Showing items related by title, author, creator and subject.

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  Size and diel differences in activity patterns of Metapenaeus ensis, Penaeus latisulcatus and P. merguiensis 

  Primavera, Jurgenne ; Lebata, Ma. Junemie Hazel L. (Taylor & Francis, 2000)

  The nursery function of mangroves as shelter has been postulated to explain the positive correlation between shrimp catches and mangrove area. This study was undertaken to document shelter use and other activities in mangrove‐associated penaeids and to determine diel and size differences relating to these activities. Juvenile Metapenaeus ensis, Penaeus latisulcatus and P. merguiensis collected from mangrove areas in Guimaras, central Philippines and stocked individually in glass tanks (= replicates) provided with artificial shelters and sand substrate were observed every hour for 25 h. Size classes tested were very small (1–5.9 mm carapace length); small (6–10.9mm CL); medium (11–15.9mm CL); large (16–20.9mm CL); and very large (21–25.9 mm CL). Due to limited juvenile supply, only 3 sizes were tested for each species: P. merguiensis (very small to medium), M. ensis (small to large) and P. latisulcatus (medium to very large) with 5 replicate animals (one per tank) per size. Juvenile M. ensis and P. latisulcatus showed a strong diel periodicity of daytime burial and nocturnal activity. In contrast, P. merguiensis showed active swimming and feeding throughout the day and night. Very small to small P. merguiensis were observed on the shelters, but burying was exhibited only by a few medium‐sized juveniles. This shelter use is consistent with observations of small P. merguiensis entering the mangrove forest (where roots, twigs, etc. contribute to structural complexity) on the flood tide and concentrating in the shallow, turbid waters of adjoining creeks during ebb tide and slack water.
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  The shrimp farming industry in the Philippines 

  Corre, Valeriano, Jr. (Aquaculture Department, Southeast Asian Fisheries Development Center, 1993)

  The shrimp farming industry in the Philippines is the culture of shrimp (Penaeus monodon) in brackishwater and seawater grow-out farms to marketable size. The industry is highly dependent upon the other sectors/components of the shrimp culture industry, including:

  1. the shrimp hatcheries for their supply of fry (PLs);
  2. the feed millers for their supply of commercial pelletized feeds, primarily for semi-intensive and intensive shrimp farms;
  3. the shrimp processors/exporters for the purchase of their harvests;
  4. the financial institutions for their capital and operational costs; and
  5. the research institutions and the government for solutions to technical and other problems.

  Such dependence makes shrimp farming vulnerable. Other than that, it is also a high risk business. In addition, monsoon rains, typhoons, and floods can significantly affect shrimp farming. Pollution from watershed activities and from self-generated organic load has resulted in slower shrimp growth, higher susceptibility of shrimp to diseases, and mass mortalities. Widely fluctuating export market prices and demands are also major concerns of the industry.
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  Series: Developments in Aquaculture and Fisheries Science; 23

  Prawn/shrimp culture industry in the Philippines 

  Primavera, Jurgenne (Elsevier, 1992)

  The Philippines is an archipelago of more than 7,100 islands with 17,460 km of coastline, including mangrove forests which covered about 450,000 ha in the 1920s. Coastal aquaculture began a few centuries ago when earthen ponds for the culture of milkfish (Chanos chanos) were first converted from mangrove swamps. For a long time, coastal aquaculture was synonymous with milkfish pond culture; while prawns and shrimps were incidental byproducts resulting from wild fry that entered the ponds during tidal water exchange. In 1943, studies on low density monoculture of the giant tiger prawn (Penaeus monodon) using wild fry were initiated at the Dagat-dagatan Experimental Station of the Bureau of Fisheries in Malabon, Rizal Province. Information on the ecology and early life history of P. monodon generated by the Institute of Fisheries Research Development of the Mindanao State University (MSU-IFRD) in the early 1970s was used in setting up the first experimental prawn hatchery at IFRD. This was followed by the establishment of big-tank and small-tank hatcheries at the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) in Iloilo Province. An active technology transfer program that included short-term, hands-on training courses on small-scale hatchery starting in 1977, contributed to a dramatic hatchery production of 15 million prawn PL in 1978. Based on the earlier Dagat-dagatan studies, SEAFDEC/AQD started higher-density (semi-intensive) growout pond experiments with P. monodon in the mid-1970's. At that time, farmers started stocking more than 10,000 PL/ha using hatchery fry. Soon after, the first intensive culture trials, using imported Taiwanese technology and feed formulations were undertaken by a Philippine food conglomerate. The availability of both seed and feed, and the attraction of lucrative export market prices contributed to the take-off of the prawn industry. In 1983, when the country's 56 hatcheries produced 85 million PL's, and commercial pellets for intensive culture first appeared in the market, pond production totalled 12,100 MT, a quantum leap from a harvest of only 1,800 MT the previous year. Since then production of PL, adults and exports have steadily increased to a peak of 20,000 MT of exports from 40,000 MT of pond harvests in 1988. The following year the bubble burst. From a high of P200/kg (US$1 =P21) in 1988, farm gate prices plummeted to as low as P70/kg in mid-1989 due to Southeast Asian excess production of black tiger prawn, and to prawn exports from China glutting the Japanese market. This chapter discusses the various components of the Philippine prawn industry with a focus on growout, problems of the farming sector, and problems of the industry as a whole. Lastly, recommendations are offerred for long-term viability.