Biology Reference
In-Depth Information
seasonal climatic and hydrological variations (Keith,
2003). These species
spawn in freshwater, the free embryos drift downstream to the sea where
they undergo a planktonic phase, before returning to the rivers to grow and
reproduce, hence they are called amphidromous (McDowall, 1997, 2007).
The practical details of their biological cycle and the parameters leading
to such extreme evolution in amphidromous gobies are poorly known
(Lord and Keith, 2007), despite the fact that these gobies contribute most
to the diversity of fi sh communities in the Indo-Pacifi c and the Caribbean
insular systems, have the highest levels of endemism (Nelson et al., 1997;
Keith and Lord, 2010) and a high economic value as food resource for local
populations.
Sicyopterus lagocephalus
(Pallas, 1767), distributed from the western
Indian Ocean to the eastern Pacifi c one, is one of them. After reproduction,
the free embryos of this species are carried out to sea by the river fl ow
(Valade et al., 2009). When reaching the sea, the embryos transform into
planktonic larvae which are dispersed by oceanic current during 130 to 266
days (Lord et al., 2010). After spending several months at sea as larvae, they
need to return to freshwaters to achieve their life cycle (Keith et al.
,
2005)
(Fig. 1). Soon after entering freshwaters, the post-larvae undergo several
changes in colour, body and fi ns shape and have a metamorphosis switching
from a planktonic to a benthic feeding mode (Keith et al., 2008). This is the
Figure 1.
S.
lagocephalus
amphidromous life cycle.
Color image of this figure appears in the color plate section at the end of the topic.
