Timing is Everything: Fish, Wildlife, and Timing of Life Events

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Timing is Everything: How Fish and Wildlife are Responding to Climate Change Through Shifts in the Timing of Life Events

Changes in phenology, or the seasonal timing of recurring life history events such as breeding, feeding, and movements, have emerged as a primary indicator of species’ responses to climate change. In terrestrial environments, shifts in phenology have been well documented; for example, earlier onset of spring and advances in the timing of emergence, flowering, and arrival times of migratory organisms have all been observed. Far fewer examples exist that provide direct evidence for climate-induced shifts in marine phenology. This presentation summarizes the current state of knowledge for shifts in phenology (or lack there of) across the Gulf of Maine, a region currently experiencing rapid and intense seasonal and annual warming. Results highlight the findings of an interdisciplinary regional working group focused on the Gulf of Maine ecosystem, and species-specific case studies including the spring spawning migration of anadromous river herring, and seasonal prey availability to colonial nesting seabirds across the Maine Coastal Islands National Wildlife Refuge. The ecological and socioeconomic implications of these shifts and potential adaptation strategies were also discussed.

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Length: 00:59:16

Location Taken: US

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Amanda Cucchi, U.S. Fish and Wildlife Service
 

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Amanda Cucchi: [0:05] Welcome remotely from the US Fish and Wildlife Service's National Conservation Training Center in Shepherdstown, West Virginia. My name is Amanda Cucchi. I would like to welcome you to our webinar series held in partnership with the US Geological Survey's National Climate Adaptation Science Center.

[0:23] Today's webinar is titled "Timing is Everything -- How Fish and Wildlife Are Responding to Climate Change Through Shifts in the Timing of Life Events."

[0:30] We are excited to have Michelle Staudinger from the Northeast Climate Adaptation Science Center and Adrian Jordaan from the University of Massachusetts-Amherst with us today.

[0:42] To introduce our presenters today, we have David Reidmiller, Acting Director of the Northeast and Southeast Climate Adaptation Science Centers, who will do the honors to start us off and introduce today's speakers.

David Reidmiller: [0:55] Thanks, Amanda.

[0:56] First off, we've got Michelle. She is the science coordinator of the Department of the Interior's Northeast Climate Adaptation Science Center an adjunct faculty at the University of Massachusetts-Amherst.

[1:09] She received her BS in marine biology and environmental science from Boston University, her MS in marine and atmospheric science from Stonybrook, and her PhD in marine science and technology and natural resources conservation from UMass.

[1:22] Michelle contributed to both the 2013 and 2018 National Climate Assessments, where I had the pleasure of working with her. Her research interests seek to understand how climate change, fishing pressure, and other stressors impact marine and coastal fish and wildlife and to develop adaptation strategies to reduce risk and vulnerability.

[1:42] Adrian is the director of the Gloucester Marine Station and an associate professor of fish population ecology and conservation in the Department of Environmental Conservation at the University of Massachusetts-Amherst.

[1:54] His research employs quantitative modeling and statistical approaches to understand ecological patterns and life processes in marine, near-shore, and freshwater systems. He's particularly interested in the links between ecosystems, the services they provide, and resource management.

[2:11] A critical part of this research focus is the engagement of fisheries practitioners and other stakeholders and managers towards finding the "sweet spots" where science can advance sustainability and enhance access to resources.

[2:24] With that, I'm happy to turn it over to our presenters and look forward to the presentation.

Dr. Adrian Jordaan: [2:30] Thank you so much, and good afternoon, everyone. I'm really excited to have this opportunity, and so I'm going to get right to it.

[2:38] The first thing is I [inaudible] talking about phenology. I realized that I haven't really defined it, but it's in our title. Phenology is this changing in the timing of life events. With that, I'm going to start moving through this.

[2:55] I'd like to ask everybody, how do you know spring has arrived, knowing that a lot of you are further south than us here? You're acting like, "That happened a long time ago." For us, it's just happening up here in the hills around Amherst in Massachusetts.

[3:09] In fact, I was going over this talk briefly this morning and I looked out my window, and this is what I saw, a little bug sticking on the window.

[3:16] It is really the case of terrestrial systems where there's [inaudible] and other plants, and blossoming flowers and the fiddleheads that are poking their little heads out of the soil right now. Where you can just look and see the changing phenology of the terrestrial landscape.

[3:34] Oceans are far more complicated. They are essentially invisible. In fact, if I ask you, "What time of year was this picture taken?" It might be hard to discern. With the exception that it's in Maine, and probably if it was winter, there'd be some white on those peaks in the distance.

[3:56] It's the case though that the ocean is very difficult to observe. We're very fortunate to have satellites that can record sea surface temperatures. In this case, they've taken color differences and used it to show where there are blooms of phytoplankton occurring.

[4:13] Mostly along shallow banks and along the shoreline, being driven by the fact that the light can penetrate to the bottom and enhance the growth of small, mostly unicellular and small multicellular phytoplankton.

[4:30] Fish, however, are very different. John Shepard said that managing fisheries is hard. It's like managing a forest in which the trees are invisible and keep moving around. I think that this is just the inevitable reality of working in the ocean ecosystem is the fact that it's really difficult to observe these things, but it's really important.

[4:53] There are real consequences to these. Everybody, I think, is aware that there are specific seasons. Those seasons can bring on things like the turtle stranding season, which has important climate links.

