First Records of Mated Female Loligo Gahi (Cephalopoda: Loliginidae) in the Falkland Islands

This communication presents the first records of mated female Loligo gahi in Falkland Island waters. In October 1993 fully mature mated female L. gahi were identified in samples taken from the commercial fishery in waters east of Lively Island, East Falkland, at depths of 145–174 m. Spermatophores were found in both the mantle cavity and buccal sites of deposition. These records, combined with past records of spent females, suggest spawning periods in late October/early November and April/May. These concur with two of the three periods of spawning suggested from previous studies of juvenile and adult L. gahi.

Download Full-text

Reproductive biology, sexual dimorphism, and population structure of the deep sea hydrothermal vent scale-worm, Branchipolynoe seepensis (Polychaeta: Polynoidae)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315499001563 ◽

2000 ◽

Vol 80 (1) ◽

pp. 55-68 ◽

Cited By ~ 32

Author(s):

D. Jollivet ◽

A. Empis ◽

M.C. Baker ◽

S. Hourdez ◽

T. Comtet ◽

...

Keyword(s):

Sexual Dimorphism ◽

Deep Sea ◽

Hydrothermal Vents ◽

Reproductive Tract ◽

Mantle Cavity ◽

Differential Mortality ◽

Internal Fertilization ◽

Wide Range ◽

Males And Females ◽

Spawning Periods

The polychaete family Polynoidae (scale-worms) is well-represented at deep sea hydrothermal vents. Most species are free-living in a wide range of habitats: from high-temperature hydrothermal `chimney' walls to diffuse venting areas. Conversely, species of the genus Branchipolynoe live inside the mantle cavity of vent and seep mytilids. Specimens, morphologically close to Branchipolynoe seepensis, have been reported from all the known vent areas on the Mid-Atlantic Ridge (MAR), with varying infestation rates (0–6 individuals per host). Reproductive tract, gametogenesis and population structures were examined for specimens from the Lucky Strike vent field (MAR) in order to test whether this species displays dwarf males, protandric hermaphroditism or differential mortality between males and females. Observations of histological sections reveal the presence of fully developed ovaries in females which originate ventrally in segments 7–9 and of an unusual genital tract in which both sperm and mature oocytes are stored. Oogenesis is intraovarian and quasi-continuous. The vitellogenic oocytes are only free in the coelom at their terminal growing stage and are then transferred into an ovisac through spermathecae. The species displays an external sexual dimorphism in the number of genital papillae and the shape of the pygidial appendages. Sex ratios showed significant deviations from a 1:1 expected ratio, in favour of females. The modal decompositions of size–frequency histograms show the occurrence of three modes in females and only two modes in males, indicating discrete breeding periods. The two first modes were not significantly different between males and females. These results indicate that B. seepensis forms heterosexual pairs and uses internal fertilization to reproduce during discrete spawning periods. Differential mortality between males and females is likely to shape size-histograms as observed by preventing males from reaching the female proportions. Such an observation could be a result of either cannibalism on larger males, small sizes facilitating the male escape, or natural predation when males move from one bivalve to another to breed.

Download Full-text

Assessing the stock status of holobenthic octopus fisheries: is catch per unit effort sufficient?

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn224 ◽

2009 ◽

Vol 66 (3) ◽

pp. 478-487 ◽

Cited By ~ 13

Author(s):

Stephen C. Leporati ◽

Philippe E. Ziegler ◽

Jayson M. Semmens

Keyword(s):

Egg Production ◽

Biological Information ◽

Life History Strategies ◽

Sufficient Information ◽

Commercial Fishery ◽

Catch Per Unit Effort ◽

Stock Status ◽

Unit Effort ◽

The Status ◽

Spawning Periods

Abstract Leporati, S. C., Ziegler, P. E., and Semmens, J. M. 2009. Assessing the stock status of holobenthic octopus fisheries: is catch per unit effort sufficient? – ICES Journal of Marine Science, 66: 478–487. Holobenthic and merobenthic octopus fisheries are commonly treated as biological equivalents, regardless of their contrasting life-history strategies. This is the consequence of a lack of species identification and relevant biological information for many species, which has led to a reliance on catch per unit effort (cpue) data for stock status assessments. Using the commercial Octopus pallidus fishery in southeast Australian waters as a case study, the reliability of commercial cpue data as an indicator of stock status for holobenthic octopus fisheries was assessed. To achieve this, cpue and biological information from a fixed position experimental research line were investigated for consistency in stock status patterns and compared with commercial fishery cpue trends. Research line results revealed that cpue could remain stable regardless of size-selective fishing mortality potentially impacting recruitment. The cpue in the commercial fishery was very seasonal and dominated by females during autumn, when both cpue and spawning periods peaked, so increasing the potential for negative fishery impacts on egg production. The inability of cpue to account for the effects of continual fishing pressure on recruitment or seasonal changes in sex-specific catchability, however, indicates that cpue alone cannot provide sufficient information on the status of a holobenthic octopus fishery.

