Grantee Research Project Results
2002 Progress Report: How Likely is it That Fish Populations Will Successfully Adapt to Global Warming?
EPA Grant Number: R829420E02Title: How Likely is it That Fish Populations Will Successfully Adapt to Global Warming?
Investigators: Klerks, Paul L. , Leberg, Paul L.
Institution: University of Louisiana at Lafayette
EPA Project Officer: Chung, Serena
Project Period: June 10, 2002 through June 9, 2004 (Extended to June 9, 2006)
Project Period Covered by this Report: June 10, 2002 through June 9, 2003
Project Amount: $121,598
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (2001) RFA Text | Recipients Lists
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)
Objective:
The objective of this research project is to investigate the likelihood that populations of fish will successfully adapt to temperature changes associated with global warming. This objective is being addressed for both normal populations and populations that have undergone a drastic reduction in size. A major factor determining the long-term ecological effects of global warming is whether organisms will be able to adapt to global warming. Successful adaptation would mean that global warming does not displace species from their current habitats. Distribution shifts and extinctions would occur if the organisms would fail to adapt to deleterious effects of global warming. At present, there is insufficient information to predict the evolutionary response of almost any species to climate change. The question is of special importance to the Southeastern United States, as organisms in warm waters already may be living close to their temperature tolerance limit, and because of the importance of fishery resources to the region's economy.
Progress Summary:
Selection Experiment
The selection is being done with normal populations and populations that have undergone drastic reductions in population size ("bottlenecked populations" that each started with a single pair of fish). We have established the greenhouse fish culturing facility (with 28 population trays and 14 filter tanks) and the 12 base populations (6 for the least killifish, Heterandria formosa, 6 for the western mosquitofish, Gambusia affinis). Each set of six populations started with fish from three different locations in Louisiana. At this point, we are waiting for the bottlenecked populations to reach a sufficient size to start the selection process (population size has to increase from 2 to 120 adults). The bottlenecked H. formosa populations almost have reached the desired size; the G. affinis populations are a bit smaller, as reproduction in this species started later in the spring than for H. formosa. We are close to completing the development of microsatellites to be used for quantifying the effect of the population bottlenecks on genetic variation. Polymerase chain reactions (PCR) amplification using a total of 20 pairs of primers based on 2 related species (Poeciilopis and Xiphophorus) showed that 11 pairs of these primers were consistently amplified in H. formosa. Currently, we are assessing variability of these primers in the least killifish. Microsatellite primers for the western mosquitofish were developed earlier (Spencer, et al., 2000).
Comparison of Temperature Tolerance Between Populations From Environments With Different Temperature Regimes
We have sampled about 12 sites in Florida, including sites receiving heated water from power plants, sites receiving cool or hot water from constant-temperature natural springs, and sites with an ambient thermal regime. Many of these sites did not have any least killifish, though the eastern mosquitofish (Gambusia holbrooki) generally was abundant at all sites. We have collected least killifish at two sites and eastern mosquitofish at four sites. We recently have completed the first heat-tolerance experiments with fish from these six populations, and are in the process of analyzing the data. Preliminary analyses indicate a lack of differences in temperature tolerance among the populations for each of the three pairs of sites with different thermal regimes.
Future Activities:
The activities to be undertaken in the next year are described in the following paragraphs.
Selection Experiment
We will continue this procedure. Once the bottlenecked populations have reached a population size of 120 adults (60 of each sex), 60 adults will be used as the founding population for each control and selection line. Offspring of these adults then will be exposed to elevated temperature to quantify resistance in generation 0 and to select the fish to be used as parents for the next generation for the selection line. Genetic variation will be compared (using microsatellites) between fish from the normal and bottlenecked populations (in generation 0), and between control and selection lines (in later generations, once resistance has evolved). We also will quantify the heritability of resistance in the 12 original (normal and bottlenecked) populations using standard quantitative genetics techniques.
Comparison of Temperature Tolerance Between Populations From Environments With Different Temperature Regimes
We will complete the comparison of temperature tolerance among Florida least killifish populations. If resistance differences are found, populations will be maintained for two generations and resistance compared again to determine whether the original differences in resistance were or were not genetically based. The same will be done for three sets of populations of the western mosquitofish. Moreover, because our Florida field observations indicate that the eastern mosquitofish may be especially capable of maintaining populations in extreme environments, we also are comparing temperature tolerance among different populations of this species.
Journal Articles:
No journal articles submitted with this report: View all 8 publications for this projectSupplemental Keywords:
global climate, ecological effects, vulnerability, aquatic, ecology, temperature, adaptation, genetic variation., RFA, Scientific Discipline, Air, Geographic Area, Hydrology, climate change, State, Environmental Monitoring, Atmospheric Sciences, Ecological Risk Assessment, wetlands, fish habitat, watershed, global change, Louisiana (LA), coastal ecosystems, aquatic ecology, global warming, land and water resources, climate variability, Global Climate ChangeRelevant Websites:
http://www.louisiana.edu/Departments/BIOL/klerks.html Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.