[5:07] Also, we know that there are fishing seasons. There's a time that you can go to Maine or sometimes you can go to Maine, this year was a particularly bad year for ice fishing, but there's a season for that. There's a season where you can go and catch stripers or striped bass on the coast and other fish.

[5:25] We know intuitively that there are seasons, but these seasons are changing. They're different than they have been in the past.

[5:34] Another example and very contemporary, if you look at the date here is April 27, just a couple of weeks back, or week or so back, where there's a fixed gear closure area within the Cape Cod Bay, to protect endangered right whales. There are adaptive management strategies in place to make adjustments to this timing based on the presence of those whales.

[6:01] On April 27th, the restrictions were extended, but three days later, on April 30th, they were rescinded, because the whales had moved on. It's important to realize that there are real consequences to these seasons, and to the fact that they may be changing in terms of the organism's response. That those are going to impact in our activities on how we interact with those organisms.

[6:30] It's also really important to note that those organisms in the ocean are interacting with one another, just as they do in the terrestrial ecosystem. That the changes in one species are going to have impacts on other species. That's ultimately what we're very interested in, and it's going to be a major focus of this talk.

[6:47] I'm going to introduce the rest of our work on phenology by focusing on the synthesis article that Michelle led. I'm going to focus this mostly involved in the Gulf of Maine which hopefully, you can see my cursor is this enclosed bay essentially, with these banks, Georges Bank and Scotian Shelf on the outer edge.

[7:11] This area is warming. Especially, in the past 10 to 15 years, has experienced rapid warming compared to the rest of the global oceans. That warming is occurring on a highly seasonal system.

[7:27] We anticipate that there will be changes in those organisms. As they respond through their activities over those seasons, because their activities take advantage of specific conditions within the Gulf of Maine and within different parts of the Gulf of Maine. To either undergo foraging, or breeding in the case of marine mammals and seabirds, or spawning in the case of fish.

[7:53] That warming, because it's working within the seasonal cycle, it's changing the way that the seasons are operating. What we have here is a figure showing the spring transition date moving two weeks earlier.

[8:11] Just very briefly, the spring and fall transitions are those dates at which the temperature crosses the long term average for that region, so essentially marking, in the spring, the point at which for the rest of the year it'll be warmer than the average. Then, in the fall when it becomes colder than the average for the "winter," in whatever region you're looking at.

[8:37] This transition is occurring earlier in the spring and later in the fall, such that the entire summer duration is increasing, and obviously, the winter duration is decreasing. We know that this is going to have important effects.

[8:52] It's not quite as simple as that just sunlight hitting the ocean and warming it up. The ocean is a complicated area with a lot of oceanographic and climate forcings.

[9:03] Some things we're going to talk about today that are important to mention right now is the Gulf Stream has an important influence in how close it is to the coastline, by influencing water that can enter into the Gulf of Maine.

[9:15] We also have important effects of the North Atlantic Oscillation, which is essentially the descriptor of climate patterns across the northeastern United States, which can influence the ocean directly, but also influences patterns in precipitation.

[9:28] This is an entire talk in itself. I'm just going to leave it there by saying that these responses are going to be complicated by broad-scale climatic and oceanographic processes, and by the fact that these organisms all interact with each other within a food web.

[9:43] This is a food web model that was developed by my graduate student, Bea Diaz, looking at and specifically the Gulf of Maine region. I love this figure because it shows how interconnected these parts of the food web are.

[9:58] As energy flows from low in the food web, up through these small invertebrates, mostly through what we call our forage fish, and up to species like cod, and haddock that we fish. As well as important organisms like sea birds and other marine mammals.

[10:14] Then of course, our fisheries which are a really important part of a state like Massachusetts, but really any coastal state.

[10:24] These complex interactions then, it shouldn't be surprising that the responses are going to be complicated.

[10:31] In our synthesis, we did a thorough literature review, and we found about 20 cases where we could detect a change in a species phenology.

[10:41] Obviously, we anticipated that the responses would follow what you would see in this line H of the bottom if there's a shift in the seasonal transition, but that is not the case. In fact, what we see is a mixed response across different species and a difference in that response in terms of the magnitude.

[11:02] We're worried or there's a concern that that could lead to there being mismatches. For example, a fish moving into an area after a migration, but that main prey resource it would have depended on not being there because its phenology has shifted.

[11:16] Obviously, this is an exaggerated case, but it is where we think that there could be important ecosystem consequences that would have further impacts on our fisheries, and other activities.

[11:30] We can imagine that there's going to be a complicated response to this the further up the food web you get, but I guess more complicated because not every organism is the same.

[11:39] Here at the top of this figure, which is a rather messy figure, or busy figure, and I could spend some time on it, we have a series of seasons that drive changes, and physical processes of those systems, and that those then impact those lowest trophic levels.

[11:59] The most important thing I want to get out of this is that there are a multitude of responses by these upper larger organisms, upper trophic levels, in response to these physical changes.

[12:12] In particular, if we use this last example, which is the anadromous fish life strategy or seasonal strategy where we have immigration from the ocean into fresh water systems, the reproduction and growth of those young, and an eventual immigration, is being impacted not only by the ocean processes but also by land based and precipitation river outflow events.

[12:36] Those are also going to be important for any species living in the coastal ecosystems because river outflow will influence circulation patterns within that complicated circulation in these coastal oceans.

