Lethal and Sublethal Toxicity of Drilling Fluids to Larvae of the American Lobster, Homarus americanus

1984 ◽  
Vol 41 (9) ◽  
pp. 1334-1340 ◽  
Author(s):  
Jennifer G. Smith Derby ◽  
Judith M. Capuzzo

The lethal and sublethal effects of five used, whole drilling fluids on the larval stages of the American lobster (Homarus americanus) were assessed in laboratory experiments using a continuous-flow bioassay. Although the five tested drilling fluids varied markedly in their toxicity, some were highly toxic, with LC50 values as low as 74 mg/L. Sublethal exposures to drilling fluids at concentrations as low as 10–50 mg/L resulted in reduced respiration rates, reduced O:N ratios, and increased protein:lipid ratios, demonstrating a change in energetics of the larval lobsters. Growth and development of the larvae were seriously impaired by exposure to three of the five drilling fluids at concentrations of 50 and 100 mg/L. The feeding rates were also significantly reduced after a 24-h exposure to 50 mg/L drilling fluid. Exposure of larvae to barite (a major component of drilling fluids) and to a field-collected, fine-grained sediment did not result in deleterious effects. We suggest that the chemical components and not the physical properties of the drilling fluids are primarily responsible for detrimental effects. From results of the chemical analyses of the tested drilling fluids, we consider that the adverse effects of these drilling fluids cannot be attributed to any one group of chemicals. For example, diesel oil, a known toxicant, was present in the more toxic drilling fluids; however, there was no direct correlation between the toxicity of a drilling fluid and diesel oil concentration. Phenolic compounds, various metals, and other components probably also contributed to the toxicity of these drilling fluids.


Aquaculture ◽  
1974 ◽  
Vol 3 (3) ◽  
pp. 311-314 ◽  
Author(s):  
Steven A. Serfling ◽  
Jon C. Van Olst ◽  
Richard F. Ford


2019 ◽  
Vol 39 (4) ◽  
pp. 468-476 ◽  
Author(s):  
Amalia M Harrington ◽  
Heather J Hamlin

ABSTRACT Increased anthropogenic input of carbon dioxide into the atmosphere has caused widespread patterns of ocean acidification (OA) and increased the frequency of extreme warming events. We explored the sublethal effects of OA on the hemolymph chemistry and physiological response to acute thermal stress in the American lobster (Homarus americanus H. Milne Edwards, 1837). We exposed subadult lobsters to current or predicted end-century pH conditions (8.0 and 7.6, respectively) for 60 days. Following exposure, we assessed hemolymph L-lactate and calcium concentrations (as indicators of oxygen carrying capacity), ecdysterone concentrations, total protein content, and total hemocyte counts (THCs) as an indicator of immune response. We also assessed cardiac performance in the context of an acute warming event using impedance pneumography. Calcium, total protein, and ecdysterone concentrations were not significantly altered (P ≥ 0.10) by OA exposure. Control lobsters, however, had significantly higher levels of L-lactate concentrations compared to acidified lobsters, suggesting reduced oxygen carrying capacity under OA. THCs were also 61% higher in control versus acidified lobsters, suggesting immunosuppression under chronic OA. Lobsters exposed to acidified conditions exhibited reduced cardiac performance under acute warming as indicated by significantly lower (P = 0.040) Arrhenius Break Temperatures compared to control lobsters. These results suggest that although some physiological endpoints of American lobster are not impacted by OA, the stress of OA will likely be compounded by acute heat shock and may present additional physiological challenges for this species in the face of future change.



