Well the windy season is in full swing down here at Kande Beach but we are keeping busy nonetheless. Rob, our research assistant, has done a great job going through our fisheries monitoring program data. See the results below! And here is a nice photo of our current Maru team. We have fun here too!
And now Rob's report -
Over the past four years, we here at the
Maru have regularly undertaken fisheries surveys at the local fishing village
of Masakuhunju. This village is home to
fishers who primarily target the “Utaka” fishery. Utaka are cichlids in the genus Copadichromis.
Our data provides us with three indicators of the pressure on these fisheries;
fishing effort in terms of working canoes each day (both landed and boats still
coming in when we arrive); total canoes at the village (both working and
non-working – so as to provide an idea of the total number of fishermen
operating out of the village at any given point; and finally total estimated
landed catch. In order to calculate the total estimated landed catch we weigh
20% of the working canoes on the beach when we arrive. A mean figure is
calculated for all the boats weighed, and this is extrapolated to 100% of the
working boats.
Our findings thus far have enabled us to
chart seasonal and annual patterns.
Figure 1 shows the total number of canoes
in the village.
Figure 1.
We started recording this aspect of the
dataset in late 2013, and for the most part we have counted somewhere in the
region of 40-60 canoes each day. The only deviation from this is a clear peak
occurring in the second half of 2014. The total number of canoes at Masakahunju
almost doubles to around 80-100 canoes each day. This number did fall as the
year closed out, and unfortunately apart from the end of 2013, data is
insufficient for the third quarter of each other year we have been recording.
This was due to having a lack of interns at the research centre during these
months. One explanation for this pattern could be that because the windy season
on the lake finishes around the end of July, a number of part-time fishermen
use the seasonal opportunity to ply their trade at fishing, whilst holding a
different occupation for the rougher months.
While total number of boats at the village
is a relevant indicator of potential fishing pressure, it is a more telling statistic
when compared to the total number of working canoes. Figure 2 shows how this
number has varied over the past four years.
Figure
2.
The total number of working canoes shows
very much a similar story to the total number of canoes at the village. For the
most part, in the first half of the year the number varies between 10 and 20
boats going out each day; we see in the second half of 2014 that the numbers
start to increase to almost double again (as with total canoes in the village),
this time to around 20-30 boats each day. In general there are two more points
of note in Figure 2 than in Figure 1. Firstly there seems to be very little
working boats heading out for the entirety of 2015. Data was missing for
August, September and December for that year, but the number barely exceeds a
mean of 5 working canoes per day for any month that year. The second point of
note is that in February 2016, the number of working canoes per day averaged
just fewer than 30. This seems unseasonably high given all the data we have
reviewed hitherto, as the figures for the month of February in 2013 and 2014
were half this and the figure for February in 2015 was as low as 3.8.
Perhaps our most direct indicator of
fishing effort is the total estimated landed catch. Figure 3 shows the seasonal
variation for the mean daily values in total estimated landed catch.
Figure 3.
Immediately one can some consistencies with
the seasonal patterns of the other two indicators. For the first half of all
four years the total estimated catch varies between 50 and 300lbs per day.
Again, in 2014 this increases for the second half, and starts to fall in the
final months of the year. Interestingly, in 2013 there is an increase in total
estimated landed catch, though this appears to happen from October to December,
slightly later than in 2014. The only other year in which there is data for any
point in the fourth quarter is 2015 – and here for the months of October and
November, the total estimated catch was between 350 and 400lbs on average each
day. This is an impressive feat, as Figure 2 shows that very few boats were
going out each day for any month that year.
We at the Maru are still in the process of
going through the statistical analysis of this data, but these graphs allow us
to make qualitative inferences on the amount of fishing pressure exerted by the
fishermen at Masakahunju. In terms of working boats and total boats at the
village, there seems to be a fair amount of sporadic variation between the
daily, monthly and yearly scale. Crucially, 2015 showed fewer working canoes in
general than the other years, yet their total estimated catches did not seem to
be significantly lower than for 2013, 2014 or 2016. In the second half of 2014
there was evidently an increase in fishing pressure, as for all three
indicators the figures effectively double, with the onset starting around the
end of July. Whether this was just for 2014, or rather a typical seasonal
pattern observed year in year out, is currently unclear due to the gaps in our
dataset. Ultimately we can say that there has been no visible crash in the
total estimated landed catch, and that has resulted in a seemingly similar
stability in the total working boats, and total boats in the village; this
would suggest that the fisheries in this part of the lake are currently being
fished to a sustainable level.
The only way to know for sure, is of course
to continue collecting this data, which is exactly what we intend to do.
News from the Beach! Some analysis of our fisheries monitoring data