[12:52] Now, I'm going to shift to a case study, and then I'm going to hand it off to Michelle for her to talk about the nesting sea birds as an example. She'll finish up the talk with a discussion about some of the implications of this work as it relates to our management and adaptation of coastal management.

[13:13] It's best to start with a very simple question. Our question is have there been changes in the timing of a spring alewife spawning migration? As a follow up, what might be driving any of those changes that we're seeing? I think it's important to introduce this fish species in a little bit more detail because its phenology is marked by these shifts in its habitat use.

[13:39] Actually currently, right now in our neck of the woods, we're seeing river herring moving into fresh water systems. They reproduce and leave these adhesive eggs that are semi-adhesive eggs that then incubate, and hatch into these weird spaghetti-looking fish with little yolk sacks on them.

[13:54] Those then grow up eventually into these silverine juveniles which, over the course of the summer and fall, will migrate out into the ocean where they'll join an at-sea population, which, at about three to five years of age, will start making these spawning migrations.

[14:09] Once they've done this spawning migration, they can repeat that every year until they're either eaten or captured in a fishery.

[14:21] That means that there are series of phenological moments or phenophases, as the National Phenology Network would call them.

[14:29] We're investigating aspects of spawning and hatching using otoliths of fish that we catch during the summer, to back-calculate the ages of those fish and understand the patterns of their spawning and hatching.

[14:40] We're studying migration with other partners and researchers at the University of Massachusetts, trying to link it to conditions within the fresh water.

[14:51] If I started trying to talk about all of that, that would be the whole hour, so I'm just going to focus, for today, on this migration component and our key question. There is other data sources, but we're very fortunate that every year these fish make this migration, and they make themselves available for counting individuals.

[15:09] Here, the picture is essentially a fish-counting device. It's a electronic counter which has a beam of light that as the fish passes, it breaks that beam of light and that counts an individual fish. This, as well as video counters and assistance science can accumulate these counts and create this data.

[15:30] Which will be the size of the run that is occurring on a specific date throughout the year, showing, as you would expect, peaks and valleys associated with certain climatic variables. Which we're not going to talk about today, but we're also investigating what is driving these day-to-day changes in the numbers of fish.

[15:48] Here's a great picture of an area where assistance science counting would be an ideal location where you got this little pale background where fish is being moved through the system can be counted. Here are some example of some fish.

[16:02] That's great. Let's really bring you into the middle of this run for a moment to show you what actually looks like when you're under water. Here's a river herring in the beginning of a spawning migration. You'll see it's a rather chaotic-looking event and a wonder to see. If you ever get a chance, I highly recommend to go and do so, obviously with social distancing in effect.

[16:23] You'll also notice that there are some small little eels. These are young eels that have made their migration from the Sargasso Sea as young and are now moving up into these systems.

[16:33] A lot of questions about what drives these river herring runs and the consequences of those runs, which is something we spend a lot of time studying.

[16:41] We're very fortunate to have received data from the Massachusetts Division of Marine Fisheries from 1990 to 2017, in 12 locations, with annual and daily counts of those runs. I'm not going to show you all the data from all the areas. Actually, I guess I will in a moment, but we'll just start breaking it down.

[17:00] We take each run and we create these phenology metrics -- the initiation, median, and end of the run, which correspond with the 5th, 50th, and 95th percentile of that run in terms of numbers. What we see when we look at these phenology metrics and how are they're changing is that there's not a consistent change across the systems.

[17:24] In fact, there's very few examples where we see, in a specific system, a significant change in that run. If there is a response, it seems varied based on the system. This is rather interesting to ecologists but a little bit more frustrating from a management perspective.

[17:43] There is a lot of inter-annual variation though. That inter-annual variation, as it turns out, is being driven by climate variables. The most key variable, in particular when it comes to initiation, is the sea surface temperature in the winter.

[17:57] We see a significant impact when we do a modeling of the entire dataset of this cold winter temperatures, sea surface temperatures. Here you can see that effect on the run-initiation date with a scaled winter sea surface temperature in this model.

[18:15] We have some impact of winter severity driving the timing of the beginning of the run. There's always a lag effect. The fish are responding to something that has happened in the past, not to the exact current conditions.

[18:29] Of course, there's a little bit of a nuanced view that I won't talk too much about today, but it obviously gets more complicated than that.

[18:36] There's also an effect of latitude on run size. I'll come back to run size in a moment.

[18:42] The rest of those metrics -- the median and end date -- show a decreasing impact from that winter sea surface temperature. You start seeing that spring transition date starting to have an impact, as well as that annual Gulf Stream index in the median phenology index. What we can see is that there's always a lag, and the lag is closely related often to the season ahead of it.

[19:09] The end is a complicated affair, and I don't want to spend too much time on it, other than to say that it seems that a lot of things are affecting the end of the run, and it's probably being driven by a lot of factors that are really embedded in the precipitation, available water, and drought conditions that could prevail in certain years. That's a part of a broader conversation.

[19:31] I mention this because I think it's really important to think about. We are undergoing active restoration of many of these populations, because the species as a whole, or both species, alewife and blueback, are at relatively low abundances. Those restoration activities are driving increases in run size, you would hope.

[19:52] Those are also imparting some changes in what we're seeing in terms of phenology metrics. This is marginally non-significant change, but a change nonetheless, in the initiation date. As you can see, the end date is staying much more stable.

[20:07] What we're seeing is that there is an impact globally on all of the populations of run size increasing or decreasing the day of the year, so an earlier initiation and a relatively steady end, and therefore also driving an increase in the duration of the run.

