Marking Period 2 Calendar of Work and Due Dates

Due Dates:

11/27 - calendar of dates due

12/2 - developmental work/plan of procedures

12/16 - press release

12/18 - initial construction analysis

1/15 - outline for formal presentation

1/16 - formal presentations begin

1/20 - final construction analysis

1/23 - mentor contacts

4 days after presentation - presentation reflection

Working Plan*:

11/26 - develop schedule of work for the marking period

11/27 - work on plan of procedures; figure out what supplies and materials to be used

12/2 - finish POP and developmental work

12/3 - find distributors of materials needed 

12/4 - create list of possible places to buy items

12/5 - contact mentor to find possible suppliers

12/6 - begin working on the press release

12/9 - continue press release

12/10 - continue writing up material purchases

12/11 - begin construction of tank

12/12 - continue tank construction

12/13 - let mentor know about press release; test tank construction

12/16 - finalize and turn in press release

12/17 - work on building tank

12/18 - work on building tank

12/19 - ensure everything is working properly in the tank

12/20 - collaborate with Mr. Trimble to ensure proper connections

12/23 - contact mentor to update on tank construction

12/27 - work on building tank

12/30 - test the tank so far; continue building

12/31 - work on building tank

1/1 - work on building tank

1/2 - work on building tank

1/3 - work on building tank

1/6 - test tank

1/7 - work on building tank

1/8 - work on building tank

1/9 - work on building tank

1/10 - ensure Mr. Trimble's parts properly match my own

1/13 - read over rubric for formal presentation; ensure all needed aspects are completed

1/14 - construct the outline for the formal presentation

1/15 - finalize and work through the formal presentation outline

1/16 - formal presentations

1/17 - formal presentations continue

1/20 - first possible day to turn in presentation reflection; formal presentations

1/21 - formal presentations; work on midterm

1/22 - work on midterm

1/23 - work on midterm

1/24 - work on midterm

1/27 - midterm due

 *subject to change

Testing Procedures

The purpose of completing this project, for our team, is not only to help horseshoe crabs as an entire species, but we are also building this tank for the Seniors in the Class of 2015 and beyond to use in MAST's Oceanography course. A successful tank will be able to raise at least 20% of the 100 horseshoe crabs which will be placed in the tank, while also benefitting the scientific community by advancing our knowledge of the species. A complete system - which includes Mr. Trimble's water and nutrient systems - will be constructed and implemented, and if the entire system can constantly and consistently maintain flow of the necessary nutrients and water while also maintaining a stable connection throughout the tank the solution will be considered a success. (more information can be found about the functions of the tank here)

Throughout the process of this project the design of the tank will undergo many tests to ensure the best product is created. Starting at the beginning the four alternate designs will be compared to find the best solution. From this decision there will be tests comparing materials, water volume sizes, substrate choices, system integration with Mr. Trimble's systems, as well as the final test of the solution once construction has taken place and the tank is ready to be used. Most of these tests will be performed by myself along with the rest of the team, but along the line my mentors will be assisting in the tests and the final solution will be tested during implementation of the tank by the Oceanography class next year. In general, these tests will take place in the Systems Engineering II classroom with exceptions being any time emails are sent and the final solution which will happen in the NOAA lab on Sandy Hook.

Testing Type: Comparison
Testing Stage: Preliminary
State of Solution: Alternate Solutions
Condition of Testing Stage: Preconstruction on paper
Tools and Equipment: the drawings of solutions

Testing Procedures:
1. Lay out the four designs
2. Using the specifications, compare the designs
3. Decide which solution best fulfills the specifications


Testing Type: Exploratory
Testing Stage: Preliminary
State of Solution: Paper drawing
Condition of Testing Stage: Preconstruction on paper
Tools and Equipment: drawing, mentor, future user

Testing Procedures:
1. Set up a meeting with the Oceanography teacher at MAST
2. Show her the drawing of current solution
3. Ensure design incorporates all necessary design aspects and fulfills the needs of the project
4. Make changes as necessary


Testing Type: Validation
Testing Stage: Preliminary
State of Solution: Dimension Specific Drawing
Condition of Testing Stage: Preconstruction on paper
Tools and Equipment: drawing, Mr. Trimble's drawing, Mr. Trimble

Testing Procedures:
1. Meet with Mr. Trimble and compare drawings
2. Ensure the measurements of the two drawings completely integrate
3. Alter as needed


