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Posts Tagged ‘Shorebirds’

Early days on Delaware Bay – Horseshoe Crabs Just Beginning To Breed as Shorebirds Arrive

Saturday, May 19th, 2018

by Larry Niles

Horseshoe Crabs Just Beginning To Breed as Shorebirds Arrive

 

Delaware Bay horseshoe crab eggs reach sufficient levels to give red knots and other shorebirds a good start on the fat they need to fuel the last leg of their yearly journey in the first week of the stopover ( May 12-19).  Knots need at least 180 grams to fly to the Arctic and breed successfully.  This week we caught birds that weighed 93 grams which is 30 grams below fat-free weight.  These birds had just arrived from a long flight, probably from Tierra del Fuego, Chile or Maranhão, Brazil.  In the same catch, we weighed red knots as high as 176 grams or only 5 grams from the 180-gram threshold.  These birds are probably from Florida or the Caribbean wintering areas and so arrive earlier,  resulting in them having more time to gain weight.  All together it looks like a normal early migration and a modest horseshoe crab spawn, just barely enough for the birds in the bay.

shorebirds in a net

Our team prepares a catch of knots turnstones and semipalmated sandpipers for extraction to keeping cages. The birds will be covered to prevent feather abrasion before extraction (Photo by Stephanie Feigin)

However, we are still short of about half the population.  Our bay wide count won’t take place until next week on May 22 and 26. At this point it looks like we have about 14,000 knots in the bay, of which 8,000 are in New Jersey. In the last 5 years we have had a bay wide population of about 24,000 red knots.  The situation is similar for ruddy turnstones and sanderlings.  The southernly winds of the next few days will almost certainly bring in the rest of the flock by mid-week.

The Stopover Habitat is Growing

 

The condition of the stopover is mixed.

The work of Niles & Smith Conservation Services, Conserve Wildlife Foundation of NJ, and American Littoral Society continues to supply high-quality habitat for horseshoe crabs. We have developed an efficient system for maintaining the essential requirements of a good spawning beach, deep and large grain sand with berm heights that prevent over washing in a way that keeps cost down. First, by creating low oyster reefs to break waves in lower tides, thus protecting beaches from wind waves at low and mid tides.  Second, by placing sand on beaches that typically erode fast losing sands to adjacent creek inlets and the next beach south.  This way we can use one restoration to restore three different places.  For example, Cooks Beach loses sand to South Reeds.

 

restored beach in Delaware Bay

Thompsons beach before and after restoration by American Littoral Society and partners. (Photo by Larry Niles)

Oddly these successes may be contributing to the next big problem for the birds. The state of Delaware has been carrying out much larger scale beach replenishment projects that have added significant new sandy beach for crabs spawning.  At the same time the Atlantic States Marine Fish Commission has failed to deliver on its promise to increase the number of crabs.  The population is still 1/3 below carrying capacity or the number that existed 20 years ago.  The same number of crab divided by more beach equals decreasing crab densities.  Decreasing densities means fewer eggs reaching the surface because crabs are not digging up existing eggs to lay their own.

In other words, we need more crabs.

The Industry Finds New Ways around the ARM Quota

 

But the resource agencies seem perfectly happy to keep killing adult crabs for both bait and bleeding at near historically high numbers. Bait harvests recorded as coming from the bay have stayed the same, however other states such as NY are still taking and landing large numbers of crabs despite having no known crab historic population of their own. Additionally, Virginia states that a crab population still exists in the state, even though most field biologists consider them lost.  The truth is they are very likely taking Delaware Bay crabs and landing them as their own.

The Conservation groups are no longer satisfied with this loose regulation and are calling for regulations similar to those used for Striped Bass.  The Delaware Bay harvest should be restricted to just the quota agreed upon by everyone through the Adaptive Resource Management system.  All other landed crabs should be genetically linked to a source population, and if they do in fact come from Delaware Bay they should be taken out of the ARM quota. No one should be allowed to get away with killing our crabs outside the quota.

