FIELD
REPORT
2013
Amazon Riverboat Exploration—2012 FIELD REPORT
SHARK CONSERVATION IN BELIZE
1
Shark Conservation in Belize
2013 FIELD REPORT
Background Information
LEAD PI: Demian Chapman
REPORT COMPLETED BY: Demian Chapman
PERIOD COVERED BY THIS REPORT: Field Season 2013
DATE REPORT COMPLETED: 2014-06-23 23:52:51
Phone: 1-800-776-0188
Web: earthwatch.org
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To the Earthwatch Volunteers,
First, I would like to thank you very much for continuing to make each season of Earthwatch such a rousing
success. My research group and I had a wonderful time with each group and we hope that you had a great time
as well. The enthusiasm that each and every volunteer brought to the project has really inspired us to keep
fighting for the sharks of the Belize Barrier Reef and beyond. You have all made a big difference. Our 2013 field
season was an unqualified success. First, we have sampled and analyzed nearly 1,000 organisms from
Southwater Caye and Glover’s Reef for stable isotopes. These analyses have provided new insight into the ecology
of sharks and other large reef predators that will soon be published. We have found that Caribbean reef sharks
occupy a similar trophic position to barracuda and large grouper as opposed to occupying a trophic position above
them. This means that Caribbean reef sharks, barracuda and large grouper all assume the role of top predator
in ecosystems like Glover’s Reef. Under these circumstances some of the ecological impact shark population
declines could be mitigated if populations of some of these other species remain intact. Our stable isotope
analyses also suggest that Caribbean reef sharks might prey on stingrays as they get larger, which helps us
interpret some other things we are observing in our population surveys detailed below. In 2013 we maintained our
time-series of shark abundance at Southwater Caye and Glover’s Reef, which will provide new information on the
recovery time of imperiled apex predator populations in heavily fished areas. While maintaining the time-series
using Baited Remote Underwater Video (BRUVs) we have confirmed that there is a strong negative correlation
between reef shark and stingray relative abundance on four reefs subjected to different levels of fishing, but only
in deep habitats. This indicates that rays avoid using deep habitats when there is a higher risk of shark predation.
Since rays have large physical effects on the benthic substrate (bioturbation) and may compete with fishermen for
invertebrate prey species, this is especially exciting because it suggests that reef sharks can indirectly affect
other parts of the reef ecosystem simply by being there. With this new insight we will publish a paper on this topic
and establish a firm foundation for the direction of our research for the next few years. These findings will apply
far beyond Belize and will be used at the forefront of efforts to protect sharks throughout the developing world
through the establishment and enforcement of marine protected areas. All of our volunteers are among the very
best ambassadors for sharks and have made a great contribution to saving them just by coming on the expedition.
Please continue to spread the word about the plight of sharks by sharing your experiences with us to your family
and friends.
All the best,
Sincerely,
Demian D. Chapman
School of Marine and Atmopsheric Sciences, Stony Brook, New York
SECTION ONE: Scientific research achievements
TOP HIGHLIGHT FROM THE PAST SEASON
The most significant achievement of 2013 has been putting everything from year 1 to 3 together and answering our original
questions. First, we have found that Caribbean reef sharks occupy more or less the same trophic level as large grouper and
barracuda and feed across a wide range of habitats at Glover's Reef. Second, we have found evidence that Caribbean reef
shark density influences stingray habitat use: specifically, rays tend to occupy shallower habitats when sharks are locally
abundant. Together, these two findings will help us predict the effects of overfishing sharks on coral reef ecosystems. Our
other major finding is to confirm that large, well enforced marine reserves harbor stable Caribbean reef shark populations
over the study period, which provides strong evidence that this approach can be useful for protecting this and similar
species.
REPORTING AGAINST RESEARCH OBJECTIVES
Figure 1. Proportion of BRUVs with at least one Caribbean reef shark observed at Glover’s Reef, Caye Caulker, Turneffe
and Southwater Caye. Each bar represents one year from 2009-13. * indicates BRUV data collected by not processed in
2013.
