The hard-knock life of a marine baby fish

By Cássia G. Goçalo

Most fish in the world’s oceans reproduce by releasing their reproductive cells (oocytes and sperm) into the marine environment, where the two meet and fertilization occurs. Fish like sardines, groupers, tuna and cobias use this strategy to spawn millions of eggs. About 24 hours after (more or less, depending on species) the end of embryonic development, baby fish are hatched, called larvae.

Eggs and larvae of fish

For a tiny larva to survive in the marine environment, a large amount of quality food is necessary (such as zooplankton, see "For plankton, size matters"). Babies need to be well fed to guarantee fitness and growth until they reach adulthood. In the ocean, there are many animals that feed on small organisms, and eggs and fish larvae have high nutritional value. Fish and other marine animals, such as jellyfish, consume millions of eggs and larvae each season, as just another step in the marine food chain.

Jellyfish Liriope tetraphylla capturing a cobia larva (Rachycentron canadum) 5 mm in size.

It was once believed this little fish lived floating in the seawater for days or even weeks until its eyes, mouth and fins were completely developed. In my doctoral project, I studied the behavior of these small larvae during the first days of life, and I observed that, in addition to floating, they have an amazing swimming ability. Larvae are able to achieve extremely high speeds while swimming to capture food, up to 40 times their body size per second. Note: the world’s fastest man swims only 1.5 times his body size per second!

In general, the swimming of marine organisms is related to feeding, breeding, and the escape from predators. To get food, fish larvae need to coordinate their bodies to move their fins, interpret prey movement, open their mouths, and then capture the prey. To get away from predators, they need to bend their bodies and change swimming direction to successfully escape. These behavioral patterns were recorded for grouper (Epinephelus marginatus) and cobia (Rachycentron canadum) larvae, in my studies. To perform this research we (Laboratory of Plankton Systems team and me, http://laps.io.usp.br/index.php/en/) set up an optical system with a similar configuration to a microscope but in a horizontal position, to study organisms 2-5 millimeters in size in a small aquarium. We filmed with a video camera that captures a high rate of frames per second (also known as "high speed camera"). See more at https://www.facebook.com/lapsiousp

Even with all this skill, survival rate of individuals is only 1% from egg to adulthood. This high mortality rate is due to predation and/or starvation. A small larva faces many challenges, but if successful, one day it will become a mature adult fish and produce a new generation of eggs and larvae, maintaining a natural balance between species and the marine ecosystem.

In the marine environment there are about 16,000 species of fish, many of which we know little about the larval behavior of. An example similar to the research done in my doctoral work is the study conducted on adult fish behavior through, which can be seen in documentaries presented by the National Geographic Channel (http://natgeotv.com/uk/hunters-of-the-deep/galleries/super-fast-fish ). The researchers offered different prey and filmed the swimming and feeding behavior of different species of marine fish. For the curious: access the page and watch the video "Blink of an Eye."

Questions and comments? Contact us or leave a response below!

See you on the next post!

References:

FUIMAN, L. A. Special considerations of fish eggs and larvae. In: Fuiman, L. A.; Werner, R. G. (eds). Fishery Science: The unique contributions of early life stages. Blackwell Science. p. 1- 32, 2002.

GOÇALO, C.G.; AQUINO, N. A. de; KERBER, C. E.; NAGATA, R. M.; LOPES, R. M. Swimming behavior of cobia larvae (Rachycentron canadum) facing prey and predator. 38th Annual Larval Fish Conference, Quebéc, Canadá. 2014

HOUDE, E. D. Emerging from Hjort’s shadow. J. Northwest Atl. Fish. Sci., v. 41, p. 53-70, 2008.

Labels: Cassia G. Goçalo, Marine Science, behavior, fish larvae

How to tell the age of a fish and other things

By Cláudia Namiki

Have you ever wondered how to tell the age of a fish? If it was born in an aquarium, it is easy to know, but what if it was caught in the wild? 

