Spatial Structure and Distribution of Small Pelagic Fish in the Northwestern Mediterranean Sea

Understanding the ecological and anthropogenic drivers of population dynamics requires detailed studies on habitat selection and spatial distribution. Although small pelagic fish aggregate in large shoals and usually exhibit important spatial structure, their dynamics in time and space remain unpredictable and challenging. In the Gulf of Lions (north-western Mediterranean), sardine and anchovy biomasses have declined over the past 5 years causing an important fishery crisis while sprat abundance rose. Applying geostatistical tools on scientific acoustic surveys conducted in the Gulf of Lions, we investigated anchovy, sardine and sprat spatial distributions and structures over 10 years. Our results show that sardines and sprats were more coastal than anchovies. The spatial structure of the three species was fairly stable over time according to variogram outputs, while year-to-year variations in kriged maps highlighted substantial changes in their location. Support for the McCall's basin hypothesis (covariation of both population density and presence area with biomass) was found only in sprats, the most variable of the three species. An innovative method to investigate species collocation at different scales revealed that globally the three species strongly overlap. Although species often co-occurred in terms of presence/absence, their biomass density differed at local scale, suggesting potential interspecific avoidance or different sensitivity to local environmental characteristics. Persistent favourable areas were finally detected, but their environmental characteristics remain to be determined.

[1]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[2]  M. Barangé,et al.  Strategies of space occupation by anchovy and sardine in the southern Benguela: the role of stock size and intra-species competition , 2005 .

[3]  Pierre Petitgas,et al.  Indices for capturing spatial patterns and their evolution in time, with application to European hake (Merluccius merluccius) in the Bay of Biscay , 2007 .

[4]  Jennifer L. Dungan,et al.  A balanced view of scale in spatial statistical analysis , 2002 .

[5]  E. John Simmonds,et al.  Fisheries Acoustics: Theory and Practice , 2005 .

[6]  Alberto García,et al.  Small pelagic fish in the NW Mediterranean Sea: An ecological review , 2007 .

[7]  K. Bailey,et al.  Theory, consequences and evidence of eroding population spatial structure in harvested marine fishes: a review , 2013 .

[8]  Murdoch K. McAllister,et al.  Modelling the effects of establishing a marine reserve for mobile fish species , 2002 .

[9]  J. Navarro,et al.  Ontogenetic and seasonal changes in the feeding habits and trophic levels of two small pelagic fish species , 2012 .

[10]  D. Checkley,et al.  Climate Change and Small Pelagic Fish: Contents , 2009 .

[11]  Pierre Petitgas,et al.  Historical fluctuations in spawning location of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) in the Bay of Biscay during 1967-73 and 2000-2004 , 2007 .

[12]  H. Tournier,et al.  LA REPRODUCTION DE LA SARDINE ET DE L'ANCHOIS DANS LE GOLFE DU LION , 1971 .

[13]  K. Frank,et al.  Abundance-distribution relationships and conservation of exploited marine fishes , 2004 .

[14]  M. Litvak,et al.  Density‐dependent habitat selection and the ideal free distribution in marine fish spatial dynamics: considerations and cautions , 2004 .

[15]  J. Fromentin,et al.  Rapid changes in growth, condition, size and age of small pelagic fish in the Mediterranean , 2014 .

[16]  M. Cardinale,et al.  Fishing through time: population dynamics of plaice (Pleuronectes platessa) in the Kattegat–Skagerrak over a century , 2010, Population Ecology.

[17]  J. Miquel,et al.  Characterizing the potential habitat of European anchovy Engraulis encrasicolus in the Mediterranean Sea, at different life stages , 2013 .

[18]  Astrid Jarre,et al.  Small pelagics in upwelling systems: patterns of interaction and structural changes in "wasp-waist" ecosystems , 2000 .

[19]  N. Bez,et al.  Transitive geostatistics to characterise spatial aggregations with diffuse limits : an application on mackerel ichtyoplankton , 2001 .

[20]  Pierre Petitgas,et al.  Relationships between population spatial occupation and population dynamics , 2006 .

[21]  J. Chilès,et al.  Geostatistics: Modeling Spatial Uncertainty , 1999 .

[22]  M. Dickey‐Collas,et al.  Anchovy population expansion in the North Sea , 2012 .

[23]  C. Gini.  Measurement of Inequality of Incomes , 1921 .

[24]  A. Bertrand,et al.  From small‐scale habitat loopholes to decadal cycles: a habitat‐based hypothesis explaining fluctuation in pelagic fish populations off Peru , 2004 .

[25]  S. Somarakis,et al.  Trophodynamics of anchovy in a non-upwelling system: direct comparison with sardine , 2014 .

[26]  K. Gaston,et al.  Intraspecific abundance–occupancy relationships: case studies of six bird species in Britain , 1999 .

[27]  Kung-Sik Chan,et al.  Non-additive and non-stationary properties in the spatial distribution of a large marine fish population , 2012, Proceedings of the Royal Society B: Biological Sciences.

[28]  S. Wanless,et al.  Evidence of intra-specific competition for food in a pelagic seabird , 2001, Nature.

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

[30]  Thierry Boulinier,et al.  The use of conspecific reproductive success for breeding patch selection in terrestrial migratory species , 1997, Evolutionary Ecology.

[31]  Alec D. MacCall,et al.  Dynamic Geography of Marine Fish Populations , 1990 .

[32]  P. Brehmer,et al.  Fisheries Acoustics: Theory and Practice, 2nd edn , 2006 .

[33]  C. Bishop,et al.  Distribution changes and abundance of northern cod (Gadus morhua), 1981-1993. , 1997 .

[34]  Noël Diner,et al.  MOVIES-B: an acoustic detection description software. Application to shoal species' classification , 1993 .

[35]  Ransom A. Myers,et al.  Was an increase in natural mortality responsible for the collapse off northern cod , 1995 .

[36]  Christopher D. Wilson,et al.  Climate–ocean variability and Pacific hake: A geostatistical modeling approach , 2008 .

[37]  G. Matheron.  Principles of geostatistics , 1963 .

[38]  G. Korres,et al.  The Ocean Response to Low-Frequency Interannual Atmospheric Variability in the Mediterranean Sea. Part II: Empirical Orthogonal Functions Analysis , 2000 .

[39]  J. Fromentin,et al.  Spatio-Temporal Patterns of Key Exploited Marine Species in the Northwestern Mediterranean Sea , 2012, PloS one.

[40]  P. Petitgas,et al.  Pelagic fish stock assessment by acoustic methods at Ifremer , 2010 .

[41]  Stallings,et al.  Density dependence and population regulation in marine fish: a large‐scale, long‐term field manipulation , 2012 .

[42]  P. Petitgas.  Biomass-dependent dynamics of fish spatial distributions characterized by geostatistical aggregation curves , 1998 .

[43]  G. Korres,et al.  The Ocean Response to Low-Frequency Interannual Atmospheric Variability in the Mediterranean Sea. Part I: Sensitivity Experiments and Energy Analysis , 2000 .

[44]  Paul G. Fernandes,et al.  Geostatistics for Estimating Fish Abundance , 2000 .

[45]  Nathan M. Bacheler,et al.  Density-dependent, landscape, and climate effects on spawning distribution of walleye pollock Theragra chalcogramma , 2009 .