Abdenour,

If you explain what exactly you are trying to do with those measurements (what hypothesis are you testing?) it may help folks give you some ideas.

Tomas

Dear Thomas,

Thank you for your interest. I am trying to estimate their population in my coastal region. I will do it in the summer, from June to september. No one did that before in my region, so its in my future project. If u had any idea, that will be very helpfull. I can also see the difference between two sites (polluted or not)...Bioindicator like Posidonia oceanica.

Sincerly

Abdenour:

Here are some ideas for you if your objective is not to disturb the habitat.

Holothuria forskali:

You can easily measure both the body length and body width of the sea cucumbers in the field with a tape measure and calipers. However, you have to do it gently without triggering contraction in the sea cucumber.

Pinna nobilis :

You can measure the longest length, widest width and thickness of the shell with tape and calipers. Do these measurements once the pen shell closes.

Posidonia oceanica:

1) Measure density of shoots as number of shoots per unit area (example 50cm x 50cm quadrat).

2) Measure shoot length

3) Measure shoot with

4) Measure the biomass of epiphytes on the shoots by sampling shoots and bringing them to lab then scraping the epiphytes from a known area, drying it and getting their weight.

I have attached a few paper for you to have a look.

Hope this helps a bit.

Tomas

Dear Tom,

I don't know how to thank you for your contribution. These species and others are included in a long list. So, biodiversity protector can understand another one. My project is to create a conservation or a protected area based on serious studies of some important species. I'm always under water like you, so I know that Pinna nobilis have a beautiful creature living inside. When I was talknig about Holothuria, contracture can be a problem  and for Posidonia, it was my first subject of thesis.

Hope one day working together.

Sincerly