I am studying Lake Tana Fisheries. Some species currently found under the IUCN list.
Some driving forces are irrigation and sand mining on their spawning grounds, overfishing, drought, waste from agriculture and urbanization, invasive species like water hyacinth. So, recently, some species are critically treated. I want to know the whole the species population structure from the lake, their status from their spawning grounds (tributary rivers), population dynamics, the extent of impact levels due to the above driving forces, population genetics from lake and rivers.
So, I am happy any one help me which type of models, methodology and share me your experience or any recent related works
You need to do a literature review to obtain as much empirical data as you can first, then identify what is lacking and focus your own research on that
Hi Gizachew Teshome
These are some ideas on how to know the behavior or structure in ichthyological communities. You have some identified environmental problems in your area of study. Your objetive is to demonstrate that these problems constitute the cause of the reduction of densities in different species of fish. I advise you to conduct a study of distribution and abundance in ichthyological populations in more affected and less affected or more conserved areas and to compare the densities of fish species between the areas. You can measure physical chemical parameters of water, because there are pollution problems. Conduct comparative studies between different times of the year to define the impact of drought periods. How to establish the sites with the highest incidence of the invasive species and compare with those less affected in terms of the abundance of the different ichthyological species. It is important to try to have information from previous studies.
These are some ideas that I hope will help you.
My opinion, in general terms:
1) You'll want to figure out how to quantify the anthropogenic factors you are interested in (i.e., overfishing, agricultural use, etc.) so you can evaluate them as potential explanatory variables. For the tributary rivers (if that is your scale of interest), you could quantify agricultural or urban land use by calculating the % of the catchment or riparian area bordering the tributary that consists of agricultural or urban land. To quantify irrigation effects, you could use the quantity of water abstracted (if that is available), percent water loss, or # of abstraction points. Invasive species: density per unit area of non-native taxa, or non-native to native taxa abundance ratio. Sand mining: number of mines or relative amount of sand extracted per tributary. Overfishing: average annual harvest (by weight or number) for each tributary.
2) You'll need to identify one or more response metrics such as fish density, fish average size, number of spawning pairs, average body condition, size spectra, or food-chain length that you believe will be affected by the habitat factors. Then you'll need to acquire data (historical or go to the field) to collect these metrics.
3) Test your hypotheses using a modelling framework suitable for your data.
You might find the papers I've attached useful: 1) we focused on the effects of water abstraction on fish assemblages and 2) the effects of catchment land cover on fish assemblages
I am less-versed in the genetics realm so I won't weigh in on what the approach should be for the population genetics aspect.
Hope that helps and good luck!
Many thanks for all your answers ( Enrique Reynaldo de la Cruz , Kevin M. Fraley)
- Badges
- Science method
- Similar topics
- Biological Science
- Ecology