Coho Fry

Dr. Duane Barker

Dr. Duane Barker holding fish samples at the beach

Building 480, Room 112
Email: Duane.Barker@viu.ca

  • Fish Ecology
  • Aquaculture
  • Ecotoxicology
  • Environmental monitoring and consulting

Dr. Duane Barker has been at VIU since 2005, but has more than 25 years of experience in aquatic animal health research and over 30 years of university teaching at four different universities. Duane has a strong passion for teaching and has taught many university courses, as well as developed and delivered many industry-training courses.

Being from coastal rural Newfoundland, Dr. Barker has always been drawn to the sea and his research has focused on aquatic industries of coastal communities. In 2015, he was awarded a New Brunswick Innovation Foundation Research Chair appointment at the Huntsman Marine Sciences Centre in St. Andrews, New Brunswick. While at Huntsman, Dr. Barker was involved with several aquaculture therapeutic product development studies and ecotoxicology assessments for private industry, pharmaceutical companies and government. One of his past major research projects in BC tested the role of sea lice as vectors of salmon pathogens and how the lice affect the salmon immune response. Previous research efforts have focused on Atlantic & Pacific fish and invertebrates with topics including: disease challenges, vaccine and immunostimulant testing, pathogen surveys, ecotoxicology, pathology, mark-recapture studies and population assessments.

Education

April 2000 - August 2001: NSERC Post-Doctoral Fellowship at the Huntsman Marine Science Centre (St. Andrews, New Brunswick) shared with the Atlantic Veterinary College (Charlottetown, PEI) and Saint Mary's University (Halifax, Nova Scotia).
Topic: Pathogens and parasites of wild and farmed Atlantic flatfishes.

Sept. 1994 - Sept. 1997: PhD (Biology), Dalhousie University, Halifax, Nova Scotia
Thesis: Metazoan parasite communities in the American eel, Anguilla rostrata: patterns, processes and applicability as biological indicators.

Sept. 1991 - Apr. 1993: Master of Science (Biology), Memorial University of Newfoundland
Thesis: Bioindicators of chronic stress in winter flounder, Pleuronectes americanus, living adjacent to a pulp and paper mill in western Newfoundland.

Jan. 1986 - Apr. 1990: Bachelor of Science - Honours (Marine Biology), Memorial University of Newfoundland
Thesis: Dietary analysis of Greenland halibut (turbot), Reinhardtius hippoglossoides, populations from the Grand Banks to Davis Strait.

Courses

  • FISH 115 (previously 211) Life History and Management of Salmonids
  • FISH 124 Biology of Fishes
  • FISH 127 Salmonid Husbandry
  • FISH 132 Aquatic Habitats
  • FISH 133 (formerly FISH 204) Aquatic Plants and Algae Ecology and Culture
  • FISH 241 Fish Health
  • FISH 324 Ichthyology
  • FISH 123 – Concepts in Biology
  • FISH 100T – Introductory Field Trip
  • FISH 191/192, 291/292, 392 - Applied Techniques in Aquatic Systems & Fisheries I-IV
  • FISH 281 - Freshwater Fisheries Field Techniques
  • FISH 322 - Coastal & Estuarine Ecosystems
  • FISH 453 – Fish Habitat Assessment & Rehabilitation
  • FISH 490 – Directed Studies in Fisheries & Aquaculture
  • FISH 491 – Undergraduate Research Project
  • BIOL 121 – Introductory Zoology
  • BIOL 122 - Introductory Botany
  • BIOL 315 – Parasitology

Student Supervision

Supervised 100+ students in past 25 years

  • Undergraduate:     50
  • Master:                    10      
  • Doctoral:                  3
  • Postdoctoral:           2      
  • Diploma:                53

Sample of VIU Undergraduate Student projects

Jessica Driver (2020) Reproduction and development of black ghost knifefish (Apteronotus albifrons) in captivity.

Amanda Friesen (2020) The prevalence and intensity of Gorgoderina attenuata (Trematoda) in invasive Bullfrogs (Lithobates catesbeianus) from Linley Valley Park, on Vancouver Island.

