Many fishes are delicious. Grocery stores sell a variety of fresh, frozen and canned fish as well as derivative products such as Omega-3. Once exotic and rare in the U.S., sushi containing raw and cooked fishes is practically a fast food. The selections made possible by international trade and cultural exchange are remarkable. But there's a tradeoff - gains come at the expense of wild fishes whose numbers are dwindling. Even farmed fishes take their toll on wild stocks because there is no truly free lunch in biological systems.
Changes at the grocery store - consumer choice or shortage of fish? It varies by species. That consumer response to concerns about fishes such as Swordfish and Chilean Seabass could made a difference at the fish counter is promising. Instead of wild fishes, we consume more farmed fishes, giving us hope about the possible, but these are isolated successes. The larger problem of avoiding depletion of many fish stocks remains. But what's the right thing to do? We need to eat something, fishermen need jobs, and we only have so much time and money. Choosing to act wisely requires information about specific populations of fishes and making priorities.
Not long ago - before the beginning of the 90's, fish counters stocked lots of halibut, swordfish and cod. As tastes and the reach of global commercial fishing expanded, fishes such as Orange Roughy, Thresher Shark and Chilean Seabass appeared in local supermarkets. Today these fishes are less common and in there place, we find more farmed species such as Atlantic salmon, tilapia, catfish, and new arrivals like basa and swai which are both catfishes from Asia.
The dwindling catch - Although not the same as counting fishes where they live, variations in year-to-year catch can track population variations. Populations can vary for natural reasons that are part of the normal life cycles of certain fishes, or in response to naturally-occuring climate cycles such as El Niño. Populations of sardines are naturally cyclic.
But for fishes such as Orange Roughy and Thresher Sharks, overfishing may be the primary cause of the dwindling catch. Fishing to near depletion has been a recurring theme, affecting fishes that were once common such as Atlantic Cod. Managment of fisheries and allocation of a sustainable catch involves international coordination because many marine fishes swim through many waters. Recent tagging programs reveal that fishes like Bluefin Tuna and Great White Sharks travel thousands of miles over annual and multiyear migrations. Since fish don't recognize protected areas, protecting them in one place but not the other wouldn't work.
PERSONAL CONTEXT
Has the fish selection at the grocery store changed noticeably over time?
What is the most fished commercial fish in the world?
How many fish can we harvest without eroding next year's catch? Making that determination is a fishery mangers task. Which fish are so few that their numbers are too low to sustain current rates of fishing? Which fish reproduce faster?
To decide what's most important, we need basic information about fishes That information includes how many fishes there are, how fast they reproduce, and what they need to survive. We've tried to find useful information where you can start to find answers to these questions.
Whether individual anglers, aquarists, recreational divers, gourmets, citizen scientists, or nature-lovers; or groups representing commercial fisheries, grocery stores, restaurants, resorts, governments and conservation groups, and whether we belong to more than one group, we all need the fishes to be there.
Highlighted on this page -
The unfamiliar fishes we consume and utilize.
How much we fish and how it's changed over time.
The growth in farm-raised fishes.
Polluting the fish we eat.
Native and non-native species in local streams and rivers.
What we catch may surprise you. Tuna and sardines don't top the list. The top spot belongs to a type of anchovy called the Anchoveta (Engraulis ringens). Anchoveta are abundant in the coastal area near Peru where an oceanographic process called upwelling delivers rich nutrient to surface waters. Because upwelling varies with the El Niño cycle, the fortunes of the Peruvian Achnoveta fishery do too.
What are we doing with all that Anchoveta? It goes into processed fish meal used to fertilize farmed plants and feed livestock that includes farmed and ranched fishes. Fish meal contains high-quality protein. Anchoveta are also the source of oil such as Omega-3 sold as nutritional supplements.
Biology basics - it takes food to grow food. Fishes such as the anchoveta and menhaden are consumed indirectly in other foods we eat. Since bigger fishes and animals are dependent on smaller fishes, what we remove affects other marine life. In many case, what we harvest isn't wasted. The scales of menhaden produce the sparkle in cosmetics and paints, and the guts (offal) of fishes is used to manufacture livestock feeds.
Balancing the fish account - Without knowing how much you have and how much you get paid each paycheck, you don't know how much you can spend without eventually going broke. It's the same for fishes but figuring out how many fishes there are, and how fast they reproduce compared with how fast we fish them takes a lot of effort.
Fishes are difficult to see and count in the wild.
They can hide, concentrate in one place, live in many places, experience radical natural cycles of boom and bust, and swim thousands of miles across the ocean, beyond the waters of any single nation. Scientists with an inclination to merge science and engineering devise ways to see and count fishes with diverse lifestyles.
So who counts? Many different groups including governmental and non-governmental groups. Although it's an indirect count, commercial catches can be useful indicators of the abundances of some fishes. On a global scale, the Food and Agriculture Organization (FAO) of the United Nations collects information from contributing nations and produces a report. In the U.S. ...
The human element
The consequences of acting on inaccurate information can be poor.
In the case of global fisheries, over-reported catches made it seem that there were more fish than there really were and allowed fishing at unsustainable rates.
• A Future Without Fish?
World's commercial fisheries must reverse course or face extinction
Joshua S. Reichert, San Francisco Chronicle
Marine biologists observe fish populations to find out things such as how fast they reproduce. They find out everything about how and where they live. Because this is such a difficult task, much is still unknown. Seemingly easy observations such as whether whale sharks lay eggs or give birth to live young and how many at a time are recent observations (Joung et al., 1996).
With population and reproductive rate information in hand, fisheries managers can decide how many fishes can be sustainably caught each year. Sustainable catches are intended to leave enough fish so that there will be enough fish to catch in future years.
