DOCSLIB.ORG

Sawsharks (Pristiophorus Spp.)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sawsharks (Pristiophorus Spp.) I & I NSW WILD FISHERIES RESEARCH PROGRAM Sawsharks (Pristiophorus spp.) EXPLOITATION STATUS UNDEFINED Little information is available to assess stock status. Biological information from local populations should be collected. SCIENTIFIC NAME STANDARD NAME COMMENT Pristiophorus cirratus common sawshark The majority of NSW catch. Pristiophorus nudipinnis southern sawshark Occurs from southern NSW to central SA. Pristiophorus cirratus Image © Bernard Yau Background Biological data collected off NSW for the Sawsharks (family Pristiophoridae) are relatively common sawshark showed that males matured small sharks (< 150 cm total length (TL)) at about 80 cm TL while the largest measured characterised by a narrow blade-shaped snout was 112 cm TL weighing about 2.7 kg. Females with numerous slender, sharp spines along its matured at about 90 cm and grew to a margins. Sawsharks should not be confused maximum of about 125 cm (~3.5 kg). with the large tropical sawfishes which also Sawsharks are viviparous (trophodermic – the possess a long saw-like snout; sawfishes live in developing young receive some nutrients shallow seas, estuaries and rivers, and can grow through the mother’s uterine epithelium) to seven metres in length. and give birth to fully developed young after Of the three Australian sawshark species, two a gestation period of at least 12 months. are distributed around southern Australia, Common sawsharks generally give birth to and the third is found in deepwater off about 11 pups (range 6 to 22) which vary in size northern Queensland. The common sawshark between 35 and 38 cm TL. Southern sawsharks (Pristiophorus cirratus) is the main species caught also average about 11 pups (range 7 to 14) but in NSW waters. It is found mainly in outer they are smaller (30 to 35 cm TL). shelf and upper slope depths (40-630 m), and Sawsharks are a minor component of the its known distribution is from northern NSW Commonwealth managed Southern Shark (Coffs Harbour) to Jurien Bay (WA), including Fishery, where their status is considered to be Tasmania. The southern sawshark P. nudipinnis ‘uncertain’ - landings by Commonwealth fishers occurs from central NSW to Eyre (WA) in the in 2008 were about 250 t. Great Australian Bight, in depths to at least 110 m. The small NSW catch is taken almost totally by trawling. Sawsharks are only occasionally taken by recreational fishers. STATUS OF FISHERIES RESOURCES IN NSW, 2008/09 SawshaRKS | P 267 WILD FISHERIES RESEARCH PROGRAM Additional Notes Landings by Commercial Fishery of Sawsharks • P. cirratus is the main species taken off NSW Ocean Prawn Trawl (Key Secondary Species) - annual landings have fluctuated between Fish Trawl (Key Secondary Species) 10 and 30 t in recent years. 35 • This group should not be confused with the 30 sawfish family (Pristidae). 25 • The Commonwealth has imposed a total allowable catch (312 t in 2008) on sawsharks 20 Landings (t) taken in the Southern Shark Fishery. 15 • Sexed length frequency data are available 10 from Kapala (Fisheries Research Vessel) data, 5 but there are no useful size composition data 0 from the commercial fishery. 97/98 99/00 01/02 03/04 05/06 07/08 Financial Year Reported landings of sawsharks by NSW commercial Catch fisheries from 1997/98. Fisheries which contribute less than 2.5% of the landings are excluded for clarity and Recreational Catch of Sawsharks privacy. The annual recreational harvest of sawsharks in NSW is likely to be less than one tonne. Catch Per Unit Effort Information of Sawsharks Historical Landings of Sawsharks Harvested by Fish Trawling in NSW 40 1.0 0.8 30 0.6 20 Landings (t) 0.4 Relative Catch Rate 10 0.2 0 0.0 90/91 92/93 94/95 96/97 98/99 00/01 02/03 04/05 06/07 08/09 93/94 98/99 03/04 08/09 Financial Year Financial Year Commercial landings (including available historical Catch rates of sawsharks harvested using fish trawling records) of sawsharks for NSW from 1990/91 to 2008/09 for NSW. Two indicators are provided: (1) median catch for all fishing methods. rate (lower solid line); and (2) 90th percentile of the catch rate (upper dashed line). Note that catch rates are not a robust indicator of abundance in many cases. Caution should be applied when interpreting these results. P 268 | SawshaRKS STATUS OF FISHERIES RESOURCES IN NSW, 2008/09 Length Frequency of Sawsharks Wilson, D., R. Curtotti, G. Begg and K. Phillips, Eds. 0.12 1992/93−1996/97 (2009). Fishery Status Reports 2008: status of fish n = 2362 stocks and fisheries managed by the Australian 0.10 Government. Canberra, Bureau of Rural Sciences & Australian Bureau of Agricultural and Resource 0.08 Economics. 