Biological, socio-economic, and administrative opportunities and challenges to moving aquaculture offshore for small French oyster-farming companies
Biological, socio-economic, and administrative opportunities and challenges to moving aquaculture offshore for small French oyster-farming companies
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DOI：
10.1016/j.aquaculture.2020.735045
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发表时间：
2020-05-15
期刊：
影响因子：
4.5
通讯作者：
Gernez, Pierre
中科院分区：
文献类型：
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作者：
Barille, Laurent;Le Bris, Anthony;Gernez, Pierre
牡蛎的生产历来是在潮间带进行的，贝类养殖场已经占据了法国潮间带的大片区域。因此，法国贝类水产养殖在潮间带地区的扩展在空间上是有限的，将生产转移到潮下近海环境被认为是解决这一问题的可能办法。在法国大西洋沿岸寻找新的选址是从年轻农民经营的小牡蛎公司的角度进行的，这些公司对近海双壳类水产养殖的扩张感兴趣，与他们的投资能力相适应。在评估这种离岸生产的可行性时，我们考虑了三个主要问题：(1)双壳类增长潜力和(2)技术可行性和相互冲突的用途，以及(3)行政许可程序的步骤和障碍。与潮间带网箱中的牡蛎相比，近海实验网箱中的牡蛎唾液在重量和长度方面的增长速度都明显快于潮间带网箱，这主要是由于较低的浑浊度和全时摄食能力(即持续浸泡在水中)。然后，结合地球观测数据和双壳类生态生理模型，获得了牡蛎生长潜力的空间分布图，这证实了近海地点比传统养殖牡蛎的潮间带地点总体上具有更好的牡蛎生长潜力，但这在空间上具有很大的变异性。小规模生产者指出，有两个技术因素制约着养殖场的位置：水深必须在5至20米之间，与港口的距离不超过5海里。这些数据与空间多标准评估(SMCE)中各种环境和社会经济制约因素的地图一起被包括在内。旅游交通和渔民底拖网捕捞被发现是另外两个最具限制性的变量。这项研究中开发的基于地理信息系统的SMCE表明，有近400公里(2)高度到非常适合的区域可以利用简单、低成本的底层网箱技术发展近海水产养殖，并可用于在该沿海地区仍在进行的海洋空间规划决策过程中协助贝类产业。然而，对于拥有小公司的农民来说，获得近海许可证所需的行政程序的复杂性被视为比选址、技术可行性和所需投资更大的障碍，为了切实地进行近海种植，这将是至关重要的。这里展示的过程和结果适用于世界各地的其他沿海和近海地点，并可适用于其他物种。
Oyster production has historically taken place in intertidal zones, and shellfish farms already occupy large extents of the French intertidal space. The expansion of French shellfish aquaculture within intertidal areas is therefore spatially limited, and moving production to the subtidal offshore environment is considered to be a possible solution to this problem. Finding new sites along the French Atlantic coast was studied here from the perspective of small oyster companies run by young farmers, who are interested in offshore bivalve aquaculture expansion compatible with their investment capacity. In assessing the feasibility of such offshore production, we considered three main issues: (1) bivalve growth potential and (2) technical feasibility and conflicting uses, both within a spatial framework, as well as (3) the steps and barriers of the administrative licensing process. Oyster spat in an experimental offshore cage showed significantly faster growth, in terms of both weight and length, compared to those in an intertidal cage, mainly due to lower turbidity and full-time feeding capacity (i.e., constant immersion in the water). A combination of Earth Observation data and bivalve ecophysiological modelling was then used to obtain spatial distribution maps of growth potential, which confirmed that offshore sites have better potential for oyster growth than the traditionally oyster-farmed intertidal sites overall, but that this is highly spatially variable. Small-scale producers indicated two technical factors constraining where farms could be located: bathymetry must be between 5 and 20 m and the distance from a harbor no more than five nautical miles. These were included along with maps of various environmental and socio-economic constraints in a Spatial Multi-Criteria Evaluation (SMCE). Touristic traffic and bottom trawling by fisherman were found to be the two other most restrictive variables. The GIS-based SMCE developed in this study showed that there is almost 400 km(2) of highly- to very highly-suitable area within which to develop offshore aquaculture using simple, low-cost bottom-cage techniques, and can be used to assist the shellfish industry in the Marine Spatial Planning decision-making process, still in progress in this coastal area. However, the complexity of the administrative processes necessary to obtain an offshore license is perceived as a stronger barrier by farmers owning small companies than site selection, technical feasibility, and required investments, and will be crucial to address in order to realistically proceed to offshore cultivation. The process demonstrated here, and the results are relevant to other coastal and offshore locations throughout the world and can be adapted for other species.