scholarly journals Linking rising pCO2 and temperature to the larval development and physiology of the American lobster (Homarus americanus)

2016 ◽  
Vol 74 (4) ◽  
pp. 1210-1219 ◽  
Author(s):  
Jesica D. Waller ◽  
Richard A. Wahle ◽  
Halley McVeigh ◽  
David M. Fields
Keyword(s):  
Climate Change ◽  
Larval Development ◽  
Stage Iv ◽  
Homarus Americanus ◽  
Larval Survival ◽  
Interactive Effects ◽  
High Pco2 ◽  
American Lobster ◽  
Feeding Rates ◽  
Intergovernmental Panel

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.

Effect of Temperature on the Behavior of Stage IV American Lobster (Homarus americanus) Larvae

2015 ◽  
Vol 34 (2) ◽  
pp. 545-554 ◽  
Author(s):  
Melanie Chiasson ◽  
Gilles Miron ◽  
Dounia Daoud ◽  
Martin D. Mallet
Keyword(s):  
Stage Iv ◽  
Homarus Americanus ◽  
Effect Of Temperature ◽  
American Lobster

Effects of Crude Oil on American Lobster (Homarus americanus) Larvae in the Laboratory

1976 ◽  
Vol 33 (7) ◽  
pp. 1604-1614 ◽  
Author(s):  
Peter G. Wells ◽  
John B. Sprague
Keyword(s):  
Crude Oil ◽  
Larval Development ◽  
Food Consumption ◽  
Ultrasonic Vibration ◽  
Homarus Americanus ◽  
American Lobster ◽  
Fourth Stage ◽  
Dispersed Oil ◽  
Reference Toxicant

Four-day LC50s for Venezuelan Tia Juana crude oil were 0.86 mg/liter for first-stage larvae of the American lobster (Homarus americanus) and 4.9 mg/liter for third- and fourth-stage larvae. The 30-day LC50 was 0.14 mg/liter for larvae starting the test in their first stage. The threshold for retardation of larval development was about the same as the 30-day LC50. Decreased food consumption was demonstrated at 0.19 mg/liter. More "intermediate" larvae developed in oil exposures but no threshold was estimated. The ratio of "safe" to acutely lethal concentrations was about 0.03.Oil concentrations decreased during exposures; stated values could be multiplied by 0.59 to arrive at conventional average exposures. Stirring and ultrasonic vibration for 30 min dispersed averages of 7.4 and 18% of added oil. This and other techniques apparently dispersed similar components since toxicities were the same when based on measured concentrations. Aged dispersions were also equally toxic on a measured basis. Particles larger than 1.2 μm made up 84–96% of the dispersed oil and were about one-third as toxic as smaller particles and dissolved oil. For the reference toxicant DSS, the 4-day LC50 was 0.72 mg/liter for first-stage larvae indicating that lobster larvae are sensitive. Post-larval lobsters dug significantly more burrows when the substrate contained oil but did not avoid oiled substrate nor was growth or survival affected for substrates containing up to 1740 mg/liter of oil.

Swimming Ability of Larval American Lobsters, Homarus americanus, in Flowing Water

1986 ◽  
Vol 43 (11) ◽  
pp. 2177-2183 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Stage Iv ◽  
Homarus Americanus ◽  
American Lobster ◽  
Flowing Water ◽  
Swimming Ability ◽  
Flow Rates ◽  
Larval Stages ◽  
Upstream Direction ◽  
Swimming Capacity ◽  
Observation Period

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.

