Hysterocarpus Research Articles

Tidal effects on marsh habitat use by three fishes in the San Francisco Estuary

Little is known about the ecological importance of low-order tidal marsh channels to fishes in the San Francisco Estuary, California. We conducted a passive mark-recapture study to compare residency, site fidelity, and movement patterns of fishes in a small intertidal channel (0.1 km2) in a large tidal marsh reserve (4.25 km2). We coupled continuous, high-frequency data on movements of fish tagged with Passive Integrated Transponder (PIT) tags and abiotic conditions from a PIT-detector and datasonde, respectively. Novel insights were gained by employing TidalTrend, a software program that characterizes tidal time-series data for ecological interpretation. Overall, we found that fishes exhibited different patterns of intertidal habitat use: the resident species, tule perch (Hysterocarpus traski), consistently spent more time per visit, per day, and per season using the intertidal channel, except during the reproductive window in spring; the transient species, Sacramento splittail (Pogonichthys macrolepidotus) and striped bass (Morone saxatilis), were more opportunistic and exhibited higher individual variation in movement patterns. Generalized additive mixed models indicated that tide height, rate of change in tide height, tidal inequality, time of day, lunar phase, and water temperature better predicted fish detections than other variables, but their effects varied across species. Based on our findings, we posit that time, through tides, allows habitat partitioning among fish species and individuals with different life-history types. Furthermore, functional connectivity between subtidal and intertidal channels in tidal marshes is a feature of the estuarine mosaic that should be integrated into habitat restoration designs in the San Francisco Estuary.

Estuarine-terrestrial habitat gradients enhance nursery function for resident and transient fishes in the San Francisco Estuary

Nursery functions of US West Coast drowned river valley estuaries are not well understood. Using long-term fish-monitoring data (1995-2017) in Suisun Marsh, San Francisco Estuary, California, USA, we examined spatial and temporal trends in abundance and apparent growth of fishes with diverse life-history types. Focal species were Sacramento splittail Pogonichthys macrolepidotus, striped bass Morone saxatilis, tule perch Hysterocarpus traski, and starry flounder Platichthys stellatus, which collectively represented 55% of total catch (n = 140092). We identified keystone habitat patches that functioned as nursery hotspots during the peak young-of-the-year recruitment window. Deep, flow-through sloughs close to the open estuary were important nursery habitats for the marine transient starry flounder. In contrast, splittail and striped bass mostly migrated through such corridors to rear in shallow, dead-end sloughs bisecting tidal marsh plains, managed tidal ponds, and uplands. Tule perch were concentrated in shallow, interior sloughs, reflecting their resident life-history type and adaptations to variable conditions in a small home range. Interactions among freshwater flows and stationary habitat features (e.g. channel depth, land-to-open-water ratio) were related to fish abundance; however, species and age classes differed in their relationships to these interactions, suggesting a mechanism for habitat partitioning in space and time. Overall, we inferred that habitat connectivity—longitudinal, lateral, and vertical—along the estuarine-terrestrial gradient was a driver of fish species diversity and productivity. Consideration of seascape-landscape dynamics across multiple spatial and temporal scales in estuaries should help maintain or increase fish populations and ecological resilience in the face of rising sea levels and other environmental stressors.

Sexual Dimorphism and Size-Related Changes in Body Shape in Tule Perch (Family: Embiotocidae), a Native California Live-Bearing Fish

The Tule Perch, Hysterocarpus traskii, is a viviparous and externally monomorphic, internally fertilizing fish. Despite appearing monomorphic, males and females are expected to differ in body shape because the different reproductive roles occupied by the sexes should influence patterns of selection and, ultimately, lead to differences in morphology. The objectives of this study were to determine if the Sacramento–San Joaquin subspecies of Tule Perch (H. t. traskii) exhibit (1) sexual dimorphism in body shape, (2) size-related changes in body shape, and (3) sexual size dimorphism. Geometric morphometric analyses indicated that H. t. traskii exhibited significant sexual dimorphism of body shape and identified the mid-body and caudal peduncle regions as the most effective discriminators between the sexes. Females were narrower through the caudal peduncle and mid-body and had anal-fin origins that were more posteriorly located than males. Additionally, H. t. traskii exhibited significant size-related changes in body shape. Larger fish were deeper bodied with blunter snouts and wider caudal peduncles. The eyes of larger fish were relatively smaller and located higher on the body than those of smaller fish. Hysterocarpus t. traskii did not exhibit differences between the sexes in standard length, but males were significantly heavier than females.