0.06 Yearsley, G.K., P.R. Last and R.D. Ward (1999). Australian Proportion 0.04 Seafood Handbook. Hobart, CSIRO Marine Research. 0.02 Please visit the CSIRO website, 0.00 http://www.marine.csiro.au/caab/ and search for 20 40 60 80 100 120 the species code (CAAB) 37 023003, 37 023002 and TL (cm) 37 023001, common name or scientific name to find The length distribution of sawsharks caught during trawl further information. surveys by the Fisheries Research Vessel Kapala was comprised mainly of sharks between 40 and 120 cm total length (TL - including the length of the ‘saw’). There is no minimum legal length for sawsharks in NSW. Further Reading Gomon, M.F., J.C.M. Glover and R.H. Kuiter (1994). The Fishes of Australia’s South Coast. Adelaide, State Print. Hutchins, B. and R. Swainston (1999). Sea Fishes of Southern Australia - Complete Field Guide for Anglers and Divers. Smithfield, NSW, Gary Allen Pty Ltd. Last, P.R. and J.D. Stevens (1994). Sharks and Rays of Australia. Melbourne, CSIRO. Punt, A.E., T.I. Walker and A.S. Gason (2004). Initial assessments of sawshark (Pristiophorus cirratus and P. nudipinnis) and elephant fish Callorhinchus( milii). In: G. N. Tuck and A. D. M. Smith (eds), Stock assessment for South East and Southern Shark Fishery Species FRDC Project No 2001/005. Hobart, Tasmania, CSIRO Marine Research: 335-369 pp. Walker, T.I. and R.J. Hudson (2005). Sawshark and elephant fish assessment and by-catch evaluation in the Southern Shark Fishery. Final Report, FRDC project 1999/103. Victoria, Primary Industries Research. © State of New South Wales through Industry and Investment NSW 2010. You may copy, distribute and otherwise freely deal with this publication for any purpose, provided that you attribute Industry and Investment NSW as the owner. Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (April 2010). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of Industry and Investment NSW or the user’s independent adviser. SawshaRKS | P 269 WILD FISHERIES RESEARCH PROGRAM P 270 | SawshaRKS.
Load more

Recommended publications
  • Sharks for the Aquarium and Considerations for Their Selection1 Alexis L
    FA179 Sharks for the Aquarium and Considerations for Their Selection1 Alexis L. Morris, Elisa J. Livengood, and Frank A. Chapman2 Introduction The Lore of the Shark Sharks are magnificent animals and an exciting group Though it has been some 35 years since the shark in Steven of fishes. As a group, sharks, rays, and skates belong to Spielberg’s Jaws bit into its first unsuspecting ocean swim- the biological taxonomic class called Chondrichthyes, or mer and despite the fact that the risk of shark-bite is very cartilaginous fishes (elasmobranchs). The entire supporting small, fear of sharks still makes some people afraid to swim structure of these fish is composed primarily of cartilage in the ocean. (The chance of being struck by lightning is rather than bone. There are some 400 described species of greater than the chance of shark attack.) The most en- sharks, which come in all different sizes from the 40-foot- grained shark image that comes to a person’s mind is a giant long whale shark (Rhincodon typus) to the 2-foot-long conical snout lined with multiple rows of teeth efficient at marble catshark (Atelomycterus macleayi). tearing, chomping, or crushing prey, and those lifeless and staring eyes. The very adaptations that make sharks such Although sharks have been kept in public aquariums successful predators also make some people unnecessarily since the 1860s, advances in marine aquarium systems frightened of them. This is unfortunate, since sharks are technology and increased understanding of shark biology interesting creatures and much more than ill-perceived and husbandry now allow hobbyists to maintain and enjoy mindless eating machines.
