So I have returned from Jamaica, which ended up a pretty cool trip. Unfortunately, the internet was slow and made loading images difficult, so I wanted to put another few photos up from my trip before I start talking about my research some more in the coming months. Good news, manuscript reviews came back, and were pretty positive, some moderate changes and it should get published. Another manuscript is getting ready for submission, and I am starting to get stuff written. But before I go on about that sort of thing, just enjoy these new photos from diving in Jamaica!
Lets see, Thursday we went to the Dunn’s River Falls as a break from the daily grind here at the marine lab. That was a lot of fun.
Bottom of the falls
Look at me!
Then in the last 2 days I have put in 7 dives, 4 outside the reef and 2 in the lagoon and one on the other side of Discovery Bay. I have seen many cool things, collected cool shells, so its been pretty fun. I had some issues with my camera at the Rio Bueno dive yesterday, so my pictures didn’t come out so well, although I was lucky to get a few shots.
Today we did 2 dives on the fore-reed and 2 within Discovery Bay. Outside the reef I logged over 2 hours of bottom time, and took many, many pictures. More anemone shrimp, lionfish, gastropods, and lots more. Enjoy!
So yesterday was a little rough… I mean the weather wasn’t terrible, but there was still some swell from the days of wind previous. So during our safety stop, I was feeling it a little bit, so I only did the one dive and took an early boat ride back.
Today, sea was almost like glass, did 2 dives outside on the fore-reef, and then one inside the lagoon. Saw some cool things – invasive lionfish, big schools of creole wrasses, bluehead wrasses, giant queen cocnh, and lots of other fish. However, this site was fairly impacted, so not so much live coral as the reef I saw yesterday. Oh well. Was still fun to get 2 dives in outside and not feel like total crap. And diving in the lagoon was cool, despite it being so shallow, it was nice to be able to lay down and just look. In the lagoon, we saw inking sea hares, a peacock flounder, yellow ring sting ray, little crabs, another sharptail eel, spiny lobster, and lots more fish. So cool.
I haven’t loaded my pictures from today yet, but I’ll leave you with a few more photos from earlier in the week/weekend.
So we have been extremely busy since we arrived. We have essentially crammed a coral reef ecology class into 4 days, which was overwhelming for the students. Their practical exam is this afternoon, so they are all cramming and freaking out a little bit. I have tried to quell some of their anxiety, but at least by this evening, the lecture and exam portion of their class will be over. In between lectures, we have been snorkeling, and today I did my first dives since arriving. So that’s good. The students will start their projects tomorrow, and have ~1.5 weeks to conduct a research project. The weather (wind) hasn’t been very good, so hopefully we get more dive opportunities, but the lagoon has been pretty cool.
Some things I’ve seen:
More photos to come, but internet here is incredibly slow so I am having a hard time uploading. But, you should check out the student run blog to see what they have been seeing/doing as well.
So I am sure that everyone has been posting ad naseum about Hurricane Irene. I don’t want this to be another such post. However, I did want to share some video and photos from the east end of Long Island, particularly Hampton Bays (where I live) and the Stony Brook-Southampton Marine Station.
Despite all the warnings and conjuring up memories of the 1938 “Long Island Express”, Irene came through Long Island early Sunday morning as a high tropical storm, bringing 60-70 mph winds and lots of rain to the Island. However, it also crossed at high tide on the same day as a moon tide (so already higher than normal). So there was some damaging storm surge, although less than originally forecast. We got off relatively lucky out on the east end, with what appeared (at least to me) as limited damage (although we are due for a big one).
The following is a video and some photos from the marine station which I took Sunday morning around 11 am (~3-4 hours after the hurricane crossed Long Island and ~3 hours after high tide):
There was considerable damage to Montauk Highway where it runs next to Shinnecock Bay at Swan Beach:
The town dock on Little Neck Road, down Old Fort Pond from the Marine Station was lost:
Jackson’s Marina was devastated:
Even the canal flooded and had large waves running down it:
All in all, it was not as bad as it could have been, at least out by me, and it did bring with it one surprise – a pelican!
This post is not intended to say that we got it bad out here – quite the contrary. The real damage seems to be where the torrential rains turned into massive floods in NY, NJ and Vermont. Thoughts and prayers to all those who are affected in those areas.
