SeaStar FAQs
Do the recommendations on my Fish Finding Map guarantee that
I will find fish?
No. The satellites do not see the fish directly, but they do provide observations
of the habitat, thus permitting indirect interpretation of the fish’s environment.
Indirect signs related to fish distribution (food, birds, dolphins, current patterns,
Sea Surface Temperature [SST], etc.) have been used by fishermen for centuries,
but not until recently could information on large areas around the vessel be observed.
Even though SeaStarSM Fish Finding Maps (FFMs) provide observations on favorable
conditions for concentrating fish, it is possible that in some cases no fish will
be found. However, the probability is greater that more fish will be found
in favorable conditions than in unfavorable conditions. Clearly, satellite-derived
observations must be integrated with a fisherman’s expertise, along with such information
as RADAR, SONAR, radio reports from other vessels, prevailing winds, currents, weather,
and sea-state observations, etc.
How old is the data I receive in my Fish Finding Map?
In order to measure plankton concentration, our OrbView®-2 satellite must take images
at 12:00 noon local time. Then, these images are sent to our Dulles, Virginia, USA,
headquarters for processing. In general, Fish Finding Maps (FFMs) are sent to vessels
approximately 18 to 24 hours after data collection. It is important to remember
that the tuna do not eat the plankton directly; therefore, daily changes in phytoplankton
are not as important as more constant oceanographic conditions shown in the FFMs.
Should the Sea Surface Temperature Contours shown on the
Fish Finding Map match exactly what I measure out at sea?
No. The goal of the Sea Surface Temperature (SST) Contours is to present the patterns
of relative change. Although values on the SST Contours are the most accurate available,
the objective is to show the changes over the entire area, not what the exact SST
might be. Satellite-derived measurements of SST are affected by winds and atmospheric
water-vapor content. Thus, they may not correspond with point measurements taken
from the vessel. Without satellites, it is impossible to measure the SST for hundreds
of kilometers around the vessel.
Should I be able to observe the differences in water color
seen on the Fish Finding Map?
Not necessarily. The OrbView-2 satellite is capable of "seeing" six different colors,
whereas the human eye can only respond to three basic colors. Thus, the satellite
“sees” more subtle color differences than the human eye can. By using digital processing
techniques, it is possible to classify these colors in the Fish Finding Maps (FFMs).
Four colors are used to distinguish between water types based on actual concentrations
of phytoplankton. The colors on the FFMs do not signify that the ocean will appear
a particular color, but that the ocean contains a particular amount of plankton.
The Fish Finding Map shows my area as cloudy, but the sky
appears clear.
What’s wrong?
It is possible that this might happen due to a particular set of atmospheric conditions
and to the sensitivity of the sensor on the OrbView-2 satellite. The sensor is highly
perceptive, and it is designed to distinguish minute color differences. Factors
such as haze, thin clouds, water vapor, or even high humidity can interfere with
the imagery. To resolve this problem, various tests are conducted on the satellite
data, and when such atmospheric conditions are present, the computer reports this
excess water vapor as an area that is cloudy. This conservative approach helps us
avoid incorrectly displaying atmospheric effects as areas of increased phytoplankton
concentration.
Where can I get help in understanding the Fish Finding Maps,
and can I recommend changes and enhancements to the format, recommendation style,
or service?
GeoEye’s staff of oceanographers and fisheries biologists are more than happy to
assist you in using your Fish Finding Maps (FFMs) and to better understand the relationship
between fish behavior, the environment, and your particular fishing experience and
fishing strategy. We welcome, and in fact encourage, all suggestions! We use customer
feedback to evaluate how effective the service is and to continually improve the
recommendations as well as the FFM format. In addition, we can analyze your fishing
results to show how you can benefit even more from using the FFMs.
Why do I observe waves coming from a different direction
than is shown in the OrbMap v6.2 Weather Module wave display?
In OrbMap v6.2 the wave information shown under the “Wave Height” icon is now the
“Significant Waves.” Significant Waves combine the waves with the swells to better
estimate the impact of the waves on the vessel. The direction of the significant
waves is defined as the direction that imparts the most energy at a given point.
In areas of low wind-waves but high swells, the significant wave direction will
coincide with that of the swells. In areas of high wind-waves, the significant wave
direction will coincide with that of the winds. Keep in mind that you can monitor
the wind strength by selecting the “Wind” icon in the OrbMap Weather Module. You
can view the swell information by selecting the “Swell” icon.