DOCSLIB.ORG

Of the PETRALE SOLE

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Of the PETRALE SOLE Bulletin No. 153 POPULATION DYNAMICS· of the PETRALE SOLE, Eopsetta jordani, in waters off western Canada by K. S. Ketchen and C. R. Forrester Fisheries Research Board of Canada. Ottawa.,1966 POPULATION DYNAMICS OF THE PETRALE SOLE, EOPSETTA JORDAN!, IN WATERS OFF WESTERN CANADA Bulletins of the Fisheries Research Board of Canada are designed to assess and interpret current knowledge in scientific fields pertinent to Canadian fisheries. Recent numbers in this series are listed at the back of this Bulletin. Editor: J. C. STEVENSON Associate Editor: G. 1. PRITCHARD Assis tant Editor: R. H. WIGMORE Production: R. L. MacIntyre Fisheries Research Board of Canada Sir Charles Tupper Building Ottawa 8, Ontario, Canada The Board also publishes the Journal of the Fisheries Research Board of CalZada in annual volumes of monthly issues, and an Anllual Report. Fisheries Research Board of Canada publications are for sale by the Queen's Printer, Ottawa. Remittances must be in advance, payable in Canadian funds to the order of the Receiver General of Canada. Publications may be consulted at Board establishments located at Ottawa ; Nanaimo and Vancouver, B.C. ; Sault Ste. Marie and London, Ont. ; Ste. Anne de Bellevue and Grande-Riviere, Que. ; St. Andrews, N.B. ; Halifax and Dartmouth, N.S. ; Ellerslie, P.E.I. ; and st. John's, Nfld. BULLETIN No. 153 Population dynamics of the petrale sale, Eopsetta jordani, in waters off western Canada By K. S. Ketchen and C. R. Forrester Fisheries Research Board of Canada Biological Station, Nanaimo, B. C. FISHERIES RESEARCH BOARD OF CANADA Ottawa, 1966 © Crown Copyrights reserved Available by mail from the Queen's Printer, Ottawa, and at the following Canadian Government bookshops: OTTAWA Daly Building, Corner Mackenzie and Rideau TORONTO Mackenzie Building, 36 Adelaide St. East MONTREAL Alterna-Vie Building, ]]82 St. Catherine St. West WINNIPEG Mall Center Bldg., 499 Portage Avenue VANCOUVER 657 Granville Street or through your bookseller A deposit copy of this publication is also available for reference in public libraries across Canada Price $3.75 Catalogue No. Fs 94-153 Price subject to change without notice ROGER DUHAMEL, F.R.S.C. Queen's Printer and Controller of Stationery Ottawa, Canada 1966 iv Contents ABSTRACT, vii CHAPTER I. INTRODUCTION, Acknowledgments, 3 CHAPTER II. HISTORY OF THE PETRALE SOLE FISHERY, 4 1. The United States fishery, 4 2. The Canadian fishery, 9 CHAPTER III. DEFINITION OF STOCKS, 13 1. Results of inshore tagging, 16 2. Results of deep-water tagging, 36 3. Boundaries of stocks, 42 CHAPTER IV. STATISTICS OF CATCH AND CATCH PER UNIT OF EFFORT, 43 1. General statistics of catch, 43 2. Statistics of catch per unit of effort, 53 CHAPTER V. CHANGES IN LENGTH AND AGE COMPOSITION OF CANADIAN PETRALE SOLE STOCKS, 79 1. Method of sampling, 79 2. Changes in length composition, 80 3. Changes in age composition, 86 CHAPTER VI. MEASURES OF RECRUITMENT, 94 1. Length-weight relationship, 94 2. Conversion to numbers of fish per unit of effort, 95 3. Variations in year-class strength in the southern stock, 99 4. Variations in year-class strength in the northern stock, 105 5. Summary, 107 CHAPTER VII. GROWTH OF THE PETRALE SOLE, 108 CHAPTER VIII. FOOD HABITS OF THE PETRALE SOLE, 114 CHAPTER IX. SIZE AND AGE AT MATURITY, 116 CHAPTER X. MORTALITY RATES, 118 1. Estimates of total mortality rate, 118 2. Estimates of natural mortality rate, 122 3. Estimates of fishing mortality rate, 126 4. Summary, 129 v Contents - Concluded CHAPTER XI. PATTERN OF RECRUITMENT TO THE FISHERY, 130 1. Size and age of recruitment to the fishing grounds, 130 2. Entry to the exploited phase, 135 CHAPTER XII. YIELD PER RECRUITMENT, 145 1. Introduction, 145 2. Choice of population model, 146 3. Results, 148 4. Conclusions, 150 CHAPTER XIII. FACTORS INFLUENCING RECRUITMENT, 153 1. The critical stage, 154 2. Transport mechanism, 155 3. Variability of survival, 155 4. The petrale sole and its