Well it has been a few weeks since I’ve posted on some research articles. But then the Journal of Experimental Marine Biology and Ecology published a manuscript about cod responses to expanding seagrass meadows. In addition, a paper out of Japan earlier this year talks about the loss of fish species with the loss of an eelgrass meadow. Combined, these point out the obvious, many finfish are dependent on seagrasses for habitat. However, its not just typical seagrass-associated species that are affected by the loss of seagrass.
First, what happens when seagrasses disappear? There is a wealth of literature that suggests disappearing seagrasses has many negative consequences for both resident and transient species. Many species, including numerous commercially important species, utilize seagrass as a habitat for at least some portion of their life cycle. A paper by Yohei Nakumura examining seagrasses next to l reefs demonstrated that seagrass loss has an impact on the abundance and diversity of fishes, including reef associated species. A series of disturbances, particularly typhoons, decimated a seagrass meadow near a reef, to the point where in 2009, the seagrass meadow had totally disappeared. This caused a 80% reduction in the number of species and a 90% reduction in the total number of individual fish along transects at the same site before and after the disappearance. In addition, they monitored a nearby undisturbed site as a reference, and there was no difference in the abundance or diversity of fishes over the same time period. Many of the fishes that disappeared weren’t just seagrass residents, but also coral dwellers. In fact, the only species that didn’t seem affected were some gobies. The reason for the loss of fish might not be the eelgrass itself, although the habitat does provide shelter from predators, but could also be due to loss of food for many of the fish – tiny crustaceans that live amongst the seagrass.
A more recent paper involves the increase in abundance of juvenile cod in areas where seagrass is recovering and expanding. First, I know what you are all thinking, I love cod and eelgrass associations! And second, it is great news to hear that seagrass is recovering in some areas (I can talk more about this later). Apparently, there are seagrass meadows in Newfoundland, Canada, that are recovering and expanding over the past decade. These habitats are nursery grounds for both Atlantic cod and Greenland cod. So, one might imagine that an increase in seagrass would be beneficial to these species. Using biweekly seines to monitor changes in fish abundance, Warren and others were able to demonstrate dramatic increases in young of the year cod in the seagrass habitats, in particularly in those “recovering” habitats. This increase also occurred rapidly with expanding seagrass meadows. This suggests that these fish are capable of recovering quite quickly if enough suitable habitat exists. However, it also suggests that since juvenile cod might respond so rapidly, that any negative changes in seagrass cover can be detrimental to stocks. Combined with the Japanese study, the literature indicates that fish populations may lack resiliency to seagrass loss, and illustrate the need for water quality monitoring and management, as well as seagrass restoration. Otherwise, the news that cod stocks might recover, might be just internet fodder.
Nakamura, Y. (2010). Patterns in fish response to seagrass bed loss at the southern Ryukyu Islands, Japan Marine Biology DOI: 10.1007/s00227-010-1504-7
Warren, M., Gregory, R., Laurel, B., & Snelgrove, P. (2010). Increasing density of juvenile Atlantic (Gadus morhua) and Greenland cod (G. ogac) in association with spatial expansion and recovery of eelgrass (Zostera marina) in a coastal nursery habitat Journal of Experimental Marine Biology and Ecology DOI: 10.1016/j.jembe.2010.08.011
Research to Assess and Tackle Issues of Seagrass Die-Off in Local Waters
Cold Spring Harbor, NY — May 1, 2009 — Seagrass has received a significant boost thanks to a $500,000 research grant (H.R. 1105, the Omnibus Appropriations Act of 2009) co-sponsored by Congressman Timothy Bishop (NY-01) and Congresswoman Rosa DeLauro (CT-03). These overlooked, but essential underwater flowering plants, form dense stands in shallow salt-water bays and harbors, and provide critical habitat for local fish and other marine life.
Read the rest here.
We all know the story here, at least if you have been following my blog, but seagrasses are vital ecosystems that serve important nursery and foraging habitats for many fin and shellfish. Many of the species are also of economic importance, which is garnering eelgrass more attention. This is big news for Long Island, since there are numerous critical gaps in the information necessary to successfully manage and restore eelgrass. And, while there may be other suitable habitats in the Peconics for my study organism, the bay scallop, eelgrass is the preferred habitat.
To learn more about seagrasses, and eelgrass in particular, check out Seagrass.LI. Also, check out this new blog by a marine biologist from Canada.
