海洋捕捞结构调整对渔业经济的影响及其对策

为了持续发展福建省海洋捕捞业，必须实施海洋捕捞产量“负增长”的战略，并对现有的海洋捕捞结构进行调整。随着产量的减少，渔获品种的变化，海洋捕捞业的经济效益必定受到影响，如何在产量减少的情况下，保持海洋渔业经济持续增长，这是一个棘手的问题。本文以福建省海洋捕捞业为例，分析了海洋捕捞业产量“负增长”及作业结构调整对渔业经济的影响，提出海洋捕捞结构调整后，发展海洋渔业经济的对策及思路。     

海水小瓜虫生活史及白点病防治

在集约化海水养殖过程中，很多寄生性原虫都能很好地生长繁殖，其中，海水小瓜虫是致病性最强的原虫之一。海水小瓜虫学名为刺激隐核虫（Cryptocaryon irritans），是一种遍生性（周身遍布纤毛）纤毛虫，通常寄生于热带、亚热带海水鱼类的体表和鳃上，形成针头大的小白点，所以生产上俗称“白点病”。该寄生虫会引起鱼的活动异常、上皮增生、呼吸困难以及机械损伤，继而带来病菌的继发感染。在自然情况下，野生的海洋鱼类很少受到海水小瓜虫的严重感染，因为宿主的聚集密度不够，虫体的繁殖量不足以达到严重感染的程度。然而，在水泥池、室内的水族箱或渔排的网箱等高密度鱼类养殖场所，虫体就能在短时间内大量繁殖而致病。     

Histamine and Histidine in New Zealand Marine Fish and Shellfish Species,Particularly Kahawai (Arripis trutta)

Forty-seven retail samples of fish (28 species) were tested for levels of free histidine, histamine and aerobic plate counts. Five samples had elevated levels (≥ 20 mg/100 g) of histamine and all had < 100 mg/100 g. Three species had free histidine levels of more than 1000 mg/l00 g and these have been implicated in scombroid poisoning in New Zealand. One species with high histidine levels, kahawai (Arripis trutta), was chosen to determine the conditions under which potentially hazardous levels of histamine might develop. Two trials were carried out in which kahawai were stored under 17 regimes at temperatures between 0 and 35°C. For 10 of these treatments the fish were transferred from elevated storage temperatures to refrigerated storage during the trials. Levels of histidine and histamine, aerobic plate counts at 20°C and 35°C and sensory quality were monitored. The levels of free histidine in kahawai varied with season, and in Trial 2 there was a net loss of histidine + histamine during storage. Bleeding kahawai did not significantly affect the levels of histidine. Histamine levels varied greatly in fish held under identical conditions. Fish held at ambient temperatures developed the highest levels of histamine. Elevated histamine levels (> 20 mg/100 g) were first recorded in fish stored for 0.9, 0.9, 1, 2, 2.7, and 8 days at 35, 30, 25, 20, 15 and 10°C respectively. Storage at 5°C after storage at higher temperatures did not result in elevated levels. Of the 59 samples with elevated histamine levels, 9 had acceptable sensory characteristics while all had aerobic plate counts exceeding 10⁶ colony-forming units/g. Aerobic plate counts at 20°C are recommended over those at 35°C. It is concluded that fresh kahawai will only present a hazard from scombroid poisoning under conditions of extreme temperature abuse and that the presence of high numbers of bacteria is a good indicator of the hazard while sensory quality is not.     

Larviculture of Mediterranean Marine Fish Species: Current Status and Future Trends

The larviculture of Mediterranean marine fish species has focused on the production of Spurus auruta and Dicentrarchus labrar . European fry production of these species has increased from 12 million in 1987 to 28 million in 1989 and is expected to rise to nearly 40 million fry in 1990.
Within differing hatchery systems, larval survival has been improved through the use of commercially available w3-HUFA rich live food enrichment diets. This combined with the use of surface cleaning techniques has led to a standardization of larval rearing procedures enabling mass production of quality fry. Increased concern with larval hygiene has resulted in larger larval rearing batch production and regular sterilization periods in most European units.
Market pressure is stimulating established producers to diversify their species range and industrial quantities of Puntazzo puntuzzo , and Pagrus major are already being produced. Work has started on the larval culture of Dentex dentex, Pagrus pagrus and Seriola dumerilli .     

Fisheries production in Southeast Asian farmer managed aquatic systems (FMAS): I. Characterisation of systems

Southeast Asian rice farmers often manage aquatic habitats and resources on their land to increase production of aquatic animals. We introduce the concept of ‘farmer-managed aquatic systems’ (FMAS) to capture the diversity of these resource systems at the interface of aquaculture and capture fisheries and characterize FMAS in contrasting agro-ecosystems of Cambodia, Thailand and Vietnam. Cambodian and Thai FMAS yielded primarily self-recruiting species (SRS) and were managed to allow or attract them, while Vietnamese FMAS were managed more intensively to produce mostly hatchery-reared species. More than 90% of rice farming households in the study areas of Cambodia and Thailand harvested aquatic animals from their land, and about 70% created aquatic habitats such as ponds in addition to rice fields in order to increase aquatic resource production. Cambodian households created and utilized a wide variety of man-made aquatic habitats, while Thai households created predominantly trap ponds. In contrast, less than half of Vietnamese farming households harvested SRS and very few undertook FMAS management specifically for them. Vietnamese FMAS were intensively stocked and managed as aquaculture systems, with SRS accounting for less than 30% of production. Nonetheless, SRS production per area of FMAS was comparable in the three countries. Contrasting FMAS characteristics in different study areas reflect underlying differences in agro-ecosystems, aquaculture technologies, farmer livelihoods and markets.     

满江红Azolla imbricata ( Roxb.) Nak的生物学特征及其渔业利用

满江红(Azollaimbricata)天然资源丰富,产量高,渔业利用价值比较大。论文综述了近年来满江红的部分研究工作,介绍了满江红的生物学特征及其渔业利用,在前人的基础上,提出利用“鱼类—满江红”走生态养殖的模式。