Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
San Francisco ◽  
Native Species ◽  
Larval Fish ◽  
Micropterus Salmoides ◽  
Early Life History ◽  
Drainage Water ◽  
Early Spring ◽  
Larval Fishes ◽  
Pogonichthys Macrolepidotus ◽  
History Of

<em>Abstract.</em>—We sampled larval fish in 1999 and 2001 on a restored floodplain along the lower Cosumnes River, California, from the onset of flooding to when the sites dried or when larval fish became rare. We collected more than 13,000 fish, of which prickly sculpin <em>Cottus asper </em>made up the majority (73%). Eleven species made up 99% of the catch. Three native fishes (prickly sculpin, Sacramento sucker <em>Catostomus occidentalis</em>, and splittail <em>Pogonichthys macrolepidotus</em>) and two alien species (common carp <em>Cyprinus carpio </em>and bigscale logperch <em>Percina macrolepida</em>) were associated with higher inundation and cool temperatures of early spring. In contrast, five alien taxa, sunfish <em>Lepomis </em>spp., largemouth bass <em>Micropterus salmoides</em>, crappie <em>Pomoxis </em>spp., golden shiner <em>Notemigonus crysoleucas</em>, and inland silverside <em>Menidia beryllina</em>, were associated with less inundation and warmer water temperatures. One native species, Sacramento blackfish <em>Orthodon microlepidotus</em>, was also associated with these conditions. Species did not show strong associations with habitat because of different spawning times of adults and expansion and contraction of flood waters. Most species could be found at all sites throughout flooded habitat, although river and floodplain spawning fishes usually dominated sites closest to levee breaches. Highest species richness was consistently found in two sloughs with permanent water because they both received drainage water from the floodplain and had a complement of resident species. Splittail, a floodplain spawner, was found primarily in association with submerged annual plants. Our results suggest that a natural hydrologic cycle in spring is important for providing flooding and cool temperatures important for many native larval fishes. Alien fishes are favored if low flows and higher temperatures prevail. Restoration of native fish populations that use floodplains for rearing should emphasize early (February–April) flooding followed by rapid draining to prevent alien fishes from becoming abundant.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
San Francisco ◽  
Striped Bass ◽  
Vertical Migration ◽  
Early Life ◽  
Life Histories ◽  
Early Life History ◽  
Small Surface ◽  
Delta Smelt ◽  
Larval Fishes ◽  
History Of

<em>Abstract.</em>—The goal of this study was to determine if the vertical distribution of larval delta smelt <em>Hypomesus transpacificus </em>and striped bass <em>Morone saxatilis </em>was affected by tidal stage and diel period. Delta smelt and striped bass have similar early life histories in that their larvae drift downstream from freshwater spawning habitats to brackish water rearing habitats. Little is known on whether the larvae undergo a vertical migration as they move downstream. Conical plankton nets were used to collect larval fishes from the surface, middle, and bottom sections of the main channels of the Sacramento and San Joaquin rivers. Samples were collected over six paired day–night cruises. Approximately 45,000 fish were collected; 82% were striped bass and 2% were delta smelt. More delta smelt were caught at night than during the day, and more at middle depth than surface or bottom. Very few striped bass were found at surface during day; most were caught at middle depth. Both species were fairly dispersed throughout the water column at night. Although striped bass larvae appear to undergo a small surface to middepth migration, this study indicates that larval delta smelt and striped bass do not undergo a mass diel or tidal vertical migration as they drift down the Sacramento and San Joaquin rivers.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
San Francisco ◽  
Sublethal Effects ◽  
Total Mortality ◽  
Early Life History ◽  
Toxicity Tests ◽  
Metabolic Dysfunction ◽  
Exposed Fish ◽  
Pogonichthys Macrolepidotus ◽  
History Of ◽  
Acute Toxicity Tests

<em>Abstract.</em>—Runoff from dormant spray applications to orchards can contain the insecticides diazinon and esfenvalerate, which may affect the health of the threatened splittail <em>Pogonichthys macrolepidotus</em>. To examine the potential effects of these two insecticides, splittail larvae were exposed to diazinon, esfenvalerate, and a mixture of the two insecticides in static renewal 96-h acute toxicity tests. Surviving fish were transferred to clean water for an additional 14 d (18 d total). Mortality, morphological anomalies, histopathology, and growth determinations were made to assess lethal and sublethal effects. The combination of diazinon and esfenvalerate produced less than additive (independent) toxicity. Diazinon (singly and in combination with esfenvalerate) produced latent toxicity after the 96-h exposure, as demonstrated by reduced growth and increased spinal deformities. Metabolic dysfunction in the liver and inflammation of the pancreas were likely related to slower growth of diazinon-exposed fish. These symptoms were almost absent from esfenvalerate-exposed fish. The use of 14-d EC50 values and the measurement of biomarkers may more accurately describe the effects of 96-h shortterm exposure to these insecticides than traditional 96-h LC50 values.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
San Francisco ◽  
Open Water ◽  
Early Life History ◽  
Spatial And Temporal Variability ◽  
Larval Rearing ◽  
Restored Wetlands ◽  
Marsh Edge ◽  
Reference Marsh ◽  
History Of ◽  
Native Fishes

