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1.
Several species of bacteria have been isolated from diseased striped bass, Morone saxatilis (Walbaum), in Chesapeake Bay. Mycobacteria species are of particular interest because of their association with chronic lesions in both fish and humans. The resulting disease in fish may be characterised by emaciation, inflammation of the skin, exophthalmia (pop‐eye), ascites (dropsy), open lesions, and ulceration. The prevalence of mycobacterial infection in 217 striped bass in the Maryland portion of Chesapeake Bay was determined to provide evidence of decreased overall condition of fish affected by these bacteria. The density of the granulomas was higher in the spleen and head kidney than either the heart or liver, and appeared to be most closely associated with the presence of an external lesion. Thirty‐eight per cent of the fish showed some sign of an external lesion. Granulomas appeared in at least one organ in 53% of the fish sampled regardless of the presence or absence of an external skin lesion. Condition factor was significantly higher for striped bass without external lesions (0.96) than those with lesions (0.82). Striped bass with no internal granulomas and no external lesion had the highest condition factor (0.99) and fish with granulomas and external lesions the lowest (0.81). Slopes of the regression loge weight (g) and loge length (mm) for striped bass with external lesions was significantly higher than those fish without external lesions and had a lower r2. The results suggest that striped bass that are infected with mycobacteria have decreased overall health.  相似文献   

2.
Stable carbon isotope ratios were measured in archived striped bass, Morone saxatilis (Walbaum), scales to identify changes in the feeding behaviour of this species over time. Striped bass tissue and scale samples were collected from Rhode Island coastal waters during 1996 and archived scale samples (1982–1997) were obtained from Chesapeake Bay. Known striped bass prey items were also collected from Chesapeake Bay and analysed for δ13C. A significant correlation was observed between carbon isotope ratios in striped bass scales and muscle tissue (r2 = 0.52; P < 0.05). Carbon isotope ratios were enriched (less negative) in scales relative to muscle tissue by about 3‰. Carbon isotope ratios in archived striped bass scales from Chesapeake Bay increased significantly from ?16.7 ± 0.2‰ in 1982 to ?15.1 ± 0.3‰ in 1997. Benthic species, especially invertebrates, were isotopically enriched relative to pelagic fish species collected from the main‐stem of Chesapeake Bay. Prey samples collected from riverine locations within Chesapeake Bay were isotopically depleted relative to those collected in the open portion of the Bay. The changes in the carbon isotope ratios of the striped bass scales could be related to changes in the relative proportions of pelagic and benthic food items in the diet of striped bass or to changes in the feeding locations of this species. In either case, there have been changes in the feeding behaviour and/or relationships of the striped bass between 1982 and 1997. Such changes may be related to changing ecological conditions within the estuary, which could influence the health of Chesapeake Bay striped bass.  相似文献   

3.
The diet of Chesapeake Bay striped bass in the late 1950s   总被引：1，自引：0，他引：1  
The diet of Chesapeake Bay striped bass, (Morone saxatilis) Walbaum, based on unpublished stomach content data from 916 fish collected between 1955 and 1959 was described. The diet in the late 1950s, quantified using an index of relative importance (IRI), was dominated by Atlantic menhaden, Brevoortia tyrannus Latrobe. Atlantic menhaden (66%) and bay anchovy, Anchoa mitchilli Valenciennes, (19%) had the highest IRI value overall. Small striped bass (<600 mm total length) ate predominantly bay anchovy (IRI = 67%). Large striped bass (≥ 600 mm total length) ate predominantly Atlantic menhaden (IRI = 93%). Since 1990 small striped bass rely more on invertebrate prey and larger fish now rely more on small pelagic prey, such as bay anchovy and 0‐age clupeids. Analysis of historical data using current techniques provided a valuable tool for comparison to help in understanding the current striped bass predator–prey relationship in Chesapeake Bay.  相似文献   

