Jump to content

West Dennis beach closed indefinitely after two piping plovers were killed

Rate this topic


foxfai

Recommended Posts

1 hour ago, FizzyFish said:

don't forget about the millions used/killed for the production of  LAL.  Limulus amebocyte lysate  for endotoxin testing.

You can correct me if I'm wrong, but I'm fairly sure the vast majority of those get returned to the sea.

The Sultan of Sluggo

Link to comment
Share on other sites

1 hour ago, bob_G said:

You can correct me if I'm wrong, but I'm fairly sure the vast majority of those get returned to the sea.

They're returned, but like bass, release mortality occurs.  No one knows what percentage of released horseshoe crabs die, but there is speculation that it may be fairly high.

"I have always believed that outdoor writers who come out against fish and wildlife conservation are in the wrong business. To me, it makes as much sense golf writers coming out against grass.."  --  Ted Williams

Link to comment
Share on other sites

13 hours ago, BrianBM said:

I lack the PhD but have read that the decline of various shorebirds is largely attributed to a shortage of horseshoe crab eggs.

There have been multiple causes, that affect birds at various points in their lives.

 

The decline in horseshoe crab eggs is a problem, as they fuel the northward migration.

 

Beach development is part of the problem, as the increased human activity caused by condos, hotels, and even actively used beaches and parks disturbs the nesting and interferes with the chicks.  People also bring garbage, which in turn attracts things like raccoons and gulls, which then predate on the nests.  People also lead to more feral cats, which add to the problems.  People and predators can also interact to make things worse.  For example, a plover chick may interpret a kite as a predatory bird, and in trying to escape the kite's attention, make itself more available to another predator, such as a gull.

 

Then there are vehicles.  The plover's primary defense is camoflage, with respect to the nests, the chicks, and the adults.  When a plover of any age feels threatened, its typical reaction is to freeze in place and hope it can't be seen.  Often it won't be seen by a driver, and can be run over.  We usually first think of anglers' vehicles in that context, but they are only a part of the problem.  Non-angling-related driving, including the official vehicles that empty beach trash and clean the beach, are also a problem when it comes to concealed chicks.

 

And beach cleaning itself is an issue, as the chicks often feed on insects found in the strand line.  Removing the dead and decaying weed, as is often done, denies the chicks a food source, and chicks that are in the strand line when cleaning takes place are very likely to be killed.

 

The bottom line is that we're dealing with an animal that evolved to survive in a very fragile habitat.  It did well so long as that habitat was largely undisturbed.  But the changes brought by the movement of people to the shore has done substantial harm.  The current rebuilding plan seems to be working; from what I've read, one of the rebuilding criteria, 2,000 breeding pairs on the East Coast, has now (barely) been met.  But the big hump we'll have to get over is productivity--an average of 1.5 chicks per nest fledging--because it is the chicks that are most vulnerable to human-caused death.

"I have always believed that outdoor writers who come out against fish and wildlife conservation are in the wrong business. To me, it makes as much sense golf writers coming out against grass.."  --  Ted Williams

Link to comment
Share on other sites

 

From USGS:   https://www.usgs.gov/publications/long-term-effect-bleeding-limulus-amebocyte-lysate-annual-survival-and-recapture

 

