A novel system for intensive Diadema antillarum propagation as a step towards population enhancement

The long-spined sea urchin Diadema antillarum was once an abundant reef grazing herbivore throughout the Caribbean. During the early 1980s, D. antillarum populations were reduced by > 93% due to an undescribed disease. This event resulted in a lack of functional reef herbivory and contributed to ongoing ecological shifts from hard coral towards macroalgae dominated reefs. Limited natural recovery has increased interest in a range of strategies for augmenting herbivory. An area of focus has been developing scalable ex situ methods for rearing D. antillarum from gametes. The ultimate use of such a tool would be exploring hatchery origin restocking strategies. Intensive ex situ aquaculture is a potentially viable, yet difficult, method for producing D. antillarum at scales necessary to facilitate restocking. Here we describe a purpose-built, novel recirculating aquaculture system and the broodstock management and larval culture process that has produced multiple D. antillarum cohorts, and which has the potential for practical application in a dedicated hatchery setting. Adult animals held in captivity can be induced to spawn year-round, with some evidence for annual and lunar periodicity. Fecundity and fertilization rates are both consistently very high, yet challenges persist in both late stage larval development and early post-settlement survival. Initial success was realized with production of 100 juvenile D. antillarum from ~ 1200 competent larvae. While the system we describe requires a significant level of investment and technical expertise, this work advances D. antillarum culture efforts in potential future hatchery settings and improves the viability of scalable ex situ production for population enhancement.

Phylogenetic characteristics of selected European huchen (Hucho hucho L.) broodstocks – implication for broodstock management

European huchen (Hucho hucho) is a representative of large and rare migratory salmonid fish, which has become endangered due to extensive anthropogenic changes in freshwater ecosystems. Numerous broodstocks of the European huchen have therefore been established throughout the species’ range in recent years to supplement wild fisheries of this species. Unfortunately, this conservation management strategy entails a number of potential ecological and genetic risks associated with the release of farm-raised fish into wild populations. A comprehensive and feasible genetic monitoring protocol for broodstocks maintained for the production of restocking material is therefore essential in the sustainable management of critically endangered fish species. The current paper presents phylogenetic characteristics of four selected huchen broodstocks across Central and Eastern Europe. Genetic comparisons of the studied broodstocks were based on ten microsatellite DNA markers. The effective population size (Ne), the individual assignment test, the Principal Coordinates Analysis (PCoA), the allele sharing distance (DAS) and the Bayesian clustering analysis were applied in this study. Moreover, five selected fragments of mitochondrial DNA were used for molecular verification of species membership and genetic purity of examined specimens.

Pond culture of Chinese mitten crab (Eriocheir sinensis) in China.

Chinese mitten crab, Eriocheir sinensis, native to the coastal streams and rivers of China, is one of the most famous and widely cultured aquatic animals in China, well-known for its special appearance and delicious taste. Pond culture of mitten crab has a long history in China and culture systems vary from extensive, semi-intensive to intensive operations. This case study describes intensive pond culture techniques of the crab in relation to broodstock management, breeding, larval nursing, grow-out and harvest.

Intrapopulated Genetic Variation Of The Blue Swimming Crab (Portunus Pelagicus) From Kaimana, West Papua Indonesia Based On Cytochrome C Oxidase Subunit I (Co1) Gene Sequence

The first step to establishing appropriate broodstock management and conservation programs and to avoid decreasing genetic variability in this selective breeding program is the development of molecular genetic markers that can be used for evaluation of genetic stock determinations in gene flow rates. However, morphologically it is rather difficult to distinguish between one individual and another. The purpose of this study was to analyze genetic variation to prove differences in intrapopulated crabs. Small crab samples were collected from the district. Kaimana, West Papua. Morphological analysis was carried out by looking at differences in the color and pattern of white spots between one individual and another. The isolation of the crab CO1 gene was carried out by analyzing each individual after grouping it based on morphology. The results of the morphological analysis showed that males had seven color patterns and white carapace patterns while females had five color patterns and white spots on the carapace. However, there is little difference between morphology and genetics, especially in females, where the female is genetically divided into only two major groups. This indicates that there is information on phylogenetic relationships between individuals. The white spot on the carapace is genetically influenced so that it can be used to identify species or varieties, while the carapace color has not been shown to be influenced by the CO1 gene.