[20:25] We think that these have important management implications that Michelle will discuss towards the end.

[20:33] We're very fortunate to have received some Woods Hole Sea Grant funding to extend our work from looking just in freshwater and the marine, to freshwater migration of the adults, asking questions about what happens in freshwater in the river and the estuary to those young that are produced by those spawning runs.

[20:51] We're going to be taking samples from multiple locations and asking questions about what is happening to the demographics in each of those areas, and how there may be bottlenecks, in particular in the timing and movement, or are there particularly good times to be moving out of these systems in freshwater and moving into the estuaries?

[21:13] Eventually, those individuals will join the at-sea population. You can see that we have in multiple places here a life history population model. I'm very fortunate to work with our Division of Marine Fisheries in Massachusetts on a number of projects, and they continue to today.

[21:29] This is one of the outputs of that. This project was led by Gary Nelson, and Benjamin Gahagan, Mike Armstrong, myself, and Alison Bowden, asking questions about what are causing the population changes. In order to do that, we created not a particularly simple model. I would say that Gary's not a fan of simple models.

[21:48] It was a really interesting way of thinking about and testing whether there are impacts of certain conditions. I'm just bringing this up to point out that river temperature influencing migration, lake temperature influencing spawning, as well as you could pick out a number of other places in this where there's an influence that has an important phenological aspect to it.

[22:10] The bigger problem is that we know very little about these impacts and mechanisms. One of the things you learn when you do this kind of activity is all the things you don't know. Here, we found that we do not understand the environmental and physiological influences that affect adult immigration and young-of-year or juvenile emigration.

[22:31] We have real issues of understanding what is going on in estuaries, the length of time that these individuals are resident in estuaries. We're hoping that we can really understand all of this in the next few years as we gain more data.

[22:44] I'd be remiss to mention that we're really interested in these interactions among species. Here, we have an alewife that has managed to have a lamprey find it somewhere in the ocean. These interactions really are the sum of these individual time and space interactions, whether it's in their predator-prey dynamic or otherwise.

[23:06] Those accumulate to form these complex ecosystems, which are really the source of what we're most interested in.

[23:14] I'll point out a couple of things here. These river herring are part of this little Alosinae box. Understanding how they are influencing the food web is important, but also understanding how the rest of the species are moving and how their phenologies are changing the interactions with other organisms.

[23:31] Those could be some commercially important species, like winter flounder, which we're going to starting to work on soon. It could be the fisheries themselves, and so engaging stakeholders directly and asking them what they're seeing and how they're responding and how they plan to respond to these changes in time is a really important aspect of this.

[23:49] Last, there are really important species of concern, such as seabirds, which are also going to be impacted by these changes. With that, I'm going to hand it over to Michelle. Thank you.

Dr. Michelle Staudinger: [24:05] In the second half of this talk, I'm going to be focusing on nesting seabirds in the Gulf of Maine and trying to answer the question to whether or not they're becoming temporarily mismatched with their key prey.

[24:21] I wanted to mention that this work has been conducted in collaboration with the US Fish and Wildlife Service, the Maine Coastal Islands National Wildlife Refuge, and National Audubon's Project Puffin and the Seabird Restoration Program, as well as a variety of state partners.

[24:37] A lot of this work, the results of a master's thesis of a student, Keenan Yacola, that Adrian and I co-advised. He's also an island manager with Project Puffin spent a great deal of time out on islands with these birds.

[24:53] A variety of seabirds migrates the islands along the coast of Maine to breed and raise their young during the summer season. Some of these species, such as the Arctic tern, migrate as far as the Southern Ocean. This earned them the award for making one of the longest migrations of any animal on earth.

[25:10] We know that highly migratory animals are at higher risk for mismatches and resources, [inaudible] the long distance between their overwintering grounds and their seasonal summer foraging and breeding grounds.

[25:22] The highly productive waters of the Gulf of Maine has historically served these species quite well, providing high-quality prey to refuel them after their long journeys and provision their young during the nesting season. However, there's a lot of concern that shifting availability of some of their preferred prey may be limiting these populations.

[25:44] Adrian already mentioned, but I think it's worth mentioning again, that we know that the Gulf of Maine is a hot spot of warming, with rates of change three times the global average.

[25:54] The fastest rates of warming have been observed in the system during the summer season, which is of particular importance to seabirds, which is when they're coming to nest and raise their young.

[26:06] We also know that a large variety of marine fishes and invertebrates that would serve as prey to seabirds and other higher trophic levels are showing adaptive capacity to climate change by shifting their ranges, both longitudinally, typically moving north, as well as to deeper waters in search of thermal optimum.

[26:27] We have well-known shifty prey, but not so shifty predators. A recent meta-analysis of 145 seabird species, it was found that seabirds are not adjusting their breeding time in response to changes in sea surface temperature.

[26:44] This disconnection between these different levels of the trophic level potentially could lead to problems for the survival of seabirds in the Gulf of Maine system. This was motivation for this case study.

[27:01] The analysis that I'm going to be talking about today that we've been working on for the last few years are focused on a [inaudible] tern species. Terns have some particular constraints on their foraging ecology.

[27:12] First, that terns are somewhat small-bodied for seabirds, and they plunge-dive at the surface, and they're only able to access prey within the very top few centimeters of the water column. They also typically only carry a single prey item at a time. They largely forage on young-of-year juvenile fishes.

