Survival and Growth of Juvenile American Lobsters (Homarus americanus) After Eyestalk Ablation

1979 ◽  
Vol 36 (1) ◽  
pp. 93-97 ◽  
Author(s):  
D. J. Trider ◽  
E. G. Mason ◽  
J. D. Castell
Keyword(s):  
Weight Gain ◽  
Brine Shrimp ◽  
Homarus Americanus ◽  
American Lobster ◽  
Eyestalk Ablation ◽  
Adequate Diet ◽  
Stage Juvenile ◽  
Survival And Growth ◽  
The Mean ◽  
And Control

The effect of size at the time of ablation on postoperative survival was assessed by removing the eyestalk from 4th, 5th, and 6th stage juvenile American lobsters (Homarus americanus) 6 d postmolt. The 6th stage juveniles exhibited significantly higher survival (72.8%) through three postoperative molts than the 5th or 4th stage lobsters (45 and 30% survival, respectively). Survival of control lobsters through the same number of molts was 90%. The feeding of a nutritionally adequate diet (frozen brine shrimp) was of prime importance with regard to survival of both ablated and control lobsters. The mean percent total weight gains for these three postablation molts were 610, 571, and 642% for 4th, 5th, and 6th stage lobsters, respectively, while the weight gain for control lobsters was 407%. The data suggest that eyestalk ablation should not be performed earlier than 6th stage for maximum survival and growth. Key words: eyestalk ablation, American lobster, survival, growth

Determinants of Postmolt Size in the American Lobster (Homarus americanus). II. Folding of Premolt Cuticle

1994 ◽  
Vol 51 (8) ◽  
pp. 1774-1779 ◽  
Author(s):  
Jin-Hua Cheng ◽  
Ernest S. Chang
Keyword(s):  
Homarus Americanus ◽  
Size Increase ◽  
American Lobster ◽  
Eyestalk Ablation ◽  
Before And After ◽  
Rearing Condition

The effects of eyestalk ablation, regeneration, and rearing condition on the size of new cuticles before and after expansion were studied in juvenile Homarus americanus. Both eyestalk-ablated and intact lobster grew larger in large spaces than in small spaces. In contrast, regeneration reduced molt increment. Despite large differences in molt increment (percentage of size increase during a molt) among experimental groups, the percentage of postmolt size increase that could be accounted for by unfolding of the new cuticle was large and constant in each group. In addition, transferring freshly molted lobster to dilute seawater did not produce any further size increase but instead caused cuticle breakage in some animals. We conclude that molt increment in lobster is determined by regulating the size of the cuticle before ecdysis. The size of the postmolt cuticle is primarily a result of unfolding of the new, previously folded cuticle.

Effects of eyestalk ablation upon water relations in the American lobster,Homarus americanus

1987 ◽  
Vol 244 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Susan A. Jackson ◽  
Marilyn J. Bruce ◽  
Ernest S. Chang ◽  
James S. Clegg
Keyword(s):  
Water Relations ◽  
Homarus Americanus ◽  
American Lobster ◽  
Eyestalk Ablation

scholarly journals In vivo efficacy of lasalocid and pyrimethamine treatments against Anophryoides haemophila, a ciliate pathogen of American lobster Homarus americanus

2017 ◽  
Vol 54 (4) ◽  
pp. 297
Author(s):  
F. ATHANASSOPOULOU (Φ. ΑΘΑΝΑΣΟΠΟΥΛΟΥ) ◽  
A. E. CRIBB ◽  
R. J. CAWTHORN ◽  
R. MacMILLAN ◽  
G. BALDAS (Γ. ΜΠΑΛΝΤΑΣ)
Keyword(s):  
Effective Treatment ◽  
Homarus Americanus ◽  
Uninfected Control ◽  
Control Group ◽  
American Lobster ◽  
In Vivo Efficacy ◽  
Repeated Doses ◽  
The Mean

Lasalocid and pyrimethamine was administered to American lobsters infected with A. haemophila. Lasalocid was found to be toxic and acute mortality was observed, when administered in vivo in both infected and uninfected lobsters. Pyrimethamine was found very efficient to treat these ciliates at repeated doses. The mortality was very low and the mean haemocyte counts remained higher than the uninfected control group. The drug seems to delay the appearance of the ciliates in the haemolymph and to lower the spread of these parasites in the epipodite and the hepatopancreas. In uninfected animals treated with this drug, haemocyte counts were similar to uninfected control group. Furthermore, no pathology was observed, when the drug was administered to uninfected lobsters. Since there is no effective treatment for the control of bumper car disease, on the basis of the results of the present study, we suggest that pyrimethamine is a good drug for the treatment of A. haemoplila infection in lobsters.

