DOCSLIB.ORG

Technical Reports for Deepwater Horizon Water Column Injury

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Technical Reports for Deepwater Horizon Water Column Injury WC_TR.12 Production Foregone Model September 8, 2015 Technical Reports for Deepwater Horizon Water Column Injury Assessment WC_TR.12: Evaluation of Production Foregone as the Result of Direct Kill of Fish and Invertebrate Individuals Authors: Deborah French McCay, Richard Balouskus, M. Conor McManus, Melanie Schroeder, Jill Rowe, and Erin Bohaboy Revised: Septembers, 2015 Project Number: 2011-144 RPS ASA 55 Village Square Drive, South Kingstown, Rl 02879 DWH-AR0285169 WC_TR 12 Production Foregone Model September 8, 2015 Table of Contents 1 Executive Summary .............................................................................................................................1 2 Introduction and Objectives ................................................................................................................4 3 Production Foregone Model ...............................................................................................................6 3.1 Description of Production Foregone Model ............................................................................ 6 3.1.1 Approach ............................................................................................................................. 6 3.1.2 Model Equations ..................................................................................................................7 3.2 Mortality and Growth Models ................................................................................................... 9 3.2.1 First Year Growth and Mortality M odels .........................................................................9 3.2.1.1 Models used for Fish ....................................................................................................10 3.2.1.1.1 Fish - Life Table Equations ................................................................................. 11 3.2.1.1.2 Fish - Initial Lengths .............................................................................................13 3.2.1.2 Models used for Invertebrates .....................................................................................14 3.2.1.2.1 Invertebrate - Life Table Equations ...................................................................14 3.2.1.2.2 Penaeid Shrimp .....................................................................................................16 3.2.2 Age 1 + Mortality M odel.....................................................................................................17 3.2.2.1 Fish................................................................................................................................. 17 3.2.2.2 Invertebrates ................................................................................................................. 18 3.2.3 Mortality Variance Estimates .......................................................................................... 19 3.3 Development of Life Tables and Production Foregone Calculations .............................. 19 4 Life History Parameter Model Inputs ............................................................................................. 21 4.1 Description of Parameters ........................................................................................................21 4.1.1 Early Life History Param eters .........................................................................................21 4.1.2 Age 1+ Life History Parameters .................................................................................. 22 4.2 Life History Parameters Literature Review ..........................................................................23 4.2.1 Data Sources and Availability of Needed Information ................................................ 23 4.2.2 Development of Life History Parameters for Model Input ...........................................24 4.3 Applied Life History Parameter Model Inputs .......................................................................26 5 Model Results .................................................................................................................................... 27 5.1 Evaluation of Life Table Model ................................................................................................27 5.1.1 Models .................................................................................................................................27 5.1.1.1 Fecundity Model 1 .......................................................................................................27 5.1.1.2 Fecundity Model II ..................................................................................................... 27 5.1.1.3 Matrix Model (Lambda) ...............................................................................................28 5.1.2 Results of Life Table Tests ...............................................................................................28 RPS ASA South Kingstown, Rl, USA 2 DWH-AR0285170 WC_TR 12 Production Foregone Model September 8, 2015 5.1.3 Comparisons of Modeled Survival Rates to Empirical Data .......................................29 5.2 Production Foregone per Individual ......................................................................................29 6 References ........................................................................................................................................33 Appendix A. Production Foregone: Comparison of Natural Mortality (M)Models .......................... 37 A.1 Literature Review of Available Natural Mortality Models ........................................................ 37 A.1.1 Fish........................................................................................................................................... 37 A. 1.1.1 Fish - Egg Natural Mortality Models .............................................................................37 A. 1.1.2 Fish - Larval Natural Mortality M odels ........................................................................38 A. 1.1.3 Fish - Juvenile and Adult Natural Mortality Models .................................................. 