    [Show full text]
  • NPOA Sharks Booklet.Indd
    National Plan of Action for the Conservation and Management of Sharks (NPOA-Sharks) November 2013 South Africa Department of Agriculture, Forestry and Fisheries Private Bag X2, Rogge Bay, 8012 Tel: 021 402 3911 Fax: +27 21 402 3364 www.daff.gov.za Design and Layout: FNP Communications and Gerald van Tonder Photographs courtesy of: Department of Agriculture, Forestry and Fisheries (DAFF), Craig Smith, Charlene da Silva, Rob Tarr Foreword South Africa’s Exclusive Economic Zone is endowed with a rich variety of marine living South Africa is signatory to the Code of Conduct for Responsible Fisheries – voluntarily agreed to by members of the United Nations Food and Agriculture Organisation (FAO) – and, as such, is committed to the development and implementation of National Plans of Action (NPOAs) as adopted by the twenty-third session of the FAO Committee on Fisheries in February 1999 and endorsed by the FAO Council in June 1999. Seabirds – aimed at reducing incidental catch and promoting the conservation of seabirds Fisheries and now regularly conducts Ecological Risk Assessments for all the commercial practices. Acknowledging the importance of maintaining a healthy marine ecosystem and the possibility of major detrimental effects due to the disappearance of large predators, South from the list of harvestable species. In accordance with international recommendations, South Africa subsequently banned the landing of a number of susceptible shark species, including oceanic whitetip, silky, thresher and hammerhead sharks. improves monitoring efforts for foreign vessels discharging shark products in its ports. To ensure long-term sustainability of valuable, but biologically limited, shark resources The NPOA-Sharks presented here formalises and streamlines ongoing efforts to improve conservation and management of sharks caught in South African waters.
    [Show full text]
  • Florida's Fintastic Sharks and Rays Lesson and Activity Packet
    Florida's Fintastic Sharks and Rays An at-home lesson for grades 3-5 Produced by: This educational workbook was produced through the support of the Indian River Lagoon National Estuary Program. 1 What are sharks and rays? Believe it or not, they’re a type of fish! When you think “fish,” you probably picture a trout or tuna, but fishes come in all shapes and sizes. All fishes share the following key characteristics that classify them into this group: Fishes have the simplest of vertebrate hearts with only two chambers- one atrium and one ventricle. The spine in a fish runs down the middle of its back just like ours, making fish vertebrates. All fishes have skeletons, but not all fish skeletons are made out of bones. Some fishes have skeletons made out of cartilage, just like your nose and ears. Fishes are cold-blooded. Cold-blooded animals use their environment to warm up or cool down. Fins help fish swim. Fins come in pairs, like pectoral and pelvic fins or are singular, like caudal or anal fins. Later in this packet, we will look at the different types of fins that fishes have and some of the unique ways they are used. 2 Placoid Ctenoid Ganoid Cycloid Hard protective scales cover the skin of many fish species. Scales can act as “fingerprints” to help identify some fish species. There are several different scale types found in bony fishes, including cycloid (round), ganoid (rectangular or diamond), and ctenoid (scalloped). Cartilaginous fishes have dermal denticles (Placoid) that resemble tiny teeth on their skin.
    [Show full text]
  • We've Just Discovered Two New Shark Species
    19/03/2020 We've just discovered two new shark species Academic rigour, journalistic flair One of the newly discovered sixgilled sawshark species (Pliotrema kajae). Simon Weigmann, Author provided We’ve just discovered two new shark species March 18, 2020 6.05pm GMT Finding a species that’s entirely new to science is always exciting, and so we were Authors delighted to be a part of the discovery of two new sixgill sawsharks (called Pliotrema kajae and Pliotrema annae) off the coast of East Africa. We know very little about sawsharks. Until now, only one sixgill species (Pliotrema Per Berggren warreni) was recognised. But we know sawsharks are carnivores, living on a diet of Marine MEGAfauna Lab, Newcastle fish, crustaceans and squid. They use their serrated snouts to kill their prey and, with University quick side-to-side slashes, break them up into bite-sized chunks. Andrew Temple Postdoctoral Research Associate in Marine Biology, Newcastle University https://theconversation.com/weve-just-discovered-two-new-shark-species-134067 1/7 19/03/2020 We've just discovered two new shark species The serrated snout of a sixgill sawshark (Pliotrema annae). Ellen Barrowclift-Mahon/Marine MEGAfauna Lab/Newcastle University., Author provided Sawsharks look similar to sawfish (which are actually rays), but they are much smaller. Sawsharks grow to around 1.5 metres in length, compared to 7 metres for a sawfish and they also have barbels (fish “whiskers”), which sawfish lack. Sawsharks have gills on the side of their heads, whereas sawfish have them on the underside of their bodies. https://theconversation.com/weve-just-discovered-two-new-shark-species-134067 2/7 19/03/2020 We've just discovered two new shark species A sixgill sawshark (Pliotrema annae) turned on its side, showing gills and barbels.