The Effect of Diet on Weight Gain, Shell Hardness, and Flavor of New-Shell American Lobster,Homarus americanus

1997 ◽  
Vol 7 (4) ◽  
pp. 69-77 ◽  
Author(s):  
Darrell W. Donahue ◽  
Robert C. Bayer ◽  
Therese M. Work ◽  
John G. Riley
Keyword(s):  
Weight Gain ◽  
Homarus Americanus ◽  
American Lobster

Cholesterol Requirements of Juvenile American Lobster (Homarus americanus)

1975 ◽  
Vol 32 (8) ◽  
pp. 1431-1435 ◽  
Author(s):  
John D. Castell ◽  
Edgar G. Mason ◽  
Jane F. Covey
Keyword(s):  
Brine Shrimp ◽  
Control Diet ◽  
Dietary Cholesterol ◽  
Dry Weight ◽  
Homarus Americanus ◽  
American Lobster ◽  
Cod Liver Oil ◽  
Mineral Salts ◽  
Growth And Survival ◽  
Feeding Trials

In preliminary feeding trials with juvenile American lobsters (Homarus americanus) there were some differences in growth and survival that appeared to be related to deletion or addition of cod liver oil, mineral salts, vitamins, and glucosamine. However, the results were questionable due to deficiency of dietary cholesterol. Only when 1% cholesterol was added to the control diet was growth and survival achieved similar to that of lobsters fed brine shrimp. The optimum or required level of cholesterol was found to be approximately 0.5% of the dry weight of the diet.

Temperature and Lobster, Homarus americanus, Yield Relationships

1991 ◽  
Vol 48 (11) ◽  
pp. 2073-2082 ◽  
Author(s):  
A. Campbell ◽  
D. J. Noakes ◽  
R. W. Elner
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
East Coast ◽  
Homarus Americanus ◽  
Fishing Effort ◽  
Sea Surface ◽  
Time Series Models ◽  
American Lobster ◽  
Sea Temperature ◽  
Survival And Growth

Commercial landings of American lobster (Homarus americanus) have increased dramatically in many areas along the east coast of Canada since the late 1970's. Average annual sea surface temperatures (SST) were analysed to test if lobster landings were related to changes in the marine environment. Time series models were fitted to lobster landings and SST data from Maine (USA), Halifax County (Nova Scotia), and Charlotte County (New Brunswick). Including temperature in the models improved forecasting ability for lobster catches for Maine and Halifax but not Charlotte. In Maine, lobster landings in year t were related to SST in year t. In Halifax, however, landings were related to SST in the previous 4 yr but not by SST of the current year. Lower fishing effort levels for Halifax compared with Maine probably extended the yield from strong year-classes through a number of years. We surmise that an increase in sea temperature near Halifax during the early 1980's increased the survival and growth rates of lobster juveniles. This provided a strong pulse of recruits to the fishery throughout coastal Nova Scotia during the mid- to late 1980's. Similar increases in temperature and landings were not observed for Maine and Charlotte.

Olfactory Recognition of Urine Signals in Dominance Fights Between Male Lobster, Homarus Americanus

Behaviour ◽  
1998 ◽  
Vol 135 (6) ◽  
pp. 719-730 ◽  
Author(s):  
Jelle Atema ◽  
Christa Karavanich
Keyword(s):  
Homarus Americanus ◽  
Chemical Signals ◽  
Male Dominance ◽  
American Lobster ◽  
Dominance Relationship ◽  
Dominance Hierarchies ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Dominant Animal ◽  
And Control

AbstractThe maintenance of dominance hierarchies in the American lobster (Homarus americanus) is based on recognition of the dominant animal by the loser of a recent fight. It is hypothesized that chemical signals are the basis of this recognition. Adult male lobsters were paired for initial boxing matches between unfamiliar animals. The same pairs were re-matched for 3 more consecutive fights. In the first experiment, treatment animals had their primary olfactory receptor cells of the lateral and medial antennules lesioned before fights 2-4 and control animals received sham lesions. The durations of fights 2-4 for control pairs were significantly shorter than the durations of fights between lesioned animals. In the second experiment, male pairs were again allowed to establish a dominance relationship in a first fight. During second fights, urine release by both animals was prevented by the use of catheters in treatment animals while control pairs wore sham catheters. Again, durations of the second fights of control animals were significantly shorter than those of treatment animals. Together, these experiments indicate that urine-carried chemical signals, perceived by the antennules, reduce the duration and aggression of male dominance fights on subsequent days because the loser of the first fight backs off almost immediately when he smells the urine of the known dominant.

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