scholarly journals Vulnerability of male spider crab Maja brachydactyla (Brachyura: Majidae) to a pot fishery in south-west Ireland

2009 ◽  
Vol 89 (7) ◽  
pp. 1353-1366 ◽  
Author(s):  
Edward Fahy ◽  
Jim Carroll
Keyword(s):  
Carapace Length ◽  
Fishing Effort ◽  
Spider Crab ◽  
Mark Recapture ◽  
Fishing Season ◽  
South West ◽  
Fishing Capacity ◽  
One Year

The Magharees fishery (Brandon and Tralee Bays in south-west Ireland) is 495 km2 in extent, the majority of this area ≤20 m in depth. Since 1981 it has been occupied by a directed spider crab fishery yielding in some years all of the national catch of Maja brachydactyla. Maximum recorded landings were 336 t in 1999 and effort has numbered up to 10,000 pots annually. Increasing fishing capacity and declining opportunities have accentuated fishing effort on spider crab. This paper describes a catch census undertaken in the fishing season of March to August inclusive, 2000–2007 and a mark–recapture experiment, 2005–2007. A method of ageing the adult moult by attributing a chronology to the rate of erosion of the claw on the dactyl is introduced. Males migrated longer distances, moved into the fishery on a wider trajectory and demonstrated greater wear on the claw than females. Recapture rate of males was twice that of females. The conduct of the fishery changed in its 26 years in existence. Landings became more concentrated in the earlier months of the year and the recent summer fishery was characterized by fewer male captures. Larger males were quickly removed and none >140 mm carapace length survived in the fishery longer than one year.

scholarly journals The relative weight of traditions, economics, and catch plans in New Zealand fleet dynamics

2009 ◽  
Vol 66 (2) ◽  
pp. 291-311 ◽  
Author(s):  
Paul Marchal ◽  
Philippe Lallemand ◽  
Kevin Stokes
Keyword(s):  
New Zealand ◽  
Relative Weight ◽  
Fishing Effort ◽  
Expected Profit ◽  
Nested Logit ◽  
Individual Transferable Quota ◽  
Management Regime ◽  
One Year ◽  
Fleet Dynamics ◽  
Statistical Area

We investigate the relative weights of catch plans, expected profit, and traditions in fishers’ decision-making for five New Zealand fleets subject to an individual transferable quota (ITQ) management regime. Métiers were defined for these fleets as a combination of gears, management units, and a targeting index (either target species or statistical area). A nested logit random utility model was used to model the métier allocation of fishing effort in relation to catch plans, expected profit, and past fishing allocations. This study showed that traditions and catch plans appeared to be important determinants of fishers’ behavior for these New Zealand fleets. The model developed in this study fitted the data generally well and was also able to predict, in most cases, future effort allocation both one month and one year ahead.

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.

Biennial Reproductive Cycle of Blue King Crab, Paralithodes platypus, at the Pribilof Island, Alaska and Comparison to a Congener, P. camtschatica

1989 ◽  
Vol 46 (6) ◽  
pp. 932-940 ◽  
Author(s):  
Gregory C. Jensen ◽  
David A. Armstrong
Keyword(s):  
Carapace Length ◽  
Reproductive Output ◽  
Size Range ◽  
Egg Mass ◽  
King Crab ◽  
Pribilof Island ◽  
Blue King Crab ◽  
Paralithodes Platypus ◽  
One Year ◽  
Reproductive Events

Pribilof Island blue king crab (BKC; Paralithodes platypus) were sampled by beam trawl in May and August of 1983 and April 1984 to determine timing of reproductive events. Biennial reproduction was found to be the result of slow ovarian growth in large, muciparous females, while smaller primiparous females are often able to spawn in two consecutive years. Mating and egg extrusion occur in late March to early May and eggs hatch in mid-April of the following year, consequently, the embryonic period and rate of development is approximately 12 mo, similar to that of its congener the red king crab (RKC; P. camtschatica). Comparison of the reproductive output of the two species revealed that despite the 2 yr ovarian cycle, BKC only produce 20–30% more dry egg mass at any carapace length than do RKC, a substantially smaller difference than previously calculated. One year after molt, females of both species are not significantly different in dry body weight over a size range of 100–140 mm carapace length, but RKC have produced about three times more dry ovarian weight than BKC of comparable size, suggesting that biennial reproduction in BKC may be the result of energetic limitations.

