While it has nothing to do with my research, trawling is one of the most fun things I get to do, so I jump at every opportunity that I can to make a trip (as I have blogged about a few times before). Recently, we took some summer camp kids from Southampton Bath and Tennis Club out on the boat to do some fun trawling. This group of kids was one of the most enthusiastic group I have been on a boat with. They were all excited to get out on the water, and didn’t hesitate to dig into the tray full of algae and seagrass to pick out all the little critters.
Kiddies digging into the catch
The catches didn’t yield too much out of the ordinary – flounder, crabs, tomcod, sticklebacks, pipefish, shrimp, the usual things we typically get. But we did get a lot of them. We seemingly were constantly pulling baby winter flounder out of the catch tray (I want to guess they were all young of the year, but there was a range of sizes, so it could be a couple of year classes). There were a lot of blue crabs which we removed before the kids could dig in. And there was so many pipefish, including many pregnant males (yes, male pipefish carry the young, and apparently, will abort eggs from “unattractive” partners).
baby flounder and another fish
Kiddies around the holding tank
We even caught a few tropical fish. This time of year we typically catch tropical fish which come up in the Gulf Stream and get transported into Long Island south shore waters in meandering eddies. We typicallys start to see butterfly fish, some gray snappers, occasionally small groupers, cowfish, burrfish, and file fish.
Filefish
But the real star of the show this week was the seahorse. Seahorses are native to NY waters, as the lined or northern seahorse, Hippocampus erectus, is found from Nova Scotia to Argentina. It uses a variety of structured habitats, however, on Long Island, they typically utilize eelgrass as their habitat. They use their tails to hold onto shoots of grass and sit still to wait to suck up little unsuspecting critters like small amphipods and shrimp to eat. Like their cousins the pipefish, male seahorses also carry the eggs. Lined seahorses are listed as “vulnerable” by the World Conservation Union’s red list of endangered species. They used to be common in Long Island waters, but loss of their primary habitat, eelgrass, has caused populations to be reduced. Hopefully, with the help of the seagrass group from Cornell and their work with seahorses, these magnificent sea creatures can return to having large, healthy populations around NY.
So my labmate emailed this new Science Friday video to me this morning. Long story short, when we go to the pet store I tell him to make sure he sees the fish eat before he buys it, and when the guy in this video said the same thing, Brad emailed it to me since I would appreciate it. The video focuses on an aquarist to the stars of sorts, Justin Muir of City Aquarium. As it turns out, the wholesaler, Merit Imports, in this video is where I used to go to purchase fish for the pet store I used to work at, oh about a decade ago (well, probably more than a decade now!). So I was particularly excited when I heard the name of the distributor and recognized the faces – the same guys who were running it back when I was going there. As it turns out, they used to work at a pet store for my boss, so we learned from the same “teacher” at the Rainbow Aquarium. The shop has since closed, due to issues in this poor economy and such, and even though I have moved on from that phase in my life (when I worked there I had 14 fish tanks at home), I still carry what I learned there with me Anyway, cool video.
Well I finally picked up a copy of the this month’s National Geographic with the artificial reef article in it. And by picked up I mean borrowed from a waiting room, but I have to go back on Thursday and will return it then, so I am no thief. Anyway, I briefly blogged about this article already when I was depressed about winter weather and longing to be someplace else, preferably warm, and diving. That’s because I love diving. And sometimes, there’s nothing better than diving on wrecks. Sometimes. Don’t get me wrong, there is plenty of cool things to see on naturally occurring bottom. But artificial reefs created by wrecks are definitely very cool (so is this video).
Image from Pangea-yep.com
But actually reading the article, in print, and seeing the pictures, made me want to blog about it all over again. This time, though, I will concentrate a little more on artificial reefs themselves. Artificial reefs are quite simply structures artificially sunk by man to create a hard bottom in an otherwise sandy and structure-less habitat. The idea is to mimic some of the functions of naturally occurring reefs – namely, by providing a hard, 3-dimensional structure that sits in the water column. These reefs are intended to attract and enhance many marine species, in particular, finfish. In fact, fisherman have been sinking things for decades (probably even centuries) to attract fish, so this is not a particularly novel idea. However, the number and magnitude of artificial reefs has certainly expanded greatly in recent years (Edit – as Dr Alan Dove pointed out in the comments below, there have been numerous “natural” or unintentional wrecks sunk over the years. So the rate of sinking artificial reefs might not have increased, but I imagine the rate of intentionally sunk reefs has). Typically, “Artificial reefs” just consisted of junk. Now, many have expanded to be large decommissioned ships, subway cars, and oil rigs (and other cool things). And even more recently, companies are creating artificial reefs from concrete, such as Reef Balls, which I think are pretty cool (and, if you are lucky, when you die, you can be commemorated for eternity as an artificial reef ball! Sign me up!).