Drilling operations from platforms in the North Sea result in the production of large quantities of drill cuttings. These are a variable mixture of rock chippings, clays and original drilling fluids. Drilling mud is cleaned on the platform to remove rock chips before re-use of the mud. The rejected fraction from the clean-up plant (the cuttings) contains some of the base drilling fluid, and this can lead to an organically rich input to the sea-bed. Cuttings are discarded immediately underneath the platform jacket and thus build-up over the natural seabed sediment. In many cases this cuttings pile may cover considerable areas of seabed, leading to seabed biological effects and potential corrosion problems. Different types of cuttings have different environmental impacts, this being partly dependent upon their hydrocarbon component. Diesel-oil based cuttings contain significant amounts of toxic aromatic hydrocarbons, whereas low-toxicity, kerosenebased cuttings contain less. Both types of cuttings support an active microbiological flora, initiated by hydrocarbon oxidation. This paper presents a study of microbiological degradation of hydrocarbons in cuttings piles around two North Sea platforms. Results indicate that there is a close correlation between microbiological activity and hydrocarbon breakdown in the surface of cuttings piles and that both of these parameters reach their maximum values closer to the platform when low-toxicity muds are in use.



1977 ◽  
Vol 1977 (1) ◽  
pp. 569-573
Author(s):  
Joseph M. Forns

ABSTRACT The effects of API reference South Louisiana crude oil upon four larval stages of American lobster (Homarus americanus) were determined in a flow-through system. Tests were conducted with naturally-hatched animals in individual test chambers as well as in mass culture systems in an operating state lobster hatchery. Experimental flow-through crude oil exposure concentrations were 0.1, and 1.0 ppm, administered as a strongly-agitated emulsion-like mix to ambient temperature seawater ranging from 15°-20°C. Oil exposure residence times ranged from 0.8-5.6 minutes depending on the test. Exposed animals were monitored six times daily for feeding behavioral characteristics, mobility, molting success, growth and development times to reach the fourth larval stage. Pigmentation analysis was performed on individual larvae by photomicroscopy, and hydrocarbon analyses were also conducted thereon. Post-larval development through the eighth stage was investigated. Statistical comparisons were made among different control animals and between control and oil-exposed larvae.



2016 ◽  
Vol 74 (4) ◽  
pp. 1210-1219 ◽  
Author(s):  
Jesica D. Waller ◽  
Richard A. Wahle ◽  
Halley McVeigh ◽  
David M. Fields

Few studies have evaluated the joint effects of elevated temperature and pCO2 on marine organisms. In this study we investigated the interactive effects of Intergovernmental Panel on Climate Change predicted temperature and pCO2 for the end of the 21st century on key aspects of larval development of the American lobster, Homarus americanus, an otherwise well-studied, iconic, and commercially prominent species in the northeastern United States and Atlantic Canada. Our experiments showed that larvae (stages I–III) and postlarvae (stage IV) reared in the high temperature treatments (19 °C) experienced significantly lower survival, developed twice as fast, and had significantly higher oxygen consumption rates, than those in ambient treatments (16 °C). Larvae from the ambient temperature/high pCO2 (750 ppm) treatment had significantly longer carapace lengths, greater dry masses in stages I–III and higher C: N ratios in stage IV than larvae from all other treatments. Stage IVs raised in the high pCO2 treatment at 19 °C had significantly higher feeding rates and swimming speeds than stage IVs from the other three treatments. Together these results suggest that projected end-century warming will have greater adverse effects than increased pCO2 on larval survival, and changing pCO2 may have a complex effect on larval metabolism and behaviour. Understanding how the most vulnerable life stages of the lobster life cycle respond to climate change is essential in connecting the northward geographic shifts projected by habitat quality models, and the underlying physiological and genetic mechanisms that drive their ecology.



