2006  Vol. 2  No. 2

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Research Paper
Abstract:

There are mainly three types of culture Chinese sturgeon, i.e., indoor intensive culture, net-cage culture and pond culture. The effectiveness of these patterns is compared in this paper. The adult Chinese sturgeons cultured in the first two patterns grow faster than those in the last one. And an adult Chinese sturgeon cultured in net cage has the highest relative growth rate (RGR) and instantaneous growth rate. Indoor intensive culture pattern needs more fund investment and higher operation cost, which is 2~3 times more than net-cage culture pattern for the same scale of production.Thus, this pattern is not suitable for large-scale promotion. Stream or reservoir with suitable condition may be chosen to carry on gravity flowing water culture. Net-cage culture pattern has higher ratio of output to input, and consumes few energy and water resource. In addition, it has obvious advantages in grow-speed, survival rate, and benefit of investment. Therefore, net-cage culture pattern is worth advocating and promoting. For pond culture, although it has low investment and cost, the survival rate is low and the effect is bad. So it is not suitable for extensive use. The result of the experiment indicated that, both indoor intensive culture and net-cage culture have low fish carrying capacity per unit area for adult Chinese sturgeon. The carrying capacity needs to be controlled about 10 kg·m-2 and less than 15 kg·m-2 for individuals of 1~3 kg.

Abstract:

In this paper, according to the theory of marine ecosystem trophic dynamic, based on the primary productivity data of the Min-zhong Taiwan Strait collected from the marine science surveys in the Taiwan Strait, by investigation of the species composition and structure of fishery resource, the content of organic carbon in phytoplankton, ecological efficiency, the trophic levels of the 61 main species, and measuring the content of organic carbon of the 58 main species. The trophic dynamic model and Cushing′ model are used to estimate the productivity of fishery resources, the trophic dynamic model and surplus yield model are used to estimate the maximum sustained yield of fishery resources. The result shows that the potential productivity of fishery resources is calculated using trophic dynamic model and Cusing model to be 38.59×104 and 43.68×104 t, respectively. The maximum sustained yield (MSY) of fishery resources is calculated using Cadima model, Schaefer and Fox model to be 25.32×104, 23.96×104 and 25.28×104 t, respectively. The maximum sustained effort is calculated using Schaefer and Fox model to be 3 372 and 3 983 of standard trawl boats in Fujian. The annual catches have been among 27.00×104~40.01×104 t since 1994, and the devoted fishing efforts are 3 897~5 976 of standard trawl boats in Fujian, which have exceeded the maximum sustained yield and the maximum sustained efforts for 11 years. The fishes′ structure of the main population is simplification, miniaturization and younger. The ecological parameters of utmost length (L) and utmost weight (W) are smaller, the growth curvature (K) is increasing, the inflexion of weight (tr) is ahead the schedule, the length of the first maturity is shorter, the fishing mortality coefficient and the ratio of exploitation are increasing, so the fishery resources decline rapidly. We must intensify the management of the fish resources, and take powerful measures to control the fishing effort and catches.

Abstract:

Based on the mean age at first maturity tα=5 a, longevity tλ=15 a, average natality b=6.4·a -1, and natural mortality coefficient M=0.279·a -1, demographic analysis was used for estimating a population intrinsic increase coefficient (r0) of 0.265·a -1, a reproductive rate per generation (R0) of 6.212, a generation time (G) of 7.571 years and a population doubling time of 2.616 years under unfished. Demographic parameters such as r0 affected by M were discussed. FC at different first capture age were calculated, and relationship between FC and tC was fitted. The results indicated that FC increased with the first capture age. When tC > 5 a, the population will not decrease with capture.

Abstract:

Based on the survey data in polyculture pond system of Gracilaria tenuistipitata v. and Penaeus monodom in Lian′an town Haifeng county Guangdong province, China from April 2002 to September 2003, a neuro-fuzzy system model was developed to describe the non-linear relationships among the biological and physicochemical factors in pond in different growth phase of Penaeus monodom. The model simulated the theoretic lowest growth rate of Gracilaria tenuistipitata v. in different growth phase of Penaeus monodom within the eutrophication restrict criteria of dissolved nitrogen in water DIN≤0.2 mg·L-1. The simulated results well reflected the effect of actual growth rate of Gracilaria tenuistipitata v. on the DIN in polyculture pond system.