[27:33] Second, they have a limited radius around their nesting islands in which they can access food. The further they have to fly to find foods, the fewer trips they can make to provision their chicks, and the more energy they have to expend to raise their chicks.

[27:49] Of high concern is that cold-water associated fish species are moving out of the Gulf of Maine and warm-water associated fishes are moving in. One species of particular concern to seabird managers is the fish prey species shown here, which is the butterfish. This is a deep-bodied fish prey, and it takes quite a bit of energy and time for a chick to manipulate it and swallow it.

[28:16] [inaudible] is also considered a lower-quality prey species to some of the more historically important fish prey that terns and other seabirds have relied on, which are typically higher in lipids and fat reserves to help their chicks grow.

[28:33] The last comprehensive study of tern foraging ecology in Gulf of Maine was conducted about 20 years ago, and a lot has changed since with rising climate temperatures. In working with our state and federal and nonprofit partners, we set out to quantify long term trends in seabird foraging ecology in this region.

[28:53] The National Audubon Seabird Restoration Program and US Fish and Wildlife Service has collected chick diet data since 1986, which we're really lucky to be able to have access to this 30-plus-year data series. It covers four species of terns, common, arctic, the federally-endangered roseate, and least tern, and covers seven islands in the Gulf of Maine, shown right here.

[29:18] We set out to evaluate tern diets across these four different species across the seven islands, and the 30-plus-years of data, and also evaluate the underlying drivers of their occurrence in the diets.

[29:33] Just to give you an idea of the amount of effort that goes into collecting these data, in this video, you can see in the background, there's a bird line and there's an observer monitoring these two chicks.

[29:48] Interns and volunteers spend their entire summer out on these islands, and hours and hours each day, and over the weeks, and over the months during the season, recording these prey observations.

[29:59] What you're observing here, this parent is delivering [inaudible] to one of its two chicks. The chicks are also marked so that they can be tracked for their growth and survival throughout the summer nesting season.

[30:17] In this slide, I'm showing the original overview of the four different tern chick's diets. You can see the different species on the bottom left-hand corner, and the frequency of occurrence of the major prey groups on each of these species' diets.

[30:35] The take-home here is that over the 30-year time period, over 70 percent of the fish prey in the four tern-chick diets contained only three prey groups.

[30:47] In hake group, this is related to mostly the white hake, but it also contains several other species, unknown proportions of offshore hake, silver hake, and fourbeard rockling. There are two species of sand lance, an inshore and an offshore species, that occur in the diets.

[31:04] The herring complex is primarily Atlantic herring, but also includes two river herring species that Adrian talked about earlier, alewife and blueback herring. Then there's a variety of all sorts of different kinds of fish in other fish categories.

[31:21] The two main takeaways here are that the narrow diets on such a few species of prey makes these species more vulnerable to climate impact and other stressors. There's also high potential for competition between species that co-mixed together on shared islands.

[31:43] If we look at the diets using a diet diversity index, which is shown on the Y-axis on the plot, we see that Arctic and common terns have higher dietary diversity overall in comparison to least terns and roseate terns.

[31:57] The higher dietary diversity largely comes from the fact that arctic and common terns are consuming marine and terrestrial invertebrates, whereas least terns and roseate terns are fish specialists. We know that across the range in the Northeast, roseate terns are not only fish specialists but also sand lance specialists.

[32:18] In a recent paper that I led that just came out in the last month, we looked across a variety of studies and found that roseate tern diets consistently contained high amounts of sand lance, falling in at around 30 to 100 percent of their total diet.

[32:35] In some places, roseates, their diets are a hundred percent just one or two species of fish, which is pretty incredible. There are exceptions. We did find exceptions on one of the islands in our study system, Eastern Egg Rock.

[32:50] In this pie chart you can see that sand lance actually don't make up a large percentage of the overall diet of roseate terns over the time periods that we evaluated. Hake is more important in their diets at this location.

[33:05] We also found some evidence for adaptive capacity in this location, where in 1992 on this island, we found that roseate terns took advantage of unusually high amounts of another Gadus species, pollock, at nearing 30 percent of their diets to their chicks. There is some evidence that they may be able to take advantage of [inaudible 33.25] .

[33:25] For the next series of slides that I'm going to show, the results will only be focused on common terns. This was our most robust data series, covering the most number of years and all of the islands.

[33:45] Here, the main thing that I want to show is some examples of how the trends in the diets vary across location. On the X-axis we have years and on the Y-axis we have frequency of occurrence. What you'll notice is we don't see the same trends across the different locations.

[34:01] For example, on Stratton Island, we see that sand lance, which is shown on this brown line, that in the late 1980s, 1990s, and early 2000s, sand lance was quite important to common tern diets. Then, we see a large decline in the early 2000s before it increases again. Concurrent with the decline in the diet of sand lance, we see an increase in herring and hake in their diets.

[34:31] Now, when we look at Eastern Egg Rock and Jenny Island, we see that sand lance were provisioned to the chicks in much lower amounts. We may even see a little bump in the frequency of occurrence during the same time periods where we saw a decline at Stratton Island.

[34:44] The take-home here is that we don't see a unilateral response across the different locations. There's quite a bit of variation, in fact. This indicates that the different colonies are subject to different localized conditions and that decreases or increases in prey have been affecting the colonies and populations equally across the Gulf of Maine.