It might not happen over night, but eventually these sunken structures become teeming with life. Swirling currents around these structures can kick up and contain plankton, which attracts small planktivorous fish. These little guys, in turn, attract larger piscivorous fish. In addition to seeking food, many fish arrive simply to seek shelter in the many nooks and crannies that artificial reefs provide. But its not just fish. The artificial structures also become colonized by invertebrates and macroalgae, creating a crusty layer of living organisms growing as a living shell of sorts on the submerged structure. This living structure offers more nooks and crannies for smaller creatures, and provides food for numerous species that inhabit the reef. It essentially becomes just like a natural, living reef, with the only difference being that the underlying structure is man-made. Typically, when we think of artificial reefs, we think of tropical locations. However, they are also used in many temperate coastal waters to enhance fisheries, including Maryland, South Carolina and New Jersey. Here, they create ecosystem structure typically only present on the few limestone rocky outcroppings that stick out of the sand bottoms.
Despite providing food and shelter to numerous species, there are certainly detractors, and artificial reefs aren’t without certain cons. One major concern is that some things are just tossed in the ocean as junk, but that companies/organizations/municipalities/entities use the “artificial reef” moniker as an excuse to dump crap. Its cheaper to just toss things into the water than dispose on land, and so sometimes, things are called reefs just as an excuse. That is bad. Additionally, many things that are sunk have toxic substances on them, which can actually do more harm to the environment, leaking contaminants for the life of the reef. It is for these reasons that there are now strict, stringent regulations for sinking artificial reefs.
But one of the biggest complaints against artificial reefs is the very reason they are created in the first place – they concentrate fish. The complaint is that these concentrations make fish easier targets for fishermen, and can be potentially harmful to specific species. According to the NatGeo article, some biologists believe that this artificial enhancement of certain fishes, can be extremely detrimental to stocks. One such fish that is likely being negatively impacted by artificial reef structures is the red snapper, which concentrate around the structures and become easy targets for fishermen. In other words, these artificial reefs might make fishing as easy as shooting fish in a barrel. Obviously, acting as fish attractants with easy access can be harmful to fish populations, and some might argue that recreational fishermen are quite capable of decimating fish stocks, even in the absence of commercial fishing pressure
Clearly there are pros and cons of artificial reefs. However, it is my opinion that the pros outweigh the cons. And an easy way to eliminate the major negative impact of artificial reefs – the potential to overfish exploited stocks due to large congregations of target species around these structures – is to incorporate reefs into marine reserves and no-take zones. Yes, this might defeat the purpose of the reefs, and many will argue against this. I am not suggesting all artificial reefs become no take zones, but by leaving some as no take refuges, the reefs could serve there original purposes. While there is some debate as to the usefulness of marine reserves on highly mobile species, it stands to reason that artificial reefs create habitat where there is otherwise none, and enhances the local ecology of the area of the reef, enhancing species abundance and diversity. Plus, they are just awesome to dive on.
Lionfish from my Fiji dive trip. It was upside down under a coral ledge
So wow. I’m not saying it has anything to do with me, but I made a post about lionfish a few months back, and had a very special guest blog by colleague Amber Stubler about her experience capturing lionfish with a spear gun and eating them. A commenter was concerned about that post, indicating that some research is showing that lionfish may contain ciguatera poisoning, so I had already decided to do a new post about that. But then, in the last 2 days, lionfish are making the news – first in Florida, then in the US Virgin Islands.
In Florida, dive master Randy Jordan of Emerald Dive Charters is the self-proclaimed “lion-tamer.” He has caught 331 lionfish to date, including his most recent haul, a 16 inch (!) 2 and a half pound fish. According to Fishbase, thats about as big as they get. According to the article, Jordan is scheduled to give a lecture on the subject on February 26th at the Loxahatchee River District meeting to talk about his special device to catch these invaders.
Then just yesterday, an article about the invasion problem in the USVI, where the lionfish now number in the thousands. The governing agencies there are planning meetings with divers, fishermen and businessmen to discuss the problem and how to combat it, and, in particular, to get divers and fishermen to report their kills. The worry is that these invasive voracious predators will wreak havoc on the local reefs and hit the major tourism industry.
