Killer Whales in Aquatic Biology Dissertation

killer whales. It has 6 sources.

The following is a brief overview of the biological classification, diet, distribution and social behavior of the mammalian orcinus orca. The research also outlines the factors that are responsible for the decline in orcinus orca population around the world today. Special emphasis has been given to resident orcinus orca to demystify the concept that orcas are lethal to the fishermen and hence should be targeted for hunting.

Don't use plagiarized sources. Get Your Custom Essay on
Killer Whales in Aquatic Biology Dissertation
Just from $9/Page
Order Essay

Orcinus orca, commonly known as the killer whale, is a top predator marine mammal. Orcas are very social animals and live in pods. During the past 30 years extensive research has been conducted for the species regarding behavioral ecology, genetics, population monitoring, behavioral studies and acoustic research. Much of that research has been dedicated to the study of resident orcas. In recent years there has been a sharp decline in the numbers of resident orcas. In the following study the author outlines the various issues relating to the cause of the decline have been suggested, some of them are declining fish populations, vessel traffic, toxic exposure and underwater noise. The researcher will also prove the misconception that killer whales are harmless to humans.



Kingdom: Animalia

Phylum: Chordata

Subphylum: Vertebrata

Class: Mammalia

Order: Cetacean (all whales, dolphins and porpoises)

Suborder: Odontoceti (all toothed whales)

Family: Delphinidae (all ocean dolphins)

Genus: Orcinus

Species: orca (“British Columbia Killer Whale Adoption Program” 2004)


After humans, killer whales are the most widely distributed mammals on earth. Although they are found in all oceans, they prefer colder areas especially the polar areas and are most abundant in Antarctica, Northern Japan, Iceland, Norway, Alaska and the Pacific Coast of North America. The largest population is estimated to be 160000 in Antarctica. A lot of researches on orcas have been conducted in the British Columbia and Southeastern Alaska. Two types of orcas are found in these regions the resident and transient. These two vary in terms of morphology, habitat, diet and vocal patterns. The resident orcas are further divided into Northern and Southern clans.

Transients and residents have been located along the western coast of North America from Southeast Alaska to California. Off shore orcas have been encountered far from the coast line from the West Coast of Vancouver Island to Los Angeles.

Structural Details

The killer whale or the ‘wolf of the sea’ is the largest member of the dolphin family Delphinidae. The orcas can be distinguished by their distinct black skin and white patterns and their large dorsal fins. The adult male grows up to 9m (10,000 kg), the female 7m (7,500 kg) while the calf or juvenile is 2.5m (200 kg). The average life expectancy of females is longer than that of the male; 50 to 90 years for females compared to 30 to 60 years for males.(“British Columbia Killer Whale Adoption Program” 2004) The principal difference between the male orca and female orca is the difference in length, weight and structure of the dorsal fin. The dorsal fin of the male is longer and more up right than that of the female which slightly bends backwards. The male dorsal fin can grow up to 2m and the female 1m. It is difficult to determine the sex of the juvenile since the dorsal fin of the calf is very similar to the dorsal fin of the female (Lacey, Hughes and Miller 2000)

The killer whale has a stocky body with lateral tail fins, a rounded head, large flappers or pectoral fins and a sickle shaped triangular dorsal fin. The dorsal fin is more pointed and centrally positioned in a transient killer whale. The vertical movement of the symmetrical tail fins and the pectoral fins can propel a killer whale to a maximum speed of 45 km/hr. The average traveling speed of the killer whale is 6 to 8 km / hr. The high and short burst of speed is very effective during the act of catching prey.

The killer whale has very acute senses of sight and hearing and they respond well to touch. A distinctive white patch is located over the eyes and ears of a killer whale. The large teeth of the killer whale are conical, enameled and interlocking. A maximum of 26 pairs or 52 teeth are present in an adult. To facilitate hunting the teeth are bent inwards and backwards. The blow hole is located near the top of the head. The orcas breathe air at the surface of the water through this nostril and emit a low misty column of water. Killer whales usually stay on the surface of water since they have to breathe air but when they do dive, the blow hole is locked by nasal plugs which are operated with fast acting muscles. The killer whale can dive down up to 100 meters and transient orcas can stay underwater for 5 to 15 minutes whereas the residents can stay below for only 4 minutes.(“The (Orca) Killer Whale” 2004)

For hunting purposes it is necessary for the killer whale to be as camouflaged as possible. Their black upper skin and white lower skin help them to remain inconspicuous. Viewed from above, the black skin blends with water and viewed from below and underwater, the white skin remains indistinguishable from the light surface water.

