159
3.5.1 Magnetite in Marine Fish
The fi rst experimental results, which confi rm the existence of the magnetic sense in
the elasmobranch fi shes and in salmon, were reported thirty years ago by Kalmijn
( 1982 ) and Quinn ( 1980 ), respectively. The magnetotopotaxis dependent movement
by the sharks and their use of the Earth’s magnetic fi eld for navigation was described
by Klimley ( 1993 ). As suggested by Walker et al. ( 2007 ), “navigating animals might
use the topography of the residual magnetic fi eld to construct a familiar area map,”
(Walker et al. 2007 ). After that, the magnetic material was found in teleosts (Hanson
and Westerberg 1986 ) as well as in such marine fi sh species as Thunnus albacares ,
T. alalunga (Walker et al. 1984 ), Scomber scombrus, Clupea harengus, Sarda sarda
and, in species migrating from brackish to freshwater and back: Oncorhynchus
tschawytscha (Kirschvink et al. 1985b ), O. nerka (Walker et al. 1988 ), O. keta (Yano
et al. 1997 ), Anguilla anguilla , and in species inhabiting inland water bodies:
Cyprinus carpio and Perca fl uviatilis (see for review Formicki et al. 2002 ).
Geomagnetic imprinting by fi sh as they swim away from natal areas has been proposed to generate magnetic preferences used in subsequent return migrations
(Lohmann et al. 2008 ). Thus, magnetically stable SD magnetite particles have been
extracted from the tissue of several fi sh species (Mann et al. 1988 ; Walker et al.
1984 ). These particles closely resemble the ones typically found in magnetotactic
bacteria. In that respect, Walker et al. ( 1997 ) and Diebel et al. ( 2000 ) imaged a candidate magnetoreceptor structure in the basal lamina of the olfactory epithelium in
the rainbow trout, Oncorhynchus mykiss. The candidate magnetoreceptor was interpreted as a chain of SD particles of the same size and shape as bacterial magnetosomes. However, a detailed characterization of the fi ne-structure of the chain and its
connection to the surrounding tissue was not possible. Furthermore, the authors
could only identify one cell containing the candidate magnetoreceptor structure.
This lack of information does not allow for modeling of the functioning of the putative magnetoreceptor mechanism, hence the involvement of these particles in magnetic fi eld perception in the rainbow trout remains as a working hypothesis.
Walker and co-workers ( 1988 ) studied magnetoreception in different life stages
like fry, yearlings and smolts of the sockeye salmon, O. nerka . The authors reported
following results:
• “signifi cant quantities of SD have been localized within magnetite in connective
tissue from the ethmoid region of the skull of adult (4-year-old) animals;
• the ontogenetic study revealed an orderly increase in the amount of magnetic
material in the same region of the skull, but not in other tissues, of sockeye
salmon fry, yearlings and smolts;
• SD magnetite particles suitable for use in magnetoreception are produced
throughout life in the ethmoid region of the skull in O. nerka ;
• there are enough particles present in the skulls of the fry to mediate their
responses to magnetic fi eld direction;
• by the smolt stage, the amount of magnetite present in the front of the skull is
suffi cient to provide the fi sh with a magnetoreceptor capable of detecting small
changes in the intensity of the geomagnetic fi eld,” (Walker et al. 1988 ).
3.5 Biomagnetite in Marine Vertebrates
3.5.1 Magnetite in Marine Fish
The fi rst experimental results, which confi rm the existence of the magnetic sense in
the elasmobranch fi shes and in salmon, were reported thirty years ago by Kalmijn
( 1982 ) and Quinn ( 1980 ), respectively. The magnetotopotaxis dependent movement
by the sharks and their use of the Earth’s magnetic fi eld for navigation was described
by Klimley ( 1993 ). As suggested by Walker et al. ( 2007 ), “navigating animals might
use the topography of the residual magnetic fi eld to construct a familiar area map,”
(Walker et al. 2007 ). After that, the magnetic material was found in teleosts (Hanson
and Westerberg 1986 ) as well as in such marine fi sh species as Thunnus albacares ,
T. alalunga (Walker et al. 1984 ), Scomber scombrus, Clupea harengus, Sarda sarda
and, in species migrating from brackish to freshwater and back: Oncorhynchus
tschawytscha (Kirschvink et al. 1985b ), O. nerka (Walker et al. 1988 ), O. keta (Yano
et al. 1997 ), Anguilla anguilla , and in species inhabiting inland water bodies:
Cyprinus carpio and Perca fl uviatilis (see for review Formicki et al. 2002 ).
Geomagnetic imprinting by fi sh as they swim away from natal areas has been proposed to generate magnetic preferences used in subsequent return migrations
(Lohmann et al. 2008 ). Thus, magnetically stable SD magnetite particles have been
extracted from the tissue of several fi sh species (Mann et al. 1988 ; Walker et al.
1984 ). These particles closely resemble the ones typically found in magnetotactic
bacteria. In that respect, Walker et al. ( 1997 ) and Diebel et al. ( 2000 ) imaged a candidate magnetoreceptor structure in the basal lamina of the olfactory epithelium in
the rainbow trout, Oncorhynchus mykiss. The candidate magnetoreceptor was interpreted as a chain of SD particles of the same size and shape as bacterial magnetosomes. However, a detailed characterization of the fi ne-structure of the chain and its
connection to the surrounding tissue was not possible. Furthermore, the authors
could only identify one cell containing the candidate magnetoreceptor structure.
This lack of information does not allow for modeling of the functioning of the putative magnetoreceptor mechanism, hence the involvement of these particles in magnetic fi eld perception in the rainbow trout remains as a working hypothesis.
Walker and co-workers ( 1988 ) studied magnetoreception in different life stages
like fry, yearlings and smolts of the sockeye salmon, O. nerka . The authors reported
following results:
• “signifi cant quantities of SD have been localized within magnetite in connective
tissue from the ethmoid region of the skull of adult (4-year-old) animals;
• the ontogenetic study revealed an orderly increase in the amount of magnetic
material in the same region of the skull, but not in other tissues, of sockeye
salmon fry, yearlings and smolts;
• SD magnetite particles suitable for use in magnetoreception are produced
throughout life in the ethmoid region of the skull in O. nerka ;
• there are enough particles present in the skulls of the fry to mediate their
responses to magnetic fi eld direction;
• by the smolt stage, the amount of magnetite present in the front of the skull is
suffi cient to provide the fi sh with a magnetoreceptor capable of detecting small
changes in the intensity of the geomagnetic fi eld,” (Walker et al. 1988 ).
3.5 Biomagnetite in Marine Vertebrates