Testing Type: Exploratory
Testing Stage: Secondary
State of Solution: Drawings and Research
Condition of Testing Stage: Materials
Tools and Equipment: Notes on materials, possibly samples of materials

Testing Procedures:
1. Compare possible materials among each other
2. Using information gathered, decide which materials would best accomplish the needs of the tank to ensure stability and usability


Testing Type: Assessment
Testing Stage: Secondary
State of Solution: CAD Drawing
Condition of Testing Stage: Preconstruction
Tools and Equipment: CAD Drawings, project specifications

Testing Procedures:
1. Compare the current solution with the specifications of the project
2. Going down the list, look at the details of the tank to make sure each specification is fulfilled


Testing Type: Assessment
Testing Stage: Tertiary
State of Solution: Post Construction Non-implemented
Condition of Testing Stage: Dry and Empty
Tools and Equipment: constructed tank, specifications, weights, water

Testing Procedures:
1. Examine the constructed tank to ensure the pieces are sturdy
2. Test all joints for leaks
3. Apply pressure to ensure the joints will hold under the pressure of the water, sand, and crabs.


Testing Type: Validation
Testing Stage: Final
State of Solution: Completed
Condition of Testing Stage: Implemented, containing crabs, water and sand
Tools and Equipment: full tank, all materials

Testing Procedures:
1. Completely implement all variables in the tank
2. Observe how the crabs begin to integrate into their new environment
3. Decide if the tank is working as needed, if not halt all processes and return the crabs to their holding tank

Survey for Assessment:
1. Do the 100 crabs fit comfortably?
2. Are scientists benefitting from the use of the tank?
3. Is the environment of the tank similar to the current state of the natural environment of the horseshoe crabs?
4. Is the tank holding stably?
5. Is the water connection water tight and properly fitted?
6. Is the water flowing constantly?
7. Are any of the parts being negatively effected by the salt water?
8. Are the horseshoe crabs healthy?
9. How clean is the tank overall?

Developmental Work

 2D VIEW

 



3D VIEW



 EXPLODED VIEW

Rationale

The four tank designs talked about below were all created for the purpose of raising horseshoe crabs in a lab environment. These designs focus on the main structure and functionality of the tank, but all must properly integrate with the water flow system Mr. Trimble is creating. All tanks are expected to perform at a certain level and through the process laid out here the flaws and strong points of each design will be analyzed and used to determine the best tank. For these designs to work they will need to be beneficial to the survival rate of the crabs as well as the study of the species for human purposes. Efficiency will be achieved when excessive amount of water or additional nutrients will not be necessary. By raising a significant number of crabs without a high amount of waste of water or other resources we will know the tank works well and efficiently. As per the design of the project, our tank must work off of a closed system of water flow to eliminate the potential for contamination, but there must also be aspects of the tank which will cause constant flow of the water within the system while also taking into account the potential for things like water leakage or over filtration. The system will be considered a failure if there is no benefit to either the horseshoe crabs or the scientists studying them while they are in captivity.

Design 1: Cylindrical Tank
Being the first design I created, this tank is naturally the simplest design of the four. There is a very basic connection to the water filtration system in the sides of the tank and a large observation window in the front of the tank which would be used to watch the activity of the crabs throughout the day. This tank appropriately takes into account the need for constant submergence by the young horseshoe crabs. The simplicity of the design is easy to replicate, the only complications coming from the transition between solid fiberglass and plastic/acrylic to make the observation window. Since this design is one of the larger tanks, the cost of the fiberglass along with the piece of plastic or  acrylic would have to be taken into account along with any tools needed to created the desired shape and connections to ensure a stable and water tight product. If created properly the horseshoe crabs will benefit from having a stable and controlled environment where they will be taken care of during one of their more vulnerable life stages. The scientists will benefit from a proper product by being able to watch the horseshoe crabs in their daily life.

Due to the shape of the tank there is certainly a level of stability not achieved in a shape with more joints and corners. Having a cylindrical shape means having only one seam at the bottom of the tank and along the edges of the observation window, which can become completely water tight with the proper adhesive. Though maintaining structural integrity under the pressure of water is necessary in this project, that is one of the only aspects this tank has that greatly benefits both the horseshoe crabs and the users. The tank only barely resembles the natural environment of the horseshoe crabs and may not properly prepare them for release post-captivity.

