Laboratory and Field Tests of Modified Sphyrion Tags on Lobsters (Homarus americanus)

1970 ◽  
Vol 27 (2) ◽  
pp. 257-264 ◽  
Author(s):  
D. J. Scarratt
Keyword(s):  
Carapace Length ◽  
Field Tests ◽  
Homarus Americanus ◽  
Poor Survival ◽  
Internal Organs ◽  
Fishing Season ◽  
Tag Loss

Mortalities of lobsters held in the laboratory and tagged with sphyrion tags inserted dorsally between the carapace and abdomen (subcarapace tag) and between the second and third abdominal segments (abdomen tag) did not differ significantly. Premoult tag loss was negligible. The subcarapace tag was retained significantly better through moulting.Returns of subcarapace-tagged and abdomen-tagged lobsters released on the fishing grounds in June, 11 weeks before the August 10 opening of the fishing season, were lower than returns of carapace-tagged lobsters released in early August. More subcarapace-tagged than abdomen-tagged lobsters were returned, and a higher proportion had moulted. Growth was comparable to that reported in the literature. Few lobsters were recaptured during the following fishing season, 14–16 months after liberation, and none subsequently. Returns from lobsters less than 63.5 mm carapace length (sublegal) when tagged were extremely low. Poor survival may be related in part to time of release. Some injury to internal organs may occur with both tags. The subcarapace tag is clearly superior but may be of limited value in the field for lobsters below 63.5 mm carapace length.

Multiple Fertilization and Consecutive Spawning in Large American Lobsters, Homarus americanus

1986 ◽  
Vol 43 (11) ◽  
pp. 2291-2294 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Body Size ◽  
Carapace Length ◽  
Homarus Americanus ◽  
Large Female ◽  
Bay Of Fundy ◽  
Relative Fecundity ◽  
Logarithmic Relationship

Large female American lobsters, Homarus americanus (> 120 mm carapace length), maintained at nearshore Bay of Fundy temperatures often spawn twice without an intervening molt (consecutive spawning). Consecutive spawning occurs in two forms: successive-year (spawning in two successive summers, a molt in the first and fourth years) and alternate-year (spawning in alternate summers, a molt in the first and fifth years). In both types, females often are able to fertilize the two successive broods with the sperm from a single insemination (multiple fertilization). Twenty of 21 large females that were held for up to 13 yr displayed one of these types of consecutive spawning. Consecutive spawning and multiple fertilization enable large lobsters to spawn more frequently over the long term than their smaller counterparts. This, combined with the logarithmic relationship between body size and numbers of eggs produced, means that very large lobsters have a much greater relative fecundity than previously thought.

Size–Maturity Relationships and Related Observations in Newfoundland Populations of the Lobster (Homarus americanus)

1980 ◽  
Vol 37 (6) ◽  
pp. 945-956 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Carapace Length ◽  
Size Range ◽  
Sex Ratios ◽  
Weight Ratio ◽  
Homarus Americanus ◽  
Spawning Season ◽  
Length Ratio ◽  
Maturity Indices

Female maturity ogives for five Newfoundland populations of the lobster (Homarus americanus) gave 50% maturities ranging from 71- to 76-mm carapace length. Sizes at which distinct inflections (indicating onset of maturity) and asymptotes (indicating 100% mature) are present in the abdomen width/carapace length ratio vs. carapace length relationships coincide with the smallest ovigerous and largest immature specimens, respectively, observed in those particular samples. Inflection in the crusher claw weight/whole weight ratio vs. carapace length relationships (used in this paper to indicate onset of maturity in males) occurred at larger sizes than inflections in the abdomen width/carapace length ratios of females.The percentage of nonovigerous females that spawn in a given year generally increases with increasing size. The highest percentage of nonovigerous females tagged with sphyrion tags prior to the spawning season that were ovigerous when recaptured 10–12 mo later was 83.8%. The percentage of ovigerous females with new shells (i.e. molted and spawned in same year) varied between areas and years and ranged from 0 to 38.5% of the total number of ovigerous females in fall samples. The percentage of ovigerous females in samples also varied between areas and years and ranged from 2.6 to 30.4% of the total number of females greater than the size at 50% maturity. In general a greater percentage of females was ovigerous at sizes between the size at 50% maturity and 80 mm (largest subcommercial size) than at commercial sizes.In a sample of nonovigerous females, the size range at which 50% were fertilized (76–80 mm) coincided closely with the size at 50% maturity (75 mm) for the area.At subcommercial sizes (< 81 mm) the sexes were approximately equally represented in fall trap-caught samples but females heavily outnumbered males in diver-caught samples taken over the same period. At commercial sizes, however, males heavily outnumbered females in the trap-caught samples while in diver-caught samples the sexes were equally represented.Key words: lobster (Homarus americanus), maturity ogives, maturity indices, percent ovigerous, sex ratios

Biological tags as moult indicators in Panulirus cygnus (George)

