Conserve Wildlife Blog

Posts Tagged ‘migration’

New Jersey’s Hidden Coast — After the Storm

Thursday, June 23rd, 2016
New Jersey’s Hidden Coast — Episode 3

by Lindsay McNamara, Communications Manager

At 8:00 PM on October 29th, 2012, Hurricane Sandy made landfall in Brigantine, New Jersey, only about 30 miles from New Jersey’s Hidden Coast – the Delaware Bayshore. The storm was devastating for the people of the area, many of whom lost their homes and livelihoods. It was equally hard on the area’s wildlife, bringing many species, including the famous horseshoe crab and red knot, perilously close to extinction.

 

What happened? Watch the story unfold in the third episode of our video series.

 

A new episode of our video series “New Jersey’s Hidden Coast” will air every two weeks throughout the summer! Catch a glimpse of the bay, the horseshoe crab at the center of the bay’s system, and the incredible relationship between horseshoe crabs and migratory birds, like the red knot. We will reveal the real value of horseshoe crabs, the challenges to the ecosystem, and the potential for a thriving regional economy along the Bayshore. We will show Hurricane Sandy as a catalyst for decisive action and the work being done to rebuild the area for both people and wildlife.

 

Over the next several weeks, we will explore the use of “living shorelines” instead of bulkheads and the central importance of marshes to the marine ecosystem. We will discover the on-the-ground, grassroots efforts of the community to build oyster reefs alongside veterans. And we will examine the future of the Bay and the work that needs to be done to preserve our conservation successes thus far.

 

Discover Delaware Bay:

 

Lindsay McNamara is the Communications Manager for Conserve Wildlife Foundation of New Jersey.

 

The Real Value of Horseshoe Crabs

Wednesday, June 8th, 2016
New Jersey’s Hidden Coast – Episode 2

by Lindsay McNamara, Communications Manager


Horseshoe crabs may be one of the most unusual animals in the world, but they’re also one of the most extraordinary. They’ve been around for hundreds of millions of years, and we’re only now starting to understand just how important they are – not just to the natural world, but also to the world of medicine. Discover the real value of horseshoe crabs, found throughout New Jersey’s Hidden Coast – the Delaware Bayshore.

 

A new episode of our video series “New Jersey’s Hidden Coast” will air every two weeks throughout the summer! Catch a glimpse of the bay, the horseshoe crab at the center of the bay’s system, and the incredible relationship between horseshoe crabs and migratory birds, like the red knot. We will reveal the real value of horseshoe crabs, the challenges to the ecosystem, and the potential for a thriving regional economy along the Bayshore. We will show Hurricane Sandy as a catalyst for decisive action and the work being done to rebuild the area for both people and wildlife.

 

Over the next several weeks, we will explore the use of “living shorelines” instead of bulkheads and the central importance of marshes to the marine ecosystem. We will discover the on-the-ground, grassroots efforts of the community to build oyster reefs alongside veterans. And we will examine the future of the Bay and the work that needs to be done to preserve our conservation successes thus far.

 

Discover Delaware Bay:

 

Lindsay McNamara is the Communications Manager for Conserve Wildlife Foundation of New Jersey.

New Jersey’s Hidden Coast

Tuesday, May 24th, 2016
Discover New Jersey’s Hidden Coast – the Delaware Bayshore

by Lindsay McNamara, Communications Manager


Making your plans for Memorial Day Weekend at the Jersey Shore? Discover New Jersey’s “other” coastline, a Hidden Coast, the Delaware Bayshore.

 

A new episode of our video series “New Jersey’s Hidden Coast” will air every two weeks throughout the summer! Catch a glimpse of the bay, the horseshoe crab at the center of the bay’s system, and the incredible relationship between horseshoe crabs and migratory birds, like the red knot. We will reveal the real value of horseshoe crabs, the challenges to the ecosystem, and the potential for a thriving regional economy along the Bayshore. We will show Hurricane Sandy as a catalyst for decisive action and the work being done to rebuild the area for both people and wildlife.

 

Over the next several weeks, we will explore the use of “living shorelines” instead of bulkheads and the central importance of marshes to the marine ecosystem. We will discover the on-the-ground, grassroots efforts of the community to build oyster reefs alongside veterans. And we will examine the future of the Bay and the work that needs to be done to preserve our conservation successes thus far.

