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~: :i l' Secondary Altemative-hyporhesis- HAla: Indigenous and non-indigenous adult and sub-adult fish seek refuge in tributary mouths or other low velocity locations to avoid downstream displacement by high discharge events. Justification This hypothesis tests the premise that populations of sub-adult and adult indigenous and non-indigenous fishes in intuitive "refuge" areas (e.g., stream mouths, which are (I) ponded, low-velocity places in the system during high water in the mainstem and (2) far more accessible to sampling than the mainstem during flood) are statistically identical before, during, and following the discharge event, and further that any expected trend (e.g., an increase in numbers of fish seeking "refuge" during the event, thus resulting in a larger population sizes, unusual species' occurrence, etc., in the presumed "refuge" area) falls outside the variance of other data, collected at the same time of year by similar (comparable) techniques in other years (other things being as equal as possible). 14 ~ Methods Sampling of tributary mouths should be immediately (1-3 days) before u~ramping begins, once during the steady flow portion of the event, and at least twice afterward (one immediately [1-3 days] after down-ramping and the second no more than 10 days later). . ., Execution of the "experiment" should be done by the group who bas already compiled or can readily compile pre-experiment information. Distance from the dam should be considered. For example, fewer adult fishes (excluding trout) may be available to colonize the Paria River on short notice (thus "responding" to the flood by seeking "refuge") than adjacent to more downstream tributary mouths. The pwpose is to seek to explain equivocal resUlts, which certainly may obtain, on the basis of data rather than speculation. A minimum of five replicates (tributary mouths) should be sampled; 10 would be more desirable. , )~ - Bvuotheses Larval and Juvenile Fishes Null hypothesis 2- H02: Distnbution and abundance oflarval and juvenile fish will not be affected by a high discharge event Alternative hypothesis 2- HA2: Distribution and abundance of larval and juvenile fish are negatively affected by flooding as a result ofu~ to downstream displacement , :~~. ~* ~~:. Justification Displacement oflarval and juvenile fish downstream during flood is based on the assumption that these life-stages are unable to disperse into "refuge" areas or otherwise resist increased current velocity during flood. Studies during GeES I and GeES II have demonstrated 23