Where have all the big fish gone? Long time passing? where oh where! Fishermen ate them everyone, long time ago! (with apologies and thanks to Bob Dylan)
Large sub adult male humphead wrasse on Sipadan island, the only place on the east coast of Sabah with a breeding population. |
Scary fact--- The biggest wrasse and one of the most charismatic fish on a coral reef is almost extinct in the Semporna region.
TRACC divers have just
finished (Dec 2013) a coral reef survey of Timbun mata island, a large volcanic
island (70km long) to the north of Semporna. The ocean surrounding Pulau Timbun Mata is not
legally protected but the land is technically a forest reserve,
there were plenty of big trees but the mangrove was definitely being
harvested close to Semporna.
On the north side the island has a
fringing reef with quite steep slopes. Severely bombed in parts but
there were a few remote areas which still had good coral cover.
While
the sea bed cover varies with the amount of blast fishing and other
variables there was at least 50% live seabed at all the offshore reef
sites to the north of Timbun Mata. In many places, the living reef
cover exceeded 80% and was very biodiverse with a wide range of
different species.
Fish pots made of wire have decimated reef fish populations in some areas. This pot is upside down. |
The
low fish diversity and abundance is most probably related to the
widespread use of fish pots. At some sites more than 5 fishpots
/100m were recorded. There were very few fish of commercial size at
any site. Blast fishing was widespread and there is a clear gradient
of blast fishing from high close to the villages to low at the reefs
further from the villages. Some reefs were reduced to rubble with
very low fish and coral diversity and abundance, however most reefs
were patchy with blast damage confined to the shallower reefs. Reefs
at 10-15m were relatively intact with high coral cover and diversity.
Femaile Humphead wrasse have no hump But have a characteristic eye stripe |
Other
species are also severely overfished, very few grouper (Serranidae)
or other commercial fish were observed during the surveys. These
results from Nina Ho and Ken Kassem in 2009 and from TRACC in 2013
indicate severe overfishing of these commercially and ecologically
important species.
There is a small population on Pulau Sipadan, where does it get its recruits from? The island is too small to hope that larvae find their way back to the tiny island. From the TRACC surveys around the whole coast it is clear that there is no other population upcurrent from any of the Semporna islands.
More info on humphead wrasse and the live fish trade.
If the humphead wrasse of Sipadan die because of recruitment failure then the species will be regionally extinct and will deserve to be upgraded from endangered to critical (IUCN red list).
Ho,
Nina & Kassem, Kenneth. (2009). Reef Status of Semporna Priority
Conservation Area. Kota Kinabalu,
Malaysia:
WWF-Malaysia