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Red King Crabs

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Stomach evacuation experiment The experiment was designed to estimate the stomach evacuation rate of capelin eggs in red king crabs at an ambient temperature of 2.9°C, which is within the range of bottom temperature at capelin spawning sites along the coast of northern Norway (Sætre & Gjøsæter 1975). The experiment ran between March 27 and April 6 2011. The collection of experimental animals and capelin eggs is described in Mikkelsen (2013). To obtain at least one datum per hour of digestion time, 36 crabs were expected to be sufficient for this experiment. Red king crabs were captured using traps in Porsangerfjord, Finnmark County, Norway (70⁰ 22’ N, 25⁰ 27’ E) in spring 2011. All captured females were released, because females are not allowed …show more content…

In 2006, 25 crab trawl hauls of approximately 16 min duration were conducted, covering on average 5.7 x 10-3 km2 (CV: 0.54). The abundance of crabs (ind. km-2) was estimated for each haul by dividing the number of crabs caught per crab trawl haul by the area covered by the individual haul (Table S1). Estimates of mean abundance (ind. km-2) in each stratum were calculated from abundance values of all crab trawl stations within the stratum (Table …show more content…

km-2) and ED was tested by calculating correlation coefficients (rs). ED was estimated from grab samples taken at the midpoint of each crab trawl track. The correlation between crab abundance and distance from CSA to the midpoint of trawl track was also tested. Finally, distance from CSA was divided into 2 km bins (0 - 2, 2 - 4, 4 - 6, and > 6 km) to investigate whether RKC abundance changed non-monotonically with distance, and the Kruskal-Wallis test was used to examine whether RKC abundance differed between bins. Stomach evacuation model An exponential decay model was fitted to the experimental data on the proportion of eggs remaining in the stomach f(t) at the time (t) after the start of feeding and is given by: f(t)=e^((-b∙t) )

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Using the 0.1 M stock solutions of sugar, a 0.01 M dilution was created for each sugar type by adding water to the stock solution 9 out of 1. A 20 mL dilution was made for each trial. The same volume of each solution (10 mL -5 mL ) was added to the green sponges to create four group; Group 1: Sponge with 10 Ml 0.01 M glucose solution, Group 2: Sponge with 10 mL 0.01 M fructose solution, Group 3: Sponge with 10mL 0.01 M sucrose solution, Group 4 (Control): Sponge with 10 mL water. The four sponges were placed every 90 degrees on the edge of the arena. The isopods were placed into their environment for one to two minutes to acclimate with the environment.

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The experiment consisted of two sub-experiments that when synthesized together, successfully answered our main question. The first of the two sub-experiments focused on collecting data for the creation of a life table in which Daphnia magna were not in the presence of a predator such as Lepomis macrochirus, known in laymen’s terms as bluegill fish. The second of the two sub-experiments focused on collecting data for the creation of a life table as well, but this time the daphnia were subjected to an environment where bluegill fish were present. The collection of the data for the creation of the first lifetable without predation consisted of fourteen replicates or daphnia starting at age 3 and ending at varying ages depending on the mortality of each replicate group.

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By creating experimental beach scenarios, negative and standard, Karpanty, et al, increased and decreased the amount of surface eggs to compare the availability and sufficiency to refuel Red Knots in the Delaware Bay area. They were able to determine that horseshoe crab eggs were sufficient and that Red Knots were not excluded when aggressive shorebirds also foraged on the experimental beach areas. The feeding times were mainly during the day and until high tide. It was observed that Red Knots foraged in high-density areas and along the wrack line, where horseshoe crab eggs were visible and easily accessible. Once that area was depleted, the Red Knots would move on to other horseshoe crab nesting areas.

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Horseshoe crabs, marine arthropods known for their horseshoe like shells have been roaming the Earth long before the dinosaurs. These living fossils only inhabit the Eastern Shore and can be found on Delaware beaches such as the Delaware Bay, but these living relics may be in for extinction. Due to this exact reason Delaware has begun studying and protecting these species. Horseshoe crabs are vital to the Delaware Bay ecosystem,

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723 Words | 3 Pages

The effects of where these larvae are laid can dictate the fate of these gall fly larvae. A study shows that avian predators can assess a gall 's content prior to pecking it open, preferring galls that are inhabited by gall fly larvae. Bird predation was found to be concentrated near the places with a lot of tree cover where S. gigantean a large centipede tends to pray few attacks occurred in the open where golden rods are prevalent. The study was a field experiment to observe the preference of avian predators on galls in different habitat types and that had different sizes, and heights of galls. It is possible that birds have either learned through experience or evolved through natural selection to choose the more profitable galls (Poff et al. 2002).