41 A.1.2 Invertebrate - Natural Mortality Models ............................................................................ 48 A. 1.3 Catch Curve Analysis ........................................................................................................49 A. 1.3.1 General Catch Curves ................................................................................................... 49 A. 1.3.2 Larval Catch Curves .......................................................................................................50 A.2 Evaluation of Life Table and First Year Survival Models used in Production Foregone Calculations ........................................................................................................................................... 52 A.2.1 Fish - First Year Survival Model Comparisons ................................................................ 52 A.2.2 Fish - Age 1+ Mortality Models ........................................................................................... 60 A.2.3 Invertebrates ........................................................................................................................... 64 A.3 Reference ...................................................................................................................................... 67 Appendix B. Production Foregone: Life History Parameters by Taxonomic Group - Available D ata ............................................................................................................................................................ 71 Appendix C. Production Foregone: Life History Parameters by Taxonomic Group - Model Input D ata ............................................................................................................................................................ 71 Appendix D. Production Foregone: Life History Parameters by Taxonomic Group - References ....................................................................................................................................................................71 Appendix E. Summary of Model Results - Life Table and Production Foregone per Individual by Species Group ..........................................................................................................................................71 Appendix F. Model Results - Production Foregone Model Workbooks by Taxon, Season and Size ............................................................................................................................................................. 71 Appendix G. Guidance for Navigating the Production Foregone Model Workbooks ....................72 RPS ASA South Kingstown, Rl, USA III DWH-AR0285171 WC_TR 12 Production Foregone Model September 8, 2015 List of Figures Figure A-1. Comparison of first year mortality models for red snapper (spring) with hatch length of 2 mm. Each model is plotted from hatch to 365 days. (McGurk 1986 larvae-Lorenzen 1996 is indistinguishable from McGurk 1986 larvae-McGurk 1987 fish) ....................................................... 55 Figure A-2. Comparison of first year mortality models for red snapper (spring) with hatch length of 2.0 mm. Each model is plotted from hatch to 50 days. (McGurk 1986 larvae-Lorenzen 1996 is indistinguishable from McGurk 1986 larvae-McGurk 1987 fish) ......................................................
Load more

Recommended publications
  • New and Emerging Technologies for Sustainable Fisheries: a Comprehensive Landscape Analysis
    Photo by Pablo Sanchez Quiza New and Emerging Technologies for Sustainable Fisheries: A Comprehensive Landscape Analysis Environmental Defense Fund | Oceans Technology Solutions | April 2021 New and Emerging Technologies for Sustainable Fisheries: A Comprehensive Landscape Analysis Authors: Christopher Cusack, Omisha Manglani, Shems Jud, Katie Westfall and Rod Fujita Environmental Defense Fund Nicole Sarto and Poppy Brittingham Nicole Sarto Consulting Huff McGonigal Fathom Consulting To contact the authors please submit a message through: edf.org/oceans/smart-boats edf.org | 2 Contents List of Acronyms ...................................................................................................................................................... 5 1. Introduction .............................................................................................................................................................7 2. Transformative Technologies......................................................................................................................... 10 2.1 Sensors ........................................................................................................................................................... 10 2.2 Satellite remote sensing ...........................................................................................................................12 2.3 Data Collection Platforms ......................................................................................................................
    [Show full text]
  • Marine Fish Conservation Global Evidence for the Effects of Selected Interventions
    Marine Fish Conservation Global evidence for the effects of selected interventions Natasha Taylor, Leo J. Clarke, Khatija Alliji, Chris Barrett, Rosslyn McIntyre, Rebecca0 K. Smith & William J. Sutherland CONSERVATION EVIDENCE SERIES SYNOPSES Marine Fish Conservation Global evidence for the effects of selected interventions Natasha Taylor, Leo J. Clarke, Khatija Alliji, Chris Barrett, Rosslyn McIntyre, Rebecca K. Smith and William J. Sutherland Conservation Evidence Series Synopses 1 Copyright © 2021 William J. Sutherland This work is licensed under a Creative Commons Attribution 4.0 International license (CC BY 4.0). This license allows you to share, copy, distribute and transmit the work; to adapt the work and to make commercial use of the work providing attribution is made to the authors (but not in any way that suggests that they endorse you or your use of the work). Attribution should include the following information: Taylor, N., Clarke, L.J., Alliji, K., Barrett, C., McIntyre, R., Smith, R.K., and Sutherland, W.J. (2021) Marine Fish Conservation: Global Evidence for the Effects of Selected Interventions. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK. Further details about CC BY licenses are available at https://creativecommons.org/licenses/by/4.0/ Cover image: Circling fish in the waters of the Halmahera Sea (Pacific Ocean) off the Raja Ampat Islands, Indonesia, by Leslie Burkhalter. Digital material and resources associated with this synopsis are available at https://www.conservationevidence.com/
