Effects of stocking density on behaviour and roe yield in kelp-fed green sea urchins (Strongylocentrotus droebachiensis) farmed in a custom-made raceway

密度高达500个人m-2，绿色海胆，Strongylocentrotus droebachiensis，是adominant食草动物在浅岩石潮下带栖息地在北方海湾的圣劳伦斯（NGSL）。目前在NGSL的几个地点，完全依靠人工捕捞单个海胆的绿色海胆渔业正在运作。然而，成功是有限的，主要是因为时间短，即在秋季和冬季的几个星期，在此期间，海胆性腺或“卵”（海胆的器官出售给人类消费）必须被收集，以尽量减少数量和质量的变化。这种渔业主要针对海胆放牧前沿，在贫瘠的土地上留下高密度的营养不良的海胆，如果这些海胆在陆基设施中使用正确的设备进行养殖，可以形成可行的商业开发基础。Pêcheries Shipek S.E.C.（PSSEC）是魁北克主要海洋鱼类和贝类商业捕捞的领导者，需要了解定制水道（持续流动海水的水槽系统）的适用性，以快速生产大量绿色海胆卵。在这个项目中，我们将研究海胆放养密度如何影响海胆聚集，喂养，以及跑道中的鱼卵产量，作为第一步，以确定跑道是否可以支持绿色海胆喂养海带的稳定商业鱼卵生产。每周试验将进行12周，在此期间，在跑道的多个部分，海胆和海带将定期拍摄，死亡率，海带消耗量，and degree度of aggregation聚集quantitatively量化from the videos视频.在实验开始和结束时，将对海胆的鱼卵含量（体细胞生殖指数）进行定量，以确定与放养密度和聚集程度的关系。该公司将利用这一新的行业合作产生的信息，研究向鱼贩提供多样化品种的可能性，同时将自己的一部分产品直接出口到区域和全球市场。

With densities of up to 500 individuals m-2, the green sea urchin, Strongylocentrotus droebachiensis, is adominant grazer in shallow rocky subtidal habitats in the northern Gulf of St. Lawrence (NGSL). A green seaurchin fishery entirely dependent on harvesting individual urchins manually is currently in operation at severalsites in the NGSL. However, success is limited mainly because of the small period, i.e. a few weeks in fall andwinter, during which urchin gonad or "roe" (the urchin's organ marketed for human consumption) must becollected to minimize variability in quantity and quality. This fishery mainly targets urchin grazing fronts,leaving in the barrens high densities of undernourished urchins that could form the basis of a viablecommercial exploitation if these urchins were farmed with the right equipment in land-based facilities.Pêcheries Shipek S.E.C. (PSSEC), a leader in commercial harvesting of key marine fish and shellfish species inQuébec, needs knowledge on the suitability of a custom-made raceway (system of troughs with continuouslyrunning seawater) for quick production of high volumes of green sea urchin roe. In this project, we willexamine how urchin stocking density affects urchin aggregation, feeding, and roe yield in the raceway as a firststep to determining if the raceway can support steady commercial roe production in green sea urchins fed kelp.Weekly trials will be carried out over 12 weeks during which urchins and kelp in multiple sections of theraceway will be filmed at regular intervals and mortality, amount of kelp consumed, and degree of aggregationquantified from the videos. Roe content (somatogonadic index) will be quantified from urchins at the onset andend of the experiment to determine relationship to stocking density and degree of aggregation. Informationgenerated from this new industry collaboration will be used by the company to examine the possibility ofdiversifying the range of species it provides to fishmongers, while exporting a part of its own productiondirectly to regional and global urchin roe markets.