Restoration Objective:

Evaluate sea urchin removal as a tool for restoration

Site Selection Criteria:

1.7 ha area. Large, discrete area (e.g. bays, bounded by sand or narrow margins) to restrict sea urchin ingress. One of four sites chosen across the Hauraki Gulf with varying environmental conditions. Sea urchins removed in March 2021

Cause Of Decline:

Overfishing of sea urchin predators

Key Reasons For Decline:

Overgrazing

Scientific Paper

Large-scale one-off sea urchin removal promotes rapid kelp recovery in urchin barrens

Restoration ecology.

https://doi.org/10.1111/rec.14060

Organisation:

University of Auckland

Site Observations:

Observation Date

25th Mar 2021 – 24th Mar 2023

Action Summary:

Benthic surveys, canopy cover, kelp density

Lessons Learned:

No reseeding necesssary, many species self seeded

Project Outcomes:

Kelp cover increased in removal areas from 7.7% to 41.7% at 2 years; from 13.5% to 1.7% in control areas Kelp density increased in removal areas from 18.5/m2 to 56.4/m2 at 2 years; from 22.2 to 18.6 in control areas

Area of Restoration (Ha)

1.7 Distance to nearest kelp forest (in metres)

50

Indicator Data:

Indicator:	Ending Value:	Starting Value:
Adult Kelp Density	56.4483 / m²	18.4167 / m²

Observation Date

23rd Mar 2021 – 25th Mar 2023

Action Summary:

Counted lobster at each site

Lessons Learned:

A one off urchin removal can facilitate kelp recovery.

Project Outcomes:

Increased lobster count by 1

Distance to nearest kelp forest (in metres)

50

Indicator Data:

Indicator:	Ending Value:	Starting Value:
Lobster Count	6.0000	5.0000

Observation Date

23rd Mar 2021 – 25th Mar 2023

Action Summary:

Counted snapper in study site

Lessons Learned:

A one off removal of sea urchin can facilitate kelp recovery

Project Outcomes:

Increased kelp but not snapper at this site

Distance to nearest kelp forest (in metres)

50

Indicator Data:

Indicator:	Ending Value:	Starting Value:
Lobster Count	2.0000	4.0000

University of Auckland - Hauturu-o-Toi (Little Barrier)

University of Auckland - Hauturu-o-Toi (Little Barrier)

Restoration Project

University of Auckland - Hauturu-o-Toi (Little Barrier)

Restoration Objective:

Site Selection Criteria:

Cause Of Decline:

Overgrazing

Large-scale one-off sea urchin removal promotes rapid kelp recovery in urchin barrens

Organisation:

University of Auckland

Site Observations:

25th Mar 2021 – 24th Mar 2023

Action Summary:

Lessons Learned:

Project Outcomes:

1.7

50

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Adult Kelp Density

23rd Mar 2021 – 25th Mar 2023

Action Summary:

Lessons Learned:

Project Outcomes:

50

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Lobster Count

23rd Mar 2021 – 25th Mar 2023

Action Summary:

Lessons Learned:

Project Outcomes:

50

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Lobster Count