I found the highest number of L. polyphemus in the Main Lagoon, although the difference in the number found in the Main Lagoon and Moon Pond was not statistically significant. The Main Lagoon seems to have favorable environmental conditions for horseshoe crabs, as it is the sub-basin with the largest area for them to inhabit, and it has the deepest water. However, very little information is known about the habitat preferences and requirements of horseshoe crabs. They can tolerate and cope with a wide range of environmental conditions, especially temperature and salinity, and as a result adults are classified as environmental generalists (Sekiguchi & Shuster, 2011). Horseshoe crabs have been encountered in water deeper than 200 meters, but studies …show more content…
polyphemus are sexually dimorphic, with females being larger than males (Brockmann & Smith, 2009). Brockmann and Smith (2009) suggested that the mechanism underlying this is a difference in growth patterns between males and females, whereby males mature at a smaller size (estimated 16 molts), whereas a female matures in 17 molts (Sekiguchi et al. 1998; Brockmann & Smith, 2009). Different populations of horseshoe crabs usually differ in size and in their degree of sexual dimorphism, which may be due to ecological factors such as resource availability, or environmental factors such as temperature (Brockmann & Smith, …show more content…
polyphemus individuals for which I recorded age, 55 were classified as middle-aged (older than 9-11 years). Horseshoe crabs reach sexual maturity and spawn around 9-11 years of age, after which it is believed that they no longer molt, or molt infrequently (Botton & Ropes 1988; James-Pirri et al. 2002; Shuster, 1982). However, very little is known about the lifespan of horseshoe crabs, so there is no way of knowing the specific ages of the individuals in East Harbor. The prosomal width cannot be used to determine age because growth stops in adults, and there are a variety of sizes within each age class (Grady, 2001). A protocol was developed to visually estimate the age based on the appearance of the prosoma; however, this method classifies individuals as young, middle-aged, and old, and does not directly indicate how many years the horseshoe crab has been alive. Results of tagging studies have estimated that after reaching maturity, they live for around 5 to 7 years as adults, for a total life span of 14 to 19 years (Grady,
T. californicus is found from Alaska to Baja in small, shallow tidepools and tidal flats in the upper spray zone where they cannot avoid the full effect of visible and ultraviolet (UV) radiation. Individuals assemble in areas of lower radiation at midday, yet have no preference to the intensity of light at dawn and dusk (Hartline and Macmillan 1995). These tiny arthropods inhabit all types of marine sediments from sand to fine mud and ooze. Along with plankton, T. californicus eats microscopic algae, protists, bacteria, diatoms, algae and microbes (McGroarty 1958). When the concentrations of the species in their habitats are high, T. californicus will turn to cannibalism for a food source. The nautilus eye present in the species is rich with fatty acids and provides a good food source for the animal.
A lobster must shed its shell in order to grow. It takes about five to seven years for a lobster to become a legal size harvestable adult. Soft-shell is the term used for a newly molted lobster. A soft-shell lobster has a shell with room for growth. Soft-shell lobsters are not as full of meat because their new shell is larger than the muscle inside the body. The part not filled with its body’s muscle tissue is filled with water. Soft-shell lobsters may look big on the outside, but they have a much lower meat yield on the inside. Most adult lobsters molt from June to September depending upon location and water temperatures.
The yeti crab is a very recent discovery. Nothing is known about its reproduction habits, due to its place of living.
Zebra mussels have now found there way to the United States originating from the Caspian Sea and sought habitation, originally, in Lake St. Claire when ballast water brought them in. From there, zebra mussels have spread and have caused havoc to the environments and its biodiversity, specifically, Presque Isle. Zebra mussels are filter feeders of zooplankton and phytoplanktons, making the water appear clearer, but not cleaner. They have negatively impacted the existence of clams, walleye and several other organisms. In order to preserve the biodiversity of Presque Isle, zebra mussels must be culled and controlled. Several methods that can be utilized to achieve this goal is by chlorination, poison, scraping, etc.
The location is one of the most critical factors to analyze thoroughly because it helps predict whether the sales of the choosing location will be good or not? Although the Boiling Crab is in the growth stage, it still has to focus on new locations that the owner plan to extend to these areas. As I mentioned in the introduction, the owner plans to open the Boiling Crab in four new locations soon.
If someone is a native of Maryland, they know exactly what one is talking about when the Maryland Blue Crab is brought up into a discussion. In 1989, the Maryland Blue Crab, scientifically known as the Callinectes sapidus Rathbun, was designated the State Crustacean (Blue Crab, Maryland State Crustacean). This crab is not only a key component on the ecological system of the Chesapeake Bay, but also a key economical component of commercial fisheries; although not endangered, the issue of maintaining the population of the species is critical to the Chesapeake Bay and also its inhabitants.
