Marine Mammal Bycatch Research Papers

I believe that underwater noise has an effect on marine animals such as whales. Using information from the passages I will prove my point. Their numbers are declining rapidly and I believe that underwater noise has some involvement in the rapid decrease in their population numbers. The information given within the two passages will help prove my point.

Overfishing is a death sentence to the world’s oceans. As technology continues to improve a great deal of fish can be caught quicker; but at what cost? The effects of overfishing can lead to the extinction of not just the animals being fished, but also the predators that rely on fish to eat. Ninety percent of the ocean’s largest animals have been wiped out due to overfishing (“Overfishing- A Global Disaster”, 2011). National Geographic cites the academic journal Science (2006) that predicts by 2048, all fisheries will collapse due to lack of ocean wildlife. Fish are not the only animal caught in the nets used by fishing vessels. Often animals such as dolphins, sharks, turtles, and seabirds are

Humans fish to survive and in doing so they will target specific species leading to overfishing. Sound pollution is causing issues with the wildlife of the ocean in how they communicate and move around. With human interaction comes trash which gets left in the ocean and affects many different species.

Cetacean bycatch in fishing industries has been a highly debated topic for decades and is still considered an ongoing problem(NOAA 8). However, when it is looked at in comparison, the problem of bycatch has already been solved as much as is possible while still allowing fishing industries to fish at all. Cetaceans are defined as marine mammals. Bycatch is defined as any marine life that is caught and returned to the sea, whether it is dead or alive(Brooke 2). Therefore, many marine animals that are considered bycatch are not harmed in any way. Including these animals, the national bycatch ratio is still low(Brooke 3). Many actions have already been taken since this has become an issue that has reduced bycatch

Cetaceans use sound extensively in both communication, hunting, and navigation. However as humanity continues to make use of the ocean we are constantly filling it with equipment that produces high amounts of sound. These devices are starting to have an impact on cetaceans worldwide, from mass strandings often linked to military exercises to area denials caused by busy commercial shipping lanes and seismic surveys. If consideration is not taken towards this problem now it could develop into something that could have degrading effects on cetacean populations in the future.

In a documentary film directed by Bill Wisenski, “Threatened: The Controversial Struggle of the Southern Sea Otter,” it reveals some of the reasons why the California sea otter population is declining. In addition, it shows the controversy surrounding the “No Otter Zone”. Furthermore, it ensures why the California sea otter population is important to the marine ecosystem. In the film, sea otter populations are endangered because of the significant impact by some human factors. In the 1700’s and 1800’s, fur traders hunted sea otter population to near extinction. Besides this, threatened events such as shipping and drilling oil across the Pacific and along coastal areas; the California sea otters is vulnerable to oil contamination. As a result,

A collection of five samples was made at this site (Table 1). The first sample collection captured 12 Ringed Crayfish with 0 recaptures and 0 that were previously marked. The second sample collection captured 7 Ringed Crayfish with 0 recaptures and 12 previously marked. The third sample collection captured 13 Ringed Crayfish with 0 recaptures and 19 previously marked. The fourth sample collection captured 4 Ringed Crayfish with 1 recapture and 32 previously marked. The fifth sample collection captured 11 Ringed Crayfish with 1 recapture and 35 previously marked. The total number of Ringed Crayfish caught is 47 crayfish with a population estimation (N) of approximately 422 crayfish where N=Σ (CixMi)/ Σ Ri. The total confidence interval of the estimated population (95%CI) is a range from 354.1 to 521.9 for the mark-recapture

Cetacean bycatch in fishing industries has been a highly debated topic for decades and is still considered an ongoing problem(NOAA 8). However, when it is looked at in comparison, the problem of bycatch has already been solved as much as is possible while still allowing fishing industries to fish at all. Bycatch is defined as any marine life that is caught and returned to the sea, whether it is dead or alive(Brooke 2). Therefore, many marine animals that are considered bycatch are not harmed in any way. Including these animals, the national bycatch ratio is still low(Brooke 3). Many actions have already been taken since this has become an issue that has reduced bycatch by an incredibly large amount. In many areas, the amount of bycatch compared to the amount of fish that the fisheries in that area take in is only a small fraction(Brooke 3). There will always be bycatch in fishing, even if a single fisherman is fishing with a single

