Fish in Danger

How Overfishing Affects Fish Stocks

When fishing occurs the first fish to be captured and killed are usually the largest and more mature fish. Fish take a long time to reach sexual maturity and because of this when the larger and more mature fish are killed it takes a long time for the fish species to replenish. With the amount of fishing vessels that are deployed into our oceans everyday the amount of fish continues to drastically decline.

Decline of Fish Stock

According to the International Union for the Conservation of Nature, approximately five percent (5%) of 1360 bony shore fish species studied in 38 Caribbean islands are threatened.
Overfishing has also placed many of our larger marine predators on the endangered species list. Some of these predators include sharks of various species, blue fin tuna, turtles and rays.

Data in chart from fish stock

Sharks are one of those fish that take a while to reach sexual maturity and who do not reproduce often. Sharks are fished mainly for their fins and fats and oils. A common delicacy in Asia is shark fin soup but in order to acquire these fins, sharks are inhumanely slaughtered. Shark finning is the removal of a shark's fins while it is alive and throwing its live body back into the ocean. This animal then suffers a long and painful death by either being eaten alive by other fish or drowning, due to its lack of mobility and thus lack of oxygenated water being able to pass through its body. According to a study carried out by a group of researches led by Shelley c. Clarke in 2006, between 26 and 73 million sharks are killed each year for their fins. (Shark Finning )

Photo from: bite-back.com

  

Another type of fish that is suffering from overfishing is the beloved, giant blue fin tuna. This species of tuna is used in most if not all sushi restaurants around the world. Blue fin tuna can cost anywhere between $30 to $170+ a pound, making it one of the most expensive fish in the world.(cost of tuna)
The International Scientific Committee for Tuna and Tuna-Like Species in the North Pacific Ocean (ISC) released a statement in 2013 saying that overfishing of this species of fish has caused it to decline by 96.5%. 

Before you leave check out this very informative video on the ever growing decline of fish populations.

 

Video by: Smithsonian Channel

Save Reefs, Save lives!

In my previous blog we discussed what is overfishing ( when fish are killed faster than they can replenish) and its effects. In this blog, we are going to highlight what are destructive fishing practices and their effects on marine life.

 What are destructive fishing practices?
These are methods that result in permanent damage of marine habitats and ecosystems. Also includes the incorrect use of standard fishing techniques.

Some types of destructive fishing practices:

Fig 1:From coral reefs and sustainable management

• Blast fishing- is usually done in areas where fish are plentiful, for example coral reefs, and is done by detonating explosives in the water. This kills or shocks the fish and allows them to float to the surface of the water where they can be easily caught. The technique allows fishermen to get larger yields while exerting less energy. This method is more commonly used in the Philippines and in South East Asia. Examples of explosives used are dynamite and homemade explosives made of kerosene and fertilizer. ( source: environmental issues )
• Cyanide/ Poison fishing - occurs when  a mixture of sodium cyanide is sprayed into the habitat of the organisms. This allows live marine animals to be caught for use in restaurants and aquariums. The use of cyanide results in the loss of zooxanthellae (photosynthetic algae found in coral), which leads to the discoloration of coral or coral bleaching. This is mainly practiced in South East Asia. (Jones, Ross J., Tim Kildea, and Ove Hoegh-Guldberg. "PAM chlorophyll fluorometry: a new in situ technique for stress assessment in scleractinian corals, used to examine the effects of cyanide from cyanide fishing." Marine Pollution Bulletin 38.10 (1999): 864-874.) 
  
• Bottom Trawling - this is the act of releasing a large net into the ocean that is weighed down by heavy weights. The net is then dragged across the ocean floor thus collecting everything in its path. This method is inefficient and highly destructive, because it not only catches the targeted prey but other unwanted marine life, destroys coral and therefore leads to the destruction of marine ecosystems. ( source: destructive fishing )
  Fig 3: Photo of bottom trawling from bloom association

Before you leave, take a look at this very informative video made by two marine biologists, Dr. Andrea Marshall and Daniel Van Duinkerken.

Video from Marine Megafauna Foundation

Tasty But Costly

Tasty but Costly 

What comes to mind when you hear the word fishing? When I hear the word fishing I think about going on a jetty or pier and casting some cheap lines with friends and drinking, eating and talking and not paying attention to the lines that we cast unless we hear the reel spinning. What most of us fail to think about is the large scale fishing industry and the amount of fishermen that work in our oceans daily. Do you know that approximately 1.2 billion people eat fish on a daily? That fish yields have decreased dramatically over the last 50 years? Or that marine scientist have estimated that our oceans are going to run out of fish by the year 2060? Probably not. The amount of fish that we eat every year has increased since the early 2000s due to more people consuming only fish and vegetables on a daily. Although this maybe healthier for us it has been costly on our oceans.

What is overfishing?

Overfishing occurs when the rate of fishing is inversely proportional to the rate at which fish replenish their species, that is, the rate at which we catch fish is higher than that at which they are able to breed and reach maturity. The rate of overfishing has increased dramatically and in return fisherman yields have been steadily declining.

Impact of overfishing:

1. Changes in the ecosystem
2. Loss of food source
3. Loss of income
4. Extinction of species of fish
5. Destruction of coral reefs

Fig2: Overfishing Model by Greenpeace

With this bit of information in mind I think that we can all come together to help our oceans and stop overfishing, because after we all we need them more than they need us.
Check out this cool and informative video before you leave.

Video by: OCEAN2012EU

Welcome!

Welcome to my blog!

Hey! I am Jaswa Dowrich, an 18 year old first year student at the University of the West Indies St. Augustine Campus, studying Environmental Science and Sustainable Technology and this is my blog.

I aim to make this blog a very informative and interactive platform, where we can share our views, opinions and facts about overfishing and destructive fishing practices whether it is here in Trinidad and Tobago, other Caribbean islands or any other part of the world.

Check out this article by David Biellohttps://www.scientificamerican.com/article/overfishing-could-take-se/ 

I hope you enjoy,

J.Dowrich.