RESTOCKING LAKE MALAWI MAY BE PRE-MATURE

Chambo Fisheries a Blantyre based fish farming industry says restocking Lake Malawi is possible as in the following article of 14 October 2014 in Nation News Paper:

http://mwnation.com/chambo-fisheries-says-can-restock-lake-malawi-chambo/

What Malawians should know is that there is a scientific backed frame work which is called Chambo Restoration Plan. Before the over-zealous journalist and individuals indulge into such complex undertakings they have to do their home work well. A restoration process of the Lake or River as id done in some of the world as is quoted in the paper is not the same as dumping trush fish into a natural habitat. A lot of thinking has to go through this process, most and first of all is the genetic impact the new populations are going to have on the receiving populations, the behavior and survival mechanism of the introduced populations after being domesticated and genetically being manipulated as a population itself. the way the story has been portrayed is as if, what is lacking are the number of seed fish also ka fingerlings in aquatic field. No fingerlings is not the issue and even the company claiming to have the numbers.

Journalist can do better to contact National Aquaculture Centre, a government institution which has the mandate and authority to do such kind of work in any country in the World.

Climate change and genetic variability through hybridization process in fish species

This is a fascinating article which has linked climate change and genetic variability through hybridization between an invasive and native fish species in USA. The research work has been published in nature climate change.

Read the following extract from site http://www.usgs.gov/newsroom/article.asp?ID=3903#.U45RHXKSySo

"In the study, stream temperature warming over the past several decades and decreases in spring flow over the same time period contributed to the spread of hybridization between native westslope cutthroat trout and introduced rainbow trout – the world’s most widely introduced invasive fish species –across the Flathead River system in Montana and British Columbia, Canada.

Experts have long predicted that climate change could decrease worldwide biodiversity through cross-breeding between invasive and native species, but this study is the first to directly and scientifically support this assumption. The study, published today in Nature Climate Change, was based on 30 years of research by scientists with the U.S. Geological Survey, University of Montana, and Montana Fish, Wildlife & Parks.

Hybridization has contributed to the decline and extinction of many native fishes worldwide, including all subspecies of cutthroat trout in western North America, which have enormous ecological and socioeconomic value.  The researchers used long-term genetic monitoring data coupled with high-resolution climate and stream temperature predictions to assess whether climate warming enhances interactions between native and nonnative species through hybridization.

“Climatic changes are threatening highly prized native trout as introduced rainbow trout continue to expand their range and hybridize with native populations through climate-induced ‘windows of opportunity,’ putting many populations and species at greater risk than previously thought,” said  project leader and USGS scientist Clint Muhlfeld. “The study illustrates that protecting genetic integrity and diversity of native species will be incredibly challenging when species are threatened with climate-induced invasive hybridization.”

Westslope cutthroat trout and rainbow trout both spawn in the spring and can produce fertile offspring when they interbreed. Over time, a mating population of native and non-native fish will result in only hybrid individuals with substantially reduced fitness because their genomes have been infiltrated by nonnative genes that are maladapted to the local environment. Thus, protecting and maintaining the genetic integrity of native species is important for a species’ ability to be resilient and better adapt to a rapidly changing climate.  

Historical genetic samples revealed that hybridization between the two fish species was largely confined to one downstream Flathead River population. However, the study noted, over the past 30 years, hybridization rapidly spread upstream, irreversibly reducing the genetic integrity of native westslope cutthroat trout populations. Genetically pure populations of westslope cutthroat trout are known to occupy less than 10 percent of their historical range.

The rapid increase in hybridization was highly associated with climatic changes in the region. From 1978 to 2008 the rate of warming nearly tripled in the Flathead basin, resulting in earlier spring runoff, lower spring flooding and flows, and warming summer stream temperatures. Those locations with the greatest changes in stream flow and temperature experienced the greatest increases in hybridization. 

Convention on Biological Diversity

Had a good time attending a 5th country report on Convention on Biological Diversity and be able to make fisheries and aquatic diversity.