[35:09] When we look at within-season dietary phenology, so, in these plots here we still have frequency of occurrence on the Y-axis, but now we have day of year on the X-axis. The earliest day of year, 170, corresponds to approximately June 15th, which is when egg-laying is occurring.

[35:28] Year day 192, the midpoint of the chick-bearing season, is around July 10th, where the chicks begin to hatch. Then the end of the season, year day 215, late July-early August, we see that's when chicks are starting to fledge.

[35:46] The take-home here is that we see different patterns of occurrence over the course of their chick rearing season. For example, our cold-water associated hake species are more important earlier in the chick rearing period right after egg laying and up to hatching, whereas herring become more important later in chick-rearing period more towards fledging.

[36:10] Sand lance are more or less consistent over the chick-rearing period, maybe showing a slight decline towards fledging. Interestingly, we see a slight increase in the probability of frequency of occurrence for our warm-water associated butterfish, as well as the catch-all category for other fish.

[36:32] In this next analysis, we looked at how changes in temperature affected occurrence in tern diets. We saw on the X-axis this time we have increasing in sea surface temperature and probability of frequency of occurrence in the diets.

[36:46] This is capturing the probability of the kinds of the different prey over time, given rising temperatures. Each one of these lines in each one of these plots represents a different island in this case. What we can see is that with increasing sea surface temperature, we see a decreasing probability of the frequency of occurrence of our cold-water associated hake. That's what we would have expected.

[37:09] What we don't see is the increase in warm-water associated butterfish with increasing sea surface temperatures across the different islands, with the exception of one location, Matinicus Rock. This would be a colony that we would want to watch closely to see what the local foraging conditions look like during future extreme warm years and how that population responds to those temperature increases.

[37:38] Another important result here is with increasing sea surface temperature, we see an increase in the probability of frequency of occurrence of a diversity of these other fish species. What we think is happening here is that as our cold-water associated hake species are declining, the birds are needing to supplement their diet with whatever is most available in their local environments.

[38:02] The last result that I wanted to show from this case study is the relationship between that earlier spring transition date or earlier onset of spring that Adrian was talking about earlier, and the probability of our cold-water species.

[38:17] Here, we see when spring arrives earlier, we see a lower probability of this cold-water associated species. This is where we really see the greatest likelihood for potential temporal mismatch in this prey resource, given the shifting environmental seasonal conditions.

[38:36] The work that I've just walked you through is really just the first step in a longer term goal to link prey conditions to population dynamics of these seabirds. Our next steps are going to be to link the diets to chick growth and survival metrics and really try to dig in deeper on understanding what conditions make for a good or a bad year for these birds.

[38:59] Now, I'd like to wrap up with some implications and management strategies for how we deal with all of these shifts in phenology and changes to the way that species are interacting.

[39:12] First of all, where, when, and how much species are shifting. There's a lot of impacts on socioecological and economic systems on the Gulf of Maine. It can impact the species population dynamics that we care about. I think it has potential implications for interactions with human activities, which I'll go into in a moment.

[39:32] It also affects the efficacy of our management tools. Many of our management tools are fixed in time and space and do not well-account for species shifting in response to climate change.

[39:44] Some examples of this are time of year restrictions. For example, water withdrawals and other activities within the coastal stream systems where diadromous fishes are migrating. Fishery seasons and closed areas are typically fixed in time, and the construction and operation windows of emerging industries.

[40:06] We'll also be looking at historical trends. These may not match with what's currently happening, given recent warming and climate change. We can't change species interaction, we can't change the timing in which species are occurring or moving, so how do we manage for shifting phenology?

[40:29] I'm going to propose a few strategies, some of which are familiar to many [inaudible] working on this system already. The first is to manage across landscape scales for diversity. By giving species a wide range of habitat and food options, we increase their resilience to a wider range of conditions.

[40:52] This portfolio approach to maintaining diversity of conditions for a species really thinks far more holistically about what's happening process, for example, the Gulf of Maine as a whole rather than individual points, but those individual points are really important to understanding how these localized systems are responding to local conditions.

[41:15] An [inaudible] example [inaudible] stream flow and the stream temperature is for seabirds of this local foraging conditions.

[41:22] As Adrian talked about earlier, by restoring populations and reducing [inaudible] stressors the increase in resilience of that population overall [inaudible] , we saw when we increased the population size with around five [inaudible] are migrating through these systems.

[41:45] That just gives these species more options in terms of their total [inaudible] .

[41:53] Another thing to bring in here in terms of reducing non-chronic stressors is to increase connectivity between key habitats for these fishes. In the case of the diadromous fishes, we've done a really great job of blocking their access to historical habitat through dams and other barriers.

[42:10] This [inaudible] slide show the available habitat for diadromous fish back in the 1600s and how much it fell by the 1900s, [inaudible] and other barriers.

[42:27] Another way that we can help increase resilience at the system level is through holistic assessment of diversity vulnerability. This recent report, the state of the ecosystem [inaudible] in the last month or so.

[42:40] This is typically given to fishery management councils, reporting on the state of the fisheries. In this past version of the reports, it made an effort to include information on different species, including seabirds and other animals, and thinking about how they've been affected by changes in fisheries.

[43:01] This was a big step forward, thinking about the system more holistically, and what they want to do in the future.

[43:09] Along those lines, there's been a large movement toward ecosystem-based approaches to fisheries management, taking precautionary approaches that account for uncertainty, considering those species interactions, predator-prey relationships is important. We're thinking about protections for forage fish [inaudible] .