One of the reasons I love diving is that you see something new almost every time you go out. Even in the Peconic Estuary in NY, where I must have logged literally hundreds of dives, I still find something exciting every time I go out. Maybe it’s the scientist in me. I was out diving yesterday (Wednesday) at one of our on bottom restoration sites. As my dive was finishing up, I decided to poke around a little, since I brought my camera today, unlike last time out. As I was swimming around on the bottom, I came across this knobbed whelk (aka, the knobby conch!), Busycon carica, which is apparently the both the Georgia and NJ state shell, go figure.
This isn’t new for me, I see these all the time. However, this guy was turned upside down. Upon further inspection, it was clear that this guys was dead and being eaten.
Unfortunately I couldn’t see what was doing the damage, but I have some ideas based on some clues and what I have seen in the past. When I looked at the shell, it was apparent there was a hole punched in the whorls near the spire or apex of the shell. This is something I commonly see in whelk shells.
SO what do I think is happening? Well I haven’t seen it happening first hand, but based on observations I have made diving way back in the spring of 2009. Crabs. Specifically, though, I am thinking spider crabs. It’s funny, because I have never seen the act of cracking the hole in the shell. But the only crab I think capable of doing this, with the design of its claws and legs, is the spider crab. I have pictures of crabs holding onto the hole and eating the whelk. I am convinced it is spider crabs. So what’s happening? I am not 100% on the anatomy of the whelk, so I had to look it up. The columella is the central axis inside the shell. The whelk attaches to the shell by the columellar muscle, and it uses this muscle to retract its foot and head inside its body. It then closes with the operculum. In order to pull the body out from the shell, this muscle needs to be cut. According to this website, by poking a hole in this spot on the shell, the columellar muscle can be separated from the shell, and the body of the whelk can then be accessed and removed. This is what that whelk looked like when I pulled it from its shell. (Don’t ask me for an anatomy lesson here, the website above does a good job).
I don’t know how long it took us to figure this out, but my guess is that spider crabs had this figured out a long, long, LONG time ago.
I do recognize that there is also a flat-clawed hermit crab in this photo, however, the claw anatomy isn’t such that I think its capable of hole punching. I think spider crabs, at least Libinia, are typically considered scavengers, however, I have frequently observed them in the field eating bivalves. My guess is that they are very capable predators of very slow moving prey. And while it might not make too much sense for a crab to waste its time punching a hole into a whelk whorl, the reward is likely great (these things are big!). So it might be an optimal foraging thing. Although I don’t know too much about spider crabs and diets and carbon equivalents of potential prey, so I don’t want to get too carried away. I mean maybe it’s just because variety is the spice of life – why eat algal detritus every day when you can eat scungilli?
Ok, so maybe not the MOST exciting thing in the world, but I thought it was an interesting observation. Go ahead and look for whelk shells. I bet many will have these holes in the whorls near the apex. My intuition tells me this is spider crab damage, but I’d love to hear your take on this observation.
New species get introduced into novel habitats almost like clockwork in the modern era. These are termed introduced or exotic species. Typically, these introductions are the effect of anthropogenic activity. Sometimes, these species become nuisances – spreading in their new habitats via natural processes, and creating problems for native species. These nuisance exotics are called invasive species.
So how do they get here? From a variety of ways, but perhaps most famously via ships’ ballast dumping. Ballast is simply material used by ships to control and maintain buoyancy and stability. Typically this is water, pumped into ballast tanks from the port the ship is sitting in at the time. This ballast water gets pumped in or out depending on the weight of the cargo on this ship, and so you can imagine how water could be transferred across whole oceans, bringing with it any species that happened to get sucked in to the ballast tank. This is a major source of marine invaders – including the now infamous zebra mussel, Dreissena polymorpha, which has become especially problematic throughout fresh waters of the Mississippi River, the Great Lakes, and the east coast. However, invasives can also come from aquaculture gear and species – especially as native species are fished out and replaced with non-natives to keep up food production. In addition to these non-native species used in aquaculture, other species hitch rides on them.
How Ship's Ballast works
However, as you can see above, it is possible that all invasive species are not created equal – that is, maybe not all invasives are so bad. Green fleece, known as Codium fragile, has been introduced to the east coast of America for decades. Originating from Japan, it has typically viewed as bad – it is a buoyant species which needs hard substrates to attach, including living shellfish. It got the nickname “oyster thief” since it would attach to oyster shells, and whenever a storm or strong current event occurred, the buoyant macroalgae would be swept away, dislodging oysters and taking them away from reefs and culture sites. It is clear why this is considered a problematic species.