    [Show full text]
  • Ecosystem Services Generated by Fish Populations
    AR-211 Ecological Economics 29 (1999) 253 –268 ANALYSIS Ecosystem services generated by fish populations Cecilia M. Holmlund *, Monica Hammer Natural Resources Management, Department of Systems Ecology, Stockholm University, S-106 91, Stockholm, Sweden Abstract In this paper, we review the role of fish populations in generating ecosystem services based on documented ecological functions and human demands of fish. The ongoing overexploitation of global fish resources concerns our societies, not only in terms of decreasing fish populations important for consumption and recreational activities. Rather, a number of ecosystem services generated by fish populations are also at risk, with consequences for biodiversity, ecosystem functioning, and ultimately human welfare. Examples are provided from marine and freshwater ecosystems, in various parts of the world, and include all life-stages of fish. Ecosystem services are here defined as fundamental services for maintaining ecosystem functioning and resilience, or demand-derived services based on human values. To secure the generation of ecosystem services from fish populations, management approaches need to address the fact that fish are embedded in ecosystems and that substitutions for declining populations and habitat losses, such as fish stocking and nature reserves, rarely replace losses of all services. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Ecosystem services; Fish populations; Fisheries management; Biodiversity 1. Introduction 15 000 are marine and nearly 10 000 are freshwa­ ter (Nelson, 1994). Global capture fisheries har­ Fish constitute one of the major protein sources vested 101 million tonnes of fish including 27 for humans around the world. There are to date million tonnes of bycatch in 1995, and 11 million some 25 000 different known fish species of which tonnes were produced in aquaculture the same year (FAO, 1997).
    [Show full text]
  • Fish Passage Engineering Design Criteria 2019
    FISH PASSAGE ENGINEERING DESIGN CRITERIA 2019 37.2’ U.S. Fish and Wildlife Service Northeast Region June 2019 Fish and Aquatic Conservation, Fish Passage Engineering Ecological Services, Conservation Planning Assistance United States Fish and Wildlife Service Region 5 FISH PASSAGE ENGINEERING DESIGN CRITERIA June 2019 This manual replaces all previous editions of the Fish Passage Engineering Design Criteria issued by the U.S. Fish and Wildlife Service Region 5 Suggested citation: USFWS (U.S. Fish and Wildlife Service). 2019. Fish Passage Engineering Design Criteria. USFWS, Northeast Region R5, Hadley, Massachusetts. USFWS R5 Fish Passage Engineering Design Criteria June 2019 USFWS R5 Fish Passage Engineering Design Criteria June 2019 Contents List of Figures ................................................................................................................................ ix List of Tables .................................................................................................................................. x List of Equations ............................................................................................................................ xi List of Appendices ........................................................................................................................ xii 1 Scope of this Document ....................................................................................................... 1-1 1.1 Role of the USFWS Region 5 Fish Passage Engineering ............................................
    [Show full text]
  • Symposium Review: Using Electronic Tags to Estimate Vital Rates in Fishes Brendan J
    COLUMN 2017 ANNUAL MEETING Symposium Review: Using Electronic Tags to Estimate Vital Rates in Fishes Brendan J. Runde | Center for Marine Sciences and Technology, Department of Applied Ecology, North Carolina State University, 303 College Cir., Morehead City, NC 28557. E-mail: [email protected] Julianne E. Harris | U.S. Fish and Wildlife Service Office, Columbia River Fish and Wildlife Conservation, Vancouver, WA Jeffrey A. Buckel | Center for Marine Sciences and Technology, Department of AppliedEcology, North Carolina State University, Morehead City, NC Accurate and precise estimates of vital rates, such as nat- discussion that concluded the session. Symposium presenta- ural and fishing mortality, can be challenging to obtain, but tions illustrated the breadth and depth of use of electronic are essential for stock assessment, fisheries management, and tags to estimate vital rates and the discussion stressed the conservation. Joseph Hightower pioneered a novel approach need for careful study design. As tag technology and ana- for estimating mortality rates—assigning fates of electroni- lytical approaches continue to improve, we suggest that elec- cally tagged fish using telemetry. Herein, we describe a day- tronic tagging studies will become even more valuable to help long symposium held at the 147th American Fisheries Society scientists and managers better understand fish biology and Meeting in 2017 dedicated to highlighting and discussing manage fisheries. current uses of and recent advancements in electronic tag- Accurate and precise estimates of vital rates such as fishing ging to estimate fish vital rates. In this review, we highlight mortality (F) and natural mortality (M) are necessary for stock the 18 presentations made in the symposium as well as the assessment, fisheries management, and conservation.