<em>Abstract.</em>—We examined the spatial and temporal variability of native and alien ichthyoplankton in three habitat types (marsh edge, shallow open-water, and river channel) in one reference and three restored marshes in the Sacramento–San Joaquin Delta, California, during 1998 and 1999. More than 6,700 fish embryos and 25,000 larvae represented by 10 families were collected in 240 tows during the 2-year study. Overall, the assemblage was dominated by alien fishes, but natives were more abundant during winter and spring, whereas aliens were more abundant during summer. Overall abundance was highest in marsh edge habitats, suggesting that this habitat provides favorable larval rearing habitats for many fishes. The reference marsh was dominated by alien species making it difficult to assess whether it had attributes that promoted use by native fish. Ichthyoplankton abundance varied comparably at restored sites of similar configuration. The restored site, with minimal tidal exchange and greater lower trophic productivity, supported the highest densities of alien fish. We conclude that restoration projects in this region of the estuary must consider the potential impacts of alien fishes on natives and evaluate strategies designed to improve recruitment success of native fishes. Specifically, we suggest that restored wetlands that offer only winter and spring inundation periods may provide maximum benefits to natives while limiting access by many alien fishes regardless of specific habitat-use requirements.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
Growth Rate ◽  
San Francisco ◽  
Striped Bass ◽  
Growth Rates ◽  
Early Life History ◽  
San Francisco Estuary ◽  
Annual Growth ◽  
Factors Affecting ◽  
Juvenile Abundance ◽  
History Of

<em>Abstract.</em>—We investigated factors affecting growth of larval striped bass <em>Morone saxatilis </em>in the San Francisco Estuary from 1984 to 1993. We estimated ages and growth rates of larval striped bass from daily otolith increments. Mean annual growth rates of 6–14 mm standard length striped bass varied from 0.13 to 0.27mm/d, the lowest rate occurring in 1989 and the highest in 1992. The 1989 growth rate was significantly lower than all other years, and growth rates for 1992 and 1993 were significantly higher than all other years, but did not differ from one another. Differences in annual growth rates apparently were due mainly to differences in mean annual prey densities because growth rate increased as prey density increased. Compared to both laboratory measured growth rates and growth rates of field-caught Chesapeake Bay larvae, growth rates from the San Francisco Estuary appeared to be high for the food available, indicating that larvae can grow at relatively high rates even at low prey densities. Correlation analyses did not support density-dependent control of growth rates. Growth rate was not significantly related to mean annual conductivity, water temperature, mortality rates, or the juvenile abundance index, but was significantly and positively correlated with densities of 1-mm length-groups of 9–14-mm striped bass.

scholarly journals The early life history of fish—there is still a lot of work to do!

2014 ◽  
Vol 71 (4) ◽  
pp. 907-908 ◽  
Author(s):  
Howard I. Browman ◽  
Anne Berit Skiftesvik
Keyword(s):  
Life History ◽  
Early Life ◽  
Larval Fish ◽  
Fish Larvae ◽  
Early Life History ◽  
Life Stages ◽  
Early Life Stages ◽  
Relative Contribution ◽  
History Of ◽  
Fish Early Life Stages

Abstract The themed set of articles that follows this introduction contains a selection of the papers that were presented at the 36th Annual Larval Fish Conference (ALFC), convened in Osøyro, Norway, 2–6 July 2012. The conference was organized around four theme sessions, three of which are represented with articles in this collection: “Assessing the relative contribution of different sources of mortality in the early life stages of fishes”; “The contribution of mechanistic,behavioural, and physiological studies on fish larvae to ecosystem models”; “Effects of oil and natural gas surveys, extraction activity and spills on fish early life stages”. Looking back at the main themes of earlier conferences about the early life history of fish reveals that they were not very different from those of ALFC2012. Clearly, we still have a lot of work to do on these and other topics related to the biology and ecology of fish early life stages.

Scale-dependent variations in the precision of larval fish abundance estimates: a study of Sebastes sp. on Flemish Cap

1997 ◽  
Vol 54 (5) ◽  
pp. 1111-1120 ◽  
Author(s):  
P Pepin ◽  
J T Anderson
Keyword(s):  
Larval Fish ◽  
Sampling Period ◽  
Early Life History ◽  
Biological Processes ◽  
Relative Importance ◽  
Physical Processes ◽  
Pilot Studies ◽  
Abundance Estimates ◽  
History Of ◽  
Sampling Scale

We test the assumptions of synopticity over a 6-d sampling period and homogeneity within a 40 times 40 km stratum by investigating the effect of sampling scale, or station spacing, on the precision (i.e., variance) of abundance estimates of larval redfish (Sebastes sp.). We contrast the results obtained for larval redfish with observations of scale-dependent variability in temperature, salinity, chlorophyll, and zooplankton, which have been shown to be interrelated in other systems. In contrast with previous studies, our results show that the patterns of variance in temperature, salinity, chlorophyll, and zooplankton are not scale dependent. Although the assumption of synopticity cannot be rejected, our results show that the variance in abundance of larval redfish is scale dependent and that it is much greater than the variances of the other variables considered. The contrasting pattern may be due to differences in the relative importance of physical and biological processes during the very early life history of marine fish. We suggest that sampling programs must be preceded by pilot studies designed to determine the effort required to obtain the most precise estimates of abundance given the limitations caused by the underlying sampling variability and the influence of physical processes.

