A tale of two whales

A TALE OF TWO WHALES PETER QUINN

O u r coastline (53 miles) is not particularly n o t e d for t h e n u m b e r of d e a d c e t a c e a n s deposited on it by the tides. T h e r e is, on average, a b o u t o n e s t r a n d e d whale carcase r e p o r t e d biennially. D ü r i n g 1982, h o w e v e r , two whales w e r e cast u p o n t o o u r s h o r e — o n e the largest for 64 years and t h e o t h e r q u i t e possibly t h e smallest ever. M o r e r e m a r k a b l y they were both discovered on the s a m e day (Ist A u g u s t ) and on the s a m e b e a c h at E a s t o n B r o a d s e p a r a t e d by a b o u t 40 m e t r e s of shingle. Grid R e f e r e n c e : 520 796.

T h e larger o n e was an adult M i n k e whale—Balaenoptera acutorostrata L a c e p e d e , variously n a m e d as piked whale, lesser rorqual or herring hog.

This individual had a p p a r e n t l y b e e n noted at C o v e h i t h e (one mile to t h e n o r t h ) on t h e previous day. It had evidently been d e a d for several weeks and m o r e r e s e m b l e d a gargoyle than the sleek pinnacle of marine m a m m a l i a n design it had b e e n in life. A s the p h o t o g r a p h shows it lay on its back tilted o n t o its left flipper and was 'coming apart at the seams' (in a s o m e w h a t smelly fashion).

Measurements, description and identification L e n g t h f r o m snout tip to centre of tail fluke 9.14 m e t r e s (30 feet exactly) length of right flipper 1.2 m e t r e s ( a b o u t 13% of b o d y length).

B l o w h o l e to spout tip 1.3 m e t r e s Tail flukes 3.5 m e t r e s .

Sixty-two t h r o a t grooves were c o u n t e d and these e x t e n d e d d o w n the belly to a point just b e h i n d the tip of t h e flipper. T h e s e are distinctive of the fast-swimming r o r q u a l s a n d are great assets for f e e d i n g , allowing the whale to distend its t h r o a t so as to take in great volumes of water with any c o n t a i n e d plankton.

Its h e a d was characterised by the long, straight and sharply p o i n t e d skull or rostrum ( f r o m which the baleen would have h u n g ) along the c e n t r e of which ran a p r o m i n e n t ridge back t o w a r d s the blow-hole. All its baleen plates or ' w h a l e b o n e ' had fallen o u t , p r e s u m a b l y as it drifted over the N o r t h Sea. T h e s e would have b e e n quite distinctive in terms of simplifying t h e identification of t h e whale which was patently a m e m b e r of the rorqual g r o u p .

A f t e r d e a t h whales u n d e r g o d r a m a t i c changes of colour and this t o o h i n d e r e d identification—areas might b e c o m e d a r k e r or paler. H o w e v e r , t h e flipper coloration most closely r e s e m b l e d that of B. acutorostrata, having a large, c e n t r a l and pale patch or b a n d .

T h e pelvic region t o w a r d s the tailstock was very badly lacerated as if c h u n k s of b l u b b e r had b e e n gouged f r o m the d e a d and floating whale by t h e p r o p e l l e r of a ship. O t h e r w i s e t h e r e were no superficial w o u n d s or injuries and no e c t o p a r a s i t e s such as barnacles or whale lice were a p p a r e n t .

Trans. Suffolk

Nat. Soc. 19

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Background Notes The north east Atlantic Minke population is thought to breed somewhere towards the equator then undertake a migration, west of the British Isles, to Norwegian coastal waters for summer feeding on herring, cod, sand eel, mackerei and planktonic crustaceans. Indeed it is thought that Minke whales increasingly take a larger fraction of available krill in polar waters than in the days when the Blue whale and other large rorquals were more numerous prior to commercial exploitation.

The Minke whale is now the main target of whaling Operations. In the southern hemisphere the Japanese hunt it on a large scale and in their country its meat is something of a luxury item. The International Whaling Commission ( I . W . C . ) imposed a quota for 1982 of 7072 Minke whales to be taken.

Different stocks of the species are exploited also in North Atlantic waters.

In 1980 D e n m a r k took 141, Iceland took 201 and Norway killed 2002 individuals. Their catch limit for the North East Atlantic was reduced in 1982 to 1690 whales. At the time of writing the I . W . C . is still discussing an objection by m a j o r whaling nations to its decision to phase out commercial whaling by the 1985/86 season.

T h e Suffolk specimen may have been a wounded victim of Norwegian whaling Operations but more than likely it died of old age, injury or disease.