    [Show full text]
  • The Cast of SHARKS
    The Cast of SHARKS EDUCATOR’S GUIDE 1 Introduction The Cast of SHARKS describes each species you will encounter in SHARKS, presenting some of its most important characteristics, such as average size, behavior (social, territorial, schooling, aggressive, gentle, etc.), fins, coloration, feeding habits, habitat, reproduction, potential danger to humans, endangered species. The Cast of SHARKS SAND TIGER SHARK ..........................................................................................................3 SILVERTIP SHARK ..............................................................................................................5 GIANT PACIFIC MANTA RAY..............................................................................................7 LARGE TOOTH SAWFISH ..................................................................................................9 GREAT WHITE SHARK ......................................................................................................11 SCALLOPED HAMMERHEAD..............................................................................................13 GREAT HAMMERHEAD SHARK ........................................................................................15 GRAY REEF SHARK ............................................................................................................16 WHALE SHARK ..................................................................................................................18 THE THEME SONG ............................................................................................................20
    [Show full text]
  • Identifying Sharks and Rays
    NSW DPI Identifying sharks and rays A guide for NSW commercial fishers Important If a shark or ray cannot be confidently identified using this guide, it is recommended that either digital images are obtained or the specimen is preserved. Please contact NSW DPI research staff for assistance: phone 1300 550 474 or email [email protected] Contents Introduction 4 How to use this guide 5 Glossary 6-7 Key 1 Whaler sharks and other sharks of similar appearance 8-9 to whalers – upper precaudal pit present Key 2 Sharks of similar appearance to whaler sharks – no 10 precaudal pit Key 3 Mackerel (great white and mako), hammerhead and 11 thresher sharks Key 4 Wobbegongs and some other patterned 12 bottom-dwelling sharks Key 5 Sawsharks and other long-snouted sharks and rays 13 2 Sandbar shark 14 Great white shark 42 Bignose shark 15 Porbeagle 43 Dusky whaler 16 Shortfin mako 44 Silky shark 17 Longfin mako 45 Oceanic whitetip shark 18 Thresher shark 46 Tiger shark 19 Pelagic thresher 47 Common blacktip shark 20 Bigeye thresher 48 Spinner shark 21 Great hammerhead 49 Blue shark 22 Scalloped hammerhead 50 Sliteye shark 23 Smooth hammerhead 51 Bull shark 24 Eastern angelshark 52 Bronze whaler 25 Australian angelshark 53 Weasel shark 26 Banded wobbegong 54 Lemon shark 27 Ornate wobbegong 55 Grey nurse shark 28 Spotted wobbegong 56 Sandtiger (Herbst’s nurse) shark 29 Draughtboard shark 57 Bluntnose sixgill shark 30 Saddled swellshark 58 Bigeye sixgill shark 31 Whitefin swellshark 59 Broadnose shark 32 Port Jackson shark 60 Sharpnose sevengill
    [Show full text]
  • SHARK FACTS There Are 510 Species of Sharks
    1 SHARK FACTS There are 510 species of sharks. Let’s learn more about a few of them. Common Six-gilled Thresher Shark Shark • Known for its 10 foot tail • Can grow up to 16 feet long • Stuns and herds fish with its long tail • Has six pairs of gills instead of the average of five • Warm blooded • Has one dorsal fin at the back of its body • Feeds on squid and schooling fish • Also known as cow shark or mud shark • Prefers to stay towards the top of deep bodies • Deep water shark of water Shortfin Great Mako Hammerhead Shark Shark • Bluish gray on top part of body and white on • Eyes are at opposite sides of its rectangular the belly shaped head • Has extremely sharp teeth, that stick out even when • Feeds on crustaceans, octopuses, rays and its mouth is shut small sharks • Feeds on sharks, swordfish and tuna • Usually found around tropical reefs • Jumps high in the air to escape fishing hooks • Can give birth to over 40 pups in one litter • Fastest of all the sharks as it can swim over 30 mph • Has a heigtened sense of electro-reception 2 SHARK FACTS Bull Nurse Shark Shark • Can grow up to 11 feet long and over 200 pounds • Has long, fleshy appendages called barbels that hang below its snout • Gray to brown in color with a white belly • Feeds on crab, lobster, urchins and fish • Feeds on fish, dolphins, sea turtles and other sharks • Usually found near rocky reefs, mudflats • Found in fresh and salt water and sandbars • Aggressive species • Enjoys laying on the ocean floor • Nocturnal animal Great Epaulette White Shark Shark • Can grow
