scholarly journals Contribution of opsins and chromophores to cone pigment variation across populations of Lake Victoria cichlids

2021 ◽  
Author(s):  
Elodie Wilwert ◽  
Rampal S. Etienne ◽  
Louis Zande ◽  
Martine E. Maan
Keyword(s):  
Lake Victoria ◽  
Cone Pigment ◽  
Pigment Variation

scholarly journals Contribution of opsins and chromophores to cone pigment variation across populations of Lake Victoria cichlids

2021 ◽  
Author(s):  
Elodie Wilwert ◽  
Rampal S Etienne ◽  
Louis Van de Zande ◽  
Martine E Maan
Keyword(s):  
Lake Victoria ◽  
Expression Patterns ◽  
Cichlid Fish ◽  
Sympatric Species ◽  
Visual Sensitivity ◽  
Turbid Water ◽  
Cone Opsin ◽  
In The Wild ◽  
Environmental Causes ◽  
Pigment Variation

Adaptation to heterogeneous sensory environments has been implicated as a key parameter in speciation. Cichlid fish are a textbook example of divergent visual adaptation, mediated by variation in the sequences and expression levels of cone opsin genes (encoding the protein component of visual pigments). In some vertebrates including fish, visual sensitivity is also tuned by the ratio of Vitamin A1/A2-derived chromophores (i.e. the light-sensitive component of the visual pigment, bound to the opsin protein), where higher proportions of A2 cause a more red-shifted wavelength absorbance. Here, we explore variation in chromophore ratios across multiple cichlid populations in Lake Victoria, using as a proxy the enzyme CYP27C1 that catalyses the conversion of Vitamin A1- into A2. We focus on sympatric Pundamilia cichlids, where species with blue or red male coloration co-occur at multiple islands, but occupy different depths and consequently different visual habitats. In the red species, we found higher cyp27c1 expression in populations from turbid-water than from clear-water locations, but there was no such pattern in the blue species. Across populations, differences between the sympatric species in cyp27c1 expression had a consistent relationship with species differences in opsin expression patterns, but the red/blue identity reversed between clear- and turbid-water locations. To assess the contribution of heritable versus environmental causes of variation, we tested whether light manipulations induce a change in cyp27c1 expression in the laboratory. We found that cyp27c1 expression was not influenced by experimental light conditions, suggesting that the observed variation in the wild is due to genetic differences. Establishing the biological importance of this variation requires testing the link between cyp27c1 expression and A1/A2 ratios in the eye, as well as its consequences for visual performance.

GIS INTERPRETATION OF FOSSIL DISTRIBUTION OF AN EKEMBO BEARING SITE FROM THE EARLY MIOCENE, RUSINGA ISLAND, LAKE VICTORIA, KENYA

2018 ◽  
Author(s):  
Cindy L. Hendry ◽  
◽  
Kirsten E. Jenkins ◽  
Peter Li ◽  
Lauren A. Michel ◽  
...  
Keyword(s):  
Lake Victoria ◽  
Early Miocene ◽  
Rusinga Island

Hypoxia Tolerance in Twelve Species of East African Cichlids: Potential for Low Oxygen Refugia in Lake Victoria

1995 ◽  
Vol 9 (5) ◽  
pp. 1274-1288 ◽  
Author(s):  
LAUREN J. CHAPMAN ◽  
LESLIE S. KAUFMAN ◽  
COLIN A. CHAPMAN ◽  
F. ELLIS MCKENZIE
Keyword(s):  
Lake Victoria ◽  
Hypoxia Tolerance ◽  
Low Oxygen ◽  
East African ◽  
East African Cichlids ◽  
African Cichlids

Fish Price Determination Around Lake Victoria, Tanzania: Analysis of Factors Affecting Fish Landing Price

2021 ◽  
Vol 22 (2) ◽  
pp. 348-363
Author(s):  
Damian Boniface Sambuo ◽  
Stephen Kirama ◽  
Kitala Malamsha
Keyword(s):  
Lake Victoria ◽  
Regulatory Body ◽  
Price Determination ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Fish Market ◽  
Fishery Policy ◽  
The Government ◽  
And Performance

Determination of fish landing price is important, as the same contributes to the structure, conduct and performance of the fish market in Lake Victoria. Determination of relevant landing price is a gap to console between fishermen, agents (middlemen), processors and the government. The main objective of this study was therefore to examine fish price determination. Specifically, to examine the methods for fish price determination and analyse factors that affect fish landing price in Lake Victoria, a cross-sectional design was employed, and 300 respondents were randomly selected from two district councils, namely, Sengerema and Buchosa. Both qualitative and quantitative data were analysed using descriptive statistics and inferential analysis. Findings show that landing price is determined through formal negotiation with processors, consultation with other traders, informal negotiation with buyers and Beach Management Unit (BMU). The study concluded that these are the common methods used to determine landing prices. Also, distance from fishing to onshore landing centres, market information channels, age and experiences of the fishermen are the factors significantly found affecting landing price. It is recommended that the mechanism for setting up fishery price, fish market structure, fishery information and the formation of fishery regulatory body needs fishery policy and sector reforms that mark the determination of fish landing price.

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