[43:28] We know from our work that there's a direct relationship between seeing a herring in the diets of the seabirds and herring recruitment. In recent years, there's been a number of steps that have been taken to protect forage fish and thinking about [inaudible] predators.

[43:49] Some of the recent control rules has some instructions on catch in coastal areas that include seabird nesting habitats. Hopefully, we'll need to [inaudible] during this critical period.

[44:11] Lastly, as Adrian mentioned about earlier, there's a balance to be struck between looking at the historical long-term trends and real-time monitoring. In Cape Cod Bay, which is a critical foraging ground for North Atlantic right whales, there are seasonal closures and state limits [inaudible] .

[44:34] We know from recent years that these closures are being pushed later and later into the year. Our work with our collaborators at the Anderson Cabot Center in Green Lake and at the New England Aquarium has shown that the habitat use of Cape Cod Bay [inaudible] three weeks over the last 20 years.

[44:56] Looking at these long-term trends in habitat, it's really important, but if you look at this plot, you can also see that there's a lot of variation, and so we still need the real-time monitoring to then know when the whales have left the area and if restrictions can be lifted. There's bound to be strong [inaudible] .

[45:16] Just to wrap up, our works has shown that [inaudible] very wisely cross our coastal marine species and cultivation in the Gulf of Maine. A lot of our results are challenging previous assumptions about what we know about ecological shifts. For example, in terrestrial systems, the default is that timing is shifting earlier and that's not necessarily true in systems.

[45:44] A high variability across populations creates uncertainty for a management which is very difficult, but it actually may create resilience across ecological ecosystem scales.

[45:54] If every population within a region is responding the same way, then they've all been exposed to the same amount of risk. This variability should be monitored carefully and scaled up so that we can better understand what's happened at both a local level and how ecosystems fail.

[46:12] These ecosystem perspectives are really important to understand how different components of the system are responding relative to each other. Some of the ecosystem modeling results that Adrian was showing earlier, we see all these issues are connected.

[46:27] You can sometimes have unintended or surprising results in how changes in one species will affect another. We do need to think about the question here which is to buffer against the uncertainties and [inaudible] .

[46:42] Finally, it's really important that we engage [inaudible] and understand their perceptions and their responses with changes in species that they rely on, so that we understand how they're going to respond to the system changes, so that we all buy into the management strategies that we might be able to account for the shift and timing of these issues that we care about.

[47:09] With that, I'd like to thank all of the people that have contributed to this work. We have a really wonderful collaborative group spanning multiple institutions. [inaudible] has been wonderful to work with.

[47:24] If you'd like to learn more about any of this work, there's a number of products available on Climate Adaptation Science Center website on their projects page. With that, we'll go to some of your questions.

Amanda: [47:38] Awesome. Thank you so much for sharing your very interesting findings with us, Adrian and Michelle. It looks like we have some time left over for questions and we have a few that have come up during the presentation. Our first question is for Adrian, and that was, "What is the temperature value you used for the spring transition dates?"

Adrian: [48:00] Well, that's a great question. That's asking me a very tough question to actually know what was used as the specific value. I will say that in the figures that were showing the shift in the spring transition dates, the temperatures used are associated with those locations, so they're the average, long-term mean of the specific location for which we're talking.

[48:26] Those figures had a number of different locations, including the Gulf of Maine, so it's for that body of water, within that body. It's different for each of those regions, obviously, because the average temperatures are different. If you're really interested, you can send me an email and I'll dig up the actual values and get them to you, but that's all I have as an answer right now.

Amanda: [48:48] I'd also mention that Kevin Friedland at the Northeast Fisheries Science Center calculates these values for multiple regions on a quarterly basis. They can be accessed on the Northeast Fisheries Science Center Web page, or if you just Google search for spring transition dates, it should come up.

Adrian: [49:08] Sorry about that. I should have realized I had an opportunity to give Kevin some props.

Amanda: [49:11] [laughs] We did get, also, another question for Adrian. There was a comment that I understood regarding that runs are not consistent for herring and that it is great for an ecological perspective, but frustrating from the management perspective in terms of over-management.

[49:31] Please provide some examples of how management of nature has led to detrimental effects. Why don't we just let nature happen? Maybe, with climate change we have to help, but recognize human activity has greatly influenced the effects of climate change from monitoring the activity of terns. You had mentioned that chicks are marked. How is that done [inaudible 49.53] .

Adrian: [49:52] That was two questions. I'm going to let Michelle take the monitoring chicks question. This question on the perspective here of management, me, personally, I view management as really only being able to be effective on people. The management that I'm talking about are actions we would undertake in these systems.

[50:22] For example, with river herring runs we have dredging windows and water withdrawals that are impacting a couple of different life stages during the migration. Basically, you're trying to avoid impacting them during the spawning season.

[50:36] That works well if you know when that time is, what that time window is, but it obviously starts falling apart when that's shifting over time. The challenge from a management perspective is not managing the river herring themselves, it's managing the activities that we engage in within these cold-water sheds and in the areas that they're active during their residence in the region.

[51:00] That's the challenge, and how to deal with that as the climate changes and we experience differing rainfall and climate variables, as well as onto the drought, and so forth, which really complicate being able to make appropriate time and place restrictions work for that species. I hope that answered the question.

Amanda: [51:20] We have another question in the Q&A box. Why did puffin phenology get later when spring phenology got earlier?