Stephen Johnston (2015) Preliminary observations in salinity tolerance of the diatom Didymosphenia geminata (Lyngbye) M.Schmidt in the Campbell River (British Columbia, Canada).

Tamara Russell (2015) To the surface and back: determining the photobiology of the toxic Raphidophyte Heterosigma akashiwo with emphasis on its diel migration in Departure Bay, British Columbia, Canada.

Lenora Turcotte (2015) The effects of stocking density on survival and growth in juvenile white sturgeon (Acipenser transmontanus).

Clayton Burgoyne (2015) Parasite Communities of the Gills of Thirteen Rockfish Species (Sebastes spp.)

Elsie Hampshire (2015) Helminth Community Ecology of the Western Belted Kingfisher, Megaceryle alcyon caurina.

Megan Morgan (2014) The relationships among Loma salmonae (Microsporidia), spawning pink salmon (Oncorhynchus gorbuscha), and environmental conditions in the Quinsam River, British Columbia, Canada.

Sarah Fraser (2013) Development of a PCR-based protocol to identify Myxobolus arcticus in sockeye salmon (Oncorhynchus nerka) using novel combinations of previously described 18S ribosomal DNA primers.

Heidi van Vliet (2013) Title: The use of the nematode Anisakis simplex and the copepod Bomolochus sp. as indicators of geographical location of Pacific Herring along the coast of British Columbia.

Karli Silvestrone (2012) The Behavioural Responses of Lepeophtheirus salmonis to Three Fish-Derived Stimuli.

Megan Rowland (2012) Using PCR techniques to assess the association of Aeromonas salmonicida with the salmon louse, Lepeophtheirus salmonis.

Brenna Collicutt (2011) Longevity of Aeromonas salmonicida on sea lice, Lepeophtheirus salmonis.

Katie Verkaik (2011) Does the bacteria, Aeromonas salmonicida, affect the survival and behavior of the sea louse, Lepeophtheirus salmonis?

Tamara Jane Bickerton (2011) Development of histological methods for the detection of infectious haematopoietic necrosis virus (IHNv).

Kate Rolheiser (2011) Assessment of Chemical Treatments for Controlling Didemnum vexillum, Biofouling Communities and Predatory Organisms in Shellfish Aquaculture.

Amanda Stull (2010) Examining the potential role of Lepeophtherius salmonis as a carrier for infectious haematopoietic necrosis virus (IHNv).

Remylee Martin (2010) Experimental transmission of Aeromonas salmonicida from sea lice, Lepeophtheirus salmonis to Atlantic (Salmo salar), Pink (Oncorhynchus gorbuscha) and Chum salmon (Oncorhynchus keta).

Danielle Lewis (2010) The ectoparasitic copepod (Lepeophtheirus salmonis) as a carrier of Aeromonas salmonicida infecting Atlantic salmon, Salmo salar.

Marie Sandeman-Allen (2010) Histological Detection of Bacterial Pathogens in Sea Lice, Lepeophtheirus salmonis.

Brittany McNish (2010) Is the Green Sea Urchin Pathogen Paramoeba invadens present around Vancouver Island?

Colin Novak (2009) The Ecology of the Frog Lung Fluke Haematoloechus longiplexus (Trematoda) in Odonates on Vancouver Island.

Carly Price (2009) Physid snails as indicators of Nematomorph presence on Vancouver Island.

Shaun van Pel (2009) In vitro Transfer of the Mobile Genetic Element, SCC mecA, Between Staphylococcus aureus and Coagulase-Negative Staphylococci.

Laura M. Braden (2007)Investigation into the relationship between Loma salmonae (Microsporea) and phagocytic cells using RTS11, a rainbow trout macrophage-like cell line.

Cameron Robinson (2008) Efficacy of AQUI-STM, Clove Oil and TMS anaesthesia using juvenile white sturgeon (Acipenser transmontanus): plasma glucose and haematological assessment.

Jacob Etzkorn (2008) Helminth parasites of the rhinoceros auklet, Cerorhinca monocerata, as biological indicators of heavy metal contamination in the marine environment.

