Wednesday, August 24, 2011

CT blue crab reports #14

This post is the first that I will be posting of a series of reports about blue crabs in Connecticut. The Search for Megalops is part of a Project Shellfish/Finfish Student/Citizen Monitoring Effort Supported by a 2005 grant to The Sound School from the National Fish and Wildlife Foundation grant #2005-0191-001. Program reports are available upon request. For more information about New Haven Environmental Monitoring Initiative or for reports please contact Susan Weber, Sound School Adult Education and Outreach Program Coordinator at susan.weber@new-haven.k12.ct.us.

I will post reports 1-13 soon. Thanks to The Search for Megalops for making these available.



The Blue Crab Year -
The Search for Megalops – August 19, 2011- Report
#14
You do not need to be a scientist to report!

Reports 1 to 13
are available – email Tim Visel at tim.visel@new-haven.k12.ct.us

Three
to 4 inch crabs reach legal size; run and catch transitions now
evident;
Heavy rains again cause concern for small crabs;
What about the
other crabs?
Do all crab Megalops look alike?

The run has
changed in all sections as these 3 inch to 4 inch crabs have shed into legal
sizes. The western run is now 70% legal size, the central and eastern,
about 50% legal size. It is thought that what happened last year cooler
eastern temperatures slowed growth, so the western warmer areas would have a
longer “growing season”. For example last summer the run at the Essex Town
Dock August 30, 2010, was 95% legal while crabbers in the Pawcatuck River had a
run of 20% legal. The eastern water temperature was several degrees cooler
all summer long. The smaller spring 1.5 inch to 2 inch crab is now 3 to 4
inches while those June 4 inch crabs are now legal. As such catches
generally have increased, we now have only 2 sizes, legal and up, and 3 to
4. What we need to see is those new 1 inch crabs, perhaps 1.5 inches by
September 1st. Those small crabs should appear very shortly and in very
large numbers (if the Megalops set was large).

At the same time
Connecticut, especially the western sections have experienced another huge
rainfall event, August 12th to 14th. Some sections received 6 inches or more of
tropical like rainfall. Some central reports indicate large numbers of
crabs leaving small areas at low tide by the hundreds. It could have been
low oxygen or fresh water toxicity or a combination of both (see blue crab
report #12, August 2). It’s too early to tell but such heavy rainfalls can
kill small crabs or sweep them from estuaries, and unlike March/April, crab
predators are numerous, especially large numbers of fluke. The worst case
scenario is that we start to see dead small crabs on the shores of salt ponds
and creeks. Those small crabs are very vulnerable to oxygen deficiencies,
and heavy rainfalls. They might even be caught in those small mesh bait
minnow seines in shallow areas.

I believe the very small
crabs are in those shallow marsh ditches (many old ditches from previous
mosquito/malaria control program of the last century) and the upper reaches of
creeks. Kayakers might be the first to see these very small crabs and have
obtained a few reports from kayak observations and they were very valuable, so
you don’t need to be crabbing to report, any observations of small blue crabs
would be a great help.

If any crabbers notice any dead or washed up
small blue crabs (should be about an inch to 1.5 inch across) please send in a
report- general location – shallow shore, marsh, creek central, east, west, etc
would be appreciated; and of course no need to identify the exact location.

Any female crabs or especially female egg bearing sponge crabs,
reports would be helpful. The past few days’ crabbers have been mentioning
the absence of female crabs, everyone except for a couple of reports mention
catches as nearly all male.

As I watched blue crabs and its
population dynamics this summer, questions have been asked about species -- not
that much is known about other crabs or populations other than the paper I
referenced a few months ago: Spider Crab Podding Behavior and Mass Molting
(DeGoursey and Stewart, 1981). This often brings up the question of other
edible crab species here and one that has come up many times this summer.
In several visits to Niantic Bay, for example, I have talked to and watched
several families actively engaged in catching green crabs as food. Green crabs
(Carcinus maenas) – green males and red/orange females. From time to time, I
have heard this before, but my conversations this summer have been different; it
is a fishery although small; it is a food catching activity.