 

Discover Delaware Bay:

 

Lindsay McNamara is the Communications Manager for Conserve Wildlife Foundation of New Jersey.

Creek Mouth Shoals Provide Key Habitat During a Cold May

Monday, May 23rd, 2016
One of a Series of Updates on the 20th Year of the Delaware Bay Shorebird Project

by Dr. Larry Niles, LJ Niles Associates LLC

In spite of the very spotty horseshoe crab spawn, the shorebirds on Delaware Bay seem to be gaining weight on schedule. Below you will find a graph composed of the average weights of all the red knots by our team for the last 20 years. The curve is the result of combining all the data we collected and shows the sweet spot for most knots. As they arrive, they take time to gain weight but after about 5 days they start gaining weight rapidly. After the 26th or so, birds start reaching the critical weights necessary to safely reach the Arctic breeding grounds. One can see the curve deep at the end of the month because fat birds fly off leaving the less fat behind. In general, weights above the line are good, below the line not good. The large squares on the graph are the average weight of this year. So far, so good.

Average Red knot weights from catches made in 1997 to 2016. The most recent are the big squares. So far average weights are following normal pattern of weight gain.

Average Red knot weights from catches made in 1997 to 2016. The most recent are the big squares. So far average weights are following normal pattern of weight gain.

Cannon net firing over red knots on Delaware Bay

Cannon net firing over red knots on Delaware Bay

This is a bit of a surprise for the team. The weather here on Delaware Bay is wet and cold. The water temperature struggles to lift above 59 degrees, the temperature necessary for a crab to spawn on Delaware Bay. So far, the temperature has been below 59 degrees more than above. We had good spawns in the last few days, but only in key places.

Water temperature at the mouth of Delaware Bay.

Water temperature at the mouth of Delaware Bay.

A key place for horseshoe crab spawn happens to be the mouths of small creeks. The New Jersey side of Delaware Bay is blessed with many small intertidal creeks, most draining only marsh or small inland watersheds. Some of these creeks have names, Goshen Creek, West Creek, Nantuxent Creek, but many do not. Almost all have shoals at their mouth with the bay because bay currents, tidal flow and wind driven waves act against each other to settle sand coming from adjacent beaches or from inside the creek drainage. Much of the sand lost from our restored beaches settles into these shoals. For horseshoe crabs, these shoals are sweet places.

A sandy shoal at the mouth of the nameless creek between Reeds and Cooks Beach. At the time of this picture, over 3,000 knots and 1,000 ruddy turnstones were using the shoal and the inner sandy beach behind the shoal. Photo by Stephanie Feigin.

A sandy shoal at the mouth of the nameless creek between Reeds and Cooks Beach. At the time of this picture, over 3,000 knots and 1,000 ruddy turnstones were using the shoal and the inner sandy beach behind the shoal. Photo by Stephanie Feigin.

Red Knots in flight on Cooks Shoal. Photo by Stephanie Feigin.

Red Knots in flight on Cooks Shoal. Photo by Stephanie Feigin.

Red Knots on Cooks Shoal. Photo by Stephanie Feigin.

Red Knots on Cooks Shoal. Photo by Stephanie Feigin.

Red Knots on Cooks Shoal. Photo by Stephanie Feigin.

Red Knots on Cooks Shoal. Photo by Stephanie Feigin.

Usually, the shoals lie just under the high tide line and are composed of large grain sand, the optimal conditions for a good crab spawn. However, the most important characteristic and key to this unusually cold May, is the warming water flowing out from the marsh drainages. On a flooding tide, colder warmer flows into the vast marshes of the Delaware Bay. This warms the water. On an ebbing tide, it flows out the creek and over the shoals, making them slightly warmer and more conducive to inducing crabs to spawn. Even on these cold days, they literally climb over themselves to breed on the shoals. The shoals also protect the inner mouths of the creeks thus making the sandy shores at the mouth of the creek a crab spawning heaven.

Breeding horseshoe crabs. Photo by Jan van der Kam.

Breeding horseshoe crabs. Photo by Jan van der Kam.

However, as it seems usual with this blog, there is a growing concern. Right now, most of the red knot population on the bay is feeding on these shoals along with thousands of other species, but only half have arrived from southern wintering areas. We now have about 12,000 red knots on the bay and in a day or two we should find another 12,000 falling from the sky. Will there be enough eggs? Will the water temperature finally reach normal levels? These are the important question for the next few days.