Abstract:

Based on the investigation data of fishing production in the coastal waters of Fujian in 2000 and 2002, eight fishers with varied power vessels have been studied in comparison. The study using DEA method and 2 output factors, which are actual catch value of input factors, and technology fund etc. to calculate their fishing integrative capacity. The results showed that the capacity utilization of different power vessels of 8 fishers varied from 58.4% to 100% with an average value of 85.7%, among them, the capacity utilization of set net, pot funnel, single trawler, drift gill net and light-purse seine with giving invested factors is higher, hook and line and pair trawler is second, and shrimp beam trawl is lowest. The no-deflection capacity utilization varied from 36.9% to 100% with an average value of 71.8%, among them, its of light-purse seine, set net and hook and line is higher, drift gill net and single trawler is second, beam-shrimp net and pot fishing is lower, and pair trawler is lowest. If the equipment situation don′t change, the fishing capacity of single trawler, pot and set net is finite improved which depends on strengthening management, however its of beam-shrimp net, drift gill net, light-purse seine, hook and line and pair trawler obtain a different extent improvement. Alterable input can restrict fishing integrative capacity of different fishery to exert, and influence of immutable input is relative lesser. Now, the potential integrative capacity of fishing vessel less than 220 kW and the vessel of pair trawler and light-purse seine less than 300 kW is larger and must become main adjusted object of fishing structure. Aggregative degree of DMU is higher that capacity utilization calculating by using of DEA increases, otherwise the capacity catch and value decrease.

Abstract:

According to the shrimp survey data of four seasonal months in the Northeast Fujian outer-sea (26°00′~28°00′N, 120°00′~125°30′E), this paper studied and analyzed the quantitative distribution and biological characteristics of Solenocera alticarinata. The results showed that the average density of its resource in May, August, November and February were 34.7, 13.8, 4.55 and 2.89 kg·km-2, respectively. The quantitative distribution was obvious different from the seasons with May and August being more and November and February being less.The area of high biomass density occurs in the northeast waters of the survey sea and the highest occurs in the waters at depth of 80 to 100 m (27°00′~28°00′N, 122°30′~124°30′E). The body length varied between 41 and 129 mm, the dominant were between 80 to 100 mm occupying 44.7%. The female was obviously larger than the male with the sex ratio 1:0.66, the average body weight was 12.0 and 8.3 g, respectively. There was no obvious difference for feeding intensity from the seasons or between different sex.

Abstract:

In order to achieve all information about enzyme in Tilapia organ, it′s necessary to make a comprehensive study on enzyme. Enzyme activity and enzyme quantity were used as parameters to evaluate enzyme score. Protease, chymosin, urease, superoxide dismutase (SOD), cholinesterase, acetylcholinesterase, alkaline phosphatase and acidic phosphatase in Tilapia organs were studied in this paper. The results showed that the enzyme activity and enzyme quantity of protease, chymosin, SOD and alkaline phosphatase were higher than others, and it′s worthy to be studied further.

Abstract:

Recent questionnaire data, from trainees of 20 foreign developing countries of Asia, Africa and Southern America in 2004 Training Course for Integrated Fish Farming of Technical Cooperation among Developing Countries (TCDC) program, were analyzed on most common aquaculture species, environmental impacts from aquaculture and needed strategies for elimination of the impacts. Results suggested that there was great diversity of species in aquaculture activities in the countries studied and about 90 species were recorded including fishes, crustaceans, mollusks, sea weeds and so on. Species in traditional food aquaculture was more than those in recent business aquaculture in every country except for Thailand. The most significant environmental impacts seemed to be effluent, habitat destruction, chemicals, and heavy fishing of natural parent fishes and fries. Those of biological pollution by escapees, transportation of diseases, high pressure on pelagic fish, and by-catch took a second place rank. Effective strategies for elimination of these impacts are urgently necessary in mechanism research, alternative technology, relevant education system and supportive policy for the developing countries in the present study.