We know that several Minke whales were in the southern North Sea during 1982 from other records. O n e eight metre long specimen was stranded on the H u m b e r on the 12th July and another live individual was identified 35 miles out at sea on the same day.

Previous Suffolk records of Balaenoptera acutorostrata are:

Trans. Suffolk Nat. Soc. 19

360 Suffolk Natural History, Vol. 19 1890—at Yarmouth a thirty foot specimen was harassed to death by boatmen.

1891—in the river at Gorleston.

1896—on Gorleston beach.

1911—a carcase washed ashore at Lowestoft.

1911—one washed onto Sizewell beach.

The last Suffolk rorqual was a Fin whale (B. physalus) beached at Aldeburg and Shingle Street in 1918.

The Easton whale was removed on 2nd August and buried at Wangford rubbish tip.

The other stranded cetacean was far smaller yet of equal interest, being a very young Common or Harbour Porpoise - Phocoena phocoena Linnae Description This mammal had been dead for several weeks, itsflanksbore smears of oil and its anterior region seemed to have been nibbled away by various scavangers.

Weight—3.2 kilograms (minus head) Actual length—62 cm Presumed birth length—75 cm Flipper length—13 cm Mid dorsal fin toflukenotch—35.5 cm Dorsal fin height—7 cm Tailfluke width—21 cm sex—male Notes

There are very few records of strandings or sightings of young porpoise and there is still much to be learnt about the areas where breeding of this species occurs even though it is the commonest cetacean occurring in British waters.

Up tili 1980 there had been only seven sightings of porpoise calves. An earlier Suffolk record exists for August 1959 when a calf, with attendant adult, was seen off Minsmere over several days (Trans. Suffolk Nat. Soc 272) by H. E. Axell then the R.S.P.B. Warden. One suspected breeding ground is the Northern North Sea. The Easton calf was of such a diminutive size as to suggest either still-birth or death shortly after parturition. A suckling calf would not survive long if its mother was by any means separated from it. Birth is thought to occur in the period June/July for this species.

It seems pertinent to note also two live records of this whale in Suffolk coastal waters during 1982. On 29th March a Single porpoise was seen in the River Ore near Havergate Island at a time when the river was rieh with Trans. Suffolk Nat. Soc. 19

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herrings (pers. comm. J. Partridge, R . S . P . B . ) . On 30th June I s a w a s c h o o l of four about half a mile off Southwold heading northwards.

Though evidently no longer common, it would appear that P. phocoena is not as rare as our records would suggest.

Acknowledgements My thanks go to the following people: Mr. H. D . Collings who informed me of the stranding, Dr. P. G . H. Evans for informative correspondence, Mr. J. Horwood ( M . A . F . F . Laboratory) for details of catches and quotas for the Minke whale, Mr. and Mrs. M. Marshall who assisted with the measurement of the whales and Mr. M. C. Sheldrick (British Museum Natural History) who examined transparencies and photographs to confirm identification and gave information about other cetacean records.

References Bonner, W . N. (1980). Whales. Blandford. p. 146.

Easton, D . F., Klinowska, M. and Sheldrick, M. C. (1982). A Preliminary Analysis of the British Stranding Records of the H a r b o u r Porpoise. Rep. Int. Whal. Comm. 32,423.

Evans, P. G . H . (1980). Cetaceans in British Waters. Mammal Review 20, 23.

Morley, C. (1932). T h e Mammals of Suffolk. Trans. Suffolk Nat. Soc. 2, 28.

Watson, L. (1981). Sea Guide to Whales of the World. Hutchinson, p. 88.

P. Quinn, B.Sc. Cert. E d . , Kelsale Teachers' Centre, Suffolk IP17 2 N U .

Bat versus Bird At dusk on the evening of 17th August, 1982, Peter Lawson, George Maybury and myself were Walking South at Walberswick on the sleepers that take the public footpath through the reed bed; South East of us the wind p u m p was visible. A s we approached the end of the sleepers we heard a shrill continuous squeaking from above our heads. On looking up we saw a large bat, which we took to be a Noctule Aying at a height of 20 to 25 feet. T h e noise continued and at the time there was no apparent reason for it, but as we watched a bird the size of a sedge warbler dropped f r o m the bat. Falling at first like a stone the bird veered off to its right just before entering the reeds.

It did not r e a p p e a r . T h e bat remained in our view for a short time afterwards but eventually disappeared North towards Walberswick village.

A n d r e w Leverett

Trans. Suffolk Nat. Soc. 19