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GLASS SPONGE REEFS | Page 116

Glass Sponge Reefs: a new opportunity for

conservation research

AUTHORJeff Marliave, Ph.D., Senior Research Scientist,

Howe Sound Research Group, Coastal Ocean

Research Institute, Vancouver Aquarium

Marine Science Center

REVIEWERLena Clayton, B.Sc., Researcher, Marine Life

Sanctuaries Society

What’s happening with glass sponge reefs?In 2015, Fisheries and Oceans Canada (DFO) closed bottom contact fishing

(i.e., all commercial and recreational bottom contact fishing activities for

prawn, shrimp, crab and groundfish, including halibut, were prohibited) at

nine glass sponge reefs in the Strait of Georgia, including reefs surround-

ing Passage Island at the entrance to Howe Sound, and at Defence Islands

northeast of Anvil Island.1 During the process leading to those closures, cit-

izen scientists Glen Dennison and Lena Clayton were actively using a new

method of drop-camera drift transects to identify locations of glass sponge

reefs in Howe Sound (Figure 1). These newly identified Howe Sound sponge

reefs were not considered during that earlier federal process, so they remain

unprotected, with the exception of the Passage Island sponge reefs.

Photo: Adam Taylor

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GLASS SPONGE REEFS | Page 117

Therefore, citizen scientist divers, dive industry rep-

resentatives (guides, instructors) and the Vancouver

Aquarium’s Howe Sound divers met in May 2015 to

discuss approaches to protecting these Howe Sound

sponge reefs. In an about-face on previous secrecy

about reef locations in order to protect sponges from

accidental anchor damage, it was decided to go public

and invite citizen science divers on the reefs to gain

public awareness. With a grant from Mountain Equip-

ment Co-op (MEC), the Vancouver Aquarium Marine

Science Centre developed a web page2 showing citizen

science divers how to locate and photograph or video-

tape various bar-coded stakes around the periphery of

the inshore Defence Island bioherm, then submit im-

ages of the sponges together with these location iden-

tifier stakes, in order to allow monitoring of sponge

growth and health over time at this site.

In late May, the annual prawn fishing season took

place, with many observations of fishing on Howe

Sound glass sponge reefs noted by conservationists.

The fishery closed earlier than planned in 2016 owing

to low catch rates. The greatest human conflict with

glass sponge reefs relates to fishing gear damage to

the reefs,3 whether from downrigger contact, bottom

trawling or prawn trap contact, and has been the basis

for almost all the negotiated closures with fishing

sectors for the sake of sponge reef protection.

Is there a particular importance or connection to First Nations? The Defence Islands are sacred to the Squamish Na-

tion, and the Squamish Nation has indicated interest

in seeing conservation of the glass sponge reefs off the

eastern Defence Island.

Photomural of offshore Defence bioherm at 100 feet depth. Eight photos taken by Jeff Marliave in August of 2004 and merged using Photoshop.

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Figure 1. Pink dots indicate glass sponge reef locations in Howe Sound determined by drifting drop-camera method

of Glen Dennison and Lena Clayton (personal communication). The four southern-most reefs are located inside a

DFO closure implemented in 2015. The green shading represents the approximate area of Squamish River and Fraser

River outflows in Howe Sound.

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Why is it important? Glass sponge reefs (also called bioherms) were

thought to have gone extinct thousands of years ago4

when they were discovered off the Canadian contin-

ental shelf in the mid-1980s.5 Howe Sound is the only

known location where these glass sponge reefs are

shallow enough to be studied by scuba divers using

compressed air, making them uniquely accessible to

the diving community. Cloud sponge is a common

name for Aphrocallistes vastus, the main reef-forming

glass sponge species in Howe Sound. The cloud name

comes from its appearance.

These glass sponge reefs provide refuge for rockfish

broodstock,6,7 and in Howe Sound the redstripe rock-

fish is a species almost exclusively associated with

these reefs. Spot prawns aggregate around the sponge

reefs, and for that reason the conflict with prawn

trapping activity arises.