1986 ◽  
Vol 43 (11) ◽  
pp. 2177-2183 ◽  
Author(s):  
G. P. Ennis

The swimming capacity of American lobster, Homarus americanus, larvae in flowing water was observed in a screened-off portion of a flow tank. At a flow rate of 2 cm∙s−1, stage I–III larvae were swimming for 46–74% of the observations during the first 5 min but this ranged from 0 to 28% toward the end of a 30-min period. At higher flow rates, however, very few of these larvae were able to continue swimming longer than 5 min. Newly molted stage IV larvae displayed substantially improved swimming ability compared with earlier stages. At 2 cm∙s−1, these larvae were swimming for 40–48% of the observations over the 30-min period, although at higher flow rates their capacity to continue swimming was also limited and few were observed swimming longer than 10 min. Older stage IV larvae were more capable swimmers than newly molted stage IV larvae and displayed a capacity to continue swimming over the 30-min observation period at flow rates up to 9 cm∙s−1. In flowing water, the frequency of orientation in the upstream direction for larvae that were swimming was higher than for control larvae. For stage IV larvae especially, this frequency was higher at the higher flow rates. The observations demonstrate the presence of a rheotactic response in all larval stages of the American lobster. The response is relatively weak in stages I–III but strong in stage IV.



2016 ◽  
Author(s):  
Eric J Pedersen ◽  
Ryan R.E. Stanley ◽  
Paul V.R. Snelgrove ◽  
Frederic Guichard

Predicting dispersal paths of marine larvae with long pelagic durations, such as American lobster (Homarus americanus), requires understanding the cues to which larvae respond, and how that response reflects changes in larval behaviour. If larvae respond to conspecific presence by varying their movement, this behaviour can bias laboratory estimates of environmental responses. We tested whether larvae actively decreased their local intraspecific density by measuring how the vertical distribution of larvae changed under high versus low concentrations of conspecifics. We observed weak increases in vertical dispersion at higher concentrations in both newly-hatched larvae and in post-larvae, but not in intermediate larval stages. Further, we found that larvae from different mothers consistently differed in vertical distribution, which may indicate maternal effects on dispersal behavior. We also tested for differences in horizontal swimming behaviour in high and low concentrations, by fitting a novel random walk model that allowed us to model both larval interactions and persistent turning behaviours. We showed substantial reduction in diffusive behaviour under high concentration conditions resulting from more frequent turns by each larva, but no evidence for consistent avoidance of conspecifics. Our study is the first to demonstrate concentration-dependent behaviours in lobster larvae.



Aquaculture ◽  
2000 ◽  
Vol 182 (1-2) ◽  
pp. 37-47 ◽  
Author(s):  
L.E Burridge ◽  
K Haya ◽  
F.H Page ◽  
S.L Waddy ◽  
V Zitko ◽  
...  


2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Marie A. I. N. Rötzer ◽  
Joachim T. Haug

We redescribe the larval stages of the European lobster,Homarus gammarus, based on autofluorescence composite imaging. We focus on larval stages (II) to (IV). Compared to the American lobster,Homarus americanus, differences are most apparent in stage (III). This stage appears more mature inH. gammarus; for example, the rostrum is already curved and bears spines, and the appendages are better developed and longer and more differentiated. InH. americanusstage (III) shows a stronger resemblance to stage (II). As a result of the morphology of stage (III), the “metamorphic” moult between stage (III) and stage (IV) inH. gammarusis less drastic than inH. americanus. Metamorphosis is characterised by two criteria. It involves (1) a drastic change in morphology in (2) a short amount of time. It has hence been suggested that a more pronounced metamorphosis evolves by two factors affecting these criteria, namely, (1) the evolution of specialised larval features, which increase the morphological disparity between larva and adult that makes the change of morphology more drastic, and (2) the skipping of entire stages. This means larval forms ancestrally moult over several intermediate forms into the definite adult morphology. Yet, in more derived forms the stages with intermediate morphologies are no longer expressed; highly specialized larvae moult into the adult within a single moult (in the most extreme case) hence bridging the morphologies of larvae and adult in a shorter amount of time. The example of the twoHomarusspecies demonstrates that this explanation is not the only possible one. Additionally, differences of a single larval stage (in this case larval stage (III)) can lead to a more or less metamorphic-appearing ontogenetic sequence.



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