J. David Switzer (2007) Sexing of White Sturgeon (Acipenser transmontanus) Using Non-Invasive Techniques.

Sample of Graduate Student Theses

Laura M. Braden (2015, PhD Thesis, UVic) Investigating the molecular basis for resistance to the sea louse, Lepeophtheirus salmonis, among salmonids.

Dr. Eva Jakob (2010-2012, Post-Doctoral Research, VIU/PBS)Vector potential of the salmon louse (Lepeophtheirus salmonis) in the transmission of infectious haematopoietic necrosis virus (IHNV).

Colin W. Novak (2013, MSc Thesis, UBC) The Salmon Louse Lepeophtheirus Salmonis (Caligidae) as a Vector of Aeromonas Salmonicida.

Danielle L. Lewis (2012, MSc Thesis, UBC) Interactions between salmon macrophages and pathogenic bacteria in the presence of secretions isolated from Lepeophtheirus salmonis.

Jennifer Monk (2008, MSc Thesis, MUN)The Effect of Varying Light Intensities and Tank Colour on the Growth, Foraging Behaviour and Survival of Atlantic Cod (Gadus morhua) Larvae.

Chimwemwe K. Soko (2005, MSc Thesis, MUN) Efficacy of Crushed Garlic and Lemon Juice as Bio-Product Treatments for Ichthyophthirius Multifiliis (‘Ich’) Infections Among Different Size Classes of Juvenile Nile Tilapia, Oreochromis Niloticus.

Crispin S. Jenkins (2005, MSc Thesis, MUN) The efficacy of oral immunostimulants in enhancing resistance against Microsporidiosis in juvenile Atlantic cod (Gadus morhua L.)

Research interests

a. Population and Ecosystem Assessment - Environmental Monitoring

  • Ecotoxicology analysis of acute and chronic exposure to bitumen and crude oil on Atlantic lobster and Atlantic salmon
  • Stream and lake microalgae and benthic macroinvertebrate biodiversity as environmental monitoring tools in BC and NS
  • Ecosystem effects assessments from industrial activities (e.g., expansion of Roberts Bank Terminal)
  • Intertidal health assessment (biodiversity analyses of invertebrates and seaweeds) in BC
  • Toxicity of ivermectin and emamectin benzoate on Atlantic lobster adults and juveniles
  • Parasites and fish pathology as pollution (pulp mill effluent, acid rain, petroleum hydrocarbons) indicators
  • Assessment of chronic stress and sublethal toxicity in wild fish (Atlantic cod, winter flounder, sculpin, eels)

b. Fisheries Biology - Aquatic Ecology

  • Mark recapture, ageing and dietary analysis (eels, winter flounder, turbot, sculpins, cutthroat trout, stickleback)
  • Parasite community ecology: local vs. regional patterns of fish parasite species richness
  • Parasites as indicators of fish migration/population markers (eels, Atlantic cod, flounder)
  • In situ spawning and territorial behaviour assessments (wrasse, salmon)
  • Benthic & subtidal fish and seaweed assemblage surveys in Resolute Bay, NWT and Bonne Bay, NL
  • Ordination techniques and multivariate statistical analyses

c. Pathogen Challenges, Disease Modelling and Diagnostics – Aquatic Animal Health Assessments

  • Farmed & wild salmonids: sea lice as vectors of bacterial and viral pathogens, diagnostics, molecular & cellular immunological responses, histopathology, mucus antibacterial bioassays, blood and reflex response stress testing, sea lice warm water shower
  • treatment, anaesthetic efficacy trials, therapeutant residue testing
  • Pathogen challenge trials, Saprolegnia infection model, vaccine efficacy testing, H2O2 and gas infusion testing, toxicity of
  • formalin on non-salmonids, immunostimulants
  • Non-salmonids (Atlantic cod, halibut, winter flounder, eels, lake whitefish, sturgeon) and shellfish (Pacific oyster, blue mussel,
  • green sea urchin, sea stars): parasite and pathogen diagnostics, disease epidemiology and histopathology assessments

Publications

1. Barker DE. & A. Garber.  First report of generational genetic variation in resistance to sea lice (Lepeophtheirus salmonis) among several yearclasses of farmed Atlantic salmon, Salmo salar L., in New Brunswick, Canada. (In prep for J. Fish Dis.)