Status, Distribution, and Conservation of Native Freshwater Fishes of Western North America

2007 ◽  
Keyword(s):  
San Francisco ◽  
Early Spring ◽  
San Francisco Estuary ◽  
Central Component ◽  
Floodplain Restoration ◽  
Pogonichthys Macrolepidotus ◽  
Class Strength ◽  
Historical Levels ◽  
The U.S

ABSTRACT Splittail <em>Pogonichthys macrolepidotus</em>, a minnow native to the San Francisco Estuary, was originally listed by the U.S. Fish and Wildlife Service as threatened in 1999. The listing was remanded in 2003 based on recent evidence about its status and efforts to restore the species. Although young-of-year production declined during a 6-year drought prior to the listing, the return of wet conditions in the late 1990s resulted in record indices of abundance. Much of the minnow's historical off-channel habitat was lost by the early 1900s, but surveys suggest that the current range of splittail has stabilized. Year-class strength is directly related to the duration of inundation of remaining floodplain. Adults migrate upstream in winter or early spring to spawn on seasonally inundated vegetation. Their offspring rear in the food-rich floodplain habitat before emigrating with receding floodwaters. Based on the recognition that the species is perhaps one of the most floodplain-dependent fishes in the estuary, floodplain restoration became a central component of a major agency/stakeholder effort to fix long-standing problems in the region. Floodplain restoration is likely to substantially improve the long-term status of splittail, although extreme alterations in the food web from alien species may prevent the minnow from returning to historical levels.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
Life History ◽  
San Francisco ◽  
Early Life ◽  
Larval Fish ◽  
Early Life History ◽  
San Francisco Estuary ◽  
Pacific Herring ◽  
Body Depth ◽  
Frequency Distributions ◽  
Vertical Distributions

<em>Abstract.</em>—Pacific herring <em>Clupea pallasi </em>is a commercially and ecologically important fish with a sizable stock that spawns and spends its early life history in the San Francisco Estuary (SFE). Yet very little is known about the basic ecology of larval Pacific herring in the SFE. We undertook a 3-year field study (1999–2002), focused on winter and spring collections in two regions of the SFE (the Central and San Pablo bays), to address three objectives: (1) determine seasonal abundance patterns of larval Pacific herring in the two bays, (2) examine the diet of larval Pacific herring, and (3) evaluate the condition of larval Pacific herring in the two bays. Pacific herring were a conspicuous component of the winter larval fish assemblage in both the San Pablo and Central bays, comprising a maximum of 22.5% and 5.5% of total abundance, respectively. Larval Pacific herring abundance peaked in February or March of each year, reaching a maximum density of 2.53/m<sup>3 </sup>(San Pablo) and 0.52/m<sup>3 </sup>(Central Bay). Length frequency distributions suggested that at least 2–3 cohorts were produced each year, with some evidence that larvae were slightly larger in San Pablo Bay. Larval Pacific herring fed on a broad range of prey types, including tintinnids, copepodids, copepod nauplii, diatoms, and gastropod veligers. The unusually high proportion of tintinnids in the diet (87% by number in March 2001) suggests an important protozoan–metazoan linkage. Condition of larvae was assessed by analyses of covariance of a “growth sensitive” variable (i.e., body weight, anal body depth, or pectoral body depth) regressed against a “growth insensitive” variable (i.e., standard length). These results showed marked differences between the bays: in Central Bay, early (small) larvae exhibited better condition, but within San Pablo Bay, larvae exhibited a greater rate of improved condition with increasing age (size). This suggests the possibility of important differences in the Central and San Pablo bays as larval Pacific herring nursery grounds. Several areas of future research on the ecology of larval Pacific herring in SFE are recommended (e.g., coupling between horizontal and vertical distributions and advective flow fields, predation, and feeding dynamics on protozoan versus metazoan prey).

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
San Francisco ◽  
Fish Larvae ◽  
Light Trap ◽  
Early Life History ◽  
Light Sources ◽  
Light Traps ◽  
Natural Stream ◽  
History Of ◽  
Distribution And Ecology ◽  
Different Color

<em>Abstract.</em>—Light traps have been used to study the distribution and ecology of fish larvae in a variety of waters. Yet the physical and taxonomic limitations of light traps have been little studied, particularly in lotic systems. The purpose of this study was to examine aspects of light trap use, bias, and specificity in a natural stream setting. We sampled fish larvae using light traps in the upper Sacramento River watershed in April (2001, 2002) and June (2002) using five different color light sources and two trap sizes. Our results suggest that (1) small traps are as effective at sampling fish larvae as large traps, (2) color of light and/or relative intensity of light have strong effects on numbers of larvae collected, and (3) environmental factors play a role in the number of larvae collected over short time periods.

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