environment, 157 5. Hypotheses regarding survival, 163 6. Prediction of petrale sole abundance, 164 CHAPTER XIV. REGULATION OF THE PETRALE SOLE FISHERY, 166 1. The question of optimum fishing, 166 2. Consequences of a spawning ground fishery, 169 3. Future outlook, 172 4. Research programs past and future, 175 CHAPTER XV. SUMMARY, 177 REFERENCES, 182 ApPENDICES, 185 I. Scientific and common names of species, 187 II. Agreement between Canada and the United States to restrict winter fishing for petrale sole, 187 III. Estimation of Washington catch of petrale sole by area in the years 1939-47, inclusive, 188 IV. Monthly landings of petrale sole from Area 3C, 190 V. Observed relationship between total length and mean weight of petrale sole, 191 VI. Average length by age of male and female petrale sole contained in Canadian landings from Area 3C, 192 VII. Back-calculation of lengths of petrale sole at ages I-IV, 194 vi ABSTRACT The petrale sole is an important contributor to the trawl fishery along the west coast of North America. Results of tagging suggest that there are two main units of stock in British Columbia waters, one offsou thern Vancouver Island and the other to the northward, mainly in Queen Charlotte Sound and Hecate Strait. Sharp reduc­ tion in abundance occurred in both stocks after the inception of fishing. Paralleling classical examples, average size and age decreased in catches from the southern stock until 1947, but this trend was reversed between 1948 and 1955 and accompanied a continued decline in abundance. Timing of the rising trend in size and age composi­ tion was the same in both the southern and northern stocks, though the histories of exploitation were different, thus indicating trends in recruitment. Year-classes of 1940-1943 contributed strongly to the fishery, but succeeding year-classes to 1949 were progressively weaker. Thereafter, there was some recovery, and early perform­ ance of the 1958 year-class suggests that it is of about the same size as those of the early 1940s. Growth of petrale sole, for practical purposes, conforms with the von Berta­ lanffy growth equation, the growth coefficient, K, being 0.160 for males and 0.167 for females, with corresponding asymptotic lengths, Leo, being 49.0 cm and 58.6 cm. Fifty percent of male fishmature at a length of 38 cm or age VII, while corresponding figures for females are 44 cm and VIII years. A verage instantaneous total mortality rate Z of the strong year-classes 1940-43 is estimated as 0.70 for males and 0.45 for females. Best estimate of instantaneous natural mortality rate (M) is 0.25 and 0.20 for the two sexes respectively, whence average instantaneous rate of fishing (F) is 0.45 for males and 0.25 for females. Alternatively, consideration is also given to the possibility that the indicated sex difference in Z is due largely to a differencein M, namely, M is 0.45 for males and 0.20 for females, whence F is 0.25 for both sexes. These two possibilities, when incorporated in models of yield per recruitment, lead to essentially the same conclu­ sion, viz. a modest increase in yield (2-12%) theoretically could be achieved by reduction in the minimum size of fishretained for market, and/or by more intensive fishing. However, the models are of restricted usefulness because of the observed trends in recruitment, possible trends in effective fishing effort (lack of equilibrium conditions), and because they do not permit prediction of effects of fishing on highly vulnerable spawning concentrations. Variations in year-class strength appear to be correlated with variations in the environment at the time of the pelagic egg and larval stages, as indicated by seawater temperatures and geostrophic wind patterns. Discussion is provided on the consequences of unrestricted fishing of spawning concentrations and on prospects for future regulation of the fishery. vii Chapter I INTRODUCTION During World War II, exploitation of demersal fishes by means of otter­ trawling underwent rapid development in the northeastern Pacific Ocean, particu­ larly in waters adjacent to Canada and the northwestern United States. Stimulation for expansion of this industry, which for nearly three decades had been confined largely to sheltered inshore waters, was gained from the sharp increase in demand for foodfishto offset war-time meat shortages and for supplies of vitamin A (prin­ cipally from dogfish liver) . Among the numerous species which contributed heavily FIG. 1. The petrale sole, Eopsetta jordani (Lockington) . to the offshore fishery in its initial stages was the petrale sole, or brill, Eopsetta jordani (Lockington) .l This is a relatively large member of the family Pleuronectidae (Fig. 1), closely related to the genus Hippoglossoides and restricted in its distribu­ tion to the northeastern Pacific between the Gulf of Alaska and lower California. One other member of the genus (E. grigOljewi) occurs in the western Pacificbetween Japan and Formosa (Norman, 1934, p. 309). IThe name petrale sole is used throughout because of its more general acceptance by industry and international scientific circles. "Brill" is in common usage among Canadian fishermen and is the name accepted by Clemens and Wilby (1961). The latter name presumably can be traced to fishermen from Great Britain where "brill" refers to Scophthalmus rhombus which resembles the petrale sole only vaguely and belongs to a different family (Bothidae). Because of its large size and excellent quality as a fresh or frozen fillet product, the petrale sole has commanded the highest price among the various species of flatfish landed for market, with the exception of halibut which is landed exclu­ sively by the long-established and well-known setline fishery. Until about 1949, product ion of petrale sole kept pace with the general ex­ pansion of the trawl fisheryof f the Canadian coast, but thereafter declined steadily in spite of continued high demand and improvement in fishing techniques.
Load more

Recommended publications
  • FISH LIST WISH LIST: a Case for Updating the Canadian Government’S Guidance for Common Names on Seafood
    FISH LIST WISH LIST: A case for updating the Canadian government’s guidance for common names on seafood Authors: Christina Callegari, Scott Wallace, Sarah Foster and Liane Arness ISBN: 978-1-988424-60-6 © SeaChoice November 2020 TABLE OF CONTENTS GLOSSARY . 3 EXECUTIVE SUMMARY . 4 Findings . 5 Recommendations . 6 INTRODUCTION . 7 APPROACH . 8 Identification of Canadian-caught species . 9 Data processing . 9 REPORT STRUCTURE . 10 SECTION A: COMMON AND OVERLAPPING NAMES . 10 Introduction . 10 Methodology . 10 Results . 11 Snapper/rockfish/Pacific snapper/rosefish/redfish . 12 Sole/flounder . 14 Shrimp/prawn . 15 Shark/dogfish . 15 Why it matters . 15 Recommendations . 16 SECTION B: CANADIAN-CAUGHT SPECIES OF HIGHEST CONCERN . 17 Introduction . 17 Methodology . 18 Results . 20 Commonly mislabelled species . 20 Species with sustainability concerns . 21 Species linked to human health concerns . 23 Species listed under the U .S . Seafood Import Monitoring Program . 25 Combined impact assessment . 26 Why it matters . 28 Recommendations . 28 SECTION C: MISSING SPECIES, MISSING ENGLISH AND FRENCH COMMON NAMES AND GENUS-LEVEL ENTRIES . 31 Introduction . 31 Missing species and outdated scientific names . 31 Scientific names without English or French CFIA common names . 32 Genus-level entries . 33 Why it matters . 34 Recommendations . 34 CONCLUSION . 35 REFERENCES . 36 APPENDIX . 39 Appendix A . 39 Appendix B . 39 FISH LIST WISH LIST: A case for updating the Canadian government’s guidance for common names on seafood 2 GLOSSARY The terms below are defined to aid in comprehension of this report. Common name — Although species are given a standard Scientific name — The taxonomic (Latin) name for a species. common name that is readily used by the scientific In nomenclature, every scientific name consists of two parts, community, industry has adopted other widely used names the genus and the specific epithet, which is used to identify for species sold in the marketplace.
