Port Mahon Delaware

Sea level rise is causing erosion that has all but swallowed this once-thriving town on the shore of the Delaware Bay.

These pictures taken in March 2011 tell the story of the current state of Port Mahon, Delaware. Once a popular bayside community, now all that is left is a boat launch lamp accessible at low tide. At high tide the road is impassible.

Physical deterioration was evident in March at the beginning of the spring storm season. It appears that if the road is not heavily maintained, it may be completely washed away with a few months. (See the photos with broken asphalt).

These sobering photos were taken on March 23, 2011, on a calm overcast day with light rain. Since this was not a full moon or any other lunar cycle, I concluded that this was a normal high tide. We generally expect tide levels to increase over the spring.

Two watermen had pulled boats and were leaving Port Mahon Road as I entered. It was about an hour before high tide. I wondered if they knew that the road became impassable at high tide, but I drove ahead anyway. The deepest water was about six inches, which is about the maximum my little SUV can handle.

On the long drive back home, I reconsidered the possibilities of hardening to resist erosion (the strategy used by my local community in New Jersey) as compared to a strategic retreat (the strategy endorsed by the scientific community). My guess is that we’ll do everything possible to avoid addressing the issue in a responsible and effective manner.

Delaware sea level response report

Note added at republishing: This post covers an older report. Since the date of publication water level rise forecasts have been revised upwards.

Delaware’s comprehensive sea level rise risk assessment report confirms that long term strategic retreat from low-lying coastal areas is the most likely response to water level rises expected to continue for coming decades.

Key findings of the report are:

– a water level rise of 1.6 to 4.9 ft. is considered likely by 2100

– Up to 10% of the state will be permanently flooded

– Up to 75% of specifically named towns will be permanently flooded

– Public safety will be at risk; fire and emergency stations, police stations, and evacuation routes will be flooded

– Public health may be at risk by the thousands of septic tanks, wastewater pumping stations and treatment facilities that will be flooded.

– Revenue from tourism is at risk and local governments will face increased funding needs for maintenance or repair of shore points.

 

Download the Assessment
Full Document (5 MB)
Executive Summary
Introductory Sections (5 MB)
Natural Resources
Society & Economy
Public Safety & Infrastructure
Mapping Appendix (37 MB)
Introduction
Maps – Natural Resources (8.5 MB)
Maps – Society & Economy (6MB)
Maps – Public Safety & Infrastructure (13 MB)

Blue claw crab research

Yesterday I interviewed Dr. Paul Jivoff, a professor at Rider University, by telephone to learn more about topics at the intersection of science and business of blue claw crabs. Dr. Jivoff is a local expert in blue claw crabs and we’ve communicated several times over the past few years, including our meeting with the Rider Development Office last year about the possibility of a research site at Money Island.

The big picture goal is to ensure that our business plans are aligned with the available science and, to the extent possible, consider the possibility of future biological impacts on the industry.

This is an annotated abstract from one of Dr. Jivoff’s papers that overviews the life cycle of blue claw crabs:

“Blue crabs are considered estuarine residents with all life history stages, except for the larval stages, occurring in estuarine waters. Adult females release larvae into the water column near the mouths of estuaries (Millikin and Williams, 1980). Larvae are carried offshore where at least 30 days are required to go through seven zoeal stages (Millikin and Williams, 1980; Epifanio, 2007). As a result, blue crab larvae represent one trophic link between estuarine and oceanic food webs. The final plank-tonic stage (megalopa) returns to the estuary, via wind-driven currents and tides (Epifanio, 2007), where they metamorphose to form the first juvenile stage (<5 mm carapace width) and become benthic. These juveniles grow rapidly, molting on average every 3–4 weeks depending on water temperature (Smith and Chang, 2007), making them important prey for a variety of fish and birds, but they are also important predators on other small invertebrates (Lipcius et al., 2007). Therefore, young juveniles (<20 mm carapace width) occupy shallow, structured habitats that also contain food sources including seagrass beds, macroalgae, and oyster reefs (Lipcius et al., 2007). During the 12–18 months required to reach sexual maturity (at 90–100 mm carapace width), habitat use expands based on size and density-dependent factors (Hines, 2007; Lipcius et al., 2007). Smaller juveniles (20–30 mm carapace width) move to alternative nursery habitats including marsh creeks and marsh-fringed mud flats (Lipcius et al., 2007). Larger juveniles (>20 mm carapace width) begin venturing into unstructured habitats and, as they grow, inhabit deeper areas where they continue to be important predators but are prey to fewer organisms (Hines, 2007). Unlike females that exhibit a final molt to reach maturity, adult males grow throughout their lives (reaching sizes of >200 mm carapace width), molting every 30–40 days depending on temperature, and they typically return to more protective habitats during molting, as they are particularly vulnerable to predators. As a result of ontogenetic shifts in habitat as well as movement into lower salinity areas, blue crabs can be found in a wide array of habitats, throughout the estuarine-to-ocean salinity gradient (e.g., 5–35 ppt) (Hines, 2007; Lipcius et al., 2007). Because they represent both predator (contrary to popular belief, they are not scavengers) and prey in these habitats, blue crabs are a critical component of the estuarine food web both within and between estuarine habitats. Blue crabs have been an important food item for humans since the early 1700s and have supported a commercial and recreational fishery since the 1800s (Kennedy et al., 2007). As a result, blue crabs are part of the historic, economic, and social fabric of communities along the Atlantic and Gulf coasts of the United States. Blue crabs are consumed as “hard crabs” (crabs with a hard carapace, typically in the intermolt stage) and as “soft crabs” (crabs with a soft carapace as a result of recent molting) (Kennedy et al., 2007). The predominant fishing techniques vary with the season and with the sex of the harvested crabs. During the warmer seasons (late spring-late fall), blue crabs are typically harvested with a trap or “pot,” and the catch is predominantly males. During the winter, particularly in the mid-Atlantic region, blue crabs are harvested by a dredge, and the catch is predominantly females.” (Jivoff, P.R.. (2016). Blue crabs. Encyclopedia of Earth Sciences Series. 109-110. 10.1007/978-94-017-8801-4_4.)

We discussed industry practices that might support a larger crab population; specifically that we will not support winter dredging of crabs. Also, we opened discussion on the possibility that Money Island might be a good location for future crab research.

The language of climate change at the bayshore

My work involves speaking with a wide range of people about observations in nature. I am clear that this is the largest issue affecting our lives, our community’s future and our society but this ‘heavy stuff’ is of course not the message of day-to-day communications. More likely, I get questions like “Why are the fish coming in later?” or “Why can’t I get a building permit?” These are not simple topics to discuss. Like many others in a similar position, I struggle to find the right words to use to communicate the extent of what I observe on a day-to-day basis here at the bayshore. I’ve had more formal training is science in general, and climate science in particular, than most people. Some call it indoctrination. I call it command of facts. But that’s not necessarily an advantage when it comes to leadership. A leader must engage a wide community group base but how is this possible on the issue of climate?

When I think about local media coverage like last June’s front page article in the Philadelphia Inquirer where I was one of several intelligent, educated and well-informed business owners (I know them all pretty well since this is such a small community) who deal with climate issues on a day-to-day basis at the core of their businesses. The writer chose to give more print and apparently did not make any attempt to fact check the statements of the local mayor who said “There is no sea-level rise, and it’s a bunch of hogwash”. The mayor admits that he has no training in science or climate issues. Yet his statement as given more prominence that the considerable better-informed sources. Why would a major newspaper allow this? Would they have printed the story the same if the mayor said the earth is flat or that the planet was created 5,000 years ago? If not, then what possible basis are we using to justify the public expression of these unchallenged false climate statements? This is just one example. I am also aware of a local book writer whose work in progress seems to give credence to climate deniers.

I know that certain words trigger an angry response, can cause our businesses to lose customers and may even cause us to lose government infrastructure funding. I’ve been physically assaulted and verbally threatened for my talk about climate-related issues. Yet I’ve been clear that climate denial is not a logically or legally defensible position. In fact I would be willing to be a witness for the prosecution in future cases that challenge climate change deniers.

In our local market dominated by trumpist thinking, even mention of the term “climate change” in print sets off angry responses. Other words like “strategic retreat”, “inundation”, “sea level rise”, “fact”, and even “science” itself are controversial.

So how then do I talk about the things I see and the things I can’t explain without an understanding of climate issues? It his latest book Thomas Friedman1 offers some suggestions from his conversations with Greenlanders:

“Just a few years ago,… but then something changed…”

“Wow, I’ve never seen that before…”

“Well, usually, but now I don’t know anymore…”

“We haven’t seen something like that since…”

That’s all climate-speak—“surpassing,” “highest,” “record,” “broken,” “biggest,” “longest.”

The fact is that the impact of climate change, acidification, sea level rise and warming temperatures affect me and my industry more than anything else. It would be nice to be able to talk about it.


1Friedman, Thomas L.. Thank You for Being Late: An Optimist’s Guide to Thriving in the Age of Accelerations (p. 162). Farrar, Straus and Giroux.