4.
Between 1997 and 2000, an outbreak of skin lesions and observations of emaciated striped bass, Morone saxatilis (Walbaum), in upper Chesapeake Bay were attributed to a perceived shortage of its main prey, Atlantic menhaden, Brevoortia tyrannus Latrobe. Abundance estimates, Atlantic menhaden consumption per recruit analysis (modified yield‐per‐recruit), bioenergetics analysis and predator–prey theory were combined to explore whether an imbalance between striped bass and Atlantic menhaden in upper Chesapeake Bay was plausible. Reduced fishing mortality and higher size limits that underpinned the effort to restore striped bass during the 1980s and 1990s lead to more abundant and larger striped bass in upper Chesapeake Bay, increasing predatory demand for forage‐sized Atlantic menhaden, the abundance of which declined to a historic low. Nominal losses of age 0–2 Atlantic menhaden to harvest and potential striped bass predation exceeded supply after 1998. The outbreak of lesions in upper Chesapeake Bay striped bass coincided with increased variation in weight‐at‐length, decreased length‐at‐age, and decreased presence of Atlantic menhaden in diets. Decreased attack success, inferred from a 97% decline in ratios of forage‐sized Atlantic menhaden to striped bass between 1983 and 1998, would have expected to have been followed by a deterioration of striped bass nutritional state. Transmission of disease would have been aided by high density of striped bass in poor nutritional condition residing in degraded habitat (Chesapeake Bay was the most hypoxic estuary in the mid‐Atlantic region in the late 1990s). These problems suggest that striped bass exceeded their carrying capacity in Chesapeake Bay during the late 1990s.  相似文献   

5.
The recent increase in the Atlantic coast population of striped bass, Morone saxatilis (Walbaum), prompted managers to re‐evaluate their predatory impact. Published and unpublished diet data for striped bass on the Atlantic Coast of North America were examined for geographical, ontogenetic and seasonal patterns in the diet and to assess diet for this species. Diets of young‐of‐the‐year (YOY) striped bass were similar across the Upper Atlantic (UPATL), Chesapeake and Delaware Bays (CBDEL) and North Carolina (NCARO) areas of the Atlantic coast where either fish or mysid shrimp dominate the diet. For age one and older striped bass, cluster analysis partitioned diets based on predominance of either Atlantic menhaden, Brevoortia tyrannus (Latrobe), characteristic of striped bass from the CBDEL and NCARO regions, or non‐menhaden fishes or invertebrates, characteristic of fish from the UPATL, in the diet. The predominance of invertebrates in the diets of striped bass in the UPATL region can be attributed to the absence of several important species groups in Northern waters, particularly sciaenid fishes, and to the sporadic occurrences of Atlantic menhaden to UPATL waters. In all regions, across most seasons and in most size classes of striped bass, the clupeiod fishes; menhaden, anchovies (Anchoa spp.) and river herrings (Alosa spp,) and Atlantic herring, Clupea harengus L., dominated the diets of striped bass above the first year of life.  相似文献   

6.
Mycobacteriosis is a serious and often lethal disease of fish, affecting a wide range of species globally both in culture and wild settings. Caused by several species of the genus Mycobacterium , the disease has received considerable attention in recent years because of the discovery of new species in piscine hosts, epizootics in wild fisheries, and the ability of a few species to infect humans. The impact of this disease in aquaculture and the aquaria trade has been well reported and there is currently no widely accepted cure other than depopulation and facility disinfection. However, the impact on wild fisheries is poorly understood and may relate to species-specific interactions (host–pathogen) and possibly environmental stressors. In this review, much of what is known about mycobacteriosis in marine fish is summarized with particular attention to an epizootic in striped bass, Morone saxatilis , (Walbaum), in Chesapeake Bay, USA.  相似文献   

7.
Viral haemorrhagic septicaemia virus (VHSV) was isolated from mortalities occurring in populations of mummichog, Fundulus heteroclitus, stickleback, Gasterosteus aculeatus aculeatus, brown trout, Salmo trutta, and striped bass, Morone saxatilis, in New Brunswick and Nova Scotia, Canada. The isolated viral strains produced a cytopathic effect on the epithelioma papillosum cyprini cell line. Serum neutralization indicated the virus was VHSV and sequencing identified the rhabdovirus isolates as the North American strain of VHSV. Phylogenetic analysis indicated that the isolates are closely related and form a distinguishable subgroup of North American type VHSV. To our knowledge, this is the first report of VHSV in mummichog and striped bass.  相似文献   