Lionfish are getting a lot of attention currently. And I have advocated the consumption as an eradication plan. But as I mentioned, commenter John Rubattino from the USVI had commented his concerns about ciguatera poisoning being prevalent in fish caught there. This would create a major problem, as ciguatera is a food poison, and when humans consume fish that contain the toxin, they often experience nausea, vomiting, diarrhea, pain, dizziness, vertigo, chills, rashes, and other symptoms.
So how does one get ciguatera poisoning? Again, its a food poisoning which results from eating large predatory tropical fish which contain the poison. According to the CDC, these fish include barracuda, certain snappers and groupers, jacks, king mackerel and hogfish. But where does the toxin come from, since these fish don’t produce it themselves? Tiny microalgae. In particular, this toxin is produced by a harmful dinoflagellate known as Gambierdiscus toxicus. When it grows, it often settles on reef structure and macroalgae where it is consumed by herbivores and small predators. Then these fish are consumed, and so on and so forth up the food chain. But the toxin is not harmful to the fish. So the large predators listed above contuinue to accumulate (a process known as bioaccumulation, also here, one of the reasons why you shouldn’t eat too much tuna or many other fish due to mercury) the toxin. Then, when humans eat those fish, they get extremely ill.
So I did some research on the itnerwebs about lionfish and ciguatera. Lionfish already produce their own toxin, present in their spines, but the thought was as long as they were processed carefully, that would not be harmful to humans. Surprisingly, there is little information about lionfish and ciguatera. There are a few posts from the Caribbean Oceanic Restoration and Education (CORE) Foundation in the USVI about lionfish with ciguatera, and how to proceed. Attached 5. Ciguatera is a .pdf from the Caribbean Epidemiology Centre about ciguatera cases in the Caribbean.
So its now out there and at least something to think about. There haven’t been many reported cases, but it might be worthy of investigation in the future. Obviously, lionfish present a considerable risk to the coral ecosystems they are invading, and so eradication must be considered. A simple way is to encourage locals to fish and eat them, and hopefully fish them out. However, if they might present a risk to human consumption, this idea needs to change. Research is warranted to resolve these issues.
A few months ago I made a post about lionfish being fished an eaten as a way to eradicate these invasives from the Caribbean. One of the places where this was being done is Jamaica, and if you remember correctly, last week I posted about a tropical course that undergrads from Stony Brook get to take in the laid back paradise. My labmate, Amber Stubler, is there as well, working on her dissertation research, but also hunting and eating lionfish. So I thought she should tell us about it (also, all the pictures are Amber’s):
After much groveling, John finally convinced me to write a “celebrity” blog about my trip to Jamaica. Rather than bore you all with the details of my sponge research (which you can read about here, here and here), I decided to write about another issue going on throughout the Caribbean- the invasion of lionfish, and what the Jamaicans are doing about it. For those who did not know- Lionfish (Pterois volitans) are native to the Pacific and likely arrived in the Caribbean via the aquarium trade (however ballast water transmission cannot be ruled out). The earliest sightings of lionfish in the wild (confirmed by USGS) were in southern Florida in 1992, and since then lionfish have been reported from Long Island to Venezuela. The USGS website has a really awesome animated map of the invasion here, which goes from 1992-2010.
I have been coming to Jamaica on a regular basis since 2007, and saw my first lionfish in 2009. I specifically remember taking about a thousand pictures of it, because even the marine scientist in me cannot resist a pretty fish picture. Since then, their populations have exploded, and when I say exploded, I mean I saw one in 2009, and on this trip I could easily count between 15-35 fish in an area the size of a football field underwater. So at this point you should be saying, “Amber, what’s the big deal with these lionfish, after all they are pretty and quite frankly the Caribbean could use a few more fish.” The problem is that they are voracious predators who will eat small invertebrates, juvenile fish, and anything else that will fit in their greedy mouths. This poses a threat to all the indigenous reef species as the lionfish eat all of the native species’ food, or just plain eat all of the native species. Also these guys pack powerful venom in the spines on their fins, which will ruin anyone’s dive/snorkel adventure. And since these guys are invasive, they have few natural predators which means they are free to roam about the Caribbean.
This, my friends, is where we come in.
We’ve all learned a valuable lesson that the best way to get rid of a fish species is to eat them (examples: cod, Atlantic salmon, etc). So what’s a country like Jamaica to do? Eat ‘em to beat ‘em (which by the way is the Bahamas official lionfish slogan). The Jamaican Ministry of Agriculture and Fisheries has begun an annual lionfish derby where prizes are awarded for the most lionfish caught over a 3-day period. They also hold seminars on how to safely catch, clean, and cook lionfish. Here at the Discovery Bay Marine Lab, staff members regularly go on lionfish hunts, bringing back dinner for their families and samples for Dr. Dayne Buddo, who studies invasive species at the Centre for Marine Sciences, University of West Indies. Dr. Buddo has spearheaded (no pun intended) many public outreach events teaching locals about the biology of the lionfish, the impacts on the ecosystem, and how to treat a lionfish sting. He also shares some of his favorite recipes, and cooks the fish up for skeptical Jamaicans.
