To anyone tht can help:
>
> I'm interested in collecting samples of eggs from a fish that is known to have sticky, negatively buoyant eggs,
but
> whose spawning site is not known. The constraints are that the possible spawning areas are likely to be deep
> (>50 m < 200 m), and the substrate unknown, plus we are not likely to have access to substantial benthic
grabs.
> How do we sample the eggs? Someone suggested coconut fibre matting, to which the eggs whould adhere. I'm
> concerned that hauling doormats up from depth would flush out any eggs, unless they really were
super-adhesive.
> Can anyone suggest an ACME deep benthic fish-egg sampling device?
>
> For those curious about this mystery fish, it is Engraulicypris sardella from Lake Malawi. Previously thought to
> have pelagic eggs, intensive surveys done a few years ago (reported in Thompson, A.B. 1996 J. Plankton Res.
> 18: 1349-1368) found few eggs but many newly hatched larvae. The conclusion drawn from this and previous
> studies was that pelagic eggs are unlikely - (discussion in Thompson, p 1363). Reviewing cyprinid life-histories
> suggests the same conclusion. Similarly, if E. sardella spawned in shallow waters, local fishermen would know
> about it. We have surveyed 'indigenous knowledge' on possible spawning sites, and the indications from
> fishermen are that the sites are deep in the parts of the lake where there are strong currents, but they admit to
not
> knowing for sure.
>
> As this fish supports one of Malawi's most important fisheries, finding its spawning habitat is interesting from the
> applied point of view, as well as contributing knowledge to the life history strategies of tropical cyprinids.
>
many thanks,
David
David Hutchinson
School of Biological Sciences
University of East Anglia
Norwich
NR4 7TG
UK
***************************************************************
<To leave send SIGNOFF FISH-SCI to [log in to unmask]>
<For information send INFO FISH-SCI to [log in to unmask]>
***************************************************************
|