The Chesapeake Bay is the nation’s largest estuary with six major tributaries, the James, the Potomac, the Susquehanna, the Patuxent, the York, and the Rappahannock Rivers, feeding into the bay from various locations in Maryland, Virginia, Pennsylvania, and the District of Columbia (Chemical Contaminants in the Chesapeake Bay – Workshop Discussion 1). These areas depend on the Bay as both an environmental and an economic resource. Throughout the last 15 years the Chesapeake Bay has suffered from elevated levels of pollution. Nitrogen and phosphorous from wastewater treatment plants, farmland, air pollution, and development all lead to reduced water clarity and lowered oxygen levels, which harm fish, crabs, oysters and underwater grasses (Key Commission Issues 1). There are other types of pollution in the bay such as toxic chemicals, but because nutrient pollution is the most significant and most widespread in the Bay its effects are the most harmful to fisheries. Nitrogen and phosphorous fuel algal blooms which cloud the water and block sunlight from reaching underwater grass beds that provide food and habitat for waterfowl, juvenile fish, blue crabs, and other species (Blankenship 11-12). Algae plays a vital role in the food chain by providing food for small fish and oysters. However, when there is an overabundance of algae it dies, sinks to the bottom of the Bay, and decomposes in such a manner that depletes the oxygen levels of the Bay (11). The reduced oxygen levels in the Bay reduce the carrying capacity of the environment and these “dead areas” sometimes kill off species that can not migrate to other areas of the Bay, such as oysters (11). Increased abundance of algal blooms also led to the overabundance of harmful and toxic algae species and microbes such as the microbe Pfiesteria, which was responsible in 1997 for eating fish alive and making dozens of people sick (12). The heightened awareness of diseases that can be contracted through consumption of contaminated fish also has an economic impact. Therefore, the excess levels of nitrogen and phosphorous have fueled an overabundance of algal blooms, which has reduced water clarity and lowered oxygen levels, affecting many species within the bay and ultimately the industries that rely on these species.
The bay's harvest and many of its other attractions bring tourists and in turn revenue for the area. Oysters and blue crab are a big part of the culture in the bay area. However, these organisms are in danger and need help. Description of the problem Eutrophication is a concern in the Chesapeake Bay. Eutrophication is caused by excessive amounts of nutrients.
Organized in the class Actinopterygii, seahorses, Hippocampus spp., are marine dwelling organisms found in bodies of water which span from tropical to temperate zones around the Earth. As cited by Foster in Life History and Ecology of Seahorses, research by R. A. Fritschze suggests that the genus Hippocampus diverged at least 20 million years ago from its ancestral origins. Research pertaining to organisms organized under the genus Hippocampus are conflicting in regards to the number species contained within it, although a general figure places the number at around fifty discovered species(website source). These odd-looking organisms reside at shallow depths of less than 30 meters and can be found in habitats containing seagrass beds and coral reefs(Foster 10). Hippocampus spp. are all predatory organisms, their main sources of food consist of small crustaceans and fish, as well as other organisms which are small enough to be consumed(lourie 10). Although Hippocampus spp. are predatory, their size and restricted mobility capabilities place them at risk of being prey for other carnivorous organisms.
The Artemia franciscana can survive in extreme conditions of salinity, water depth, and temperature (Biology 108 laboratory manual, 2010), but do A. franciscana prefer these conditions or do they simply cope with their surroundings? This experiment explored the extent of the A. franciscanas preference towards three major stimuli: light, temperature, and acidity. A. franciscana are able to endure extreme temperature ranges from 6 ̊ C to 40 ̊ C, however since their optimal temperature for breeding is about room temperature it can be inferred that the A. franciscana will prefer this over other temperatures (Al Dhaheri and Drew, 2003). This is much the same in regards to acidity as Artemia franciscana, in general thrive in saline lakes, can survive pH ranges between 7 and 10 with 8 being ideal for cysts(eggs) to hatch (Al Dhaheri and Drew, 2003). Based on this fact alone the tested A. franciscana should show preference to higher pH levels. In nature A. franciscana feed by scraping food, such as algae, of rocks and can be classified as a bottom feeder; with this said, A. franciscana are usually located in shallow waters. In respect to the preference of light intensity, A. franciscana can be hypothesized to respond to light erratically (Fox, 2001; Al Dhaheri and Drew, 2003). Using these predictions, and the results of the experimentation on the A. franciscana and stimuli, we will be able to determine their preference towards light, temperature, and pH.
World Archaeology, 31:3:329-350. Mitani, J.C. et al 1996 Sexual Dimorphism, the Operational Sex Ratio, and the Intensity of Male Competition in Polygamous Primates. The American Naturalist, 147:6:966-980. Rogers, Alan R. and Arindam Mukherjee 1992 Quantitative Genetics of Sexual Dimorphism in Human Body Size.
Pea crabs, from the family Pinnotheres pisum, are kleptoparasites found around the world's oceans in different Bivalve mollusks species, specifically oysters and mussels. These soft-shell crabs are natural occurring pests, they were not brought or transported by humans around the world but rather evolved to infest mollusk species for food and protection. Their life cycles start at being birthed in areas where oysters or mussels are born in the previous or same year. The timing of the two species is offset to give the mollusks time to grow big enough to hold the crab juvenile. Once inside, the crab sits right next to the feeding filters of the mollusks and eats. If there is enough food being filtered, the mollusk is hardly affected by the presence of the pea crab, but with less food, the mollusk's health starts to decline, though they won't die, because the crab must eat first. The carbs cause damage to the mollusk's gills and the mollusk
...enthic, coral reef, and estuaries. Some freshwater habitats include marches, lakes, rivers, ponds, wetlands, and bogs.
The experiment measured the survival rate, the growth rate, and the size of the brine shrimp at the time harvested in various environments. To obtain these measurements, three environments were created: sea water, brackish water, and freshwater. For this experiment the scientists used 5 liter plastic buckets. Every two days, half of the water from each bucket was discarded and new water, of each respective salinity, was added into each bucket...
Lotze, Heike K., Marta Coll, Anna M. Magera, Christine Ward-Paige, and Laura Airoldi. "Recovery of Marine Animal Populations and Ecosystems." Trends in Ecology & Evolution 26.11 (2011): 595-605. Print.