After seeing Dayne spear several lionfish during one of our “fun” dives (ie not for research purposes), I decided it was time to take part in the action. So I broke out my shiny new speargun (specifically bought for this trip), and started wreaking havoc on the lionfish at my study sites. Over a course of our 2-week trip we managed to kill about 36 lionfish, and although that doesn’t really sound like a lot, we actually only brought the speargun out about 6 times, which means that our average was about 6 fish per dive. The largest we caught was 13 inches, and roughly 1 lb, certainly not a record, but a lionfish of that size can produce 30,000 eggs at a time, so I like to think that our killing spree helped save the reef from a few future lionfish. The great part about this whole kill-every-lionfish-you-can ideal is that it is uniting the fishermen against one species and will hopefully help eliminate/decrease the lionfish population here in Jamaica. Jamaica is already one of the most overfished reefs that I have ever seen, so having the fishermen focus on an invasive species gives the native fish a break from fishing pressure and keeps food in people’s mouths.
You can do your part too! Check out this awesome cookbook to become a full-fledged invasivore, and donate to a great non-profit organization dedicated to marine conservation.
Each year my adviser Bradley Peterson and fellow professor Joe Warren take a group of undergraduate students to Jamaica to participate in a course called Tropical Marine Ecology. This year is no different, although they ended up there a day late due to the most recent snow storm. That said, they all got there safe and appear to be settled in nicely. The idea behind the course is to get the students to learn about tropical marine environments by actually seeing them first hand – many of the upper level marine classes at Stony Brook are experiential in that students get hands on experiences in the field. Tropical is no different. The first few days will consist of lectures and snorkeling around to learn about the species in Discovery Bay, where the group stays. Once they take their practical, the students need to conduct a research project which they then write up for their grade in the course.
It is a short course (only ~2.5 weeks), so it is hard to accomplish very rigorous scientific experiments (also, any equipment they use needs to be brought with them, which also makes things difficult), however, the students undertake a variety of projects, investigating mangroves and seagrasses, coral cover, sponge communities, fish territories, etc. Some of the research under taken is of high quality and warrants publication. One such publication came from a group of students when the trip still went to the South Pacific where they investigated how Stegastes damselfish controlled algal assemblages, and the interplay between herbivory and nutrient addition. (Gobler, C. J., Thibault, D.B., Davis, T.W., Curran, P.B., Peterson, B.J., Liddle, L.B. 2006. Algal assemblages associated with Stegastes sp. territories on Indo-Pacific coral reefs: Characterization of diversity and controls on growth. Journal of Experimental Marine Biology and Ecology 336: 135–145).
More recently, a colleague of mine investigated the difference in growth rate and grazing of Thalassia between groundwater influenced and non-groundwater sites in Discovery Bay, Jamaica, with some interesting and unexpected results. That manuscript is currently submitted. In addition, thanks to her undergraduate visit to Jamaica, Amber developed her dissertation project investigating sponge community dynamics and recruitment on reefs impacted by sedimentation due to the creation of mega-resorts and those with no impact. She visits Jamaica frequently to collect data (I have tried to get her to blog about this stuff, maybe one day she will).
Anyway, back to the course. For many students, it is their first time in a tropical environment, their first time SCUBA diving, or both. It is also the first time a lot of them are expected to independently do a research project and write up/present the results. It is a great experience, and one the students truly enjoy. You can read about their excitement and adventures on the trip’s blog Tropical Blogs. You should definitely check it out.
I am a marine biologist that is currently attending graduate school at the School of Marine and Atmospheric Sciences, Marine Sciences Research Center, of Stony Brook University, New York. I am very interested in marine ecology and have been focusing my studies on bay scallop interactions with their habitats. I plan to investigate various anthropogenic impacts on bay scallop populations for my PhD dissertation. This blog will highlight the details of my graduate research, from bay scallop-eelgrass interactions as previously mentioned, to alternative habitats for scallops, such as Codium, to trophic cascades, and more. Enjoy!
Artificial Seagrass
Is a useful experimental tool to mimic natural seagrass while controlling many factors, such as density, canopy height, leaf number, which are usually confounding in natural eelgrass meadows.
Scallops seem to love this stuff!
Recent Chronicles comments