Robust Methods for the Analysis of Images and Videos for Fisheries Stock Assessment Summary of a Workshop (2015) / Chapter Skim
Currently Skimming:
3 Multi-Modal Sensing
3 Multi-Modal Sensing
Pages 21-28
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 21... ...
The resulting time series enables one to gauge trends, measure length, and obtain physical samples. She noted that single data points are not particularly helpful, as fish tend to aggregate; any single measurement gives little information about the number of individuals living throughout a region of interest because it can be too high or too low depending on whether an aggregated mass of fish is observed.
|
From page 22... ...
However, the estimate of natural mortality is highly uncertain and can vary in time, leading to a corresponding uncertainty in total mortality. Ironically, as fishing mor tality rates approach natural mortality rates (a desired outcome)
|
From page 23... ...
The decrease in population from 2010 to 2012 may be the result of h species temperature effects; increased bottom water temperatures may be causing popula tions to decline, said Hart. ate, estimates have been obtained for one finfish s Hart concluded by reiterating that absolute scale is difficult to obtain, particu larly when fishing mortality is at an appropriately low level.
|
From page 24... ...
SYNERGISTIC ACOUSTIC AND OPTIC OBSERVATION AND ESTIMATION Jules Jaffe, University of California, San Diego Jules Jaffe explained that he was interested in observing different marine life using both acoustic and optic observations. He explained the general differences between acoustic and optic observation using the information in Table 3.1.
|
From page 25... ...
He explained that immature myctophids have an air bladder that reflects acoustic energy well; in adulthood, the animals do not retain the swim bladder, and their acoustic reflection profile is smaller as a result. Jaffe described an observing system called OmniCam used to study mesopelagic swarms seen via acoustic backscatter.
|
From page 26... ...
. These were fairly extensive efforts, similar to those used in typical trawl surveys, consisting of an OAWRS source ship, OAWRS receiver ship, and one or two ships using conventional echo sounding and trawl.
|
From page 27... ...
In contrast, audible sound can travel nearly around the world, and long electromagnetic wavelengths can penetrate water. SEAFLOOR LASER IMAGING TECHNIQUES Fraser Dalgleish, Florida Atlantic University Fraser Dalgleish explained that he pairs emerging laser technologies with spa tially and temporally resolved methods of imaging.
|
From page 28... ...
Dalgleish concluded by stating that serial laser imaging techniques offer im proved image contrast and range of operation relative to cameras. Field tests have shown that distributed serial laser systems can provide images under a wide range of conditions with relatively simple, compact hardware.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.