Design 2: Shore Tank
With a better understanding of the natural environment of the horseshoe crabs, my next tank design was created. This design was the first design to take into account the natural slope and other aspects of the environment of the juvenile horseshoe crab. There is a section of dry, open sand at the top of the tank onto which the crabs can crawl if desired. This mimicked shore area would also allow my team to imitate the tides of the area where the horseshoe crabs will eventually be released. Again, this tank has a very basic connection to the water flow system, but this is something that could be easily altered as the most important parts of this design are the structural aspects like the sloping bottom. By including the sloped bottom of the tank, the horseshoe crabs become more accessible because with a shallower depth the scientists who will be working with the crabs will be able to reach in to grab the juveniles without submerging their entire arm. Due to the simple box shape the walls of the tank take on the design is easy to reproduce, the only confounding factor being the odd slope of the bottom (this is dealt with in Solution 3: Sloped Tank). The costs considered with this tank will need to be simply the materials (acrylic and adhesive) and tools (such as saws) needed for creating the tank. Overall, this tank will be a better option for raising the horseshoe crabs than the previous design would have allowed, because there is a better representation of the natural environment as well as a more ergonomic design for the scientists who will be using the tank for studying the species.

I find with this design that there is a better representation of the natural environment of the horseshoe crabs which makes this design a better choice than the previous tank. However, over time and after creating further designs I have found some flaws in this design. First off, the large portion of dry sand at the top of the tank, which is a focal point of this design, would be virtually useless during the age range the crabs will be in captivity. Generally, horseshoe crabs only make use of the intertidal zone when they are mating and laying eggs which is something the young crabs will not be doing. Even though the crabs will not make use of the dry sand, the availability makes the possibility of tide simulation feasible. Another obstacle faced with this tank as well as in the next three designs is the tendency of sand to settle; this will be a problem with the sloped bottom of the tanks where we expect the sand at the top of the slope to seek the lower parts of the slope.

Design 3: Sloped Tank
As a continuation and alteration of the previous solution, my third design came into being. This tank is a combination of the previous tank and the tanks which they are currently using in NOAA, as this is where the tanks will be used. There is a central drainage pipe where the excess water will flow through into the filters to then be put back into the tanks. I continued with the idea of the sloped bottom in this tank, however I altered the idea so the slope is less dramatic and easier to create and then reproduce. The slope will again allow for those using the tank for scientific purposes to have easy access to the crabs without needing to fully submerge their arm. This design, however, has the entire area of the tank floor submerged instead of keeping a section dry. By including this change there will be more area for the crabs to live in while keeping the benefit of a better simulated habitat.

Since this design was created as an alteration of the previous design, the changes made allow the tank to better fit into the NOAA environment while maintaining a simpler and more easily reproduced shape. The tank still has a good simulation of the natural environment while also incorporating a simpler and more reliable system for water flow. The potential problem with the water drainage in this tank is the possibility of horseshoe crabs (if they were to swim) getting caught in the drain. The drainage system also may not fully cause the water towards the bottom of the tank to filter and drain.

Design 4: Compartmentalized Tank
The final solution that has been made for this project is a tank which could be looked at as a combination of designs one and three. The basic shape of the first tank design was kept, but modified to better fit our needs. Center drainage and sloped bottom of design three was kept and combined with the shape of the first tank. Each compartment of this tank is meant to hold 20 of the 100 horseshoe crabs and the tank as a whole will hold all 100. This tank will save lab space as well as provide the horseshoe crabs with the best simulated habitat we can create. In the center drainage pipe there is one large slit where we want the water level to be maintained along with a series of small holes which will allow the water towards the bottom of the tank to trickle out and be filtered. As a safety, the top of the pipe will be open in case of overflow. On top of reach partition, small pipe holders are in place to hold the pipes of the water flow system. We tried to keep the design as simple as possible while also taking into account all the needs of the tank to work properly and also the needs of the horseshoe crabs.

This tank is the most designed tank with the most thought put into the structure. There are certain aspects of this design, such as the sloped bottom and the trapezoidal shape of the walls which add a bit of difficulty to the design. However, these things are necessary for the proper function of the tank. By using this tank, the space within the lab will be saved or better utilized and the partitions within this tank allow for a few different variable to be tested among the separate sections of crabs.

