I've read your proposal. There is one little mistake I noticed: PIT-tags are not external tags. They are internal as they are implanted intramuscular.
Now let's talk about the telemetry equippment:
We are using equipment from LOTEK http://www.lotek.com/
On there homepage you will find different types of tags (radio tags, acoustic tags and combined (radio-acoustic) tags). The big difference between radio and acoustic is that radio tags can be heard outside of the water using a receiver and an antenna. To hear radio signals it is very important that the water is not too turbid and not too deep because the turbidity in combination with water-depth "swallows" the radio signal. To give you an example: In the Danube we loose the radio signals when the fish is deeper than ~8 to 10m depending a bit on the turbidity. In the Mekong or the Songkram river we will loose the signal at even lower depth of a few meters as the turbidity there is much higher as I assume.
Acoustic tags can not be heard on air therefore you need to listen and search for them under water using a hydrophone and a receiver. With hydrophones the turbidity is not such a big problem. Therefore we will use acoustic tags or maybe combined tags. In this context there is one question I am interested in: How deep is the water in our study area on average?!
Next, we have to decide if we want to use any kind of sensor tags. Sensor tags are able to register and transmit data on (1) motion, (2) temperature, (3) pressure = water depth. My assumption is that we won't necessarily need sensor tags as we are doing a first study on the migration behaviour of the respective fish species. However, we still need to consider carefully if we could gain advantages from using sensor tags. In general this is not urgent and we can talk about it next Tuesday.
Next, we need to know the investigation period and also we need to know a little bit about the size of the fish we are going to tag. There are two general rules you need to know in this context: (1) the weight of the tag should not be higher than 2% of the weight of the fish (e.g. a fish with let’s say 500g weight will receive a tag with a maximum weight of 10g). (2) the weight and size of the tags is very much depending on the life span because bigger and heavier batteries mean longer life spans.
Can you give me an estimate about how long we are planning to investigate the migration? In our last meeting we have already been talking about that but I can’t remember what we have been deciding on?!
Next to the tags we will use 8 wireless hydrophones. The type of hydrophone depends on the types of tags we are using. To summarize: From today’s perspective we will apply coded acoustic tags and wireless hydrophones from LOTEK. For the data analysis we wont use special software except for ArcGIS just in case we want to illustrate maps. The data analysis will focus on migration distances, up- and downstream migration, migration periods, home range.
If you are interested we can meet on Tuesday before our meeting with Stefan and I can show you some results and pictures from our last telemetry studies and show you the equippment a little bit. This would also give us the chance to talk more in detail about the exact type of the tags we will use. The following questions need to be answered in the next steps to choose the right technology (tags):
How deep is the water on average?
Observation period?
Minimum size of the fish?
Next to the hydrophones - will there be time and chance to manually track the fish?