    [Show full text]
  • Collapse and Recovery of Marine Fishes
    letters to nature sulphide complexes, indicating that Cu sulphide clusters are more 7. Al-Farawati, R. & van den Berg, C. M. G. Metal-sulfide complexation in seawater. Mar. Chem. 63, 331–352 (1999). stable than Cu organic complexes. This explains why laboratory 8. Luther III, G. W., Rickard, D. T., Theberge, S. M. & Olroyd, A. Determination of metal (bi)sulfide cultures of oceanic phytoplankton have been observed to increase stability constants of Mn2+,Fe2+,Co2+,Ni2+,Cu2+, and Zn2+ by voltammetric methods. Environ. Sci. the production of total dissolved sulphides when the concentrations Technol. 30, 671–679 (1996). of free Cu and Zn in the culture media were increased22. Although 9. Helz, G. R, Charnock, J. M., Vaughan, D. J. & Garner, C. D. Multinuclearity of aqueous copper and zinc bisulfide complexes—an EXAFS investigation. Geochim. Cosmochim. Acta 57, the data that we report here suggest that metal sulphide formation is 15–25 (1993). a means of detoxifying trace metals for organisms, further toxico- 10. Luther III, G. W., Theberge, S. M. & Rickard, D. T. Evidence for aqueous clusters as intermediates logical studies are needed to quantify the roles both sulphides and during zinc sulfide formation. Geochim. Cosmochim. Acta 19/20, 3159–3169 (1999). ‘natural’ organic ligands play in controlling Cu toxicity in natural 11. Peters, J. W., Lanzilotta, W. N., Lemon, B. J. & Seefeldt, L. C. X-ray crystal structure of the Fe-only hydrogenase (Cpl) from Clostridium pasteurianum to 1.8 angstrom resolution. Science 282, 1853– waters. 1858 (1998). Sulphur complexation may have a dramatic effect on the acute 12.
    [Show full text]
  • Industry Survey Turbot and Brill in the North Sea
    Industry survey turbot and brill in the North Sea Set up and results of a fisheries-independent survey using commercial fishing vessels 2018-2020 Authors: Edward Schrama, Niels Hintzena, Jurgen Batsleera, Tony Wilkesa, Katinka Bleekera, Wageningen University & Morgane Amelota, Wouter van Broekhovenb, David Rasb, Emma de Boerc, Brita Trapmanc, Research report C037/21 Nathalie A. Steinsa Industry survey turbot and brill in the North Sea Set up and results of a fisheries-independent survey using commercial fishing vessels 2018-2020 Authors: Edward Schrama, Niels Hintzena, Jurgen Batsleera, Tony Wilkesa, Katinka Bleekera, Morgane Amelota, Wouter van Broekhovenb, David Rasb, Emma de Boerc, Brita Trapmanc, Nathalie A. Steinsa a Wageningen Marine Research b Cooperatie Kottervisserij Nederland U.A. (VisNed) c Nederlandse Vissersbond Wageningen Marine Research IJmuiden, April 2021 Wageningen Marine Research report C037/21 Keywords: Industry survey, turbot, brill, stock assessment European Union, European Maritime and Fisheries Fund (EMFF) Client: Rijksdienst voor Ondernemend Nederland Attn.: A.P.M. Vaessen Postbus 93144 2509 AC, Den Haag This report can be downloaded for free from https://doi.org/10.18174/544588 Wageningen Marine Research provides no printed copies of reports Wageningen Marine Research is ISO 9001:2015 certified. Photo cover: Edward Schram © Wageningen Marine Research Wageningen Marine Research, an institute Wageningen Marine Research accepts no liability for consequential damage, nor within the legal entity Stichting for damage resulting from applications of the results of work or other data Wageningen Research (a foundation under obtained from Wageningen Marine Research. Client indemnifies Wageningen Dutch private law) represented by Marine Research from claims of third parties in connection with this application.
