e-newsletter - Cape Eleuthera Institute

E-NEWSLETTER
SPRING 2015
Ghosts of the Flats: Investigating the
Bonefish Industry in The Bahamas
By Georgie Burruss, Nick Balfour, Zachary
Zuckerman, and Aaron Shultz
Another perfect cast. The fly landed
several feet in front of the bonefish before
the angler pulled the fly away in long,
slow strips. Enticed by the shrimp-like
movements, the fish gulped down the fly
and turned quickly back and forth as he
felt the hook set in his mouth. The battle
had begun.
This struggle between man and fish may
last only moments before the fish shakes
free of the hook, or several minutes if the
angler can skillfully land the fish. Win or
Angler tagging a bonefish with a uniquely numbered spaghetti tag for the
Bahamas Initiative.
lose, anglers from the around the world
travel to The Bahamas just for a chance at that momentary struggle. What’s more, an individual
angler will spend thousands of dollars on lodging, plane tickets, food, transportation, and the
expertise of a local guide - all for the chance at the fish of a lifetime.
All together, the bonefishing industry contributes over $141 million annually to The Bahamas’
economy. The average flyfisherman visiting the Bahamas has been shown to stay longer and
spend more money during their visit than the average tourist. While very profitable, scientists
know relatively little about bonefish life history and movements compared to other sport fish. To
date, the majority of information collected has been on adult bonefish, from observations made
by fisherman, and supported by scientific studies.
Adults are known to spend much of their time in the shallow, near shore environment known
as “flats” that are common throughout The Bahamas. During the day bonefish move up into
mangrove creeks with the incoming tide and back out as it recedes. As they move, they feed on
small fishes and invertebrates - such as crabs, clams, shrimps, and snails - by burying their snouts
in the sediment.
During the new and full moon, bonefish have been documented to migrate en mass into deeper
waters, forming spawning aggregations numbering in the thousands. Around Eleuthera, these
massive schools of fish have been recorded descending greater than 300 feet to release their
eggs in the Exuma Sound. Along with Eleuthera, several other spawning sites have been located
throughout the Bahamas, including Abaco, Grand Bahama Island and Andros. In past studies,
some bonefish have been shown to travel over 50 miles to reach these sites.
Given their significant contribution to the Bahamian economy, knowing the status of the
bonefish population is critical for conservation efforts to be effective, yet not enough data
exists to evaluate their population health. In response, the Bonefish and Tarpon Trust, Fisheries
Conservation Foundation, Cape Eleuthera Institute, and the University of Illinois created the
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Bahamas Initiative to assess bonefish
populations throughout The Bahamas.
Adult bonefish are caught, measured,
and tagged with a uniquely numbered
spaghetti tag. When these fish are caught
again, the recapture location and length
measurement can be compared to the
initial data to determine growth rates
and movements of adult bonefish. This
information can be used to identify critical
habitats – including those used for foraging
and spawning -for bonefish and better
focus conservation and management
efforts. Guides and anglers should be on
the lookout for tagged bonefish and should
report tag numbers, fork length, location,
and date to the Bonefish and Tarpon Trust
(by phone: 321-674-7758 or by email:
[email protected]).
Buddy Pinder, independent guide from Abaco, scouting for bonefish on a
flat. Photo credit to Cindy Pinder.
Bahamian bonefishing guides’ experience and connections in the community have proved
crucial to these research efforts. Buddy Pinder, an independent guide from Abaco with 20 years
of experience, has tagged over 1500 fish since 2009. In an interview, Mr. Pinder noted that the
tagging program has confirmed and further clarified observations about bonefish ecology that he
has made while guiding.
Furthermore, Mr. Pinder cited overfishing as the largest threat to the bonefishing industry and
that increased fishing pressure has started to modify the fish’s behavior. “The fish are there, but
they are just a little bit tougher. They see people every day…. I am part of the problem too, I
am in there fishing every day. We are all part of the problem.” Guides and anglers are able to
reduce their impacts on bonefish through better angling and handling practices, increasing the
survivorship of released fish.