Michelle: [51:29] That's a great question, and that was one of the studies, I believe, in the Gulf of Maine synthesis. I do not believe that that paper looked at the underlying drivers, but I would have to go back and look.

[51:44] That's really the key question, is that we don't know why species are shifting later in every case, or earlier. Looking at those underlying environmental drivers and linking them to those life events is really the crux of all of this work.

[52:00] I did want to answer the other question that came in about marking the chicks. At least for terns, I can say that handling the chicks doesn't affect whether the parents will return to them. In fact, the parents are quite attentive when the chicks are being marked and handled for growth studies.

[52:24] They love to dive bomb your head. We have to wear hard hats when we're out there or deterrents on the top of our heads to keep them from basically trying to attack us the entire time we're handling the chicks.

[52:35] Part of these provisioning plots where the chicks are being monitored, they're actually just fenced off with very low fencing, but the birds can actually hop over and of course, the adults can just fly over and access their chicks. The chicks are just marked with a colored marker and so that just stains their feathers.

[52:56] Then we take [inaudible] like wing chord length and weight around the rearing season, to track their growth and measure them every several days, but it doesn't affect the parents coming back to them.

Adrian: [53:10] I'm just going to follow up really quickly on something that Michelle mentioned about the puffins. I don't want to be quoted on this exactly, but my recollection of that study is to do with the fact that as the prey shifts, and you get less ideal prey, that the time it takes them to brood the chicks and have them fledged goes later.

[53:31] This was one of those places where there's an unusual effect that is mediated through a predator-prey relationship. If I'm wrong, someone can send me an email.

[53:40] [laughter]

Adrian: [53:40] I do believe that that was the reasoning for that. Although it was a long time ago that we did that work, so I'd have to go back.

Amanda: [53:47] OK, another question. Your holistic assessments of risk and vulnerability seem to focus on ecosystem. However, to get buy-in from hostile quarters, have you given thought to potentially spanning this holistic assessment to incorporate other sectors, perhaps infrastructure or economy?

Michelle: [54:04] I wasn't involved in the state of the ecosystem report. I think the primary audience for that report is the fishery management councils. They do take into account social and economic, as well as ecological changes in the system. They take into account oceanographic and climate changes in influencing the dynamics of the commercially managed fish stocks.

[54:35] I'm not familiar with their engagement process for different sectors, but I know that they try to capture the effects at least on different sectors. I'd have to defer more to our colleagues that know the answer that question further.

Adrian: [54:53] I'll just jump in and add a couple of things. The state of the system report does contain socioeconomic indicators, although they're rather at large scales.

[55:03] I'll just add to say that we recognize this as a really, really important part of our research in the future, and that we think that engagement of stakeholders is a critical part of developing functional and actual working adaptive strategies.

[55:20] We have a project out of the [inaudible] station that is focusing on engaging stakeholders within Massachusetts specifically, although obviously, there's a broader conversation here, and trying to understand where some of these issues are and how to address them. This is a long term goal and something that is just going to be a slow march.

[55:38] There's a lot of different activities that can be impacted by these shifts, whether it's fishing or whether it's offshore wind. These are very contentious, potentially, and need just a lot of listening and engagement.

Amanda: [55:53] Yes. Why no apparent response of warm-water fish to increasing temperatures?

Michelle: [55:58] I just wanted to clarify that the occurrence data that I was showing was the frequency of occurrence in the tern diets. That's not the same as the frequency of occurrence in the environment.

[56:16] That would be pretty critical information to compare to see if there is any behavioral aspects of the way that the terns are foraging. Are there any preference that they might be exerting in what prey they're selecting from the environments, which is resulting in those trends.

[56:38] We still would need that information. There's some great data out there that is collected, for example, by the National Marine Fisheries Service, in terms of larval distribution and adult distribution in the environment.

[56:53] A lot of the state agencies also collect data in more inshore areas that would overlap with the seabird foraging areas. The main challenge is the level of spatial and daily resolution that we would need for those data to be collected at, to truly make a comparison of what's in the tern diets versus what's in the environment.

[57:21] Based on the data that's available, we can get some more general spatial and temporal trends. We haven't yet looked at butterfish in the environment from those scientific survey data. What we were showing today was just what's reflected in the diets. That would be a great next step to answer that question.

Adrian: [57:43] I will just add very briefly that we did see the increase in the other fish. I suspect that if you break that down, you'll see that there are more warmer water species involved in that. This area, the Gulf of Maine, is somewhat more resilient to the advancement of these warm-water fish because it gets pretty cold in the winter time.

[58:03] I think that this is a bit of also just the reality that herring are going to remain an important part of the diets and [inaudible] are going to remain an important part of those diets.

Michelle: [58:15] That reminded me that we have seen an increase in haddock and pollock. I mentioned pollock, but haddock also, it's another data-ed species that seems to be benefiting from the warmer temperatures in the Gulf of Maine. We have seen their populations increase in recent years.

[58:33] These could be two potential species that we're seeing in the diets I may not have detailed so much in the slides, but that we know are benefiting from warming temperatures and that the birds are finding. That is something to look into further as well.

Amanda: [58:50] On behalf of the US Fish and Wildlife Services and the US Geological Survey's National Climate Adaptation Science Center, I wanted to say thank you very much to Adrian and Michelle for taking time out of your day to share your very interesting cases with us and being with us here today.

[59:06] Thank you, again, to everyone for attending today's webinar. See you again soon.