8.
The emergence of a new sublineage of viral hemorrhagic septicemia virus (VHSV) within the Laurentian Great Lakes has caused concern for aquaculture in the United States. Because of the occurrence of VHSV in a new geographic location, new host species have been identified and the complete host range has not been determined. This study confirmed the high resistance of rainbow trout, Oncorhynchus mykiss, to VHSV type IVb infection. In addition, the experimental susceptibility of hybrid striped bass, Morone chrysops ♂ × Morone saxatilis ♀, to VHSV type IVb infection was examined but determined to be highly dependent on age of fish and exposure temperature. No mortality was observed in adult fish infected via intraperitoneal (IP) injection at 15 C, whereas yearling fish infected via IP injection under the same conditions experienced 20.8% mortality. Among yearling fish infected via IP injection, mortality increased to 100% when exposure to VHSV occurred at 10 C. An LD50 for yearling hybrid striped bass exposed to VHSV at 10 C by IP injection was determined to be 1.4 × 104 pfu (SE = 2.1). Thus, at 10 C, yearling hybrid striped bass experience a high mortality when exposed to VHSV IVb by IP injection.  相似文献   

9.
Advances in molecular analyses have permitted documentation of an increasing spectrum of mycobacteria infecting fish. Although some of these mycobacteria are not closely related, several species belong to the Mycobacterium tuberculosis clade. One member of the clade, M. marinum, is well known as an agent of piscine mycobacteriosis. Three other clade species, M. shottsii, M. pseudoshottsii and M. 'chesapeaki', have recently been identified as predominant disease agents in a widespread, continuing epizootic in wild striped bass of the Chesapeake Bay. A fifth clade member, M. ulcerans, has recently been indirectly detected in wild, African cichlid fish. As M. ulcerans is the third most common human mycobacterial infection worldwide, even such indirect evidence of M. ulcerans in fish must be more thoroughly investigated. Complicating the differentiation of these clade members is the growing recognition of intraspecies and interspecies variation in phenotypes, genes and virulence. Thus, researchers must be aware of the variety of piscine isolates within the M. tuberculosis clade. This review summarizes the methods of detection and differentiation for this important group of mycobacteria.  相似文献   

10.
The small‐scale distribution and retention mechanisms of white perch (Morone americana) and striped bass (M. saxatilis) early‐life stages were investigated in the upper Chesapeake Bay estuarine turbidity maximum (ETM). Physical measurements and biological collections were made at fixed‐location stations within the ETM during three research cruises in 1998 and two in 1999. Results were compared with mapping surveys of physical properties and organism distributions above, within, and below the ETM. Physical conditions at the fixed stations differed markedly among cruises and between years due to differences in freshwater flow and wind. In each year, striped bass and white perch larval concentrations were highest in waters of salinity 1–4. Larvae were more abundant in the ETM region in 1998, a high‐flow year, suggesting that the ETM provides favorable nursery habitat when low salinity waters and the ETM coincide in high freshwater‐flow conditions. In 1998, the earliest pelagic life stages of fish larvae (eggs, yolk‐sac larvae) and the copepod Eurytemora affinis, an important prey of feeding larvae, apparently were retained in deep, landward‐flowing water within the salt front and ETM region. Statistical analyses indicated that distributions of white perch and striped bass post‐yolk‐sac larvae were associated with E. affinis distributions and suggested that retention of larval fish could result from tracking prey. Comparing fixed‐station and mapping approaches demonstrates the importance of sampling at different spatial scales within the ETM region and suggests that larvae are faced with trade‐offs between selecting zones of high retention or high visual‐feeding success.  相似文献   

11.
Delaware River and Bay Morone saxatilis (Walbaum), striped bass, have recently undergone a dramatic recovery. Here, we examine spatio‐temporal patterns in the distribution and food habits of striped bass in marsh creeks in the estuary (salinity range 1–20 psu), 1996–2000. Sampling occurred monthly, April through November, with otter trawls (4.9 m, 6 mm mesh, n = 6760) and weirs (intertidal block nets, 6 mm mesh, n = 647) at eight sites. Young‐of‐the‐year (YOY) fish were generally more than 10 times more abundant at oligohaline sites, although they were abundant at mesohaline sites in 1996, the lowest salinity year. Small striped bass (<100 mm) in creeks relied on mysids and other crustaceans and became more piscivorous with size. Overall, they consumed 46% by weight fish, of which 52% were mummichog, Fundulus heteroclitus (L.), and 18% were YOY Atlantic croaker, Micropogonias undulatus (L.), prey types which are not typical in most food habits studies and are indicative of feeding in marsh creeks. These data suggest that young striped bass are an abundant component of Delaware Bay marsh creek fauna and may play an important role in trophic relays within this system.  相似文献   

