West Coast Groundfish Observer Program Manual, Part2 - NOAA

CHAPTER 5
Tip* When doing an average weight calculation,
count and weigh as many individuals as possible. At
minimum, 15 individuals should be weighed and
counted. For species that are caught in large
quantities, count and weigh at least 50 individuals.
Using Delivery Weights for Average Weights of Tallied
Individuals
Because fishers participating in the live fish market are
extremely concerned about the condition of their fish,
collecting retained individuals may not be possible.
Observers can use delivery weights (fish tickets) to
calculate the average weight of species on these vessels.
1. Tally ALL retained individuals by species for every
haul.
2. Observe the weighing of the fish by species upon
landing, if possible. If not, ask the skipper for a
copy or look at the weights on the fish ticket.
3. Calculate average weight of species by:
Avg. Species Weight = Landing weight of species (lbs)_________
# Of individuals of species caught during ENTIRE trip
4. For each haul, calculate the weight of retained species.
Species Wt by Haul = Avg. Species Wt X # of individuals caught in haul
Tip* Any time average weight calculations are
used to determine a species weight, sample
method 4 – Fixed Gear Sample should be used
on the Species Composition Form. This can be
confusing when delivery weights are used because
all the fish for the trip are weighed. However,
Sample Method 1 – Whole Haul refers to a haul
1/30/2004 5-45