2. Barker DE & A. Garber.  Genetic variation in resistance to bacterial kidney disease (BKD) among two year classes of farmed Atlantic salmon,Salmo salar L., in New Brunswick, Canada. (Submitted to Aquaculture)

3. Daoud D., C. Dubetz & Barker DE. 2018. Effects of emamectin benzoate or ivermectin in sediments on juvenile American lobsters (Homarusamericanus). Ecotox. Environ. Safety 163: 636-646.

4. Barker DE & SM Robinson. 2017. Mucus antibacterial activity and behavioural stress indicators of Atlantic salmon when exposed to a warm (30- 34°C) saltwater shower for treatment of sea lice. Technical report of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 30 pp. Client: Fisheries & Oceans Canada, St. Andrews Biological Station, NB. (Now in prep for submission to Aquaculture.)

5. Barker DE. 2017. Effect of feed withdrawal on fillet concentration of emamectin benzoate in Atlantic salmon after SLICE® dosing. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 26 pp. Client: Merck Animal Health, New Jersey, USA.

6. Barker DE & S Chowdhury. 2017. Toxicity assessment of a novel Saprolegnia therapeutant when applied to Atlantic salmon eggs and fry. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 32 pp. Client: RPS Biologiques, Charlottetown, PE.

7. Barker DE. 2017. Safety assessment of an oxygen gas infusion system used during various H2O2 treatments on Atlantic salmon. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 23 pp. Client: Gas Infusion Systems (GIS), Saint John, NB.

8. Barker DE. 2017. Taxonomic analysis of sea lice recovered from a New Brunswick salmon farm site (ELACA160088) during experimental product (XXXX) trials. (Details withheld due to non-disclosure agreements.) Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 22 pp. Client: Elanco Animal Health, New South Wales, Australia.

9. Barker DE. 2017. Effects of diluted bitumen (dilbit) on ovigerous (berried) female American lobster, Homarus americanus. Technical report (GLP- compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 24 pp. Client: DFO National Contaminants Advisory Group (NCAG), Ottawa, ON. (Currently in prep for submission to Ecotoxicology and Environmental Safety)

10. Barker DE. 2016. Effects of diluted bitumen (dilbit) on early life stages of Atlantic salmon, Salmo salar. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 32 pp. Client: DFO National Contaminants Advisory Group (NCAG), Ottawa, ON. (Currently in prep for submission to Ecotoxicology and Environmental Safety)

11. Barker DE. 2016. Evaluation of recent low weir catches of herring (Clupea harengus) in New Brunswick. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 27 pp. Client: KCR Fisheries (Connors Brothers), NB.

12. Barker DE. 2016. Pilot study to assess efficacy of a novel compound against Saprolegnia sp. infections on Atlantic salmon (Salmo salar) eggs using in-vitro models. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 38 pp. Client: RPS Biologiques, Charlottetown, PE.

13. Barker DE. 2016a. Taxonomic analysis of sea lice recovered from a New Brunswick salmon farm site (Sponsor Study Number NAH-13-071) during experimental product (XX) trials. (Details withheld due to non-disclosure agreements.) Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 65 pp. Client: Elanco Animal Health, New South Wales, Australia.

14. Barker DE. 2016b. Taxonomic analysis of sea lice recovered from a New Brunswick salmon farm site (Sponsor Study Number NAH-15-014) during experimental product (XX) trials. (Details withheld due to non-disclosure agreements.) Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 48 pp. Client: Elanco Animal Health, New South Wales, Australia.

15. Barker DE. 2016c. Taxonomic analysis of sea lice recovered from a New Brunswick salmon farm site (Sponsor Study Number NAH-15-012) during experimental product (XX) trials. (Details withheld due to non-disclosure agreements.) Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 61 pp. Client: Elanco Animal Health, New South Wales, Australia.

