Questions

Is the timing of estuarine/marine entry and nearshore-offshore distribution of juvenile salmon synchronized among regions in Puget Sound?

Knowledge of timing and distribution of organisms is a critical precursor for understanding the relative use or importance of specific regions (e.g., sub-basins of Puget Sound) and zones (e.g., inner and outer estuary, nearshore marine and offshore marine zones within all regions of Puget Sound) for different species and life history stages of salmon through time. This information brackets when and where juvenile salmon utilize different spatial-temporal cells and helps identify the associated environmental conditions and biotic interactions that potentially influence their performance (growth and survival) and duration of remaining in these areas.
If all juveniles of a given species simultaneously enter estuarine/marine waters, then we have a convenient general trend that is spatially and temporally representative of all regions in the Sound that would simplify subsequent analyses regarding their habitat utilization, performance, and interactions during their early marine life history. Such synchrony would suggest that estuarine/marine entry was timed to optimize the use of critical resources that are available and change simultaneously throughout the Sound (or perhaps freshwater rearing conditions degrade uniformly across all watersheds). Has human disturbance altered the timing and availability of critical resources? If so, has this created a temporal-spatial mismatch in juvenile salmon performance throughout Puget Sound or in localized areas? We need the general overall picture of temporal distribution patterns throughout Puget Sound in order to identify and interpret localized deviations from the “normal” pattern. If timing differs markedly among regions or stocks within regions, this suggests that local adaptation is important and has implications for current and future performance of juveniles.

Do temporal patterns in size structure or growth of identifiable stocks of juvenile salmon differ among regions and zones of Puget Sound?

Length frequency histograms and mean (SD) length and/or weight estimates for the general pool of juveniles sampled at each temporal-spatial cell can generate patterns for comparison to data for identifiable stocks (e.g., from CWT or otolith-marked cohorts of fish). Of particular interest is whether fish from relatively concurrent beach seine, surface tow net, purse seine, or midwater trawl differ significantly in size structure within or among regions in Puget Sound. Most comparisons would involve the beach seining and tow netting data from NOAA-Fisheries, Casey Rice; Skagit Coop. Eric Beamer; USGS, Reg Reisenbichler; and opportunistic pairings with other groups in Puget Sound, especially during 2002 and 2003 (e.g., NOAA-Fisheries, Mindy Rouse; UW Dave Beauchamp & Liz Duffy). However a few valuable comparisons should be available between beach seine, tow net, Purse seining (~June 20-28, 2003 in Possession Sound), and beach seining, tow netting, and midwater trawling by the R/V Ricker in July or September for most years from 1995-2002). We’ll need to consider effect of size-selective sampling among and within gear types. A good opportunity for this will be to compare length frequencies among concurrent beach seine, tow net, and purse seine samples in Possession Sound during late June 2003.

Do temporal or size-specific patterns in diet composition differ among zones or regions in Puget Sound?

Although not as common as the temporal catch and distribution data, diet samples were collected across enough regions of Puget Sound, particularly in 2001, 2002, or 2003 to generate a reasonable comparison of spatial patterns in diet composition among regions. The key response variable for this analysis would be the weight proportion of key prey types among estuarine, nearshore and offshore zones within each region and for diets among regions for each zone.

Do the density, size structure or diet of predatory salmonids (especially sea-run cutthroat trout and char) differ among regions of Puget Sound?

We expect that much less and more variable data exist for these known piscivores. Nonetheless, CPUE and size data can contribute to whether potential predation pressure varies markedly among regions of Puget Sound. Sparse diet samples and data from various studies could become valuable when consolidated into a broad examination of patterns in Puget Sound.



PS Salmon Synthesis Working Questions Meetings Next Steps People & Projects Links	Juvenile salmon in Puget Sound Synthesis of current research Spatial Generality in Timing, Distribution, and Growth Patterns: Is the timing of estuarine/marine entry and nearshore-offshore distribution of juvenile salmon synchronized among regions in Puget Sound? Knowledge of timing and distribution of organisms is a critical precursor for understanding the relative use or importance of specific regions (e.g., sub-basins of Puget Sound) and zones (e.g., inner and outer estuary, nearshore marine and offshore marine zones within all regions of Puget Sound) for different species and life history stages of salmon through time. This information brackets when and where juvenile salmon utilize different spatial-temporal cells and helps identify the associated environmental conditions and biotic interactions that potentially influence their performance (growth and survival) and duration of remaining in these areas. If all juveniles of a given species simultaneously enter estuarine/marine waters, then we have a convenient general trend that is spatially and temporally representative of all regions in the Sound that would simplify subsequent analyses regarding their habitat utilization, performance, and interactions during their early marine life history. Such synchrony would suggest that estuarine/marine entry was timed to optimize the use of critical resources that are available and change simultaneously throughout the Sound (or perhaps freshwater rearing conditions degrade uniformly across all watersheds). Has human disturbance altered the timing and availability of critical resources? If so, has this created a temporal-spatial mismatch in juvenile salmon performance throughout Puget Sound or in localized areas? We need the general overall picture of temporal distribution patterns throughout Puget Sound in order to identify and interpret localized deviations from the “normal” pattern. If timing differs markedly among regions or stocks within regions, this suggests that local adaptation is important and has implications for current and future performance of juveniles. Do temporal patterns in size structure or growth of identifiable stocks of juvenile salmon differ among regions and zones of Puget Sound? Length frequency histograms and mean (SD) length and/or weight estimates for the general pool of juveniles sampled at each temporal-spatial cell can generate patterns for comparison to data for identifiable stocks (e.g., from CWT or otolith-marked cohorts of fish). Of particular interest is whether fish from relatively concurrent beach seine, surface tow net, purse seine, or midwater trawl differ significantly in size structure within or among regions in Puget Sound. Most comparisons would involve the beach seining and tow netting data from NOAA-Fisheries, Casey Rice; Skagit Coop. Eric Beamer; USGS, Reg Reisenbichler; and opportunistic pairings with other groups in Puget Sound, especially during 2002 and 2003 (e.g., NOAA-Fisheries, Mindy Rouse; UW Dave Beauchamp & Liz Duffy). However a few valuable comparisons should be available between beach seine, tow net, Purse seining (~June 20-28, 2003 in Possession Sound), and beach seining, tow netting, and midwater trawling by the R/V Ricker in July or September for most years from 1995-2002). We’ll need to consider effect of size-selective sampling among and within gear types. A good opportunity for this will be to compare length frequencies among concurrent beach seine, tow net, and purse seine samples in Possession Sound during late June 2003. Trophic Interactions Do temporal or size-specific patterns in diet composition differ among zones or regions in Puget Sound? Although not as common as the temporal catch and distribution data, diet samples were collected across enough regions of Puget Sound, particularly in 2001, 2002, or 2003 to generate a reasonable comparison of spatial patterns in diet composition among regions. The key response variable for this analysis would be the weight proportion of key prey types among estuarine, nearshore and offshore zones within each region and for diets among regions for each zone. Do the density, size structure or diet of predatory salmonids (especially sea-run cutthroat trout and char) differ among regions of Puget Sound? We expect that much less and more variable data exist for these known piscivores. Nonetheless, CPUE and size data can contribute to whether potential predation pressure varies markedly among regions of Puget Sound. Sparse diet samples and data from various studies could become valuable when consolidated into a broad examination of patterns in Puget Sound.
Send mail to: ejduffy@u.washington.edu Last modified: 1/26/2006 2:35 PM