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An Assessment of Atlantic Bluefin Tuna (1994) / Chapter Skim
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Appendix E: Evidence for Mixing Based on Parasites
Pages 139-146

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From page 139...
... hnmatures in He water column usually attach to He skin or gill cavity of the host in response to unknown chemical cues, and Hey migrate to the preferred site (the nasal cavity in the case of Nasicola sp.; Be gill chamber in the case of Elytrophora spy.. Generally speaking, adult parasites of this type do not pass from one host to another.
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From page 140...
... . An alternative explanation, not uncommon in the parasitological literature, is Hat the parasites grow larger because they have more room to do so and that the giant fish repeatedly acquire the parasite each time they pass through water harboring immatures.
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From page 141...
... Filled square (Wheeler and Beverley-Burton, 1987; tended line in Prince Edward Island) and filled circle (Phipps, 1980; fork length of 280 cm, traps in Nova Scotia)
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From page 142...
... Except for age 0, sample sizes from the Mediterranean Sea are too small to allow one to draw any inferences. Age 4 fish from the western Atlantic Ocean are not treated as an anomaly, whereas in the Nasicola sp.
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From page 143...
... 6 8 10 FIGURE E-2 Prevalence of parasites as a function of host age and locale of capture (A, Nasicola sp.; B Elytrophora spy Age 9 on the x-axis actually refers to all fish 9 years or older (i.e., giant fish)
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From page 144...
... as 52; the sum is 68. Walters argued that if the parasites were randomly distributed in a homoge TABLE E-3 Prevalence of Nasicola sp., EIytrophora sp., and both parasites in the same host for western Atlantic bluefin tuna ages 2 to 6.
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From page 145...
... An equally valid explanation is that western bluefin tuna acquire both parasites in the relatively warm waters in the west, that eastern bluefin tuna can acquire both parasites in the relatively warm waters of the east, and that the water temperature that permits acquisition is different for the two parasites. The Walters study does not provide evidence to support mixing.
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Key Terms

  • western atlantic
  • atlantic bluefin
  • mean values
  • giant fish
  • atlantic ocean

  • mediterranean sea
  • host size
  • eastern bluefin
  • western bluefin
  • infested fish

  • giant bluefin
  • nova scotia
  • warm water
  • tuna passing
  • relatively warm

  • prince edward
  • fish return
  • fork length
  • parasite size
  • warm waters

  • western tuna
  • marked change
  • valid explanation
  • thunnus thynnus
  • marked increase

  • equally valid
  • prevalence data
  • migration patterns
  • size increases
  • uninfested fish


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