The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss
The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has...
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| Online Access: | http://hdl.handle.net/1957/35841 |
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ndltd-ORGSU-oai-ir.library.oregonstate.edu-1957-358412012-12-22T03:19:56ZThe influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykissOhms, Haleypartial migrationOncorhynchus mykissconditional strategylife historyRainbow trout -- Life cycles -- Oregon -- John Day RiverSteelhead (Fish) -- Life cycles -- Oregon -- John Day RiverRainbow trout -- Migration -- Oregon -- John Day RiverSteelhead (Fish) -- Migration -- Oregon -- John Day RiverRainbow trout -- Sex differences -- Oregon -- John Day RiverSteelhead (Fish) -- Sex differences -- Oregon -- John Day RiverRainbow trout -- Sex ratio -- Oregon -- John Day RiverSteelhead (Fish) -- Sex ratio -- Oregon -- John Day RiverThe evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory species Oncorhynchys mykiss (commonly known as steelhead and rainbow trout), I found that sex plays a strong role in whether an individual adopts an anadromous or resident life history. I observed a higher frequency of females adopting the anadromous tactic throughout the species range, and I attributed this to the relationship between body size and reproductive success in females that is not present in males. I did not observe differences in female bias along gradients of latitude or migration distance, and I hypothesize that while the frequency of tactics among populations may change along these gradients, either the change is equal between males and females, or an interaction of latitude and migration distance may control changes. I did not observe a corresponding male bias in the one resident population I sampled, and suggest that this is the result of a high frequency of residents in that population. I propose that sex ratios could be a valuable metric for measuring frequency of life-history tactics in populations and could facilitate the investigation into the controls of life-history tactics across broad scales.Graduation date: 2013Reeves, Gordon2012-12-21T19:24:08Z2012-12-21T19:24:08Z2012-12-102012-12-10Thesis/Dissertationhttp://hdl.handle.net/1957/35841en_USOregon Explorer |
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NDLTD |
| language |
en_US |
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NDLTD |
| topic |
partial migration Oncorhynchus mykiss conditional strategy life history Rainbow trout -- Life cycles -- Oregon -- John Day River Steelhead (Fish) -- Life cycles -- Oregon -- John Day River Rainbow trout -- Migration -- Oregon -- John Day River Steelhead (Fish) -- Migration -- Oregon -- John Day River Rainbow trout -- Sex differences -- Oregon -- John Day River Steelhead (Fish) -- Sex differences -- Oregon -- John Day River Rainbow trout -- Sex ratio -- Oregon -- John Day River Steelhead (Fish) -- Sex ratio -- Oregon -- John Day River |
| spellingShingle |
partial migration Oncorhynchus mykiss conditional strategy life history Rainbow trout -- Life cycles -- Oregon -- John Day River Steelhead (Fish) -- Life cycles -- Oregon -- John Day River Rainbow trout -- Migration -- Oregon -- John Day River Steelhead (Fish) -- Migration -- Oregon -- John Day River Rainbow trout -- Sex differences -- Oregon -- John Day River Steelhead (Fish) -- Sex differences -- Oregon -- John Day River Rainbow trout -- Sex ratio -- Oregon -- John Day River Steelhead (Fish) -- Sex ratio -- Oregon -- John Day River Ohms, Haley The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss |
| description |
The evolution and maintenance of multiple phenotypes within populations is an interesting evolutionary and ecological question, and is becoming increasingly important for the restoration and conservation of partially migratory species. In particular, why individuals adopt a particular phenotype has been the focus of numerous research efforts. In the partially migratory species Oncorhynchys mykiss (commonly known as steelhead and rainbow trout), I found that sex plays a strong role in whether an individual adopts an anadromous or resident life history. I observed a higher frequency of females adopting the anadromous tactic throughout the species range, and I attributed this to the relationship between body size and reproductive success in females that is not present in males. I did not observe differences in female bias along gradients of latitude or migration distance, and I hypothesize that while the frequency of tactics among populations may change along these gradients, either the change is equal between males and females, or an interaction of latitude and migration distance may control changes. I did not observe a corresponding male bias in the one resident population I sampled, and suggest that this is the result of a high frequency of residents in that population. I propose that sex ratios could be a valuable metric for measuring frequency of life-history tactics in populations and could facilitate the investigation into the controls of life-history tactics across broad scales. === Graduation date: 2013 |
| author2 |
Reeves, Gordon |
| author_facet |
Reeves, Gordon Ohms, Haley |
| author |
Ohms, Haley |
| author_sort |
Ohms, Haley |
| title |
The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss |
| title_short |
The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss |
| title_full |
The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss |
| title_fullStr |
The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss |
| title_full_unstemmed |
The influence of sex, migration distance, and latitude on expression of anadromy in Oncorhynchus mykiss |
| title_sort |
influence of sex, migration distance, and latitude on expression of anadromy in oncorhynchus mykiss |
| publishDate |
2012 |
| url |
http://hdl.handle.net/1957/35841 |
| work_keys_str_mv |
AT ohmshaley theinfluenceofsexmigrationdistanceandlatitudeonexpressionofanadromyinoncorhynchusmykiss AT ohmshaley influenceofsexmigrationdistanceandlatitudeonexpressionofanadromyinoncorhynchusmykiss |
| _version_ |
1716393834894589952 |