Fr:	Pelerin
Sp:	Peregrino; Pelegri (Catalunya)
It:	Squalo elefante; Mmistinu (Palermo); Pisci sceccu (Messina); Pesce pappagallo (Salerno); Cagna (Trieste)
Ma:	Gabdoll; Pixxitonnu

Diagnosis

Very large and rather stout shark with gill-slits almost encircling the head; gillrakers present on internal gill-slits; small eyes; pointed snout, sometimes with the rostrum appearing almost curiously misshapen or dorsally curved; vast, cavernous mouth with tiny hooked teeth; triangular dorsal fin that may lose vertical rigidity at apex when mature; second dorsal fin considerably smaller than the first and situated slightly anterior to the anal fin; caudal fin lunate with strong lateral keels on dorsally-depressed, wide peduncle; precaudal pits present.  Pectoral fins relatively long but considerably shorter than head-length when mature.  Colour dark slate-grey, olive-grey or nearly black dorsally; somewhat lighter ventrally but with blotchy and variable demarcation that may not be very distinct.  Likely only to be confused with the superficially similar (in dorsal profile) Carcharodon carcharias when encountered free-swimming at the surface, but otherwise unmistakable; the largest Mediterranean fish.

Size

Maximum attained is claimed at 15.2m but this may be spurious;  most encountered range 3 to 9 metres.  Size at birth unknown; free-swimming specimen of 165cm TL is perhaps indicative of a range between 150 to 170cm.

Status and Distribution

Mediterranean Sea: Rare; seasonal.  Cosmopolitan range in the Western Mediterranean, with seasonal pockets of abundance including the Ligurian Sea and Western Italian coastline (Tyrrhenian Sea); sometimes the Straits of Messina in small groups; Sicilian Channel but apparently rarer  there than Carcharodon;  ranges at least as far south as the Kuriate Island (Monastir, Tunisia) annually but infrequently further souteast to Libya and beyond; occasional in the Adriatic Sea but rarer in extreme North; Balkan  peninsula to Aegean, but not common.

Biology

The only planktophagous shark in Mediterranean waters, the basking shark is typically spotted either singly or in small groups cruising slowly at the surface, with dorsal fin exposed and mouth agape as it filter-feeds by channeling  perhaps some 2000 tons of water per hour.  Although appearing typically sluggish, this powerful shark can undertake short bursts of speed and may even leap out of the water according to some sources, although these might prove to be misidentifications with white sharks.  A coastal pelagic species, the basking shark will range right up to the surfline at beaches or along rocky coasts; it also occurs well offshore over deep water.  Localised movements appear correlated with surface concentrations of plankton and this species appears to return annually to favoured coastal sites where individuals aggregate for feeding (and possibly courtship?), whilst also often displaying pronounced sexual segregation.  The Ligurian Sea is apparently one such rallying locality (and also favoured by endemic Mediterranean fin whales), as are the Straits of Messina during early summer months.   The conspicuous disappearance of these sharks from coastal surface waters during the winter months is of particular interest; some writers have suggested a mass movement to deeper waters and a short-term lifestyle then spent either "hibernating" or cruising in some energy-efficient mode at great depths beyond the continental margins, during which time gill-rakers are shed and replaced; however, only long-term satellite telemetry of these fish will serve to resolve this enigma.  Moreover, the interrelationship of these sharks in European waters is unknown; the size-class of Mediterranean (Italian) examples being predominantly of subadult class.  Genetic analysis and visual tagging of Mediterranean and (for example) Irish Sea basking sharks would be useful in attempting to resolve questions over stock management and conservation in the Northeastern Atlantic.  Basking sharks filter-feed exclusively upon planktonic organisms, including copepods and other minute crustaceans.  Presumed ovoviviparous, but scant data on reproduction with only a single pregnant female reported in the (old) literature and not examined in detail; gestation period assumed long as possibly up to 3.5 years; males possibly mature at 6 to 7 years but methods of vertebral ring calibration require confirmation.