Diet few decades ago there was a misconception about killer whales, and fishermen used to kill them on sight. The killer whale has never been known to attack humans. It is true that the killer whale is at the top of the food chain in the marine world and its meals include fishes, seals, squids and whales. Resident killer whales mostly feed on fishes like salmon and squids, it has not yet been established that birds are one of their diet items. It is believed that the transient killer whales are more opportunistic hunters feeding on any mammal they can find. (“British Columbia Killer Whale Adoption Program” 2004)Transient killer whales are also more silent and do not involve themselves into much playful activities which actually helps them in hunting and taking the prey by surprise. Transient killer whales usually hunt mammals which have ears. Off shore killer whales feed on schools of fish. (“British Columbia Killer Whale Adoption Program” 2004)These orcas have more nicks and scaring on their fins suggesting that sharks may be included in their diet.

Residents hunt in larger groups or pods whereas the transient killer whales hunt in smaller groups. All the members of the group may cooperate and hunt together. Typically the resident killer whale would emit noises to locate prey, the sound would bounce back from objects or prey and hence the killer whale would be able to locate its prey. This process is known as echolocation. Transient killer whales sometimes play with the pray by slapping it and tossing it in the air. Often the bounty is shared by all members of the group.

Social Behavior

Whales do not have marked territories and belong at any place where they are. The pod is the primary social structure of the killer whale and each orca belongs to a pod for life. These pods develop distinct dialects and vocal noises. This distinct pattern of vocalization helps them determine a member from non-member.

The structure of the pod is matriarchal. A pod is made up of many matrilines in which the females move around with their offspring. The infant calf is nurtured by the mother till the calf reaches adolescence which is usually 15 years. The bond is not broken when the mother dies.

Transient killer whales display a more variable social structure in which the male may leave a pod upon maturity and join another clan or he may hunt as a loner. Transient pods are also smaller (1 to 7) than resident pods (5 to 25) and sometimes two or more resident pods may combine to form super pods of 150 whales. (“The (Orca) Killer Whale” 2004)Killer whales do not migrate seasonally but they do travel long distances with their respective pods in search for food.

Killer Whales exhibit numerous social and playful activities like diving, breaching, spy hopping and tail slaps. They are also kept in large aquariums for circus show and entertainment purposes.


It has been proven that the transient and resident killer whales have no direct lineages and there is also no apparent interbreeding between the two. Similar results are found in the case of northern and southern killer whales. Killer whales do not interbreed within their own pods and matrilines. Mating does occur outside pods. (“British Columbia Killer Whale Adoption Program” 2004)

Issues Affecting the Recent Decline in Orca Numbers

Decline in fish populations

Over fishing and degradation of the fish habitat has decreased the fish populations in oceans. Resident killer whales have been shown to feed mostly on salmon (90%) and now salmon fish are very scarce. (“Issues Affecting the Southern Resident Orcas” 2004)This might compel resident orcas to change their regular patterns of movement in search of food. Another theory indicates that killer whales dive deep down to feed on bottom fish like halibut, rock fish and greenling. The populations of these fishes are just 2% of what they were in the 1950s. (Ylitalo et al. 2000)

Toxic Exposure

PCBs or polychlorinated hydrocarbons via toxic waste dumps, oil spills and industrial and human refuse pollution is the main culprit for the high levels of toxicity in killer whales. Killer whales are predators at the top level of the food chain. Any toxic pollution would accumulate in high levels as we move up the food chain. The pollutants cause tissue contamination and infertility as well as a high probability of epizootic disease. (“Issues Affecting the Southern Resident Orcas” 2004)

Vessel Traffic

High boating activities in coastal areas reduce the breathing space of orcas which is an essential aspect of their habitat. There is a greater probability of collision between a vessel and an orca or on the other hand the orcas would avoid collision and change their routes. (“Issues Affecting the Southern Resident Orcas” 2004). When killer whales surface to breathe they are instead subjected to exhaust fumes of a vessel (Matkin et al. 1997)

Underwater noise

Underwater noise pollution caused by vessel traffic, sonar and various other activities and devices seriously harms the orca habitat.(“Issues Affecting the Southern Resident Orcas” 2004) Orcas depend on echolocation for hunting and traveling, they chirp, click, squeak and whistle in order to communicate with other members of the pod. This vocal environment is disturbed by noise pollution. (Ylitalo et al. 2000)