The teleost fishes have structures located in the inner ear called otoliths, which are used for balance and hearing. In Portugal, these structures are also known as "stones of judgment," which makes sense, since they are in the head of the fish! There are three pairs of otoliths and each has a different name: sagitta, lapillus and asteriscus. Otolith growth occurs through the alternating deposition of calcium carbonate and a protein that forms rings that can be observed in a cross section, much like those observed in the trunks of trees.

 

Otoliths of Myctophum affine larvae. Photo: Claudia Namiki.

In adult fish the otolith is big, thus it is necessary to cut, sand, and polish the otolith until the rings become visible. In larval fish the otoliths are small enough to see through and can simply be glued to a microscope slide. In the case of larval fish, the real work is to remove the otolith from from a fish between 2.0 mm and 2.0 cm length. If the larvae are so small, imagine the size of otoliths!! It is a difficult task that requires much patience. In Brazil we used to say that it requires the discipline and patience of a Japanese elder. I think I used the full 25% of my Japanese DNA while studying the larval growth of an abundant lanternfish species on the Brazilian coast (Myctophum affine). This species does not have a popular name in Brazil, because, although abundant and consumed by other fishes, it is not consumed by humans. In English they are called metallic lanternfish, but only fishermen or ichthyologists know of it.

The illustrious unknown Myctophum affine. Photo: Gabriel Monteiro. 

Look at the size of this fish larvae otolith! It is a great one! 

Photo: Campana, S.E.

http://www.marinebiodiversity.ca/otolith/english/

preparation.html

So what does this have to do with the topic? How do we know the age of a fish?

In most cases, the formation of the otolith rings is daily in the fish larvae and annual in the adult fishes. Thus, counting the number of rings present in a otolith, we can know the age of the fish in years or days, depending on its life stage. The most interesting thing is that we can relate the age to the length of the fish; with data from various fish, we can know how long it takes a species to reach a certain size. For example, the larvae of the metallic lanternfish can increase their size more than four times in less than a month! Now that is a fast growth rate! Larvae of other popular species such as sardines and mackerel also grow at a similar rate.

Knowing the growth rate of larval and juvenile fish is important because it helps us determine how long each species takes to become a reproductively active adult. This growth rate may be influenced by several factors with temperature as one of the most important. Higher temperatures speed up the fish metabolism, which helps the animal grow more quickly. This means that if we were a fish, we would grow faster in Brazil than in Russia! For example, lantern fish larvae can take between 27 days (tropical species) to 80 days (cold climate species) to become a juvenile.

When I first started to study otoliths, I was only interested in the age and growth rate of fish larvae. However, I discovered that these structures are even more fascinating than I first thought. Because they are quite resilient (in the case of adult fish), the otoliths can be found almost intact in the stomach content of other animals and at archaeological sites. Additionally, otolith shape is unique to each species, so it is possible to identify the species that has been consumed, or that inhabited certain place thousands of years ago. The otolith shape is so important that many works are devoted to describing them, and among them is one otolith identification guide recently published in the Brazilian Journal of Oceanography, by researchers of the Oceanographic Institute of São Paulo University (http://dx.doi.org/10.1590/S1679-875920140637062sp1) (which contains wonderful illustrations by our illustrator and oceanographer Silvia Gonsales).

Otoliths of Cangoá (Stellifer rastrifer) illustrated by Silvia Gonsales. http://dx.doi.org/10.1590/S1679-875920140637062sp1

Stellifer rastrifer otoliths. Photo: Cesar Santificetur. http://dx.doi.org/10.1590/S1679-875920140637062sp1

And the fish these are from, Stelllifer rastrifer. Photo: Carvalho Filho, A.

http://www.fishbase.org/photos/PicturesSummary.php?StartRow=2&ID=1196&what=species&TotRec=5

Moreover, the otoliths carry information from the environment where the fish lived (or should I say swam?). If we know which chemical elements are present in the otoliths, it is possible to know where the fish was throughout its life.
So, while otolith may be just a simple guidance instrument for the fish, for us it gives us access to a  world of information about the life history of these important organisms.