    [Show full text]
  • Forage Fish Management Plan
    Oregon Forage Fish Management Plan November 19, 2016 Oregon Department of Fish and Wildlife Marine Resources Program 2040 SE Marine Science Drive Newport, OR 97365 (541) 867-4741 http://www.dfw.state.or.us/MRP/ Oregon Department of Fish & Wildlife 1 Table of Contents Executive Summary ....................................................................................................................................... 4 Introduction .................................................................................................................................................. 6 Purpose and Need ..................................................................................................................................... 6 Federal action to protect Forage Fish (2016)............................................................................................ 7 The Oregon Marine Fisheries Management Plan Framework .................................................................. 7 Relationship to Other State Policies ......................................................................................................... 7 Public Process Developing this Plan .......................................................................................................... 8 How this Document is Organized .............................................................................................................. 8 A. Resource Analysis ....................................................................................................................................
    [Show full text]
  • 04-Bailly 669.Indd
    Scophthalmus Rafinesque, 1810: The valid generic name for the turbot, S. maximus (Linnaeus, 1758) [Pleuronectiformes: Scophthalmidae] by Nicolas BAILLY* (1) & Bruno CHANET (2) ABSTRACT. - In the past 50 years, the turbot is referred to either as Scophthalmus maximus (Linnaeus, 1758) or Psetta maxima (Linnaeus, 1758) in the literature. Norman (1931) had argued that the valid name for the turbot was Scophthalmus maximus. However, his recommendation was never universally accepted, and today the confusing situation exists where two generic names are still being used for this species. We address this issue by analysing findings from recently published works on the anatomy, molecular and morphological phylogenetic systematics, and ecology of scophthalmid fishes. The preponderance of evidence supports the strong recommendation to use Scophthalmus as the valid generic name for the tur- bot. Acceptance of this generic name conveys the best information available concerning the systematic relationships of this species, and also serves to simplify the nomenclature of scophthalmid flatfishes in publications on systematics, fisheries and aquaculture, fishery statistics, ichthyofaunal and field guides for the general public, and in various legal and conserva- tion-related documents. This paper reinforces the conclusions of Chanet (2003) with more arguments. RÉSUMÉ. - Scophthalmus Rafinesque, 1810: le nom de genre valide du turbot,S. maximus (Linnaeus, 1758) (Pleuronecti- formes: Scophthalmidae). Depuis 50 ans, le turbot est dénommé dans la littérature soit Scophthalmus maximus (Linnaeus, 1758), soit Psetta maxima (Linnaeus, 1758). Norman (1931) avait montré que le nom valide pour le turbot était Scophthalmus maximus. Cependant, sa recommandation ne fut jamais universellement appliquée, et aujourd’hui la situation reste confuse avec deux noms génériques en usage pour cette espèce.