    [Show full text]
  • Little Fish, Big Impact: Managing a Crucial Link in Ocean Food Webs
    little fish BIG IMPACT Managing a crucial link in ocean food webs A report from the Lenfest Forage Fish Task Force The Lenfest Ocean Program invests in scientific research on the environmental, economic, and social impacts of fishing, fisheries management, and aquaculture. Supported research projects result in peer-reviewed publications in leading scientific journals. The Program works with the scientists to ensure that research results are delivered effectively to decision makers and the public, who can take action based on the findings. The program was established in 2004 by the Lenfest Foundation and is managed by the Pew Charitable Trusts (www.lenfestocean.org, Twitter handle: @LenfestOcean). The Institute for Ocean Conservation Science (IOCS) is part of the Stony Brook University School of Marine and Atmospheric Sciences. It is dedicated to advancing ocean conservation through science. IOCS conducts world-class scientific research that increases knowledge about critical threats to oceans and their inhabitants, provides the foundation for smarter ocean policy, and establishes new frameworks for improved ocean conservation. Suggested citation: Pikitch, E., Boersma, P.D., Boyd, I.L., Conover, D.O., Cury, P., Essington, T., Heppell, S.S., Houde, E.D., Mangel, M., Pauly, D., Plagányi, É., Sainsbury, K., and Steneck, R.S. 2012. Little Fish, Big Impact: Managing a Crucial Link in Ocean Food Webs. Lenfest Ocean Program. Washington, DC. 108 pp. Cover photo illustration: shoal of forage fish (center), surrounded by (clockwise from top), humpback whale, Cape gannet, Steller sea lions, Atlantic puffins, sardines and black-legged kittiwake. Credits Cover (center) and title page: © Jason Pickering/SeaPics.com Banner, pages ii–1: © Brandon Cole Design: Janin/Cliff Design Inc.
    [Show full text]
  • Catch and Release Fishing; Effects on Bass Populations
    Pennsylvania Fish and Boat Commission Harrisburg PA www.fish.state.pa.us Catch & Release Fishing; Effects on Bass Populations By PFBC Staff Catch-and-release fishing is often seen by the public as an effective way of keeping good-sized largemouth bass and smallmouth bass in a population so that these fish can be caught again. But does it work? That is, how well do bass survive catch and release, and are there things anglers can do to improve the odds? A lot of research has been conducted on this topic. Here we will discuss the facts of catch-and-release mortality and how anglers can help improve bass survival. Catch-and-release fishing has become the norm, instead of the exception. Anglers proudly proclaim they release their catch with bumper stickers, hats and t-shirts. But just because the bass swims away, its survival isn’t guaranteed. Many anglers wonder about bass survival after fishing tourna- ments, and if catch and release works to keep good-sized bass in their local lakes and rivers. Much research on this topic has been done in Pennsylvania and elsewhere. There are many issues that affect if a bass will survive being caught or not. By using the best practices possible, anglers can help bass survive. Mortality Mortality can come about two ways in fish; naturally and through fishing. Natural causes include disease or being eaten by a predator. Fishing mortality can come from either the fish being harvested by an angler or from injuries or stress from catch and release. The mortality rate of a waterway is a measure of how many fish die or are removed over a year.