What is the current state?“Local knowledge” about cloud sponges differs de-

pending on who you talk to. Fishermen have long said

of cloud sponges, “oh, yeah, that’s sea cabbage, and

it grows back the next winter.” In contrast, divers

had the lore that cloud sponges are hundreds of years

old and never grow back if damaged. The truth is that

there appears to be a tendency for individual spon-

ges to grow at varying rates during different climate

cycles. Deterioration has been observed during the

buildup of El Niños (warm coastal winters) and rapid

episodic growth was observed in some sponges during

La Niña cycles (cooler winters). In 2015, the first proof

of fragment healing and reattachment in cloud spon-

ges was published;8 notably, healing took place during

La Niña weather.

Mechanical damage to sponge reefs in Howe Sound has

been documented in the video transects of Glen Den-

nison.9 The prawn fishery has focused on fishing near

these reefs because of the high densities of prawns

that accumulate around the periphery of the reefs.

Whereas the Pacific cod trawl fishery in the Strait of

Georgia eliminated large areas of glass sponge reef on

Halibut and McCall Banks, the prawn trap fishery has

caused more localized damage, which may experience

healing and recovery during favourable climate cycles.

Monitoring is needed to determine the extent to which

sponge reefs can heal damage caused by climate cycles

or mechanical damage by humans. The dive volun-

teers posting on the Aquarium website for the bar code

marked areas at the inshore Defence Island location

have already documented that necrosis of a head of

cloud sponge can occur within several months.10

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What’s being done?In October 2016, seven organizations11 submitted a

proposal to Fisheries and Oceans Canada asking for

protection of the glass sponge reefs in Howe Sound.

The Regional Director General for the Pacific Region

responded suggesting that the detailed information

provided on the Howe Sound Sponge Reefs would feed

directly into the marine conservation target strategy

of establishing new effective area-based conservation

measures, such as closing fisheries in waters that are

home to sensitive sponges and corals.

Diving representatives approached BC Parks to discuss

possible expansion of Halkett Bay Marine Provincial

Park on Gambier Island, to include the Halkett pin-

nacle sponge reef. On May 26, 2016, the B.C. Minister

of Environment, Mary Polak, announced the expan-

sion of Halkett Bay Marine Park to include the sponge

reef. Future plans are for funding a safe, permanent

boat moorage for divers’ access to that sponge reef.

Citizen science will be enhanced owing to the access-

ibility of this reef at Halkett Point to commercial dive

charters out of Horseshoe Bay.

On March 23, 2016, Canadian Parks and Wilderness

Society (CPAWS) hosted an evening at Science World

on glass sponge reefs, which included discussion of

the Strait of Georgia and Howe Sound reefs. At the

Salish Sea Ecosystem Conference in Vancouver in

April 2016, there were four presentations on the glass

sponge reefs of Howe Sound, covering various aspects

of the biology, ecology and conservation of these reefs.

Between these March and April meetings and the May

announcement of inclusion of the sponge reef near

Halkett Point inside the new boundaries of Halkett

Marine Park, there has been favourable publicity of

these reefs. On May 31, the David Suzuki Foundation

and Vancouver Aquarium hosted a public meeting at

Kay Meek Centre featuring Howe Sound videos, in-

cluding a sponge reef video by Roy Mulder.

A new federal process for protection of Howe Sound

glass sponge reefs under the federal Pacific Region

Cold-Water Coral and Sponge Conservation Strategy,12

which was released in 2011, is being urged for Howe

Sound. Requests are now being promulgated.

Divers need to exercise caution to avoid breaking

sponges by contact with fins or hands, so a new Pro-

fessional Association of Diving Instructors (PADI)

course has been developed to teach safe diving prac-

tice around sponge reefs.