Shark fisheries in Argentina

1998 ◽  
Vol 49 (7) ◽  
pp. 601 ◽  
Author(s):  
Gustavo E. Chiaramonte
Keyword(s):  
Fishing Effort ◽  
Population Trends ◽  
The South ◽  
Gill Nets ◽  
Argentine Sea ◽  
Commercial Importance ◽  
South West ◽  
Gill Net ◽  
Galeorhinus Galeus ◽  
Mustelus Schmitti

In the Argentine Sea there are about 35 species of sharks. Three species are subjected to directed fishing: the smoothhound Mustelus schmitti, the school shark Galeorhinus galeus and the copper shark Carcharhinus brachyurus. Other species of elasmobranchs with commercial importance are the angel shark Squatina spp. and several species of skates and rays. The rise in chondrichthyan declared landings registered from 1988 to 1996 is due to the increase in landings of smoothhound and rays. The most important directed shark fishery in the South-West Atlantic is the Necochea gill-net fishery for school shark, which is carried out by the coastal fleet; details are given of the ships and the gill-nets used in this area. The length frequencies of the catches by gill-nets are presented for the school shark; fishing effort (length (km) of net in the water per ship per day) and CPUE (number of sharks per fishing effort) were found not to be good indicators of population trends in the school shark fishery. Resumen. En el Mar Argentino se han registrado 35 especies de tiburones. Tres de estas especies están sometidas a una pesca dirigida; el gatuzo, Mustelus schmitti, el cazón, tiburón vitamínico o trompa de cristal, Galeorhinus galeus y la bacota, Carcharhinus brachyurus. Otras especies de elasmobranquios de importancia comercial son el pez ángel Squatina spp. y algunas especies de rayas. El incremento en los desembarcos de condríctios declarados a las autoridades pesqueras entre 1988 y 1996 es debido principalmente al incremento del desembarco de gatuzo y rayas. La pesquería dirigida a tiburón más importante en el Atlántico Sudoccidental es la pesquería costera de enmalle de Necochea para el cazón. Se describen el largo de las embarcaciones y las redes utilizadas en el área (la medida de malla, el calado y la operación del arte de pesca). Se presenta la frecuencia del largo total de las capturas de cazón en redes de enmalle. Se halló para la pesquería del cazón que el esfuerzo pesquero (estimado como km de red en el agua por embarcación por día) y la CPUE (estimada como tiburones/esfuerzo de pesca) no son buenos indicadores de la tendencia en la abundancia poblacional.

Restructuring the Tasmanian rock-lobster fishery - the effect of two years of management under individual transferable quotas

2001 ◽  
Vol 52 (8) ◽  
pp. 1641 ◽  
Author(s):  
Wes Ford ◽  
Wes Ford
Keyword(s):  
Egg Production ◽  
Fishing Effort ◽  
Rock Lobster ◽  
Quota System ◽  
Individual Transferable Quotas ◽  
Fishing Vessels ◽  
Early Results ◽  
Lobster Fishery ◽  
Quota Management ◽  
One Year

Individual transferable quotas were successfully introduced into the Tasmanian rock-lobster fishery in 1998. In the two years since, significant industry restructuring has occurred. The move to quota management was intended to meet two key objectives: to reduce the catch to a sustainable level, allowing the stock to rebuild, and to provide a mechanism whereby the industry could achieve economic sustainability. The quota system has achieved early results on both the sustainability and restructuring objectives and is now well accepted and supported by the vast majority of fishers and licence holders. Its effect has been to reduce fishing effort by 29% and number of fishing vessels by 23%, and the reduction in catch has resulted in a 6% increase in the estimated biomass and substantial increases in egg production after one year. Fishers now spend fewer days at sea, and catch rates are improving. These changes are reducing fishing costs, which in time should increase profitability. Social costs of introducing quotas are that fewer fishers are employed on vessels and that fishers now find it harder and more expensive to lease a fishing licence. These costs must be factored into any assessment of the industry.

