Tanga Fisheries Analysis - IUCN

4. Summary Description of Previous and Current Fisheries Sampling Protocols in
TCZCDP
Why Sample? Sometimes, the entire population will be sufficiently small, and the researcher can include the entire
population in the study. This type of research is called a census study because data is gathered on every member of
the population. Usually, the population is too large for the researcher to attempt to survey all of its members. A small,
but carefully chosen sample can be used to represent the population. The sample reflects the characteristics of the
population from which it is drawn. (Source: Statpac Survey Software, Sampling Methods)
In order to know whether management activities are having the desired affect in terms of improving
incomes of small-scale fishers or increasing the abundance of particular species (etc.), managers
need to have information from the fishery itself. But obtaining information on every catch landed or
price obtained etc from fishers is usually impractical because it is expensive and time-consuming,
especially in small-scale fisheries where there are many small, isolated landing sites often with
poor access. So sampling protocols are usually developed, which give a statistically accurate
picture of the fishery but only require a certain number of fishing trips to be recorded. These
sample data are then used in conjunction with the frame survey data (as described in Section 3) to
estimate total catch/revenue.
There have been three distinct sampling protocols employed under the TCZCDP. At the time of
inception of TCZCDP the Fisheries Division operated a sampling regime at six landing sites in
Tanga Region (see Table 5).
Table 5 - Landing Sites Sampled by Fisheries Division (Tanga Region)
Landing Site
Moa
Kwale
Kigombe
Tongoni
Deep Sea
Kipumbwi
Source: Fisheries Division
District
Muheza
Muheza
Muheza
Tanga
Tanga
Pangani
A range of data were (and continue) to be collected and these are presented in Table 6. The
sampling methodology was based on 16-days sampling per month at the six sites with an expected
100% coverage of the fishing activities on those days, i.e. all boats that land a catch on a given
sampling day should be interviewed and the catch/effort recorded. Note that data were not
collected according to scientific nomenclature but using local taxonomy, which tends to group a
number of species and genera (and in some cases families) together under species groupings.
Table 6 - Profile of Fisheries Data collected by Fisheries Division
Effort Data
Date
Vessel Registration Number
Vessel Type
Gear Type, Number and size
Number of Crew
Arrival Time
Time Spent Fishing
Catch Data
Weight by species (groupings)
Number by species (groupings)
Economic Data
Value of catch (beach price) by species (groupings)
Source: Fisheries Division
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