碩士 / 國立海洋大學 / 漁業科學系碩士在職專班 / 91 / Abstract
For understanding the current species of Family Tetraodontidae, this study is intended as an investigation in the northeast waters off Taiwan, compiles a comparative list of puffers in scientific name, common name, Taiwanese, Chinese, and Japanese for reference, and probes into the bio-characters and the edible safety of the main species-- Lagocephalus gloveri.
Total 385 specimens of puffer, 8 species including Lagocephalus gloveri, are collected from set-net fishing groundings in I-lan County. According to a bibliography, other species, except an unknown toxicity of Boesemanichthys firmamentum, are somewhat poisonous. Processed Lagocephalus gloveri especially, the toxin tends to be concentrated in the fish’s gonads. In general, the occurrence and amount of toxin is related to the fish’s reproductive cycle. More toxin is usually present during peak reproductive (spawning) times.
The results of the bio-characters are summarized as follows:
1. Fishing seasons
According to a bibliography and interview with fishermen, the fishing seasons of Family Tetraodontidae are between October and May in the next year, and the specimens in the study were collected from October in 2002 to the middle of July in 2003, but for the lack of specimens in October, June and July, the result is similar to the bibliography and description fishermen said. Thus it is presumed that the fishing seasons of Lagocephalus gloveri are between in November to May in the next year.
2. Standard body length
The standard length of female fish is with a range between 22cm to 41.5 cm, and the male is between 21cm to 34 cm.
3. Variation between G. S. I. and H. S. I.
According to the variation of monthly averages of G.S.I., frequency distribution and observation of gonads on tissue biopsy of females and males, it is knowable that the growth and development period of fish’s ovary is between February and May, and the growth period of testis is from January. Both growth and development reach a peak around in May, but the H.S.I. presents on a downside between before the gonads development and in development. In which, it seems that the variation of female’s H.S. I. is connected with the development of vitellogenin and the supply of essential energy for ovary’s development. Although the male is free of vitellogenin, it also needs to consume the energy for the development of gonads and releasing sperm, therefore, G.S.I. and H.S.I. are also on a downside.
4. Fullness
Fullness is presented by muscle or how much substance fish keeps; besides, the amount of environmental live food, whether the reproductive times those are great effect on fish’s fullness. In general, fish always consumes large energy for spawning or releasing sperm during the reproductive times, so the fullness mostly reduces. However, the fullness of Lagocephalus gloveri seems not to follow the rule, it may because of the rich live food in the northeast Taiwan and Family Tetraodontidae’s habitual behavior of greedy for food.
5. Sex rate
Between February and May is the growth period of female’s and male’s gonads. Males are obviously more than females which the special phenomenon could be caused by great spawning species, or because of habitual behavior the parts of female’s ovaries are mature, so fish community move to other habitats for spawning.
6. Relationship among toxicity, G.S.I. and seasons
The level of toxicity of Family Tetraodontidae depends on the growth of fish’s gonads, on the other word, the more G.S.I. raises, the higher toxin fish has, particularly in spring (between March to May). The study reveals that the growth to maturity of female’s and male’s gonads is between February and May in which time G.S.I. is higher and the toxicity gets stronger.
7. Relationship among temperature, growth and maturity
According to a bibliography, there has a close relationship among sex maturity, spawning and water temperature. While the water reaches an optimum temperature for spawning, fish will get mature and then spawn. The study shows that the growth and maturity of female’s and male’s gonads mostly occur between February and May, and the water temperature is between 22 to 28 degrees centigrade. Therefore, over 20 degrees centigrade of water temperature is helpful for the growth and being mature to Lagocephalus gloveri.
In the cause of safety for eating puffers, it is not only to attach importance to the education for preach, training for techniques of sanitization, and reinforcement of sanitation inspection; but also to implement the related management regulations effectively; meanwhile, the government authority should revise the related regulations to raise a reward for reporting on violators, and multiply the penalty to promote management efficiency. Moreover, to coordinate with the goal of “one country with one specialty” by government, the authority should make guidance and assistance to puffers industry, set up a production and marketing work group for processed puffers, and bring it into the alliance of transportation and sale of processed aquatic products to make full use of fishery resources and benefit fishermen. In addition, the authority should actively conduct a workshop for development and management of puffers industry, invite fishermen, processing proprietors to take part in and appreciate guidance from public health commissioners, fishery administrators, scholars and experts. By experience exchange, proprietors can improve the techniques of production and management on puffers, and the opinions by participants could be as reference materials to government.
| Identifer | oai:union.ndltd.org:TW/091NTOU1451010 |
| Date | January 2003 |
| Creators | WANG,MEIL-LING, 王美玲 |
| Contributors | Huang Bao-Quey, 黃寶貴 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 135 |
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