Molecular Evidence for Multiple Paternity in a Population of the Viviparous Tule Perch Hysterocarpus traski

Population density might be an important variable in determining the degree of multiple paternity. In a previous study, a high level of multiple paternity was detected in the shiner perch Cymatogaster aggregata, a species with high population density and a high mate encounter rate. The tule perch Hysterocarpus traski is phylogenetically closely related to C. aggregata, but it has relatively lower population density, which may result in distinct patterns of multiple paternity in these 2 species. To test the hypothesis that mate encounter rate may affect the rate of successful mating, we used polymorphic microsatellite markers to identify multiple paternity in the progeny arrays of 12 pregnant females from a natural population of tule perch. Multiple paternity was detected in 11 (92%) of the 12 broods. The number of sires per brood ranged from 1 to 4 (mean 2.5) but with no correlation between sire number and brood size. Although the brood size of tule perch is considerably larger than that of shiner perch (40.7 vs. 12.9, respectively), the average number of sires per brood in tule perch is much lower than that in shiner perch (2.5 vs. 4.6, respectively). These results are consistent with the hypothesis that mate encounter rate is an important factor affecting multiple mating.

Archaeological Perspectives on Native American Fisheries of California, with Emphasis on Steelhead and Salmon

AbstractThe archaeological record of California was surveyed to gain an understanding of Native American fisheries and to locate the prehistoric distributions of freshwater and anadromous fishes. Over 152,000 piscine elements were added to prior totals. On San Francisco Bay, important prehistoric intertidal fisheries were especially well documented for bat rays Myliobatis californica, sturgeons Acipenser spp., Chinook salmon Oncorhynchus tshawytscha, clupeids, and atherinopsids. The same sites also indicate the former presence of various freshwater species, including steelhead O. mykiss and coho salmon O. kisutch, in tributary streams from which they were extirpated prior to modern surveys. Slow‐moving waters of the Central Valley were heavily exploited, with most sites dominated by Sacramento perch Archoplites interruptus, thicktail chub Gila crassicauda, Sacramento suckers Catostomus occidentalis, Sacramento blackfish Orthodon microlepidotus, hitch Lavinia exilicauda, and tule perch Hysterocarpus traski, which collectively comprised 84.9% of the remains. Sacramento perch alone produced 45.7% of the identifiable elements. Noteworthy among the other identified species was the endangered delta smelt Hypomesus transpacificus. Salmonids Oncorhynchus spp. constituted only 6.3% of the remains from the Central Valley, despite their importance in the ethnographic record. Marine fishes were found far from the coast in San Diego, Monterey, and Kern counties. Freshwater species transported from the San Joaquin Valley were found as far eastward as San Bernardino County in the Mojave Desert. Steelhead were found among archaeological materials of coastal California as far south as Los Peñasquito Creek in San Diego County, but no salmon remains of any kind were found south of San Francisco. Too little sampling has been completed from coastal sites between San Francisco and Monterey Bay to rule out salmonid presence at locations where habitat was appropriate and where early reports indicated their existence. Chinook salmon were the most abundant salmonid in the Sacramento River drainage. No salmonids were found in the archaeological record in the San Joaquin River drainage south of San Joaquin County. Elements identifiable as either rainbow trout O. mykiss or cutthroat trout O. clarki were found in middens in the Lahontan system and in headwater streams of the Pit River in northeastern California. The rarity of salmonids in archaeological materials suggests that the ethnographic record overstated the importance of salmonids to the Native Americans of California and dramatically understated the importance of the Sacramento perch and its associated fauna.

Fish community structure and environmental correlates in the highly altered southern Sacramento-San Joaquin Delta

We sampled 11 sites in the southern Sacramento-San Joaquin Delta from 1992–1999, to characterize fish communities and their associations with environmental variables. Riparian habitats were dominated by rock-reinforced levees, and large water diversion facilities greatly influenced local hydrodynamics and water quality. We captured 33 different taxa, only eight of which were native. None of the native species represented more than 0.5% of the total number of individuals collected. The abundance of native species was consistently low but typically peaked during high outflow periods. Fish communities were predominantly structured along environmental gradients of water temperature and river flow. Native species (tule perch, Hysterocarpus traski, & Sacramento sucker, Catostomus occidentalis) were associated with conditions of high river flow and turbidity, while the majority of the non-native species were associated with either warm water temperature or low river flow conditions. The exceptions were the non-native striped bass, Morone saxatilis, and white catfish, Ameiurus catus, which were positively associated with relatively high river flow. Variation in fish community structure was greater among river locations within years than within river locations among years, thus fish communities at each river location were consistently different each year. Differences in fish communities among river locations were correlated with river flow and turbidity. We predict that the fish communities of this region will remain numerically dominated by non-native species if the environmental conditions we observed persist in the future.