To find out more you may visit:

http://www.usp.br/cossbrasil/doc_labic.php

Campana, S.E. 2011. Otolith Microstructure Preparation. Available at: http://www.marinebiodiversity.ca/otolith/english/preparation.html

Campana, S. E. & Jones, C. M. 1992. Analysis of otolith microstructure data. In Otolith Microstructure Examination and Analysis (Stevenson, D. K. & Campana, S. E., eds), pp. 73–100. Canadian Special Publication of Fisheries and Aquatic Sciences 117.

Conley, W. J. & Gartner, J. V. 2009. Growth among larvae of lanternfishes (Teleostei: Myctophidae) from the Eastern Gulf of Mexico. Bulletin of Marine Science 84, 123–135.

Katsuragawa, M. & Ekau, W. 2003. Distribution, growth and mortality of young rough scad, Trachurus lathami, in the south-eastern Brazilian Bight. Journal of Applied Ichthyology, 19, 21–28.

Namiki, C.; Katsuragawa, M.; Zani-Teixeira, M. L. 2015. Growth and mortality of larval Myctophum affine (Myctophidae, Teleostei). Journal of Fish Biology, 86, 1335-1347. doi:10.1111/jfb.12643, Available at: wileyonlinelibrary.com

Rossi-Wongtschowski, C.L.D.B., Siliprandi, C.C., Brenha, M.R.,Gonsales, S.A., Santificetur, C., Vaz-dos-Santos, A.M. 2014.Atlas of marine bony fish otoliths (sagittae) of Southeastern- Southern Brazil Part I: Gadiformes Macrouridae, Moridae, Bregmacerotidae, Phycidae And Merlucciidae); Part II: Perciformes (Carangidae, Sciaenidae, Scombridae And Serranidae). Brazilian Journal of Oceanography, 62(special issue):1-103. Available at:
http://dx.doi.org/10.1590/S1679-875920140637062sp1

Zavalla-Camin, L. A., Grassi, R. T. B., Von Seckendorff, R.W. & Tiago, G. G.1991. Ocorrência de recursos epipelágicos na posição 22°11’S - 039°55’W, Brasil. Boletim do Instituto de Pesca 18, 13–21.

The ship’s balance...

By Izadora Mattielo

Have you ever asked how ships are balanced at sea? Or how it can carry people and merchandise without tipping over? It is easy to imagine that there is an ideal maximum weight, designed and calculated by engineers, that the ship can support without sinking. OK. But how does how can this keep its balance when it is empty?

Credit: http://ultradownloads.com.br/papel-de-parede/Navio-Tombado/

The answer is easy: it needs to add weight when it is empty and then release the weight while loading it with people or merchandise.

In the beginning, there were several attempts with stones and pieces of wood, but due to the effort required to add and remove these materials, a better thought was to use the seawater! Pumps could be used to pull in and throw out the water when ship was docked. This method is the method we still use today; ships have a ballast tank, which can hold ballast water that is pumped in and released.

Credit: The environmental risk of ballast water – ONG Água de lastro Brasil. (http://stateofthecoast.noaa.gov/invasives/ballastwater_large.jpg)

That is where my story begins!

Imagine an empty ship going from China to Brazil, where it will be loaded with merchandise. As already explained, the ship would have to pump water from the Chinese coast to keep balance while traveling.

The water pumped in however, is not pure and has a lot of organisms that who are trapped inside the ballast tank. You might be asking: isn’t there a mesh filter that can be used to avoid trapping these organisms? Yes, but it’s not efficient, especially for microorganisms.

A second problem is, according to International Maritime Organization (IMO), ships are to exchange water in the open sea, because there are different physical and biological conditions in port that the organisms from the open ocean cannot survive. However, this does not happen. Aside from many ships not changing water at sea, there are several organisms that can resist both the travel and different environmental conditions.

When arriving at the destination port, these non-native organisms are discharged along with the ballast water, causing serious problems for the local fauna and flora, as well as public health. Can you imagine the environmental impact?

Because of this, there are many countries that belong to IMO doing research to solve this problem. One of these solutions is the treatment of the ballast water inside of the tank. There are many treatment proposals: mechanic, physical, and chemical. These are currently either in testing, generate waste, or are not completely efficient.