    [Show full text]
  • Uterine Fluid Composition of the Dwarf Ornate Wobbegong Shark (Orectolobus Ornatus) During Gestation
    CSIRO PUBLISHING Marine and Freshwater Research, 2011, 62, 576–582 www.publish.csiro.au/journals/mfr Uterine fluid composition of the dwarf ornate wobbegong shark (Orectolobus ornatus) during gestation Megan T. EllisA,B and Nicholas M. OtwayA AIndustry and Investment NSW, Port Stephens Fisheries Institute, Taylors Beach, NSW 2316, Australia. BCorresponding author. Email: [email protected] Abstract. Low fecundity in chondrichthyans makes them extremely susceptible to fishing, so understanding the various reproductive strategies in this group is vital for management. Knowledge of the uterine fluid (UF) composition throughout gestation is fundamental to this understanding, yet is restricted to a few species. This study focussed on the UF composition of the wobbegong (Orectolobus ornatus), which inhabits coastal waters off eastern Australia. The UF was quantified throughout pregnancy. Fluids surrounding uterine eggs had a complex composition, with mean urea (98.48 mmol LÀ1), sodium (560.25 mmol LÀ1) and potassium (13.93 mmol LÀ1) concentrations significantly greater than those in seawater. A change in composition, from complex to simple, occurred after 3–4 months gestation. Major electrolyte concentrations then resembled seawater for the remainder of gestation, suggesting the flushing of the uteri with seawater and evidenced by fluctuating low levels of urea. The gestation period reflected the time for metabolism of yolk stores, osmotic and ionic adjustment, development of functioning immunological systems and prevention of external
    [Show full text]
  • 251 Part 640—Spiny Lobster Fishery of the Gulf Of
    Fishery Conservation and Management Pt. 640 of an application for an ILAP or an ap- Sevengill, Heptranchias perlo peal of NMFS's denial of an initial lim- Sixgill, Hexanchus griseus ited access permit for swordfish. Smalltail, Carcharhinus porosus (12) Falsify information submitted Whale, Rhincodon typus White, Carcharodon carcharias under § 635.46(b) in support of entry of imported swordfish. TABLE 2 OF APPENDIX A TO PART 635± (13) Exceed the incidental catch re- DEEPWATER/OTHER SHARK SPECIES tention limits specified at § 635.24(b). Blotched catshark, Scyliorhinus meadi [64 FR 29135, May 28, 1999, as amended at 64 Broadgill catshark, Apristurus riveri FR 37705, July 13, 1999; 65 FR 42887, July 12, Chain dogfish, Scyliorhinus retifer Deepwater catshark, Apristurus profundorum 2000; 65 FR 47238, Aug. 1, 2000] Dwarf catshark, Scyliorhinus torrei Iceland catshark, Apristurus laurussoni APPENDIX A TO PART 635ÐSPECIES Marbled catshark, Galeus arae TABLES Smallfin catshark, Apristurus parvipinnis TABLE 1 OF APPENDIX A TO PART 635±OCEANIC Bigtooth cookiecutter, Isistius plutodus Blainville's dogfish, Squalus blainvillei SHARKS Bramble shark, Echinorhinus brucus A. Large coastal sharks: Broadband dogfish, Etmopterus gracilispinnis Caribbean lanternshark, Etmopterus hillianus 1. Ridgeback sharks: Cookiecutter shark, Isistius brasiliensis Sandbar, Carcharhinus plumbeus Cuban dogfish, Squalus cubensis Silky, Carcharhinus falciformis Flatnose gulper shark, Deania profundorum Tiger, Galeocerdo cuvieri Fringefin lanternshark, Etmopterus schultzi Great
    [Show full text]
  • And Their Functional, Ecological, and Evolutionary Implications
