海南省外来淡水生物入侵现状、危害及防控策略

由于特殊的地理环境和良好的气候条件,海南省已成为我国外来生物入侵的重灾区之一,许多外来淡水生物在海南均有分布。2016-2018年,对万泉河、南渡江、昌化江等海南主要河流外来淡水生物的种类和分布进行了初步调查。经过调查发现,目前海南共有43种外来淡水水生生物,其中鱼类31种、爬行类2种、两栖类1种、软体动物2种、甲壳动物3种,淡水植物4种。海南省外来淡水生物的主要入侵途径是水产养殖引种,主要危害是捕食和竞争。根据调查结果提出了健全管理制度、加大科学研究和人才培养、加强宣传等防控策略。     

休闲渔业的现状与在我国的发展对策

20世纪60年代以来，休闲渔业在一些经济较为发达的沿海国家和地区迅速崛起，将休闲、娱乐、旅游、餐饮等行业与渔业有机结合为一体，提高了渔业的社会、生态和经济效益，形成一种新型产业。休闲渔业已经成为现代渔业的重要组成部分，并在渔业资源保护、促进渔民增收、调整渔业产业结构等方面都有其不可忽视的作用。然而，作为一种新兴产业的发展，必然要有配套的规划和管理，本文对这一问题进行了深入研究，并提出了一些对策。     

福建省光诱敷网作业发展前景及管理研究

福建省的光诱鱿鱼敷网作业是福建省渔民在近十几年发展起来的一种用来专门捕捞枪乌贼的新型渔具.它具有投资少、生产费用低、劳动强度小、捕捞效率好、经济效益高等优点.目前其捕捞枪乌贼的产量已占所有作业捕捞枪乌贼产量的三分之二以上.然而,近年来,由于该作业的迅速发展,也带来了如诱集枪乌贼的灯光强度过大,渔获物中的幼鱼比例增多,渔场矛盾等问题.为了科学有效管理该作业,本文通过收集有关资料,整理分析,提出促进光诱鱿鱼敷网作业可持续发展的一些建议.     

Optimising codend configuration in a multispecies demersal trawl fishery

Abstract The relative efficiencies and selectivities of conventional and modified codends were examined in a demersal trawl fishery targeting several species, including eastern king prawns, Penaeus plebejus (Hess), whiting, Sillago spp. and cephalopods. The modifications to codends included: (i) reducing the circumference; (ii) increasing the mesh size in conventional diamond‐mesh designs; and (iii) orientating meshes on the bar so that they were square shaped. The codends were tested against a fine‐meshed control in paired comparisons onboard three commercial trawlers. The conventional codend comprised 41‐mm diamond‐shaped mesh attached to an anterior extension section at a ratio of 150 to 100 meshes and was demonstrated to be non‐selective for the targeted species. Reducing codend circumference to 100 meshes and increasing the size of mesh to 45 mm both improved selection for eastern king prawns, but the lateral mesh openings were estimated to be insufficient to allow juveniles of the other key species to escape. By contrast, codends made from 35‐ and 41‐mm mesh hung on the bar improved the size selection for eastern king prawns and selected stout whiting, Sillago robusta (Stead) (the smallest commercial‐sized fish) across narrow selection ranges and at 50% sizes of retention (L₅₀s) that were closely correlated to the transverse morphology of fish and the maximum mesh opening. With the exception of a reduction in catches of octopus, Octopus spp., by the 41‐square codend, there were no other impacts on commercial catches by the square‐mesh designs. It was concluded that diamond‐mesh codends are inappropriate for use throughout this multispecies fishery and that a modified design comprising at least 35‐mm mesh hung on the bar is required to minimise the fishing mortality of unwanted sizes of the key target species. The results are discussed in terms of the utility of these types of modifications for closely regulating selection in penaeid‐shrimp trawls.     