1997 ◽  
Vol 48 (8) ◽  
pp. 959 ◽  
Author(s):  
R. Melville-Smith ◽  
J. B. Jones ◽  
R. S. Brown
Keyword(s):  
Carapace Length ◽  
Size Range ◽  
Field Trials ◽  
Size Category ◽  
Fishing Season ◽  
Panulirus Cygnus ◽  
Biological Tags

Laboratory and field trials were employed to examine the feasibility of using biological tags as moult indicators. Twenty-four animals were tagged with epidermal implants and held in aquaria for 2 years and 8 months before the tags were removed. Five tags failed to form useful cysts and one tag was damaged during processing. The remaining 18 lobsters moulted between three and six times, with this moulting record being accurately verified by 15 of the biological tags and incorrectly interpreted (by one moult) in one case. Two tags produced inconclusive results. Biological tags were tested in the field in the Fremantle area, with 132 animals being recaptured out of 1336 tagged. Eleven tags proved impossible to read, eight failed to form cysts, and the balance recorded up to six moults during the release period. Animals in the size range 60–80 mm carapace length (CL) recorded two moults per year, one in February–April and a second before the mid-November start to the fishing season. Females grew significantly less per moult than did males in the same size category (60–85 mm CL), and both sexes showed significantly smaller increments for animals ≥85 mm CL at release.

scholarly journals Exploitation status of Lobster on Kebumen Waters

2011 ◽  
Vol 4 (2) ◽  
pp. 10-15
Author(s):  
Suradi Wijaya Saputra
Keyword(s):  
Carapace Length ◽  
Survey Methods ◽  
Fishing Season ◽  
Central Java ◽  
Exploitation Status ◽  
Objective Research

The research of the exploitasion status of Lobster (Panullirus sp) was held on Kebumen waters Central Java. The objective research were to analysis of exploitation level and fishing season.of lobster. Samples was collected from August to September 2008, using survey methods. The study area were three TPI : TPI Pasir, TPI Argopeni and TPI Karangduwur. The results showed that Lobster caught occurred through the year, with fishing season from November to February, and peak season on December. Base on carapace length and weigh of Lobster, show that level of exploitation was indicated over-exploitation.Key word : Lobster, exploitation status, Kebumen waters

Intermolt Insemination, an Alternative Mating Strategy for the American Lobster (Homarus americanus)

1990 ◽  
Vol 47 (12) ◽  
pp. 2402-2406 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Reproductive Strategy ◽  
Carapace Length ◽  
Homarus Americanus ◽  
Mating Strategy ◽  
American Lobster ◽  
Male Aggression ◽  
Female Receptivity ◽  
Molt Stage ◽  
Alternative Mating Strategy ◽  
Ovarian Stage

American lobster (Homarus americanus) have a dual mating strategy. Although most females mate when they are newly molted, mating can occur at any molt stage if necessary, in the laboratory, virtually all uninseminated preovigerous females mate prior to spawning. Male aggression is a major factor in the success of intermolt mating and males can discriminate between immature and mature females, and between inseminated and uninseminated females. Female receptivity is affected by both ovarian stage and the presence of stored sperm, but not by molt stage. Most females become unreceptive after insemination, but their receptivity returns once the supply of stored sperm is exhausted. Intermolt mating occurs in smaller lobster that for some reason did not mate at molt, and it is an important part of the reproductive strategy of larger lobster. Lobster s[Formula: see text] carapace length frequently spawn twice without molting and often fail to store sufficient sperm to fertilize consecutive spawnings. Intermolt mating ensures these females will produce fertile second broods.

The Lobster (Homarus americanus) Fishery off Lower Argyle Southwestern Nova Scotia

1990 ◽  
Vol 47 (6) ◽  
pp. 1177-1184 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Nova Scotia ◽  
Fold Increase ◽  
Homarus Americanus ◽  
Weekly Basis ◽  
Index Numbers ◽  
Management Implications ◽  
Frequency Distributions ◽  
Fishing Season ◽  
Juvenile Abundance ◽  
Overall Mortality

Catch and effort data for the lobster (Homarus americanus) fishery of Lower Argyle, Nova Scotia, were obtained from sales slips on a weekly basis during 1978–87. Lobster size–frequency distributions were collected during at-sea sampling at the beginning and end of each fishing season. This fishery experienced a three-fold increase in landings (from 87.6 to 270 t) due to an increase in recruitment during the 10-yr study. The fishermen responded to the improved recruitment by increasing the total number of days fished per season by 41%. Overall mortality of recruited lobster (estimated from size–frequencies) rose from 55% in 1978 to 72–81% during 1985–87. During the 1987–88 fishing season, about 1 t lobster were removed per km2 of fishing grounds. Regression relationships between a prerecruit juvenile abundance index (numbers of lobster/trap haul) and the recruited yield one to two fishing seasons later were significantly correlated for 8–9 yr of data; equations predicted that lobster yields would remain high during the 1988–89 fishing season but decline in this area during 1989–90 fishing season. Management implications of forecasting recruitment yields 1–2 yr in advance and possible strategies to reduce major recruitment fluctuations in this fishery are discussed.