Our first research objective was to use baited remote underwater videos or "BRUVs" to test the hypothesis that marine
reserves harbor robust, stable shark populations when compared to fished reefs. We have demonstrated this is the case by
sampling two reserves (Glover's Reef and Caye Caulker) and two comparable fished sites (Turneffe atoll and Southwater
Caye) multiple times since 2009. Our results show that that a higher fraction of reserve BRUVs "capture" sharks than the
fished site BRUVs and this pattern is consistent over time (Figure 1). Our sampling now continues to see if shark
populations in Southwater Caye, originally a fished site, recover now that it is a reserve and, if so, estimate the timeline
for recovery of an exploited reef shark population after reserve establishment. Our BRUV data also enabled us to
investigate the ecological impact of sharks in Belize. We found a strong negative correlation between reef shark and
stingray relative abundance on BRUVs set in deeper forereef habitat in our sampling, however there was no difference in
stingray abundance in the four sites when sampling shallow flats habitat. We interpret this pattern to indicate that rays
mediate their behavior or habitat use on reefs where sharks are present by avoiding the deep forereef where they are
vulnerable to attack and instead tend to remain in shallow, safe habitat.
Our second research objective was to better characterize the trophic structure of coral reef ecosystems, especially with
regard to large predators such as sharks, grouper and barracuda. There is some debate as to whether large reef sharks
primarily prey on other large piscivores ("fishing-eating") predators such as grouper and barracuda and have strong
influence on their abundance. The alternative is that reef sharks prey on similar prey as the other large predatory fish and
these species may therefore function more as a collective and potentially competitive unit. This distinction is very
important for developing predictive coral reef ecosystem models.
Table 1. Number of tissue samples collected from sharks, rays and reef fish 2009-2013.
We have met this objective by sampling muscle tissue from 20+ individuals a wide variety of reef organisms and conducting
stable isotope analysis to assess their relative trophic level and foraging habits. We have sampled ~560 individuals of 30
species from Glover's Reef and ~ 400 from South Water since the 2011 field season (Table 1) and have processed almost all
of them. Nitrogen isotopes reflect the trophic position of an organism because their tissues accumulate higher
concentrations of the heavy nitrogen isotope than their prey, resulting in predictable enrichment of nitrogen in the tissues
of higher trophic level species. Carbon isotopes, on the other hand, are relatively consistent as they move up the food
web. Different primary producers, however, have different carbon heavy to light isotope ratios which provides a chemical
tag with which to trace the contribution of different sources of primary production (i.e., different habitats) to predator
diets.
Figure 2. Preliminary isotope bi-plot for sharks and reef fish at Glover’s Reef, Belize.
Figure 3. Linear regression of Caribbean reef shark total length and carbon isotopes.
We have found that large groupers (mainly black grouper, Mycteroperca bonaci) and great barracuda (Sphyraena
barracuda) constitute the top predator guild together with Caribbean reef sharks at Glover's Reef. Stable isotope analysis
provides no evidence that Caribbean reef sharks occupy a higher trophic level than other predators. This can been seen in
Figure 2, showing that the nitrogen in the tissues of all of these species are enriched at a similar level. The carbon profiles
of Caribbean reef sharks also reveal that they feed across a wide variety of habitats and that larger individuals differ from
smaller sharks in where they feed (they likely feed in the same places as stingrays and possibly on stingrays themselves,
Figure 3).
SECTION TWO: Impacts
PARTNERSHIPS
In 2013 we collaborated with the Wildlife Conservation Society (WCS), specifically Janet Gibson and Robin Coleman, and
the University of Belize. The nature of the collaboration has been to provide field experience and training in BRUV
technology so that they can use our data and equipment to study marine reserve effects on commericially important food
fish from the Family Lutjanidae (snapper).
CONTRIBUTIONS TO CONVENTIONS, AGENDAS, POLICIES, MANAGEMENT PLANS
• International
PI Chapman recently worked with the Bahamas National Trust and the Fiji Department of Fisheries in their efforts to
improve shark conservation in these nations. Raw BRUV footage and collated BRUV data from Belize was used to
illustrate large differences in shark abundance between fished and reserve reefs to policymakers and stakeholders.
The rarity of sharks on fished reefsresonated with the communities given the local economic benefits of shark
ecotourism in these countries. This outreach helped inspire national decisions to formally protect sharks in the
Bahamas. Dr. Chapman's work has also been central in listing five shark species of concern on Appendix II of the
Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
• National or regional
The PIs have established partnerships with local NGOs, education centers and management agencies in Belize,
including the Wildlife Conservation Society (WCS), the Association of Marine Protected Area Management Organization
(APAMO), the University of Belize and the Belize Department of Fisheries. As part of an ongoing effort to improve the
sustainability of fisheries in Belize, PI Babcock collaborates on stock assessments with the Fisheries Department. At
the request of the Fisheries Administrator PI Chapman has set up a monitoring program to establish the species and
size composition of the shark fishery in Belize, with the goal of developing better shark fishery management practices.
