Antithamnion sparsum , its life history and hybridization with A. defectum in culture
MetadataShow full item record
Antithamnion sparsum isolated from the southern and western coasts of Korea showed a basically Polysiphonia -type life history. However, it sometimes exhibited a monoecious reproduction and the carpospores released from the cystocarp by self-fertilization unexpectedly developed into plants bearing spermatangia alone. These male plants were not functional up to 60 days in culture. The results of intraspecific crosses between populations of A. sparsum were successful and the hybrid carpospores gave rise to normal tetrasporophytes. On the other hand, the interspecific crosses between A. sparsum and A. defectum were only partly successful, as evidenced by gonimoblast development and the release of carpospores in case of A. sparsum (male) x A. defectum (female), but not in A. sparsum (female) x A. defectum (male). These results seem to suggest that both species are still undergoing speciation.
Lee, I. K., & Boo, S. M. (1990). Antithamnion sparsum , its life history and hybridization with A. defectum in culture. In I. J. Dogma Jr., G. C. Trono Jr., & R. A. Tabbada (Eds.), Culture and use of algae in Southeast Asia: Proceedings of the Symposium on Culture and Utilization of Algae in Southeast Asia, 8-11 December 1981, Tigbauan, Iloilo, Philippines. (pp. 39-49). Tigbauan, Iloilo, Philippines: Aquaculture Department, Southeast Asian Fisheries Development Center. http://hdl.handle.net/10862/189
PublisherAquaculture Department, Southeast Asian Fisheries Development Center
Showing items related by title, author, creator and subject.
Conference paperAC Emata - In TU Bagarinao & EEC Flores (Eds.), Towards sustainable aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994, 1995 - Aquaculture Department, Southeast Asian Fisheries Development CenterMost of the fish research at SEAFDEC AQD in 1992-1994 was on milkfish. Studies were conducted on year-round spawning through hormonal or environmental manipulation; optimum lipid and protein levels and ration size for captive broodstock; and the influence of spawner age on reproductive performance. The economics of hatchery operations, alone or integrated with broodstock as a commercial enterprise, was assessed. Mass production of larvae was refined with the use of commercial or SEAFDEC-formulated larval diets. Alternative rearing schemes in large tanks and ponds were tried. Hatcheryproduced and wild-caught larvae were compared in terms of growth and production in experimental nursery and grow-out ponds. Supplemental diets for brackishwater grow-out culture were formulated. Studies on broodstock management of grouper Epinephelus spp. included lipid enrichment of the diet and hormonal induction of sex inversion. Seed production techniques were developed but survival rates were low. Grouper culture was found economically feasible in experimental ponds with 'trash' fish as feed. The mangrove red snapper Lutjanus argentimaculatus was successfully induced to spawn with injection of human chorionic gonadotropin. Initial larval rearing trials were successful but survival rates must be improved. Hormonal manipulation of spawning of the Asian sea bass Lates calcarifer allows seed production during most of the year. Photoperiod manipulation leads to maturation of females, but not males, beyond the natural breeding season (April-November). Nursery rearing of 9 mm juveniles is feasible in floating net cages with night lights that attract food zooplankton. The requirements of sea bass for lipid, protein, carbohydrates, and essential amino acids were determined. In the rabbitfish Siganus guttatus, weekly injections of luteinizing hormone releasing hormone analogue (LHRHa) sustains milt production for three weeks. Thyroid hormones injected into broodstocks improved the growth of larvae to day 7. Induced spawning techniques for the Asian catfish Clarias macrocephalus were refined by determining the seasonal responsiveness to LHRHa and pimozide injections and testing for pheromonal induction of spontaneous spawning. The optimum insemination rate was determined and egg hatchability was enhanced by removal of the adhesive coat before incubation. Several practical diets for catfish during grow-out culture were tested against 'trash' fish. The broodstock management for bighead carp Aristichthys nobilis was studied. Cage-reared juveniles from cage-reared broodstock showed the best growth. To improve the reproductive performance, the broodstock diets were supplemented with vitamins A, C, and E. Research on tilapias focused on genetics and strain selection. Several strain testing procedures for Nile tilapia were evaluated in their efficiency to detect economically important strain differences. Reference lines were developed from two existing red tilapia strains to measure and reduce the effects of uncontrolled nongenetic variables in strain evaluation experiments with Nile tilapia. The tolerance of two Nile tilapia strains to heavy metals was similar when gauged by the 24-hour and 96-hour lethal concentration and by fish growth, survival, and reproductive performance. In a separate study, four strains of red tilapia showed generally higher seed production when reared in tanks than in cages. Improvements in the feed and feeding management for Nile tilapia were also studied. Intensive tilapia farming and feeding have led to oxygen depletion and fish kills in Sampaloc Lake. To rehabilitate the lake, it is imperative to reduce the farming area from 30 to 6 hectares; stop the use of commercial feeds; and remove the water hyacinths and other debris. Fish kills in Laguna de Bay have also become serious in recent years, and a review of the occurrences, losses, and possible causes is currently being conducted. Studies on the epizootic ulcerative syndrome of snakeheads in Laguna de Bay have yet to pinpoint the pathogen. Skin lesions in tilapias in several ponds and lakes in the country were found to be due to bacteria.