To limit the effects of fishing on the population, Mr. Pinder encourages proper handling
techniques. “The best way I know how people could help bonefish is to handle them properly.
I’ve watched so many people who love to catch bonefish, they like the species, but they have no
idea on proper handling practice.” Proper handling practices are a concern for fishermen and
scientists alike. Fish scales are covered with an external mucous layer that serves as a barrier to
infection and disease, similar to human skin. When handled improperly, large amounts of this
layer can be removed, leaving the fish exposed. Properly handling bonefish by keeping them
in the water and minimizing handling increases their survivorship, reducing the impacts of the
catch-and-release industry on the population. For more information on best handling and angling
practices for bonefish, research conducted by Bonefish and Tarpon Trust, Cape Eleuthera Institute,
Carleton University, and University of Illinois can be found at www.tarbone.org
Guides, such as Mr. Pinder, believe that conservation efforts could be improved with more
knowledge about spawning aggregations as well as critical
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habitats for juvenile bonefish. Ongoing and future scientific research investigating
these and many other knowledge gaps about bonefish will be useful in further
protecting the population. Guides, scientists, and all Bahamians have a vested
interest in conserving this lucrative fishery throughout the Bahamas.
For more information on the Bahamas Initiative and current bonefish research,
please visit www.ceibahamas.org.
Plastics Research Update: You are what you eat...and what
your dinner eats too!
As any angler will tell you, fresh fish is the best
fish (Fig. 1)! Even non-anglers would insist that
grilled wahoo, dockside yellowfin sashimi, or fried
dolphinfish fingers are best when fresh from the sea.
Knowing your fish is wild-caught means there are
no questions about the quality of the fillet, or the
fish’s diet – right?
Each year, between 8-12 million tons of plastic
end up in the world’s oceans, ranging in size from
large pieces of floating trash or small (< 5mm)
microplastics barely visible to the naked eye (Fig. 2).
Some of this debris may result in the entanglement
and death of marine mammals, or can be ingested
by birds, sea turtles, and fish with severe health
consequences. Even more concerning is that plastic
debris acts as a magnet for persistent organic
pollutants (POPs) such as PCBs or DDT – chemicals
known to disrupt hormones or have carcinogenic
effects in humans and animals. Thus, identifying
whether plastic debris is consumed by recreationally
and commercially important fish species should be
of concern to any angler or sushi-lover.
CEI researcher Zach Zuckerman, along with 6
Island School students, are investigating how
marine debris - particularly plastic - is affecting
the marine food web of The Bahamas. Zuckerman
and his team have collected over 100 dolphinfish,
wahoo, and yellowfin tuna carcasses from anglers
at Cape Eleuthera Resort and Marina and Davis
Harbour Marina, both located near CEI’s campus
on South Eleuthera. The location at which each fish
is captured is recorded, and the stomachs removed
at CEI’s wetlab to be dissected in search of plastic
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Fig. 1: Wahoo (top) and dolphinfish (bottom) are highly
sought after sportfish, and are targeted for their fighting
ability and table quality meat. These species, together
with tunas and billfish, drive the economically valuable
Bahamian sportfish economy.
Fig. 2: A sugar bag originating from the Dominican
Republic. Within a few years this bag will break up into tiny
microplastics, easily available for accidental consumption
by marine fishes.
debris. To identify microplastics, the team runs the contents of each fish’s stomach through a
sieve, or a series of increasingly smaller screens, to separate prey and debris by size (Fig. 3).
Preliminary results indicate that 19% of wahoo, 23% of dolphinfish, and 20% of yellowfin tuna
captured in Eleuthera’s waters contain plastic in their stomachs. Some of this is easily identifiable
by eye such as pieces of plastic bag! Most of the debris, though, is less than 5mm in size and
identifiable only through the sieving process such as the 14 small pieces of clear plastic found in
a single yellowfin tuna (Fig. 4)!.