Download Full-text

Biology of the skates Bathyraja brachyurops and B. griseocauda in waters around the Falkland Islands, Southwest Atlantic

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn015 ◽

2008 ◽

Vol 65 (4) ◽

pp. 560-570 ◽

Cited By ~ 12

Author(s):

Alexander I. Arkhipkin ◽

Nina Baumgartner ◽

Paul Brickle ◽

Vladimir V. Laptikhovsky ◽

Joost H. W. Pompert ◽

...

Keyword(s):

Shelf Break ◽

Falkland Islands ◽

Marine Science ◽

Commercial Fishery ◽

Southwest Atlantic ◽

Spawning Grounds ◽

Male And Female ◽

Vertebral Centra ◽

Patagonian Shelf ◽

Growth Increments

Abstract Arkhipkin, A. I., Baumgartner, N., Brickle, P., Laptikhovsky, V. V., Pompert, J. H. W., and Shcherbich, Z. N. 2008. Biology of the skates Bathyraja brachyurops and B. griseocauda in waters around the Falkland Islands, Southwest Atlantic. – ICES Journal of Marine Science, 65: 560–570. The distributions and length compositions of two large, abundant skates, broadnose skate Bathyraja brachyurops and grey-tail skate B. griseocauda, were studied using an extensive dataset (∼48 000 skates) collected from the commercial fishery and research cruises on the southeastern Patagonian Shelf around the Falkland Islands between 1992 and 2006. Bathyraja brachyurops mostly inhabit the shelf at depths shallower than 250 m, whereas B. griseocauda are found deeper (>250 m), off the shelf break and slope. Small individuals of both species are most segregated spatially. Growth increments on caudal thorns and vertebral centra revealed that B. brachyurops grow slower and have a shorter lifespan, attaining a maximum total length of 125 cm at 20 years, compared with B. griseocauda (∼150 cm at 28 years). Maturity is attained at 8–10 years for male and female B. brachyurops, and at 15 and 17 years for B. griseocauda, respectively. Spawning takes place on spatially segregated spawning grounds, B. brachyurops reproducing above the shelf break, and B. griseocauda just below the shelf break throughout the year, with a smaller proportion of females of both species laying eggs in winter.

Download Full-text

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168621 ◽

1994 ◽

Vol 52 ◽

pp. 178-179

Author(s):

Nancy R. Wallace ◽

Craig C. Freudenrich ◽

Karl Wilbur ◽

Peter Ingram ◽

Ann LeFurgey

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Time Course ◽

Vertical Plane ◽

Mantle Cavity ◽

Qualitative Assessment ◽

Calcium Deposition ◽

Free Swimming ◽

Freeze Dried ◽

Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Download Full-text

Central forebrain Fos responses to familiar male odours are attenuated in recently mated female mice

European Journal of Neuroscience ◽

10.1046/j.1460-9568.2001.01382.x ◽

2001 ◽

Vol 13 (2) ◽

pp. 389-399 ◽

Cited By ~ 1

Author(s):

Heather A. Halem ◽

James A. Cherry ◽

Michael J. Baum

Keyword(s):

Female Mice ◽

Mated Female

Download Full-text

Bartholomew Sulivan and early watercolours of Falkland Islands vegetation in the National Botanic Gardens, Dublin

Archives of Natural History ◽

10.3366/anh.1986.13.2.155 ◽

1986 ◽

Vol 13 (2) ◽

pp. 155-163

Author(s):

D. M. MOORE ◽

M. J. P. SCANNELL

Keyword(s):

Falkland Islands ◽

Herbarium Specimens ◽

Botanic Gardens

Three hitherto undocumented watercolours in the possession of the National Botanic Gardens, Dublin, are found to depict botanically interesting views of Falkland Islands' vegetation and an historically important painting of Port Louis about 1842, when it was the capital of the archipelago. From the evidence available it seems clear that these paintings were prepared by either Bartholomew J. Sulivan or his wife during a surveying voyage to the Falkland Islands in 1842–43, when he commanded the brig Philomel. Some associated herbarium specimens seem to have been collected by B. J. Sulivan during 1838 when he visited the Falkland Islands as Lieutenant aboard the surveying ketch Arrow.

Download Full-text