In my visit to Niantic Bay (River) this summer I was amazed at the
size of green crabs – they were huge. The green crab, a species native to
northern Europe arrived about a century ago and devastated the soft clam fishery
(steamer clams) in New England. It is still a serious predator of small
clams and oysters and also predates upon bay scallops. It is a favorite
bait (food) of black fish (tautog), and I’ve spent many hours harvesting them
for local bait and tackle stores, and also for my fishing. So it was
surprising to see such delight in landing a huge green crab (when I used to toss
them back) and throwing away the size desired for blackfish bait; when I asked
about it – the response was, “too small, let it get bigger”. The five
gallon pail was half filled with gigantic green crabs. When I explained I
was looking for blue crabs, I was told these (the green crabs) were
better! I wasn’t that surprised, because I had seen similar crabbing off
the Point Judith Pond Breakwaters in Rhode Island years ago.

In the
Open Sea, by Sir Alistair Hardy (1959), he mentions this green crab fishery in
England on page 144: (The green crab is invasive to our waters, an import from
Europe a century ago) in the Channel Islands. The edible crab – the Rock
and our Jonah crab is also described by Hardy (pg 145) as a fishery and we have
two similar species (Atlantic Rock Crab – Cancer irroratus – reddish brown) and
(Jonah Crab – Cancer borealis – red to purple top). In Maine it is a large
fishery (picked crab meat) called Peekytoe. Rhode Island from time to time
sells large rock crabs as an incidental catch to lobstering; also a deep water
species called Red crab is a huge crab and very good eating (Chaceon
quinquedens). These crabs however do not keep as well as lobsters and need very
cold seawater systems. (See Sound School publication #21 on our website: http://www.soundschool.com/directory.html
titled Gravity Fed Self Regulating Bio- Suspended Solids Pillow Filter for Crab
and Lobster Tanks). Other native crabs are also edible, when working for
the University of Massachusetts, a friend invited me to an evening meal in his
home town of New Bedford. It was a wonderful Portuguese meal, a
fisherman’s stew served with whole (but cleaned) lady crabs. Sometimes called
the calico crab, they have spotted shells, smaller than blue crabs but with very
sharp claws. These are the same bad attitude crabs that I ran into
numerous times while swimming in Madison, so it was of interest to see them
cooked and they were delicious. I found out that such whole crabs were
considered a delicacy and some modern pasta sauce dishes include whole blue
crabs.

But the lady crab (Ovalipes ocellatus) was especially
delicious and tasted more like lobster than crab. I was very surprised
having seen lady crabs along the sandy beaches so many times. I would
suggest however extreme caution picking these crabs up, it’s like they are
double jointed and can bite you quickly with very large claws. I feel they
are faster than blue crabs and more dangerous.

Other crabs are
also edible, the green crab: males green, females red/orange (Carcinus maenas),
the Atlantic Rock crab, (Cancer irraratus) - reddish brown and the Jonah crab,
Cancer Borrealis, red to purple top.