12.
Fish-derived antimicrobial peptides are an important part of the innate immune system due to their potent antimicrobial properties. Piscidins are a class of antimicrobial peptides first described in hybrid striped bass (Morone chrysops x Morone saxatilis) but have also been identified in many other fish species. Previous work demonstrated the broad antimicrobial activity of piscidins against Gram-negative and Gram-positive bacterial species. This study sought to determine the extent to which class I (striped bass piscidin 1, white bass piscidin 1 and striped bass/white bass piscidin 3) and class II (striped bass piscidin 4 and white bass piscidin 5) piscidins inhibit biofilm formation of different Gram-negative bacteria. In general, the class I and II piscidins demonstrate potent activity against Escherichia coli and Flavobacterium columnare biofilms. The class II piscidins showed more activity against E. coli and F. columnare isolates than did the class I piscidins. The piscidins in general were much less effective against inhibiting Aeromonas hydrophila and A. veronii biofilm growth. Only the class I piscidins showed significant growth inhibition among the Aeromonas spp. examined.  相似文献   

13.
The productivity and profitability of striped and hybrid bass Morone sp. aquaculture would be enhanced by genetic improvement of cultured stocks. To date, genetic improvement of cultured bass stocks largely has been limited to interspecific hybridization and ploidy manipulation, techniques which are aimed at short-term genetic gains. Upon domestication, long-term improvement of striped or hybrid bass can be approached. Lines of striped bass and other Morone species can be selected for rapid growth, stress tolerance, disease resistance, combining ability, or other traits. Improved lines can be crossed to produce superior hybrids or crossbreds, or manipulated to produce superior triploid or transgenic stocks. Current breeding projects are limited in size, and coordination of breeding activities among groups would be advantageous. Faced with the likelihood of limited government funding, long-term genetic improvement of Morone species might be supported by the industry through a fund receiving a small percentage of the proceeds from sales of cultured Morone products.  相似文献   

14.
Trophic dynamics and conceptual niche spaces of top piscivores were assessed using stable isotope analysis following the introduction of hybrid striped bass Morone saxatilis (Walbaum) × Morone chrysops (Rafinesque) into an established reservoir fishery devoid of gizzard shad, Dorosoma cepedianum (Lasueur). Hybrid striped bass were initially stocked into Three Mile Lake, Iowa as an attempt to biologically control pervasive yellow bass, Morone mississippiensis Jordan & Eigenmann, populations. From the analyses, it concluded that hybrid striped bass predominately targeted prey fish located in the littoral habitats of the reservoir and did not selectively consume yellow bass as intended. Bayesian isotope mixing models described the diets of hybrid striped bass to include a variety of prey fish, predominantly consisting of young bluegill Lepomis macrochirus and yellow bass. Food resource overlap among hybrid striped bass, largemouth bass, Micropterus salmoides Lacépède, and walleye, Sander vitreus (Mitchill), appeared substantial based on the isotopic niche overlap model. Results from this case study, in conjunction with the hindsight that yellow bass populations became prolific even with stockings of hybrid striped bass, suggest that their use to control yellow bass populations may not be a viable management strategy in southern Iowa.  相似文献   

15.
The striped bass, Morone saxatilis (Walbaum), once represented an important resource for fisheries in the St Lawrence River (Quebec, Canada). A restoration programme, involving captive propagation, was implemented with the objective of restocking the population, which had disappeared in the late 1960s. An unusually high rate of mortality was observed during the winter of 2006 in captive-raised fingerlings that were originally collected from the Miramichi River (New Brunswick, Canada) the previous summer. Post-mortem examinations revealed extensive granulomatous and hyperplastic peritonitis associated with numerous nematodes of the genus Philometra. Given the severity of the lesions, high intensity of infection by Philometra sp. was presumed to be the primary factor in the unusual mortalities reported that winter. Observations suggest that this nematode, which was acquired in the wild, cannot establish itself in a captive environment, most likely because of the absence of the obligate intermediate host. Examination of archived specimens of striped bass showed that this parasite was probably present in the St Lawrence River population prior to its extirpation. Consequently, the introduction of infected fish into this ecosystem should not be a concern. Nevertheless, infection-related mortalities of fingerlings might affect dynamics of wild striped bass populations.  相似文献   

