Genetic variability and relationships among geographically widely separated populations of Petitia amphophthalma (Polychaeta: Syllidae). Results from RAPD-PCR investigations

An analysis of the population genetics of the meiofaunal polychaete Petitia amphophthalma Siewing, 1956, in which the RAPD-PCR method was applied to 103 individuals from eight populations, some of them very far apart (Atlantic: Florida, Tenerife, France; Mediterranean: two Greek islands, Tunisia; Red Sea: Egypt), gave closely reproducible results. In the band patterns produced with 13 decamer primers, a total of 195 genetic characters was detected. The data were evaluated by a number of methods, including the cluster programs UPGMA, WPGMA and neighbour-joining. The detected genetic distances between the populations vary between 58.9 and 66.6, but 97% of the genetic characters, although polymorphic, are found in at least two populations and usually in all the others as well. Phenograms of the analyses find four population clusters [Florida, France (Atlantic), the Mediterranean and Tenerife]. They are, however, not completely congruent and show low bootstrap values at the junction points of the clusters (with the exception of the Tenerife cluster). Mediterranean P. amphophthalma form a cohesive population, although within it the genetic distances are graded in parallel with the geographic distances between the sites. The colonization of Tenerife, an island of relatively recent volcanic origin, can be taken as evidence that this meiofaunal species can become dispersed not only along coastlines but also across expanses of open water. However, the severely restricted variability of these populations implies that in this case a founder effect has operated, and that transport over open water is not a routine event but extremely rare. The absence of the species on the Australian coast and, for instance, on the Galapagos Islands indicates that there has been no continuous gene flow across the oceans. The idea that all the populations investigated belong to one cosmopolitan species is discussed. Received: 17 October 1997 / Accepted: 15 April 1998     

Integrating regional perceptions into climate change adaptation: a transdisciplinary case study from Germany’s North Sea Coast

Coastal protection strategies increasingly have to take into account the effects of climate change. At present, engineering and natural science models that assess the impact of global climatic transformations on regional coastal zones and their protection structures remain rather detached from the knowledge and insights of regional practitioners. The main thesis of this contribution, using a case study from the North Sea Coast of Germany, is that innovative coastal protection requires not only interdisciplinary research but transdisciplinary collaboration in order to develop a viable adaptation strategy. The investigation of the social dimension of climate change and coastal protection strategies, using qualitative interviews with organized regional stakeholders, climate researchers and coastal engineers, as well as a representative public survey, contributes to a comprehensive understanding of regional perceptions with respect to climate change and coastal protection.     

Results of the UNDP (SF)/FAO regional fisheries survey in West Africa. Report No. 1. Deep-scattering Sardinella aurita off Mauritania

Scattering layers beyond the Continental Shelf, in deep water, were often observed during cruises with the charter vessel of the Regional Fisheries Survey in West Africa. The layers were located at depths of 100 to 350 m during daytime; at night, they generally ascended to the surface. They consisted mainly of myctophids and small squids. In this report, results of first observations on deep-scattering layers of Sardinella aurita (Cuv. et Val.) are given. The layers occurred off Mauritania during the months of hydrological transition, characterized by low water-temperatures. In these months, S. aurita were rarely caught over the shelf. Apparently, they migrate north and south in deep water, and were not detected by commercial vessels. The environmental conditions and the difficulties for the industrial fishery during this transitional period are briefly described. the temporal and spatial occurrence of deep-scattering S. aurita is given, and diurnal vertical migrations are shown, together with examples of echo records. Results of fishing operations made in the layer, and some biological observations on S. aurita are presented.     

An association between fetal abdominal wall defects and elevated levels of human chorionic gonadotropin in mid-trimester

We analysed maternal serum human chorionic gonadotropin (hCG) in 16 pregnancies with fetal abdominal wall defects previously identified prenatally by elevated maternal serum alpha-fetoprotein (AFP) or at birth. The AFP levels had a mean of 6·38 MOM (range 0·34–15·65), as expected with these defects. The hCG levels had a mean of 1·82 MOM (range 0·23–4·11). The hCG levels in five pregnancies (31·25 per cent) were above 2·30 MOM. Elevated levels of hCG may be associated with fetal abdominal wall defects.