《南印度洋渔业管理协议》概况及中国远洋渔业的应对策略

《南印度洋渔业管理协议》于2012年6月21日正式生效。截至目前,澳大利亚、库克群岛、欧盟、法国、日本、韩国、毛里求斯和塞舌尔是《南印度洋渔业管理协议》的缔约方,目前该协议无合作非缔约方。本文主要对该协议产生的背景及过程、生产作业范围、海域主要的生物资源、协议主要目标和基本原则等内容进行解读和分析。目前我国不是该协议的成员国,但基于我国远洋渔业的发展战略及在印度洋的渔业生产现状,应考虑尽快加入该协议,在印度洋公海渔业资源的开发和利用中争取相关权益。

《南印度洋渔业协定》管理措施的新进展及我国的应对策略

印度洋海域是世界渔业的主要作业渔场之一。为管理和养护南印度洋渔业资源,自《南印度洋渔业协定(the Southern Indian Ocean Fisheries Agreement,SIOFA)》生效以来,该组织颁布了16项渔业管理措施,并持续更新。目前,我国鲜有文章对其进行研究。为稳定和拓展我国在南印度洋上的渔业空间,保障我国远洋渔业的权益,密切跟踪南印度洋渔业组织的最新管理动态和履约要求,阐述了组织构架、最新管理措施对我国的影响、目前协定区域的渔情渔况及资源评估状况,为我国适时加入该组织提供参考。研究结果表明,在2019年7月第六次缔约方大会上,SIOFA修订了临时管理底层渔业的养护管理措施,数据收集、报送、验证和交换标准,捕鱼授权和通知养护管理措施,渔业监控养护管理措施4项养护管理措施。新增有关公海登检(high seas boarding and inspection procedures)、降低海鸟兼捕量(the mitigation of seabird bycatch)、底层鲨鱼(management of sharks)、底层鱼种管理(management of demersal stocks)与修正保护区和生态系统工作组工作职责(amendment terms of reference for the PAEWG or new CMM)的5项新养护管理措施。截至目前,该组织设立了Atlantis bank、Coral feature、Fool’s flat feature、Middle of What feature、Walter’s Shoal feature 5个保护区,对金眼鲷(alfonsino)、胸棘鲷(orange roughy)和犬牙鱼(Patagonian toothfish)等底层鱼种初步进行了资源评估,其中,胸棘鲷评估结果为尚未过度捕捞,金眼鲷和犬牙鱼还未完成评估。该渔业组织的管理措施与我国相比较更严谨、更全面,我国作业渔船应当严格遵守该渔业组织的管理要求。目前,该组织还在不断完善相关养护和管理措施,尽早加入该组织才能有助于我国远洋渔业持续、健康、有序地发展,体现国际影响和负责任渔业国家形象。

美、日、英、法对印度洋渔业也“很感兴趣”

据苏联《渔业快报》报道，在联合国粮农组织的主持下，于1971年成立了印度洋渔业委员会，这个委员会将专门“援助”印度洋的渔业发展。

Evaluation of Three Harvest Control Rules for Bigeye Tuna(Thunnus obesus) Fisheries in the Indian Ocean

The stock of Bigeye tuna(Thunnus obesus) in the Indian Ocean supports an important international fishery and is considered to be fully exploited. The responsible management agency, the Indian Ocean Tuna Commission(IOTC), does not have an explicit management decision-making framework in place to prevent over-fishing. In this study, we evaluated three harvest control rules, i) constant fishing mortality(CF), from 0.2 to 0.6, ii) constant catch(CC), from 60000 to 140000 t, and iii) constant escapement(CE), from 0.3 to 0.7. The population dynamics simulated by the operating model was based on the most recent stock assessment using Stock Synthesis version Ⅲ(SS3). Three simulation scenarios(low, medium and high productivity) were designed to cover possible uncertainty in the stock assessment and biological parameters. Performances of three harvest control rules were compared on the basis of three management objectives(over 3, 10 and 25 years): i) the probability of maintaining spawning stock biomass above a level that can sustain maximum sustainable yield(MSY) on average, ii) the probability of achieving average catches between 0.8 MSY and 1.0 MSY, and iii) inter-annual variability in catches. The constant escapement strategy(CE=0.5), constant fishing mortality strategy(F=0.4) and constant catch(CC=80000) were the most rational among the respective management scenarios. It is concluded that the short-term annual catch is suggested at 80000 t, and the potential total allowable catch for a stable yield could be set at 120000 t once the stock had recovered successfully. All the strategies considered in this study to achieve a ‘tolerable' balance between resource conservation and utilization have been based around the management objectives of the IOTC.

Evaluation of FAD-associated purse seine fishery reduction strategies for bigeye tuna (Thunnus obesus) in the Indian Ocean

In the Indian Ocean, bigeye tuna supports one of the most important fisheries in the world. This fishery mainly consists of two components: longline and purse seine fisheries. Evidence of overfishing and stock depletion of bigeye tuna calls for an evaluation of alternative management strategies. Using an age-structured operating model, parameterize dwith the results derived in a recent stock assessment,we evaluated the effectiveness of applying constant fishing mortality (CF) and quasi-constant fishing mortality (QCF) strategies to reduce fishing effort of purse seining with fish aggregating devices (FADs) at different rates. Three different levels of productivity accounted for the uncertainty in our understanding of stock productivity. The study shows that the results of CF and QCF are similar. Average SSB and catchduring simulation years would be higher if fishing mortality of FAD-associated purse seiningwas reduced rapidly. The banning or rapid reduction of purse seining with FAD resulted in a mean catch, and catch in the last simulation year, higher than that of the base case in which no change was made to the purse seine fishery. This could be caused by growth overfishing by purse seine fisheries with FADs according to the per-recruit analysis. These differences would be more obvious when stock productivity was low. Transferring efforts of FAD-associated purse seining to longline fisheries is also not feasible.Our study suggests that changes are necessary to improve the performance of the current management strategy.