Figure 4. Species compostion of anal fins collected from shark fishermen from Belize in 2013.
This most recently involved DNA testing 802 tissue samples they collected to determine the species composition of the
shark fishery (Figure 4). This culminated in a one day workshop with Fisheries personnel and border control held on March
18, 2014 that developed a strategy to make the fishery sustainable and implement new international trade restrictions on
certain species.
• Local
Norlan Lamb and Asbert Miranda are both active in their local community and have recently formed their own NGO to
help promote sustainable fisheries for their local communities.
DEVELOPING ENVIRONMENTAL LEADERS
We hosted our first teen fellowship (IGNITE) trip in our Earthwatch 2013 field season. We trained them in a variety of field
techniques in hopes that this experience will foster their interest in global shark conservation as the next generation of
possible marine scientists and resource managers. Their understanding of environmental concerns at both the community
and global levels was enhanced. We also hosted fisheries officers from the Belize Department of Fisheries for a shark
identification field training exercise at Glover's Reef in January 2013. These officers are now leading the efforts in
monitoring and regulating shark fishing in Belize.
ACTIONS OR ACTIVITIES THAT ENHANCE NATURAL AND/OR SOCIAL CAPITAL
In 2014 we will begin an invasive lionfish research and eradication program as part of our Earthwatch teams in addition to
conducting local surveys of conch (Strombus gigas), a key fishery species in Belize.
CONSERVATION OF TAXA
The proposed project will contribute conservation-relevant data for a large number of species listed under the
International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. This includes species where our
data could change the listing, such as the Caribbean reef shark (listed as "Near Threatened", but assessors indicate
"Vulnerable" may be more appropriate after more research) and nurse shark (listed as "Data Deficient"). We will also gather
data on the ecology, local abundance or population trends of several species that are listed as "Endangered", including
great hammerhead sharks and Nassau grouper. Since the inception of this research the great hammerhead has been listed
on Appendix II of the Convention on International Trade in Endangered Species (CITES), our study provided data which
helped in these listing efforts. Additionally, Dr. Chapman has already contributed data and expertise to the Belize National
Plan of Action for Sharks, which is part of a global effort by the United Nations to improve shark management. We are
primarily contributing information on the biology, status and population trends of the following species: Caribbean reef
shark, Carcharhinus perezi (Near Threatened) Nassau grouper, Ephinephalus striatus (Endangered) Black grouper,
Mycteroperca bonaci (Near Threatened). In 2012, we expanded to include the following species by spending more time at
Southwater Caye, a place where these species are more common than at Glover's Reef: Great hammerhead shark, Sphyrna
mokarran (Endangered) Scalloped hammerhead shark,(Endangered).
CONSERVATION OF HABITATS
We are surveying predatory fish abundance in several locations in Belize, providing key information necessary to manage
tropical nearshore ecosystems (coral reefs, seagrass and lagoon communities). This information will be synthesized and
provided to the primary resource managers in Belize, thus contributing to the management of these habitats.
ECOSYSTEM SERVICES
Top predators can have large impacts on the ecosystem by directly controlling density of lower trophic level species or
changing their behavior through intimidation. Our project aims to restore both ecological functions on Belizean coral reefs.
It also aims to build awareness of the importance of these processes.
IMPACTING LOCAL LIVELIHOODS
Two Belizeans are employed full time during the project and derive a significant fraction of their annual income from the
project. Approximately 20 Belizeans derive part of their annual income from our use of the field stations during the
project. Beginning Summer 2014 each team will spend one night in Dangriga, Belize which will bring more revenue into the
local town.
LOCAL COMMUNITY ACTIVITIES
In the town of Dangriga local stakeholders (hotel owners) have asked us to present our research to their guests. The hotel
caters to many local Belizeans which helps to keep them informed on the status of the health of their local reef
ecosystems. We have previously hosted and will continue to host students from the University of Belize to participate in
the data collection and expedition.
DISSEMINATION OF RESEARCH RESULTS
Scientific peer-reviewed publications
Three publicatiions are in preparation.
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