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Wild bluegill, Lepomis macrochirus Rafinesque, succumb to seasonal mortality in the early spring during cool water temperatures, shown previously to be related to bacteraemia caused by a psychrotrophic bacterium, Pseudomonas mandelii. In the study herein, intestinal coccidiosis in wild bluegill had seasonal prevalence causing heavy intestinal infections and sloughing of intestinal epithelium occurring in late winter/early spring. Infections were predominantly related to two different species, Goussia washuti n. sp., an epicellular coccidium, and a coccidium closely resembling Goussia desseri Molnár 1996, previously only described in percid fish in Europe. In 2019, co‐infections of bacteraemia and intestinal coccidiosis occurred in bluegills. Evaluating coccidium infection intensity by fresh parasite examination and histology, an association was observed in which fish with moderate‐to‐heavy intestinal coccidiosis were 8–12 times more likely to have bacteraemia compared to fish with no or light coccidiosis. The association of these co‐infections suggests that intestinal coccidiosis could contribute to seasonal bacterial epizootics of wild bluegill.

Waterfowl managers first recognized the problem of lead poisoning in ducks from the ingestion of spent lead shot (pellets) over 100 years ago. The phase-out of lead shot for waterfowl hunting began in the Atlantic Flyway in the 1970s. Lead shot was subsequently banned throughout the United States and Canada prior to 2000. We compared blood-lead levels in American black ducks Anas rubripes wintering in coastal New Jersey in 1978, prior to the lead ban, and in 2017, about 39 years after lead shot was first banned for use in Atlantic coastal marshes and 27 years after it was banned for waterfowl hunting in New Jersey. The prevalence of blood-lead > 0.2 ppm, a level commonly used to indicate lead exposure, declined nearly four-fold from 1978 (79%) to 2017 (20%). We found no significant differences in the prevalence of birds with blood-lead levels > 0.2 ppm between sexes in either year or between age classes in 2017. The prevalence of ducks with blood-lead levels > 1.0 ppm, considered clinically evident toxicity, declined from 19% in 1978 to 1% in 2017. Our study provides further evidence that the ban on the use of lead shot over 20 years ago throughout North America has resulted in lower blood-lead levels in waterfowl. Notwithstanding, we still found evidence of lead exposure in black ducks in 2017, which warrants further investigation.

Lernaeenicus radiatus is a pennellid copepod with a 2-host life cycle that exhibits high host-specificity to their first host, black sea bass Centropristis striata. This parasite was prevalent in the gills of black sea bass juveniles and adults along the coast of New Jersey, USA, April to December 2019. Parasite incidence was high in the summer and fall in near-shore areas and dropped significantly in fish from deep waters further off-shore in December. Heavy infections of L. radiatus occurred in gills of adult black sea bass inhabiting reef-associated structures, in which parasite incidence rate was 2-3.7 times higher than in non-structure habitat. Less host-specificity occurred in second hosts which support female metamorphosis. In total, 7 fish species were confirmed as second hosts, with the most common being Atlantic menhaden Brevoortia tyrannus and bay anchovy Anchoa mitchilli. Incidence of L. radiatus depends on host abundance and habitats that support interactions of the preferred fish hosts, which may explain the heavy infections in reef habitats. The L. radiatus anchor process in metamorphosed females was highly polymorphic, depending on tissue tropism. Parasite length varied considerably, with neck and trunk measurements of L. radiatus from adult menhaden being 2-4 times larger than those from smaller host species. Mitochondrial cytochrome oxidase c subunit I (COI) sequences demonstrated all parasites to be L. radiatus, with sequence divergence limited to 0.3%. These findings show that morphology of the metamorphosed females has poor taxonomic value, and polymorphisms instead are related to attachment site and host characteristics.

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