Crabology 101: All about crabs and bait

[7deadlyplugs]

A little about the molting of blue crabs
http://www.serc.si.edu/education/res...b/molting.aspx

[hookedonbass]

Can anyone ID this crab shell I found near an inlet? thanks

[hookedonbass]

Dark Skies I have to tell you I thoroughly enjoy the threads you create. I can tell a lot of painstaking research goes into them. Whether it is information about the moratorium and declining bass numbers or guidelines and suggestions about fishing, you really try to pass along your knowledge. At one time I had the energy you had but now I am enjoying my golden years. Thank you for trying especially to educate the younger anglers out there. Bucket head I used to rake crabs a long time ago. They are without a doubt the best offering you can use to entice bass for the hot summer weather. It is tedious and time consuming and I can assure you that Bucket head earns every bass he catches. Too much work for me at this stage but I enjoy your stories. Good luck gentlemen.

I agree with clamchucker. Some of the most informative threads on the net on this site. Thanks guys for sharing all this great knowledge.

[Monty]

This is a great thread.
Wonder in there will be any effects on the crab population from sandy.

[Monty]

Molting and full moon article:
http://www.bluecrab.info/fullmoon.htm


Are there more soft crabs during a full moon?

This is a question that is asked quite frequently and yet no one seems to have a definitive answer. There appears to be a general consensus among watermen and some scientists that a full moon (and, to a lesser extent, a new moon) does indeed play a role in a crab's molting cycle, but this is based purely on anecdotal evidence.

"While I do not have hard data to support the contention that there is increased shedding on or around a full moon, from personal observations of the commercial soft crab production industry, there is an increase in peelers and soft crabs several days before and after a full moon" says Mike Oesterling of the Virginia Institute of Marine Science.

There are several possible explanations for this phenomenon. One explanation might be that during a full (and new moon) the tides are unusually high or low (called "spring" tides). This is because twice a month the moon and sun are in line with the Earth and therefore, their combined gravitational pull is greater. During a spring tide, more shoreline grasses are submerged (or exposed) which would provide a larger area of cover and protection for crabs to molt. Or, perhaps it's because crabs are able to exploit expanding feeding grounds or have more time for feeding in the shallows. Mr. Oesterling notes that "in the summer months, food availability has a major effect on shedding activity. If a crab does not satisfy the physiological need to shed (increased muscle tissue, body cavity 'cramping', etc.), it will not enter the molting cycle." In other words, if it doesn't get enough to eat then it's not going to outgrow its shell.

Jennifer Martin of the University of Connecticut's Department of Ecology and Evolution says "In the lab I had two thousand crabs that I was rearing and a full moon definitely meant most of them were molting. Why? I am not sure." This would seem to indicate that the increased gravitational pull during a full moon somehow directly influences the crab since food availability and cover would not be factors in a controlled laboratory environment.

From a skeptical point of view there is a more realistic explanation. The lunar cycle (month) is fixed at 29.53 days. This means that the oceans and other water bodies which are affected by the earth-moon system experience a new tidal cycle roughly every 30 days. The Atlantic blue crab molts about 18 to 23 times, not including larval molts, during its life. The instar, or period between molts, grows progressively longer as the crab gets older, ranging from 10-15 days for one-inchers to 30-50 days for legal size "keepers" and beyond.

Because the lunar cycle occurs at a fixed 29.53 day interval and because the molting cycle is variable (as low as every 10 days to as high as every 50 days), any correlation between the two is purely coincidental. Perhaps it's because the 30-day lunar cycle roughly correlates to the 30-day molting interval of legal-size keepers that people tend take special notice. For example:

Small, immature crabs have a short 10-20 day molting cycle which does not correlate to the lunar cycle. Since these crabs are of no commercial interest their molting behavior is not closely monitored.

Legal-size hard crabs have an approximate 30 day molting cycle. This very closely matches that of the lunar cycle. Because of their high commercial value, crabs of this size are placed in holding tanks and are monitored very closely until they molt. Special notice is taken when, totally by coincidence, crabs are seen molting during a full moon. This is called subjective validation or selective memory. Subjective validation is a psychological phenomenon in which people tend to remember significant or coincidental events and forget the others.

Large hard crabs (those with a molting cycle in the 40-50 day range) are scarce and therefore are not monitored as closely.