In the U.S., 525,000 horseshoe crabs (Limulus polyphemus) per year have been captured during 2013–2017, brought to biomedical facilities, and bled to produce Limulus amebocyte lysate (LAL), then mostly released to the area of capture. The Atlantic States Marine Fisheries Commission estimates short-term bleeding-induced mortality to be 15% (4% to 30%), resulting in mortality of approximately 78,750 horseshoe crabs annually in recent years comprising a minor portion (<13%) of the up to one million annual coastwide landings dominated by harvest for bait. However, the long-term effect of bleeding for LAL on annual survival and spawning behavior is unknown; thus, results from short-term studies alone might underestimate bleeding effects at the population level. To address this knowledge gap, we analyzed data from the U.S. Fish and Wildlife horseshoe crab tagging database to estimate the differences in survival and recapture rates of bled and not bled horseshoe crabs tagged in the same years and geographic area. Contrary to expectation, survival was not lower for bled crabs compared to unbled crabs. Differences varied, but survival estimates tended to be higher for bled crabs than for unbled crabs. However, biomedical culling and selection for younger or healthier animals could have resulted in biomedically tagged individuals representing a healthier subset of the overall population with subsequent higher survival. Furthermore, the tagging analysis revealed a post-bleeding reduction in capture probability, which could indicate decreased spawning activity, evident in males more than females. Continued tagging of bled and unbled crabs in the same geographic area while recording age class and sex will contribute to the further resolution of LAL production’s effect on horseshoe crab populations.

 

 

" I did my worst, but I did it well "

 

 

Link to comment
Share on other sites

48 mins ago, CWitek said:

There have been multiple causes, that affect birds at various points in their lives.

 

The decline in horseshoe crab eggs is a problem, as they fuel the northward migration.

 

Beach development is part of the problem, as the increased human activity caused by condos, hotels, and even actively used beaches and parks disturbs the nesting and interferes with the chicks.  People also bring garbage, which in turn attracts things like raccoons and gulls, which then predate on the nests.  People also lead to more feral cats, which add to the problems.  People and predators can also interact to make things worse.  For example, a plover chick may interpret a kite as a predatory bird, and in trying to escape the kite's attention, make itself more available to another predator, such as a gull.

 

Then there are vehicles.  The plover's primary defense is camoflage, with respect to the nests, the chicks, and the adults.  When a plover of any age feels threatened, its typical reaction is to freeze in place and hope it can't be seen.  Often it won't be seen by a driver, and can be run over.  We usually first think of anglers' vehicles in that context, but they are only a part of the problem.  Non-angling-related driving, including the official vehicles that empty beach trash and clean the beach, are also a problem when it comes to concealed chicks.

 

And beach cleaning itself is an issue, as the chicks often feed on insects found in the strand line.  Removing the dead and decaying weed, as is often done, denies the chicks a food source, and chicks that are in the strand line when cleaning takes place are very likely to be killed.

 

The bottom line is that we're dealing with an animal that evolved to survive in a very fragile habitat.  It did well so long as that habitat was largely undisturbed.  But the changes brought by the movement of people to the shore has done substantial harm.  The current rebuilding plan seems to be working; from what I've read, one of the rebuilding criteria, 2,000 breeding pairs on the East Coast, has now (barely) been met.  But the big hump we'll have to get over is productivity--an average of 1.5 chicks per nest fledging--because it is the chicks that are most vulnerable to human-caused death.

Great read, and well said.:clap:

The Sultan of Sluggo

Link to comment
Share on other sites

16 hours ago, R.R. Bridge Fisher said:

Yup

Why can't they build some nesting boxes?

 

They could easily just mark the nests with painted wooden posts. Then nobody would run them over. 

Edited by Fish Monkey

(*member formerly known as ''duntonsdragons)

Link to comment
Share on other sites

3 hours ago, Fish Monkey said:

They could easily just mark the nests with painted wooden posts. Then nobody would run them over. 

It's the little chicks running around that get squished. They like the sand roads but they're so small they get trapped in tire ruts. They also seem to get squished in parking lots alot too.

They're so tiny, most people never see. Especially going 20 in the 5 zone.

Link to comment
Share on other sites

12 hours ago, Fish Monkey said:

They could easily just mark the nests with painted wooden posts. Then nobody would run them over. 

They put a cage around the nest when it’s just eggs and the beach can stay open. It’s after the chicks hatch and before they can fly that’s the problem. Why we can’t have a spotter watch the chicks and escort vehicles past at least a few nests is a mystery. It would at least keep a part of the beach open. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to register here in order to participate.

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×
×
  • Create New...