As a result of all these harmful activities the status of northern residents is ‘threatened’, southern ‘endangered’, transient ‘threatened’ and off shore ‘special concern’. (“British Columbia Killer Whale Adoption Program” 2004)During the last five years resident population has fallen by 4.9%. If all issues are accounted then the estimation for extinction of killer whales is 74 years, 95% confidence interval of 33 to 121 years. (Ylitalo et al. 2000; Taylor & Plater 2000)


Author not available], British Columbia Killer Whale Adoption Program, [Online] 2004 Available at Accessed 4/2/04

Author not available], Issues Affecting the Southern Resident Orcas, The Whale Museum, [Online] 2004 Available at Accessed 4/2/04

Author not available], OMPlace, The (Orca) Killer Whale, Whales in Danger Information Service, [Online] 2004 Available at Accessed 4/2/04

Lacey, RC, Hughes, KA and Miller, PS 2000. Vortex: a stochastic simulation of the extinction process. Chicago Zoological Soc.

Matkin, C.O., D. Schel, G. Ellis, L. Barrett-Lennard, H. Jurk and E. Saulitis. 1998. Comprehensive Killer Whale investigation, Exxon Valdez oil spill restoration project annual report (Restoration Project 97012). North Gulf Oceanic Society, Homer, Alaska.

McCain, B.B., et al. 2000. National Benthic Surveillance Project: Pacific Coast. Organic Chemical Contaminants Cycles I to VII

1984-90). NOAA, Seattle.

A van Ginneken, A, D. Ellifrit and Balcomb K.C. 2000. Official Orca Survey Field Guide. Center for Whale Research, Friday Harbor,


Ylitalo et al. 2000. Contaminants in Killer Whales, The Science of the Total Environment 281-2001 183-203

Taylor and Plater et al. 2001. Population Viability Analysis for the of the Killer Whale, The Center for the Biological Diversity, Tucson, Arizona, July 2001.

Yurk et al., 2002. Cultural transmission within maternal lineages: vocal clans in resident killer whales in southern Alaska, Animal Behavior, 63, 1103-1119.

Get Professional Assignment Help Cheaply

Buy Custom Essay

Are you busy and do not have time to handle your assignment? Are you scared that your paper will not make the grade? Do you have responsibilities that may hinder you from turning in your assignment on time? Are you tired and can barely handle your assignment? Are your grades inconsistent?

Whichever your reason is, it is valid! You can get professional academic help from our service at affordable rates. We have a team of professional academic writers who can handle all your assignments.

Why Choose Our Academic Writing Service?

  • Plagiarism free papers
  • Timely delivery
  • Any deadline
  • Skilled, Experienced Native English Writers
  • Subject-relevant academic writer
  • Adherence to paper instructions
  • Ability to tackle bulk assignments
  • Reasonable prices
  • 24/7 Customer Support
  • Get superb grades consistently

Online Academic Help With Different Subjects


Students barely have time to read. We got you! Have your literature essay or book review written without having the hassle of reading the book. You can get your literature paper custom-written for you by our literature specialists.


Do you struggle with finance? No need to torture yourself if finance is not your cup of tea. You can order your finance paper from our academic writing service and get 100% original work from competent finance experts.

Computer science

Computer science is a tough subject. Fortunately, our computer science experts are up to the match. No need to stress and have sleepless nights. Our academic writers will tackle all your computer science assignments and deliver them on time. Let us handle all your python, java, ruby, JavaScript, php , C+ assignments!


While psychology may be an interesting subject, you may lack sufficient time to handle your assignments. Don’t despair; by using our academic writing service, you can be assured of perfect grades. Moreover, your grades will be consistent.


Engineering is quite a demanding subject. Students face a lot of pressure and barely have enough time to do what they love to do. Our academic writing service got you covered! Our engineering specialists follow the paper instructions and ensure timely delivery of the paper.


In the nursing course, you may have difficulties with literature reviews, annotated bibliographies, critical essays, and other assignments. Our nursing assignment writers will offer you professional nursing paper help at low prices.


Truth be told, sociology papers can be quite exhausting. Our academic writing service relieves you of fatigue, pressure, and stress. You can relax and have peace of mind as our academic writers handle your sociology assignment.


We take pride in having some of the best business writers in the industry. Our business writers have a lot of experience in the field. They are reliable, and you can be assured of a high-grade paper. They are able to handle business papers of any subject, length, deadline, and difficulty!


We boast of having some of the most experienced statistics experts in the industry. Our statistics experts have diverse skills, expertise, and knowledge to handle any kind of assignment. They have access to all kinds of software to get your assignment done.