I did work with phytoplankton, marine microalgae explained here. These microscopic organisms can be resistant to many treatments, and some species are toxic to animals. In fact, red tide is caused by a microalgae group.

My challenge was then, to find ways to eradicate these microscopic algae from the ship ballast water. I tested three treatments: exposure to UV, ozone, and Peraclean, a chemical with characteristics similar to hydrogen peroxide. As I developed this project, I knew that these treatments were of huge importance and needed further studies done.

The most interesting stage of this project was the partnership with the company Brasil Ozonio (a company that works with the University of São Paulo). Don’t be afraid to make university-industry partnerships; much of our knowledge doesn’t go forward because the researchers don’t want to expose their work and ideas. This partnership was essential to my work.

Credit: Izadora Mattiello.

After conducting a series of experiments, my best result was with the ozone! I was able to eradicate even the most resistant microalgae (the dinoflagellates), which no other treatment had managed to kill. In addition to being effective, this treatment doesn’t generate waste into the treated water, so it may be safely discharged overboard.

In future posts, I will discuss my results in more detail, but if you want to know a little more about it, follow the links about my dissertation:

http://www.teses.usp.br/teses/disponiveis/21/21134/tde-02022015-135423/pt-br.php

http://www.usp.br/aun/exibir.php?id=6118&edicao=1076

See you!

For plankton, size matters

By Catarina R. Marcolin

Today, I want to discuss a subject that has fascinated me since I started my PhD. We are often asked “What is you PhD about?” and the general reaction of grad students is simply to avoid the subject or to just reproduce the title (some long and complicated name that nearly nobody, let alone ourselves sometimes, is able to understand). Or we simply say that it is too hard to explain with simple words. Notice how this sounds like we think too much of ourselves: we are very smart and outsiders will never be able to understand what took us so long to embrace.

Well, that is exactly the kind of attitude that the grad student should avoid. This blog is designed to be a place where academia may connect with society. I had a beloved professor that used to say that every grad student should be able to explain his/her project to his/her grandmother, and only once we accomplish that, would we finally be confortable with the theory behind our research. So, I’ll try to do exactly that, a little late I confess since I have already finished my PhD. I’ll explain in a simple – but not simplistic – way the work I developed during my PhD.

I am interested in plankton, more specifically, the zooplankton! No, I’m not referring to SpongeBob’s villain, but they are nonetheless, interesting creatures worth knowing a bit more about. Zooplankton are tiny aquatic critters, usually invisible to the naked eye. They are traditionally described as organisms that travel with the currents because they don’t have enough “strength” to swim against it, due to their small size. But that does not mean they are lazy guys. On the contrary, many of them are able to vertically migrate large distances through the water column, sometimes hundreds of meters, on a daily basis.

Watch video in: http://laps.io.usp.br/index.php/en/projects/81-english/laps/projects/97-samba

Example of food chain.
Source: http://lifeadrift.info/

Zooplankton are very important in marine food webs, and they are also fundamental to other important processes in the oceans (we can discuss that in another post). These organisms feed on phytoplankton (the photosynthetic plankton that are to the oceans, what the trees are to the Amazon Forest) and are eaten by fish, which are ultimately eaten by larger fish, marine mammals including whales, and even us humans. So you can imagine that if there are few plankton in the area, there will also be less fish and other organisms in higher trophic levels. This includes a limited supply of fish for us, which means less sushi, and I love Japanese food!

If zooplankton are so important in mediating the transfer of biomass and energy from primary producers (phytoplankton) to higher trophic levels (fish, birds, whales, man) then we must understand these feeding relationships very deeply, don’t you agree? Well, one of the golden rules in the ocean is that organisms always (or almost always) feed on organisms that are smaller than themselves. That is why size matters when zooplankton choose the dinner menu. Many researchers have studied the flow of biomass and energy through the trophic levels. For example, it has been calculated how much of a “dinner” is actually absorbed by a zooplankton and how much is left to the fish, birds and whales that feed on the same guy. This information can potentially explain a lot of things about the oceans.

