Event Title

Session D3: Drivers of Migratory Life Histories of Riverine Galaxias maculatus in Chile: Implications for Management

Location

Groningen, The Netherlands

Event Website

http://fishpassage.umass.edu/

Start Date

22-6-2015 4:45 PM

End Date

22-6-2015 5:00 PM

Description

Abstract:

A relationship between life histories and increasing latitude has been described for Northern Hemisphere riverine fish, whereby life cycles that complete most of the growth in the ocean are favoured at higher latitudes. In the riverine ecosystems of the Southern Hemisphere many species of galaxiids display highly flexible migratory life histories and the mechanisms driving employment of different strategies remain unclear. Our objective was to unravel the mechanisms driving the selection of migratory strategies of Galaxias maculatus from rivers across a gradient of latitude. Fifteen fish from three size classes as well as water samples were collected from upper, middle and lower sections of 10 river systems in Chile across latitudes 36°- 47°S. Otoliths and water samples were analysed for a suite of trace elements using Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Otolith elemental composition was analysed through depth profiling to assess the frequency of marine migrations in each section of each river. The propensity of marine migrations was strongly related to latitude as well as flow and temperature dynamics of each river system. Fish in river systems at higher latitudes more frequently displayed use of marine and brackish habitats, potentially enabling them to maximise foraging opportunities and increase recruitment success. River systems originating from large Andean lakes with more predictable flow pattern (large scale spring floodplain inundations and therefore more predictable food supplies) accommodated more resident individuals with no marine signatures even at higher latitudes. Therefore, climate as well as both longitudinal (headwaters-estuary) and lateral (main channel-floodplains) hydrologic connectivity seem to govern migratory strategies of riverine Galaxias maculatus.

Consequently, management strategies that promote both lateral and longitudinal connectivity within riverine ecosystems are crucial to maximise habitat availability for native fish species. (Financial support: Fondecyt 3130690, DIUC 213.310.063-1AP)

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Jun 22nd, 4:45 PM Jun 22nd, 5:00 PM

Session D3: Drivers of Migratory Life Histories of Riverine Galaxias maculatus in Chile: Implications for Management

Groningen, The Netherlands

Abstract:

A relationship between life histories and increasing latitude has been described for Northern Hemisphere riverine fish, whereby life cycles that complete most of the growth in the ocean are favoured at higher latitudes. In the riverine ecosystems of the Southern Hemisphere many species of galaxiids display highly flexible migratory life histories and the mechanisms driving employment of different strategies remain unclear. Our objective was to unravel the mechanisms driving the selection of migratory strategies of Galaxias maculatus from rivers across a gradient of latitude. Fifteen fish from three size classes as well as water samples were collected from upper, middle and lower sections of 10 river systems in Chile across latitudes 36°- 47°S. Otoliths and water samples were analysed for a suite of trace elements using Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Otolith elemental composition was analysed through depth profiling to assess the frequency of marine migrations in each section of each river. The propensity of marine migrations was strongly related to latitude as well as flow and temperature dynamics of each river system. Fish in river systems at higher latitudes more frequently displayed use of marine and brackish habitats, potentially enabling them to maximise foraging opportunities and increase recruitment success. River systems originating from large Andean lakes with more predictable flow pattern (large scale spring floodplain inundations and therefore more predictable food supplies) accommodated more resident individuals with no marine signatures even at higher latitudes. Therefore, climate as well as both longitudinal (headwaters-estuary) and lateral (main channel-floodplains) hydrologic connectivity seem to govern migratory strategies of riverine Galaxias maculatus.

Consequently, management strategies that promote both lateral and longitudinal connectivity within riverine ecosystems are crucial to maximise habitat availability for native fish species. (Financial support: Fondecyt 3130690, DIUC 213.310.063-1AP)

https://scholarworks.umass.edu/fishpassage_conference/2015/June22/67