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Glass sponge reef home to juvenile rockfish. (Photo: Adam Taylor)

What can you do?

Individual and Organization Actions:• Contribute to citizen science projects in order to monitor glass sponge growth at the inshore Defence Island

sponge reef.

• Report illegal fishing and trapping to DFO within sponge closure areas.

• Take the PADI course developed to teach safe diving practice around sponge reefs before diving around sponge reefs.

• Familiarize yourself and others with locations of sponge reefs throughout Howe Sound, specifically if bottom contact fishing or mooring your vessel.

Government Actions and Policy:• Encourage local education and awareness of the importance of sponge reefs, and the risks they face.

• Advertise the uniqueness of the opportunity to dive a sponge reef using compressed air in Howe Sound.

• Support local citizen science projects, and formal studies aimed at understanding and monitoring glass sponge reefs.

• Install a safe and permanent moorage for dive boats at glass sponge reef sites.

• Implement full protection of glass sponge reefs throughout all of Howe Sound.

• Restrict bottom contact fishing throughout all glass sponge reefs in Howe Sound.

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ResourcesDrop camera and other videos of sponge reefs in Howe Soundmlssbc.com/2013/04/27/mlss-collaborates-with-experts-from-vancouver-aquarium/

Footnotes1 http://www.pac.dfo-mpo.gc.ca/oceans/protection/sponge_reef-

recif_eponge-eng.html

2 http://www.vanaqua.org/act/research/howe-sound-group/sponges

3 Kahn, A.S., L.J. Vehring, R.R. Brown, and S.P. Leys. 2016. Dynamic

change, recruitment and resilience in reef-forming glass sponges.

Journal of the Marine Biological Association of the United Kingdom.

96 (2): 429-436.

4 Krautter, M., K.W. Conway, J.V. Barrie and M. Neuweiler. 2001.

Discovery of a “living dinosaur”: globally unique modern

hexactinellid sponge reefs off British Columbia, Canada. Facies. 44:

265-282.

5 Conway, K.W., J.V. Barrie, W.C. Austin, and J.L. Luternauer. 1991.

Holocene sponge bioherms on the western Canadian continental

shelf. Continental shelf research. 11: 771-790

6 Marliave, J.B., K.W. Conway, D.M. Gibbs, A. Lamb and C. Gibbs.

2009. Biodiversity and rockfish recruitment in sponge gardens and

bioherms of southern British Columbia, Canada. Marine Biology. 156:

2247-2254

7 Cook, S.E. 2005. Ecology of the hexactinellid sponge reefs on

the western Canadian continental shelf. MSc thesis, University of

Victoria, Canada.

8 Marliave, J. 2015. Cloud Sponge, Aphrocallistes vastus (Porifera:

Hexactinellida), fragment healing and reattachment. Canadian Field-

Naturalist. 129(4):399-402.

9 For examples, see Mulder, R. “Sponge Damage.” Video, June 1, 2015.

Accessed Sept 19, 2016. https://mlssbc.com/2015/06/08/defence-

island-bioherm-dive-may-31-2015/ and “MLSS Discovers Massive

Sponge Bioherm in Howe Sound.” Oct 7, 2014. Accessed Sept 19, 2016.

https://mlssbc.com/2014/10/07/mlss-discovers-massive-sponge-

bioherm-in-howe-sound/

10 Vancouver Aquarium. “Diving Sponge Reefs and Gardens. Accessed

Sept 19, 2016. http://www.vanaqua.org/act/research/howe-sound-

group/sponges

11 Canadian Parks and Wilderness Society, Marine Life Sanctuaries

Society, Canadian Marine Environment Protection Society, David

Suzuki Foundation, Future of Howe Sound Society, Sunshine Coast

Conservation Association, and the Vancouver Aquarium Marine

Science Centre.

12 http://www.pac.dfo-mpo.gc.ca/oceans/protection/docs/cscs-pcce-

eng.pdf