So, are peelers are more prevalent during a full moon? Probably not. While it's difficult to argue against the fact that some commercial harvesters claim to see a correlation, we should take this with a grain of salt. We know that a crab's molting cycle is variable and the lunar cycle is fixed. It is also a fact of human nature that we try to attach special meanings and significance to things that occur in regular cycles, especially when they seem to coincide with celestial events (full moons, astrology, etc.). It's fun to say that crabs molt only during a full moon. It has an eerie, supernatural feel to it and makes for great crab lore.

Does the "peeler run" start during the first full moon in May?

Along the same subject line, most people claim that the first full moon in May signifies the start of the season's peeler run (some believe that the first run will occur when the first dogwood blossoms begin to open.) The peeler run is simply the time that crabs awaken from their winter dormancy and head to shallow waters to molt. Especially prevalent are mate-seeking females which did not reach their terminal molt the previous year.

Mike Oesterling states that the first sheddings are more water temperature controlled than by lunar phase. Once water temperatures are above about 59 °F (15 °C) crabs of all sizes begin to molt. Crabs begin shedding in April, generally in the shallower creeks and marshes, where sunny days can significantly elevate the shallow water temperature. These are also generally smaller-sized animals. The "first run" that people talk about is really the "doubler run" of mating females. There have been some years when this "run" did correspond to the May full moon, but over the past 8 to 10 years the "first run" in the lower York River and Mobjack Bay has occurred around May 15-19, regardless of moon phase. Additionally, this "run" occurs at different times in different sections of the Bay, again suggesting a water temperature impact.

[jigfreak]

Awesome find monty very cool.

[baitstealer]

I was fishing a few weeks ago and on the beach at night were these little crabs about 2" long. They were whitish and moved with lightning speed. I thought about using them for bait but there was no way I could catch them. Tried for about 5 minutes and gave up. Someone in a tackle shop told me they are called ghost crabs. Does anyone know more about them and have you ever seen them out there at night? Or was I imagining things, lol?

[chas527]

took a walk along the beach in portmonmouth.i counted 105 dead horseshoe crabs, in just a mile.does any body know why they are dying.

[basshunter]

^^^Possible too much algae or too little oxygen. MHO.
nice report steve. finchaser happy to hear about bigger blues there have been a lot of aggressive snappers eating my gulp for the last few weeks its time for a change.

[paco33]

Chas something I found on horseshoe crabs. Dont know if it applies to where you are.

Pollution also is a possible threat to horseshoe crabs. People are using more pesticides on their lawns and farmland, and New Jersey and Delaware are spraying more for mosquito control. As a result, you get more chemicals washing into the water from the urban and agricultural runoff. Junk in the water causes problems, too. Sewage, factory waste, rainwater carrying pollutants from parking lots, yards and streams can kill clams and other animals that crabs use for food. Water pollution may weaken or kill horseshoe eggs and larvae.
http://library.thinkquest.org/J0110020/threat.html

[ledhead36]

Chas I know that area you were walking in. Paco may be right with some of the possibilities he posted. Also around this time of year the water back there gets stagnant. I don't know if you remember this but in the last 10 years we have had fishkills at least 2 times that I recall. Massive peanut bunker die offs. Maybe it has something to do with the lower summer oxygen levels which also kills the fish. Haven't seen any dead peanut bunker or mullet back there this year so I am not certain. That water does get funny though when there aren't a lot of storms.
Also sometimes there are immigrants who fish along that shoreline. They hate the horseshoe crabs when they hook up with them and leave them on the beach.
Same thing with the sea robins. I believe madcaster posted a pic of a dead circle of sea robins in the dead things thread.

[J Barbosa]

For the rest of you shore bound crabbers its time to get your last few crabs in for the season.

With the cooling overnight temps those crabs are one of the first species to begin moving out into deeper water.

My dad and brother were only able to catch six legal sized crabs in three hours...two per hour! Normal catch would have been a few dozen. They went early in the morning after a cool night, the afternoon would have been better.

I've already hung my crabbing nets away until May 2014.

It was a good year for crabbers in NJ!

Look out for a possible crabbing 201 tutorial over the winter.

[buckethead]

I was fishing a few weeks ago and on the beach at night were these little crabs about 2" long. They were whitish and moved with lightning speed. I thought about using them for bait but there was no way I could catch them. Tried for about 5 minutes and gave up. Someone in a tackle shop told me they are called ghost crabs. Does anyone know more about them and have you ever seen them out there at night? Or was I imagining things, lol?

