Sonar estimates of daytime activity levels of Euphausia pacifica in Saanich Inlet

@article{Jaffe1999SonarEO,
  title={Sonar estimates of daytime activity levels of Euphausia pacifica in Saanich Inlet},
  author={Jules S. Jaffe and Mark D. Ohman and Alex De Robertis},
  journal={Canadian Journal of Fisheries and Aquatic Sciences},
  year={1999},
  volume={56},
  pages={2000-2010}
}
A three-dimensional multibeam tracking sonar system (FishTV) was deployed in the stratified waters of Saanich Inlet in July-August of 1996 and 1997 to assess the swimming behavior of euphausiids in situ. Here, a new algorithm is used to estimate swimming velocities of animals from the uncorrelated displacements of acoustic targets in pairs of sonar frames with increasing time delays between frames. Assuming isotropic motions of euphausiids, the superior spatial resolution of the sonar in one… 

Figures and Tables from this paper

Acoustic observations of the swimming behavior of the euphausiid Euphausia pacifica Hansen

Krill (Meganyctiphanes norvegica) swim faster at night

It is hypothesize that krill activity during the first period was limited by oxygen, and the enhanced swimming at night subsequent to the water renewal is due to increased feeding activity under lessened danger of predation in darkness.

Inferring 3-dimensional animal motions from a set of 1-dimensional multibeam returns

Using the methodology developed in this paper, one can obtain a higher accuracy version of the 3-dimensional pdf by using only the range information, and under the assumption of an isotropic distribution of animal motions the three dimensional probability density function for animal displacements should be derivable from a measurement of the one dimensional density function pdf1 d(Δρ).

On Turbulence Production by Swimming Marine Organisms in the Open Ocean and Coastal Waters

Abstract Microstructure and acoustic profile time series were collected near Ocean Station P in the eastern subarctic North Pacific and in Saanich Inlet at the south end of Vancouver Island, British

Validation of acoustic echo counting for studies of zooplankton behavior

OASIS (Optical-Acoustic Submersible Imaging System), an instrument designed for concurrent optical and acoustic imaging of zooplankton, confirms that echo counting is a valuable method for behavioral studies and underscores the importance of independent verification of the identities of acoustic backscatters.

The application of acoustic Doppler current profilers to measure the timing and patterns of coral larval dispersal

An experiment was conducted along the reefs off west Maui, Hawaii, during the summer of 2003 to monitor the spawning of the reef-building coral Montipora capitata and to determine the role of ocean

Observations of Biologically Generated Turbulence in a Coastal Inlet

Measurements in a coastal inlet revealed turbulence that was three to four orders of magnitude larger during the dusk ascent of a dense acoustic-scattering layer of krill than during the day,

Vertical distributions and abundances of life stages of the euphausiid Euphausia pacifica in relation to oxygen and temperature in a seasonally hypoxic fjord

It is broadly assumed that organisms inhabiting seasonally hypoxic estuaries and fjords are stressed by low dissolved oxygen (DO) conditions. However, relatively few zooplankton have shown clear

References

SHOWING 1-10 OF 26 REFERENCES

Three-dimensional swimming behavior of individual zooplankters: observations using the acoustical imaging system FishTV

There is increasing recognition that three-dimensional tracks of individual zoo-plankters are needed for studies in biological oceanography, including, for example, the role of individual behavior in

FTV : a sonar for tracking macrozooplankton in three dimensions

OASIS in the sea: measurement of the acoustic reflectivity of zooplankton with concurrent optical imaging

Energetic costs of swarming behavior for the copepod Dioithona oculata

Results indicate that active metabolism (swimming at maximum speed to maintain the swarm in a current) is approximately three times greater than routine metabolism (normal swimming speeds in the absence of currents), indicating a significant metabolic cost of maintaining swarms in the presence of currents.

Relationship of oxygen consumption to swimming speed in Euphausia pacifica

A comparison with efficiency in fishes 2–3 orders of magnitude larger in weight (efficiency range ∼10–25%) indicates that locomotion in E. pacifica is far less efficient, a probable result of the organism's small size and multiple-paddle mode of propulsion.

ASPECTS OF SCHOOLING IN EUPHAUSIA SUPERBA

Divers observed schools of Euphausia superba off the South Shetland Islands and in Gerlache Strait near the Antarctic Peninsula, indicating that schooling may have epidemiologic disadvantages.

Use of the Pisces IV Submersible for Zooplankton Studies in Coastal Waters of British Columbia

A method for calculating plankton densities from estimates of mean interanimal distances is described, and several species were found to exist within unexpectedly narrow and sharply defined layers, often at densities greatly surpassing density estimates based on net samples.

Swimming Speed and Oxygen Consumption in the Bathypelagic Mysid Gnathophausia ingens

The energetic costs of swimming were deter mined for the bathypelagic Gnathophausia and found that swimming efficiency increased with speed, and the lower cost of transport and higher swimming efficiency may contribute to G. ingens ' reduced rates of oxygen con sumption as compared to those of shallower-living crus taceans.

Energetic cost of position-holding behavior in the planktonic mysid Mysidium columbiae

In situ videotapes indicate that the planktonic mysid Mysidium columbiae exhibits positive rheotactic behavior and can use prop roots and other objects as visual cues to maintain position in currents

Locomotion and visual behaviour of mid-Water crustaceans

Video recordings were made of the behaviour of hyperiid amphipods and other mid-water crustaceans in a tank lit from above with a dim VDU screen and from behind with infra-red light, finding three kinds of visual behaviour seen consistently.