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The feeding rates on the native blue muscle were compared, it was found that the Asian shore crabs had significantly higher feeding rates on the larger muscle classes, implying that they have a larger per capita impact on the prey population than the green crabs did (6). Although Asian shore crabs are known to primarily rely on plant material, they prefer mussels and other crustaceans, and have been known to deplete them. Even after a decrease in prey availability they are still able to maintain high densities. Evidence supports that when depletion of the preferred food source occurs the crabs turn to cannibalism because it is the best option energetically (7). This allows them to support high densities even when the preferred food source is gone or

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Tradeoffs are a frequent occurrence in Nature. They describe the compromise between two optimal but frequently incompatible traits for an organism. Andrea Pomeroy and her team applied this concept of tradeoffs to the western sandpipers, Calidris mauri, of British Columbia Canada, with the trade off of their ability to forage for food against the costs of potential predation. The main idea examined by Pomeroy was to study the spatial usage (The measure of how intensely a site is used for foraging by the sandpipers) at Boundary Bay, to determine how the birds chose their stop over sites during migration based on the tradeoffs between food abundance and predation risks.

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As you may know, blue crabs help support the fisheries in the Chesapeake Bay. However, over-harvesting has taken a toll on the population. Over-harvesting is most affecting the female species of blue crabs. According to the Chesapeake Bay Program, in

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2000 Words | 8 Pages

As we progress through the course, a complex yet clearer picture is forming regarding how impacts as a result of changes to environmental systems extend well beyond impacts to the wildlife that inhabit those systems. It has become increasingly apparent that environmental changes influence social and economic dynamics as well. The visibility of environmental issues affecting consumers and wildlife alike is very present when we examine estuaries, also know as bays, sounds, or lagoons. Estuaries are mixtures of freshwater and seawater and are created within the indentations found along coastlines. All along the coast of California, where I reside, there are several bays to be found.

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However, underneath the charm of the Alaskan king crab industry lies the dirty grit of a dying planet; go big or go home, American fisheries has nearly exhausted the population of Alaskan king crab vulnerable to serial depletion. Alaskan king crab is the at the pinnacle of demand and the industry is simply responding to the lifestyle demands of their consumers; the ecological footprint of the average American is 9.0 global hectares (23 acres) – the size of 17½ American football fields; moreover, expressing that Americans as a whole require 1.4 earths to retain the tier of their current

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The Chesapeake Bay Oyster Restoration Project aims to help locate a healthy habitat for oysters. The Chesapeake Bay has been affected by the long-lasting drought in Maryland, which influenced the water quality. The drought increased the salinity of the water which has a negative impact on the oysters. According to the National Oceanic and Atmospheric Administration, “the native oyster is an extremely resilient species, able to tolerate wide variations in salinity and temperature—but it has not been immune to the pressures of disease, overharvesting, and pollution in the Chesapeake Bay. As a result, native oyster populations in Chesapeake Bay are at less than 1% of historic levels” (A,& Blue Water Media).

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The abdomen in female, or tail flap, is much broader than in the male crab. This broad tail flap allows accommodate and protect the very large number of eggs till hatching. In both male and female, the tip of the last segment of the tail flap is rounded. At the age of 4 to 5 years, the crab may weigh between 1 to 1.5

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233 Words | 1 Pages

Bristol Bay is located in southwest Alaska and is 40,000 square miles. Within Bristol Bay there are 5 national parks and wildlife refuges. There are 7500 people who live in the area, 66% of them are Alaskan native. Like many Alaskan native communities, they rely greatly on their natural resources around them. Bristol Bay is very remote therefore there are no connecting roads to Alaska’s main cities so the only way to get there is by plane.

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1628 Words | 7 Pages

The crabs are well-suited to hold the small anemones, while the crabs are still functioning. “The anemone is held in place by small ‘teeth’ on the crab's claw which grip it [the anemone] firmly…. This relationship must be a very longstanding one in evolutionary terms, as the original function of the claw was to break up food and put it into the mouth. Such tasks are now

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Pat McGurrin October 24, 2015 Period #1 Honors Biology Mr. Dinunzio Murder and Meal Lab Analysis Procedure: 1.) Gather all materials: Safety goggles, 250ml beaker, water, hot-plate, test-tubes, paper bag tear, stomach contents, pipette, Biruet solution, Benedict’s solution, and Iodine solution. 2.) Put on safety glasses.

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