    [Show full text]
  • Why Are There So Many Flatfishes? Jaw Asymmetry, Diet, and Diversification in the Pleuronectiformes
    Why are there so many flatfishes? Jaw asymmetry, diet, and diversification in the Pleuronectiformes Jonathan Chang1 Functional Morphology and Ecology of Fishes Summer 2014 1Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA. Contact information: Jonathan Chang 610 Charles E. Young Drive S Los Angeles CA 90095 [email protected] Keywords: flatfish, Pleuronectidae, Paralichthyidae, Bothidae, asymmetry, geometric morphometrics, comparative methods, functional morphology Chang 1 Abstract Flatfishes (Actinopterygii: Pleuronectiformes) are a diverse group of teleost fishes, with over 700 species in the order. Jaw asymmetry and diet have been thought to contribute to flatfish diversity but this has not yet been tested in a comparative framework. Here I use geometric morphometric and comparative methods to test whether ocular-blind side asymmetry in flatfish head morphology contributed to flatfish diversification. I find that the repeated convergent evolution of similar morphology, jaw function, and diet likely contribute to the high diversity of flatfishes. Introduction Pleuronectiform fishes are highly diverse, with over 700 described species (Froese and Pauly, 2014). These fishes are characterized by their unique bilateral asymmetry and their benthic ecology. Flatfishes also generally consume one of three main types of prey: buried infauna, pelagic fishes and crustaceans, and a third type intermediate to the first two (de Groot 1971, Tsuruta & Omori 1976). I hypothesize that this specialization into different prey types has driven the diversification and morphological disparity in asymmetry of flatfish species. Methods 12 species of flatfish comprising of 11 genera and 2 families (Table 1) were collected via trawl and seine at these sites: Jackson Beach, [48°31'13.0"N 123°00'35.1"W] and Orcas – Eastsound [48°38'26.9"N 122°52'14.0"W].
    [Show full text]
  • Pleuronectidae
    FAMILY Pleuronectidae Rafinesque, 1815 - righteye flounders [=Heterosomes, Pleronetti, Pleuronectia, Diplochiria, Poissons plats, Leptosomata, Diprosopa, Asymmetrici, Platessoideae, Hippoglossoidinae, Psettichthyini, Isopsettini] Notes: Hétérosomes Duméril, 1805:132 [ref. 1151] (family) ? Pleuronectes [latinized to Heterosomi by Jarocki 1822:133, 284 [ref. 4984]; no stem of the type genus, not available, Article 11.7.1.1] Pleronetti Rafinesque, 1810b:14 [ref. 3595] (ordine) ? Pleuronectes [published not in latinized form before 1900; not available, Article 11.7.2] Pleuronectia Rafinesque, 1815:83 [ref. 3584] (family) Pleuronectes [senior objective synonym of Platessoideae Richardson, 1836; family name sometimes seen as Pleuronectiidae] Diplochiria Rafinesque, 1815:83 [ref. 3584] (subfamily) ? Pleuronectes [no stem of the type genus, not available, Article 11.7.1.1] Poissons plats Cuvier, 1816:218 [ref. 993] (family) Pleuronectes [no stem of the type genus, not available, Article 11.7.1.1] Leptosomata Goldfuss, 1820:VIII, 72 [ref. 1829] (family) ? Pleuronectes [no stem of the type genus, not available, Article 11.7.1.1] Diprosopa Latreille, 1825:126 [ref. 31889] (family) Platessa [no stem of the type genus, not available, Article 11.7.1.1] Asymmetrici Minding, 1832:VI, 89 [ref. 3022] (family) ? Pleuronectes [no stem of the type genus, not available, Article 11.7.1.1] Platessoideae Richardson, 1836:255 [ref. 3731] (family) Platessa [junior objective synonym of Pleuronectia Rafinesque, 1815, invalid, Article 61.3.2 Hippoglossoidinae Cooper & Chapleau, 1998:696, 706 [ref. 26711] (subfamily) Hippoglossoides Psettichthyini Cooper & Chapleau, 1998:708 [ref. 26711] (tribe) Psettichthys Isopsettini Cooper & Chapleau, 1998:709 [ref. 26711] (tribe) Isopsetta SUBFAMILY Atheresthinae Vinnikov et al., 2018 - righteye flounders GENUS Atheresthes Jordan & Gilbert, 1880 - righteye flounders [=Atheresthes Jordan [D.
