World Congress of Malacology Antwerp ... - Unitas Malacologica

minimal or no branching are more primitive species, whereas animals with vastly branched digestive
tissue are highly evolved for maintaining algal symbionts. In this study, two new species of
Phyllodesmium from the Philippine Islands and Japan are described. Both species have no digestive
gland branching, and do not harbor symbiotic zooxanthellae. A preliminary examination of the
Phyllodesmium phylogeny suggests that these species are basal, further indicating that symbiosis is a
derived trait in this group.
Vertigo geyeri in a lowland Irish fen - asking the right questions and getting the answers
Moorkens, Evelyn A.
53, Charleville Square, Rathfarnham, Dublin 14, Republic of Ireland,
Email: emoorkens@eircom.net
Vertigo geyeri has protected status under Annex II of the European Union Habitats and Species
Directive. Member states with populations of this species must maintain Special Areas of
Conservation in favourable conservation status. This has presented a challenge to national authorities
charged with its protection.
This paper outlines ten years of studies in a lowland fen in the Republic of Ireland. A number of
methodologies and results are outlined; each designed in order to answer specific questions. Repeated
surveys ranged from general fen survey (200 hectares) to annual surveys of 57 separate quadrats
(1m²) to monthly assessments of 2,000 quadrats (5cm²), including methodologies of destructive
sampling and non-destructive sampling.
The fen used in this ten year study was impacted by dewatering of the aquifer driving its
hydrogeology, so baseline and post-impact results are presented from the various methodologies
used.
General walk-over surveys with non-destructive sampling were found to be useful in locating
important patches of habitat for more intensive study. Annual surveys at the medium (1m²) scale
provided useful data regarding the mobility of V. geyeri, and the benefits and shortcomings of
utilizing wetness indices based on a wide range of molluscan species. In general, wetness indices
were poor at measuring small scale changes, but good at highlighting gross changes. Intensive nondestructive
survey contributed to a larger hydrogeological model that was able to define the microhabitat
requirements of this tiny species. Monthly destructive sampling on a wider scale was able to
provide useful measurement of change and has been used in examining the effects of temporary
mitigation measures at the site.
The combined work over the last ten years has been used in the design of a monitoring survey
methodology for all areas protected for V. geyeri under European law in the Republic of Ireland.
Reproductive cycle of the giant clam Panopea generosa at Magdalena Bay, South Baja
California, Mexico
Morales Gómez, Ana Adalia 1 ; Salgado Ugarte, Isaías H. 1 ; Uría Galicia, Esther 2 ; Gluyas Millán,
M. Georgina 3 ; Gómez Márquez, José Luis 1
1. Laboratorio de Biometría y Biología Pesquera y Laboratorio de Limnología, Facultad de Estudios
Superiores Zaragoza, UNAM, Batalla 5 de mayo s/n Esq, Fuerte de Loreto, Col. Ejército de Oriente,
C.P 09230, Mexico,
Email: adalia2@yahoo.com.mx.
2. Laboratorio de Histología. Escuela Nacional de Ciencias Biológicas-IPN, Prolongación de Carpio
y Plan de Ayala s/n. Col, Casco de Santo Tomas, C.11340, Mexico,
3. Centro Regional de Investigación Pesquera La Paz-INP-SAGARPA., Km 1 carretera a Pichilingue,
La Paz, B.C.S., 23020 Mexico
In the Mexican western coast a high percentage of the demand for fishing resources is concentrated in
the bivalve mollusks. The giant clam Panopea generosa is considered a potentially exploitable
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