Fisheries Study Guide Questions-1

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University of Minnesota-Twin Cities *

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1011

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Geography

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Oct 30, 2023

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docx

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Fisheries Study Guide Questions Note : While various additional optional resource links are provided on the Canvas site, the exam will only cover material presented during the video lecture and items you have been directed to review on Canvas. 1. Be familiar with the terminology we discussed. Bioaccumulation & Biomagnification  MN fish eating guidelines Toxic chemicals & heavy metals flow into the ocean from human activities. While many, many of the chemicals settle & the water body & are consumed by organism that live feed on bottom sediments. Because the chemicals aren’t digested. They bio-accumulate w/in organism & become more concentrated as they pass along the food chain. Fish then bio magnify chemicals & their fat, such as arsenic & mercury from organism that they eat. These pollutants may be retained w/in the fish for a long time. As a result, fish eating guidelines frequently recommend eating smaller fish. Eating fewer fish that other fish. In other words, eat smaller fish or eat fish lower on the food chain. True moist skin & fat, & then eat fewer fatty fish. In MN, these are some of the guidelines that we have for people who fish. So larger fish might be one fish per week. For smaller fish, you might be unrestricted in terms of the number of fish that you could eat in a week. World Inland Capture Production  13 countries produced more than 75%  Asia accounts for ~67% of global production  Three major species groups account for more than 75% (carps, tilapias, freshwater crustaceans) 2. What is a fishery? What is aquaculture? Fisheries  Components o Fish o Habitat o Other aquatic organisms o Fishers – people catching or using fish  Fishing – An activity leading to harvesting of fish. It may involved capture of wild fih or rasiing of fish through aquaculture Aquaculture  Breeding, rearing, & harvesting of plants & animals in all types of water environments including ponds, rivers, lakes & the ocean o It’s a form of farming 3. Why are fisheries important? What are the health benefits and risks of eating fish? Importance  Water surface area ~ 71% of Earth

 Food source  Employment Health Benefits of Eating fish  Benefits o High in: o “Good” fats (omega-3 fatty acids) o Long-chain amino acids o Vitamins & minerals  Multiple health benefits 4. How has the production and utilization of fish changed since the period of 1986-1995? How are fish caught in marine and inland fisheries? Marine Fisheries There are varieties, variety of ways in which fish are caught in marine systems.  Midwater trawl  Driftnetting  Demersal (bottom) trawl  Longlining Inland Fisheries  Methods of catching fish o Ice fishing o Using fishing pole o Spearing o Using a sane or dragnet o Using a bow & arrow Production & Utilization  There is an increase in productions, which is only about 2% rate of growth. The rate of growth is really lowered to its level because of the declines in marine fisheries. And that decline largely

was caused by a decline in marine capture of pelagic fish, particularly in entropy beta’s, a reduction in fishing vessels & catch in from world wide events.  So contrast, a relatively small increase of 2%, w/ a larger increase of 301% over that same period of time in aquaculture. So while aquaculture represented only 20% of the total production in 1990s, compared to 49% in 2020. 5. What are technological changes which have helped increase the capture of fish? What is the status of marine fisheries? Marine Technological Advances  Changes (largely marine) o Power o Boat size o Depth o Refrigeration o Echo sounders & sonar o LORAN o Fish aggregating devices (FADs) Most boats are motorized, allows them to grow in size. Assessing Fish Population Status  Catch/unit effort  Capture & recapture  Sampling Assessing fish population is difficult, especially in the marine fishery, because smaller fishing vessels usually aren’t subject to licensing registration requirements. And thus, data from that source is really incomplete. Thus, knowing the exact status of the world’s fisheries is difficult to determine. 6. Be able to compare fish farming vs. farming for beef. Farming Fish vs Beef 7. How is the aquatic food web impacted by overfishing? What is bycatch? Why is it a concern? Environmental Concerns Marine Fisheries  Sustainability/ food web impacts  Bycatch & bottom trawling  Other Aquatic Food Web  When too many fish are taken out of the ocean, it depletes the population of adult fish & doesn’t leave enough fish to reproduce & replenish their dwindling numbers  It also creates an imbalance in the food web, which can lead to the loss of other important marine length o Example: what will happen if we overfish tuna? o Five finfish species account for 24% of the total marine capture & the top 14 species account for 39% of the total marine capture Bycatch & Bottom Trawling Issues

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