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What’s the biggest threat to marine life?

By: Broadreach HQ High School Dive + Sail , Middle School, Scuba Diving, Marine Biology, Wildlife Biology

As the human population grows, the demand for natural resources, such as salt and freshwater fish, increases as well. To keep up with demand, advanced technology is used to find greater numbers of larger fish. Our desire to net the largest species with the biggest individual fish size has resulted in overfishing down the food web. As the numbers of these larger fish populations decrease, we begin to fish smaller species that were not previously sought after. Because of this, overfishing has the most damaging impact on marine life ecosystems than any other danger they face.

Overfishing and the food web 

One of the largest concerns with overfishing is how detrimental it is to the food web and to fish population size. The number of eggs that a female fish can produce is directly related to their mass, meaning that the larger fish produce more eggs than the smaller ones do. If we remove the largest species with overfishing, we eliminate a large percentage of egg layers, which impacts the entire food web dynamic, not just that species. This is due to by-catches, the nonselective fishing method that catches everything instead of just specific targets. All species that are caught in these are killed then discarded. This is a huge waste of life and continues to be a problem despite efforts to reduce by-catching methods. However, humans can help stop overfishing by creating more marine protected areas where fishing is not allowed, and making smarter choices when buying fish for consumption, such as buying local and sustainable fish, and eating small, wild fish rather than large, farmed fish.

Sustainable fishing

Seafood is a major source of protein for the human population, but current fishing practices aren’t sustainable due to their many negative impacts on marine and aquatic life. The big question becomes: how can we continue fishing without destroying the aquatic ecosystem? Much of this will need to be done at the governmental level through regulations and increased monitoring of fishing businesses – however, our communities can help as well by putting an emphasis on “sustenance fishing,” which is fishing designed to provide only what is needed for consumption while deterring large scale fishing operations. Sidenote: it also wouldn’t hurt if humans reduced seafood intake and opted for more sustainable sources of protein.

Government regulations

Another way to help reduce needless loss is to enact catch limits for both companies and individuals. Governments can regulate when, where and how much fish companies can catch. This has had some success, but it can be difficult to effectively enforce these regulations.

In order to protect particular species, regulations have been passed that keep fishermen from catching certain fish year-round and instead limit them to a particular time of year. These seasonal limitations are often structured around spawning, or breeding, seasons, allowing the fish to reproduce and help maintain their population size. Due to some complications, enforcing a minimum catch size is a much more commonly used regulation. This requires a fish to be a certain size in order to be kept for consumption, usually determined by species. This helps to ensure that the fish has reached sexual maturity and has therefore reproduced at least once before being caught.

Farming fish

Another approach to relieving the pressure on wild fish populations is the use of aquaculture, also known as aquafarming. This method involves cultivating aquatic populations under controlled conditions and turns them into a “crop.” While a somewhat controversial method, aquaculture puts less pressure on wild fish and tastes exactly the same.

At this stage in our society, the hunter and gatherer lifestyle is insufficient; with the steadily increasing size of the human population, much of our food is either farmed or produced. Moving forward as a worldwide community, we need to figure out how we can sustainably handle the collection, production and processing of marine life. If we continue things as we have been, our oceans and lakes will be depleted long before we satisfy the human need for fish. Whether it’s through additional fishing regulations or through advancements in aquaculture, policies need to keep up if we want to maintain sustainability.

If you’re interested in learning more about marine ecosystems, fish biology and conservation efforts, check out or high school study abroad adventures.