Or just stop the senseless killing of these valuable animals as bait for the dying couch fishery.

 

crab eggs graph on Delaware Bay

This graph compares the finding of Botton et al 1994 from horsesoe crab egg surveys done in 1990 and recent counts done in 2017

 

The same goes for the killing of crabs by the companies bleeding crabs.  The industry makes untold millions (the numbers are hidden from the public) but does virtually nothing to conserve the crabs while killing thousands. Their own estimate is well over 65,000 a year, but independent estimates double that.  This killing could also stop because a new synthetic lysate is available and can be used now, potentially cutting the need for natural lysate by 90%.

An Ecosystem Collapse and the Need for More Crabs

 

Why kill such a valuable animal?  It all started because the fishing industries saw little value and figured why not destroy the population until they are no longer economically viable.  Its called economic extinction and sadly it’s a tradition amongst Delaware Bay fishers still carried out this to this day on eels, conch, and other species.  But they didn’t know back in the early 90’s they would wrecking the entire ecosystem.

In 1991, we counted an average of 80,000 horseshoe crabs/meter squared.  Now we count 8,000.  Then the eggs stayed at that level for all of May and June then hatched young at similar densities. In other words, the horseshoe crab was a keystone producer of an abundant resource that maintained the bay ecosystem.  It was not just chance that at the same time the bay has one of the most productive weakfish and blue claw crab fisheries in the Atlantic coast.  Fish populations blossomed with the flush of horseshoe crab eggs and hatched young each year.

Now we must bring it back.  For the birds, for the fish, and for the people who love to bird and fish.

 

storm delaware bay horseshoe crabs

A storm looms over Delaware Bay. The last 4 days have been rain, some intense and cold. The water temperature needs to be 59 degrees or so for Crabs to spawn. On Saturday the 19th the water temperature fell below and the spawn virtually stopped in many places. It should resume with the warmer temperatures of Saturday and Sunday.

We are grateful to the National Fish and Wildlife Foundation and other donors who make this project possible.

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

Tierra del Fuego: The View from Above

Saturday, March 24th, 2018

Just above and to the right of the plane shadow, thousands of shorebirds gather. Photo by Joe Smith

CWF scientists recently returned from a trip to Tierra del Fuego where they studied red knots and other migratory shorebirds that spend the month of May at New Jersey’s Delaware Bayshore.

CWF consultant Joe Smith captured some incredible aerial images of the coastline holding a flock of thousands of shorebirds in his blog story. See more photos of the flock and read Joe’s introductory overview about the trip here. Stay tuned for more installments about this vital trip.

Red knot numbers down in wintering grounds

Monday, February 26th, 2018

The Press of Atlantic City covered the troubling findings of Conserve Wildlife Foundation’s recent expedition to Tierra del Fuego in Chile to survey wintering red knots.

The numbers of red knots – an endangered migratory shorebird that spends every May along New Jersey’s Delaware Bay coast feasting on horseshoe crab eggs – declined by more than 20 percent between the team’s counts last year and this year.

Click here for the full story.

CWF Scientists Follow At-Risk Migratory Shorebirds to Tierra del Fuego

Wednesday, February 7th, 2018

by Stephanie Feigin, Wildlife Ecologist

 

Over the past two years, our team, with the help of funding from the Neotropical Migratory Bird Conservation Act, has worked to create critical habitat maps and detailed threat maps for at-risk shorebird species in Northern Brazil and in Tierra Del Fuego, Chile. These projects have established the foundation for conservation planning in these important wintering areas for migratory shorebirds like red knots.

 

Brazil:

Two years ago, our team began working in Northern, Brazil covering the Atlantic coastline of both Pará and Maranhão state between Belém and São Luís. Our team conducted two successful excursions to Brazil taking point count surveys of wading shorebirds collecting approximately 44,700 individual bird sightings to add to the database our team created for the critical habitat maps (Figures 1 & 2).

