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Species distribution maps for OSMOSE

Dear Sir/Ma'am,
While defining distribution maps for each species in OSMOSE, I understand that each map is associated to a unique species for given age span, year span and season. In case we do not have any information about the age span for a given species (let's say species name is sp01)
Query 1:
Due to the scarcity of information with respect to age, seasonality in fish distribution, can we assign the parameters movement.map01.age.min = 0 and movement.map01.age.max = species.lifespan.sp01 ? By doing so, are there any trade-offs that we should be aware of before running the OSMOSE model?

Query 2:
Are there any alternate methods/tools/data sources with the help of which the end-users can construct relaible species distribution maps (or maps of probability of presence) corresponding to individual time-step?
Query 3:
Apart from the existing literature, are there any other data sources which you can suggest for providing information about the seasonality and age span associated with spatial distribution of fish species so that the users can porvide appropriate values for parameters such as  movement.map#.season, movement.map#.age.min and movement.map#.age.max ?
In case, data (even with respect to existing literature) is scarce, could you provide your input on what could be done to generate the species distribution maps required for individual time-step?
Kind regards,
Tarun Joseph

Hello Tarun Joseph,
I am an OSMOSE user. Hope my reply could help you.
Q1:
The parameter movement.map#.age is described as age span of the schools associated to the map such as age.min <= age < age.max. If you assign the parameters movement.map01.age.min = 0 and movement.map01.age.max = species.lifespan.sp01, it means all age groups of sp01 could distribute in map01-sp01.csv. You can also set the parameter movement.map#.age to control the species’ season distribution.
Details as follows:
http://www.osmose-model.org/documentation/description-input-parameters-osmose-3-update-1#toc-21
#6 Movement parameters
Q2:
As far as I know, there are no useful tools for constructing reliable species distribution maps. In my view, survey data are reliable for constructing species distribution maps.
Q3:
It is a hard question to answer. In my opinion, if you have more data, you will make your simulation better. I think Philippe will give you a better answer for this question.
Best regards,
Lei Xing

Hello  Lei Xing
Thank you for your input. We really appreciate your help.
Kind regards,
Tarun Joseph

Dear Tarun and Lei Xing,

Defining distribution maps is indeed a difficult step in setting up a new Osmose configuration, espacially when little information is available for certain species.

Defining a single distribution map for the whole species seems reasonable enough if you do not know anything at all about your species. We usally separate maps for eggs/juvenile and adults and include some seasonality but you need elements to do so, otherwise you are just taking a guess and there is no way to justify such choices in a paper.

I do not know about specifc tools for creating distribution maps but I reckon there are many available in R since it is the whole purpose of ecological niche modelling. I am rather ignorant of this approach and cannot advise any scientific papers but you may check for Sandrine Vaz (ifremer, France) publications, as I know for sure she worked on this field of research.

Besides scientific litterature and ecological niche modelling output, you may gather information on unknown species distribution by (i) asking experts, fisherman, etc. and by (ii) checking whether they are other species that share many traits with your species and hyptothesize they may have similar habitat ?

From the modelling point of view (for stability), if you do not know where to set the limit I would suggest that (i) your maps are not too clustered, and (ii) they do overlap generously between species.

Cheers, Philippe