Marine Capture Fisheries Production: Top Ten Species in 2006 & 2004 (Worldwide) - FAO Status
Marketed canned or fresh including sashimi grade. Popular sportfish.
Ranking and catch taken from The State of World Fisheries and Aquaculture (SOFIA) produced by the Food and Agriculture Orgranization (FAO) of the United Nations.
Why don't we show more recent data? Organizations like FAO need time to collect and analyze the quality of data that gets packaged into usable reports. That takes time. Thus large datasets such as this (and more familiar reports like the Census) usually report conditions a year or two into the past. It is relatively recent that it has been possible to summarize comparable numbers from many different countries.
SOFIA reports.
With nature being unpredictable and more people to feed, humans have begun to farm and ranch fish in a big way. Some fishes are cultured in tanks on land. Some are raised in natural bodies of water. Others are "ranched" in the open ocean, in large pens where fish food is delivered to them.
Like farming plants, fish farming increases the concentration of fishes on the farm and increases the efficiency of production over natural limits. Although we need efficiency to feed everyone, it comes at some cost to overall resources and other living things. There does not seem to a free lunch.
"Prepackaged" foods, i.e living things, sustain life, except for a special class of living things that can make their own food by photosynthesis.
Through the process of photosynthesis, the energy for nearly all living things on Earth is initially captured from sunlight and packaged into the chemical bonds of molecules that make up plants and algae. Everyone up the food web that eats the animal that ate the photosynthesizer at the base relies on energy from the Sun to stay alive. The energy content that animals derive from food is essential for life, not just the material content. When we eat sugar, it's not so much the carbon molecules in our bodies that we need to replace each day, but the energy we derive from metabolizing or breaking down that sugar that fuels body processes.
All animals can only get energy from "prepackaged" foods, i.e other living things.
Photosynthesizers in the sea include less well-known microscopic bacteria, diatoms and coccolithophores that are as important as grass on land to land animals.
What is photosynthesis?
Animals can't use the energy in sunlight to make food like plants. That's why they eat other living things that have already converted the energy in sunlight into glucose and other organic molecules.
As one animal eats a plant of animal, the Sun's energy is carried up the food web. Animals could not live without plants and other photosynthesizers to conduct the initial step of converting sunlight to energy trapped within chemical compounds like glucose.
TO THINK ABOUT
What wild land animal is equivalent in rank to the wild Bluefin Tuna on a biomass pyramid?
Photosynthesizers make up the first step of a conceptual structure called the "biomass pyramid." That structure shows the order in which energy and materials get passed from the base of the food web up a food chain. The pyramid shape illustrates the quanity of food that is needed to support the next step up. For a fish such as the Meditteranean Bluefin Tuna, or any animal high on the pyramid, there must be an entire pyramid load of food available in its habitat. That principle applies to farmed and ranched fishes too. So growing Bluefin Tuna costs much more in feed than growing Pilchards and in the wild, there is less tonnage of Tuna than Pilchard. Thus the lowly Anchoveta is fished in great quantity from the sea to make our food.
Slated for Phase II.
Look for this section in the future.
Topics include continental shelves, coral reefs, polar seas.
World's most productive fishing groundsThese areas "are confined to major hotspots, less than 10% of the World oceans. The maps shows annual catch (tonnes per km2) for the World's oceans. Notice the strong geographic concurrence of continental shelves, upwelling and primary productivity and the amount of fish caught by fisheries."
Map of the surface elevation and bathymetry of the Earth.90% of all marine fish species (44% of all fish species) live around land, either above or on the continental shelf or in reefs around oceanic islands.Image reproduced from the GEBCO world map, http://www.gebco.net/.
Worldwide biological productivity
Map of global primary productivity.Since life depends on activity at the base of the food web, places where primary productivity is high are the places that sustain the most productive fisheries.Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE. Now public domain.
Exclusive Economic Zones
Map of the U.S. Exclusive Economic Zone.Each coastal nation has an Exclusive Economic Zone that extends beyond land into adjacent waters. The EEZ is important in fisheries, petroleum resources, passage and access to the sea. Managing fishes that move across these boundaries and resolving conflicts involves international law.NOAA
Related: Law of the Sea: EEZ
Tuna sandwich
Depending on whether you buy light tuna or albacore, you may be eating yellowfin or albacore tuna.
For those who love the albacore but not its higher price, there is some consolation. Yellowfin in the "light" tuna usually contains less methylmercury. Methylmercury is an environmental pollutant that gets concentrated in long-lived fishes that are higher up in the food web. Even fishes that live in the open ocean like the swordifishes have elevated levels of this toxin.
High enough to be a concern? the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) are advising women who may become pregnant, pregnant women, nursing mothers, and young children to avoid some types of fish and eat fish and shellfish that are lower in mercury.
Although it's hard to describe, there's another basic taste that humans recognize in addition to the standard sweet, salt, bitter and sour. The fifth taste is unami and the chemical components that impart umami to food are glutamate, inosinate and guanylate. The polarizing taste of anchovies is full of umami that seems more pleasant when its concealed in a caesar salad dressing or worcestershire sauce. Many other popular fish-based foods are also rich in umami and drive our interest in eating these fishes.
Slated for Phase II.
Look for this section in the future.
Whether using rod and reel at a pier, in the surf, on a deep-sea charter, freshwater fishing, or using a spear of your bare hands, fishing is a recreational activity enjoyed by many.
Common CarpCyprinus carpioThis fish was caught and safely released by an 11-year angler from southern California. Photographer - Wayne Boon. Image courtesy of American Carp Society
Click on image to see slide show about fish meal.
