The programs of rescue and salvage of fish fauna during the construction of hydroelectric power plants are considered as a project management and not a science project in Brazil. Given the different geomorphological processes that formed the Brazilian basins, which methodologies, general management practices should be used for adapted local conditions? What method should be used to estimate the number and biomass of successfully rescued translocated individuals?
If you have a "quarantine" facility, the success in fish translocation can be determined by observing how prone the fish are to diseases during quarantine period. this can be quantified as the prevalence and the intensity of a particular disease. Animal transport (fish included) is usually associated with animal stress. During stress animals tend to have decreased immune system, thus more prone to diseases. Therefore, high disease prevalence may indicate lowered immune system and may be used as proxy to indicate stress levels. However, we have to make sure that the quarantine facility is in proper conditions to reduce bias, as the disease prevalence cannot be attributed to the poor quarantine conditions. The trick is to identify appropriate disease as indicators (fish parasites and ulcers are normally quite easy to observe) Another parameter that can be used is the survival rate of fishes during quarantine procedure. High survival rate indicates high success in adaptation, but the problem with this is that you will have mortality in your fish stock.
Very briefly (my son is waking up), some kind of hierarchical study using mark-recapture techniques (possibly supported with telemetry) across the different basins might help you understand what is going on. It is expensive and labour intensive, but should give you an idea of the proportion of individuals rescued.
You may want to undertake a systematic review of experimental and field studies to get a truly objective perspective. See cebc.bangor.ac.uk for more information about systematic review methodology
Dear,
I appreciate the attention. But the point is that we rescued when the cofferdam or grounding rivers are happening! There is no possibility to leave them in quarantine and we need to relocate them quickly with life. Underestimating're talking about 700.00 thousand individuals and about 50,000 pounds of various fish species!
graciously
Genetic mark recapture could get you there but you would have to capture a large number of juveniles to get enough "recaptures". Another confounding issue is how open is the system, if the adults survive to redistribute and their progeny are never recaptured, then did the parents die?
I think that PIT tags used in conjuction with acustic or radio telemetry tags would give you the best data. The PIT tags would diferentiate individual fish as well as mark groups (treatments, species, etc). You would have to install PIT tag arrays at the confluence of tributaries or at some determinant locations to give you a short and long term mortality rate. The telemtry would give disrtibution and behavior after release......
- Badges
- Science topic
- Similar topics
- Biological Science
- Zoology
- Ichthyology