Trophic look at soft-bottom communities — short-term effects of trawling cessation on benthos
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Published source details
Dannheim J., Brey T., Schröder A., Mintenbeck K., Knust R. & Arntz W.E. (2014) Trophic look at soft-bottom communities — short-term effects of trawling cessation on benthos. Journal of Sea Research, 85, 18-28.
Published source details Dannheim J., Brey T., Schröder A., Mintenbeck K., Knust R. & Arntz W.E. (2014) Trophic look at soft-bottom communities — short-term effects of trawling cessation on benthos. Journal of Sea Research, 85, 18-28.
Actions
This study is summarised as evidence for the following.
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Cease or prohibit shipping Action Link |
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Cease or prohibit all types of fishing Action Link |
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Cease or prohibit shipping
A before-after, site comparison study in 2003–2004 in areas of soft seabed sediment in the German Bight, southern North Sea, Germany (Dannheim et al. 2014) found that, during the 12–14 months after closing an area to shipping, community energy flow (related to community structure) at sites within the closed area did not change, but it increased in nearby open sites where shipping occurred. Before shipping closure, community energy flow was similar in the closed (80 kJ/m2) and open sites (66 kJ/m2). After 12–14 months, community energy flow in the closed sites was similar to before (69 kJ/m2), but lower than at open sites where energy flow had increased over time (92 kJ/m2). After 12 months, species-level energy flow was higher in closed areas compared to open areas for 10 of 70 species, and lower for 7 of 70 species. In July 2003 a pilot windfarm platform was constructed, and the surrounding area (500 m radius) closed to all shipping (including fishing vessels). Invertebrates were surveyed at 10 sites inside the windfarm area and 10–18 outside (9 km away) before construction (March–August), and 12–14 months after exclusion (July–October 2004). Invertebrates were collected using a sediment grab (0.1 m2) and a beam trawl at 28 m depth. All were identified, counted, weighed, and their biomass converted to energy values (kilo Joule) using conversion factors. Energy flow was used to compare communities.
(Summarised by: Anaëlle Lemasson & Laura Pettit)
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Cease or prohibit all types of fishing
A before-after, site comparison study in 2003–2004 in areas of soft seabed sediment in the German Bight, southern North Sea, Germany (Dannheim et al. 2014) found that, during the 12–14 months after closing an area to all fishing, community structure (measured as energy flow) at sites within the closed area did not change, but increased in nearby open sites where fishing occurred. Before fishery closure, community energy flow was similar in the closed (80 kJ/m2) and open sites (66 kJ/m2). After 12–14 months, community energy flow in the closed sites was similar to before (69 kJ/m2), but lower than at open sites where energy flow had increased over time (92 kJ/m2). After 12 months, species-level energy flow was higher in closed areas compared to open areas for 10 of 70 species, and lower for 7 of 70 species. In July 2003 a pilot windfarm platform was constructed, and the surrounding area (500 m radius) closed to all shipping, and as such all fishing. Invertebrates were surveyed at 10 sites inside the windfarm area and 10–18 outside (9 km away) before construction (March–August), and 12–14 months after exclusion (July–October 2004). Invertebrates were collected using a sediment grab (0.1 m2) and a beam trawl at 28 m depth. All were identified, counted, weighed, and their biomass converted to energy values (kJ) using conversion factors. Energy flow was used to compare communities.
(Summarised by: Anaëlle Lemasson & Laura Pettit)
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