The lethality of the cypermethrin formulation Excis® to larval and post-larval stages of the American lobster (Homarus americanus)

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

THE EFFECTS OF CRUDE OIL ON LARVAE OF LOBSTER HOMARUS AMERICANUS

1977 ◽  
Vol 1977 (1) ◽  
pp. 569-573
Author(s):  
Joseph M. Forns
Keyword(s):  
Crude Oil ◽  
Mass Culture ◽  
Homarus Americanus ◽  
Behavioral Characteristics ◽  
American Lobster ◽  
Larval Stages ◽  
Fourth Larval Stage ◽  
Flow Through ◽  
Oil Exposure ◽  
South Louisiana

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.

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.

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 Experimental evidence for concentration-dependence and intra-specific variation of movement behaviour in American lobster (Homarus americanus) larvae

2016 ◽  
Author(s):  
Eric J Pedersen ◽  
Ryan R.E. Stanley ◽  
Paul V.R. Snelgrove ◽  
Frederic Guichard
Keyword(s):  
Vertical Distribution ◽  
Substantial Reduction ◽  
Homarus Americanus ◽  
American Lobster ◽  
High Concentration ◽  
Larval Stages ◽  
Larval Behaviour ◽  
Low Concentrations ◽  
Environmental Responses ◽  
Newly Hatched Larvae

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.

scholarly journals Larval Development of the European Lobster and How Small Heterochronic Shifts Lead to a More Pronounced Metamorphosis

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Marie A. I. N. Rötzer ◽  
Joachim T. Haug
Keyword(s):  
Larval Stage ◽  
Stage Iv ◽  
Extreme Case ◽  
Homarus Americanus ◽  
Stage Iii ◽  
American Lobster ◽  
Factors Affecting ◽  
European Lobster ◽  
Larval Stages ◽  
Two Factors

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.

scholarly journals Experimental evidence for concentration-dependence and intraspecific variation of movement behaviour in American lobster (Homarus americanus) larvae

2017 ◽  
Vol 95 (10) ◽  
pp. 759-770
Author(s):  
Eric J. Pedersen ◽  
Ryan R.E. Stanley ◽  
Paul V.R. Snelgrove ◽  
Frédéric Guichard
Keyword(s):  
Substantial Reduction ◽  
Homarus Americanus ◽  
American Lobster ◽  
High Concentration ◽  
Larval Stages ◽  
Larval Behaviour ◽  
Low Concentrations ◽  
Marine Larvae ◽  
Environmental Responses ◽  
Newly Hatched Larvae

Predicting dispersal paths of marine larvae with extended pelagic durations, such as American lobster (Homarus americanus H. Milne Edwards, 1837), 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, then 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 both in newly hatched larvae and in postlarvae, but not in intermediate larval stages. 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.

Factors Influencing the Size of American Lobster (Homarus americanus) Stocks Along the Atlantic Coast of Nova Scotia, Gulf of St. Lawrence, and Gulf of Maine: A New Synthesis

1983 ◽  
Vol 40 (2) ◽  
pp. 168-184 ◽  
Author(s):  
Gareth C. Harding ◽  
Ken F. Drinkwater ◽  
W. Peter Vass
Keyword(s):  
Nova Scotia ◽  
Gulf Of Maine ◽  
Rapid Development ◽  
Atlantic Coast ◽  
Homarus Americanus ◽  
American Lobster ◽  
Georges Bank ◽  
Larval Recruitment ◽  
Larval Stages ◽  
Recruitment Failure

The general aspects of fluctuating American lobster (Homarus americanus) stocks are considered in an attempt to identify common principles controlling lobster populations in the Gulf of Maine, Gulf of St. Lawrence, and the Atlantic coast of Nova Scotia. Inshore fishing mortality is known to be precariously high in both Canadian and American waters yet only in the central Northumberland Strait region and along the Atlantic coast of Nova Scotia are stocks experiencing steep declines. Existing regulations allow fishing of lobsters well below the size at which maturity can be expressed. In western and central Northumberland Strait female lobsters are not protected by the 'berried' law because of the timing of the fishing season. Climatic change, expressed as sea-surface temperature, is closely associated with the success of lobster recruitment in the Gulf of Maine, but nowhere else. Huntsman's hypothesis that warm surface water of sufficient duration is essential for the successful completion of the larval stages of the lobster is found to have wide application. Warmer waters are also found to have a preponderance of plankton in the size categories required for feeding by the first two larval stages. Both the southern Gulf of St. Lawrence and the southwestern Gulf of Maine, including Georges Bank, are believed to be prolific nursery grounds for the early larval lobsters because warm water with plenty of food stimulates rapid development and settling. We calculated that larvae released on Georges Bank supply recruits to southern Nova Scotia, Bay of Fundy, and Maine, whereas some larvae from the southern Gulf of St. Lawrence are thought to settle as far as Cape Breton Co., N.S., and before the closure of the Strait of Canso, Guysborough Co., N.S. The past importance of lobster recruitment to the Atlantic coast of Nova Scotia through the Strait of Canso is estimated to have been as high as 60% of the average landings in Chedabucto Bay during the 11 best years of this fishery. The failure of the Atlantic coast lobster fishery off Nova Scotia is believed to have been initiated by a larval recruitment failure caused by the synchronous closure of the Strait of Canso and the start of a general climatic cooling. Possibly a critical temperature was reached along the Atlantic coast of Nova Scotia in the 1950s below which larval survival is much reduced by the shortened season. Reduced lobster abundance along the Atlantic coast of Nova Scotia may have contributed to the imbalance in the benthic ecosystem in which an uncontrolled urchin population consumed the kelp beds and until recently greatly reduced the primary production input to the system.Key words: American lobster, Homarus americanus; stocks, recruitment, ecology, larval transport

Larval development in the American lobster: changes in metabolic activity and the O:N ratio

1979 ◽  
Vol 57 (10) ◽  
pp. 1845-1848 ◽  
Author(s):  
Judith M. Capuzzo ◽  
Bruce A. Lancaster
Keyword(s):  
Larval Development ◽  
Ammonia Excretion ◽  
Homarus Americanus ◽  
American Lobster ◽  
Energy Yield ◽  
Larval Stages ◽  
O:N Ratio ◽  
Significant Difference ◽  
Principal Source ◽  
Carbohydrate Catabolism

The rates of oxygen consumption under conditions of feeding and starvation and the rates of ammonia excretion after feeding increased with each larval stage of the American lobster (Homarus americanus Milne Edwards) and decreased with the first postlarval stage. There was no significant difference in the O:N ratio of the first three larval stages (~26.5), but a significant reduction (P < 0.01) was measured among stages IV and V. It appears that, whereas protein catabolism may be the principal source of energy, some of the energy yield during larval development is from lipid or carbohydrate catabolism; the use of the latter substrates is diminished in the last larval and first postlarval stages.

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