Aspects of the Biology of Pseudocarcinonemertes homari and Its Association with the American Lobster, Homarus americanus

1985 ◽  
Vol 42 (2) ◽  
pp. 351-356 ◽  
Author(s):  
D. E. Aiken ◽  
S. L. Waddy ◽  
L S. Uhazy
Keyword(s):  
Larval Development ◽  
Homarus Americanus ◽  
Egg Mass ◽  
American Lobster ◽  
Free Swimming ◽  
European Lobster ◽  
Newly Hatched Larvae

Pseudocarcinonemertes homari can reproduce on and destroy the egg mass of both the American (Homarus americanus) and the European lobster (H. gammarus) but does not appear to be a problem for brachyuran species. The eggs of P. homari are subspherical, average 251 × 260 μm, and are contained in individual compartments in a membranous brood sac that is attached to the lobster abdomen or egg mass. An average of 39 eggs occur in a brood sac. Newly hatched larvae are ciliated, lack anterior and posterior tufts, cirri or flagella, and are retained in the brood sac. Larval development is direct, and there is no free-swimming stage. After the larvae break out of the brood sac they join the adults and juveniles on the lobster egg mass. Many lobsters gradually remove infested eggs, but on those that do not, the nemertean population can increase to more than 14 000 individuals. After the lobster eggs are destroyed, the nemerteans disperse. Some form mucoid aggregations at protected sites on the exoskeleton; others move to the branchial chamber and gills or transfer to other lobsters. Reproduction occurs almost exclusively on the lobster egg mass, but P. homari appears capable of reproducing on lobster gills if denied access to lobster eggs for extended periods.

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
Keyword(s):  
Sublethal Effects ◽  
Drilling Fluid ◽  
Homarus Americanus ◽  
Diesel Oil ◽  
Chemical Components ◽  
American Lobster ◽  
Drilling Fluids ◽  
Feeding Rates ◽  
Fine Grained ◽  
Larval Stages

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.

scholarly journals Newly Hatched Stage I American Lobster (Homarus americanus) Survival Following Exposure to Physically and Chemically Dispersed Crude Oil

2021 ◽  
Author(s):  
Benjamin de Jourdan ◽  
Tahereh Boloori ◽  
Les Burridge
Keyword(s):  
Environmental Protection Agency ◽  
Native Species ◽  
Toxicity Testing ◽  
Homarus Americanus ◽  
Larval Survival ◽  
Stage I ◽  
Toxicity Tests ◽  
American Lobster ◽  
Atlantic Canada ◽  
Test Species

Abstract Standard model species are commonly used in toxicity tests due to their biological and technical advantages but studying native species increases the specificity and relevance of results generated for the potential risk assessment to an ecosystem. Accounting for intraspecies variability and other factors, such as chemical and physical characterization of test medium, is necessary to develop a reproducible bioassay for toxicity testing with native species. In this study, larval stage I American lobster (Homarus americanus) was selected as the test species, which is native to Atlantic Canada. Toxicity tests were first conducted exposing lobster larvae to a reference toxicant of copper sulfate (CuSO4) and then to physically and chemically dispersed oil. The effect on larval survival was estimated by calculating the median effect concentration (EC50) as 2.54-9.73 mg TPH/L when all trials are considered together. The HC5 or PNEC value was 2.52 mg TPH/L and therefore a narrow difference from the EC50 value. The inter-trial variability (coefficient of variability = 17%) was lower than the US Environmental Protection Agency standard test species of mysid shrimp (Americamysis bahia) and inland silversides (Menidia bervillina). Our results indicate that the described larval lobster bioassay is reliable to produce repeatable results for this commercially important and native species of Atlantic Canada.

Applications of Biochemical Genetics to Aquaculture

1976 ◽  
Vol 33 (4) ◽  
pp. 1108-1119 ◽  
Author(s):  
Dennis Hedgecock ◽  
Robert A. Shleser ◽  
Keith Nelson
Keyword(s):  
Gel Electrophoresis ◽  
Biochemical Analysis ◽  
Natural Populations ◽  
Homarus Americanus ◽  
Larval Survival ◽  
Mendelian Inheritance ◽  
Hybrid Vigor ◽  
American Lobster ◽  
Biochemical Genetics ◽  
Lobster Fishery