    [Show full text]
  • Status of Petrale Sole (Eopsetta Jordani) Along the U.S. West Coast in 2019
    Status of petrale sole (Eopsetta jordani) along the U.S. west coast in 2019 Chantel R. Wetzel1 1Northwest Fisheries Science Center, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 2725 Montlake Boulevard East, Seattle, Washington 98112 October 2019 This report may be cited as: Wetzel, C.R. 2019. Status of petrale sole (Eopsetta jordani) along the U.S. west coast in 2019. Pacific Fishery Management Council, 7700 Ambassador Place NE, Suite 101, Portland, OR97220. 2 Status of petrale sole (Eopsetta jordani) along the U.S. west coast in 2019 Contents Executive Summaryi Stock...........................................i Landings . .i Data and Assessment . iv Updated Data . iv Stock Biomass . .v Recruitment . viii Exploitation Status . .x Ecosystem Considerations . xiii Reference Points . xiii Management Performance . xiv Unresolved Problems and Major Uncertainties . xv Decision Table . xvi Scientific Uncertainty . xix Research and Data Needs . xix 1 Introduction1 1.1 Basic Information . .1 1.2 Life History . .2 1.3 Ecosystem Considerations . .2 1.4 Historical and Current Fishery Information . .2 1.5 Summary of Management History and Performance . .4 1.6 Fisheries off Canada and Alaska . .5 i 2 Data 5 2.1 Fishery-Independent Data . .6 2.1.1 NWFSC West Coast Groundfish Bottom Trawl Survey . .6 2.1.2 AFSC/NWFSC West Coast Triennial Shelf Survey . .8 2.2 Fishery-Dependent Data . .9 2.2.1 Commercial Fishery Landings . .9 2.2.2 Discards . 10 2.2.3 Fishery Length and Age Data . 11 2.2.4 Historical Commercial Catch-Per-Unit Effort/Logbooks . 12 2.2.5 Foreign Landings .
    [Show full text]
  • Brill (Scophthalmus Rhombus) in Subarea 4 and Divisions 3.A and 7.D–E (North Sea, Skagerrak and Kattegat, English Channel)
    ICES Advice on fishing opportunities, catch, and effort Celtic Seas and Greater North Sea ecoregions Published 30 June 2020 Brill (Scophthalmus rhombus) in Subarea 4 and divisions 3.a and 7.d–e (North Sea, Skagerrak and Kattegat, English Channel) ICES advice on fishing opportunities Please note: The present advice replaces the advice given in June 2019 for catches in 2021 ICES advises that when the precautionary approach is applied, catches in 2021 should be no more than 2047 tonnes. Management of brill and turbot under a combined species TAC prevents effective control of the single-species exploitation rates and could lead to the overexploitation of either species. ICES advises that management should be implemented at the species level in the entire stock distribution area (Subarea 4 and divisions 3.a and 7.d–e). Note: This advice sheet is abbreviated due to the COVID-19 disruption. The previous biennial advice issued for 2020 and 2021 is attached as Annex 1.The advice for brill is now issued annually. Stock development over time Figure 1 Brill in Subarea 4 and divisions 3.a and 7.d–e. Summary of the stock assessment. Biomass index is the standardized landings per unit effort (LPUE) from the Dutch beam-trawl fleet for vessels > 221 kW. The red horizontal lines show the mean stock indicators for 2018–2019 and 2015–2017. The landings below minimum conservation reference size (BMS) are those officially reported. Stock and exploitation status Table 1 Brill in Subarea 4 and divisions 3.a and 7.d–e. State of the stock and the fishery relative to proxy reference points.