These preliminary results are quite startling; past gut content analysis of fish harvested near the
Pacific Garbage Patch suggests much lower occurrences of plastic ingestion by recreational
species, with only 2% of dolphinfish and no yellowfin tuna having been found with plastic in
their stomachs. These researchers, though, only searched the gut by eye and did not sieve the
stomach contents. Many anglers claim to have never seen plastic inside a fish, yet it would seem
that most have never looked quite close enough!
Please follow this research as we increase our sample size, add new recreational species to
the study, and quantify concentrations of free-floating plastic around Eleuthera by sampling the
Exuma Sound with a plastic trawl (blog coming soon). Contact [email protected]
with questions or to support our research efforts.
Fig. 3: Island School students remove the stomach from a
dolphinfish in preparation for a stomach dissection.
Fig. 4: This large hair bead and piece of trash bag were
discovered in a dolphinfish and wahoo (top), while these 14
small pieces of clear plastic film were discovered after sieving
the stomach contents of a single yellowfin tuna.
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Turtle Research Update
During the first week of May, Cape
Eleuthera Institute and the Sea Turtle
Research and Conservation Program were
honored to welcom Dr. Karen Bjorndal
and Dr. Alan Bolten to our facility. Dr.
Bjorndal and Dr. Bolten are co-directors
of the Archie Carr Center for Sea Turtle
Research at the University of Florida and
collaborators on the “Tracking Sea Turtles
in the Bahamas” Earthwatch program
conducted at CEI.
Dr. Bjorndal and Dr. Bolten came to CEI
to discuss the program as well as scout
out potential study sites for their newest
Research assistant of the Sea Turtle Research Program, Rachel Miller,
graduate student to investigate the effect
watching Dr. Alan Bolten take a biopsy from a green sea turtle caught in
of green sea turtles on the carbon cycle
Starved Creek, The Bahamas. (1)
of seagrass beds. They also accompanied the turtle team on a trip to Starved Creek. Here, Drs.
Bjorndal and Bolten taught the turtle team how to take skin biopsies from a sea turtle. These skin
biopsies will be used to conduct stable isotope analysis, an analysis that examines the diet of
the turtle, as well as genetic analysis. The genetic analysis will help give the team at CEI an idea
of which rookery (nesting area) the sea turtles came from as the green sea turtles feeding off the
shores of Eleuthera most likely traveled long distances from their hatching grounds.
On their final night at CEI, Dr. Bjorndal gave a presentation to the Island School students and
staff. Dr. Bjorndal was a doctoral student of Archie Carr, the grandfather of sea turtle research,
and her presentation gave background information on sea turtles in the Bahamas and provided
insight into the research she has conducted for the last 40+ years in The Bahamas. Dr. Bjorndal
initially monitored nutritional ecology of green sea turtles in the early 70’s but this has grown into
a long term monitoring program in Inagua, southern Bahamas. She and Dr. Bolten also monitor
abundance of sea turtles (green, loggerhead, and hawksbill) as well as growth rates of sea turtles
throughout various sites in the Bahamas.
The turtle team are grateful for the time they got to spend with these distinguished scientists and
look forward to their graduate student joining the team at CEI next year!
For more information on current turtle research at CEI, please contact Research Manager
Annabelle Brooks ([email protected])
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JOB OPPORTUNITIES
The Cape Eleuthera Institute has a number of work opportunities available that
we want our supporters to know about and spread the word. Please see below
for more information and feel free to send these postings along to any interested
parties. You can find the entire job listings and information on how to apply on the
provided links or on our website.
Cape Eleuthera Institute
Internships
Assistant Outdoor Educator
Research Assistant
Center for Sustainable Development
Sustainability Teacher
The Island School
Alumni Educator
Director of Communications
Environmental Art Teacher
Histories Teacher
Literature Teacher
Master Teacher
Summer Term Alumni Mentor
Deep Creek Middle School
Mathematics Teacher
STAY CONNECTED!
Don’t forget to follow the Cape Eleuthera Institute on social media! Like us on Facebook,
follow us on Instagram and Twitter (@CEIBahamas), and follow our blog for weekly research
updates (blog.ceibahamas.org).
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