The influence of age on reproductive success and diet in Australasian gannets (Morus Serrator) breeding at Pope's Eye, Port Phillip Bay, Victoria

The influence of age on reproductive success and diet was examined in ‘old’ (experienced; 12 years and older) and ‘young’ (5–8 years of age) Australasian gannets (Morus serrator) breeding at Pope’s Eye, Port Phillip Bay, Victoria during the 2002–2003 breeding period. Although food availability, as indicated by commercial fish catches, throughout this breeding period was low, there were no significant differences in breeding success or chick growth between groups. Nevertheless, old birds tended to have higher reproductive success, replacing more lost eggs and fledging chicks of a greater mass. However, old birds also laid more eggs that failed to hatch. Five fish species, including jack mackerel (Trachurus declivis), barracouta (Thyrsites atun), redbait (Emmelichthys nitidus), anchovy (Engraulis australis) and red mullet (Upeneichthys vlamingii), were important in the gannet diet during this breeding period. There were no significant differences in dietary parameters, including range of species and size of prey, between old and young gannets, nor were there any differences between those of the chicks and their parents, suggesting that adults do not forage selectively for their chicks. This study showed that even during a period of presumed low food availability, when experienced (older) birds might be expected to have enhanced success, the differences between these and less experienced (younger) birds may not be apparent.

Deus caritas est : more than papal lyricism

Deus caritas est: et qui manet in caritate, in Deo manet, et Deus in eo.

God is love, and he who abides in love abides in God, and God abides in him (1John 4:16b).

Many believe in or claim that they believe and hold fast to Catholic doctrine on such questions as social authority... on the relations between Church and State, religion and country ... on the rights of the Holy See and the prerogatives of the Roman Pontiff and the Episcopate, on the social rights of Jesus Christ, Who is the Creator, Redeemer, and Lord not only of individuals but of nations. In spite of these protestations, they speak, write, and, what is more, act as if it were not necessary any longer to follow, or that they did not remain still in full force, the teachings and solemn pronouncements which may be found in so many documents of the Holy See ... (Pope Pius XI, 1922). It is a mistake to state that political, economic, and social liberation coincide with salvation in Jesus Christ; that the regnum Dei is identified with the regnum hominis (Pope John Paul I, 1978).

Microsatellites revealed no genetic differentiation between hatchery and contemporary wild populations of striped catfish, Pangasianodon hypophthalmus (Sauvage 1878) in Vietnam

Aquaculture of the striped catfish, Pangasianodon hypophthalmus (Sauvage 1878), in Vietnam has become one of the fastest growing primary food production sectors in the world. Although a demand on quantity of fingerlings is currently reached, it is likely that the long term quality of the stocks may be uncertain due to lacking of genetic broodstock management measures. The present study employed five microsatellite loci to investigate levels of genetic variation of the stripped catfish of the current wild stocks as well as of the selected hatcheries in Vietnam. The study included four hatchery populations and two wild populations spawned in 2005 in the Mekong and Bassac Rivers, and one wild population (spawned in 2006) in the Bassac River. The results showed no genetic differentiation among populations as revealed by F_ST and a model-based clustering method. AMOVA also showed no genetic differentiation between pooled wild and pooled hatchery populations while variation within groups was significant. Genetic variation of wild (mean number of alleles per locus, A = 4.80–6.20; allelic richness, A_r = 4.54–5.06; mean effective number of alleles per locus, A_e = 2.86–3.20; observed heterozygosity, H_o = 0.62–0.65; expected heterozygosity, H_e = 0.62–0.64) and hatchery populations (A = 4.60–5.20; A^_r = 4.10–4.83; A_e = 2.80–3.11; H_o = 0.61–0.66; H_e = 0.61–0.64) were not statistically different. There were no evidences for recent genetic bottleneck in all populations. Therefore it is implied that the hatchery stocks of striped catfish in Vietnam were founded from sufficient numbers of brooders and current population size is large. The domestication process is in an early stage.

Patterns of use and exchange of genetic resources of the striped catfish Pangasianodon hypophthalmus (Sauvage 1878)

The present paper reviews the use and exchange of genetic resources of the migratory freshwater fish Pangasianodon hypophthalmus (Sauvage 1878) (the striped or sutchi catfish). This species is naturally distributed in the Mekong River and Chao Phraya River basins, and is cultured in several countries, but current production occurs predominantly in the Mekong Delta, Vietnam. Catfish aquaculture in Vietnam has evolved from extensive systems using wild-caught seed to an intensified farming system that is entirely dependent on hatchery-produced seed. Genetic improvement programmes on catfish have started in Vietnam, but are still in their infancy. Genetic studies have revealed several subpopulations of the species. Apart from selective breeding and the production of hybrids with closely related species, no other technologies have been applied to improve the performance of catfish. The use and exchange of P. hypophthalmus genetic resources have brought benefits to rural communities. Aquaculture development of catfish has evolved from being seen as an exploitation of natural resources to an activity that can reduce pressure on wild fish populations. Management of aquaculture stocks need to be rationalised to minimise the potential impacts it might cause to wild populations.