And yet, some recent research has shown that maybe Codium isn’t all that bad. Research which I have participated in has demonstrated that Codium may act as a viable alternative habitat for native bay scallops. Why? Bay scallops have evolved a strong association with seagrasses, and the Codium canopy likely provides the same upright structure to scallops. We observe scallops frequently in association with Codium in Long Island bays, and a study conducted showed that survival of free-released and tethered scallops was the same in eelgrass and Codium, suggesting that the invader offers a similar predation refuge. This was published last year in Marine Biology (See Carroll et al, 2010, below).
From Carroll et al 2010
In addition, I have taken the research further. The aforementioned paper talked about survival on a relatively short time span – 1 week. In order to examine the longer term effects on growth I conducted a caged field experiment the past two summers at 2 field sites with eelgrass, Codium, and unvegetated sediments in close proximity to each other. The general findings have been that scallops in Codium grow at rates similar to scallops in eelgrass, however, there are site-specific differences. There are also no differences in mortality between the habitats – suggesting that dense stands of Codium aren’t having as detrimental impact of low dissolved oxygen as I originally thought. This work isn’t published yet, as I am working on a method to find the stoichiometry of the tissues, but some of the results are in the presentation I gave at CERF 2009 here: Thursday_SCI-045_1115_J.Carroll
Moon snail crawling over Codium
However, I am not the only one who sees “positive” impacts of Codium. In the most recent issue of Marine Ecology Progress Series, a team of Canadian researchers, led by Annick Drouin, higher abundance and diversity of the faunal community in eelgrass meadows invaded by Codium fragile. Using a variety of sampling methods and field manipulations, the team demonstrated higher abundance and diversity of invertebrate organisms on Codium, and in eelgrass meadows invaded by Codium, than those without Codium. The pattern of fish abundance and diversity was not different – likely because they are highly mobile and can move easily between structured habitats. It is likely that Codium just generates MORE habitat, as it is branching and canopy forming. The important thing here is the ecological implication – the lack of a negative effect on native species by the presence of this “invader.” Perhaps Codium might not be so bad after all, especially as eelgrass is declining in many regions.
Figure from Drouin et al 2011
It is possible, then that “invasive” vegetation species in the marine environment may not always be bad. In many cases, invasives may be beneficial. Numerous studies (including the ones above with Codium) have demonstrated a positive effect of invasive algal species on native fauna. Typically, the vegetation is habitat forming, and invades areas where native habitat forming vegetation has already been lost. In essence, it is replacing a lost habitat, and creating a new habitat which is functionally similar to the species which declined/disappeared. That being said, invasive algal species can be detrimental to native macrophytes through competition. However, the benefit is in enhancing native fauna, which has potential fisheries ramifications. This requires further investigation, but it is entirely possible that non-native macroalgal species might have a positive effect on a number of native fauna.
Mud crab in Codium canopy
Pipefish chillin' in Codium canopy
The above photos, and the one of the moon snail farther up the page, are all illustrations of native species of Long Island associating with the invasive Codium fragile. Now, again, there are certainly detrimental effects of invasive species, so I am not trying to be too much of an apologist for them here. However, in the absence of eelgrass, it is entirely likely that the upright, canopy forming structure of Codium creates a habitat suitable to many seagrass associated fauna. As eelgrass is declining, invasive macrophytes might be important replacement habitats for a variety of native species. Understanding how these species affect native species will be key for management of estuaries moving forward. Particularly, once established, invasives becoming increasingly expensive and difficult to remove. If some invaders might be of benefit, that relationship needs to be well understood. Hey, invasives could help bring back the bay scallop in NY (and likely is having an impact), providing a habitat as eelgrass has disappeared from many Long Island areas. Who knows where else they might be beneficial.
There will be those of you out there who disagree. I don’t blame you. Calling an “invader” beneficial certainly goes against conventional wisdom. When we first introduced the idea of Codium as a potential scallop habitat to a shellfish crowd, we were scoffed at. However, the data don’t lie. And more research points to cases where invasives may actually facilitate natives.
