CONSERVATION
CONSERVATION
Population Status and Ecology of Brown Trout: Rio Grande, Tierra del Fuego, Argentina, 2007 season.
During the 2006 angling season, Nervous Waters of Argentina (NWA), Estancia Maria
Behety (EMB), Frontiers Travel, and The Fly Shop contracted the Flathead Lake Biological Station (FLBS) and the University of Montana to begin a scientific assessment of the economically important sea trout population in the Rio Grande of Tierra del Fuego. The goals of the project are to understand:
1) The status of the brown trout population,
2) The effect of sport fishing on population structure and productivity,
3) What factors, other than angling, may limit trout productivity in different reaches of the river system.
Year 2006
The study entailed two major parts. The first involved working with NWA and EMB fishing guides and clients to collect mark-recapture data as well as size data, scale, tissue, and some stomach content samples from the adult sea run brown trout population. These data taken over several years will allow us to demonstrate the size, age and genetic structure of the population, including resident and sea run (anadromous) forms, and mortality associated with angling. The second part of the study concerned the basic ecology of the river, including the importance of various main channel, floodplain and tributary habitats for growth and survival of brown trout. This involved electrofishing to determine spatial distribution of juvenile and resident brown trout and collection of temperature, water chemistry, and food web data as basic river indicators and, hence, trout productivity. We present herein preliminary results from our first year of study (Read more).
Year 2007
This year’s work entailed three major parts. The first part concerned the basic ecology of the river, including the importance of main channel, floodplain and tributary habitats for growth and survival of brown trout. This involved collection of physical habitat, temperature, water chemistry, and food web data as basic indicators of river health, as as electrofishing to determine the spatial distribution of juvenile and resident brown trout in light of these data.
The second part of the study involved working with NWA and EMB fishing guides and clients to collect mark-recapture data, as well as size data and scale samples from the adult sea run brown trout population. These data taken over several years will allow us to determine the size and age structure of the population as well as mortality rates. Additionally, this year we compiled available historical records in order to understand population cycles during the past seventeen years. We present herein preliminary results from our second year of study (Read more).
Year 2008
This year’s work entailed two major parts. The first part concerned continued data collection of the basic ecology of the river. In 2008, this involved collection of temperature data and electrofishing to determine the spatial distribution of juvenile and resident brown trout in light of data previously collected in 2006 and 2007. The second part of the study involved continued work with NWA and EMB fishing guides and clients to collect mark-recapture data as well as size data and scale samples from the adult sea run brown trout population. These data taken now over three years allow us to estimate the size and age structure of the population as well as mortality rates. We present herein results from the third year of study (Read more).