Of the two “ground
crabs” Jonah and Rock crabs, it is the Jonah crab that is the larger of the two
and is the one harvested in Maine, Rhode Island and Massachusetts. At this
time the Maine crab fishery has grown in importance and now some 2.5 million
pounds of crabs are harvested yielding several million dollars. I had a chance
to visit Maine last week and had a Graffam Brothers Seafood, Rockport, Maine
crab roll and it was excellent. Rhode Island lands Jonah crab and from
time to time, a deepwater red crab. If you ever have a chance to taste red crab,
do not turn it down; it is also delicious (Chaceon quinquedens). The
landings of Rock and Jonah crab are thought to be small in Connecticut.
Now for large spider crabs, (Libinia emarginata), yes, they are edible, in fact
very good. After pulling thousands of them from our wooden lobster traps
with my brother Raymond (1970s), we decided to try them. They are not the
smaller crab found in the shallows close to shore; these 4 to 6 inch diameter
crabs were in 50 to 70 feet of water. We picked out a dozen of the largest
crabs; they look like a smaller king or snow crab. First, forget the
legs/claws; the only portion that contains meat is the body section. Also,
don’t think you can boil them like lobsters and blue crabs, their shells are not
clean like blue crab or lobsters, but very muddy at times and covered with
seaweed. We tried cleaning them (shells) but that didn’t work, well what
did work was cleaning the crabs before cooking so you just boil the cleaned body
sections. The picking was a challenge, the body sections are thick, but
large hard shell crabs were packed with meat and when prepared in a crab salad,
was very hard to distinguish from blue crabs, and in fact, it was very
good. The marketing of these large “spider crabs” was a failure however,
and this experiment was only practiced in years in which blue crabs were scarce
and we wanted some fresh crab meat sandwiches.
Note, before crabbing in other
states, always be sure to check fishing regulations. Most states have some
regulations, size, season and permits. For example, it looks like from
some of the Internet material the state of Maine issues both a recreational and
commercial Jonah crab license -- best to check before crabbing.
Connecticut, for example, does issue commercial blue crab licenses with the same
gear provisions for a fee, while CT recreational crabbing remains no fee, free;
same season, same sizes, etc.

One interesting section in Sir
Hardy’s book, the Open Sea, Fish and Fisheries is a description of the
Rock/Jonah crab fishery and one that sounds very similar to a blue crab, almost
incredibly so, and one that doesn’t really fit Rock or Jonah crabs as swimming
crabs, but he describes their behavior and habitats. (If you look at these
crabs, they don’t look at all like the swimming crabs, and it’s hard to imagine
them mass moving but they do).

“The crabs are actually more
inshore animals in summer than in winter. In autumn, they migrate offshore
into deeper water where the females extrude their eggs and attach them to their
small abdominal appendages, in the spring they return to shallow water carrying
their eggs which hatch in June and July into little Zoea larvae. In
addition to this to and fro migration, some have been shown by tagging
experiments to migrate considerable distances along the coast, journeys of 90
miles have been recorded.” (pg. 145)

It’s hard to imagine a Rock
or Jonah crab as moving such distances, they look more like a tank than a race
car, but they do. And if something that looks like a tank can travel such
distances what about a crab that is nicknamed “beautiful swimmer” and blue crabs
can really swim and fast. I can recall last summer crabbing at night and
watching them swim by on the outgoing tide and they were moving! I hardly
had time to pick up the crab net and they were gone.

At this time
I’m getting more and more reports of large deepwater totally male blue crab
populations – moving – in 15 to 25 feet deep water. The boaters with crab
pots are doing quite well and good catches of large male blue crabs in many
areas. Catches are being made in the 15 to 25 foot river channels, some
dense concentrations in the west and occasional good catches in the Mystic
River. The shore areas especially shallow water remain slow – it could be
just too warm, not certain. What is interesting is the absence of female
crabs; they are rare in recent catch reports.

Do all crab Megalops
look alike?

I had a crabber ask that at the Sheffield Town Dock in
Old Saybrook and it’s a great question (and I might add, one of a number of good
questions this summer). I don’t know; I have seen many more green crabs
with “sponges” so they must have a Megalops set, and lady crabs also; to be
honest, I’m not certain. We might be seeing 3 or 4 different types of
Megalops so we will really need that online video key. We might be able to
short cut this effort by looking for habitats that blue crab Megalops prefer,
shallow bands of sand that contain living immature soft shell clams,
steamers. There is some evidence that the blue crab Megalops seeks out
this habitat, the movement of the clams may leave chemical clues or waste
products or siphon “noise” but numerous references mention Mya beds or estuarine
shell as ideal habitats.