Drouin, A., McKindsey, C., & Johnson, L. (2011). Higher abundance and diversity in faunal assemblages with the invasion of Codium fragile ssp. fragile in eelgrass meadows Marine Ecology Progress Series, 424, 105-117 DOI: 10.3354/meps08961 Carroll, J., Peterson, B., Bonal, D., Weinstock, A., Smith, C., & Tettelbach, S. (2009). Comparative survival of bay scallops in eelgrass and the introduced alga, Codium fragile, in a New York estuary Marine Biology, 157 (2), 249-259 DOI: 10.1007/s00227-009-1312-0
The premise of the article states that scientists in New Zealand are using artificial seagrass to help boost fish stocks. Seagrass is an extremely vulnerable marine habitat, with worldwide losses. In some places where lush underwater meadows used to exist, the grass has been replaced by barren sediments. This can have an impact on fish stocks, as many marine species utilize seagrass as a habitat for at least some portion of their life cycle. So it comes as no surprise that scientists want to try to replenish fish stocks by enhancing seagrass. This is apparently what they are trying to do in a bay in New Zealand. Although, I imagine that the researchers are actually using ASUs to test affects of fragmentation on local fisheries species and not to actually be used to enhance species, it is interesting none-the-less.
I have a certain affinity for all things fake seagrass. Why? Well, a portion of my dissertation research involves using artificial seagrass units (ASUs) to investigate the impacts of patch size and shape (perimeter, area, and P:A ratios) has on scallop recruitment, survival and growth. As I mentioned already, seagrasses are important habitats, and bay scallops have long been known to associate with seagrass. Scallop populations are currently undergoing varying degrees of restoration (depending on location) but with restoration comes certain issues – namely, how are these little guys going to be affected by declining seagrass. In many areas where scallop populations crashed, seagrasses have also diminished in extent. Since seagrass is important for scallops, a decline in seagrass cover can have implications for scallops and their restoration. For my work, I use 2 sizes of seagrass mats, 8.5 and 17 square meters, and 2 shapes – a circle and 4 pointed star to maximize perimeter. Just in case those numbers don’t mean much to you, the small circles are just over 3 meters in diameter, the large circles around 5 meters across. The large star is 7 meters from tip to tip. These ASUs have 500 shoots per meter, consisting of 4 blades of polypropelene ribbon. It was quite the undertaking, and required many beer and pizza nights for fellow grad students, as well as help from local schools and scout troops.
I have generated some interesting, and unexpected, data. There is a wealth of literature out there about the impacts of fragmented seagrass habitats, patch configuration, edge effects, etc, that has been accumulating over the last 15 or so years. Going into the experiments, I had a pretty good idea about what I would expect to see – more scallop recruits along the edges of the mats, but higher predation at the edge. Growth to be slowest in the centers of the mats, etc. However, not everything happens the way I planned or anticipated. In particular, I have been working up some of my recruitment data, and I did not see a “settlement shadow” or edge effects due to predation. What is a “settlement shadow?” Essentially, bivalve larvae can be assumed to be passive particles, moving at the mercy of the currents. As a current comes into a seagrass meadow, the flow is attenuated. Particles settle out along the edge, and become diminished with distance into the meadow. Hence, recruitment is expected to be highest along the edges of seagrass meadows (and, also, the edges of my ASUs). On the opposite end of the spectrum, survival is expected to be the lowest along the edge, since predators are likely to have more access along the edges, and thus predator encounter with scallops should be higher. However, this isn’t what I saw. The reason? The dominant predator in my particular system is a small mud crab – not likely to be impeded by seagrass structure and essentially ubiquitous throughout the ASUs. This tells me the dominant process structuring post set scallop communities on my grass mats is predation, and the predator is apparently not impacted by fragmentation. This could have implications for restoration. I haven’t finished all the analysis yet, but it was pretty interesting. I just presented some of this work at a graduate symposium last week, and plan on presenting it again at the National Shellfish Association annual meeting in March.
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.
Occasionally I find myself musing at Memoirs of an Underwater Photographer, mainly because some of the photos Suzy Walker takes and uploads are absolutely incredible. Semi-regularly, she does a post on Fridays called PhotoFriday. This past week, the gallery by photographer Suzy Walker was entitled “Trees” and consisted of a series of photos she shot while diving around mangroves in Indonesia. I am totally jealous. One, obviously, because she traveled to Indonesia for these shots. But I am also jealous because I wish I could take photos of that caliber. Granted, she uses much better equipment than mine, but still. But it did remind me of some attempts of mine at mangrove photos. So enjoy my “PhotoSunday!” By the way, I’ve added some of these photos to the photo challenge on Memoirs. There are over 300 entries but mine are 306 (New Life), 307 (Cardinals), 308 (School) and 309 (In and Out). If you like my photos or want to check out those posted by others, go here, and vote!
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!
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!