Interaction of Temperature and Photoperiod in the Regulation of Spawning by American lobsters (Homarus americanus)

1989 ◽  
Vol 46 (1) ◽  
pp. 145-148 ◽  
Author(s):  
D. E. Aiken ◽  
S. L. Waddy
Keyword(s):  
Seawater Temperature ◽  
Homarus Americanus ◽  
Mature Female ◽  
Regulatory Role ◽  
American Lobster ◽  
Conflicting Information ◽  
Photoperiod Control ◽  
Short Days

Various studies have yielded conflicting information on the role of photoperiod in the regulation of spawning by the American lobster (Homarus americanus). Some have indicated a requirement for short days followed by long days, while others have suggested that there is no photoperiod requirement. To resolve the question of photoperiod control, we exposed mature female lobsters to various combinations of temperature and photoperiod for 1 yr starting in December and found that there was no requirement for spring photoperiod under local winter seawater temperature (0–5 °C, but when winter seawater temperature was maintained at 10–17 °C, spawning came under the influence of spring photoperiod. It therefore appears that vitellogenesis and spawning of nearshore lobster populations are normally regulated by seasonal seawater temperature but that photoperiod can assume a regulatory role if the winter seawater temperature remains abnormally high.

Oocyte Maturation and Spawning in Wild American Lobsters (Homarus americanus): Lack of Evidence for Significant Regulation by Photoperiod

1986 ◽  
Vol 43 (7) ◽  
pp. 1451-1453 ◽  
Author(s):  
D. E. Aiken ◽  
S. L. Waddy
Keyword(s):  
Oocyte Maturation ◽  
East Coast ◽  
Homarus Americanus ◽  
Mature Female ◽  
American Lobster ◽  
Ovarian Maturation ◽  
Long Day ◽  
Autumnal Equinox ◽  
Spawning Time ◽  
Short Days

The literature indicates that spawning in the American lobster (Homarus americanus) requires exposure to short days followed by long days, but our previous experiments with mature female lobsters showed no such requirement. To reevaluate the reported photoperiod requirement and to determine whether a photoperiod stimulus for ovarian maturation might occur well before the current spawning season, we held wild-caught mature Gulf of St. Lawrence females on either long (LD 16:8) or short (LD 1:23) days starting at the autumnal equinox. Females held on both short and long days spawned at the normal time the following July, indicating no effect of photoperiod even 10 mo before normal spawning time. This study extends previous work by showing that Gulf of St. Lawrence lobsters held on typical East Coast seawater temperatures will spawn at the normal time without being exposed to either short-day or long-day photoperiod between 22 September and the following July.

Effects of Reproduction upon Molting and Growth in Female American Lobsters (Homarus americanus)

1988 ◽  
Vol 45 (5) ◽  
pp. 805-821 ◽  
Author(s):  
K. Nelson ◽  
D. Hedgecock ◽  
W. Borgeson
Keyword(s):  
Growth Rates ◽  
Homarus Americanus ◽  
Control Group ◽  
American Lobster ◽  
Cycle Duration ◽  
Female Size ◽  
Molt Cycle ◽  
Young Females ◽  
Long Day ◽  
Short Days

American lobster (Homarus americanus) females characteristically extrude eggs (E) in the summer of the year following a summer or autumn molt (M), but young females may extrude in the same year. The subsequent M is delayed until after hatching, resulting in the former case in a 2-yr reproductive molt cycle, measuring from M to M. Adult female lobsters were exposed to periods of short days (8 h light: 16 h dark) followed by long day onset (L) (16 h light: 8 h dark) at different times with respect to M, or as controls were kept under continuous long-day conditions. In this way were generated molt cycles with delayed or undelayed extrusions, as well as ones with incomplete vitellogeneses resulting from too-long delayed L, and molt cycles in which vitrellogenesis did not begin (control group). Delayed L results in delayed E and M, as measured either in days or in day-degrees above 6 °C. An incompleted vitellogenesis following a too-long delayed L changes neither the duration of the molt cycle nor its characteristic positive correlation with female size; the duration of molt cycles containing either delayed or undelayed E appears in contrast to become independent of size. Intermolt intervals following prior E are shorter than those following anovulatory cycles. Retention of the clutch to hatching is associated with an additional increment to the intermolt interval. The results suggest that following E, a "reproductive" program replaces the "somatic" program of control of molt cycle duration. Incompleted vitellogeneses are associated with significantly smaller molt increments and growth rates than in the evidently avitellogenic continuous long-day control group, even though intermolt duration and its relation to size remain the same. Growth rates of molt cycles containing incompleted vitellogeneses are significantly higher than ones containing E only if that is delayed. Differential dependence of molt cycle duration and growth rate measures upon size and temperature indicate that molting and growth are distinct and rather independently controlled processes in adult lobsters, however tightly linked they may be in juveniles. Implications for molting and reproduction in the natural environment are discussed.