16.
Catch‐and‐release fishing has increased in many fisheries, but its contribution to fishing mortality is rarely estimated. This study estimated catch and release mortality rates of striped bass, Morone saxatilis (Walbaum), for the spring recreational fishery in the Hudson River. Treatment fish (caught with live bait on spinning gear) and control fish (captured by electric fishing) were placed in in situ holding pens for 5 days. Mortality rates were estimated using conditional instantaneous mortality rates and additive finite mortality rates. Influences of variables (playing and handling time, hook location, degree of bleeding and fish length) on hooking mortality rates were examined by logistic regression. Conditional instantaneous mortality rates and additive finite mortality rates were 31 and 28%, respectively. Hook location significantly affected the survival of striped bass. Angling catch, effort, and release rates must be integrated with associated hooking mortality rates before this component of overall population mortality can be incorporated into management decisions.  相似文献   

17.
The potential impact of increasing striped bass, Morone saxatilis (Walbaum), populations on prey biomass under two different spatial scales: a broad perspective involving Atlantic coast‐wide populations and a finer‐scale analysis within the Hudson River, was modelled. Coast‐wide striped bass consumption ranged from 17 900 t (1982) to 147 900 t (1995). This level of consumption is equivalent of up to 57% of US menhaden landings over this period. Assuming 10% of diets comprise alosids, Hudson River striped bass ate 26.4–140.7 t of alosids annually from 1985 to 1994 – exceeding the estimated age‐0 alosid biomass in the river in 1990 (15.3 t). Analysis of possible management actions to reduce predatory demand was conducted. However, to achieve a 30% reduction in predatory demand would require movement towards historical overfishing conditions. Thus, it may not be possible to manage for high striped bass population levels and high levels of other species upon which they feed due to the competing demands for those species as prey and commercial or recreational resources.  相似文献   

18.
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19.
Abstract. Four 0.05-ha research ponds were filled with brackish water (12 ppt) for the purpose of evaluating zooplankion dynamics and predator-prey interactions. Three of the ponds were stocked with Chesapeake striped bass, Morone saxatilis (Walbaum). All ponds were fertilized to stimulate zooplankton blooms using a protocol that has been successful in freshwater systems. Zooplankton was dominated by four major groups: rotifers, copepod nauplii, Eurytemora adults and Eurytemora copepedites with rotifers and the nauplii being the most abundant organisms found. Rotifer populations peaked 15-20 days after filling while the copepods peaked 17-22 days after filling. Fish production was very similar to that found in freshwater ponds with an average yield of 84.4 kg/ha (2.0 kg/ha/day) for phase 1 fish (=45mm). Food selectivity indices indicated striped bass avoided both rotifers and copepod nauplii and preferred adult and copepedite Eurytemora as a food item. However, due to various problems associated with sampling, these selectivity results should be considered with caution. The findings of this study reveal fertilization regimes used successfully in freshwater production systems can be applied in an estuarine environment.  相似文献   

20.
Abstract.— Meiotic gynogens were produced using hybrid striped bass (♀ white bass, Morone chrysops , ×♂ striped bass, M. saxatilis ) eggs and white perch M. americana UV-irradiated sperm. Diploidy of the fertilized eggs was restored by application of hydrostatic pressure, which induced retention of the second polar body. Use of white perch sperm provided an unmistakable marker for detection of a paternal genetic contribution. Two assays were developed using the polymerase chain reaction (PCR) to amplify specific regions of the Morone genome . Primers for gene amplification were developed based on the DNA sequence of the striped bass growth hormone gene (SB-GH) or an anonymous striped bass locus (SBI-10). Control experiments using DNA from the three Morone species demonstrated that gene amplification yielded species-specific patterns of DNA fragments for both of these loci. Therefore, any progeny with a paternal contribution of a set of white perch chromosomes could be identified. Using these assays, we demonstrated that greater than 75% of the progeny obtained from successful experiments were true gynogens. These striped bass hybrid gynogens will provide the basis for future efforts to calculate gene-centromere distances and to identify markers linked to specific traits of interest to aquaculture.  相似文献   

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