[BlueChip]

The Blue Crab Year -
The Search for Megalops – September 19, 2011
Report #15B – Program Report #4
You do not need to be a scientist to report!



The Study Design
Proposed for October 1, 2011

The initial start of the project will be the selection of various coastal sites in which to investigate the presence or absence of blue crab Megalops. The sites will represent areas known to contain adult or small crabs. The start of the project is to locate areas and determine if a habitat pattern/preference can be established. It is just a presence/absence study to find Megalops; a more precise survey sampling program is a future expansion dependent upon initial findings.

Thus the first step is to locate areas that might contain blue crab Megalops. The second step is to have students and volunteers survey some areas. A few years ago I attended the Project SEARCH volunteer winter training workshops held at Hammonasset State Park with Russ Miller in the Meigs Point Nature Center. I was very impressed with the volunteer training workshops and this winter similar workshops will be held at the Sound School.

Where to Look

Much of the available life cycle habitat studies have been done for the Chesapeake Bay region and southern areas. From published articles evidence indicates that Megalops can find shelter in a wide range of habitats, the most important being estuarine bottoms that contain shell or live shellfish especially the soft shell clam (steamer) Mya between low tide depth of 1 to 2 feet..

A second habitat/environment type is areas with good tidal circulation and sufficient oxygen (shallow 1 foot or less, not stagnant) and perhaps edges of eelgrass also. It is the edge of vegetation or the transition from non-structure smooth areas to habitats that have relief such as shell may perhaps be the best areas to look. It is also suspected that the same areas will contain worms, small shrimp species and sets of shellfish. Reports in some southern research papers speculate that the best Megalops areas often contain small and newly set soft set (steamer) clams (Mya). It is also thought that acidic bottoms – those with low pH and low oxygen are hostile to the Megalops stage. This habitat preference is one of the studying/monitoring objectives.

Proposed Sampling Methods

The type of gear proposed is a modified “D sampling net” with a very fine mesh net. The D net looks like a regular fish landing net with a flattened edge. It looks like someone pushed on it making the bottom edge flat, making it look like a letter D with a handle opposite the flat edge. The mesh is very fine because to the naked eye, a blue crab Megalops are very small, about the size of a flake of ground pepper.
In the Project SEARCH study, the freshwater stream currents direct riffle dwelling organisms into the collection net (device). To loosen these fresh water organisms a series of foot pounding (called kick stops) are employed to dislodge organisms into the current flow and then into the net. In the marine environment we don’t have that flow all the time to concentrate specimens so a different sampling procedure might work. A modified clam harvesting device (clam pounder) a descendant of the century old flounder pounder used in Niantic Bay in the 1880s may assist in collection. Rather than kicking the bottom a plumber’s helper is attached to D net handle and plunged three times. The small depression is then scooped with the D net. The rubber plumber’s helper can be purchased at hardware stores and attached with a metal screw operated pipe clamp. This device looks a little funny at first- a wood handle with a sampling net at one end and the plumber’s helper on the other. But, it is effective at suspending sub tidal organisms when employed as a University of Massachusetts Cooperative Extension agent in the 1980s I found it to be quite successful.

Sampling Protocols / Operations

Areas would be surveyed every two months, two samples about 1 meter apart. All samples should be 12 inches deep at low tide (this may change after the first fall surveys). Because these organisms are small, soft bodied, they are fragile and could break down before they can be keyed out. To help preserve the samples, the salt water will be stabilized and frozen.
To collect the sample, the organisms are so small they will cling to the collecting net, so a bulb type turkey baster will draw up a portion of a reduced in the net sample and deliver it into a collection jar. Don’t be surprised if you’re soon surrounded by silversides and killifish, bottom disturbances to these species are like ringing the dinner bell. But ample time should be available before visitors arrive in large numbers.
At this point, the sample will be stabilized most likely with an over the counter calcium tablet to buffer the sea water. The fragile Megalops body tissue is very soft and an acid water sample could possibly dissolve it. Samples can then be frozen and stored until keying out? Not certain, is this practicable?

Sound School Site – Control / Protocols Development

The Search for Megalops will involve several Sound School teachers; we plan to establish a sampling station at the Sound School as a Capstone Project. Taking a sample should only take a few minutes. A photo/narrative outline will be available December 1 and key protocols by November 15. A genetic study will be started with Chesapeake Bay researchers to see if the genetic differences or similarities can be established and interest in hatching/spawning some sponge crabs as part of an Aquaculture Biology class. A senior class aquaculture life teacher has planned to offer his senior students to look a blue crab habitat in terms of climate change.
We will also work with interested Guilford, Madison and Old Saybrook marine science classes with survey sites and sampling techniques; the Bridgeport Aquaculture School and the new Groton Marine Science Magnet School has expressed interest also. All of our information will be online and available by interested public, research or volunteers.
The project will commence in early September and sampling should start October 1st. A public workshop forum is now being discussed in which student projects/papers and PowerPoint’s™ will be presented to staff, researchers and members of the environmental community that would be scheduled sometime in the spring.