But how? Well, if you measure the size of organisms, calculate their weights, and plot this information in a graph, such as the one in this page, you will notice that there is always more biomass accumulated in the small organisms than in the bigger ones. By accumulated biomass I mean the biomass of all organisms in that particular size range. What does that mean? It means that to satisfy the hunger of one big guy, it is necessary to have a whole bunch of small guys. You must remember there is energy loss in every “meal” because total nutrition is never absorbed with everything that we, or any other organisms, eat.

Based on these facts, the biomass size spectra theory was developed. This theory relates the shape of the biomass distribution through size classes (and also the mathematical indices associated with it) with properties of the ecosystems. Personally, I think it is absolutely amazing how a simple mathematical index can be used to determine the energy transfer efficiency in an ecosystem, taking into account productivity, predator-prey interactions, and the number of trophic links in the oceans.

My PhD was based on this theory with a scary name (spectra tends to conjure images of ghosts, no?), but the theory is not as complex as it seems. To get my data, I collected zooplankton samples with a simple net (as seen in the photo) aboard several cruises. When back in the lab, all I had to do was to scan my samples with a waterproof scanner (the ZooScan), and very useful software automatically classified, counted, and measured the size of each organism. I also learned how to program in R and Matlab to analyze the enormous amount of data for me, because life is short and I have other hobbies in addition to science to dedicate myself to, such as this blog!

The results I found for the coast of Ubatuba, Sao Paulo and Abrolhos Bank revealed that the mathematical indices associated with the biomass size spectra theory can be used to detect differences in the zooplankton community caused by seasons and local features (water column stratification, depth, proximity of the coast). That means these indices are useful for monitoring oceanic ecosystems because they are easily calculated – granted you have technology to help – and there is no need to identify species, which is usually a time-consuming task when we are talking about plankton.

If you are interested in the subject, my PhD dissertation is available at this link:

http://www.teses.usp.br/teses/disponiveis/21/21134/tde-12052014-173357/pt-br.php.

Three minutes, one slide, and lots of fish eggs

By Jana M. del Favero

Would you be able to explain your research to an audience of academics from all different disciplines, in just 3 minutes, with only one slide? That is the premise of a competition called the Three Minute Thesis (3MT). 3MT was created at the University of Queensland, Australia in 2008, and it has been performed at the University of Massachusetts Dartmouth, USA since 2011. (Details about the competition can be found here: http://www.threeminutethesis.org).

While thinking about the goals of this blog, I decided to participate in the competition this year, as it does exactly what we try to do here: talk about science to a diverse audience while keeping it interesting and educational. I signed up thinking only about the training; I would have to prepare and memorize my text and then deliver the presentation (in English!). Of course, I also had the ultimate goal of winning (who turns down a chance to earn $1,000?).

Unfortunately, I did not get rich on April 29th, 2015, but as expected, it was great practice and lots of fun. It was interesting to watch presentations about the research from various fields: engineering, arts, administration, etc. There were nervous people and people who seemed to have come straight from a theater stage. You can watch some videos of previous years by visiting the following website: http://www.umassd.edu/graduate/spotlights/three-minutethesiscompetition/.

You can read the transcript of my talk and learn more about my research below:

Many people do not know, but fisheries management is not just based on adult population data. It is also important to study early life stages for better stock management. For example, as fish eggs are usually spawned in the water column, knowing when and where they are helps to define spawning sites and periods.

But, before doing any kind of fish studies, it is necessary to know who they are. Fish egg identification is time consuming and difficult. After sampling on board, you need to sort all of the fish eggs from the plankton sample, using a microscope. Sorting the eggs from the family I am studying is easy because their eggs have an ellipsoid shape.

The problem is reaching the species identification. As each group presents different size and shape, the identification has previously been done by manually measuring each egg and then counting.

Figure 1. The single slide presented during the competition. The eggs illustrations are from Nakatani (1982).

