River Striped Bass Morone Saxatilis Research Articles

Coastal Migration and Homing of Roanoke River Striped Bass

AbstractAnadromy in Roanoke River Striped Bass Morone saxatilis has been documented; however, the specifics of the ocean migration and the degree of homing in this population remain unstudied and would greatly benefit the management of this economically important species. To this end, we telemetered and released 19 large Roanoke River Striped Bass (750–1,146 mm TL) on their spawning grounds during the springs of 2011 and 2012. Data from a large‐scale acoustic telemetry array along the U.S. Atlantic coast (480 total receivers, including the Roanoke River) were used to evaluate the seasonal migration and distribution of telemetered fish, their degree of homing and skipped spawning, their migration speeds, and the environmental drivers of migration timing. We found that large Roanoke River Striped Bass (>900 mm TL) rapidly emigrated (~59 km/d) after spawning to distant (>1,000 km) northern ocean waters (New Jersey to Massachusetts), where they spent their summers. They then migrated southward in the fall to overwintering habitats off Virginia and North Carolina and completed their migration circuit the following spring by returning to the Roanoke River to spawn. Our results showed no evidence of straying or skipped spawning, as all migrants successfully returned (homed) to the Roanoke River the next spring to spawn. Cooler ocean water temperatures in 2013 delayed the spring spawning run by nearly 3 weeks relative to a year of average spring temperatures (2012). Our study provides novel information that aids the management of Striped Bass at both small (e.g., setting of fishing seasons in the Roanoke River) and large spatial scales (e.g., stock identification of Roanoke River fish in the mixed‐stock ocean fishery) and more broadly highlights the utility of large‐scale cooperative telemetry arrays in studying fish migration.Received February 5, 2015; accepted May 27, 2015

Intercept Telemetry of the Hudson River Striped Bass Resident Contingent: Migration and Homing Patterns

AbstractHudson River striped bass Morone saxatilis show highly variable migration patterns, as observed through past tagging studies and otolith microchemical analyses. Recent studies have shown resident, estuarine, and ocean migratory contingents in the Hudson River. We undertook a directed study to more precisely characterize the seasonal migrations of the resident contingent. Remote biotelemetry was conducted on 12 resident striped bass during a 14‐month period in 2004–2005. All tagged striped bass migrated downriver from October 2004 to January 2005 and returned upriver from March to May 2005. Observed seasonal migration patterns were similar to those expected from previous tagging and otolith microchemistry studies: Directed downriver emigration to brackish‐water overwintering habitats was followed by upriver migration to spring–summer freshwater feeding and spawning habitats. Eight of 12 fish showed directed spring migrations upriver to their original tagging site and were repeatedly located there, indicating strong homing behavior and residence. These very specific patterns of homing indicate that local‐scale effects (e.g., fishing, pollution) can have persistent effects on components of the Hudson River striped bass population.

SEASONAL AND INTERANNUAL VARIATION IN THE ALLOMETRY OF ENERGY ALLOCATION IN JUVENILE STRIPED BASS

Survival rates during the first winter of life are strongly size dependent and variable in many temperate fish populations. Starvation is often implicated as the cause of size-dependent first-winter mortality, and interannual variation in energy accumulation and the allocation between growth and storage is a likely source of variability. We examined these processes in young-of-the-year Hudson River striped bass Morone saxatilis, which are known to experience size-selective winter mortality and a winter energy deficit. Neutral- lipid and lean-tissue masses were determined for fish of five consecutive year classes collected through the first year of life. Differences in scaling relationships between body length and neutral-lipid and lean-tissue mass were used to infer patterns of resource al- location. Lipid reserves scaled isometrically with body length in summer but increased at a greater rate than did body length in autumn and winter. Lean-tissue allometries were less variable but followed a similar seasonal cycle. Allometric slopes were homogeneous across years, but significant interannual variation in length-specific lipid content and lean-tissue mass in the later half of the growing season indicated variable allocation patterns. During winter, up to 21% of total energy content and 50% of neutral-lipid stores were depleted. The results indicate that energy allocation patterns result from interactions among season, ontogenetic stage, and body size. The variation in growth, allocation, and severity of the winter energy deficit likely interact to determine first-winter survival.

Identification of riverine, estuarine, and coastal contingents of Hudson River striped bass based upon otolith elemental fingerprints

Elemental fingerprints of otoliths from Hudson River striped bass Morone saxatilis were used to define resident, estuarine, and ocean migratory contingents, which had previously been de- termined by otolith microprobe analysis of Sr:Ca. Using solution-based inductively coupled plasma mass-spectrometry, 7 metals were quantified in whole otoliths. Discriminant analysis of elements showed a high degree of separation among the 3 migratory contingents. Barium was significantly higher in otoliths from the freshwater resident group, while Sr and Na were significantly lower in comparison to mesohaline and ocean contingents. Identification of contingents by the bulk chemistry method indicated that divergent migratory patterns persist over lifetimes for Hudson River striped bass.