At the Cornell Cooperative Extension of Suffolk County’s Marine Environmental Learning Center works a team of eelgrass restoration experts. They have been actively working to restore eelgrass meadows to their past glory throughout the Peconic Estuary, and more recently have been working in Long Island Sound and in the South Shore estuaries. About twice a year they release a newsletter that highlights some of the work they are involved in. The current newsletter also highlights the scallop restoration project being undertaken in Suffolk County, a project which I am involved, and a project that allows me to conduct much of my bay scallop research.
to read the current newsletter.
Also, if you would like to visit their website, click here
I have worked with this group in the past, and all members are very knowledgable in habitat restoration. They have experienced success in many of their transplant and restoration sites, and even developed their own methods for restoration. Now that the importance of eelgrass for many species has been ackowledged by the state of New York, which recently held a meeting of national and international seagrass experts to create an “eelgrass task force” to identify areas of research that are important to understand the dynamics of eelgrass survivng on Long Island and how best to protect it, the job of both the Cornell seagrass restoration team and Dr Brad Peterson’s (of Stony Brook University) Seagrass Rangers, a team of graduate students to which I belong, has never been more important.
To see the seagrass ecology lab website, click here.
So anyone following my blog knows that I was actively involved in the bay scallop restoration efforts in Long Island. To refresh, scallop populations supported a vibrant fishery in NY until the mid 1980s, when populations crashed due to the first occurrence of a brown tide bloom, and recurrent brown tides pushed scallops to the brink of local extinction. The brown tide has not occurred in the Peconic Estuary since 1995 (although it still occurs on Long Island waters), so in 2006, restoration efforts started to help jump-start local scallop populations in the Peconics.
Commercial bay scallop landings and Brown tide occurrence
These efforts sought to boost spawning stock and concentrate high densities of scallops in close proximity to enhance fertilization and reproductive success. The idea was that low population densities of adults were limiting reproduction, which was subsequently limiting larval supply and recruitment. The restoration efforts sought to boost adult populations by establishing spawner sanctuaries using an array of lantern nets or by high density on bottom restoration. You can watch a number of videos on these efforts here, or watch the Fox News piece below:
The restoration efforts had been very successful – every year we see higher numbers of scallop spat than the year before (despite the same effort), and the results have translated to scallops on the bottom and to the fishery. Recently, our group was able to publish some of our findings in Marine Ecology Progress Series.
We were able to demonstrate at all sites annual increases in the mean spat per bag – that means, each year post-restoration, we saw greater numbers of baby scallops in our collectors. This occurred not only in our basins where we actively did restoration, such as Orient Harbor and Hallock Bay, but also in nearby basins with no active restoration efforts, such as Northwest Harbor.
A figure from our MEPS paper, illustrating the annually increasing densities of scallop spat in Orient Harbor. The cross denotes the site of a large lantern net spawner sanctuary.
In fact, scallop spat abundance increased up to 3000% of pre-restoration levels. This was despite that none of the environmental parameters had changed from the 10 years prior to restoration beginning to the 5 post-restoration years we examined for this study. Environmental variables could possibly influence the amount of larvae produced and larval survival. However, temperature, chlorophyll (a proxy for food), nitrogen, monthly rainfall and salinity were not different between the 2 time periods. This suggests that the restoration efforts played an important role in helping to increase the larval availability. In essence, we “primed the larva pump!”
Environmental variables for the pre-restoration period (1996-2006) and the post-restoration period (2007-2010).
Obviously, we were expecting these results and were very excited that we were able to eliminate other possibilities of increased larval supply. Additionally, the dates of peak settlement for the most part lined up with our estimates of spawning dates and settlement.
This doesn’t mean much, however, if it isn’t translating to the bottom, since we collect these scallops in spat collectors hanging in the water column. Many sources of mortality, but primarily predation, can occur from the time the scallop settles on the bottom to the time it can spawn and then contribute to the fishery. I focused most of my dissertation research on habitat and predation on scallops. Some of the cool things from that research suggests that patchy seagrass might not be detrimental to scallop populations and that an invasive species might be a suitable alternative habitat. So, despite limited seagrass in our restoration estuary, we have seen increases in scallops on the bottom.
On bottom increases in scallop densities post restoration
And in many of the basins, these increases in on bottom densities in the fall correlates with the increases in spat fall during the spring of that same year.
Relationship between seed scallop densities in the fall on the bottom in Orient Harbor and the spat per bag landings from the spring.