    DePaul University Via Sapientiae College of Science and Health Theses and Dissertations College of Science and Health Spring 6-14-2019 Body Forms in Sharks (Chondrichthyes: Elasmobranchii), and Their Functional, Ecological, and Evolutionary Implications Phillip C. Sternes DePaul University, [email protected] Follow this and additional works at: https://via.library.depaul.edu/csh_etd Part of the Biology Commons Recommended Citation Sternes, Phillip C., "Body Forms in Sharks (Chondrichthyes: Elasmobranchii), and Their Functional, Ecological, and Evolutionary Implications" (2019). College of Science and Health Theses and Dissertations. 327. https://via.library.depaul.edu/csh_etd/327 This Thesis is brought to you for free and open access by the College of Science and Health at Via Sapientiae. It has been accepted for inclusion in College of Science and Health Theses and Dissertations by an authorized administrator of Via Sapientiae. For more information, please contact [email protected]. Body Forms in Sharks (Chondrichthyes: Elasmobranchii), and Their Functional, Ecological, and Evolutionary Implications A Thesis Presented in Partial Fulfilment of the Requirements for the Degree of Master of Science June 2019 By Phillip C. Sternes Department of Biological Sciences College of Science and Health DePaul University Chicago, Illinois Table of Contents Table of Contents.............................................................................................................................ii List of Tables..................................................................................................................................iv
    [Show full text]
  • The Sharks of North America
    THE SHARKS OF NORTH AMERICA JOSE I. CASTRO COLOR ILLUSTRATIONS BY DIANE ROME PEEBLES OXFORD UNIVERSITY PRESS CONTENTS Foreword, by Eugenie Clark v Mosaic gulper shark, Centrophorus tesselatus 79 Preface vii Little gulper shark, Centrophorus uyato 81 Acknowledgments ix Minigulper, Centrophorus sp. A 84 Slender gulper, Centrophorus sp. B 85 Introduction 3 Birdbeak dogfish, Deania calcea 86 How to use this book 3 Arrowhead dogfish, Deaniaprofundorum 89 Description of species accounts 3 Illustrations 6 Family Etmopteridae, The Black Dogfishes Glossary 7 and Lanternsharks 91 Bibliography 7 Black dogfish, Centroscyllium fabricii 93 The knowledge and study of sharks 7 Pacific black dogfish, Centroscyllium nigrum 96 The shark literature 8 Emerald or blurred lanternshark, Etmopterus bigelowi 98 Lined lanternshark, Etmopterus bullisi 101 Broadband lanternshark, Etmopterus gracilispinis 103 A KEY TO THE FAMILIES OF Caribbean lanternshark, Etmopterus hillianus 105 NORTH AMERICAN SHARKS 11 Great lanternshark, Etmopterusprinceps 107 Fringefin lanternshark, Etmopterus schultzi 110 SPECIES ACCOUNTS 19 Green lanternshark, Etmopterus virens 112 Family Chlamydoselachidae, The Frill Shark 21 Family Somniosidae, The Sleeper Sharks 115 Frill shark, Chlamydoselachus anguineus 22 Portuguese shark, Centroscymnus coelolepis 117 Roughskin dogfish, Centroscymnus owstoni 120 Family Hexanchidae, The Cowsharks 26 Velvet dogfish, Zameus squamulosus \T1 Sharpnose sevengill, or perlon shark, Heptranchias Greenland shark, Somniosus microcephalus 124 perlo 28 Pacific sleeper
    [Show full text]
  • An At-Home Lesson for Grades 6-8 Produced By
    Florida's Fintastic Sharks and Rays An at-home lesson for grades 6-8 Produced by: 1 What are sharks and rays? Believe it or not, they’re a type of fish! When you think “fish”, you probably picture a trout or tuna—something you’d commonly see on the end of a hook or on a plate. But fishes come in all shapes and sizes, some with saxophone shaped bodies (seahorses!) or elongated like a snake (eels!). No matter the look, all fishes share the following key characteristics that classify them into this vertebrate group. So before we get into sharks and rays, let’s start with a more general overview that applies all types of fishes. While we’re at it, what is the correct plural version of the word “fish”? Well, it depends. If you are talking about more than one individual fish, the correct plural form is “fish” (I caught a bunch of fish today.). However, when scientists talk about multiple different types or groups of fish, the plural is “fishes” (My research focuses on coral reef fishes.) Fishes have the simplest of vertebrate hearts with only two chambers- one atrium and one ventricle. The atrium brings in de-oxygenated blood from the body, pumps it to the ventricle which sends blood to the Gills. Blood is oxygenated through the vessels in the gills and circulated throughout the body. The vertebral column in a fish runs down the middle of its back in a similar manner to humans. Not all fishes have bony vertebrae. Fishes are cold-blooded, or ectothermic.
    [Show full text]