THE CENTRAL NORTH SEA - A POSSIBLE BREEDING LOCALITY FOR THE COMMON PORPOISE - PHOCOENA PHOCOENA LINNAEUS PETER QUINN
I noted (Quinn, 1983) the stranding of a newly born Common porpoise a Easton Broad beach in 1982. Another calf of this species was discovered during 1983 on Minsmere beach by pupils of Lothingland Middle School. Details of strandings: Locality Date Sex Weight (kg) Length as found (cm) presumed actual (cm) Backfinto tail (cm) Fluke width (cm) Flipper length (cm) Backfin height (cm) Breadth of scapula (cm)
Calf A Easton (TM 520796) 1.8.82.
male 3.2 62 75 35.5 21 13 7 5.4
Calf B Minsmere (TM 478668) 12.7.83. female 3.8 74 76 34
18 12 6
Calf B was substantialy more complete than A. In both animals the individual vertebrae were not fully ossified. They had obviously been born a very short period before stranding and their dimensions suggest death at or shortly after parturition. The calf A had been dead about two weeks at mos whilst calf B seemed in slightly fresher condition - suggesting about one week afloat on the sea. These intervals would point to birth occurring in the period early to mid-July. The prevailing residual offshore current is southerly (pers. comm., S Jones, MAFF) and the Meteorological Office (Bracknell) confirmed that prevailing wind conditions for the successive July periods of 1982 and 1983 were easterly and east-north easterly. The calves would presumably have floated quite low in the water but would nonetheless have been nudged by combination of southerly currents and prevailing easterlies. It could well be that certain populations of the Common porpoise breed in more central parts of the North Sea than has previously been thought the case.
Reference Quinn, P. (1983). Trans. Suffolk Nat. Soc., 19, 360. Peter Quinn Kelsale Teachers' Centre, Saxmundham IP17 2NU.
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