Health status evaluation of striped bass ( Morone saxatilis ) exposed to low temperature in sea cage culture during the grow‐out

We examined the role of salinity, body size, and energetic state in determining low temperature tolerance of young-of-the-year (YOY) striped bass (Morone saxatilis) and used this information to map optimal overwintering habitat in the Hudson River estuary. A long-term experiment compared survival at 15 ppt and 30 ppt. In additional experiments, winter-acclimated fish were exposed to temperature declines (2.3°C·day1 to 1°C·week1) at salinities from 0 ppt to 35 ppt. Highest survival at low temperatures was consistently observed at intermediate salinities. These results suggest that the observed distribution of overwintering striped bass is related to physiological constraints on osmo regulatory ability at low temperatures. Low temperature tolerance appeared unrelated to body size and energetic state. Salinity profiles were used to describe the location and extent of optimal wintering habitats under various hydrographic regimes. The location of optimal habitats was displaced by over 27 km along the river axis because of variation in salinity regime. Changes in the availability of optimal habitat may be responsible for variation in recruitment to the Hudson River population. These results demonstrate the need to consider a holistic approach encompassing all seasons of the year in assessing habitat requirements of fishes.

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Emamectin benzoate is a safe and effective anthelmintic against coelomic nematode Philometra rubra in striped bass Morone saxatilis

Diseases of Aquatic Organisms ◽

10.3354/dao03530 ◽

2020 ◽

Vol 142 ◽

pp. 47-53

Author(s):

K Béland ◽

G Séguin ◽

S Lair

Keyword(s):

Mortality Rate ◽

Striped Bass ◽

High Mortality ◽

Morone Saxatilis ◽

Treatment Results ◽

Emamectin Benzoate ◽

Once Daily ◽

Fish Hatchery ◽

Parasitic Burden

An unusually high mortality rate due to verminous (Philometra rubra) coelomitis was documented in wild-hatched striped bass Morone saxatilis raised in a fish hatchery as part of a stock restoration program. To decrease the parasitic burden and therefore potentially minimize mortality, the effectiveness of 2 different anthelmintics was evaluated. Two trials were conducted on wild-collected fingerlings naturally infected by P. rubra. In 2006, 144 yearling fish were randomly assigned to 4 experimental groups: (1) levamisole (Levasol®) at 2 mg l-1 via immersion for 8 h once weekly for 3 wk; (2) levamisole at a dose of 2.5 mg kg-1 biomass via feed once daily for 7 d; (3) emamectin benzoate (Slice®) at a dose of 0.05 mg kg-1 biomass via feed once daily for 7 d; and (4) control. Emamectin successfully eliminated live nematodes in 84.9% of the fish, whereas the administration of levamisole, either via immersion or feed, was not successful in significantly reducing the number of live P. rubra. In 2007, the administration of the same dosage of emamectin to approximately 1000 naturally infected yearling striped bass was associated with a 100% mortality rate of P. rubra in the 30 fish randomly examined 5 wk after the beginning of the treatment. Results of these trials indicate that, at the dosage used, the administration of emamectin at the end of the summer is safe for striped bass yearlings and considerably reduces the prevalence and intensity of the infection by this parasite.

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Feeding ecology of early life stages of striped bass (Morone saxatilis) along an estuarine salinity-turbidity gradient, St. Lawrence Estuary, Canada

Journal of Plankton Research ◽

10.1093/plankt/fbz031 ◽

2019 ◽

Vol 41 (4) ◽

pp. 507-520 ◽

Cited By ~ 1

Author(s):

L Vanalderweireldt ◽

P Sirois ◽

M Mingelbier ◽

G Winkler

Keyword(s):

Striped Bass ◽

Feeding Ecology ◽

Early Life ◽

Morone Saxatilis ◽

Early Summer ◽

Gut Contents ◽

Life Stages ◽

Early Life Stages ◽

Lawrence Estuary ◽

Feeding Niche

Abstract After being extirpated from the St. Lawrence River in the 1960s, striped bass (Morone saxatilis) were reintroduced to the estuary in 2002 and by 2008, they were naturally reproducing. To document the habitat use and feeding ecology of this reintroduced population, we examined the gut contents of 333 larvae and juveniles. Samples were collected in four estuarine habitats in 2014: the upstream freshwater section (UP), the oligohaline (O-ETM) and the mesohaline (M-ETM) estuarine turbidity maximum zones, and the downstream polyhaline section (DOWN). In June, pelagic larvae developed in the UP and the O-ETM, feeding mainly on copepods such as Eurytemora affinis. The O-ETM exhibited better suitable feeding conditions compared to the UP, likely due to the presence of Bosmina sp. as a primary prey. After July, striped bass shifted to larger prey items, consuming mainly dipteran pupa in upstream littoral habitats and gammarids and mysids in downstream habitats. In the early summer, the UP provided a high-quality nursery habitat and as the season progressed, the smallest juveniles dispersed downstream and improved their feeding success by exploiting a new feeding niche. This observation suggests that being distributed throughout the estuary may increase the potential survival of striped bass early life stages.

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