Microhabitat Use by an Assemblage of California Stream Fishes: Developing Criteria for Instream Flow Determinations

Microhabitat requirements were determined for eight species of native California stream fishes: Rainbow trout Salmo gairdneri; Sacramento sucker Catostomus occidentalis; Sacramento squawfish Ptychocheilus grandis; hardhead Mylopharodon conocephalus; California roach Hesperoleucus symmetricus; speckled dace Rhinichthys osculus; tule perch Hysterocarpus traski; and riffle sculpin Cottus gulosus. Two or three size classes were evaluated for each species. Each species had a preferred microhabitat (defined on the basis of depth, velocity, substrate), as did each size class within each species, but there was much similarity in microhabitat use within and among species. The amount of microhabitat available to each species differed in three stream reaches in which availability was quantified, but the differences were not enough to explain the differences in composition of the fish assemblage found at each site. This study indicates that recommendations for instream flows should be based on microhabitat use data collected on site together with habitat availability data. Even on-site data should be used cautiously because intraspecific interactions and changes in a streamˈs physical characteristics, especially in its temperature regime, may cause unexpected shifts in microhabitat use.

Life history characteristics of tule perch (Hysterocarpus traski) populations in contrasting environments

The life history characteristics of tule perch were compared within and among populations in three drainages with substantially different environmental conditions. Within populations there were, in general, substantial increases in brood size, size of young, brood weight, and gonadal-somatic index (GSI) with age and with size of female. In at least one population there was a trade-off between the number and size of young produced. However, in a lake where individual growth was very slow, brood weight, GSI, and other life history characters showed decreasing trends with age. Among populations in isolated drainages, female length at first reproduction and longevity varied directly and mean brood size varied inversely with environmental predictability. Morphological and geological evidence and some comparative litter characteristics suggest that life history differences among populations in isolated drainages are in part genetic.

Morphometric Analysis of Tule Perch (Hysterocarpus traski) Populations in Three Isolated Drainages

Morphometric analysis of tule perch from six sites in three isolated drainages was conducted to assess the validity of previous systematic work. Nine variables were subjected to principal component and discriminant analysis. Principal component analysis indicated that groupings by drainage were real. Classification by discriminant functions among drainages was 96% accurate. Classification among collection sites was less accurate (88% overall), but most misclassified cases were assigned to another site in the same drainage. Ecophenotypic variation was apparent but the degree of overlap between drainages was minimal and indicated that the within-drainage differences were less than the among-drainage differences. Our analysis supports the view that populations in separate drainages are sufficiently distinct to warrant subspecific designation. T HE tule perch (Hysterocarpus traski) is the only exclusively freshwater member of the surfperch family (Embiotocidae) and is confined to three drainages in central California. It is unique among the freshwater fauna of California in that it is the only native viviparous fish. One population is largely confined to two lakes in the Clear Lake drainage basin, another is confined to the Russian River, a large coastal stream, and the third is found in a wide variety of habitats in the Sacramento-San Joaquin drainage including small tributary streams, main river channels, impoundments, and sloughs in the Sacramento-San Joaquin Estuary. Hopkirk (1962, 1973) recognized the populations in each drainage as morphological subspecies but Hubbs (1974) questioned Hopkirk's findings, mostly on the basis of his methodol

Late-Pleistocene and Holocene remains of Hysterocarpus traski (Tule Perch) from Clear Lake, California, and inferred Holocene temperature fluctuations

The remains of scales of Hysterocarpus traski Gibbons (Tule perch) were found throughout a 27.44-m core from Clear Lake. Most scales occurred between the mud surface and deposits approximately 11,000 years old. Changes in growth rates of the animals were examined by measuring scale annuli and applying an empirically established regression of fish length on scale radius. The data indicate a pattern of accelerating growth rates, reaching a peak between ⋍4000 and 2800 BP. After ⋍2800 BP, growth rates decline markedly. Because the growth rates of these animals are essentially dependent on temperature, the changes observed in the patterns of growth probably reflect changes in climate in the northern Coast Range. The general pattern of inferred temperature increase during the early and middle Holocene, ending between ⋍4000 and 2800 BP, is consistent with evidence from tree-line studies and palynology indicating higher temperatures in parts of the western United States during this period.