	Design One	Design Two	Design Three	Design Four
Has space to raise 100 crabs	4	3	4	5
Has potential to raise survival rate	4	4	4	4
Is beneficial to studying the species	2	3	4	4
Replicates the natural environment	1	3	4	4
Is stable under pressure	4	3	3	4
Properly connects with water systems	1	3	3	4
Able to survive constant exposure to salt water and live crabs	3	3	4	4
Water/leak proof	2	3	4	4
Is replicateable	3	2	4	3
Total	25	28	34	36

*on a scale of 1-5

After taking into account each specific need the tank needs to fulfill and comparing the tanks to each other, I have found that the compartmentalized tank will work the best in raising the young horseshoe crabs by mimicking their environment properly, but the design is also ergonomic for human use in a lab. Design four best allows for comfortable living conditions for the crabs, while also giving the NOAA scientists a tank which they may use to study the species and possible help further save them. This tank, though maybe the hardest to construct is thoroughly thought out and "safeties" within the design have been created to ensure constant, up to par function of the tank. This is, therefor, the best option for us to move forward with.

(to see the tank designs follow this link: http://habitatforhorseshoecrabs.blogspot.com/2013/09/alternative-solutions.html)

Model of Solution

This model was created based on the fourth alternate solution as it was chosen to be the best design I had made

Alternative Solutions

Three different tanks have so far been designed based on my current knowledge of what horseshoe crabs need and in what type of environment they thrive in. Each design accomplishes a different goal, and the designs are very basic and undetailed. Whichever design is chosen to move forward with will then be altered to fit with the necessary systems.

The first tank I designed (seen above) was a basic cylindrical tank with an observation window in the front through which the horseshoe crabs could be inspected. I worked in a basic water flow system which ended up not being accurate and was based on very limited knowledge of pumps. This, however, is a small and easily fixable mistake. This tank is good because the cylindrical shape maintains its stability when put under the pressure of many gallons of water. The shape of this tank limits the ability of scientists to evaluate the horseshoe crabs regularly however, because of the depth and radius, the scientists may not be able to easily round up the horseshoe crabs in the tank. If this tank design were to become the final solution, a secondary contraption could then be constructed to make horseshoe crab collection within the tank easier.

This tank was designed with the location of the horseshoe crab breeding ground in mind. Generally the horseshoe crab breeds and lays eggs in the inter-tidal zone, so this design worked in the slope and dry sand area which would be found in the areas in which they live for the first few months of their lives. However, in their youth the dry sand may not be necessary since they generally only leave the water to mate. The shape of the tank, however, allows for tide simulation and better representation of the horseshoe crabs natural environment. One obstacle I am expecting to run into with this tank is the sand. I would like to have the bottom of the tank to be coated in sand from the area, however with the sloped bottom and constant movement of water the sand may settle on the lower part of the slope leaving the top exposed.

The third solution I created was based off of the tanks the NOAA lab already has in place. In the center of the tank is a water drainage pipe which regulates the level of the water. I could then attach this pipe to a water pump and a series of filters to continue using the water rather than wasting resources. I've also worked in the slope which would also be found in the natural habitat and would allow for the crabs to live in slightly deeper water but provides scientists with the shallow water to make accessing the crabs easier.

This last solution was another tank designed off of already existing tanks in the NOAA laboratory, however I modified the style to better fit the needs of the horseshoe crabs. The design of this tank takes into account the natural incline of the shore which the horseshoe crabs would, in nature, live during the time we will be raising them. The design also saves space while also allowing for the necessary scientific observation and separation during their time in the lab. 

Background Information on the Purpose of the Project

Sign in Atlantic Highlands, NJ

Horseshoe crab harvesting has become a common practice to collect the valuable blue blood and also to use as bait for other marine life. The animals are also threatened by habitat destruction caused by climate change. As a result, the population of Limulus polyphemus is declining and quickly becoming a threatened species. With hopes of helping the species thrive, my team along with two other teams has taken on the challenge of creating a simulated habitat for the horseshoe crab. We took this opportunity to expand the population of this very important animal while also presenting the scientific community with the opportunity to study and hopefully better understand the species.

Banking Blue Blood

Production of LAL

Stranded Horseshoe Crabs

Dead Horseshoe Crab in Myrtle Beach

The horseshoe crab is a vital part of the world economy and plays an important role in the medical field as well as in the scientific community. If the population of horseshoe crabs continues to decline, the effects will be felt by everyone including other species of animals. The species is extremely important in the medical community for the special properties of the blue blood the animals produce. Groups like the American Littoral Society and the ERDG are working toward educating the public about the horseshoe crab and also have started programs and campaigns, which highlight horseshoe crab conservation. These groups as well as interested scientists may take the design of our system and apply the design to their needs, whether that is for research or to aid in raising horseshoe crabs to supplement the natural population.