 

Learn More:

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

Cold Water Stops Horseshoe Crab Spawning along Delaware Bay

Saturday, May 21st, 2016
One of a Series of Updates on the 20th Year of the Delaware Bay Shorebird Project

By: Dr. Larry Niles, LJ Niles Associates LLC

Shorebirds and no horseshoe crabs along the Bay.

Shorebirds and no horseshoe crabs along the Bay.

It’s well known that the Delaware Bay shorebird stopover depends on horseshoe crabs, but few know that Delaware Bay is a near perfect horseshoe crab habitat.

 

There are many places on the eastern seaboard where horseshoe crabs breed. Most are too small to provide sustenance for energy-starved shorebirds. Places like Cape Romain Refuge in South Carolina have enough horseshoe crabs so that one breeding female unearths eggs of another and thus lays out a tidy meal for shorebirds. But the areas are small and at this time unimportant to the population of shorebirds. Most of the others are too small to have eggs reach the surface. Its only in Delaware Bay where crab numbers reach into the millions and spawn in such great numbers that they spread like a carpet over nearly all beaches from Gandy’s Beach to Villas, approximately 20 miles of spawning habitat. The number of eggs and ultimately hatched young reach staggering numbers.

Horseshoe crabs breeding at night.

Horseshoe crabs breeding at night.

The huge population of horseshoe crabs on the bay is no accident. The bay almost seems built to suit the crabs. Crabs need beaches with large and deep sand flats, allowing just enough water to sufficiently oxygenate the eggs without drowning them.  They need the sea floor to gently rise into breeding beaches, allowing easy access. While breeding, crabs have to eat small bivalves, which they find in abundance in the bay’s extensive intertidal and subtidal flats.

Horseshoe crab eggs.

Horseshoe crab eggs.

The most important aspect of the bay is its quickly warming waters in the spring. On Delaware Bay, horseshoe crabs don’t breed until waters reach 59 degrees. You won’t see this temperature on the Atlantic Coast until June. Not so on Delaware Bay!  Although the bay has deeper water, mostly in sloughs that snake under the surface out to its mouth at Cape May, most of the water is relatively shallow  usually less than 18 feet. That may sound deep, but keep in mind the Chesapeake has 100 feet water for most of its length and deeper water throughout. The shallow water of Delaware Bay allows it to heat up soon after the air temperature rises.

 

Unfortunately, it also cools down quickly and because of this the crab spawn has stopped. The bay’s water temperature went up dramatically in late March and April, so much so that we worried it might reach the critical 59 degree threshold in April long before the birds arrived in May. But then the warm weather stopped and the bay temperature dipped than rose, several times in fact. By early May, it had gotten just above the threshold, heating up to about 61 degrees at the Cape Henlopen marine buoy. We hoped for the best. Crabs started to breed in good numbers on a few beaches, like Reeds Beach, but were thin elsewhere. We had about 20,000 shorebird relying on the spawn and the eggs that were brought to the surface.

chart-13

Than the bay cooled down again. A nasty western wind and cold front enveloped our area over the weekend and the cool weather followed. By Monday, the temperature went down again and the crab spawn stopped. This is bad.

 

When the spawn stopped the birds hovered up the remaining eggs in a few days. Then they started wandering to find eggs in odd places, under houses, along bulkheads. Some even went to areas like the oyster aquaculture racks to find eggs to the delight of the people trying to expand aquaculture. But what they saw was desperation.

Herring gull hunting red knot, Cooks Beach, New Jersey. Photo by Jack Mace.

Herring gull hunting red knot, Cooks Beach, New Jersey. Photo by Jack Mace.

Worse the Black Back and Herring Gull that feed on eggs and overturned crabs couldn’t find eggs and started eating shorebirds. By the end of Thursday (May 19) we found 8 dead red knots. These gulls can swallow small sanderling and semipalmated sandpipers like gum drops, so we really don’t know how many shorebirds died.

Herring gull hunting red knot, Cooks Beach, New Jersey. Photo by Jack Mace.

Herring gull hunting red knot, Cooks Beach, New Jersey. Photo by Jack Mace.

Relief might be in sight though. Thursday, Friday and today will be warmer. The bay’s temperature is back up over 60 degrees. Thursday night we had a fairly good spawn. Hopefully we will be back in business soon.

 

Learn More:

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.