We are currently preparing this data for a manuscript, showing the subsequent increases in on bottom densities, fishery yield and the economic benefits of the restoration efforts. Hopefully, the success of this project and the information gathered will help other restoration efforts on Long Island, such as the Shinnecock Bay Restoration Project (which I have blogged about ) and elsewhere. I am hoping to turn some of the things I learned with this project (and the many various side projects) to my oyster work here in NC, although I also plan to keep working with scallops.
More to come, so stay tuned!
I realize that I have not made a blog post in a very long time. My apologies to any followers I still have left. Today marks the opening day of the 42nd Annual Benthic Ecology Meeting, and I figured it was as good a time as any to make a new blog post. Afterall, I have made multiple BEM-related posts in the past, and I am currently waiting for my ride to leave for the meeting.
A lot has changed for me since the last benthic meeting. I completed my dissertation and relocated to UNCW to start my post-doctoral career. It has been pretty hectic. When I first came down, I was trying to finish up some manuscripts from my dissertation, like the chapter on the impacts of Codium fragile on scallop demographics such as growth rate and tissue condition. My conclusions were that the invasive alga might be beneficial for scallop populations, especially in the absence of their native habitat, seagrass. I have made this argument before, and this chapter was recently published in Marine Biology. Other chapters haven’t gone through so smoothly and are still being reviewed, but that is par for the course in this field.
I was balancing those with editing other manuscripts from collaborative efforts with my former lab and one of my committee members. I also made two failed attempts at doing a laboratory study with oyster spat and an ectoparasitic snail. The results were promising, but I kept having high mortality across all treatments, and I need to come up with a better way of maintaining and feeding the oysters in a lab setting. I also have now written 4 proposals to various funding agencies, and am currently working up some old data sets for my current lab. Within all this, I crammed a 2.5 week trip to Jamaica to attempt to do some sponge work, but the weather didn’t cooperate (well, not with me anyway, my stomach is not the biggest fan of the ocean). Suffice it to say, I have been extremely busy, but that isn’t really an excuse to have stopped making regular updates. However, I have only been in “the field” once since I relocated, and it’s not very much fun writing blog posts about writing Sea Grant proposals.
However, this will be a nice little break, and I am excited to be headed down to the meeting. There are a lot of talks this year that promise to be very good and informative, plus there is also the Beneath the Waves Film Festival which is always excellent. And, in general, I like to see former colleagues, friends, potential future collaborators and have a generally good time drinking beer and talking all things marine science.
My talk this year will involve some work from my former lab on multiple predators. Natural communities have multiple predators foraging on shared prey resources, and until the last decade or so, these interactions were largely ignored in lab studies. They are interesting, because the consumption of prey is rarely additive – that is, two predators do not typically consume the same amount of prey you would expect based on how much they can eat when they are alone. More often, the prey either experiences reduced or enhanced risk relative to expected consumption. For crabs interactions, which utilize prey and habitats similarly, we expect that antagonistic interactions increase, resulting in reduced risk on the prey. Check out this video:
What you can see is the smaller crab is like your annoying little sibling who just won’t leave you alone and constantly antagonizes you. It kind of makes you stop what you are doing. In crabs, this means they might stop foraging to deal with each other. This usually means that the prey survive better than would be expected. However, this isn’t always the case when you run the trials and do the statistical analysis:
Proportion of ribbed mussels consumed by Hemigrapsus alone (pink bar), by Carcinus alone (green bar) and the two crabs together (gray bar). The circle denotes the expected consumption.
In this case, our observed consumption was not different than we expected, based on individual consumption rates. We anticipated to see a risk reduction, and based on the video, we know the crabs were interacting. So what gives? Upon further inspection, when we looked at the sizes of mussels consumed, we saw a dramatic shift:
Pink bars are mussels consumed by Hemigrapsus, Green bays by Carcinus and gray bars by both
What we saw was that when foraging along, the green crabs consumed all the size ranges that were offered, but when foraging together, they shifted to selecting smaller prey, possibly because they had less time to forage. So while the overall proportion being consumed stayed the same, they were foraging on a smaller portion of the population. We thought that was pretty cool!
Stay tuned for more posts, I promise to do better!
As you may have noticed on my last post, I am now down in UNC Wilmington working as a post-doctoral research associate. I have been here about 2 weeks, but most of my time has been reading and writing. Luckily, yesterday I was able to get outside into the sunshine and get into the water. Well, mostly into the water.