Sexually mature females can mate year around and are often either pregnant or caring for young throughout their lifetime, and this creates ongoing energy demands that can be energetically exhausting (Chinn et al. 2016). Sea otter mating behavior is aggressive and can further inflict physiological and traumatic stress to females, thereby reducing their foraging efficiency. Other factors such as infections, disease, bio-toxin ingestion and anthropogenic disturbance can also decrease fitness among adult females and increase their vulnerability during reproduction (Chinn et al. 2016). As nearshore inhabitants, southern sea otters often live in close proximity to areas of high human population density in California. These nearshore waterways can be busy with recreational and commercial boating activity that can disturb sea otter populations. Increased disturbance may cause increased stress to the species. Sea otters are of great interest to people who wish to view them, and this is sometimes done up-close by boat or paddle craft. If this activity changes sea otter behavior in any way, it not only violates the Marine Mammal Protection Act, it can also have a negative impact on the species, especially adult females with pups. Additionally, a familiar list of human impacts, such as climate change, overharvest of marine resources, municipal runoff, and habitat degradation likely reduce fitness of marine mammals directly and indirectly. Sea otters can be indicators of the overall health of the nearshore ecosystem (Kreuder et al. 2003). The slow growth rate of the southern sea otter population may be an expression of nearshore ecosystem degradation in California resulting from the fur trade and explosion of human population in

Second, they formed a tight line stage reducing their interpair spacing, and began to undulate their swimming path up and down. During the third stage, spinner dolphins formed a circle surrounding the preys after prey densities increased as to avoid dolphins. Last stage, each pair of dolphins had the opportunity actively fed on the prey for about 10s inside the circle before taking the positions of other pairs. In this study, two response variables can be found which were the whistles rates and echolocation click rates. Both of these response variables were dependent on the foraging patterns as different foraging patterns produced different rates and sound. Besides that, the whistle rates and echolocation rates can also affected by water depth because sound can only detected within scattering layer in this

This paper includes information a particular environmental law. Specifically, the Marine Mammal Protection Act is discussed along with the history and background of this particular environmental law. In addition, the reasoning behind its existence will be elaborately deliberated.

Cetacean bycatch is an ongoing problem in the oceans of the world. Cetaceans are defined as whales, dolphins and porpoises(CBRC 1). Bycatch is “marine mammals that are “captured” but discarded”(Read 2). This happens when fishing industries are fishing for a certain type of marine animal and other marine animals are caught accidentally along with the intended catch. Many times, this leads to the death of the animal that was not meant to be caught, and the animal is tossed back into the ocean. This happens with all kinds of marine life, and it has caused the depletion of many different species. However, this is specifically bad for cetaceans, such as dolphins and whales, because they have such a long lifespan(Brown 2). They also take a very long time to mature(Brown 2). These factors make catching these animals very detrimental to the species as a whole because it takes longer for them to reach an age where they can reproduce(Brown 2). The population of many cetaceans have decreased exponentially. When there is someone watching the nets that cetaceans are accidentally caught in, many times they can be saved. However, there are only select few types of fishing methods that do this, and they are not of the prevalent fishing methods that produce cetacean bycatch. This is a problem because there is a connection between most living animals. If a certain part of the connection is eliminated, it will all fall apart. For example, the relationship between

The constructions of the turbines alone are creating an effect on these mammals because of the frequency of noise that is emitted into the water. These frequencies disrupt mammal communication, location and location of other species around them.

One of the biggest contributions to biodiversity loss is over fishing which is employed by fishery’s. the methods and techniques used include bottom trawling, net, and poisoning in order to catch large sums of fish. Because of these tactics used the biggest problem is Bycatch which are unwanted species that are caught in the nets on accident. To rectify this problem Ward et. Al suggests “Using a single- species approach, the fishing gear is modified to eliminate the harvest of incidentally caught fish species.”(ward et al. 2012). By modifying fishing gear, species like dolphins, sea turtles, and fish would be able to escape the nets and reduce the amount of Bycatch. Through sustainable practices biodiversity loss can be stopped, in a perfect

Bottlenose dolphins find fish by using echolocation. This is when a dolphin sends out a beam of short sonar pulses from its melon, or forehead. The beam reflects off of fish or other objects and echoes back to the lower jaw. The echoes are then sent to the ear bones where they are characterized. Using echolocation, dolphins are able to locate prey that is buried up to one and a half feet under the sand (Cahill 140-141).