The loggerhead sea turtle has suffered
from reduced numbers of horseshoe crabs

Horseshoe crabs may help with
the development of antibiotics

The red knot bird relies on
the horseshoe crab for food

The horseshoe crab is an ancient
species beginning to die

Just Flip 'Em Program Art Contest Winner

This is a species that has been on Earth for a lot longer than humans have been. Since humans arrived and started changing the ecology of the Earth, habitats and weather patterns are changing and the horseshoe crab cannot keep up. Between over harvesting and habitat loss, their numbers are dwindling and once they are gone they can never come back. Without the horseshoe crab the medical field will lose out on numerous breakthroughs, which could result in furthering the study of horseshoe crabs. If this project works as intended, the scientific community will better understand a species which at the moment is somewhat of an enigma to humans. 

The number of horseshoe crabs is declining

Horseshoe Crab eggs are
very small and vulnerable

Loss of habitat and breeding grounds
threaten the horseshoe crab

Even naturally, horseshoe crabs
find themselves in odd situations

The time has come for the horseshoe crabs to fight back

Overall in this project I hope to provide the scientific and engineering community with the best possible way to go about raising young horseshoe crabs. More than just the marine world will benefit from this project and many people will be effected during the process of creating, finalizing, and utilizing this tank. 




At one year old the horseshoe crab
is about the size of a quarter

In a proper environment, young
horseshoe crabs can thrive

Maintaining a professional mindset is important

Current laboratory tanks

The natural habitat of the horseshoe crab will be mimicked

My team is taking this project seriously and we hope to convey that into our design. The design needs to be sterile for a lab and highly functional and efficient. Wasted space or time is unacceptable and may eventually be harmful to the study. Function comes first in our project, and though I want to make the tank aesthetically pleasing, the project will not fail because of appearance. The tank will end up being very similar to a fish tank, though altered to fit the needs of the specific species of invertebrate while also working to please the needs of those who will use the tank to study the species. This tank will mainly be a combination of technologies already created for other uses and will combine to best recreate the habitat of the horseshoe crab. Many of the pieces which will be incorporated into the design can be found in an average fish tank, though we will be altering some and connecting them to perform functions, which will mimic nature.

Design Brief, Specifications, and Limitations of Designing the Tank

Design Brief: Design, model, develop, and build a simulated habitat housing for future MAST students to house 100 horseshoe crabs from 6 months to 1 year in a climate controlled lab setting and have a survival rate of 20% while also allowing for scientific research to expand human knowledge of the species.

Specifications:

• have space to raise 100 six month to one year old horseshoe crabs (five cubic feet)
• increase the survival rates of horseshoe crabs to 20%
• be beneficial to the study and understanding of the horseshoe crab as a species
• replicate the natural environment of the horseshoe crab by simulating natural nutrients, temperature, and features
• be stable enough to not collapse or leak under the pressure of the water in the tank
• properly connect with the pump and nutrient systems
• have a constant flow of salt water
• be waterproof
• run constantly as an entire system
• be replicateable for others to use

Limitations:

• variability of the size of young horseshoe crabs
• availability of space in the lab
• not all natural processes such as inclement weather can be replicated in a lab setting
• joints and seems are weak points
• ability to filter the water within the system to reuse water instead of constant replacing 
• over filtration causing an imbalance of nutrients
• availability of non-corroding materials (ie: plastic, glass)
• the length of the average human arm (limits depth and width of tank)
• availability of generators for power outages
• design simplicity

Research and Brainstorming

The Atlantic Horseshoe Crab (Limulus polyphemus)

• adult females may lay ~90,000 eggs a year
• about 10 reach adulthood
• eggs hatch in the sand and the babies swim for about a week and then settle to walk on the shore floor
• juveniles generally spend first and second summers in intertidal flats
• the species is on the road to being endangered
• at six months they are appx. the size of a nickel
• by one year they reach about the size of a quarter
• live alone the Atlantic coast of the United States
• Chesapeake Bay
• Sandy Hook, NJ
• sexual maturity is not reached until 9-12 years
• they have a higher survival rate in captivity when the tank contains sand compared to without

additional information at:
http://www.horseshoecrab.org/info/lifecycle.html
http://www.ceoe.udel.edu/horseshoecrab/history/lifestages.html
http://marinebio.org/species.asp?id=281
http://iobis.org/mapper/?taxon=Limulus%20polyphemus