Detection of Dissolved Substances by the American Lobster (Homarus americanus) and Olfactory Attraction between Lobsters

1970 ◽  
Vol 27 (8) ◽  
pp. 1371-1378 ◽  
Author(s):  
D. W. McLeese
Keyword(s):  
Amino Acids ◽  
Sex Attractant ◽  
Homarus Americanus ◽  
Mature Female ◽  
American Lobster ◽  
High Concentration ◽  
Beta Alanine ◽  
Sex Attractant Pheromone ◽  
Low Concentrations ◽  
Attractant Pheromone

Of 17 amino acids and other organic compounds tested at high concentration, 13 elicited feeding and walking responses in lobsters significantly greater than those elicited by seawater controls, but only 7 of 29 were stimulatory at low concentrations (alanine, beta alanine, glutamic acid, proline, succinic and malic acids, and tyrosine). Fourteen of 15 mixtures of 2–9 amino acids were stimulatory. There may have been potentiation in mixtures with cysteine HCl, lysine, glycine HCl, and methionine and antagonism in some with alanine and arginine. Freshly prepared seawater extracts of cod, shrimp, and lobster muscle were more stimulatory than any of the compounds or mixtures.Male lobsters responded more frequently to water from a tank with a recently moulted mature female lobster than to water from a tank with a nonmoulted mature female or a moulted or a nonmoulted male. It is possible that moulted females release a sex attractant (pheromone).

scholarly journals Sound detection by the American lobster (Homarus americanus)

2021 ◽  
Vol 224 (6) ◽  
pp. jeb240747
Author(s):  
Youenn Jézéquel ◽  
Ian T. Jones ◽  
Julien Bonnel ◽  
Laurent Chauvaud ◽  
Jelle Atema ◽  
...  
Keyword(s):  
Marine Invertebrates ◽  
Seawater Temperature ◽  
Low Frequency ◽  
Sensory Ecology ◽  
Homarus Americanus ◽  
Auditory Evoked Potential ◽  
American Lobster ◽  
Auditory Thresholds ◽  
Sound Detection ◽  
The Brain

ABSTRACTAlthough many crustaceans produce sounds, their hearing abilities and mechanisms are poorly understood, leaving uncertainties regarding whether or how these animals use sound for acoustic communication. Marine invertebrates lack gas-filled organs required for sound pressure detection, but some of them are known to be sensitive to particle motion. Here, we examined whether the American lobster (Homarus americanus) could detect sound and subsequently sought to discern the auditory mechanisms. Acoustic stimuli responses were measured using auditory evoked potential (AEP) methods. Neurophysiological responses were obtained from the brain using tone pips between 80 and 250 Hz, with best sensitivity at 80–120 Hz. There were no significant differences between the auditory thresholds of males and females. Repeated controls (recordings from deceased lobsters, moving electrodes away from the brain and reducing seawater temperature) indicated the evoked potentials' neuronal origin. In addition, AEP responses were similar before and after antennules (including statocysts) were ablated, demonstrating that the statocysts, a long-proposed auditory structure in crustaceans, are not the sensory organs responsible for lobster sound detection. However, AEPs could be eliminated (or highly reduced) after immobilizing hairfans, which cover much of lobster bodies. These results suggest that these external cuticular hairs are likely to be responsible for sound detection, and imply that hearing is mechanistically possible in a wider array of invertebrates than previously considered. Because the lobsters' hearing range encompasses the fundamental frequency of their buzzing sounds, it is likely that they use sound for intraspecific communication, broadening our understanding of the sensory ecology of this commercially vital species. The lobsters' low-frequency acoustic sensitivity also underscores clear concerns about the potential impacts of anthropogenic noise.

Growth of juvenile American lobster Homarus americanus in a changing environment

2016 ◽  
Vol 557 ◽  
pp. 177-187 ◽  
Author(s):  
MD McMahan ◽  
DF Cowan ◽  
Y Chen ◽  
GD Sherwood ◽  
JH Grabowski
Keyword(s):  
Homarus Americanus ◽  
American Lobster ◽  
Changing Environment

Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

2020 ◽  
Vol 641 ◽  
pp. 159-175
Author(s):  
J Runnebaum ◽  
KR Tanaka ◽  
L Guan ◽  
J Cao ◽  
L O’Brien ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Management Tool ◽  
American Lobster ◽  
Suitable Habitat ◽  
Climate Conditions ◽  
Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

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