Research Notes
Abstract:

Based on mesh selectivity data of trawl codend tested in the offshore waters of Northern South China Sea in October 1997 and in November 2000, catch selectivity of 30.3 mm square mesh codend was analysed. The results indicated that the average escape rates of 30.3 mm square mesh codend for catch were 29.76% in number and 8.46% in weight. There were lesser and fewer in commercial species and its numbers in the cover net, and the sum of Nemipterus virgatus, Saurida tumbil, Upeneus bensasi, Trachinocephalus myops comprised 95.4% in number and 86.0% in weight of sample catch in the cover net, respectively. The high percentage of juvenile commercial species that were undersized in the codend showed 30.3 mm square mesh codend had more serious damage to most juvenile commercial species, approaching or exceeding 50% in percentage of juvenile species which body length is smaller than fishable size—Trichiurus haumela, Priacanthus tayenus, Navodon tessellatus, Argyrosomus argentatus, Nemipterus bathybius and so on, even exceeding 90% in percentage of juvenile Sepia spp, Loligo spp and Parastromateus niger. In particular, 50% selection lengths (L0.5) caught Saurida tumbil and Nemipterus virgatus were smaller than their minimum fishable size. To sum up, the use of 30.3 mm square mesh codend will make against sustainable utilization to most fishery resource and biodiversity protection in Northern South China Sea.

Abstract:

In this paper, firstly, the acute toxicity of triazopnios with different density on Charybdis japonica was determined, and we obtained that the safety concentration was 0.27 mg·L-1. And secondly, effects of 0.27 mg·L-1 triazopnios accumulation on protective system in 5 tissues (muscle, gill, hepatopancreas, heart and sex gland) were studied. The results showed as follows: (1)Enzymes of protective system of C.japonica included SOD and CAT, and POD was not detected and measured in those tissues.(2)SOD and CAT activities exhibited significant differences among different tissues, and the orders of SOD and CAT activity from high to low were heart > gill and muscle > sex gland and hepatopancreas, sex gland > hepatopancreas > heart > gill and muscle, respectively.(3)SOD and CAT activities in test group would change relatively when compared to the control group. Low levels of the chemicals could stimulate SOD and CAT activity, while the activity would decrease with high level. (4) The sensitivities of SOD and CAT to the poison in gill, sex gland and hepatopancreas were much more than those of heart and muscle.

Abstract:

The activities of digestive enzymes in three alimentary organs of Lutjanus sebae were detected and compared. The results showed that the protease activity was intestine > stomach > hepatopancreas (P < 0.01);and the amylase activity was intestine > hepatopancreas > stomach (P < 0.01);and the lipase activity was intestine > hepatopancreas > stomach. The lipase activity difference between intestine and hepatopancreas or stomach was significant (P < 0.01), but the difference between hepatopancreas and stomach was not significant (P > 0.05). The digestive activities of intestine in young L.sebae were high. The stomach and hepatopancreas were auxiliary organs.

Review
Abstract:

Haliotis diversicolor diversicolor and H. diversicolor supertexta with a high commercial value are main farming species of abalone aquaculture in South China. There are different opinions on systematic relationship between the two abalones in academic community. The paper summarized the major research progress on germplasm resources of morphology, chromosome karyotype, biochemical genetics and molecular genetics of H. diversicolor diversicolor and H.diversicolor supertexta. All the results indicated that the genetic differences between H. diversicolor diversicolor and H. diversicolor supertexta are small and probably just at the population level. Their differences are short of the subspecies level. The author submitted the new idea about those. Meanwhile, the measures to transfer and protect the germplasm resources in reason of abalones was put forward.

Abstract:

This paper introduce the structure and pharmacological character of ciguatoxin, its extraction and chemical synthesis, the poisoning symptom, the presentd poisoning situation and the means of analysis. The thesis is significant to help people understand ciguatoxin and prevent poisoning of ciguatoxin.

Abstract:

The United States and the People′s Republic of China are playing the most important role in the foreign trade of Tilapia. China is honored for its greatest capacity of export and production, meanwhile, US is the biggest Tilapia import and consumption country of the globe. Taking the full advantage of domestic potentials to augment quantity and upgrade quality of the Tilapia products, we also should be scrupulously aware of the dynamics of international market, which is the key of success in the increasingly drastic competition. Scrutinized the profiles of recent Tilapia market information, this article analyzed the phenomena pertinent to US Tilapia trade with regards to the import country, import quantity and value. The authors have worked to present suggestions and outlooks of Tilapia market with the intention of providing consultative references for the local fishery industries and institutes.

Abstract:

The pollution sources of petroleum in the marine environment include natural and man-made ones, and man-made source is the major one which impact marine ecology and fishery. Crude and refined oil have different compositor, chemical instructor and molecular mass. So their toxicity to the marine creature is different. The endurance of marine organism to the petroleum pollution is also different. Benthic organism can endure much more high concentration of petroleum. Some plants can restore the level of pro-pollution in a short time. The fish and zooplanktons are sensitive to the oil pollution. But some abnormal phenomena were found in some fishing grounds that puzzled us.