catalina Island, Calif. The northern anchovy, Engraulis mordm, was the predominant prey for sharks in the immediate study area while at least 13 species of pelagic cephalopdsconstituted major prey for sharks in more distant oceanic waters. Inshore species taken by sharks included pipefish, Syngnathus californiensis; jack mackerel, Trachurus sym- metricus; and blacksmith, Chromispunctipinnis. In addition, sharks moved inshore to feed on winter spawning schools of market squid, Loligo opalescens. Digestive rate studies and telemetric monitoring of activity patterns indicate that sharks forage in waters near the surface from around midnight through dawn. Die1 activities of prey species were examined and show that most prey dispersed in the upper water column at night and refuged during the day either by schooling (anchovies and jack mackerel) or by retreating to deeper waters (pelagic cephalopods). Field observations of shark feeding behavior indicate that predatory modes vary in response to prey behavior. The blue shark,Prionace glauca (Carcharhinidae) of mammalian tissue in the diet of blue sharks is (Figure 11, is a pelagic carnivore cosmopolitan in rare (Strasburg 1958; Stevens 19731, and such tropical and warm temperate seas. Because of its feeding is most likely directed to dead mammals or pelagic habits, the majority of ecological studies those in poor health. Aidsea disasters have re- on this species have been predicated on data from sulted in attacks on humans by blue sharks (see sharks captured by sport and commercial Schultz and Malin 1963; Fitch3) but these cases fisheries.
    [Show full text]
  • Diversity and Ecological Roles of Noncommercial Fishes in California Mar1 N E Habitats
    HORN: DIVERSITY AND ECOLOGICAL ROLES OF NONCOMMERCIAL FISHES CalCOFI Rep., Vol. XXI, 1980 DIVERSITY AND ECOLOGICAL ROLES OF NONCOMMERCIAL FISHES IN CALIFORNIA MAR1 N E HABITATS MICHAEL H. HORN Department of Biology California State University Fullerton. CA 92635 ABSTRACT habitat ocupado por 10s peces de importancia economica. The marine fish fauna of California is highly diverse Las especies que no son comerciales pueden funcionar and consists of about 550 species of varied origin and como 1) predadores o presas, asi son eslabones troficos complex distribution. Species richness is greatest in directos en la cadena alimenticia de las especies comer- southern California and gradually declines northward in a ciales; 2) competidores de las especies explotadas; 6 3) pattern that is significantly correlated with increasing peces que, por su posicion ecologica, afectan la estructura latitude and decreasing minimum surface temperature. de la comunidad e influyen indirectamente en las pobla- Greater activity with regard to species range termina- ciones de importancia economica. tions occurs in southern California than in central and Se describe brevemente las comunidades de peces y northern California and is consistent with the higher ciertas especies de importancia ecologica para cada uno species richness in southern California waters. de 10s siete habitats mas importantes en las aguas Less than 3% of the species of this diverse fauna con- oceanicas de California: 1) zona profunda mesopelagica, tributes significantly to the California commercial fish 2) zona epipelagica, 3) region demersal costera, 4) lechos catch. Many noncommercial species, therefore, perform de algas marinadarrecifes sublitorales, 5) zona de entre essential roles in the habitats occupied by economically mareas rocosa, 6) puertos, y 7) bahias y estuarios.
    [Show full text]
  • Apristurus Brunneus and Parmaturus Xaniurus) in Central California, USA
    California State University, Monterey Bay Digital Commons @ CSUMB Capstone Projects and Master's Theses Capstone Projects and Master's Theses Spring 2021 Evaluating the Trophic Habits and Dietary Overlap of Two Deep- Sea Catsharks (Apristurus brunneus and Parmaturus xaniurus) in Central California, USA Matthew Jew Follow this and additional works at: https://digitalcommons.csumb.edu/caps_thes_all This Master's Thesis (Open Access) is brought to you for free and open access by the Capstone Projects and Master's Theses at Digital Commons @ CSUMB. It has been accepted for inclusion in Capstone Projects and Master's Theses by an authorized administrator of Digital Commons @ CSUMB. For more information, please contact [email protected]. Evaluating the trophic habits and dietary overlap of two deep-sea catsharks (Apristurus brunneus and Parmaturus xaniurus) in central California, USA _______________ A Thesis Presented to the Faculty of Moss Landing Marine Laboratories California State University Monterey Bay _______________ In Partial Fulfillment of the Requirements for the Degree Master of Science in Marine Science _______________ by Matthew Jew Spring 2021 CALIFORNIA STATE UNIVERSITY MONTEREY BAY The Undersigned Faculty Committee Approves the Thesis of Matthew Jew: EVALUATING THE TROPHIC HABITS AND DIETARY OVERLAP OF TWO DEEP- SEA CATSHARKS (APRISTURUS BRUNNEUS AND PARMATURUS XANIURUS) IN CENTRAL CALIFORNIA, USA _____________________________________________ Scott L. Hamilton, Chair Moss Landing Marine Laboratories _____________________________________________
    [Show full text]