    [Show full text]
  • The IUCN Red List of Threatened Speciestm
    Species 2014 Annual ReportSpecies the Species of 2014 Survival Commission and the Global Species Programme Species ISSUE 56 2014 Annual Report of the Species Survival Commission and the Global Species Programme • 2014 Spotlight on High-level Interventions IUCN SSC • IUCN Red List at 50 • Specialist Group Reports Ethiopian Wolf (Canis simensis), Endangered. © Martin Harvey Muhammad Yazid Muhammad © Amazing Species: Bleeding Toad The Bleeding Toad, Leptophryne cruentata, is listed as Critically Endangered on The IUCN Red List of Threatened SpeciesTM. It is endemic to West Java, Indonesia, specifically around Mount Gede, Mount Pangaro and south of Sukabumi. The Bleeding Toad’s scientific name, cruentata, is from the Latin word meaning “bleeding” because of the frog’s overall reddish-purple appearance and blood-red and yellow marbling on its back. Geographical range The population declined drastically after the eruption of Mount Galunggung in 1987. It is Knowledge believed that other declining factors may be habitat alteration, loss, and fragmentation. Experts Although the lethal chytrid fungus, responsible for devastating declines (and possible Get Involved extinctions) in amphibian populations globally, has not been recorded in this area, the sudden decline in a creekside population is reminiscent of declines in similar amphibian species due to the presence of this pathogen. Only one individual Bleeding Toad was sighted from 1990 to 2003. Part of the range of Bleeding Toad is located in Gunung Gede Pangrango National Park. Future conservation actions should include population surveys and possible captive breeding plans. The production of the IUCN Red List of Threatened Species™ is made possible through the IUCN Red List Partnership.
    [Show full text]
  • 1 Students Look at Images of Fish Caught by an Otter Trawl Net Off
    BIOGEOGRAPHY OR WHAT HAPPENS TO FISH POPULATIONS DURING EL NIÑO OVERVIEW Students look at images of fish caught by an otter trawl net off southern California. Using fish charts provided in this activity, they identify the fish and record their geographic range. The fish were collected in May 1997, shortly after the beginning of a major El Niño event. Students see what effects the El Niño had on fish population during its early stages. CONCEPTS • In a given area fish populations can change as water conditions (e.g., temperature) change off- shore due to El Niño effects. • Effects of an El Niño occur over time, so the U.S. west coast may not show significant effects for several months after an El Niño begins developing in equatorial waters. MATERIALS • Movie of fish catch included with this activity (activity can be done without the movie) • Fish Keys (included) • “Catch of the Day” sheet (included) • Paper and pencil to record results • Atlas or map with geographical information about the U.S. west coast (if needed) PREPARATION Divide students into small groups. Make copies of Fish Key and Catch of the Day sheets, one for each group. PROCEDURE Engagement An El Niño event is thought to be triggered when steady westward blowing trade winds weaken and even reverse direction. This change in the winds allows the large mass of warm water that is normally located near Australia to move eastward along the equator until it reaches the coast of South America. It then spreads out along the western coasts of the Americas, affecting water temperatures and weather patterns.
    [Show full text]
  • Integration Drives Rapid Phenotypic Evolution in Flatfishes
    Integration drives rapid phenotypic evolution in flatfishes Kory M. Evansa,1, Olivier Larouchea, Sara-Jane Watsonb, Stacy Farinac, María Laura Habeggerd, and Matt Friedmane,f aDepartment of Biosciences, Rice University, Houston, TX 77005; bDepartment of Biology, New Mexico Institute of Mining and Technology, Socorro, NM 87801; cDepartment of Biology, Howard University, Washington, DC 20059; dDepartment of Biology, University of North Florida, Jacksonville, FL 32224; eDepartment of Paleontology, University of Michigan, Ann Arbor, MI 48109; and fDepartment of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109 Edited by Neil H. Shubin, University of Chicago, Chicago, IL, and approved March 19, 2021 (received for review January 21, 2021) Evolutionary innovations are scattered throughout the tree of life, organisms and is thought to facilitate morphological diversifica- and have allowed the organisms that possess them to occupy tion as different traits are able to fine-tune responses to different novel adaptive zones. While the impacts of these innovations are selective pressures (27–29). Conversely, integration refers to a well documented, much less is known about how these innova- pattern whereby different traits exhibit a high degree of covaria- tions arise in the first place. Patterns of covariation among traits tion (21, 30). Patterns of integration may be the result of pleiot- across macroevolutionary time can offer insights into the gener- ropy or functional coupling (28, 30–33). There is less of a ation of innovation. However, to date, there is no consensus on consensus on the macroevolutionary implications of phenotypic the role that trait covariation plays in this process. The evolution integration.
    [Show full text]