Equipment

Net- http://www.bioquip.com/search/DispProduct.asp?pid=7410R

The sampling net we are considering is the BioQuip™ heavy duty aquatic net (no trade or product endorsement implied). They are the “D” shaped nets that allow greater bottom sampling area/contact. BioQuip™ makes a net from heavy cotton and polyester canvas, stitched with non rotting screen. They feature a white mesh (Nytex) screen placed about 8 inches below the canvas rim. Since the Megalops are very small, a bag with 150 micron screen is thought to be the best 7412-DN model.

Since the organisms are very small drying the net will have organisms clinging to the canvas and screen. It might be easier to do a water to water transfer by partially drying a corner of the net, but not completely. A suction device (it looks like an old fashioned turkey baster could be an option) could draw up a liquid sample and direct it into a sample jar or bag. Sea water is alkaline about 8.1 to 8.4 but samples after a heavy rain (fresh water tends to float over salt water) might be acidic so the addition of an over the counter calcium table could stabilize the sample until it is frozen. This is just one possible stabilization method at this point.

The Pounder-
This device dates back to the cold period or climate shortly after the Civil War when Connecticut was in a very cold decade in the 1870s. The coves would freeze up in eastern Connecticut including Niantic Bay. Winter flounder spear fishermen would cut holes in the ice in two basic areas: soft sediment or eelgrass for overwintering eels and clam beds for winter flounder. A large pole and wood rack or basket at the end would be pummeled into the bottom through the ice, dislodging worms, clams (breaking some no doubt) but attracting winter flounder (chumming). Some retired bay scallopers told me about their fathers using such a device- a precursor to the modern chum pot. After a few minutes, the flounder spear would be sent down the hole (you can still see these spear’s today for sale along the shore in antique stores). The basket soon found its way to a simple flat metal plate disk and the blacksmith shop. It too was fitted to a long pole and looked like a long plumbers helper – plunger. In the 1960s, this device was modified to catch sub tidal soft shells “steamer” clams and plunging for clams was frequent on Cape Cod and Rhode Island in the 1980s.

According to Phil Schwind, in a brief Chatham meeting 1982, populations of soft shells retreated to subtidal areas on the Cape in the 1950s and 1960s. It was thought that severe freezes then reduced the exposed tidal soft shell populations beginning in 1940s, the washing of clams in the subtidal areas began and the pounder became the plunger. It soon followed by trial and error that salt ponds contained significant soft shell clam populations. [This is not unlike some of the historical accounts from the Great Island soft shell clam flats off Old Lyme (1930s) of subtidal harvest with a special offset shovel and an old Colonial garden screen, back then called a “riddle”. CT soft shell production would soar during the Great Heat (1890-1920) but drop considerably in the colder period of 1960s.] In a 1970 booklet titled the Clam Shack Clammer (May 1, 1970 Printer Charles Thompson) Phil Schwind lists the plunger on page 35 as shellfish harvest equipment. He is generally credited with keeping this old method of subtidal soft shell clam harvest current from the past century.


The modern day plumber’s helper can still be purchased at most hardware stores and together with a screw fitted metal pipe clamp, it can be reinstalled at the end of the D net. So, the “pounder” and collection net is one device (as with catching clams years ago). You don’t’ need to plunge more than two or three times creating a slight depression (not a hole) – the organisms should settle in the depression and then collected with the D net end.

Cost equipment list –
o One 7412 DNM Aquatic net 12” D shape 150 micro mesh
Nylon Bag ($68.20) BioQuip™
(No product or trade endorsement implied). $68.20
o One metal screw fitted pipe clam (hardware store) $1.49
o One flexible plumber’s helper plunger (hardware store) (the existing wood handle is not used) $7.95
o One bottle of calcium supplement (drug store) $4.95
(Sample stabilization)
o Collection bottles/bags (various) (for freezing until collection) $10.00-$15.00
o The total cost (excluding microscopes and bioscopes to examine samples) is about $100.00.
o It is suggested that monitors wear “knee high” boots.
o You will need a microscope to examine samples.


If you are interested in becoming a Megalops monitor, please email me at the Sound School (tim.visel@new-haven.k12.ct.us). Although several educators have expressed looking for Megalops now and can do so. (I’m surprised at how many people already have microscopes at home.) I suggest workshops for interested monitors this winter. That way in the spring we may be able to assess surveyed Megalops. There is also a possibility that all Megalops monitors will need to be listed on a Scientific Collector Permit.



For now please continue to send in those observations and any locations of female sponge crabs. Even if it’s just one sponge crab, every observation is important. I’m especially interested in reports of very small blue crabs which should appear the end of August.

The continued reporting by many new and veteran crabbers is so valuable to our study and I thank each for their contribution this spring and summer; I hope they continue to send in reports to me.

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 – email to: susan.weber@new-haven.k12.ct.us

[Timmako78]

hi my name's tim, I'm interested in helping out with the blue crab study. just let me know what is in the details thank you tim barbour