Study

Manipulating artificial habitats to benefit seahorses in Sydney Harbour, Australia

  • Published source details Hellyer C.B., Harasti D. & Poore A.G.B. (2011) Manipulating artificial habitats to benefit seahorses in Sydney Harbour, Australia. Aquatic Conservation: Marine and Freshwater Ecosystems, 21, 582-589.

Actions

This study is summarised as evidence for the following.

Action Category

Create short flexible habitats (1–50 mm) on subtidal artificial structures

Action Link
Biodiversity of Marine Artificial Structures

Create long flexible habitats (>50 mm) on subtidal artificial structures

Action Link
Biodiversity of Marine Artificial Structures
  1. Create short flexible habitats (1–50 mm) on subtidal artificial structures

    A randomized, controlled study in 2008 on two subtidal swimming-enclosure nets in Sydney Harbour estuary, Australia (Hellyer et al. 2011) found that creating short flexible habitats (frayed-netting) on enclosure-net panels had mixed effects on seahorse Hippocampus whitei and mobile invertebrate abundances, depending on the survey week and invertebrate species group. Over two months, net panels with frayed-netting had higher seahorse abundance (1–3 individuals/panel) than panels without flexible habitats (0–1/panel) during six of seven surveys, but similar abundance during the other survey (frayed-netting: 1/panel; without: 0/panel). Mobile invertebrate abundances on panels with and without flexible habitats varied depending on the species group and survey week (see paper for results). Short flexible habitats were created on polyethylene rope swimming-enclosure nets (100 mm mesh size) in March 2008 by attaching clumps of frayed nylon netting (50 mm length) at knot intersections (‘frayed-netting’). Three net panels (length: 0.3 m, height: 1 m) with frayed-netting and three panels without were randomly arranged along each of two enclosure nets (depth not reported). In May 2008, sixty-three seahorses were released onto the nets. Seahorses were counted on panels with and without flexible habitats over two months and mobile invertebrates (seahorse prey) were surveyed using a suction-pump over three months.

    (Summarised by: Ally Evans)

  2. Create long flexible habitats (>50 mm) on subtidal artificial structures

    A randomized, controlled study in 2008 on two subtidal swimming-enclosure nets in Sydney Harbour estuary, Australia (Hellyer et al. 2011) found that creating long flexible habitats (double-netting) on enclosure-net panels had mixed effects on seahorse Hippocampus whitei and mobile invertebrate abundances, depending on the survey week and invertebrate species group. Over two months, net panels with double-netting had higher seahorse abundance (1/panel) than panels without (0/panel) during two of seven surveys, but similar abundance in the other five (both 0–1/panel). Mobile invertebrate abundances on panels with and without double-netting varied depending on the species group and survey week (see paper for results). Long flexible habitats were created on polyethylene rope swimming-enclosure nets (100 mm mesh size) in March 2008 by attaching a second layer of enclosure netting (‘double-netting’). Three net panels (length: 0.3 m, height: 1 m) with double-netting and three panels without were randomly arranged along each of two enclosure nets (depth not reported). In May 2008, sixty-three seahorses were released onto the nets. Seahorses were counted on panels with and without flexible habitats over two months and mobile invertebrates (seahorse prey) were surveyed using a suction-pump over three months.

    (Summarised by: Ally Evans)

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