In my doctoral thesis, I want to verify long-term fluctuations in the abundance and distribution of eggs from a fish named Argentine anchovy on the Brazilian coast. This small fish is one of the most common fisheries resources in Argentina and Uruguay. At the Brazilian coast they haven’t been commercially fished yet, but some studies have suggested that Argentine anchovy can be sustainably fished in Brazilian waters.

Coming back to my thesis, when I mentioned that I am studying long-term fluctuations, I didn’t mention that by long-term I meant 40 years of data, totaling almost 2000 samples. That is a huge amount of samples and it would take my whole PhD period just to identify all the eggs. The solution was to create a faster and more accurate methodology, so I did it.

I used a digital camera attached to a microscope to image the eggs, and using the photos, I got the measurements. After that, I created a model that automatically gave me the counts of eggs within each species. This new model has over 90% accuracy and can be used by any researcher to optimize their time and effort.

In the end, besides taking four years to identify the eggs for my thesis, I identified more than 100,000 anchovy eggs in just one year, allowing enough time to continue my research project.  

If you are interested in this methodology, the paper is already in publication, and it can be accessed in the following link or requested by email.

http://onlinelibrary.wiley.com/doi/10.1111/jfb.12594/abstract

See you soon.

Devastatingly beautiful: the growing problem of Lionfish invasion

By Corey Eddy and Jana M. del Favero

Two lionfish have been sighted in Brazil, both in the southeastern area of Arraial do Cabo (Rio de Janeiro). The first one was in 2014 and another more recently in March 2015. But with only two individuals spotted, why should we care?

The lionfish!

Brazilian experts are still debating how these lionfish ended up in the Brazilian waters and if there may be more individuals in deeper waters, not observable by divers (details at: http://ciencia.estadao.com.br/blogs/herton-escobar/mais-um-peixe-leao-e-encontrado-na-costa-brasileira/).

While there is no consensus, I asked a colleague, Corey Eddy, to write about the invasive population of lionfish in Bermuda; I wanted to know what is being done there and what measures could be adopted in Brazil. Below it is the text he wrote:

Since the discovery of lionfish in Florida in 1985, their population expanded rapidly to stretch from Venezuela to Rhode Island (US). It was thought their range of invasion could eventually stretch as far south as Uruguay. As lionfish are recognized and avoided by prey in their native territory, they have evolved into opportunistic predators with broad diets. However, due to prey naivety in their invasive range, lionfish are able to consume large quantities of invertebrates, juvenile fish, and small-bodied adult fish, many of which play important ecological or economic roles. Consequently, research shows that lionfish can reduce juvenile reef fish populations by nearly 80% in as little as five weeks. Bolstered by the lack of any natural predator, lionfish populations in the Atlantic have reached densities far greater than in their native range, with the potential to affect community structure, biodiversity, and the health of coral reef ecosystems. Fortunately, they are delicious and it only takes one minute to remove their dangerous spines, making them perfectly safe to handle. If we can create a fishery for them, we can save the ocean. We have to eat them to beat them.

Representation of the worldwide lionfish distribution. Diagram by Naira Silva

Source: Lionfish illustration (http://www.supercoloring.com/pt/desenhos-para-colorir/peixes).

My doctoral work is part of a larger project, funded through the UK’s Department of Environment, Food and Rural Affairs, that is investigating the biological and ecological characteristics of the lionfish population around Bermuda and the potential impact lionfish may have upon the structure and function of Bermuda’s coral reef ecosystem. For my first chapter, I will be using the data we collect on lionfish abundance and distribution to estimate the population size. Our team is assessing lionfish abundance via underwater visual surveys at 15 sites in each of five depth zones across the Bermuda platform (10, 20, 30, 45, and 60m) using SCUBA or appropriate technical diving equipment (i.e. trimix diving with multiple tanks). Using a roving search protocol that encompasses cryptic habitats, divers record all lionfish seen and attempt to capture each individual using a pole-spear. Following capture, all lionfish are measured, weighed, dissected, and processed for further analyses. Belt-transect surveys of reef fish, focusing upon small and cryptic species, are conducted concurrently to determine the abundance and distribution of potential prey. A number of these sites are being resurveyed after one year to assess re-colonization rates. This data will also facilitate the development of a distribution map that aids removal activities targeting lionfish at key locations and times that account for seasonal population fluctuations and movement patterns.

