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Fishery Bulletin 99(4) 
although they reported some heavier but younger speci- 
mens than we found. This difference could be due to dis- 
crepancies in the aging methods or, as in the case of Man- 
gold ( 1983), areas off the coast may have different growth 
patterns and lifespans. Thus, Smale and Buchan (1981) 
proposed a lifespan of 9-12 months in females and 12-15 
in males Octopus vulgaris from the South African coast. 
Several authors have noted that size (and probably 
weight) may not reliably indicate age in field-caught ceph- 
alopods (Mangold and Boletzky, 1973; Hixon, 1980) be- 
cause it may vary greatly depending upon factors such 
as food and temperature (Van Heukelem, 1979; Mangold, 
1983). Cephalopods reveal great morphological variability 
with latitude attributed to environmental influences on 
development ( Hernandez-Garcia and Castro, 1998), and 
probably on lifespan. The length and weight ranges of oc- 
topus caught off the Canary Islands are within the ranges 
reported for this species off East Africa, are the limits of 
range (upper and lower) off South Africa (Smale and Bu- 
chan, 1981) and in the western Mediterranean Sea (Man- 
gold, 1983), although the range recorded in our study 
(Canary Islands) is closer to that reported for the Mediter- 
ranean Sea. 
The smallest octopi that we examined from fishery 
catches were 4.8 and 8.1 mm VML (0.38 and 0.60 g TW, re- 
spectively), well outside the minimum commercial length 
(90-100 mm VML). Their estimated ages were 51 and 91 
days old. In the English Channel, the planktonic phase for 
common octopus has been estimated at 3 months (Rees, 
1950; Rees and Lumby, 1954); and average weight of 0.2 g 
at settling may be normal regardless of temperature (Man- 
gold, 1983). Octopus typically spend the first 5-12 weeks 
of life as an active predator on plankton (Mangold, 1983); 
they change gradually from a planktonic to benthic life 
style (Boletzky, 1977) in some way dependent upon tem- 
perature (Mangold 1983). We did not observe marked dif- 
ferences in ring pattern spacing indicative of the transi- 
tion between planktonic and benthic life styles. However, 
the distance between rings does change during the ben- 
thic phase of life — a feature that seems related to water 
temperature — the rings being larger than average during 
winter and smaller during summer. 
