Environmental Engineering Reference
In-Depth Information
Fig. 3.7
Historical
distribution of four
locally extinct skates in
the northwest and
northeast Atlantic: (a)
barndoor skate
Dipturus
laevis
; (b) common
skate
D. batis
; (c) white
skate
Rostroraja alba
;
(d) long-nose skate
D.
oxyrhinchus
. Key: e,
area of local extinction;
p, present in recent
fi sheries surveys; ?, no
knowledge of status; e?,
possible local extinc-
tion. (e) Frequency
distribution of skate
body size - the four
locally extinct species
are black. (After Dulvy
& Reynolds, 2002.)
(a)
(b)
80
°
W
60
°
W
0
°
20
°
E
p
E. USA &
Canada
?
50
°
N
e
e
e
p
e
60
°
N
p
e
e
e
e
p
e
p
40
°
N
?
W. Europe
p
e
50
°
N
e
30
°
N
40
°
N
e
?
(c)
(d)
0
°
20
°
E
0
°
20
°
E
?
?
60
°
N
60
N
e
°
?
?
W. Europe
e
50
°
N
50
°
N
e
W. Europe
?
40
°
N
e?
40
°
N
?
20
(e)
10
0
0
50
100
150
200
250
300
Body size (cm)
Within the sharks and skates, then, it is the
K
-strategists that are most vulnerable
to overexploitation. King and McFarland (2003) provide a broader perspective in
their analysis of life-history traits of a diverse array of marine fi sh (42 species) that
includes skates and sharks. Now we see all skates and sharks as relatively
K
-selected,
being among the largest of fi sh and showing a high degree of parental investment.
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