Tag Archives: Fishing

Fishing Methods for a Sustainable Future

Raise your hand if you like eating fish! Many of you probably raised your hand as fish is something that tastes delicious and can be very healthy for you. But is the fish that you are eating harvested in a way that’s healthy for the ocean? It’s hard to know for sure. There are many commercial fisheries that gather fish in a sustainable way. However, there are fishing methods that are destructive to the environment and result in lots of bycatch and habitat destruction. Today we are going to talk about some common commercial fishing methods, some that are sustainable and some that are very disruptive to the marine environment.

First off let’s cover what bycatch is. Bycatch is the term for catching a species of marine animal that you were not intending to catch such as a seabird, turtle, shark, or dolphin. There is an estimated 160 to 170 billion pounds of wildlife pulled from the ocean each year. 63 billion of that is bycatch accounting for 40 percent of all wildlife pulled. The scariest part about this statistic is that it is by no means correct, there is no way to estimate the total bycatch numbers in the ocean because most goes undocumented.

Here are 5 major commercial fishing methods being implemented around the world today. We are going to cover them briefly as well as rate the sustainability score of each method 1 being not sustainable whatsoever to 5 being the most sustainable.

  • Gillnetting/ Driftnetting (1): Basically, a massive curtain of net that is suspended using floats or anchored using weights. The netting is essentially invisible so fish swim into the net and get their gills caught (hence the name). Gillnetting is incredibly successful, but also in terms of bycatch as it entangles dolphins, sharks, and sea turtles. The United Nations and many other countries have banned this approach.
  • Trawling (2): Think of a huge net being dragged behind a boat. The boat is hoping to catch large schools of fish within the net and tire them out forcing them into the back of the net. This practice can be done on the bottom of the ocean or in midwater. Bottom trawling for shellfish and flatfish is especially dangerous and results in massive habitat destruction and bycatch. Bottom trawling’s impact can be lessened by limiting trawling areas and midwater trawling by avoiding areas with lots of marine mammal and sea turtle traffic.
  • Longlining (2): Longline fishermen throw out a central line behind the boat that can go on for up to 50 miles. On this central line dangle thousands of smaller hooks that are left dangling in evenly spaced intervals. These hooks are meant to catch large open water fish like swordfish and tuna but as they are left out they attract other fish and birds that unfortunately don’t survive until the hooks are picked out of the water. If you took the 94 fisheries in the Gulf of Mexico and stretched their long lines out the total length would reach from Miami to London. This technique can be made better by sinking hooks deeper and using different hooks to limit bycatch.
  • Purse Seining (2): This huge net is used on schooling fish in the open ocean by surrounding the school, pulling the bottom of the net closed, and dragging it to the surface. This is more sustainable than others because certain schools are targeted and spotted and not randomly dragged about. However, bycatch is present through the sheer size of nets used and the number of fish caught in each haul.
  • Trolling (4): You have probably seen this one along coastlines where a boat has multiple lines being dragged behind a boat. This is a sustainable approach to open water fishing because soon after being caught, fish are brought to the boat and released without as much stress as other methods. This method has very low bycatch levels and is a sustainable approach!


All of these commercial fishing methods result in the bycatch of many important. ocean animals. Some methods I did not mention are target specific, meaning that you fish for exactly what you want and do not result in bycatch, such as cast netting, harpooning, spearfishing, rod and reel, and beach seining. All of these are essentially negating bycatch as you get exactly what you want without affecting the other aspects of the ecosystem.

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If you want to help this issue of bycatch through commercial fishing take a look at the Monterey Bay Aquarium Seafood Watch website to find out which types of species are caught which ways. This can help you choose the right kinds of fish to eat! Or you can do it the old-fashioned way, grab a fishing rod or spear gun and get whatever fish you want…as long as you have a fishing license.



Seafood watch is a registered trademark of the Monterey Bay Aquarium Foundation


What’s Up with Upwelling?

It’s a universal understanding amongst all fishermen (and women!) that there are good fishing days, and most definitely bad fishing days. Sometimes all it takes is being in the right place at the right time or maybe even sporting some good ocean karma. There is, although, some technicality and logic behind it all to ensure the most optimum of catching days. It may be hitting up the right location, using the right bait, or stalking bait-balls offshore all afternoon. But what initially attracts the fish to congregate in these places? The obvious answer is food, which could be from a variety of sources. One of those sources is upwelling.

coastalupwellingUpwelling occurs all throughout the globe and in different natures. Essentially what happens is surface water along coastal shores is being pushed offshore by the influence of steady winds. As this happens, the pushed out surface water is being replaced by bottom water that is being drawn up through a current. This bottom water is cold and high in nutritious goodies. We see this exactly at the equator where trade winds blow from east to west drawing water away from South America and towards Indonesia. Prime fishing spots are located just off the coast of Ecuador and Peru. nutrientupwellingAlternatively along the California coastline, winds blow southward from Alaska towards Baja. Here, coastal waters, with the influence of the earth’s rotation, are instead pushed out 90 degrees from the direction of the wind and travel out into the Pacific. We call this process Ekman Transport where our rotating earth creates a force that drags the wind-induced currents to the right in the northern hemisphere. This is reversed in the southern hemisphere where it would travel to the left of the wind. We don’t see this happen at the equator, although, because the earth is wider and spins faster there. Ultimately, the same result occurs where water is transported away from the coast and cold, nutrient-rich waters from the bottom are moved to the surface.

This transport of nutritious bottom water along the California Coast promotes prime fishing, especially for local fisheries in our area. The next time you go fishing and can’t find that trusty bait ball of yours, stick close to the shore. Also keep in mind how this natural process might change this upcoming year with El Niño. Typically, strong dissipation in coastal upwelling is observed more south around the equator during this type of event, but we may see some changes along the Southern California coast.

Written By: John Cornett

Photo Credits:
Coastal Upwelling – https://www.climate.gov/news-features/features/upwelling-crisis-ocean-acidification
Nutrient Upwelling – http://oceanservice.noaa.gov/facts/upwelling.html

Marine Protected Areas

Just like national parks protect land, Marine Protected Areas (MPAs) preserve underwater ecosystems. As of now, there are more than 6,500 MPAs, protecting about 2% of our oceans. There are different types of MPAs ranging from “Strict Nature Reserve” that allows no resource removal, to “Sustainable use of Natural Resources” where limited resources can be taken. Catalina Island has a whopping nine marine protected areas, both coastal and offshore. Some of them, like the Long Point State Marine Reserve is a strict “no-take” zone. However, the Bird Rock State Marine Reserve allows the removal of certain types of pelagic finfish.

Marine protected areas can benefit both the environment and the fishing economy. Protected species can grow larger, thus reproducing with higher success rate as well as reproducing more often. This means that as fish populate, some of them will venture out of the MPA. These potentially animals can be caught by fishermen in the area, leading to higher numbers caught, and larger animals caught.


We would like to thank you for visiting our blog. Catalina Island Marine Institute is a hands-on marine science program with an emphasis on ocean exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and ocean happenings. This blog has been created by our staff who have at least a Bachelors Degree usually in marine science or related subjects. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science and ocean information. Feel free to leave comments, questions, or share our blog with others. Please visit www.cimi.org for additional information. Happy Reading!