I went out with some of the hatchery crew down at the Center for Marine Science . We were looking for broodstock scallops for spawning in the hatchery. Scallops in North Carolina spawn usually twice a season – once earlier in the summer and then once again in the fall. So we went out to collect some. Now this is different from any of the times I went searching for scallops in New York , where we would do surveys and collect scallops via SCUBA. Down here in North Carolina, we find a spot at low tide and just crawl around on our hands and knees and feel for them. It might not sound efficient, but with all the river input and soft bottoms, you can’t really see anything if you had a mask anyway.
But it was cool and totally refreshing to get out of the office. And we were a little successful, finding almost 100 scallops to bring back to the hatchery. The site was interesting, it consisted of small marsh islands and oyster reefs surrounded by patches of seagrass, which was Halodule wrightii, also known as shoal grass. It is very short, so it doesn’t seem like the ideal seagrass for bay scallops, which typically use seagrass as a spatial refuge from predators, and yet, in my qualitative assessment, most of the scallops were found in the seagrass. There was lots of life around these islands, most of which we could not see. But here were a few stingrays, and some other assorted fish that we couldn’t get a good look at, hermit crabs, lots of oysters and clams, and lots of tulip shell snails. Of course, I grabbed few specimens for my collection.
When we returned, we had to clean the fouling organisms off the scallop shells, which consisted mostly of Crepidula sp. and oysters, with some tunicates thrown in.
All in all, it was a good day, and nice to be out of the office for a change. Hopefully, we will use some of the larvae and juveniles for a number of flow speed experiments. I can’t wait to get out in the field again and start some experiments.
Yes, I am back. After a looooong hiatus, I am finally back to blogging! (no, seriously, hold your applause). I had been pretty busy the last few months with writing, defending and editing my dissertation (John M Carroll Dissertation). But that is all over now! Defense was successful, edits completed, graduate school accepted, and as of August 16th, I am officially a doctor! So I am hoping that now, I can now get back to writing posts more regularly. I am starting a new position, a post-doc with Dr. Chris Finelli at UNC-Wilmington in the MarBEL (Marine Biofluiddynamics and Ecological Lab) lab. This will be a relatively new field for me, so I am looking forward to learning new methods and working with new people. In fact, I am in Wilmington right now and will be officially starting my position next week – so more to come on that.
The Need to Restore Shinnecock Bay from Christine Santora on Vimeo.
But I wanted to make a post today talking about something from my recent past – the Shinnecock Restoration Project (ShiRP). I was involved in preliminary research and monitoring for this project the past two summers, so I am very excited about the big news – $3million dollar donation to restore Western Shinnecock Bay – an area degraded by eutrophication and overfishing and hampered with recurrent harmful algal blooms. This confluence of factors, and likely including other factors such as distance from larval source, has led to shellfish populations in the western portion of Shinnecock Bay extremely low. This is problematic, since the lost shellfish – mainly clams and oysters – are filter feeding organisms and thus act as natural filters for the water column. As their numbers dwindled, water condition worsened, eelgrass cover decreased, harmful algal blooms increased, which affected recruitment of new bivalves to the western bay – a term called a feedback loop. However, restoration has worked to successfully bring back scallop populations to the Peconics – another New York estuary – so there is a lot of confidence that restoration will work in Shinnecock Bay as well.
I am very excited for my colleagues back at SoMAS for this project. The general plan is to combat the decreasing water quality by significantly boosting shellfish populations – on the order of millions – in spawner sanctuaries within the western bay. The idea is that these bivalves will serve two purposes. First, they will increase the filtration capacity of the western bay, removing plankton and thus nitrogen, from the water column. Second, these high density aggregations will have enhanced fertilization success and act as new larval sources, pumping millions more baby shellfish into the bay. Last fall, I was able to be on a trip that planted ~500,000 seed clams into the bay. I was also involved in investigating the growth of seagrass transplants from sites with varying water quality at different sites along the water quality gradient in Shinnecock Bay to identify the most hardy population that could withstand poor water quality in the western bay. This information will be used for the second phase of the project, which is eelgrass restoration.
This past summer, in addition to continuing the spat monitoring which I started in 2011, I also did a hard clam suction survey to give us a baseline idea of clam densities in the western portion of the bay. This was fun – suction sampling for hard clams also turned up all manner of organisms – mussels, razor clams, soft-shell clams, lots of crabs and even some moon snails. But most importantly, we were counting and measuring hard clams, a target fishery species and also a target species for this restoration project.
