SPERM WHALE DISTRIBUTIONS AND COMMUNITY ECOLOGY ASSOCIATED WITH A WARM‐CORE RING OFF GEORGES BANK

Sperm whale (Physeter macrocephalus) sighting rate in the vicinity of a thermal front on the eastern boundary of a Gulf Stream warm-core ring was five times greater than the pooled rate in the remainder of the study area. No sperm whales were sighted within the ring away from frontal boundaries. Sperm whale distribution patterns associated with the ring were examined using hydrographic and zooplankton data. Hydrographic structure and zooplankton densities and community composition differed between the high-use region and the remainder of the study area, suggesting that mesoscale patterns in the biological and physical environments regulate sperm whale habitat usage. Satellite thermal images indicated cool water associated with the eastern front was shelf or slope water entrained from the Scotian Shelf to the north. Interaction of the warm-core ring with the shelf or slope water is probably indirectly responsible for greater sperm whale presence on the eastern boundary of the ring, providing suitable habitat for their squid prey. Entrainment of shelf water by warm-core rings occurs frequently, providing potential sperm whale habitat in the vicinity of rings. Surveys of warm-core rings and other Gulf Stream features are needed to improve accuracy of sperm whale population estimates.

[1]  G. García-Moliner,et al.  Variability in pigment concentration in warm‐core rings as determined by coastal zone color scanner satellite imagery from the Mid‐Atlantic Bight , 1994 .

[2]  H. Whitehead,et al.  Scale-dependent correlation of sperm whale distribution with environmental features and productivity in the South Pacific , 1996 .

[3]  RELATIVE ABUNDANCE, DISTRIBUTION AND INTER-SPECIFIC RELATIONSHIP OF CETACEAN SCHOOLS IN THE EASTERN TROPICAL PACIFIC , 1987 .

[4]  D. Olson.  Lateral exchange within Gulf stream warm-core ring surface layers , 1986 .

[5]  T. Linkowski,et al.  Food of the squidOmmastrephes bartramii(Lesueur, 1821) from the South-West Atlantic Ocean , 1988 .

[6]  Peter Cornillon,et al.  Gulf Stream warm rings: a statistical study of their behavior , 1986 .

[7]  Yu. M. Froerman.  Feeding Spectrum and Trophic Relationships of Short-finned Squid (II/ex illecebrosus) in the Northwest Atlantic* , 1983 .

[8]  Distribution and behaviour of male sperm whales on the Scotian Shelf, Canada , 1992 .

[9]  I. Aoki,et al.  Acoustic observations of fish schools and scattering layers in a Kuroshio warm-core ring and its environs , 1992 .

[10]  H. Whitehead,et al.  Coherence between 19th century sperm whale distributions and satellite-derived pigments in the tropical Pacific , 1996 .

[11]  G. Waring,et al.  U.S. Atlantic and Gulf of Mexico marine mammal stock assessments--2002 , 1995 .

[12]  David L. Evans,et al.  Shelf water entrainment by Gulf Stream warm-core rings , 1987 .

[13]  C. M. Ruhsam,et al.  Sperm whales associated with Gulf Stream features off the north‐eastern USA shelf , 1993 .

[14]  Karen S. Baker,et al.  Chronology of warm-core ring 82B , 1985 .

[15]  D. Viale.  Une méthode synoptique de recherche des zones productives en mer : détection simultanée des cétacés, des fronts thermiques et des biomasses sous-jacentes , 1991 .

[16]  D. Olson,et al.  The concentrating of organisms at fronts: a cold-water fish and a warm-core Gulf Stream ring , 1985 .

[17]  R. O'dor.  Big squid in big currents , 1992 .

[18]  S. Nishizawa,et al.  Small-scale zooplankton aggregations at the front of a Kuroshio warm-core ring , 1986 .

[19]  J. Cullen,et al.  Food of the squid Nototodarus gouldi in Bass Strait , 1983 .

[20]  N. E. Brunetti,et al.  Distribution and abundance of early life stages of squid (Illex argentinus) in the south-west Atlantic , 1992 .

[21]  Sb Brandt.  Effects of a Warm-Core Eddy on Fish Distributions in the Tasman Sea of East Australia , 1981 .

[22]  M. Okiyama,et al.  Squid as Predators on Krill (Euphausia superba) and Prey for Sperm Whales in the Southern Ocean , 1988 .

[23]  T. Hopkins,et al.  Species composition and food habits of the micronektonic cephalopod assemblage in the Eastern Gulf of Mexico , 1991 .

[24]  F. Griffiths,et al.  Distribution of mesopelagic decapod Crustacea in and around a warm-core eddy in the Tasman Sea , 1983 .

[25]  J. Wroblewski,et al.  Ichthyoplankton Associated with a Warm Core Ring off the Scotiars Shelf , 1984 .

[26]  T. Joyce,et al.  An upper ocean current jet and internal waves in a Gulf Stream warm core ring , 1984 .