Most habitat references indicate it’s the
shallow areas, the ones with cover, eelgrass perhaps other submerged vegetation
that will allow the maturing crab to hide, or burrow. This zone is also
frequented by two very aggressive predators, the Killifish fundulius species and
sand shrimp, Crangon septemspinosa. It is thought that the blue crab
Megalops seeks out or survives best in areas with estuarine shell, both clams
and oysters to escape these predators.

One word of caution, it is
expected that in searching shallow areas for crab Megalops, monitors will
discover occasional sets of shellfish, oyster, soft shell clam (steamers) and
perhaps quahogs (seed) as well. Although it is important to note the
presence of such clam sets, shallow areas along the coast are usually closed to
shell fishing and need a permit to harvest and retain them in the open or
certified areas. Shallow areas even beaches can have high counts of
bacteria after heavy rains and shellfish living in such waters do not meet state
and federal harvest regulations. Many crabbing areas have signs notifying
the public that shellfishing is not allowed. This concern has been the
subject of some lengthy discussions at our Long Island Sound Habitat Restoration
Committee, that the public is now largely unaware of a substantial Connecticut
soft shell clam resource (the sets the past few years have been very
strong). Recent visual surveys off the Town of Westbrook have shown clams
in many areas.

But at the same time we have seen an increase in
blue crabs; we have seen soft shell clams sets increase also, with the ever
mentioned habitat association between the blue crab and Mya (steamer clams) and
warmer Long Island Sound temperatures; it is a habitat association that is hard
to ignore. A century ago here in CT between 1890 and 1920, summers were then
particularly hot, blue crabs and steamers did quite well during this period. The
soft shell clam sets in Clinton Harbor, lower Hammonasset River in 1900-1902
were some of the heaviest in our fishery history. The 1898 statewide
oyster set was the set of the century and blue crabs became very prevalent along
our shores. Rhode Island officials noted this also in Narragansett Bay a
century ago and commissioned a special study to investigate the sudden increase
in soft shells and blue crabs in 1905. The RI report printed in 1906
details the increase of soft shell clam sets, a surge in blue crabs but also
dramatic drops in bay scallops and lobsters. The thirty-sixth annual report of
the Rhode Island Commissioners of Inland Fisheries, January session, 1906 E L
Freeman & Sons State Printers (336 pages) contains this section- The
Continued Examination of the Physical and Biological Conditions of the Bay
[Narragansett] begun in 1898, page 106-107.

“On Cornelius Island,
in Wickford harbor, the (soft) clams set extremely thick in 1904. In the
protected area, the clams were so thick at the time of setting, that there was
not room for the growth of all of them, and so, as they increased in size, many
were forced out upon the surface, so that in a short while, the ground was thick
with (dead empty) shells --- Another case in point was observed at Greene’s’
Island on the east shore of this island is a long flat which in 1901 was set so
thickly with clams that 7,910 were counted in a single
shovelful.”

Clam / oysters (all shellfish) collected as part of the
Blue Crab Study should be noted but not retained, and returned as soon as
possible to the location sampled.

For now please continue to send
in those observations and any locations of female sponge crabs and smaller
crabs. Even if it’s just one sponge crab, every observation is
important.

Observations this year will help guide the survey
methods for next year.

Every observation is important you do
not need to be a scientist to participate!

The Search for Megalops
is part of a Project Shellfish/Finfish Student/Citizen Monitoring Effort
Supported by a 2005 grant to The Sound School from the National Fish and
Wildlife Foundation grant #2005-0191-001.

All observations are
valuable; please email them to me at tim.visel@new-haven.k12.ct.us.

Program
reports are available upon request.
For more information about New Haven
Environmental Monitoring Initiative or for reports please contact Susan Weber,
Sound School Adult Education and Outreach Program Coordinator at susan.weber@new-haven.k12.ct.us

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