BODY LENGTH AND BODY WEIGHT OF STENELLA AND DELPHINUS 



817 



is the relative weight of Stenella and Delphinus in the Western Mediterranean 

 increases slower per unit of the relative length than that of the Mysticetes and the 

 Pilot Whale (Fig. 1). 



SUMMARY 



The length-weight relationship of two species of beaked dolphins — Stenella 

 styx Gray and Delphinus delphis L. — from the Western Mediterranean was inves- 

 tigated. The slope of régression line (b) is significant for both species at a signif- 

 icance level of P = 5% and is 2.6104 for Stenella and 2.3569 for Delphinus. 

 The relative weight of Stenella and Delphinus increases slower per unit of the 

 length than that of the Whalebone and Pilot Whale. 



ZUSAMMENFASSUNG 



Bei zwei Arten von Schnabeldelphinen — Stenella styx Gray und Delphinus 

 delphis L. — aus dem westlichen Mittelmeer wurde die Beziehung Kôrperlànge 

 zu Kôrpergewicht untersucht. Der Anstieg der Regressionsgeraden (b) ist fur 

 beide Arten bei einem P = 5 % statistisch gesichert und betràgt fur Stenella 

 2.6104, fur Delphinus 2.3569. Die ermittelten Geraden verlaufen flacher als die 

 der anderen Cetaceen, d.h. dass pro Einheit Kôrperlànge das relative Kôrper- 

 gewicht von Stenella und Delphinus langsamer zunimmt als das der Mysticeten 

 und des Pilotwals. 



ACKNOWLEDGEMENTS 



This paper (XXXIV. Contribution on Cetacea) has been prepared with the 

 aid of the Swiss National Fund for Promotion of Scientific Research (Grant 

 No. 4606) and the C.N.R.S. Paris. We are also indebted to Dr. H. Riedwyl of 

 the Institute for Mathematical Statistics, University of Berne, Switzerland, for the 

 calculating scheme of the régression line. 



LlTERATURE CITED 



Riedwyl, H. Personal communication. 



Schultz, L.P. 1938. Can the weight of whales and large fish be calcidated? J. Mammal., 

 19: 480—487. 



Sergeant, D.E. 1962. The biology of the pilot or pothead whale Globicephala melaena 

 (Traill) in Newfoundland waters. Fish. Res. Board Canada (Ottawa), 

 132: 1-84. 



