Vertical distribution and morphology of small pelagic fish schools in the Gulf of California

2017 ◽  
Author(s):  
Uriel Rubio-Rodriguez ◽  
Hector Villalobos ◽  
Manuel O. Nevarez-Martinez ◽  
Violeta Gonzalez-Maynez
Keyword(s):  
Vertical Distribution ◽  
Gulf Of California ◽  
Pelagic Fish ◽  
Small Pelagic Fish ◽  
Fish Schools

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.

Hydroacoustical Survey of Near-Surface Distribution, Abundance and Biomass of Small Pelagic Fish in the Gulf of California

2012 ◽  
Vol 66 (3) ◽  
pp. 311-326 ◽  
Author(s):  
José Francisco Domínguez-Contreras ◽  
Carlos J. Robinson ◽  
Jaime Gómez-Gutiérrez
Keyword(s):  
Gulf Of California ◽  
Pelagic Fish ◽  
Small Pelagic Fish ◽  
Surface Distribution ◽  
Near Surface

scholarly journals Interaction between small pelagic purse seine fishery and its top predators

2018 ◽  
Vol 59 (2) ◽  
pp. 185-190
Author(s):  
Barbara Zorica ◽  
Vanja Čikeš Keč ◽  
Kristijan Zanki ◽  
Leon Grubišić ◽  
Tanja Šegvić-Bubić
Keyword(s):  
Preliminary Data ◽  
Negative Impact ◽  
Pelagic Fish ◽  
Purse Seine ◽  
Small Pelagic Fish ◽  
Fish Schools ◽  
Top Predators ◽  
Increasing Trend ◽  
Monthly Pattern ◽  
Purse Seine Fishery

Due to very good collaboration with one commercial purse seiner, using “Srdelara” and operating in fishing zone G, preliminary data concerning the interaction between small pelagic purse seine fishery and its predators were obtained. According to the notes taken by experience observer on-board in period from year 2013 to 2016, seems that tunas, dolphins and swordfish were the faithful companions of purse seiner fisherman with abundance of 68.6%, 22.0% and 9.4%, respectively. Although they were present all year round, their monthly pattern of appearance indicated that less tunas were recorded in May-June, more dolphins were noted from July to October while swordfish were mostly abundant in winter (January-March). Within the investigated period, slightly increasing trend of tuna and dolphins’ appearance was recorded, although statistically not significant. Analysing possible correlation between purse seine catches and predator’s abundances, revealed that appearance of tuna had negative impact on the catches (dispersion of schools), while realised catches in presence of dolphins were quite good so it seems that they tend to round up small pelagic fish schools.

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 Species identification of small pelagic fish schools by means of hydroacoustics in the Eastern Mediterranean Sea

2015 ◽  
Vol 16 (1) ◽  
pp. 151 ◽  
Author(s):  
K. TSAGARAKIS ◽  
M. GIANNOULAKI ◽  
M. M. PYROUNAKI ◽  
A. MACHIAS
Keyword(s):  
Eastern Mediterranean ◽  
Intraspecific Variability ◽  
Aegean Sea ◽  
Pelagic Fish ◽  
Correct Identification ◽  
Small Pelagic Fish ◽  
Fish Schools ◽  
Atlantic Mackerel ◽  
Pooled Data ◽  
The North

  Reliable biomass estimates by means of hydroacoustics largely depend on the correct identification of acoustic targets. Data collected during five summer acoustic surveys (2004-2008) in the North Aegean Sea (Greece) were analyzed to explore effective discrimination of small pelagic fish schools according to the species they belong. Discriminant Function Analyses (DFA) using bathymetric, energetic and morphometric school descriptors as explanatory variables were applied per research cruise as well as to pooled data from all surveys. Results revealed that the schools can be successfully classified into the five species considered (anchovy Engraulis encrasicolus, sardine Sardina pilchardus, round sardinella Sardinella aurita, blue whiting Micromessistius poutassou, and Atlantic mackerel Scomber scombrus). The percentage of correct classifications in terms of number of schools was higher in the analyses of the annual cruises (75.6%-95.36%) than in the analysis of pooled data (≈72%). This is because of (i) the lower number of species, as well as (ii) the reduced intraspecific variability, occurring in each separate cruise. Significant differences were detected among school descriptors for the different species, revealing discrete aspects of schooling behaviour for each species. The benefit of the specific approach is that the classification functions of the DFAs can be used to classify a larger set of schools, which has not been possible to assign to specific species. Overall the approach constitutes an objective, more automated and less time consuming procedure for the analysis of acoustic data and can contribute to the improvement of biomass estimates in the area.

scholarly journals THE IMPORTANCE OF GREY LITERATURE IN FISHERIES ECOLOGY: AN EXAMPLE BASED ON THE THROPHIC ROLE OF SMALL PELAGICS IN THE GULF OF CALIFORNIA

2010 ◽  
Vol 25 (1) ◽  
pp. 59
Author(s):  
M. A. Tripp-Valdez ◽  
S. E. Lluch-Cota ◽  
P. Del Monte-Luna ◽  
C. Salvadeo
Keyword(s):  
Gulf Of California ◽  
Online Survey ◽  
Grey Literature ◽  
Pelagic Fish ◽  
Trophic Relationships ◽  
Detailed Data ◽  
Small Pelagic Fish ◽  
Fisheries Ecology

Grey literature has been, in general, rejected from peer reviewed journals due to the lack of specialized revision and because they are difficult to trace. However, this information may contain detailed data that cannot be found in commercial reviewed journals. In order to assess the importance of grey literature in fisheries ecology, we made an online survey of indexed journals as well as thesis dissertations, technical papers and abstracts from proceedings reporting the trophic relationships of small pelagic fish in the Gulf of California. We obtained 57 bibliographic references from which 36 are considered grey literature, and these would represent a loss of more than 60% of information. This bias can lead to erroneous conclusions in studies and applications derived from such information. La importancia de la literatura gris en la ecología pesquera: un ejemplo basado en el papel de los pelágicos menores en el Golfo de California La literatura gris suele considerase como una fuente de información cuestionable en revistas y publicaciones científicas debido a que carece de una revisión especializada y a que puede constituirse de documentos difíciles de rastrear. Sin embargo, brinda información detallada y de calidad que no se encuentra en las publicaciones con arbitraje estricto. Con el objetivo de ilustrar la importancia de la literatura gris en el ámbito de la ecología pesquera, se realizó una búsqueda en línea de publicaciones en revistas indexadas, en tesis de grado, reportes técnicos y resúmenes de congresos donde se reportan las relaciones tróficas de los pelágicos menores con especies de diversos taxa en el Golfo de California. Se obtuvieron 57 referencias bibliográficas de las cuales 36 son consideradas como literatura gris. Excluir los datos contenidos en estas fuentes de los análisis que se lleven a cabo sobre el tema, podría representar una pérdida de más del 60% de la información disponible. Este sesgo tiene el potencial de producir conclusiones incompletas o erróneas en los estudios de la dinámica trófica de los pelágicos menores en el Golfo de California.

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