Plus, I also got to learn a little bit of GIS to make maps of distributions, like this one: (I had to remove the map for fear clammers might go to the sites)
The ultimate goal is to restore the water quality, enhance bivalve and eelgrass populations, and enhance local fisheries. I am very excited for this project, and I hope that when I return to Long Island in the future, this academic-public-private partnership will be a highly successful restoration effort. Most importantly, Shinnecock Bay might be perfectly suited for restoring water quality via shellfish enhancement – it is a relatively shallow estuary system (<2m deep except for in the navigation channel which itself is only ~3m deep). Thus, this shallow water body could effectively be filtered by high densities of the shellfish which this project aims to restore. Unlike other much deeper estuaries where the shellfish might not be capable of such an impact, Shinnecock Bay is best suited for this endeavor. Good luck to my friends and colleagues involved with ShiRP!
The Peterson Lab Family. Photo by Rebecca Kulp
So I spent the last few weeks attending conferences (and, actually leave Sunday for another one). First, I spent time in Norfolk, Virginia, at the Benthic Ecology Meeting. While there, I saw many good presentations, and learned many new things. First, I learned that my former student Kate Lavelle (well she was an undergrad who worked on my project), who is now completing her Master’s work at the Harte Research Institute at Texas A&M Corpus Christi, gets to do awesome things in submersibles! I went to a bunch of talks regarding trophic ecology – including ones about predation as well as non-consumptive effects, and luckily my talk was on the first day in the Trophic Ecology session. I talked about using back of the envelope calculations to get an idea whether or not we would expect to see scallops on the bottom based on predator density and habitat complexity. I think it went well. But the one thing I took home from that talk was hope you don’t have to talk at the same time as Emmet Duffy, as it is my understanding that about everyone else at the conference was at his presentation. I saw a couple of cool talks about species interactions and their importance in the context of ocean acidification, including one by my labmate, the illustrious Amber Stubler. I also saw a very interesting talk by Paul Gribben from Australia about a species of seagrass which actually leads to enhanced predation on clams. Weird! I also attended plenty of seagrass and restoration talks. And of course, the Film Festival, which you can watch all the videos here.
Then I headed to Seattle for the National Shellfish Association meeting. That was pretty good as well, but between 3 days of talks previous to that and the jet-lag from flying across the country, it was hard to absorb any information. I was able to catch a few interesting plenary talks, including one by Ray Hilborn and another by Bruce Menge. Otherwise, I went to a lot of restoration talks, most of which focused on oyster reefs, which were useful since it seems like I might be doing some of that this summer in Shinnecock Bay. There, I essentially gave the last talk of the conference, about multiple predators and impacts of habitat complexity, which I think went well. I also learned that Seattle is very hilly, more-so than I would have imagined, but it also has a really awesome bar called the Taphouse Grill, which had 160 beers on tap! Overwhelming! But all in all, a good trip.
Now, I have to prepare my presentation for the United States chapter of the International Association of Landscape Ecology meeting in Newport, Rhode Island, which I give next Monday morning! Uggg! Why did I think it was a good idea to give 3 different presentations at 3 different conferences in a 3 week span? I guess it’s kind of my going away party, as I am planning on graduating this summer. July defense!
So we landed in Jamaica this afternoon. When we left New York it was below freezing, and when we arrived in Jamaica it was over 80 Fahrenheit, so that was a nice change. It was about an hour (exciting) bus ride from the Montego Bay Airport to the Discovery Bay Marine Lab, where we will be staying for the next 17 days. We took a little tour of the facility, had excellent dinner, and then met with the class to go over the syllabus. It is intense. We essentially are fitting a 3 credit course into 2 and a half weeks, and the next 4 days are going to be intensive lectures, because the meat of this course is in student run projects and experiments, so we want them to have as much time as they can get to work on data collection. So, I am trying to squeeze a basic intro to ecological thought into 100 slides for my lectures tomorrow (haha try that!), so that the terms we will used throughout won’t be foreign to the students. Then, I am giving lectures on marine algae, coral reef fish ecology, seagrasses, mangroves, and food webs. Within the next 3 days. So yeah, I’ll be as busy as the students.
We’ll be going snorkeling tomorrow, so stay tuned for pictures of that. Well I hope. Internet here is slow and spotty, so most of my pictures will likely have to wait until I make it back home. But I can’t wait to use my home made slurp gun, aka yabbie pump, to try and catch marine critters (you can watch a build your own video here). Yes!
The RV Peconic, aka "Jungle Queen"
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.
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.