THE BREEDIPTC O F THE NORTII ATLANTIC FRESHWATER-EELS
141
Altogether I find that Schmidt had very good reasons for assuming
two breeding populations of the North Atlantic eels, whether they be
called two distinct species ur geographical races. He made these investigations before he knew the location of the breeding places, but it
explained to him why he had failed in finding any eaxly larval stages of
A . anguilla in the Mediterranean on his two expeditions 1908-1910.
111. THE DISTANCE TO COVER DURING THE MIGRATIQN
The ceiitral arc:& for the distribution of’ A . anguilla is the British
Jsles and tlic coasts of tho Buy of I
$0 Tuckcr (1!15!h, p. 4!)(i) is corrcct in giviiig the distance Sor this area
from the breeding places as at lcast 3500 miles on a great circle course.
But in his argument against Jones (1939, p. 1281), who thinks that
A . anguilla is able to cover this distance, he ovcrlooks the fact that the
Azores have a population, about which Schmidt (1909, p. 139) had the
information that A . anguilla is common in all the islands. This reduces
the distance to cover for the eel of the Azores to about 2000 miles, or no
more than A . rostrata from the New England states and Canada have
to cover.
As is known (Bruun, 1937, p. 26), a single A . rostrata has been found
in northern Spain; it was found among several hundred A . anguilla of
which the number of vertebrae were counted. Rather a few specimens
only of eel from the Azores have been examined, altogether 131
(Schmidt, 1913, p. 11) and they were all A . angzcilla. It would, in fact,
be very interesting to have several hunclreds examined to we whether
A . m.stmta might rr:ach thc: AzrmH morc: oflw t h i hiIh!rto wijqjowc~.
Tucker (1‘359a, p. 495) in rcferrirrg to Vaillatrt, I &!)4) rwrirrtnitui h h f ,
“Anguilla adults have yet to he takc:ri in t h : o p r r f w w i ( ( t i i t : firm Lhc
stomach of a cadidot off thc Awrw i H O/JVkJll!ilJ’ wJfiltccl, o f JocnJ
~ ) r o v ~ ! i i ~ ~ i i ~ ( ! ) . ”
11, rnny w r y w d I 1 ) ~ of Iocd provonamw, hut it in
rivvwt I i ( * I ( w [)roof f A i d 8 t~ r.iI)oriiiig 001 IIILH 1 ~ w
ol”-mcd in tho opon
occaii, over vvry t1cc-j) wnlvr, whore tho qwnnwhalo is hunting other
fuwt-swimming crcatirrw like tho sqiritl~ (Clarke, 1058).
If wc sul)1)osc that tlirrc i N ono Hiiiglo : m m t r d species of Anguilla in
the North Atlantic and that this has a distribution more or less like
that which A . rostruta now has, then the North Atlantic islands, first the
Azores, and later on Madeira and the Canaries, may very well have
served as stepping stones towards the development of A . anguilkz;
Jones (1959, p. 1281) is therefore right in assuming “ intense selection
in favour of eels which found the ‘ right ’ spawning ground.” Such
141
Altogether I find that Schmidt had very good reasons for assuming
two breeding populations of the North Atlantic eels, whether they be
called two distinct species ur geographical races. He made these investigations before he knew the location of the breeding places, but it
explained to him why he had failed in finding any eaxly larval stages of
A . anguilla in the Mediterranean on his two expeditions 1908-1910.
111. THE DISTANCE TO COVER DURING THE MIGRATIQN
The ceiitral arc:& for the distribution of’ A . anguilla is the British
Jsles and tlic coasts of tho Buy of I
$0 Tuckcr (1!15!h, p. 4!)(i) is corrcct in giviiig the distance Sor this area
from the breeding places as at lcast 3500 miles on a great circle course.
But in his argument against Jones (1939, p. 1281), who thinks that
A . anguilla is able to cover this distance, he ovcrlooks the fact that the
Azores have a population, about which Schmidt (1909, p. 139) had the
information that A . anguilla is common in all the islands. This reduces
the distance to cover for the eel of the Azores to about 2000 miles, or no
more than A . rostrata from the New England states and Canada have
to cover.
As is known (Bruun, 1937, p. 26), a single A . rostrata has been found
in northern Spain; it was found among several hundred A . anguilla of
which the number of vertebrae were counted. Rather a few specimens
only of eel from the Azores have been examined, altogether 131
(Schmidt, 1913, p. 11) and they were all A . angzcilla. It would, in fact,
be very interesting to have several hunclreds examined to we whether
A . m.stmta might rr:ach thc: AzrmH morc: oflw t h i hiIh!rto wijqjowc~.
Tucker (1‘359a, p. 495) in rcferrirrg to Vaillatrt, I &!)4) rwrirrtnitui h h f ,
“Anguilla adults have yet to he takc:ri in t h : o p r r f w w i ( ( t i i t : firm Lhc
stomach of a cadidot off thc Awrw i H O/JVkJll!ilJ’ wJfiltccl, o f JocnJ
~ ) r o v ~ ! i i ~ ~ i i ~ ( ! ) . ”
11, rnny w r y w d I 1 ) ~ of Iocd provonamw, hut it in
rivvwt I i ( * I ( w [)roof f A i d 8 t~ r.iI)oriiiig 001 IIILH 1 ~ w
ol”-mcd in tho opon
occaii, over vvry t1cc-j) wnlvr, whore tho qwnnwhalo is hunting other
fuwt-swimming crcatirrw like tho sqiritl~ (Clarke, 1058).
If wc sul)1)osc that tlirrc i N ono Hiiiglo : m m t r d species of Anguilla in
the North Atlantic and that this has a distribution more or less like
that which A . rostruta now has, then the North Atlantic islands, first the
Azores, and later on Madeira and the Canaries, may very well have
served as stepping stones towards the development of A . anguilkz;
Jones (1959, p. 1281) is therefore right in assuming “ intense selection
in favour of eels which found the ‘ right ’ spawning ground.” Such