scholarly journals Diel variation in the vertical distribution and schooling behaviour of sardine (Sardina pilchardus) off Portugal

2007 ◽  
Vol 64 (5) ◽  
pp. 963-972 ◽  
Author(s):  
Juan Zwolinski ◽  
Alexandre Morais ◽  
Vitor Marques ◽  
Yorgos Stratoudakis ◽  
Paul G. Fernandes
Keyword(s):  
Vertical Distribution ◽  
Small Schools ◽  
Pelagic Fish ◽  
Diel Variation ◽  
Sardina Pilchardus ◽  
Cross Sectional ◽  
Fish Schools ◽  
School Expansion ◽  
Schooling Behaviour ◽  
The Vertical Distribution

Abstract Zwolinski, J., Morais, A., Marques, V., Stratoudakis, Y., and Fernandes, P. G. 2007. Diel variation in the vertical distribution and schooling behaviour of sardine (Sardina pilchardus) off Portugal. – ICES Journal of Marine Science, 64: 963–972. Diel patterns in the schooling behaviour and vertical distribution of pelagic fish schools were studied by examining their echotraces from repeated acoustic survey transects at three inshore sites off the Portuguese coast. At two sites, sardine was the dominant pelagic species, and echotrace characteristics of fish schools were similar to those reported in the literature. At the third site, where there was a multispecies pelagic assemblage that included sardine, there was more variability in several of the school descriptors. At all sites, fish schools expanded after sunset, enlarging their cross-sectional area along the horizontal plane and reducing their mean internal acoustic density, while maintaining their overall mean abundance. Downward migration was rapid (within 1 h) after sunset and simultaneous with school expansion. School-like aggregations with total backscattering similar to daytime schools were present throughout the night, although the proportion of small schools and scattered fish appeared to increase at that time. At dawn, sardine rose back up the water column and rapidly reformed into the typical daytime schools. This pattern of diel vertical migration is opposite to that described for most clupeoids worldwide. The implications of this behaviour on abundance estimation by acoustic monitoring surveys for small pelagic fish are discussed.

scholarly journals ANALYSIS OF THE VERTICAL DISTRIBUTION OF THE ABUNDANCE OF SMALL PELAGIC FISH LARVAE IN THE GULF OF CALIFORNIA USING SUBMARINE VIDEOCAMERAS

2009 ◽  
Vol 24 (2) ◽  
pp. 153
Author(s):  
G. Aceves-Medina ◽  
C. J. Robinson ◽  
R. Palomares-García ◽  
J. Gómez-Gutierrez
Keyword(s):  
Vertical Distribution ◽  
Gulf Of California ◽  
Fish Larvae ◽  
Pelagic Fish ◽  
Small Pelagic Fish ◽  
Sardinops Sagax ◽  
Etrumeus Teres ◽  
Engraulis Mordax ◽  
The Vertical Distribution

Análisis de la distribucion vertical de la abundancia de larvas de peces pelágicos menores en el Golfo de California mediante videocámaras submarinas Se utilizaron dos tipos de videocámaras submarinas para estudiar la distribución y abundancia vertical de larvas de los peces pelágicos menores Engraulis mordax, Etrumeus teres y Sardinops sagax a 1 m de resolución, en una localidad en el norte del Golfo de California con condiciones de calma y alta densidad de sardinas adultas. La mayor abundancia promedio (900 larvas m -1 min -1 ) se encontró inmediatamente arriba de la termoclina (33 m) y la picnoclina (36 m), aparentemente no asociada al máximo de clorofila detectado en superficie, ni a la mayor densidad de peces adultos (10 -20 m). Las observaciones con video permitieron determinar la distribución vertical a una resolución imposible de obtener mediante muestreos con redes; sin embargo, esta es una técnica poco útil en zonas con elevada velocidad de las corrientes.

Diel variation in the vertical distribution of deep-water scattering layers in the Gulf of Mexico

2016 ◽  
Vol 115 ◽  
pp. 91-102 ◽  
Author(s):  
Marta D'Elia ◽  
Joseph D. Warren ◽  
Ivan Rodriguez-Pinto ◽  
Tracey T. Sutton ◽  
April Cook ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Vertical Distribution ◽  
Deep Water ◽  
Diel Variation ◽  
The Vertical Distribution

Diel vertical distribution of fish larvae during the winter-mixing period in the Northwestern Mediterranean

2004 ◽  
Vol 61 (8) ◽  
pp. 1243-1252 ◽  
Author(s):  
A. Sabatés
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Fish Species ◽  
Fish Larvae ◽  
Distribution Patterns ◽  
Diel Variation ◽  
Surface Layers ◽  
Light Levels ◽  
Vertical Distributions ◽  
The Vertical Distribution

Abstract The vertical distributions of the larvae of shelf and oceanic fish species that spawn during the winter-mixing period in the Mediterranean are described from 22 vertically stratified plankton tows. Diel differences in the vertical distribution patterns in relation to physical data and potential prey abundance throughout the water column were examined. Even in absence of stratification, the larvae of the various fish species showed different patterns of vertical distribution and diel changes. The larvae of shelf-dwelling species were found in the surface layers, mainly above 50-m depth, and with some exceptions, with very little diel variation in depth distribution. Therefore, the vertical distribution of the larvae of these species coincided with the maximum concentrations of their potential food, nauplii and copepodite stages of copepods. The larvae of mesopelagic fishes showed deeper distributions in the water column and most of these species were located closer to the surface during the day than at night. Given the homogeneity of the physical characteristics throughout the water column, except for light, this behaviour may be determined not only by the higher concentration of prey in the surface layers but also by adequate light levels for feeding.

scholarly journals Daytime pelagic schooling behaviour and relationships with plankton patch distribution in the Sicily Strait (Mediterranean Sea)

2011 ◽  
Vol 2 (1) ◽  
pp. 79 ◽  
Author(s):  
B. Patti ◽  
A. Bonanno ◽  
M. D'Elia ◽  
E. Quinci ◽  
G. Giacalone ◽  
...  
Keyword(s):  
Water Column ◽  
Pelagic Fish ◽  
Shelf Zone ◽  
Fish Schools ◽  
Plankton Biomass ◽  
Dominant Fish ◽  
Schooling Behaviour ◽  
The Relationship ◽  
Whole Water ◽  
Northern Sector

In this study, hydroacoustic data collected with a scientific echosounder working at two frequencies (38 and 120 kHz) over the continental shelf off the southern Sicilian coast were used in order to investigate the relationship between fish schools and plankton patches. Specifically, image analysis algorithms were applied to raw echograms in order to detect and characterise pelagic fish schools and plankton aggregations, considered as a proxy of food availability. The relationship was first investigated using estimated total plankton biomass over the whole water column and, second, by dividing the study area into three sub-regions and further distinguishing plankton patches between the surface and the bottom. In the relatively lower plankton abundance areas of Zone 1 (northern sector of the study area), results showed an inverse relationship between the biomass (and density) of fish schools and the biomass of co-occurring plankton patches located close to the bottom. Instead, over the Sicilian-Maltese shelf (Zone 3), characterised by higher plankton abundances, a direct relationship was found when using plankton data from the whole water column. The observed difference between Zones 1 and 3 is probably due to diverse dominant fish species in the two sub-regions.

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