scholarly journals Influence of Trawl Geometry and Vertical Distribution of Fish on Sampling with Bottom Trawl

1986 ◽  
Vol 7 ◽  
pp. 35-42 ◽  
Author(s):  
A Engås ◽  
O R Godø
Keyword(s):  
Vertical Distribution ◽  
Bottom Trawl ◽  
Distribution Of Fish

Vertical Distribution of Fish Biomass in Lake Superior: Implications for Day Bottom Trawl Surveys

2007 ◽  
Vol 27 (3) ◽  
pp. 735-749 ◽  
Author(s):  
Jason D. Stockwell ◽  
Daniel L. Yule ◽  
Thomas R. Hrabik ◽  
Jean V. Adams ◽  
Owen T. Gorman ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Lake Superior ◽  
Bottom Trawl ◽  
Fish Biomass ◽  
Distribution Of Fish ◽  
Trawl Surveys

scholarly journals Vertical distribution of fish larvae in the Canaries-African coastal transition zone in summer

2006 ◽  
Vol 149 (4) ◽  
pp. 885-897 ◽  
Author(s):  
J.M. Rodríguez ◽  
S. Hernández-León ◽  
E.D. Barton
Keyword(s):  
Vertical Distribution ◽  
Transition Zone ◽  
Fish Larvae ◽  
Distribution Of Fish

scholarly journals Vertical distribution of fish and krill beneath water of varying optical properties

1996 ◽  
Vol 136 ◽  
pp. 51-58 ◽  
Author(s):  
S Kaartvedt ◽  
W Melle ◽  
T Knutsen ◽  
HR Skjoldal
Keyword(s):  
Optical Properties ◽  
Vertical Distribution ◽  
Distribution Of Fish

scholarly journals Seasonal shifts in the vertical distribution of fish in a shallow coastal area

2016 ◽  
Vol 73 (9) ◽  
pp. 2278-2287 ◽  
Author(s):  
Noora Mustamäki ◽  
Henri Jokinen ◽  
Matias Scheinin ◽  
Erik Bonsdorff ◽  
Johanna Mattila
Keyword(s):  
Vertical Distribution ◽  
Sampling Design ◽  
Juvenile Fish ◽  
Trophic Levels ◽  
Strongly Correlated ◽  
High Connectivity ◽  
The Vertical Distribution ◽  
Spatial Resource Partitioning ◽  
Distribution Of Fish ◽  
Shallow Coastal Area

Abstract Depth structures aquatic habitats, creating substantial differences in the species composition of underwater communities even at small intervals. Those communities also undergo considerable cyclic variation annually. In this study, we surveyed variation in the vertical distribution of fish in a shallow (20 m) coastal basin in the northern Baltic Sea during the ice-free period from May to October. The waters were strongly mixed throughout the season and only transient signs of stratification were observed. As production shifted towards higher trophic levels over summer, with sequential biomass peaks in zooplankton and juvenile fish, the vertical distribution of the entire fish assemblage became increasingly even. The results suggest that spatial resource partitioning can be strongly correlated with seasonal productivity cycles even in physically uniform environments with high connectivity. Further, the results stress the importance of sampling design (seasonal and vertical coverage) of fish studies in shallow coastal areas.

An Acoustic Study of Shrimp (Pandalus montagui) Distribution near Resolution Island (Eastern Hudson Strait)

1992 ◽  
Vol 49 (5) ◽  
pp. 842-856 ◽  
Author(s):  
R. E. Crawford ◽  
C. Hudon ◽  
D. G. Parsons
Keyword(s):  
Vertical Distribution ◽  
Vertical Migration ◽  
Horizontal Distribution ◽  
Bottom Trawl ◽  
Diel Migration ◽  
Acoustic Study ◽  
Downward Migration ◽  
Plankton Sampler ◽  
Horizontal And Vertical Distribution

Echo integration, a multistage plankton sampler (BIONESS), and a bottom trawl were used to examine the horizontal and vertical distribution of shrimp (Pandalus montagui) near Resolution Island in eastern Hudson Strait. Shrimp were concentrated in two locations within the study area and they maintained this pattern of horizontal distribution for at least 7 d. Acoustic observations revealed a scale of horizontal patchiness that was obscured by the "homogenization effect" of sampling by bottom trawl and plankton net. The shrimp underwent a nocturnal vertical migration with other zooplankton to > 200 m from the bottom and a subsequent downward migration during early daylight hours. This diel migration resulted in reduced availability of shrimp to the bottom trawl at night. Timing of the migrations varied, possibly as a result of interaction with oceanographic processes.

Multispecies acoustic dead-zone correction and bias ratio estimates between acoustic and bottom-trawl data

2017 ◽  
Vol 75 (1) ◽  
pp. 361-373 ◽  
Author(s):  
Kotaro Ono ◽  
Stan Kotwicki ◽  
Gjert E Dingsør ◽  
Espen Johnsen
Keyword(s):  
Vertical Distribution ◽  
Barents Sea ◽  
Dead Zone ◽  
Light Level ◽  
Influential Factors ◽  
Bottom Trawl ◽  
Fish Density ◽  
Melanogrammus Aeglefinus ◽  
Residual Variance ◽  
Bias Ratio

Abstract In this study, we extended the original work of Kotwicki et al. (2013. Combining bottom trawl and acoustic data to model acoustic dead zone correction and bottom trawl efficiency parameters for semipelagic species. Canadian Journal of Fisheries and Aquatic Sciences 70: 208–219) to jointly estimate the acoustic dead-zone correction, the bias ratio, and the gear efficiency for multiple species by using simultaneously collected acoustic and bottom-trawl data. The model was applied to cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in the Barents Sea and demonstrated a better or similar performance compared with a single species approach. The vertical distribution of cod and haddock was highly variable and was influenced by light level, water temperature, salinity, and depth. Temperature and sunlight were the most influential factors in this study. Increase in temperature resulted in decreasing catch and fish density in the acoustic dead zone (ADZ), while increasing sun altitude (surrogate for light level) increased the catch and fish density in the ADZ. The catch and density of haddock in the ADZ also increased at the lowest sun altitude level (shortly after midnight). Generally, the density of cod and haddock changed more rapidly in the ADZ than in the catch (from bottom to the effective fishing height) indicating the importance of modelling fish density in the ADZ. Finally, the uncorrelated variability in the annual residual variance of cod and haddock further strengthen the conclusion that species vertical distribution changes frequently and that there are probably many other unobserved environmental variables that affect them independently.

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