The importance of scale to predator-prey spatial correlations: an example of Atlantic fishes

The signs and strengths of spatial correlations between densities of predators and their prey were scale dependent both in simulations and when calculated from acoustic transects across nearshore distributions of Atlantic cod (Gadus morhua), and its prey, capelin (Mallotus villosus). Spectral analyses of 1985 and 1986 transects indicated that spatial correlation (coherence) varied relative to: (1) the occupation of thermal refuge areas by capelin (sea temperatures 8.5°C), (2) the aggregation dimensions of each species, and (3) the activity level of the predator. When capelin did not occupy thermal refuges, cod and capelin densities were coherent across a wide range of scales (2—30 km). At large scales (>4—10 km) densities were in phase (positively correlated), but at scales less than aggregation dimensions (3.5 km), densities were out of phase (negatively correlated). At the smallest scales measured (2—3 km), densities exhibited maximum negative correlation in both years. When capelin were aggr...

[1]  Correlations of predatory whelks with intertidal prey at several scales of space and time , 1988 .

[2]  D. Cushing,et al.  Spatial Distributions and Ecology of Pelagic Fish , 1978 .

[3]  K. Denman,et al.  Spectral Analysis in Ecology , 1975 .

[4]  L. M. Dickie,et al.  An Echo Counting and Logging System (ECOLOG) for Demersal Fish Size Distributions and Densities , 1983 .

[5]  J. Piatt,et al.  Scale-dependent correlation of seabirds with schooling fish in a coastal ecosystem , 1986 .

[6]  T. Quinn.  Line transect estimators for schooling populations , 1985 .

[7]  R. J. Schmitt,et al.  Consequences of Dissimilar Defenses Against Predation in a Subtidal Marine Community , 1982 .

[8]  W. C. Leggett,et al.  Interactive Effects of Geophysically-Forced Sea Temperatures and Prey Abundance on Mesoscale Coastal Distributions of a Marine Predator, Atlantic Cod (Gadus morhua) , 1989 .

[9]  P. Fairweather,et al.  Preliminary investigations of predation by the whelk Morula marginalba , 1984 .

[10]  Anthony L Bertapelle.  Spectral Analysis of Time Series. , 1979 .

[11]  W. Templeman.  Some instances of cod and haddock behaviour and concentrations in the Newfoundland and Labrador areas in relation to food , 1965 .

[12]  G. Seber,et al.  The Estimation of Animal Abundance , 1975 .

[13]  W. C. Leggett,et al.  Atmosphere–Ocean Coupling and Atlantic Cod Migrations: Effect of Wind-Forced Variations in Sea Temperatures and Currents or Nearshore Distributions and Catch Rates of Gadus morhua , 1988 .

[14]  D. G. Watts,et al.  Spectral analysis and its applications , 1968 .

[15]  D. J. Strauss,et al.  The Estimation of Animal Abundance. , 1974 .

[16]  K. Frank,et al.  Reciprocal Oscillations in Densities of Larval Fish and Potential Predators: A Reflection of Present or Past Predation? , 1985 .

[17]  J. Magnuson,et al.  Characterization of Patches Along Transects Using High-Resolution 70-kHz Integrated Acoustic Data , 1989 .

[18]  W. C. Leggett,et al.  Hydroacoustic Signal Classification of Fish Schools by Species , 1988 .

[19]  G. Fryer.  Enemy-free space: a new name for an ancient ecological concept , 1986 .