There are different kinds of fish farms that use different aquaculture methods.

Dear Prof.,

Nursery grounds are very important yet delicate environments that should be given more consideration because it determine the future of fish class every year. These areas should be legally protected to conserve its health and plans should be put to improve it in order to make wider advantage by many fish species that use this area for reproduction or juvenile rearing especially the threatened species as the case in southern marshes of Iraq.

Best regards

SM Najim

yes, Dr.Najim , the nursery grounds should be protected from ill legal fishing. it is also should be investigated regularly to protect these area.

Dear Mohamed E Megahed,

yes, indeed. The nursery ground should be protected. Thanks for your comments. Regards

Hi Noori,

In order to begin to answer your two (not easy) questions:

1) How do you describe the functioning of fish nursery grounds

Depends what you mean by "functioning" but number of fish species present

as juveniles and their relative abundances are the basic information.

If you need/can go deeper into details, individual growth rates using otoliths, food web coupling (using isotopes), connectivity to adults habitats (or other nurseries) using different techniques are important questions you can also address.

2) how these grounds can be investigated

you first need unbiased sampling techniques (can be quite tricky in some environments)

you also need good identification guides if juveniles are different from adults

Wish you the best

Dominique

We currently work on the nursery ground functionality of estuaries for several marine and estuarine fish species. We look at two specific aspects for identifying the nursery area. The density of juveniles found and the time they spend on the area. We use a beam trawl to sample the juvenile fish and because the it is generally shallow water, we get demersal and pelagic species in the sample. By surveying regularly at least once a month during spring and early summer, we can have an idea of the mean month growth for some species. We are also trying to identify right now the favorability of two nursery areas using fatty acids analysis that can tell something about the physiological condition of the post-larvae. We also had done an extensive study of the nursery areas for sturgeon Acipenser sturio in the Gironde estuary by trawl sampling and fish telemetry. You can find some papers on my RG profile.

Good luck

Mario

Dear Maric  lepage ,

Thanks for feed back. I  am going to read your papers. I would like to know more about fatty acid analysis.

Thanks & regards

Your question is a little too broad and, without a species in question and an understanding of their life history, is hard to answer. That said, I work stream Salmonid species in montane environments and can approach the question from that perspective . From what I've read and observed many juvenile salmon/trout utilize slower moving areas associated with shallow near bank/edge habitats and also utilize heavily vegetated habitat for nursery areas. Accurate sampling at this life stage is crucial and for stream Salmonids is often accomplished using seines or backpack electrofishing. In terms of functioning, I'm curious if you are getting at a recruitment question where the primary concern is the use of nursery areas and their impact on recruitment to adulthood. In this case one might consider trying to sample habitats that are well known nursery areas versus lesser known/other habitat areas and do some form of mark-recapture study to identify how certain nursery habitats function in terms of differential survival/recruitment in comparison to fish sampled from other habitats.

Dear Jeremy L. Kientz,

Thanks for your useful feedback.

regards

I consider a nursery area to be where juvenile organisms can be found in large numbers compared to other types of habitat.  It should contain adequate food for those numbers and relative protection from predation on them.

As for sampling such areas, I suggest you see my web site herke-estuarine-fisheries.com .  The publications listed there will detail how I and my colleagues have sampled in such areas.

Most of the publications are listed only by title, but I will be happy to send full text of those you request.

Dear William Herke,

Thanks for you important comments. Yes, food , habitat type and  predation   are important factors for juvenile fishes. could you send me coy  of your recent publication.

Thanks

I am unsure of which publication you are referring to.  Please go to the Free Reprints section of my web site    www.herke-estuarine-fisheries.com    and pick the one or ones you want.  The publications are numbered and you can request them by their number; there is no need to type out the title etc.  Most of them are in hard paper copy so it will take me a while to scan them so I can send them electronically..  Meanwhile I am attaching an electronic summary of several.  It includes details of how we have sampled in nursery areas.

Thanks all for your valuable comments

The large number of fishes and marine invertebrates using mangrove habitats during the juvenile stage of their life cycles, where the mangrove prop-roots make a particular underwater habitat, particularly through the breeding and juvenile stages The availability of mangrove nursery habitat had a significant impact on the community structure and biomass of reef fish in their adult, coral reef habitat.

Heupel et al. (2007) suggested that nursery grounds could be identified depending on three criteria, (1) the density of juveniles was greater than in other areas, (2) there would be greater site fidelity, and (3) the nursery area was used repeatedly over the years