Biophysical Survey of Mafia Island Marine Reserves

stop off or shelter. Boats from the mainland were frequently observed to anchor off the
fishing camp at Nyororo to rest before night fishing with nets and lamps off the north-
west of Mafia. Growth of the settlement is limited by fresh water which must be
imported. Local information suggests that there was once a good supply of fresh water
available from a bore hole on the island but that over-use has resulted in the water
becoming brackish and no longer drinkable.
During the season of the northerly monsoon the camp was restricted to a
remainder of around 30 fishers, who were originally from many different coastal districts
in Tanzania, although it could at other times support many times this number. During the
high season fishers are reported to come from many coastal regions on the mainland, and
from Mafia, to setup temporary camp on Nyororo due to the high quality of the fishing.
Many fish species are targeted opportunistically: unicorn fish (Naso sp.), groupers
(Serranidae sp.), surgeon fish (Acanthurus sp.), parrot fish (Scaridae sp.) and a moray eel
(Muraenidae sp.) were present on the drying racks on a visit to the camp. Octopus forms
the mainstay of the commercial species targeted by fishers based on Nyororo Island.
From 250 to 300 individuals were present on the camp and available for purchase at
Tsh1600 per kilo during one visit. Octopus soup was also available. A few marine curios,
notably the bullmouth helmet shell and triton trumpet shell, were present and prepared for
sale. There have been reports that dynamite fishing is sometimes carried out on reefs
within NIMR. Further work would be needed to ascertain the locations and extent of the
use of this practice.
B. Shungimbili Island Marine Reserve (SIMR)
1. Reserve Mapping
A patch mosaic was created from the low resolution satellite image in conjunction
with benthic cover data, spot checks, and habitat patch boundary tracking (Figure 13).
The mapping process showed that the main coral reef habitat is found on the northern and
eastern sides of the island, around 1km distant from the island. The reef is approximately