Effect of Epinephelus coioides, Chanos chanos, and GIFT tilapia in polyculture with Penaeus monodon on the growth of the luminous bacteria Vibrio harveyi Studies have shown that the presence of Tilapia hornorum hybrid has antibacterial effect against luminous bacteria. The present study aims to determine the effect of different fish species such as grouper, milkfish and tilapia in polyculture with shrimp on the growth of luminous bacteria. Results showed that stocking of tilapia Oreochromis niloticus hybrid and grouper Epinephelus coioides at a biomass of 500 g/m3 efficiently inhibited the growth of luminous bacteria in shrimp (biomass = 80 g/m3) rearing water and positively affected shrimp survival. Results also showed that the presence of milkfish Chanos chanos at a biomass of 500 g/m3 did not inhibit the growth of luminous bacteria in shrimp (biomass = 80 g/m3) rearing water.
Conference paperMRR Romana-Eguia & EGT de Jesus-Ayson - In BO Acosta, RM Coloso, EGT de Jesus-Ayson & JD Toledo (Eds.), Sustainable aquaculture development for food security in Southeast Asia towards 2020. Proceedings of the Regional Technical Consultation on Sustainable Aquaculture Development in Southeast Asia Towards 2020, 2011 - Aquaculture Department, Southeast Asian Fisheries Development CenterAsia is a major contributor to world aquaculture production. Most Asian countries have maintained their rank in the ten top aquatic food producing nations after developing refined techniques for major commercially important aquaculture species and promoting an increased awareness on the merits of using quality seeds (genetically enhanced or otherwise) as supplied in sufficient quantities. Quality seedstock simply means fit, clean , uniformly-sized seeds which could be eggs, fry, fingerling, juveniles and/or plantlets (for seaweeds) that subsequently express good performance attributes during culture. Beneficial traits refer to good color, shape, growth, efficient feed conversion, high reproduction, tolerance and survival when exposed to stressors (e.g. diseases, poor and/or extreme environmental conditions). Such traits are mostly heritable, hence, quality seeds are usually assumed as produced only by mating stocks perceived or proven to be genetically superior. Some bloodstocks may be genetically mediocre but if bred and manage properly through efficient farm protocols (suitable hatchery, nursery feeding and water management methods), may also produce good quality seeds. Success in the sustainable production of aquatic species for human consumption depends primarily on the availability of seedstock and adoption of optimal husbandry techniques among others. With the intensification of aquaculture systems and the environmental challenges such as those resulting from climate change, it is wise to continue considering both factors -- genetic quality and culture management as equally important in ensuring a steady production of good quality seeds and later, marketable products from aquaculture. Views on what, how and why better quality aquaculture seeds should be produced evolve as times change. To understand these concerns, this paper will cover: (a) the present state of fish seed production in Asia, (b) recent and current seedstock production issues that require attention, and (c) recommendations on how to further enhance aquaculture production in the region in the next decade through better quality seedstock.