Occurrence of Histriobdella homari (Annelida: Polychaeta) on the American lobster in the Canadian Maritimes

1985 ◽  
Vol 63 (2) ◽  
pp. 392-395 ◽  
Author(s):  
John Brattey ◽  
Alan Campbell
Keyword(s):  
Homarus Americanus ◽  
High Abundance ◽  
American Lobster ◽  
Egg Hatching ◽  
Egg Masses ◽  
Beneficial Effects ◽  
Gill Filaments

Examination of 870 trap-caught lobsters, Homarus americanus, indicated that Histriobdella homari, an epizoic microphagous cleaning symbiont, was common and widely distributed on lobster populations in Canadian Maritime waters during 1980–1981. Prevalence (percent lobsters infected) and abundance (mean number of H. homari per lobster) ranged from 39.6 to 100% and 4.8 to 80.5, respectively. The polychaete was more abundant on ovigerous females than on male or nonovigerous female lobsters. The distribution of H. homari among lobsters was aggregated with a maximum of 669 H. homari on a lobster. In most infestations, the polychaete is probably beneficial to the lobster by removing encrusting microorganisms from the gill filaments and egg masses. However, on the few lobsters that have high abundance of greater than 200 H. homari per individual, the beneficial effects may be lost, since the polychaetes may reduce repiratory flow and success of egg hatching.

Early spring egg hatching by the American lobster (Homarus americanus) linked to rising water temperature in autumn

2020 ◽  
Vol 77 (5) ◽  
pp. 1685-1697
Author(s):  
Marthe Larsen Haarr ◽  
Michel Comeau ◽  
Jöel Chassé ◽  
Rémy Rochette
Keyword(s):  
Temporal Trends ◽  
Homarus Americanus ◽  
Early Spring ◽  
Life Cycles ◽  
Rate Of Change ◽  
American Lobster ◽  
Temperature Dependent ◽  
Egg Hatching ◽  
Hatching Time ◽  
Phenological Changes

Abstract Increasing ocean temperatures may affect life cycles of organisms whose biological processes are temperature-dependent. Our objective was to determine whether hatching time of American lobster (Homarus americanus), which has a 2-year reproductive cycle, has advanced in the southern Gulf of St Lawrence, Canada, in response to rising temperature. We investigated temporal trends in hatching time 1989–2014 using fisheries monitoring data. We considered two metrics: the first week of the year when ovigerous females with prehatch or hatching clutches were observed [onset-of-hatching (OH)] and the rate of change in the ratio of females with prehatch/hatching vs. developing clutches each spring fishing season [rate of clutch development (RCD)]. OH advanced by 5 weeks and RCD increased by 40% on average. Comparisons of OH and RCD to cumulative degree-days going back 2 years prior to hatching suggested an effect of higher fall temperatures during early ovarian and embryonic development. The advancement of hatching time in response to environmental conditions 6–18 months before hatching occurs could lead to a mismatch with larval prey species with shorter life cycles. These findings highlight the importance of monitoring phenology of fished species and the need for further research into potential impacts of phenological changes.

Salinity Tolerance and Osmoregulation in the Nemertean Pseudocarcinonemertes homari, an Egg Predator of American Lobster, Homarus americanus

1991 ◽  
Vol 48 (2) ◽  
pp. 209-214 ◽  
Author(s):  
G. Charmantier ◽  
M. Charmantier-Daures ◽  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Salinity Tolerance ◽  
Stage Iv ◽  
Homarus Americanus ◽  
Index Formula ◽  
American Lobster ◽  
Egg Masses ◽  
Egg Predator

The salinity tolerance and osmoregulation of Pseudocarcinonemertes homari were determined to develop a method for elimination of this nemertean from egg masses of American lobster, Homarus americanus. The lower and upper lethal salinities (LS50) for nemerteans are 11 and 45‰ at 7 °C and 19 and 37‰ at 14.5 °C. Immersion in freshwater was lethal in 4 min or less, depending on temperature. The nemerteans hyperosmoconformed over the range 10–1600 mosm∙kg−1. Lobster eggs (eye index [Formula: see text]) survived for 2–8 h when immersed in freshwater. Ovigerous lobster were not affected by a 5-min immersion in freshwater and were able to withstand at least 30 min if only the abdomen was immersed. Lobster eggs hatched and larvae developed normally up to at least stage IV, even after a 30-min freshwater immersion. These results suggest that nemerteans could be eliminated from American lobster by immersing their abdomen and attached eggs in freshwater for 5 min and immersing the entire lobster for an additional 5 min.

Geographic Distribution and Seasonal Occurrence of the Nemertean Pseudocarcinonemertes homari on the American Lobster, Homarus americanus

1985 ◽  
Vol 42 (2) ◽  
pp. 360-367 ◽  
Author(s):  
J. Brattey ◽  
A. Campbell ◽  
A. E. Bagnall ◽  
L. S. Uhazy
Keyword(s):  
Homarus Americanus ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Wild Populations ◽  
Intensity Of Infection ◽  
Egg Masses ◽  
Mean Intensity ◽  
Life History Stages ◽  
Egg Incubation ◽  
The Impact

Examination of 1041 trap-caught lobsters from the Bay of Fundy, Grand Manan, Browns and German Banks, south and east Nova Scotia, and Northumberland Strait indicated that Pseudocarcinonemertes homari occurs on American lobsters, Homarus americanus, throughout Canadian Maritime waters. Male lobsters were rarely infected and ovigerous females generally had a higher prevalence (percentage infected) and mean intensity of infection (number of nemerteans per infected lobster) than nonovigerous females. Sexually immature nemerteans were found on male and nonovigerous female lobsters, but all P. homari life history stages including brood sacs occurred on ovigerous lobsters. No seasonal trends were evident on ovigerous lobsters caught near Grand Manan; prevalence was consistently high (60–93%) and mean intensity ± SE was variable (15 ± 4.0 to 86 ± 63.1). The nemertean developed to maturity on ovigerous lobsters, reproduced on the host egg masses throughout the year, and appeared to produce three generations during a lobster egg incubation period. When lobsters completed egg incubation, nemertean reproduction ceased and some nemerteans either died, left the lobster, or perhaps were shed at molting. Prevalence and mean intensity increased with the size of ovigerous lobsters, and the distribution of nemerteans among ovigerous lobsters was highly aggregated. Ovigerous lobsters infected with >200 nemerteans had extensively damaged egg masses, but were rarely encountered (5 of 291). The impact of P. homari on the egg mortality of wild populations of H. americanus is unknown.

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.

Valorization of American lobster ( Homarus americanus ) cooking waters: preparation and characterization of a food ingredient

2021 ◽  
Author(s):  
Ariane Tremblay ◽  
Ronan Corcuff ◽  
Charles Goulet ◽  
Samuel B. Godefroy ◽  
Alain Doyen ◽  
...  
Keyword(s):  
Homarus Americanus ◽  
American Lobster ◽  
Food Ingredient

Predicting the winning or losing of symmetrical contests in the American lobster Homarus americanus (Milne-Edwards)

1997 ◽  
Vol 217 (1) ◽  
pp. 19-29 ◽  
Author(s):  
C. Vye ◽  
J.S. Cobb ◽  
T. Bradley ◽  
J. Gabbay ◽  
A. Genizi ◽  
...  
Keyword(s):  
Homarus Americanus ◽  
American Lobster
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