Red King Exponential Decay

Hypothesis: High amounts of algae growing in the salt marsh will cause a large decrease in the mud snail population.

This species of communal crab only grows to a width of 1 inch, and has a square purplish body. The main source of food for these creatures are the leaves of marsh cordgrass, and the occasional smaller species of crabs like fiddler crabs. They are also nocturnal creatures, which makes them hard to study. Predators of this species include the Blue Crab, Striped Bass, and certain species of marsh birds.

It shares ancestral background with shrimp and lobsters. They are omnivores with their prey being mussels, fish, plants, and smaller blue crabs (Society). Although the Blue Crab is well established within its ecosystem it is highly sensitive to environmental and habitat changes ("Blue Crab, Maryland State Crustacean", 2016). The detrimental conditions of the Chesapeake Bay have affected the populations of Blue Crabs along with over harvesting.

Horseshoe crabs live in the Delaware Bay and give birth to their offspring there. At this time the red knots, a type of bird, migrate to the area to collect food. The food they collect is the newly conceived horseshoe crab eggs that are buried along the shore sand.

Last Seen With- Populations have declined due to overharvesting, interactions with fisheries, accidentally being caught as bycatch in shrimp trawl nets, on longline hooks and in fishing gillnets, mistakenly swallowing plastic bags floating in the ocean, as well as habitat loss from sea level rise, uncontrolled coastal development, and. vehicle traffic on

The population dynamics of Daphnia magna are observed under three different conditions; low, medium, and high density. The effects of different population densities on the survivorship and reproduction of Daphnia are observed over a two-week period within a lab environment. Over the two week period, the numbers of parent Daphnia alive and dead are recorded daily, along with the amount of offspring produced each day. From the main parameter investigated, the net reproductive rate, the results of the experiment support that higher densities result in less successful reproduction and decreased fecundity. Values for the instantaneous growth rate of the populations also suggests that low and medium density populations allow for

One hypothesis proposes that the reason Steller sea lions have been declining is because of low prey abundance. Animals should use their energy efficiently when they forage to maximize the net amount of energy gained in relation to the amount time and energy that is spent, but it is believed that the reason Steller sea lions are disappearing in such big numbers is because when prey abundance is lower, that Stellar sea lions are less efficient predators (Charnov, 1976). In a recent study conducted on the effect of prey abundance on foraging efficiency, it was found that the less prey that Stellar sea lions had available, the less efficient they were in foraging (Goundie et al., 2015). In the experiment, the researchers took 4 adult Stellar sea lions and had them dive up and down a tube while recording their oxygen consumption, and dive duration. The sea lions dove between the surface of the water and depths of 10 m, and 40 m, and the reason for this was to simulate diving depths of Steller sea lions in the wild (Merrick and Loughlin, 1997). While the sea lions were diving, researchers fed them pieces of fish through two different tubes that were placed away from each other in order to simulate real foraging movements and prey densities. The researchers fed the seals 12 pieces of fish in the

Approximately, two or more weeks after the eggs have been laid, larval horseshoe crabs will emerge from the eggs. These larva then migrate to near shore waters and settle on the sandy bottom of tidal flats where they will further develop for another year or so (National Wildlife Federation 2015). As the horseshoe crab larva develops over these next few years, it will gradually move to deeper water and begin eating food more typical of an adult. Limulus polyphemus will reach reproductive age after about ten years. During these years and those after, horseshoe crabs will molt shedding their exoskeleton allowing them to grow a larger shell for their growing size (National Wildlife Federation 2015). Horseshoe crabs will typically molt 16 or 17 times during their

Trophic cascades are powerful forces that have a pronounced effect on ecosystems. They occur when predation causes shifts in prey dynamics that indirectly lead to enhanced survival in the next lowest trophic level. Walleye fishing bans at Lac la Biche coinciding with a restocking effort have led to a large recovery of walleye populations. The increase in populations of a high trophic level predator should cause shifts in a lower trophic level species (yellow perch) prey preferences from fish towards invertebrate prey. 576 yellow perch stomach collected from 2009 - 2013 by Alberta Environment and Sustainable Resource Development were sent to MacEwan University for processing/analysis. Yellow perch stomachs will be measured (dry weight, empty weight), and prey items will be removed identified and weighed. Sampling procedure differs depending on the type of prey item removed from the stomach (fish, macro and micro invertebrates). Length and weight measurements will be taken for fish and macro invertebrates; whereas, micro invertebrates will be sub sampled until 50-100 individuals can be identified. Data will be analyzed using multi

Shells before 1884, were high-spiraled with thin walls. Compared to the shells found after 1884 were low-spiraled with thick walls. After doing some research, Seeley found that an intertidal crab, Carcinus maenas, had sought after the snails for food.(Seeley) It was found that the shell size had changed due to the harmful

Horseshoe crabs have been on the earth since 30 million years ago which is before the dinosaurs lived. The Delaware Bay has the biggest population of horseshoe crabs in the world. In Delaware, the horseshoe crab population has decreased rapidly which is a problem for the environment. Many shorebirds that migrate, rely on horseshoe crab eggs for food. Also, the biomedical industry depends on horseshoe crabs for the substance, Limulus Amoebocyte Lysate(LAL) that is found in the blood of horseshoe crabs. Finally, fisheries use horseshoe crabs as bait for eels and whelk. Delaware researches and protects horseshoe crabs to benefit the environment and humans.

The Lionfish is considered “one of the most aggressively invasive species on the planet”; there were no enemies within the Atlantic as none of the fish in this area had seen a Lionfish before. They wouldn’t realize that the Lionfish was in fact a cold predator, with extremely effective venomous spines, and had no enemies to limit its own population growth. They reproduce year round and fifty thousand eggs are released on a three day interval from mature females. The warm Gulf Stream aided their cause, as it’s water carried their eggs and larvae North, and

Additionally, the Callinectes sapidus, otherwise known as the blue crab is another native species of the Chesapeake bay. It's decline has been quite evident to the bay and has many effects. With the oysters in the bay, the crab population had been cut by half, from 1980-1990, to 300 million. In 2008, it was reported that the population was declining by 70%. It was quite evident to the researchers that the blue crab population was decreasing due to poor water

Parasitic wasps and flies lay their eggs either in the egg masses or in the larvae of tussock moths (Wickman et al. 1981). Spiders, predaceous insects, and birds also prey upon all life stages of the Douglas-fir tussock moth (Brooks et al. 1978). These parasites and predators are only effective when populations of Douglas-fir tussock moths are low, due to the concept of predator satiation. This concept basically says that predators receive enough food when populations of the prey are high, but hunt their prey more intensively when prey populations are low (Harrison and Wilcox 1995). Harrison and Wilcox (1995) showed this with tussock moths in that outbreaks could be prevented by introducing predators of tussock moths when moth population numbers were

Two crab species, Plagusia and Cyclograpsus, were collected from a local estuary in the littoral and deep water zone for osmoregulation studies. To examine differences in osmoregulatory mechanisms among the species, haemolymph of the specimens was extracted once they were acclimated to varying concentrations of seawater. Using the comparative melting-point, capillary tubes were filled with small samples of seawater and blood then frozen and melted in a -15˚C ethanol bath. The melting time of each was observed thereafter. Subject’s time range fell over 17 minutes of which the majority of the most salinated samples melted