16. Barker DE. 2016. Assessing tank configuration and stocking density on green sea urchin (Strongylocentrotus droebachiensis) system maintenance, survival, stress and gonad enhancement. Technical report (GLP-compliant) of the Aquatic Services Department, Huntsman Marine Sciences Centre. St. Andrews, NB. 48 pp. Client: Quoddy Savour Seafoods, Shippagan, NB.

17. Novak C, D Lewis, B Collicutt, K Verkaik & DE Barker. 2016. Investigations on the role of the salmon louse Lepeophtheirus salmonis (Caligidae) as a vector in the transmission of Aeromonas salmonicida. J Fish Dis 39: 1165-1178, doi:10.1111/jfd.12449.

18. Braden LM, DE Barker; BF Koop & SRM Jones. 2015. Differential modulation of resistance biomarkers in skin of juvenile and mature pink salmon, Oncorhynchus gorbuscha by the salmon louse, Lepeophtheirus salmonis. Fish Shellfish Immunol DOI: 10.1016/j.fsi.2015.08.008.

19. Lewis, D, DE Barker, RS McKinley. 2014. Modulation of cellular innate immunity by Lepeophtheirus salmonis secretory products. (Fish Shellfish Immunol 38:175-183).

20. Braden LM, DE Barker, B Koop & SRM Jones. 2012. Comparative defense-associated responses in salmon skin elicited by the ectoparasite Lepeophtheirus salmonis. Comp Biochem Physiol D, 7: 100-109. doi:10.1016/j.cbd.2011.12.002.

21. Jakob E, DE Barker & K Garver. 2011. Vector potential of the salmon louse (Lepeophtheirus salmonis) in the transmission of infectious hematopoietic necrosis virus (IHNV). Dis Aquat Org. 97(2):155-65.

22. Novak C, DE Barker & RS McKinley. 2011. First report of Lepeophtheirus salmonis (Copepoda: Caligidae) as a potential vector of Aeromonas salmonicida. Aqua Assoc Can Spec Pub 20:84-87.

23. DE Barker & J Halliday. 2010 Blood lymphocyte and neutrophil response of cultured rainbow trout, Oncorhynchus mykiss, administered varying dosages of the Cordyceps-derived, oral immunomodulator, Fin-ImmuneTM. Int J Med Mushr 12:185-192.

24. Barker DE, LM Braden, MP Coombs & B Boyce. 2009. Preliminary studies on the isolation of bacteria from sea lice, Lepeophtheirus salmonis, infecting farmed salmon in British Columbia, Canada. Parasitol Res 105: 1173-1177.

25. Barker DE, LM Braden, MP Coombs & B Boyce. 2008. Little bugs with smaller bugs: preliminary studies on the role of sea lice as a vector of bacterial pathogens. Aqua Assoc Can Spec Pub 14: 20-23.

26. Soko CK & DE Barker. 2005. Efficacy of crushed garlic and lemon juice as bio-product treatments for Ichthyophthirius multifiliis (‘ich’) infections among cultured, juvenile Nile tilapia, Oreochromis niloticus. Aqua Assoc Can Spec Pub 9: 108-110.

27. Jenkins C & DE Barker. 2005. The efficacy of oral immunostimulants in enhancing resistance against Microsporidiosis in juvenile Atlantic cod (Gadus morhua L.) Aqua Assoc Can Spec Pub 9: 97-100.

28. Arthur JR, DK Cone, R Cusack, DE Barker & MDB Burt. 2004. Two species of Trichodina (Ciliophora: Peritrichida) from cultured flatfishes (Pleuronectiformes) in Atlantic Canada. Comp Parasit 71(2): 247-250.

29. Barker DE & J Davis. 2004. Preliminary testing of oral immunostimulants against Microsporidiosis in cultured cod (Gadus morhua). Aqua Assoc Can Spec Pub 8:20-26.

30. Barker DE 2004. Optimal Dosage, Safety Margin and Shelf-life of the Anaesthetic, Benzocaine, for Cultured Atlantic Salmon (Salmo salar) and Rainbow Trout (Oncorhynchus mykiss). Technical report of the Centre for Aquaculture and Seafood Development, Marine Institute of Memorial University. St. John’s, NL. 18 pp.