Growth of Tagged American Lobsters, Homarus americanus, in the Bay of Fundy

1983 ◽  
Vol 40 (10) ◽  
pp. 1667-1675 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Carapace Length ◽  
Growth Curves ◽  
Homarus Americanus ◽  
Multiple Regression Model ◽  
Growth Increment ◽  
Bay Of Fundy ◽  
Von Bertalanffy ◽  
Immature Female ◽  
Size Number ◽  
Empirical Growth

Sphyrion-tagged lobsters recaptured in the Bay of Fundy during 1977–80 yielded mean annual molt increment and molt probability data for male and female lobsters of 60–171 mm carapace length from which growth curves were calculated. In addition, a multiple regression model was used to generate growth curves from premolt size, number of molt periods lobsters were exposed to, and growth increment data for 850 tagged lobsters at liberty for 1–5 yr. Von Bertalanffy parameters were calculated from these empirical growth curves, which suggest that lobsters take 20–35 yr from time of hatching to reach 200 mm carapace length in the Bay of Fundy. Analysis of pleopods indicated that the majority of lobsters molt during August–October each year. Growth per molt of immature (60–94 mm carapace length) and mature (95–170 mm carapace length) male and immature female lobsters was arithmetic (regression slope 1.04) but was regressive for mature females (slope 0.95). Mature lobsters molted less frequently than immature lobsters, but mature males grew more rapidly than mature females. Most mature females in the Bay of Fundy are on a 2-yr molt–reproductive cycle. About 20% of ovigerous females recaptured within 2 yr after release had extruded eggs a second time without molting, confirming that multiple egg extrusions between molts do occur naturally.

The catchability of large American lobsters (Homarus americanus) from diving and trapping studies off Grand Manan Island, Canadian Maritimes

2006 ◽  
Vol 63 (9) ◽  
pp. 1925-1933 ◽  
Author(s):  
M J Tremblay ◽  
S J Smith ◽  
D A Robichaud ◽  
P Lawton
Keyword(s):  
Generalized Linear Models ◽  
Carapace Length ◽  
Linear Models ◽  
Size Range ◽  
Late Summer ◽  
Homarus Americanus ◽  
Agonistic Interactions ◽  
Size Groups ◽  
Early Fall ◽  
Catch Rates

Catchability (q) in traps was estimated for American lobsters (Homarus americanus) in Flagg Cove, off Grand Manan Island (New Brunswick, Canada), where large females (>100 mm carapace length (CL)) aggregate in late summer and early fall. In 2001 and 2002, diver surveys were used to estimate lobster density, and traps were then deployed to obtain catch rates. Bayesian generalized linear models were fit to the densities of different size groups (81–100, 101–130, 131–160, and >160 mm CL) of ovigerous females, non-ovigerous females, and males. Catchability was strongly affected by year. Differences in q due to sex and size for ovigerous females, non-ovigerous females, and males were apparent but were not consistent between years. Size was not an important factor for the catchability of lobsters between 81 and 160 mm CL. In comparison with lobsters of a similar size in other areas, Flagg Cove lobsters in the size range of 81–100 mm CL were less catchable. We hypothesize that this resulted from the high densities and larger sizes of lobsters in Flagg Cove, which likely lead to increased agonistic interactions and reduced entry of lobsters into traps.

scholarly journals Using temperature-dependent embryonic growth models to predict time of hatch of American lobster (Homarus americanus) in nature

2016 ◽  
Vol 73 (10) ◽  
pp. 1483-1492 ◽  
Author(s):  
Erin Miller ◽  
Marthe Larsen Haarr ◽  
Rémy Rochette
Keyword(s):  
Growth Models ◽  
Homarus Americanus ◽  
American Lobster ◽  
Temperature Dependent ◽  
Fishing Season ◽  
Dependent Development ◽  
Eye Size ◽  
Gravid Females ◽  
Frequent Sampling ◽  
Hatch Period

Hatch time of American lobster (Homarus americanus) varies between years and regions, which affects temperature experienced by the developing larvae and hence the time and distance these drift before settling. Hatch time can be assessed by working with fishermen and inspecting the brood of gravid females caught in their traps. However, this would require frequent sampling as the hatch period is protracted (≈7–12 weeks) and would require dedicated sampling in many regions where hatching occurs outside of the fishing season. To address these limitations, we tested the accuracy with which hatch time can be predicted by taking egg samples during the fishing season and estimating embryo development using embryonic eye size (Perkins eye index) and lab-derived, temperature-dependent development functions. Using a linear development function and observed variability in Perkins eye index at hatch, we successfully predicted 100% of the observed 50-day hatch period, and 96% of predicted hatch dates fell within this period. Our results suggest that samples can be obtained in collaboration with fishermen to predict the timing and progression of hatch of American lobster.

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