    [Show full text]
  • Proposed Incidental Harassment Authorizations for Seismic Surveys in the Atlantic Ocean
    AMERICAN LITTORAL SOCIETY – ANIMAL LEGAL DEFENSE FUND – ANIMAL WELFARE INSTITUTE – CAPE FEAR RIVER WATCH – CENTER FOR A SUSTAINABLE COAST – CENTER FOR BIOLOGICAL DIVERSITY CET LAW – CLEAN OCEAN ACTION – COASTAL CONSERVATION LEAGUE – CONSERVATION LAW FOUNDATION – COOK INLETKEEPER – DEFENDERS OF WILDLIFE – THE DOLPHIN PROJECT – EARTH LAW CENTER – EARTHJUSTICE – ENVIRONMENT GEORGIA – THE HUMANE SOCIETY OF THE U.S. – INITIATIVE TO PROTECT JEKYLL ISLAND – INTERNATIONAL FUND FOR ANIMAL WELFARE – MATANZAS RIVERKEEPER – MIAMI WATERKEEPER – NATURAL RESOURCES DEFENSE COUNCIL – NORTH CAROLINA COASTAL FEDERATION – NORTH CAROLINA WILDLIFE FEDERATION – OCEAN CONSERVATION RESEARCH – ONE HUNDRED MILES – ST. JOHNS RIVERKEEPER – SATILLA RIVERKEEPER – SIERRA CLUB – SIERRA CLUB ATLANTIC CHAPTER – SIERRA CLUB CHAPTERS OF FLORIDA, GEORGIA, MAINE, MARYLAND, MASSACHUSETTS, NEW JERSEY, NORTH CAROLINA, SOUTH CAROLINA, AND VIRGINIA – SOUND RIVERS – SOUTH CAROLINA WILDLIFE FEDERATION – SOUTHERN ENVIRONMENTAL LAW CENTER – STOP OFFSHORE DRILLING IN THE ATLANTIC (SODA) – SURFRIDER FOUNDATION – WHALE AND DOLPHIN CONSERVATION – WORLD WILDLIFE FUND PUBLIC HEARINGS REQUESTED By Electronic Mail July 21, 2017 Ms. Jolie Harrison Chief, Permits and Conservation Division Office of Protected Resources National Marine Fisheries Service 1315 East-West Highway Silver Spring, MD 20910 [email protected] Re: Proposed incidental harassment authorizations for seismic surveys in the Atlantic Ocean Dear Ms. Harrison: On behalf of the Natural Resources Defense Council (“NRDC”), Center
    [Show full text]
  • (Engraulis Ringens) from 1961 to 1979*
    ON THE SEASONAL GROWTH, MONTHLY RECRUITMENT AND MONTHLY BIOMASS OF PERUVIAN ANCHOVETA (Engraulis ringens) FROM 1961 TO 1979* by D. Pauly1 and I. Tsukayama2 1 International Center for Living Aquatic Resources Management (ICLARM), MCC P.O. Box 1501, Makate, Metro Manila, Philippines 2 Instituto del Mar del Perú, Apartado Postal 22, Callao, Perú * ICLARM Contribution No. 145, PROCOPA Contribution No. 14. Resumen Se han examinado en detalle datos de longitud-captura mensual de anchoveta peruana (Engraulis ringens) correspondientes a la region Norte, usando los programas de computadora ELEFAN I y III (Electronic LEngth Frequency ANalysis). ELEFAN I proporcionó para cada uno de los años, desde 1961 a 1979, valores similares de Ly K de la ecuación de crecimiento de Von Bertalanffy. Se muestra que ocurren oscilaciones estacionales en el crecimiento, los cuales son cuantificados. El programa ELEFAN III, que permite la aplicación de diferentes formas del análisis de población virtual en base a datos de longitud-captura, fue empleado para obtener series de tiempo, sobre una base mensual, de los siguientes parámetros: reclutamiento (R), stock desovante (S) y biomasa total (B). También se presentan y discuten series de tiempo de capturas mensuales (C) y de valores derivados (loge (R/S) y F = C/B). INTRODUCTION For about 10 years (1962–1971), the Peruvian anchoveta (Engraulis ringens, Jenyns [Fam: Engraulidae]) supported the largest single-species fishery in the world, with annual catches in excess of 12 million tonnes. Present catches are lower, but still make this species a very important aquatic resource (see contributions in Glantz and Thompson, 1981). The anchoveta has been much studied, and indeed, most methods available for assessing exploited fish stocks have been applied to the anchoveta, often by the very scientists who developed these methods (Boerema et al., 1967; Schaefer, 1967; Gulland, 1968; IMARPE, 1970, 1972, 1973, 1974, 1977a).
    [Show full text]
  • Reducing Discards and Unwanted Bycatch in European Trawl Fisheries
    Reducing d iscard s and unwanted bycatch in European trawl fisheries POSITION PAPER WWF’s mission is to conserve nature and ecological processes, while ensuring the sustainable use of renewable resources. As such, WWF works with governments and stakeholders to achieve sustainable fisheries through the implementation of ecosystem-based management March 2007 of all maritime activities. Introduction – bycatch and discards Most fisheries catch animals that were not originally targeted. This extra catch is known as bycatch . Of this bycatch some will have a commercial value and are landed by fishermen. Often, however, a proportion is unwanted and subsequently discarded (i.e. thrown back dead or dying over the side). Such unwanted bycatch is a major environmental problem in European fisheries as it is wasteful and can lead to high levels of mortality among fish that could otherwise have helped re-build and replenish stocks. Discarding of mature animals represents an immediate loss of spawning stock biomass and it is clear that a package of measures are needed to address this problem if European fisheries are to be sustainable. There are solutions to bycatch but there is not going to be a one size fits all fix. Solutions will need to be tailored to individual fisheries in response to the main cause of discarding and will likely involve not one measure but a range of measures working together to reduce the level of unwanted fish mortality. The reasons for discards are many including high-grading, the capture of fish which are below legal minimum landings size, of low economic value, or of poor marketable quality.