31. Barker DE, AM MacKinnon, L Boston, DK Cone, MDB Burt, S Griffiths, DJ Speare, M Cook, R Ritchie & G Olivier. 2002a. First report of piscine Nodavirus infecting wild winter flounder, in Passamaquoddy Bay, New Brunswick, Canada. Dis Aquat Org 49: 99-105.

32. Barker DE 2002a. Screening for Microsporidian Infections among Sea-caged, Hatchery Cod and Wild Fish. Technical report of the Centre for Aquaculture and Seafood Development, Marine Institute of Memorial University. St. John’s, NL. 14 pp.

33. Barker DE 2002b. Monitoring Parasites and Pathogens of Cod Aquaculture. Technical report of the Centre for Aquaculture and Seafood Development, Marine Institute of Memorial University. Marine Institute of Memorial University, St. John’s, NL. 41 pp.

34. Barker DE 2002c. Efficacy of Oral Immunostimulants Added to a Commercial Feed for Cod: a Pilot Study. Technical report of the Centre for Aquaculture and Seafood Development, Marine Institute of Memorial University. 15 pp.

35. Barker DE 2002d. Evaluation of Microsporidian Infections among Sea-caged, Hatchery Cod During Summer in Hermitage Bay. Technical report of the Centre for Aquaculture and Seafood Development, Marine Institute of Memorial University. St. John’s, NL. 10 pp.

36. Barker DE, DK Cone & MDB Burt. 2002b. Trichodina murmanica (Ciliophora) and Gyrodactylus pleuronecti (Monogenea) parasitizing hatchery- reared juvenile winter flounder: effects on host growth and assessment of parasite interaction. J Fish Dis 25:81-89.

37. Barker DE & DK Cone. 2000. Occurrence of Ergasilus celestis (Copepoda) and Pseudodactylogyrus anguillae (Monogenea) among wild eel, Anguilla rostrata, in relation to stream flow, pH and temperature and recommendations for controlling their transmission among captive eels. Aquaculture 187: 261-274.

38. Mercer IRG, DE Barker & RA Khan. 1997. Stress-related changes in the cunner, Tautogolabrus adspersus, living near a paper mill. Bull Environ Contam Toxicol 58: 442-447.

39. Barker DE, DJ Marcogliese and DK Cone. 1996. On the distribution and abundance of eel parasites in Nova Scotia: local versus regional patterns. J Parasit 82: 697-701.

40. Khan RA, DE Barker, K Williams-Ryan, B Murphy & RG Hooper. 1996. Abnormalities in winter flounder (Pleuronectes americanus) living near a pulp and paper mill in the Humber Arm, Newfoundland. In: Environmental Fate and Effects of Pulp and Paper Mill Effluents. Eds. M.R. Servos, K.R. Munkittrick, J.H.Carey and G. VanderKraak. St. Luce, Florida. pp. 511-523.

41. Barker DE, RA Khan & RG Hooper. 1994. Bioindicators of stress in winter flounder, Pleuronectes americanus, captured adjacent to a pulp and paper mill in St. George's Bay, Newfoundland. Can J Fish Aquat Sci. 51(10): 2203-2209.

42. Barker DE, RA Khan, EM Lee, RG Hooper & K Ryan.1994. Anomalies in sculpins (Myoxocephalus spp.) sampled near a pulp and paper mill. Arch Environ Contam Toxicol 26: 491-496.

43. Khan RA, DE Barker, RG Hooper, EM Lee, K Ryan and K Nag.1994. Histopathology in winter flounder (Pleuronectes americanus) living adjacent to a pulp and paper mill. Arch Environ Contam Toxicol 26: 95-102.

44. Khan RA, DE Barker, K Williams-Ryan & RG Hooper. 1994. Influence of crude oil and pulp and paper mill effluent on mixed infections of Trichodina cottidarium and T. saintjohnsi (Ciliophora) parasitizing Myoxocephalus octodecimspinosus and M. scorpius. Can J Zool 72: 247-251.