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 Age, growth, mortality and yield per recruit of the dourado Salminus brasiliensis, Corumbá Reservoir, Goiás State, Brazil

2009 ◽  
Vol 7 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Claudenice Dei Tos ◽  
Luiz Carlos Gomes ◽  
Angelo Antônio Agostinho ◽  
Rosana Paulo Batista
Keyword(s):  
Mortality Rate ◽  
Total Mortality ◽  
Fishing Effort ◽  
Average Weight ◽  
Migratory Species ◽  
Reservoir Impoundment ◽  
Annual Total ◽  
One Year ◽  
Yield Per Recruit ◽  
Salminus Brasiliensis

In order to evaluate the fate of the migratory species dourado Salminus brasiliensis in the first years of impoundment in Corumbá Reservoir we estimated age, growth, mortality and yield per recruit. Samplings were carried out monthly in Corumbá Reservoir and its main tributaries (Goiás State) from March 1998 to February 1999 using gillnets. After one year of impoundment, age was estimated from scales and the maximum number of rings was six for males and five for females. Rings are formed annually in May and June. The asymptotic length and growth rate for males and females were 37.1 cm and 0.77 and 56.6 cm and 0.52, respectively. A dominance of juveniles was verified in the reservoir and its tributaries. The instantaneous total mortality rate (Z) was 1.59 and the annual total mortality rate (A) was 79.6%. The highest yield per recruit (1200g) and the highest average weight (1900g) were obtained in simulations with low values of fishing (F) and natural (M) mortalities. Based on the above information we describe the Corumbá Reservoir impoundment has influenced the growth of the dourado. As regards this study, we recommend that the fishing effort not be applied during the trophic upsurge period and that the monitoring of the dourado assemblage continue. Fishery programs management for this species should be carried out with subsequent monitoring involving efficient communication, realistic practices and involvement of fisher organizations.

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

Problems and Perspectives Regarding Recruitment of Spiny Lobsters, Panulirus argus, to the South Florida Fishery

1986 ◽  
Vol 43 (11) ◽  
pp. 2099-2106 ◽  
Author(s):  
William G. Lyons
Keyword(s):  
Carapace Length ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
International Management ◽  
South Florida ◽  
Panulirus Argus ◽  
Minimum Size ◽  
Juvenile Growth ◽  
Larval Recruitment ◽  
Yield Per Recruit

Inappropriate minimum size, illegal harvest, fishery-induced juvenile growth retardation and mortality, and excessive effort have reduced reproductive contributions and depressed yield-per-recruit in the overcapitalized south Florida spiny lobster (Panulirus argus) fishery. Measures recommended to improve yield-per-recruit are as follows: increase minimum legal size to 85–90 mm carapace length; require escape gaps in traps; eliminate possession of sublegal lobsters aboard vessels; prohibit harvest in nurseries; reduce fishing effort; improve enforcement of fishery regulations; and initiate programs to educate fishermen regarding impacts of fishery practices. International management is recommended to assure larval recruitment among Pan-Caribbean stocks.

Characterization of a population of the Harlequin crab, Lissocarcinus orbicularis Dana, 1852, an obligate symbiont of holothuroids, in Toliara bay (Madagascar)*

Zoosymposia ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. 177-184 ◽  
Author(s):  
GUILLAUME CAULIER ◽  
ERIC PARMENTIER ◽  
GILLES LEPOINT ◽  
FLEUR VAN NEDERVELDE ◽  
IGOR EECKHAUT
Keyword(s):  
Sexual Dimorphism ◽  
Mating System ◽  
Carapace Length ◽  
Barrier Reef ◽  
South West ◽  
Obligate Symbiont ◽  
Adult Crab ◽  
Gravid Females

Harlequin crabs, Lissocarcinus orbicularis, are commensals found on the integument and in the buccal/cloacal cavity of several species of holothuroids. The population of these crabs was investigated on holothuroids of the barrier reef of Toliara (South-West of Madagascar) from 2002 to 2008. Seventeen holothuroid species were observed and eight were crab hosts. There is generally one adult crab or a heterosexual pair per infested holothuroid but up to ten juveniles were recorded on a Thelenota ananas. Carapace length of the observed L. orbicularis was from 0.3 to 1.4 cm from the tip of the rostrum to the end of the cephalothorax, with a mean length of 0.85 cm. L. orbicularis is characterized by a weak sexual dimorphism (females are bigger than males) and the presence of pereiopods morphologically adapted to fixation on the host integument. Gravid females were observed at each month of the survey indicating that the crab reproduces all the year. Considering our results and personal observations, we also discuss the monogamy mating system of the Harlequin crab.

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