Short term impact of artisanal dredges in a Patagonian mussel fishery: comparisons with commercial diving and control sites.

Published source details Narvarte M., González R., Medina A., Avaca M.S., Ginsberg S. & Aliotta S. (2012) Short term impact of artisanal dredges in a Patagonian mussel fishery: comparisons with commercial diving and control sites.. Marine Environmental Research, 73, 53-61.
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This study is summarised as evidence for the following.

	Action	Category
	Hand harvest instead of using a dredge Action Link

Hand harvest instead of using a dredge

A replicated, controlled study in 2007 on a mussel bed in the San Matías Gulf, South Atlantic Ocean, Argentina (Navarte et al. 2012 - same experimental set-up as Navarte et al. 2011) found that hand-harvesting mussels caught a similar community composition of unwanted catch, and damaged similar numbers of unwanted sea urchins or brittle stars, compared to standard artisanal dredges. The percentages of total sea urchins Arbacia dufresnei and brittle stars Ophioploccus januarii that were damaged (lightly or severely) were similar by hand-harvesting (sea urchins: 67%; brittle stars: 65%) and dredging (sea urchins: 76%, brittle stars: 75%). Nineteen tows (5 min duration) were conducted in May 2007 on the mussel bed at 14–20 m depth with a standard artisanal dredge (1.6 m mouth width, 80 mm net bag mesh size). Four 40 kg commercial bags of catch hand-harvested by divers in the same area were obtained for comparison. All species were sorted (mussels; unwanted catch), counted, weighed and identified. Average proportions of mussels and unwanted catch (mostly invertebrates) were estimated for each sample. Apart from mussels, sea urchins and brittle stars dominated all samples, and were placed into damage categories: undamaged, lightly damaged or severely damaged (combined under ‘damaged’).

(Summarised by: Anaëlle Lemasson)