Figure 2. Results from the 2017 point count survey

                    Figure 1. Results from the 2016 point count survey

 

David Santos and Larry Niles conduct point sampling surveys in Maranhão Brazil.

We conducted surveys using point count methods using fixed radius plots positioned along transects, with all wading birds counted within the 250m radius. Transects were conducted by either walking or while in a boat across various tidal stages and a variety of habitat types including mangrove creeks, sand flats, mudflats and beaches.

 

 

 

Brazil Team: Carla Meneguin,
Paulo Siqueira, Ana Paula Sousa, Larry Niles, Juliana Almeida, Carmem Fedrizzi Joe Smith, Stephanie Feigin, Yann Rochepault, Laura Reis and Christophe Buiden (photo by Juliana Almeida)

 

 

 

Our team then created threat maps of the region from coastal development, mining operations, offshore drilling, and shrimp farming to help inform future conservation planning and mitigate impacts of these activities to the critical shorebird habitat in the region.

 

Chile:

This year, with a second round of funding, our team conducted work in Tierra Del Fuego, Chile to create critical habitat and detailed threat maps for Bahia Lomas in Chile. Bahia Lomas is both a globally significant RAMSAR wetlands site and a Western Hemisphere shorebird site of hemispheric importance.  

 

Shorebirds in Bahia Lomas

Historically, Bahía Lomas and nearby Rio Grande supported wintering populations of 67,000 red knots –  the largest wintering area for knots in the Western Hemisphere. In the last 30 years, however, the population has declined to less than 15,000 knots in Bahía Lomas and the population in Rio Grande is functionally extinct (Morrison et al 1989).

 

 

Aerial Survey over Bahia Lomas

 

 

 

This January our team conducted surveys along the coast of Bahia Lomas to understand distribution of shorebird species within the region, using the same sampling methods, study key roosting and feeding habitats, and delineate critical habitat and threats to the region to inform future conservation and minimize impacts to shorebird populations.

 

Team in Chile including Ross Wood, Stu Mackenzie, Carmen Espoz, Larry Niles, Joe Smith, Yann Rochepault, Christophe Buidin, Antonio Larrea, Richard Lathrop, Stephanie Feigin and Amanda Dey.

Over two weeks our team of New Jerseyans and Canadians conducted point-count sampling surveys throughout the bay with large assistance from our partners from Universidad Santo Tomás in Chile to determine key habitats. Additionally, our team conducted four aerial surveys to get species distribution counts on a large scale of the whole bay at various tide stages, as well as a helicopter survey to continue the population counts of the region done by Dr. Guy Morrison. Finally, our partners with the Universidad Santo Tomás conducted marine invertebrate sampling surveys. These data will be combined to aid in the creation of a GIS mapping system that can identify the most important shorebird habitats in the region.

 

 

 

 

 

In the next few months our team will use these data and overlay them with threat mapping to determine the critical habitats undergoing the greatest threats.  This project is designed set the stage for proactive conservation planning that will mitigate future threats and will hopefully uncover the source of ongoing declines to the shorebirds in this region.

Citation:

 

Morrison R.I.G. & Ross R.K. (1989) Atlas of Nearctic shorebirds on the coast of South America. Canadian Wildlife Service Ottawa (Canada).

 

2017: Piping Plover Nesting Season

Thursday, November 16th, 2017
How did they do?

Emily Heiser, CWFNJ Wildlife Biologist

Statewide pair-nest success was down this year, but remains above the long-term average. photo by Northside Jim.

For the 12th year in a row, the Conserve Wildlife Foundation of New Jersey, in partnership with New Jersey Division of Fish & Wildlife’s Endangered and Nongame Species, assisted in monitoring and managing the state’s Beach Nesting Bird Project.  Four species are regularly monitored throughout the field season: piping plovers (federally threatened, state endangered), least terns (state endangered), black skimmers (state endangered), and American oystercatchers (state species of special concern). Statewide, piping plovers are of particular concern as their numbers continue to decline and federal recovery goals have not been achieved.  (more…)

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