Writing a law essay may prove to be an insurmountable obstacle, especially when you need to know the peculiarities of the legislative framework. Take advantage of our top-notch law specialists and get superb grades and 100% satisfaction.

What discipline/subjects do you deal in?

We have highlighted some of the most popular subjects we handle above. Those are just a tip of the iceberg. We deal in all academic disciplines since our writers are as diverse. They have been drawn from across all disciplines, and orders are assigned to those writers believed to be the best in the field. In a nutshell, there is no task we cannot handle; all you need to do is place your order with us. As long as your instructions are clear, just trust we shall deliver irrespective of the discipline.

Are your writers competent enough to handle my paper?

Our essay writers are graduates with bachelor's, masters, Ph.D., and doctorate degrees in various subjects. The minimum requirement to be an essay writer with our essay writing service is to have a college degree. All our academic writers have a minimum of two years of academic writing. We have a stringent recruitment process to ensure that we get only the most competent essay writers in the industry. We also ensure that the writers are handsomely compensated for their value. The majority of our writers are native English speakers. As such, the fluency of language and grammar is impeccable.

What if I don’t like the paper?

There is a very low likelihood that you won’t like the paper.

Reasons being:

  • When assigning your order, we match the paper’s discipline with the writer’s field/specialization. Since all our writers are graduates, we match the paper’s subject with the field the writer studied. For instance, if it’s a nursing paper, only a nursing graduate and writer will handle it. Furthermore, all our writers have academic writing experience and top-notch research skills.
  • We have a quality assurance that reviews the paper before it gets to you. As such, we ensure that you get a paper that meets the required standard and will most definitely make the grade.

In the event that you don’t like your paper:

  • The writer will revise the paper up to your pleasing. You have unlimited revisions. You simply need to highlight what specifically you don’t like about the paper, and the writer will make the amendments. The paper will be revised until you are satisfied. Revisions are free of charge
  • We will have a different writer write the paper from scratch.
  • Last resort, if the above does not work, we will refund your money.

Will the professor find out I didn’t write the paper myself?

Not at all. All papers are written from scratch. There is no way your tutor or instructor will realize that you did not write the paper yourself. In fact, we recommend using our assignment help services for consistent results.

What if the paper is plagiarized?

We check all papers for plagiarism before we submit them. We use powerful plagiarism checking software such as SafeAssign, LopesWrite, and Turnitin. We also upload the plagiarism report so that you can review it. We understand that plagiarism is academic suicide. We would not take the risk of submitting plagiarized work and jeopardize your academic journey. Furthermore, we do not sell or use prewritten papers, and each paper is written from scratch.

When will I get my paper?

You determine when you get the paper by setting the deadline when placing the order. All papers are delivered within the deadline. We are well aware that we operate in a time-sensitive industry. As such, we have laid out strategies to ensure that the client receives the paper on time and they never miss the deadline. We understand that papers that are submitted late have some points deducted. We do not want you to miss any points due to late submission. We work on beating deadlines by huge margins in order to ensure that you have ample time to review the paper before you submit it.

Will anyone find out that I used your services?

We have a privacy and confidentiality policy that guides our work. We NEVER share any customer information with third parties. Noone will ever know that you used our assignment help services. It’s only between you and us. We are bound by our policies to protect the customer’s identity and information. All your information, such as your names, phone number, email, order information, and so on, are protected. We have robust security systems that ensure that your data is protected. Hacking our systems is close to impossible, and it has never happened.

How our Assignment Help Service Works

1. Place an order

You fill all the paper instructions in the order form. Make sure you include all the helpful materials so that our academic writers can deliver the perfect paper. It will also help to eliminate unnecessary revisions.

2. Pay for the order

Proceed to pay for the paper so that it can be assigned to one of our expert academic writers. The paper subject is matched with the writer’s area of specialization.

3. Track the progress

You communicate with the writer and know about the progress of the paper. The client can ask the writer for drafts of the paper. The client can upload extra material and include additional instructions from the lecturer. Receive a paper.

4. Download the paper

The paper is sent to your email and uploaded to your personal account. You also get a plagiarism report attached to your paper.

smile and order essay GET A PERFECT SCORE!!! smile and order essay Buy Custom Essay

Place your order
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
The price is based on these factors:
Academic level
Number of pages
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more
Open chat
Need assignment help? You can contact our live agent via WhatsApp using +1 718 717 2861

Feel free to ask questions, clarifications, or discounts available when placing an order.
  +1 718 717 2861           + 44 161 818 7126           [email protected]
  ++1 718 717 2861         [email protected]