Association between bluefin tuna schools and oceanic features in the western Mediterranean

We present an analysis of the distribution of bluefin tuna Thunnus thynnus schools spot- ted during aerial surveys in the Gulf of Lions, in relation to oceanographic features. Bio-optical and thermal properties of the sea surface derived from high-resolution sensors (AVHRR and SeaWiFS) were studied on a daily basis, and an edge-detection technique was applied to detect frontal zones. Geostatistics and point-process analyses were used to evaluate the role of the environment in struc- turing the spatial pattern of bluefin tuna (BFT). The distribution of schools spotted was strongly non- stationary both in space and time; this is believed to be an effect of the survey design (transect sam- pling) and the influence of transient oceanographic structures (surface fronts and eddies). The empirical variograms indicated a spatial range of the BFT schools at around 40 km, with substantial daily variability. Ripley's K statistic, as well as autocorrelation plots, revealed that the fish schools were clustered over a wider range of scales (from 10 to 80 km), indicating more spatial structure than would be expected from a random process. Finally, BFT school distributions appeared well deter- mined by the oceanic features, except at very small scales ( 40 km), where over-spreading was detected. Dynamical ecological processes, such as foraging, are likely to induce this complex spatial pattern. Possible reasons for the association of tuna with fronts are presented.

[1]  J. M. Mason,et al.  Historical Document: Life History and Fisheries of Atlantic Bluefin Tuna , 2011 .

[2]  Jay M. Ver Hoef,et al.  Spatial Analysis in Ecology , 2006 .

[3]  J. Fromentin.  The East Atlantic and Mediterranean bluefin tuna stock management: uncertainties and alternatives , 2003 .

[4]  Janet Campbell,et al.  Biogeochemical patchiness at the sea surface , 2002 .

[5]  M. R. T. Dale,et al.  Conceptual and mathematical relationships among methods for spatial analysis , 2002 .

[6]  F. Gohin,et al.  A five channel chlorophyll concentration algorithm applied to SeaWiFS data processed by SeaDAS in coastal waters , 2002 .

[7]  J. Fromentin,et al.  Fishing effects and life history traits: a case study comparing tropical versus temperate tunas , 2001 .

[8]  O. Maury,et al.  Hierarchical interpretation of nonlinear relationships linking yellowfin tuna (Thunnus albacares) distribution to the environment in the Atlantic Ocean , 2001 .

[9]  David Sean Kirby,et al.  A dynamic optimisation model for the behaviour of tunas at ocean fronts , 2000 .

[10]  A. Baddeley,et al.  Non‐ and semi‐parametric estimation of interaction in inhomogeneous point patterns , 2000 .

[11]  F. Menczer,et al.  Co-evolution of movement behaviours by tropical pelagic predatory fishes in response to prey environment: a simulation model , 2000 .

[12]  Richard W. Brill,et al.  Tracking adult North Atlantic bluefin tuna (Thunnus thynnus) in the northwestern Atlantic using ultrasonic telemetry , 2000 .

[13]  Ross Vennell,et al.  A front-following algorithm for AVHRR SST imagery , 2000 .

[14]  Peter Cornillon,et al.  Satellite-derived sea surface temperature fronts on the continental shelf off the northeast U.S. coast , 1999 .

[15]  K. Bigelow,et al.  Environmental effects on swordfish and blue shark catch rates in the US North Pacific longline fishery , 1999 .

[16]  Barbara A. Block,et al.  Horizontal movements and depth distribution of large adult yellowfin tuna (Thunnus albacares) near the Hawaiian Islands, recorded using ultrasonic telemetry: implications for the physiological ecology of pelagic fishes , 1999 .

[17]  G. F.,et al.  From individuals to aggregations: the interplay between behavior and physics. , 1999, Journal of theoretical biology.

[18]  A. Longhurst.  Ecological Geography of the Sea , 1998 .

[19]  Patrick Marsaleix,et al.  The plume of the Rhone: numerical simulation and remote sensing , 1997 .

[20]  Ross Ihaka,et al.  Gentleman R: R: A language for data analysis and graphics , 1996 .

[21]  Peter Cornillon,et al.  Multi-Image Edge Detection for SST Images , 1995 .

[22]  S. Chiswell.  Variability in sea surface temperature around New Zealand from AVHRR images , 1994 .

[23]  James J. Simpson,et al.  On the accurate detection and enhancement of oceanic features observed in satellite data , 1990 .

[24]  J. Steele.  The ocean ‘landscape’ , 1989, Landscape Ecology.

[25]  P. Fiedler,et al.  Tuna aggregation and feeding near fronts observed in satellite imagery , 1987 .

[26]  Paul C. Fiedler,et al.  Albacore tuna catch distributions relative to environmental features observed from satellites , 1984 .

[27]  J. Besag.  Efficiency of pseudolikelihood estimation for simple Gaussian fields , 1977 .

[28]  B. Ripley.  The second-order analysis of stationary point processes , 1976, Journal of Applied Probability.

[29]  J. Besag.  Statistical Analysis of Non-Lattice Data , 1975 .

[30]  Jean-Marc Fromentin,et al.  REPORT OF THE 2002 ATLANTIC BLUEFIN TUNA STOCK ASSESSMENT SESSION , 2003 .

[31]  J. Fromentin,et al.  Long-term fluctuations in the eastern Atlantic and Mediterranean bluefin tuna population , 2001 .

[32]  J. Manning,et al.  Tidal-front entrainment and retention of fish larvae on the southern flank of Georges Bank , 2001 .

[33]  J. Keen,et al.  Movements and Temperature Preferences of Atlantic Bluefin Tuna (Thunnus thynnus) off North Carolina: A Comparison of Acoustic, Archival and Pop-Up Satellite Tags , 2001 .

[34]  P. Miller.  Multispectral Front Maps for auto-detection of ocean colour features from SeaWiFS & MODIS , 2000 .

[35]  M. Lutcavage,et al.  The feasibility of direct photographic assessment of giant bluefin tuna, Thunnus thynnus, in New England waters , 1996 .

[36]  A. Bakun.  Patterns in the ocean: Ocean processes and marine population dynamics , 1996 .

[37]  Donald B. Olson,et al.  Life on the edge : marine life and fronts , 1994 .

[38]  B. Hambly.  Fractals, random shapes, and point fields , 1994 .

[39]  Peter J. Diggle,et al.  Statistical analysis of spatial point patterns , 1983 .

[40]  James L. Mueller,et al.  Color and temperature signatures of ocean fronts observed with the Nimbus-7 CZCS , 1981 .

[41]  H. Farrugio.  Exploitation et dynamique des populations de thon rouge Thunnus thynnus (Linné, 1758) atlanto méditerranéennes , 1981 .

[42]  B. Ripley.  Modelling Spatial Patterns , 1977 .

[43]  F. James Rohlf,et al.  Biometry: The Principles and Practice of Statistics in Biological Research , 1969 .

[44]  D. Myers,et al.  Ecography 25: 558 -- 577, 2002 , 2022 .

[45]  M. Armenteros,et al.  Digital Commons @ University of Digital Commons @ University of South Florida South Florida , 2022 .