Marking Period 1 Calendar of Work and Due Dates

Due Dates:

9/13 - calendar of dates due

9/16 - background information, design brief, specs, limits, summer research/brainstorming, alternative solutions

9/20 - first log due

9/23 - rationale report, model

9/27 - testing procedure, weekly log

10/4 - weekly log

10/11 - weekly log

10/18 - weekly log

10/25 - weekly log, developmental work

10/30 - outline for formal presentation

10/31 - presentations begin

Day after presentation - mentor contacts

2 days after presentation - presentation reflection

Working Plan*:

9/13 - finish formatting blog; look over summer work and items due Monday; visit the NOAA lab to learn what technologies they already have in place; finalize calendar

9/14 - delineate specs and limits; create alternate solution based on trip to NOAA; work on background information
9/16 - finalize tank design; begin modeling the tank structure

9/17 - preparation for informal presentation; continue modeling tank structure

9/18 - informal presentation; update blog

9/19 - begin rationale report; begin adding details and connections for Rob's system additions

9/20 - finish model of tank and add Rob's pump and systems

9/23 - research tank materials; update blog

9/24 - find possible weak points of the tank and add supports into the design

9/25 - begin formal drawings of the tank design

9/26 - explain the weeks work in a log; post testing procedure on blog

9/27 - begin looking at requirements for developmental work
9/30 - begin developmental work

10/1 - update mentor contacts; research materials to be used in connecting the systems to the tank

10/2 - continue working on developmental work and formal drawing of design

10/3 - explain the weeks work in a log; update blog

10/4 - collaborate with other horseshoe crab tank groups to see which direction they are working in

10/7 - finish formal drawings
10/8 - continue research on the needs of young horseshoe crabs

10/9 - look into the average cost of materials to be used in design

10/10 - explain the weeks work in a log; update blog

10/11 - update mentor contacts; work on developmental work

10/15 - make sure systems properly connect with tank

10/17 - explain the weeks work in a log; update blog

10/18 - continue developmental work

10/23 - finish developmental work

10/24 - explain the weeks work in a log; update blog

10/25 - begin to outline formal presentation

10/28 - work on permal presentation and ensure everything needed for a presentation is available

10/30 - update mentor contacts

10/31 - formal presentations; update blog

*subject to change

Works Cited

Babin, Perry. "Working With Acrylic." N.p., n.d. Web. 25 Nov. 2013.

Funch, Peter. Stranded Horseshoe Crabs. 2011. Xray-mag.com. Web. 14 Sept 2013.

Gerhard, Dale. Juvenile Horseshoe Crab Crawls in a Tank. 17 August 2012. Wildnewjersey.tv. Web. 28 Sept 2013.

Gonzalez, Mike. Loggerhead Sea Turtle. 2007. Geargia Aquarium. Atlanta, Georgia. Wikipedia.com. Web. 15 Sept 2013.

Habitats of Horseshoe Crabs. 2013. Afcd.gov.hk. Web. 17 Sept 2013.

Hill, Randall. Dead Horseshoe Crab. 2002. Myrtle Beach. Postandcourier.com. Web. 14 Sept 2013.

Horseshoe Crab Harvest for LAL Production. N.d. Nerrs.noaa.gov. Web. 14 Sept 2013.

Horseshoe Crab Landings. N.d. Dnr.state.md.us. Web. 28 Sept 2013.

Kathy. Baby Horseshoe Crab. 4 October 2010. Flickr.com. Web. 28 Sept 2013.

Lauderdale, David. Flipped horseshoe crabs. 2010. Islandpacket.com. Web. 15 Sept 2013.

Matt. Horseshoe Crab Character. 30 May 2010. Mattoonart.blogspot.com. Web. 28 Sept 2013.

Red Knot. 2005. WVTF.org. Web. 15 Sept 2013.

Reynolds, Joe. Atlantic Highlands Sign. 2007. Bayshorewatershed.org. Web. 14 Sept 2013.

Smilowitz. Just Flip 'Em Program. 2006. Horseshoecrab.org. Web. 14 Sept 2013.

Switek, Brian. Horseshoe Crab. 2008. Delaware. Wired.com. Web. 15 Sept 2013.

              

Thiessen, Mark. Banking Blue Blood. 2011. Nationalgeographic.Com. Web. 14 Sept 2013.

Winter, Steve. Horseshoe Crab eggs. Allposters.com. Web. 15 Sept 2013.