Applying forest restoration principles to coral reef rehabilitation

• 1. Forest restoration through silviculture (gardening) programs revives productivity, biodiversity, and stability. As in silviculture approaches, the coral ‘gardening’ strategy is based on a two‐step protocol.
• 2. The first step deals with the establishment of in situ and/or ex situ coral nurseries in which corals are farmed (originating from two types of source material: asexual [ramets, nubbins], and sexual [planula larvae, spat] recruits).
• 3. The second is the reef rehabilitation step, where maricultured colonies are transplanted into degraded sites.
• 4. We compare here the rationale of forest restoration to coral reef ecosystem restoration by evaluating major key criteria. As in silviculture programs, a sustainable mariculture operation that focuses on the prime structural component of the reef (‘gardening’ with corals) may promote the persistence of threatened coral populations, as well as that of other reef taxa, thus maintaining genetic diversity. In chronically degrading reef sites this may facilitate a halt in biodiversity depletion.
• 5. Within the current theoretical framework of ecosystem restoration, the recovery of biodiversity indices is considered a core element since a rich species diversity provides higher ecosystem resilience to disturbances.
• 6. The gardening measure may also be implemented worldwide, eliminating the need to extract existing colonies for transplantation operations. At degraded reef sites, the coral gardening strategy can assist in managing human and non‐human stakeholders' requirements as is done in forest management.

Copyright © 2003 John Wiley & Sons, Ltd.     

Seed production of Charybdis feriatus (Linnaeus)

Some aspects of the reproductive biology of Charybdis feriatus (Linnaeus) were investigated to identify suitable techniques for broodstock management and seed production. Likewise, factors such as ablation, water depth and light requirements affecting survival or reproductive performance were tested. Production of megalops in tanks and juveniles in net cages installed in earthen ponds was conducted. Wild‐caught berried females produced a significantly higher number of zoeae per gram body weight (BW) of the female (3300±600) than captive spawners (867±58). Ablated and unablated crabs spawned after a month and ovaries of both had oocytes in all developmental stages after spawning, indicating that ablation was not necessary. Broodstock survived higher when stocked in 1 m‐deep water and kept in dark conditions compared with shallow (0.5 m depth) water or ambient lighting. There were six zoea and one megalopa stage. Megalops were produced (survival of 2–22% in 1 tonne or 23–55% in 3 L tanks) when methods for the mud crab Scylla serrata (Forsskål) were used, but feeding with Artemia started only at the Z4 stage. Survival of megalops after 1 month was higher when stocked in net cages installed in an earthen pond (32–82%) than when reared continuously in land‐based tanks (5–11%).     

Reporting and advising on the effects of fishing

Scientists hold different views about environmental management. These views may drive their interest in the subject and help them to address a wide range of research issues, but they can also affect the ways in which research results are interpreted and reported. Studies that mix science and perspective can compromise public and scientific understanding of fishing effects, as perceived differences in evidence may actually reflect differences in interpretation. To improve the rigour of ‘fishing effects’ science, it would help if the benchmarks used to assess whether fishing effects ‘matter’ were always made explicit. These benchmarks might be the objectives set by the management authorities and/or a series of alternate objectives proposed and stated by the scientist. To demonstrate how the reported significance of fishing effects can depend on objectives, I use a simple model to predict the response of fish populations and communities to fishing. Fishing effects that would be reported as negative in relation to preservation or biodiversity objectives, such as declines in size, abundance and trophic level, occur at lower fishing intensities than those associated with meeting sustainability objectives for target species. When fishing pressure is so high that both conservation and fisheries objectives are not being met, the initial management actions to meet a range of objectives are likely to be compatible (e.g. reduce capacity, support alternate livelihoods).     

宁夏规模养殖场（园区）兽药使用管理现状调研及规范化管理探讨

为了有的放矢地推进兽药使用管理和确保兽用使用安全,对宁夏省规模养殖场（园区）兽药使用管理的技术力量、兽药贮存条件、兽药来源及贮存方式、兽药使用及休药期执行情况等进行了调查分析,表明规范兽药使用管理已具备有利条件,同时探讨了规范兽药使用管理的主要内容和重点措施。