Chapter 15 : Fisheries and Aquaculture

Transcription

1 Chapter 15 : Fisheries and Aquaculture identify the importance of marine ecosystems to Newfoundland and Labrador. Include: Note - oceans and greenhouse gas control : oceans surface (photic zone) abundant in photo-plankton and zooplankton. Photo-plankton absorb greenhouse gas (CO 2). When they die, carry absorbed CO to the ocean floor (aphotic zone), acting as a carbon sink 2 (i) estuaries Areas where rivers meet the coastline. Tidal salt water mixes with fresh. Organisms living here have to handle water level changes. Flushes and disperses pollutants, biodiversity and numbers are an indicator of environmental health (ii) intertidal zone Area between low and high tide water marks. Ex. Salt marshes and swamps, rocky shorelines, beaches (iii) subtidal (littoral) zone Shallow water (<70m), lots of diversity. Currents and tides mix up nutrients, water is warmer than offshore. Light to the bottom. Lots of plant life. Much commercial fishing. (iv) benthic zone (sea bed offshore): continental shelf (CS) Transition between shallow and deep. An extension of the continent ( m) Ex. Grand Banks Map - one of the worlds most productive C.S. areas. Lots of nutrient upwelling. (v) pelagic zone (open water) deep ocean (abyssal zone) Not well understood, but contains a suprising diversity of specialized creatures scavenging and eating ocean snow.

2 Global Fishery - Management describe the present state of the world s fishery in terms of (i) levels of exploitation - 50% of ocean species harvested to the max! 25 % at maximum yield and 25 % overexploited (ii) resource dependence - critical source of food and trade (68 B/yr) especially for poorer countries. Main source of protein for Asia and Africa. 1/4 of worlds catch feeds livestock or farmed fish, produces fish oils. 38M jobs, 150M spin off jobs. Aquaculture is the fastest growing sector (30% of total harvest). list the major issues facing the world s fisheries due to demand from rising global population...climate change, pollution, and habitat loss (512) 1. Amount of / lack of technology impacts the size of harvests (ex. Factory freezer trawlers, sonar, improved / larger nets) 2. OVERFISHING!!!!! To feed fast growing populations 3. Fishing methods impacting habitats / populations (ex. Bottom trawling destroying habitat, bycatch waste, ghost nets) 4. Climate change means water temps and current flow changes, impacting reproduction and migration patterns. 5. Ocean pollution causing bioaccumulation and / or destroying sensitive areas.

3 define fish stock and fish population A collection of populations of breeding individuals of a particular species... but may be separated by geography or NAFO imposed boundaries into smaller fish populations. list the significant events in the history of the cod fishery in Newfoundland and Labrador that have impacted on fish stocks... for 5000 years native peoples depended on the resources of the sea the discovery of Newfoundland by John Cabot in 1497 in 1578 there were over 400 ships taking part in the fishery in the 1950 s factory freezer trawlers were introduced cod stocks begin to decline in the 60 s and 70 s - foreign trawlers fishing in competition with ours - better fish finding technology - no 200 mile limit until 1977 in 1992 the cod moratorium is declared...why? - too many people after too few fish!!!!!!!!! - cod stocks in decline, overestimated by previous science? - increased # of fish processing licenses and operations - cooler water, less growth /reproduction of cod - decline in capelin stocks (cod food) diversification into other species : crab and shrimp are the big makers now money Land & Sea : When the Stages Were Full video describe the role of international agencies in fisheries management. Include: (i) International Commission for the North Atlantic Fisheries (ICNAF) protect the NW Atlantic fish stocks with the best science of the day within a 3 mile limit of shore... rules on fishing mesh sizes, limits, conducting studies, etc. (ii) Northwest Atlantic Fisheries Organization (NAFO) doing the same thing within the new 200 mile limit, working with 11 other countries. New focus is stock recovery planning. describe the role of the Provincial and Federal governments in management of our fisheries Control over fisheries given to Feds after NL joined Canada in DFO is responsible to Min. Of Resources, oversees sustainability and

4 regulations. Provincially, DFA (Dept. Of Fisheries & Aquaculture) oversees licensing, enforcement, and support programs that develop a more sustainable industry. What Role(s) does Science Play in Fishery Management? describe the role of stock assessment in decision making Figures out The size of a fish stock, & compare that to historical size to monitor changes 2. Age and size distribution in a fish stock 3. Recruitment rate of young fish Based on results, recommendations to limits, seasons, or even closure are made to Govt. (Very similar to managing MMAs in Unit 2!) list the two primary sources of information used to estimate fish population and biomass. Include: (i) commercial fisheries Must keep logbooks detailing catch sizes, amount of effort (# hours, nets, hooks, etc), and catches are sampled by fisheries techs to determine age, size, sex, maturity of fish = determines catch per unit effort (ii) scientific surveys DFO / MUN based studies, may involve a sentinel fishery harvest using local fishers describe how the following are used to estimate numbers and biomass of fish: (i) Catch per Unit Effort (CPUE) How much time, gear, and effort is required to land a certain amount of fish. If the CPUE is increasing, that indicated there may be fewer fish. Excellent fishing tech puts fishers right on fish though, so CPUE results may not be dependable by themselves! (ii) hydroacoustics Fish finding sonars tell us about sizes of fish groups, where they are distributed