    [Show full text]
  • November/December 2015
    november/december 2015 January/February 2009 DEPARTMENTS From The President 2 From The Editor 3 18 Parasite Treatment Reduces Flavobacterium Columnare GAA Activities 5 Infection In Tilapia Advocacy And Advances 10 De-Hai Xu, Ph.D.; Craig Shoemaker, Ph.D.; Dunhau Zhang, Ph.D. Advocate Advertisers 80 20 Increased Density Improves Feeding Response, Growth Performance In Grouper Ingrid Lupatsch, Ph.D. On the cover: 22 Study: Inbreeding Affects Body Weight, But Not Survival In White Shrimp Responsible aquaculture provides healthy food and important employ- Dr. Lidia de los Ríos-Pérez, Dr. Gabriel R. Campos-Montes, ment opportunities around the world. The Global Aquaculture Alliance Dr. Alfonso Martínez-Ortega, Dr. Héctor Castillo Juárez, has been proud to share this news through the Global Aquaculture Advo- Dr. Hugo H. Montaldo cate magazine. Please continue to read the new Advocate online. Photo by Noppharat_th. 26 Natural Feed Additive Improves Shrimp Productivity In Ecuador Demonstration Juan Carlos Valle; Peter Coutteau, Ph.D. Page 20 28 The Bottom Line Density Ups Feeding Feed And Water Quality Revisited Response In Grouper Thomas R. Zeigler, Ph.D. Contrary to common perceptions, 32 Sustainable Aquaculture Practices grouper stocked at high density had Efficiency Of Mechanical Aeration greater feed intake and better feed Claude E. Boyd, Ph.D. conversion. 35 Biofilter Inoculation In Recirculating Aquaculture Systems Dr. Adrian A. Bischoff, Laura Koch, Marcus Thon, Prof. Dr. Bela H. Buck Page 66 37 Dietary Acidification In Aquaculture Enhanced AHPND Detection Christian Lückstädt, Ph.D. A study found that shrimp allowed to decompose prior to processing 39 Maximizing Nutrition For Adult Marine Fish reflected improved PCR detection of AHPND.
    [Show full text]
  • Factors Associated with Baseline Mortality in Norwegian Atlantic Salmon Farming Victor H
    www.nature.com/scientificreports OPEN Factors associated with baseline mortality in Norwegian Atlantic salmon farming Victor H. S. Oliveira1*, Katharine R. Dean1, Lars Qviller1, Carsten Kirkeby2 & Britt Bang Jensen1 In 2019, it was estimated that more than 50 million captive Atlantic salmon in Norway died in the fnal stage of their production in marine cages. This mortality represents a signifcant economic loss for producers and a need to improve welfare for farmed salmon. Single adverse events, such as algal blooms or infectious disease outbreaks, can explain mass mortality in salmon cages. However, little is known about the production, health, or environmental factors that contribute to their baseline mortality during the sea phase. Here we conducted a retrospective study including 1627 Atlantic salmon cohorts put to sea in 2014–2019. We found that sea lice treatments were associated with Atlantic salmon mortality. In particular, the trend towards non-medicinal sea lice treatments, including thermal delousing, increases Atlantic salmon mortality in the same month the treatment is applied. There were diferences in mortality among production zones. Stocking month and weight were other important factors, with the lowest mortality in smaller salmon stocked in August–October. Sea surface temperature and salinity also infuenced Atlantic salmon mortality. Knowledge of what afects baseline mortality in Norwegian aquaculture can be used as part of syndromic surveillance and to inform salmon producers on farming practices that can reduce mortality. High mortality of farmed salmonids results in annual deaths of tens of millions of fsh across the world. Reports from some of the leading salmon producing countries (Norway, Chile, and the UK) show that the total mortality is increasing1–3.
    [Show full text]