Now showing items 1-3 of 3

    • Conference paper

      Application of DNA-based markers in stock enhancement programs 

      MRR Romana-Eguia - In JH Primavera, ET Quinitio & MR Eguia (Eds.), Proceedings of the Regional Technical Consultation on Stock Enhancement for Threatened Species of International Concern, Iloilo City, Philippines, 13-15 July 2005, 2006 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Aquaculture and fisheries management require tools for identifying individuals or groups of aquatic organisms for the purpose of monitoring performance (growth, survival and behavior) and stock structure. In aquaculture research, commercially important traits of tagged individuals are assessed to generate supportive data for selective breeding, genetic improvement and commercial-scale fish farming. Fisheries management employs identification systems for the evaluation of stock abundance, population dynamics and documentation of wild and hatchery-bred stocks. Stock structure analysis is useful in the planning and implementation of sound stock management and more importantly, in stock enhancement programs. Blankenship and Leber (1995) underscored the inclusion of tagging/marking strategies for released hatchery stocks in the guidelines for responsible marine stock enhancement. Identifying and keeping track of introduced stocks in release habitats allows an assessment of their adaptability in the wild (Allendorf et al., 1988) and the success of the reseeding and/or restocking effort. Although often used interchangeably, the terms ‘tags’ and ‘markers’ differ by definition. Tags are artificial or synthetic materials that are attached to the aquatic organism to allow individual or group identification while markers are traits or characters either applied or inherent to the organism (Thorsteinsson, 2002). Tags/markers are essential in evaluating resource distribution patterns, behavior, migration and movement of stocks, dynamics of exploited aquatic populations and evolutionary processes, all of which comprise baseline information for any stock management, enhancement and conservation program in aquaculture and fisheries (Allendorf et al 1988, Mulvey et al., 1998).
    • Article

      Effect of streamer tags on survival and growth of juvenile tiger prawns, Penaeus monodon, under laboratory conditions 

      JH Primavera & RM Caballero - Marine and Freshwater Research, 1992 - CSIRO Publishing
      The effects of streamer tags and initial prawn size on survival and growth in 2-month- and 7-month-old pond-reared juveniles of Penaeus monodon Fabricius (11-30 mm carapace length, CL) were assessed under laboratory conditions. Tagging did not cause immediate mortality in juveniles of 11-21 mm CL within a one-week period but led to a significantly lower survival rate after 6 to 8 weeks in 1-m3 tanks. However, tagged prawns of 21-30 mm CL showed high long-term survival rates up to 90% in a 12-m3 tank. The 2-month-old juveniles had lower survival rates than 7-month-old prawns. Specific growth rate was not affected by tagging but was significantly higher in smaller prawns. In general, there was no interaction between the effects of tagging and prawn size in terms of growth and survival rates.

      The lower long-term survival rate associated with tags may be due to the attractiveness of tags to predators, or to trauma or stress caused by the weight of the tags. These factors are discussed in relation to findings for other penaeid species.
    • Article

      An inexpensive tag for short-term studies in milkfish (Chanos chanos Forsskal) and in seabass (Lates calcarifer Bloch) 

      LMB Garcia & RSJ Gapasin - Journal of Applied Ichthyology, 1988 - Blackwell Publishing
      An opercular tag for marking adult milkfish (Chanos chanos Forsskal) and seabass (Lates calcarifer Bloch) is described. High tag retention and relatively low mortality rates were observed in adult fish handled two to ten times during 14-to 60-day tests. The features and advantages of the tag for marking large-sized fish in short-term studies are discussed.