5 (iii) fish tagging Caught fish that are tagged teach us about growth rate, movements, and help estimate population size (iv) the sentinel fishery Inshore fishers work with scientists to more scientifically set gear as fishing experiments. (Pgs )...helps determine abundance and distribution of cod inshore from year to year. Lab samples are taken, and other fish tagged. define sustainable fishing. Fish stocks must be able to recover from our harvest! We have to fish responsibly, minimizing the fishery s impact on the ocean environment, and on other species. - respect limits / quotas - fishing gear must select only intended sizes of fish - gear catches the intended target species, minimal bycatch - educating fishers through Govt programs and the FFAW list natural and anthropogenic factors that affect the sustainability of marine resources. Include: (i) population status We have to look at effects of fishing on a wider ocean food web...changes in 1 population will have ripple effects on others, which must be carefully regulated and monitored. (ii) biological characteristics of species Understanding how fast a species matures, grows, reproduces, its reproductive success rate, we can better understand how long it would take a population to recover from fishing efforts. (iii) environmental changes Changes in climate and ocean temperatures affect reproduction and migration behaviors of your target species. (iv) fishing pressure Is the species recovering from fishing pressures or not? Fishing pressure has to be regulated to make sure the fish stock is growing sustainably. (v) by-catch, (Accidentally caught species) Gear must be regulated, fishers have to move if by-catch exceeds allowable amounts in 1 place. (vi) habitat loss and destruction Offshore oil production, agricultural runoff, sewage, aquaculture, and fishing techniques (ex. Bottom trawling) can leave long lasting harmful effects on the ocean environment.

6 describe the environmental impacts of : (i) mobile bottom fishing gear Fishing gear lowered to the bottom, then dragged behind a boat...for bottom fish, scallops, clams, etc. They move, bury, rip up features of the ocean floor. Boats are getting bigger, activity getting deeper. Coral habitat ripped up, sediment moved. (ii) ghost fishing Fishing gear lost at sea continues to fish and kill as it drifts or sinks for some period of time. Numbers of nets and their effects are difficult to measure. define by-catch : Accidentally caught marine life and identify the two types of by-catch... commercial species Have extra $ value and add to your income if you catch it accidentally. noncommercial species Seabirds, turtles, marine mammals, and / or species at risk (like wolffish in Unit 1) list the potential environmental impacts of climate change on the fishery: Include: (i) sea ice - is habitat for larger arctic mammals, distribution and numbers affected by shrinking ice area - melting ice changes current circulation and nutrient distribution - loss means more photosynthesis, more open water for some larger mammals, species distribution creeps northward. (ii) ocean temperature - changes in surface temp and current flow, different air masses and different weather patterns created over water (iii) salinity - melting ice dilutes water salinity, changes the rise / fall of currents due to density changes. Ocean currents are expected to change. outline the research steps required to assess the impacts of seals on their prey. Include: (i) determination of energy requirements How much food does it takes to sustain the estimate seal population? Each age group has different needs, so seal population age/size data must be known (ii) where seals feed (and their preferred food sources)

7 Need to understand where seals are distributed through a year, do their travel routes change? (diet variables, pg. 540) (iii) population dynamics of prey species Seals eat a wide variety of food species, so are a major player in the food web. They can stabilize (control) or destabilize other populations in the web because of their diet and behavior. Aquaculture define aquaculture The growing of fish, crustaceans, molluscs, or aquatic plants under somewhat controlled conditions. describe factors that lead to an increased dependence on aquaculture as the primary source of fish proteins. Include: (i) increase demand more human mouths to feed, but ocean resources are already stressed (ii) reduced pressure on wild stocks No need for all of the gear and effort of chasing dwindling fish stocks at sea when you can contain and grow them near home. identify the main species raised in a aquaculture environment in NL Finfish - Atlantic salmon, rainbow trout, arctic char Shellfish - mussels, oysters describe the environmental issues associated with aquaculture operations. Include: (i) impact on wild stocks Aquacultured fish may escape...may compete with wild stocks for food or habitat. Diseases / parasites may transfer between farmed and wild fish. Genetically modified farmed fish MAY possibly breed with wild fish, creating new genetic hybrids. (ii) water pollution Large numbers of concentrated organisms created concentrations of wastes, makes it easier for disease / parasites to spread, and impacts water quality.