Study

Field demonstration of a novel towed, area bubble-plume zooplankton (Calanus sp.) harvester

  • Published source details Grimaldo E., Leifer I., Gjøsund S.H., Larsen R.B., Jeuthe H. & Basedow S. (2011) Field demonstration of a novel towed, area bubble-plume zooplankton (Calanus sp.) harvester. Fisheries Research, 107, 147-158.

Actions

This study is summarised as evidence for the following.

Action Category

Use an alternative method to commercially harvest plankton

Action Link
Marine Fish Conservation
  1. Use an alternative method to commercially harvest plankton

    A replicated, controlled study in 2008 of pelagic waters in the Norwegian Sea, Norway (Grimaldo et al. 2011) found that using a bubble-plume harvester in combination with fine-meshed trawls to harvest Calanus spp. zooplankton reduced the amount of unwanted fish larvae and eggs caught compared to using only fine-meshed trawls. Data were not tested for statistical significance. Fewer fish larvae and eggs were caught after the bubble raft was deployed compared to without deployment of the bubble raft, at all depths tested: 25 m (larvae: 70%, eggs: 98% reduction); 15 m (larvae: 96%, eggs: 94% reduction); and 10 m (larvae: 12%, eggs: 92% reduction). Catches of target Calanus spp. were between 30–130% higher in nets after bubble harvesting. In June 2008, a bubble raft was towed at three depths (25, 15, 10 m) by a research vessel. Standard plankton nets (20 cm diameter, 0.5 mm mesh) were towed for 30 min before and after the bubble raft was deployed (number of hauls not reported) and target Calanus spp. and non-target catches compared. The bubble raft produced 0.5–1 mm bubbles from eight perforated hoses towed in parallel. Full details of the bubble raft design are provided in the original paper.

    (Summarised by: Leo Clarke)

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