Tanga Fisheries Analysis - IUCN

Figure 21 - Proportion of Monthly Catch of Lethrinidae (Ngalawa/Mishipi)
Proportion of Monthly Catch
Lethrinidae Caught by Ngalawa/Mishipi
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1995 10
1996 1
1996 4
1996 7
1996 10
1997 1
1997 4
1997 7
1997 10
1998 1
1998 4
1998 7
1998 10
1999 1
1999 4
1999 7
1999 10
2000 1
2000 4
2000 7
2000 10
2001 1
2001 4
2001 7
2001 10
2002 1
2002 4
2002 7
2002 10
2003 1
2003 4
2003 7
2003 10
Proportion of Total Monthly Catch
2004 1
2004 4
2004 7
Year/Month
Figure 22 presents data on catches of Lethrinidae using madema. The data show a very strong
seasonality in the capture these species, with clear peaks at the same time of year (Kusi) as with
the mishipi fishery, but with very few data outside of this period. In both cases, the same type of
vessel is being used, but Lethrinidae appear to be much more seasonally available. The question
of whether the fishers are operating in different grounds might be accounted for by the fact that the
peaks in Lethrinidae are at approximately the same time each year. So assuming the fishers are
using the same grounds each year, these data would seem to indicate a strong seasonal variation
in Lethrinidae’s vulnerability to madema. Again there is little in the way of an apparent increase in
the relative abundance of these species in the catch.
Figure 22 - Proportion of Monthly Catch of Lethrinidae (Ngalawa/Madema)
Proportion of Monthly Catch
Lethrinidae Caught by Ngalawa/Madema
Proportion of Total Monthly Catch
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1995 10
1996 1
1996 4
1996 7
1996 10
1997 1
1997 4
1997 7
1997 10
1998 1
1998 4
1998 7
1998 10
1999 1
1999 4
1999 7
1999 10
2000 1
2000 4
2000 7
2000 10
2001 1
2001 4
2001 7
2001 10
2002 1
2002 4
2002 7
2002 10
2003 1
2003 4
2003 7
2003 10
2004 1
2004 4
2004 7
Year/Month
So overall, there is little evidence that the populations of the groups that these species belong to
are showing any sort of dramatic recovery in abundance. This might be because the period since
the beach-seine ban was introduced is still relatively short and it might also be because the ban on
both beach-seining and dynamite-fishing is not complied with. There is evidence for example from
TCZCDP records that the use of beach-seines persists (TCZCDP Mid-Term Review, 2001).
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