Human Impact on Marine Life

Over Fishing

Marine Biology

Warm Up1. How does fish get from the ocean to your

plate?

2. What do you believe is the safest way to fish in the ocean without harming the ecosystem?

3. Name some types of fishing that you think could be illegal.

4. Do your best to explain/guess what a hammerhead shark looks like.

Sea of CortezHammerhead Sharks

Humbolt Squid

Hammerhead Shark Video (6.03 Minutes)

Use this video to answer the following questions on Hammerhead Sharks:

1.What body of water are we researching?

2.Where do hammerheads typically swim in the ocean?

3.What organisms are prey to hammerhead sharks?

4.How do they help to keep the ecosystem in balance?

5.What are the hammerhead sharks being hunted for?

6.What is the trophic level of hammerhead sharks?

7.Use the process of cellular respiration in order to explain why carbon dioxide gas can be poisonous?

Humbolt Squid Video(6.45 Minutes)

• What is the major problem with declining numbers of hammerhead sharks? What effect does it have on the ecosystem here?

• How many squid live in this area now? • Why has the squid population grown so much?• What makes them such great hunters?• How long to they live?• How big are they?• How fast can they swim?• Explain how the squids are able to light up under water. What is specialized

about their cells?• Why do you think they are called “invertebrates”? (Think about vertebra)

Overfishing EssayUse the triangle to explain how an ecosystem would be effected if Sea Bass were overfished. Make sure to include:

•identify the trophic level each species occupies •explain how these species will be effected if the Sea Bass population decreases.

HSA Public Release Question:The energy pyramid below shows the flow of energy through the organisms in a kelp forest ecosystem in the Pacific Ocean. Use the energy pyramid to answer the following.How would the populations of other organisms in the energy pyramid be affected if the population of sea urchins suddenly decreased?A. Both the kelp and the sheephead populations would increase. B. Both the kelp and the sheephead populations would decrease. C. The kelp population would decrease, and the sheephead population would increase. D. The kelp population would increase, and the sheephead population would decrease.

Overfishing PracticesLOOKING CLOSER AT HOW FISH ARE HUNTED IN THE

OCEAN.

BY-CATCH – ALL THE ANIMALS CAUGHT IN NETS OR ON LINES WHICH ARE UNINTENTIONAL AND ARE USUALLY DEAD AND THROWN OVERBOARD.

Look at the picture.

List as many types of species that you can think of.

Do you think this is a healthy way to fish? Why or why not?

What are Sting Rays prey to?

Use this information to help explain how/why this sting ray was caught.

Hammerhead and Stingray =__________ to __________

Relationship

A True Save!

• http://www.youtube.com/watch?v=4lrKXCqnBSI

OVERFISHING PRACTICESTake Cornell Notes on the following practices

for commercial fishing:

GILL NETS

DRIFT NETS

LONGLINES

PURSE SEINE NETS

TRAWLERS

Drift Nets

Gill Nets

Which of the following is a gill net and which is a drift net? Make a guess!

Drift Net Fishing

Drift net fishing on the high seas beyond the exclusive economic zone of any nation was banned in 1991 by the UN General Assembly because of its potential to harm all fish stocks and marine animals. Fines for drift net fishing are significant. This type of fishing involves the use of a net, up to twenty miles in extent, that is generally anchored to a boat and left to float with the tide. The net is set out at night and pulled in at sunrise, making it difficult for aircraft surveillance to catch them in the act. On average, a drift net vessel can scoop up half a ton of fish per day. This often results in an over harvesting and waste of large populations of non-commercial marine species (by-catch) by its effect of “sweeping the ocean clean”. The by-catch also includes marine mammals and seabirds.

Summarize this paragraph. What is being explained about laws regarding fishing in the open sea?

Drift Nets

Nicknamed "walls of death" these nets are made of a very strong monofilament (single strand) nylon mesh,

and each net is between 8 - 12 meters deep and may be as long as 65 km, although usually between 32 - 40 km. The nets are often put into the sea at night, where they drift with the current, catching and killing anything that gets in their way, like huge underwater spiders' webs.

This method of fishing is extremely wasteful. Not only is an estimated 40% to 50% of each catch lost when the net is hauled in, but uncounted numbers of fish are injured in the net and may escape only to die later. These nets also catch many dolphins, whales, seals,

turtles and seabirds which cannot easily see the almost invisible netting.

Drift Nets

Use the following pictures in order to explain how using nets to fish can be very harmful to the ecosystem and individual species.

Think of a basic ecosystem.Sharks are consider to be ________________ and top __________________.

Use this information to explain how the loss of sharks could harm the ocean ecosystem.

Longline fishing is a technique used to catch fish in open waters, including those who live near the sea floor. A longline includes a main fishing line up to 100 kilometers in length, with secondary lines branching off it, each set with hundreds or thousands of barbed, baited hooks. This technique is used in international waters, as well as waters controlled by the United States, South America, Australia, New Zealand, and southern African countries, and targets fish species such as tuna, swordfish, and Patagonian toothfish.

Long Line Fishing

Trawl Fishing What is wrong with this type of fishing?

Trawl Fishing

Trawl Fishing

There are devices to make fishing safer for all species in the ocean!Look at the picture below… what is happening?The Turtle Excluder Device or TED is a grid of bars with an opening either at the top or the bottom. The grid is fitted into the neck of a shrimp trawl. Small animals like shrimp slip through the bars and are caught in the bag end of the trawl. Large animals such as turtles and sharks, when caught at the mouth of the trawl, strike the grid bars and are ejected through the opening.

Purse Seine Fishing

Orange Roughy Research

• Page 575

• Conduct Research on the Orange Roughy

• Prepare a summary of this article. Make sure that your article includes answers to the 3 questions at the close of the article.

Personal Essay: Commercial Fishing

• What are your thoughts about commercial fishing?

– Explain how their “stance” on commercial fishing.

– If you were in change it, what would you do differently?

• Provide at least one reference to what we’ve covered in class to back up your reasoning (example-watching the video about Humpback Whales made me realize).

Fish Research NOAA’s guide to fish nutrition etc.

http://www.fishwatch.gov/index.htm