Seasonal Energy Dynamics of Young-of-the-Year Hudson River Striped Bass

Mortality of young-of-the-year (age-0) temperate fish during the winter has often been attributed to depletion of energy reserves, which results in starvation. We examined the seasonal energy cycle in age-0 Hudson River striped bass Morone saxatilis with field collections and laboratory experiments to determine if winter mortality could be attributed to starvation. Compositional analyses of wild fish showed that age-0 striped bass stored energy in the form of lipids prior to winter and then experienced an energy deficit, losing 7 and 16% of total body energy, respectively, in the two winters examined. Compositional analyses were performed on fish from a laboratory experiment in which age-0 striped bass were exposed to ambient winter conditions. Mortality was associated with low energy levels in unfed treatments but not when food was provided daily. In neither treatment did starvation appear to be the ultimate cause of death, as wild fish were captured with energy levels lower than those observed among mortalities in either experimental treatment. Our results suggest that starvation is not the only cause of winter mortality that produces the observed size-dependent patterns among age-0 striped bass. Other stresses associated with overwintering likely interact with the energy deficit to determine the size-dependent patterns of winter mortality that are observed in temperate fishes.

Mitochondrial DNA Diversity of Roanoke River Striped Bass

Abstract The genetic heterogeneity of mitochondrial DNA (mtDNA) in Roanoke River striped bass Morone saxatilis was examined by restriction endonuclease analysis of mtDNA isolated from 32 specimens captured during the 1989 and 1990 spawning runs. Restriction fragment banding patterns based on restriction site polymorphisms revealed six distinct genotypes, designated I–VI, among the 32 sampled individuals. The predominant genotype, designated genotype I, was found in 59% of the individuals sampled, while genotypes defined by Acc I–Nde I (genotype II), Taq I (genotype III), Taq I–Hinf I (genotype IV), Dde I (genotype V), and Spe I (genotype VI) were found in 25%, 7%, 3%, 3%, and 3% of the individuals. Five distinct mtDNA fragment length variants, designated classes A–E, were identified from the same 32 individuals. The number and size of individual length variants agreed with those identified previously in striped bass populations from geographically distant sites. Analysis of the distribution of length vari...

Notes: A Morphological Explanation for Size-Dependent Anchor Tag Loss from Striped Bass

The potential consequences of the relationship between the design of the anchor (Dennison) tag and the morphology of its attachment site has never been considered. During 1976 and 1977, anchor tags (Floy FD-67C) were inserted in Hudson River striped bass Morone saxatilis in a location that should have resulted in the anchor of the tag lodging between the distal tips of the 18th and 19th neural spines. Although the distance between neural spines increases with fish length, tag anchors of the same length (10 mm) were used on all fish in 1976 and 1977. We later measured the gap between the 18th and 19th neural spines on 13 striped bass that were 102–655 mm total length and found, through linear regression, that a gap of 10 mm or more should occur in fish 592 mm or longer. Based on recaptures by anglers during 1976 and 1977, the number of days at large and the proportion of fish recaptured 50–365 d after tagging was significantly lower for fish that were 592 mm or longer than for fish shorter than 592 mm. The absence of such a relationship between Hudson River striped bass during 1986, when internal anchor tags were inserted into the abdomen of fish, indicates that anchor length and the distance between the bony structures used for attachment must be appropriately sized to reduce the probability of anchor tag loss.

Range Dynamics of Hudson River Striped Bass along the Atlantic Coast

We analyzed the movements of Hudson River striped bass Morone saxatilis along the Atlantic coast from the results of a tagging program conducted in the Hudson River estuary between 1984 and 1988. Almost 30,000 striped bass were marked with internal anchor tags; most measured between 200 and 800 mm total length (TL). Interpretations of recoveries are conditional because the distribution and selectivity of fishing effort along the Atlantic coast are unknown. The proportion of total recaptures from outside the Hudson River increased significantly with fish length and by season from spring through autumn. The geographic range of recoveries extended from the Bay of Fundy, Nova Scotia, to Cape Hatteras, North Carolina – a coastal range of about 1,500 km. Most fish recaptured in spring had traveled north and east; recoveries from south of the New York Bight were uncommon until autumn. Many recaptures came from tributaries; far northern recaptures, in particular, tended to occur in rivers or near river mouths. Mean monthly distances between the Hudson River and recapture sites were highest from June through October and increased significantly with fish length. Comparisons with previous studies suggested that the effective coastal range of Hudson River striped bass has expanded since midcentury, especially that of 200–400-mm TL fish. Recapture of a Hudson River-tagged striped bass off Cape Hatteras supports previous winter trawling studies that suggested that large Hudson River striped bass join schools of mixed origin that winter off the mid-Atlantic coast.

Simulation of Striped Bass Egg and Larva Development Based on Temperature

Abstract Comparisons of simulated and observed egg and larva abundance patterns for Hudson River striped bass Morone saxatilis during 1975 and 1976 provided support for a previously stated hypothesis that a sudden drop in water temperature during late May 1976 was associated with almost complete disappearance of cohorts spawned before that date. The major period of mortality for the earlier-spawned cohorts may have occurred during or immediately following egg hatching rather than immediately following yolk absorption as had been previously postulated.