They are very light in color. They also move with lightning speed so you have to plan the shot if you want to get a pic. I have only seen them at night.

http://eol.org/pages/313161/details
Atlantic Ghost Crabs (Ocypode quadrata) are small crabs (up to around 50 mm) with squarish sand-colored shells having margins that are finely beaded but toothless; the claws are white. The space between the eyes is much shorter than the eyestalks. These crabs dig burrows above the intertidal zone on ocean beaches from Delaware (U.S.A.) through the Caribbean and Gulf of Mexico to Brazil.

They are occasionally found north to eastern Long Island and Rhode Island, but are uncommon north of Virginia. Atlantic Ghost Crabs are very active and can often be seen dashing into the retreating surf to wet their gills or to grab scraps of food ("Ocypode" means "swift-footed"), although they will drown if kept submerged.

Young crabs burrow just above the intertidal zone, but adults dig their burrows higher up, sometimes even behind the forward dunes. Burrows have a single opening and descend 0.6 to 1.2 meters at a 45 degree angle. Although these crabs are often out and about during the day, they are most active at night. (Gosner 1978)




Here is a pic of a ghost crab. Was lucky to get it. During one night fishing the full moon.

[hookset]

Can anyone ID this crab shell I found near an inlet? thanks

HOB that is known as the zombie crab. Otherwise known as the empty shell crab.

[J Barbosa]

That zombie crab is better known as a Dungeness crab. They are a west coast crab and not native to the east coast unless your in a supermarket.

And in case you are wondering...yes they are delicious

[baitstealer]

Thanks for the great info here. Was wondering about how crabs shed and if the new or the full moon is a better time for that. Any advice for getting them while they are soft shell? thanks

[clamchucker]

I used to rake them a long time ago. I found that they shed better on the full moon. Some do shed on the new moon as well. If you are looking for soft shells it is best to get them while they are tinbacks and just starting. I would try a few days before the full moon. They are easier and less fragile to handle this way. Then you put them in a saltwater tank and wait until they are fully soft.

[clamchucker]

Here are some other threads on fishing crabs. You might want to take a look at them.

http://stripersandanglers.com/Forum/...m-irresistible
http://stripersandanglers.com/Forum/...abs-sand-fleas

[hookset]

Yes apparently it is a lost art. My uncle did that in the 70's. Got a lot of big fish at night in the summer. From what I remember it was a lot of work though. He had 2 separate salwater tanks he used to keep them in. The second it looked like a crab was going to shed he had to separate it into the shedder tank. Thanks for sharing clamchucker brought back some good memories.

[jigfreak]

Good read on calico and jonah crabs by Jay Mann of LBI at www.theSandpaper.net

From a scientific angle, I can see the LBI replenishment sands ravaging the surfline crab population. Jetty-based species, such as rock and Jonah crabs, had their worlds sanded under. But far more ecologically significant, the calico crabs (Ovalipes ocellatus), aka lady crabs, had the world cave in on them – beneath up to 10 feet of sand.

Calico crabs are one of the most common foodstuff for bass, based on countless stomach content studies. Might it be that stripers, which habitually venture into the surfline to load up on calicos, moved in for a customary meal but found a barren bottom, compliments of freshly dredged sand? Being crafty consumers, they would have quickly zipped seaward to go after bait balls and any deeper-water crustaceans.

If my crabby theory holds true, it could take some time for the bass-attracting nearshore crabs to return. But return they will. Crustaceans are kick-*** when it comes to repopulating after taking a numbers-knocking hit, especially when not being heavily harvested by humans. Calicos have no yum-yum, eat-’em-up value.

As repopulating evidence, there was a hubbub in Harvey Cedars when the initial replenishment seemingly killed off the much-adored sandcrab population. And they were, indeed, gone. I checked. And they stayed gone for maybe a year or two. But, apparently, not all of them perished since they came back with a vengeance, soon recovering to a point of eeriness. A couple summers back, the wet sand of Harvey Cedars came alive with katrillions of sandcrabs, so thick underfoot if felt like the sand itself was wiggling about.

Trivia: Did you know sandcrabs run backwards after you dig them up? Yep.

The sandcrab bounce-back reflects a population pendulum effect, which comes about after a highly-reproductive species is suddenly and drastically reduced. I’ll wager that calico crabs can perform just such a bountiful bounce-back, which might coax bass back to traditional, near-beach crab-fests.

As for jetty-based rock and Jonah crabs, their return is on rocky ground. While many plowed under jetties will return to some degree, recruits to repopulate those rocks, i.e. survivors from the replenishment, will be in short supply. Any long-term recovery for such jetty/rock-based species will likely come from free-floating crab larvae.