Coral Nursery Best Practices

CCMI Workshop Part I: 2 Mar 2015

Why propagate Acropora?• Major reef-builder

• Fast-growing

• Critically endangered (80-90% decline since 1980s)

Acropora fossils show that these species have dominated reefs for millions of years

Building Coral Nurseries

• Minimize negative effects on wild populations by collecting small amounts of tissue from a genetically diverse parent population

• Maximize production within an in-water coral nursery to create a healthy and sustainable source of coral for use in restoration activities

Healthy wild colonies are clipped/fragmented and coral fragments are grown in an underwater nursery. Once the corals grow large enough they are fragmented again to produce more corals. Corals are then outplanted to existing reef areas.

• There is no “one size fits all” approach that applies to all locations, regions and environmental conditions.

• Propagation and restoration activities should be adaptive and flexible to account for variability in local environments– water conditions (depth, wave energy,

turbidity)– habitat suitability– competition– likelihood of human impacts

Nursery Site Selection

• Existing Wild Populations• Depth• Water Motion• Bottom Type• Size of Area• Adjacent Habitat• Competitors• Human Activities/Impacts• Accessibility• # Nurseries• Permitting

** Pilot/Test Deployments

Types of Nurseries

Fixed to Bottom Nurseries- Frames and Platforms

Fixed to Bottom Nurseries- Important Considerations

• Fragment orientation (vertical vs. horizontal)• Space between nursery structures (divers and cleaning)• Nursery expansion• Nursery organization (separation of generations)• Spacing of fragments (individual tracking and avoid

fusion)- leave space on blocks or frames for fragmentation

• Mesh size for frames- 10 to 15 cm ideal• Materials should be easily moved• Good for high traffic (boating and fishing) areas due to

low profile• Location in relation to nearby reef habitat (herbivores vs.

predators; human impacts)

Mid-water floating nurseries- Lines and Trees

Line and Tree Nurseries- Important Considerations

• Space between structures (wave motion and storms)

• Nursery expansion (separation of generations)• Fragment spacing • Mid-water floating nurseries promote rapid growth

and branching of small fragments

• Faster growth may affect skeletal density resulting in fragile fragments prone to breakage (may require securing corals to a platform or frame before outplanting to increase skeletal density

• Floating nurseries protect corals from predation

• Floating nurseries may not be suitable in areas with intense boating and fishing activities that may result in line entanglement and breakage

Supplies needed for installing nurseries

• Line (polypropylene, fishing line), frames (wire mesh- resin coated), and/or blocks

• Rebar/cement/sand screws for anchoring• Hammers• Pliers or snips• Cable ties• Epoxy• Buoys• Tags for identification

Decide where to collect corals• Existing Wild Populations: Knowledge of natural healthy populations

of Acropora within a reasonable proximity to the nursery site will be critical in guiding collection efforts. The overall size (at least 45 cm diameter) and health (no visible signs of disease) of potential donor colonies are important and affect both the health of collected fragments and the donor colony.

• Size of the Area: The geographic area should be large enough to ensure genetic diversity between collected corals while minimizing transport time between the collection site and the nursery.

• Proximity to Nursery Site: If monitoring of wild donor colonies is required, close proximity to the nursery site may be an important logistical and financial consideration.

• Number of Sites: Collecting from a variety of areas or habitats may further increase the likelihood of genetic variation within the nursery as well as the ability of nursery-reared corals to adapt to different habitats and environmental conditions.

• Permitting

Fragmented Branches

Control

Parent Colony Recovery

September 7, 2012 February 28, 2013

Growth Rates By Genotype

Tracking colony genotypes is imperative; genotype impacts colony performance and is one of the most important factors to consider with regard to outplanting

• Tools: ruler, clips/bone cutters/pliers, mesh/plastic bags

• Transport: always place in shade to maintain temp; place in cooler/rubbermaid container with seawater (<4 hrs)

• Water temp: October-May• Fragment size: 5cm (branching)• Corals of opportunity/at risk• Donor colony/fragment tracking (unique

identifier)– Colony size– # branches– % live tissue

***it’s a good idea to check on newfragments within a week of fragmentation/outplanting

Installing Fragments in Nursery• Keep genotypes together or ensure proper tagging for

identification

• Make sure substrate is clean of fouling

organisms

• Properly secure fragments to nursery

structure (epoxy, cable ties, line)

• Remove any predators

• Take initial measurements/photos

Nursery Maintenance• removal of algae and other fouling organisms (tunicates,

sponges, hydroids, etc.) by hand or with small wire brushes

• active propagation and fragmentation of corals to increase nursery stock available for outplanting

• removal of coral predators such as snails, fireworms and damselfish

• stabilization of broken or damaged fragments using epoxy, cable ties or other mechanisms

• repairing of damaged modules, line materials, attachment materials and/or anchoring materials

• isolation or removal or treatment of diseased corals

• construction or installation of materials for expansion and propagation of nursery corals

Regular Maintenance and Monitoring

• Nursery colonies must be monitored and maintained monthly

• A typical monitoring visit with measurements of ~60 corals requires ~60 minutes for 2 trained divers at 25 feet

• A typical maintenance visit with a full cleaning for ~250 corals requires ~75 minutes for 2 trained divers at 25 feet

• Dive times will increase as colonies grow!

Tools for nursery maintenance• Wire/nylon brushes• Epoxy• Cable ties• Snips/pliers• ID Tags• Clipboard/underwater paper• Rulers/calipers• Pencils• Camera• Extra line/buoys/rebar• Gloves

***always be prepared to rescue fragments or repair broken nursery structures

Emergency SituationsEmergency situations require an immediate investment of time, energy, and money:

•Hurricanes

•Disease outbreaks

•Predator outbreaks

•Algal blooms

•Ship groundings

•Nursery structural failures

Monitoring Parameters:1) Growth Measurements • Initial measurement when fragment is brought into the

nursery (total linear extension= sum of all branches) • Fragmentation measurement: live tissue of “parent” colony

plus live tissue of fragment removed = total production of the colony over time

2) Number of branches (any tissue ›1 cm)3) Number of apicals 4) Maximum branch width – width at base of colony or

fragment 5) Condition – disease, predation, bleaching, algal and other

overgrowth, breakage, tissue loss (%) 6) Mortality – # of fragments or colonies with complete tissue

loss 7) Attachment or stabilization of fragments or colonies –

e.g., loose or cemented to platform, loose or intact cable ties

8) Water quality – temperature and light (Hobo loggers) 9) Photographs

Measuring Total Linear Extension

Average Little Cayman Growth Rates

September TLE = 594 cm, March TLE = 2190 cm

Growth can quickly get out of hand if not managed consistently!

Initial 8 months

1 month after fragmentationevent

8 months

Before Fragging After Fragging

Pro

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35 *p<0.001

Lirman et al.,2014

Lohr et al., in press