American lobster (Homarus americanus) catches are diminishing. More than 90% of the annual catch is 2.2-kg (1-lb) minimum legal size. Females of this size may have produced 10,000 eggs prior to catch, but, with an estimated larval survival of 1/100,000, 10 females are required to reproduce 1 female. The prognosis for the lobster fishery appears poor.Laboratory culture of larval lobsters can achieve more than 60% survival at a cost of about 2¢ per postlarval juvenile. The effectiveness of restocking has never been evaluated.Starch-gel electrophoresis reveals protein differences among individual lobsters: progeny studies confirm Mendelian inheritance of allozymes encoded by five independent genes, Est-2, Idh, Pgi-3, Pgi-4, and Pgm-1. Genetic markers may be determined by biochemical analysis of pereiopod tissue, without killing. Allozyme frequencies have been measured in natural populations (e.g. Pgm-1103 is absent in lobsters from Martha’s Vineyard (MVS), but occurs elsewhere in frequencies of 0.C2). Larvae with rare allozyme genotypes (e.g. Pgm-1100/103 or Pgm-1103/103 at MVS) may be obtained from selected females or produced by appropriate matings. These may be released, and their survival at selected times after release monitored by leg sampling from lobsters of the appropriate age-class. This technique is being used to select diverse parental stocks and produce progeny which may show hybrid vigor. These stocks will be used in developing lobster farming.

scholarly journals Modelling ocean acidification effects with life stage-specific responses alters spatiotemporal patterns of catch and revenues of American lobster, Homarus americanus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Travis C. Tai ◽  
Piero Calosi ◽  
Helen J. Gurney-Smith ◽  
William W. L. Cheung
Keyword(s):  
Climate Change ◽  
Ocean Acidification ◽  
Large Scale ◽  
Life Stage ◽  
Homarus Americanus ◽  
Minimum Size ◽  
Future Climate Change ◽  
American Lobster ◽  
Fishing Pressure ◽  
Size Limits

AbstractOcean acidification (OA) affects marine organisms through various physiological and biological processes, yet our understanding of how these translate to large-scale population effects remains limited. Here, we integrated laboratory-based experimental results on the life history and physiological responses to OA of the American lobster, Homarus americanus, into a dynamic bioclimatic envelope model to project future climate change effects on species distribution, abundance, and fisheries catch potential. Ocean acidification effects on juvenile stages had the largest stage-specific impacts on the population, while cumulative effects across life stages significantly exerted the greatest impacts, albeit quite minimal. Reducing fishing pressure leads to overall increases in population abundance while setting minimum size limits also results in more higher-priced market-sized lobsters (> 1 lb), and could help mitigate the negative impacts of OA and concurrent stressors (warming, deoxygenation). However, the magnitude of increased effects of climate change overweighs any moderate population gains made by changes in fishing pressure and size limits, reinforcing that reducing greenhouse gas emissions is most pressing and that climate-adaptive fisheries management is necessary as a secondary role to ensure population resiliency. We suggest possible strategies to mitigate impacts by preserving important population demographics.

Behavior and Distribution of Larval and Early Jevenile Homarus americanus

1983 ◽  
Vol 40 (12) ◽  
pp. 2184-2188 ◽  
Author(s):  
J. S. Cobb ◽  
T. Gulbransen ◽  
B. F. Phillips ◽  
D. Wang ◽  
M. Syslo
Keyword(s):  
Stage Iv ◽  
Homarus Americanus ◽  
American Lobster ◽  
Substrate Selection ◽  
Fourth Stage ◽  
Shallow Sea ◽  
Behavioral Observations

Field behavioral observations and plankton tows show that American lobster (Homarus americanus) larvae are concentrated in downwellings characteristic of shallow sea fronts. Stage IV lobsters swimming at the surface avoided floating weeds and sticks. Seventy percent of laboratory-reared fourth stage lobsters swam near the surface for more than a minute when released but only 25% of fifth stage lobsters did so. When early fourth stage lobsters encountered bottom, they did not remain long in one place, but late fourth and early fifth stage lobsters began to burrow. Late fourth and early fifth stage lobsters were less likely to return to the surface when they reached the bottom. If the bottom was unsuitable (featureless sand), the lobsters resumed swimming. These behaviors appear to be an appropriate mechanism for substrate selection during settlement.

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