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 Published and unpublished diet data for striped bass on the Atlantic Coast of North America were examined for geographical, ontogenetic and seasonal patterns in the diet and to assess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.

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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.

We collected striped bass Morone saxatilis from 1998 to 2001 (n ¼ 2,703) and compared the seasonal feeding patterns of four size-groups (small [150-300 mm total length], medium [301-500 mm], large [501-700 mm], and extra large [.700 mm]) among three general regions (upper, middle, and lower) in Chesapeake Bay. Invertebrates dominated the diet of small striped bass during spring in all regions, and by fall bay anchovy Anchoa mitchilli became the dominant prey in the middle and lower regions. Pelagic schooling fishes were the primary prey for the larger size-groups. For medium striped bass, bay anchovy accounted for most of the prey eaten during spring and represented more than 50% of the diet by weight in summer in the upper and lower regions. Collectively, Atlantic menhaden Brevoortia tyrannus and bay anchovy accounted for more than 60% of the diet by weight in the lower region. Gizzard shad Dorosoma cepedianum and Atlantic menhaden were the dominant prey for medium and large fish from summer through winter in the upper region. Blue crab Callinectes sapidus accounted for 45% of the diet by weight for large striped bass during the summer in the middle and lower regions of the bay. For extra-large striped bass, menhaden, along with bay anchovy and spot Leiostomus xanthurus, were the primary prey eaten throughout the year in all regions. Bay anchovy have become more important for extra-large fish, representing between 16.0% and 29.0% of the diet by weight during the spring and summer. This increase represents a greater reliance by larger striped bass on small pelagic prey. It also suggests a greater ecological connection between bay anchovy and striped bass production.