Photo by Jorge Sanchez

My next two chapters will document the life history characteristics of this species to estimate population growth as it pertains to their potential ecological impact. In chapter two, I will examine the demographics of the lionfish population as well as growth rates and longevity of lionfish in Bermuda. This work utilizes standard otolith (“fish ear bone”) aging techniques applied to specimens captured during our underwater surveys and opportunistically from other divers, commercial fishermen, and permitted lionfish hunters. Following this, my third chapter will examine the reproductive condition and quantify the fecundity of lionfish. Gonads will be weighed, sectioned, and analyzed by traditional histological methods to determine overall fecundity, reproductive seasonality, and the developmental stage of fish, thus providing an estimate of the reproductive potential driving the overall population growth.

In my final chapter, we are investigating the feeding ecology of lionfish to explore the impact they may have on the native fish and invertebrate communities, as well as the entire local ecosystem, and to identify factors driving the population’s distribution. This research involves conventional stomach content analysis (SCA) complemented with more advanced stable isotope analysis (SIA) that reveals details not detectable through traditional methods. Because the stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N) in the tissues of predators are directly related to the ratios found in their prey, the change in these ratios relative to a standard, δ13C and δ15N, are used to indicate the primary carbon sources for a consumer and an estimate of trophic position, respectively. To further indicate the potential impact of lionfish on Bermuda’s reef ecosystem, we will also perform this analysis on prey species (i.e. those identified by the SCA) and others we know are competing with lionfish for these same resources. By plotting δ13C and δ15N of lionfish and these various species, we can see the extent to which lionfish are utilizing resources needed by native species.

When completed, this project will estimate the extent to which invasive lionfish could impact Bermuda’s coral reef ecosystem and help mitigate that impact by providing data on lionfish abundance and distribution to assist the Bermuda Lionfish Task Force and the Department of Environmental Protection (http://www.lionfish.bm) in developing a comprehensive plan that facilitates large-scale, long-term removal of this species from local waters. Controlling and reducing the continued growth of the lionfish population is a crucial part of any effort to minimize negative impacts on native fish species and coral reef ecosystems, and avoid secondary impacts on fisheries and tourism.

In addition to my doctoral research, I am heavily involved in public education and one of the projects I work on may be very useful to implement in Brazil. As a volunteer for the Ocean Support Foundation (http://www.oceansupport.org), I run the Bermuda Lionfish Culling Program on behalf of the Department of Environmental Protection. This program allows any Bermudian resident, over 16 years of age, to receive the proper training and a special permit to hunt lionfish. This is different from a traditional spearfishing license because permitted lionfish hunters are allowed to hunt lionfish while using SCUBA, within one mile of shore, and on shipwrecks and other protected sites, situations normally forbidden by Bermuda law. To date, we have certified over 500 hunters, all of whom are a major help in removing lionfish and keeping Bermuda’s reefs clean and healthy. As Brazil has only recently been invaded, these early days are the perfect opportunity to mobilize SCUBA and free divers, fishermen, and environmentalists to get into the water and start hunting. Every lionfish that is removed greatly helps to preserve and protect Brazil’s marine environment, especially at this early point, when there may be very few lionfish around.  

Corey Eddy biography:

Photo by Groundswell Bermuda.

Corey Eddy is a PhD candidate at the University of Massachusetts Dartmouth. He received his bachelor’s degree from the University of Rhode Island, whose study abroad program first brought him to Bermuda for a semester at the Bermuda Institute of Ocean Sciences. He is also a Fellow through the National Science Foundation’s Graduate Research Program and a member of the Bermuda Lionfish Task Force. As a volunteer for the Ocean Support Foundation, he developed and currently manages the Bermuda Lionfish Culling Program on behalf of the Department of Environmental Protection. His research interests focus on studying the life history characteristics, habitat use, and feeding ecology of ecologically important predators.
Contact: corey.eddy@umassd.edu