Invest Fisheries model

Mery_khMery_kh Member
edited December 2016 in Marine Models
Hi NatCap,

I'm trying to apply the "InVEst fisheries" model for the Mediterranean hake fishery, whose objective is to test different management scenarios, in particular the closure of an area for fishing. I have some doubts about the correct design of the data required for the model (inputs) and I hope to find answers to my questions in order to carry out the right execution of the program.

1) First, I try to test the model without integrating aspects of migration and habitat dependencies. I will assume fixed recruitment (see no relationship between stock and recruits based on the historical series) and conducted a cohort analysis (via VIT) to identify the initial recruitment number, will this number be appropriate ?

2) For the exploitation  fraction, I considered the fishing effort applied at the level of each fishing zone to specify it. My sub-regions are 28 different fishing zones where the activity takes place. The zone subject to the greatest fishing effort is that to which I have assigned a value of exploitation fraction 1 and on its basis I have concluded the exploitation fraction of the other regions.

3) Finally, my big doubt is about the dispersal of larvae in the model. I tried to establish it on the basis of the density of the individuals of age 0. Having some data on the abundance of the population, I performed an interpolation (using Qgis) to have an average density of each age (0 to 5+) in each sub-region. For the density result of age 0, considering the dispersion in each subregion as fraccion (density subregion x / total density of age 0 in the 28 subregions) will it be a good method for estimating the dispersion of larvae requiered ?


Thank you so much and sorry to have been a bit long. 


Post edited by Mery_kh on

Comments

  • Hi,

    We are corresponding over email.  I have followed up with the fisheries biologists who developed this model to get a more detailed answer to your questions.  I will email you and post the reply here as well when I have it.  Thanks for your patience!  Jess
  • Hi Meryeme, 

    I just send this to you over email, but will post on the forum as well.

    1) First, I try to test the model without integrating aspects of migration and habitat dependencies. I will assume fixed recruitment (see no relationship between stock and recruits based on the historical series) and conducted a cohort analysis (via VIT) to identify the initial recruitment number, will this number be appropriate ?

    This sounds right.
     2) For the exploitation  fraction, I considered the fishing effort applied at the level of each fishing zone to specify it. My sub-regions are 28 different fishing zones where the activity takes place. The zone subject to the greatest fishing effort is that to which I have assigned a value of exploitation fraction 1 and on its basis I have concluded the exploitation fraction of the other regions.
    This makes sense to me if you're assuming that all fishing zones have the same fish populations and you're trying to utilize catch information to back calculate the exploitation fraction.  Keep in mind that the exploitation fraction is the proportion of the population vulnerable to harvest that is actually harvested from 0-1 (0-100%) in each zone, and that each zone is independent.  It might be useful to take a look at how the sample data is formatted - the spiny lobster model from Belize example might be helpful.

    3) Finally, my big doubt is about the dispersal of larvae in the model. I tried to establish it on the basis of the density of the individuals of age 0. Having some data on the abundance of the population, I performed an interpolation (using Qgis) to have an average density of each age (0 to 5+) in each sub-region. For the density result of age 0, considering the dispersion in each subregion as fraccion (density subregion x / total density of age 0 in the 28 subregions) will it be a good method for estimating the dispersion of larvae requiered ?

    This makes sense to me.  If you look at the few sentences on Larval dispersion in the user's guide chapter you'll see we have estimated it a couple different ways (by available habitat in a region and by area of the subregion).  The citation for the Arkema, et al. paper (this is the Belize lobster example) has changed slightly (see below).  A sensitivity analysis here could be useful.

    Embedding ecosystem services in coastal planning leads to better outcomes for people and nature

    Arkema, Katie K ; Verutes, Gregory M ; Wood, Spencer A ; Clarke-Samuels, Chantalle ; Rosado, Samir ; Canto, Maritza ; Rosenthal, Amy ; Ruckelshaus, Mary ; Guannel, Gregory ; Toft, Jodie ; Faries, Joe ; Silver, Jessica M ; Griffin, Robert ; Guerry, Anne D

    Proceedings of the National Academy of Sciences of the United States of America, 16 June 2015, Vol.112(24), pp.7390-5
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