Dr. Charles David kindly forwarded to me information about the capture
and release of a new born (neonate) porbeagle shark, Lamna nasus,
over Great Bank off Guernsey's east coast on 2 July 2009. Andy Simon
wrote that the new born shark weighed about 15 lbs. and was about 3 feet
long. It was caught at 4.30 pm out from Fermain Bay. The juvenile
shark was released unharmed. Andy Simon, father of the angler, has
given me permission to share these images with you that were taken on his
mobile phone. One image shows the snout of the shark in the net and
another of the ventral surface. The image of the ventral surface
shows clearly that the yolk sac has not yet been fully absorbed.
This shark was born very recently. Porbeagle sharks usually produce
two young per uterus (four in total per litter) after a long gestation.
The embryos are oophagous. The mother only fertilises two eggs in
each uterus but she produces copious amounts of eggs during gestation,
which the developing embryos eat. The embryos have sharp teeth to
tear the skin of the eggs apart. See below image of four embryos
from a Guernsey caught porbeagle shark. The developing embryos have
a large abdominal yolk sac, which they absorb during development.
During the colder months Guernsey fishermen catch porbeagle sharks occasionally.
The captured adult females usually carry embryos. It appears that
Channel Island waters are a nursery ground for porbeagle sharks as there
is evidence that porbeagle sharks give birth here. For
a while Guernsey held the world angling record for a porbeagle shark. Des
Bougourd caught a 430 lb female porbeagle in July 1969 off the Minquiers
south of Jersey. The fishing boat, Storm Drift, was based in Guernsey
so the record was attributed to Guernsey. Des Bougourd's shark contained
four near-term embryos weighing 16 1/2 lbs, 15 1/4 lbs, 14 3/4 lbs and
14 1/4 lbs - weighing collectively 60 3/4 lbs, which is probably what made
the porbeagle shark capture an angling record. See
have been many large porbeagle sharks caught in Guernsey waters in recent
years. See http://homepage.mac.com/mollet/Ln/Ln_large.htmlIn
1999 there was a frenzy in the UK media about a possible sighting of a
great white shark off the coast of Cornwall. Several anglers searched
Guernsey waters for it. Subsequently an image appeared on the front
page of The Guernsey Press with an angler and his capture of a new born
porbeagle shark (mis-identified as a blue shark.) For
information of porbeagle shark litters from Channel Island waters see http://homepage.mac.com/mollet/Ln/Ln_litter.html
information from IUCN website:
porbeagle reaches a maximum reported size of 355 cm TL (Francis et al.
in press). Males mature at about 165 cm TL in the South Pacific and 195
cm TL in theNorth
Females mature at about 195 cm TL in the South Pacific and 245 cm TL in
et al. 2002, Francis and Duffy 2005, Francis et al. in press).
is oophagous with litters of 1 to 5 pups (average four) produced, which
are 68 to 78 cm TL at birth (Compagno 1984a, Gauld 1989, DFO 2001a, Francis
and Stevens 2000, Francis et al. in press). Aasen (1963) estimated that
the gestation period was about eight months in theNorth
that individual females breed each year. However, Shann (1923) found two
distinct size groups of embryos present in the December to February period
and suggested that gestation may last 18 to 24 months. Gauld (1989) noted
that a resting period may be present between parturition and fertilisation.
Francis and Stevens (2000), Jensen et al. (2002) and Francis et al. (in
press) estimate an 8 to 9 month gestation period. Birth occurs in spring
off Europe, spring-summer off North America and winter in Australasia (Aasen
1963, Francis and Stevens 2000, Jensen et al. 2002) and the Eastern Pacific
et al. unpublished data)."
Simon image showing neonate porbeagle shark (approx. 15 lbs.) with atrophied
porbeagle embryos from a Guernsey caught porbeagle shark.