Aquaculture
Wild fisheries on the Bay are increasingly being augmented with aquaculture systems to meet the demands for Chesapeake Bay seafood. New technologies are being developed worldwide to farm seafood in a sustainable manner. The unique challenges of designing aquaculture systems for the Bay are presented along with examples of working systems.
0 Aquaculture Overview
Aquaculture refers to the breeding, rearing, and harves ng of plants and animals in all types of water environments including ponds, rivers, lakes, and the ocean.
Aquaculture accounts for 40% of all fish products worldwide. Almost 90% of aquaculture ac vity takes place in Asia. In the U.S., which currently imports 78% of its seafood, aquaculture has seen a 400% increase in past 20 years.
Farm raised seafood is viable because 75% of world wild fisheries are fully or overfished.
However, there is concern about fish that escape into the wild and water quality issues associated with
Conceptual Offshore Sustainable Aquafarm aquaculture. [h p://www.whoi.edu/fileserver.do?id=6798&pt=2&p=9550]
1 Aquaculture Overview
Food and Agriculture Organiza on of the United Na ons
49.8 million tons of finfish in 2014 [www.mdsg.umd.edu/sites/default/files/images/Fish-in-hand.jpg]
16.1 million tons of mollusks in 2014 [www.bbsrc.ac.uk/bbsrc/cache/file/14E1CEDB-E11C-4B2C- B7F62405FE3D8D60.jpg]
6.9 million tons of crustaceans in 2014 [h p://www.freshfromflorida.com/var/ezdemo_site/storage/ images/divisions-offices/aquaculture/agriculture-industry/ World Aquaculture Produc on Volume and Value of Aqua c Animals and aquaculture-products/crustaceans/marine_shrimp_banner/ Plants (1995-2014) [h p://www.fao.org/3/a-i5555e.pdf] 2 1622245-1-eng-US/marine_shrimp_banner_banner.jpg] Aquaculture Overview
Aquaculture species can be produced in marine or freshwater environments using various produc on systems.
Closed systems can incorporate water-recircula on systems that reduce the reliance on large quan es of water to maintain water quality and the health of cultured organisms. Sea cages Racks Marine aquaculture systems include:
• Sea ranching
• Surface lines Subsurface lines • Subsurface lines Surface lines • Racks • Sea cages • Ponds • Hatcheries
[h ps://www.daf.qld.gov.au/fisheries/aquaculture/overview/types]
3 Aquaculture Overview Sea Ranching or Open Aquaculture Systems (ac ve feeding) Open sea-cage aquaculture refers to the rearing of aqua c species, within enclosures in natural waterways. Floa ng mesh cages are anchored to the seafloor and vary in size depending on the scale of opera on and the species cultured. Juvenile stock is sourced either from hatcheries or wild popula ons and grown out in pens un l a marketable size has been reached.
A worker stands on a mobile pla orm on the fish farm's sea cage off Australia’s Geraldton coast (photo by Kathryn Diss) [h p://www.abc.net.au/news/2011-03-01/ the-sea-cage-contains-yellowtail-kingfish/2666510]
[h p://goodfishbadfish.com.au/?page_id=33]
4 Aquaculture Overview S cks, Ropes, Racks and Cages (passive feeding) The culture of numerous shellfish species is carried out in systems open to natural waterways. Larval stages may be collected from the wild or produced in hatcheries. These are then placed into the water column by methods including a achment to s cks or ropes, or containment in racks or cages.
Oyster racks in South Australia [h ps:// adelaidefoodies.com/2014/05/16/world-aquaculture- conference-2014-2-port-lincoln-eyre-peninsula/]
[h p://goodfishbadfish.com.au/?page_id=33]
5 Aquaculture Overview Semi-closed Aquaculture Systems Semi-closed aquaculture refers to the land-based produc on of a species, in which water is exchanged between the farm and a natural waterway. Wastewater is released from the ponds into the local waterway, whilst the farm is replenished with fresh water pumped back into the system.
Land-based aquaculture typically involves digging out large ponds, which are then filled saltwater. The easiest way to fill a pond with is to build it close to the sea. This land is now needed for nursery habitats, flood abatement, nutrient filtering, etc. and other compe ve uses. [h p://www.speakupforblue.com/predator- resistant-aquaculture]
[h p://goodfishbadfish.com.au/?page_id=33]
6 Aquaculture Overview Closed Aquaculture Systems Closed system aquaculture refers to the land-based rearing of aqua c species in raceways, tanks and ponds. Recircula on technology is implemented which cycles water through filtra on processes and returns it back into the aquaculture system. This process aids in maintaining water quality whilst ensuring minimal exchange with natural waterways.
Marine Harvest’s new state-of-the-art recircula ng aquaculture hatchery on Vancouver Island has been stocked with more than a million Atlan c salmon. [h ps://aquaculturedirectory.co.uk/first-fish-enter-marine- harvest-hatchery/]
[h p://goodfishbadfish.com.au/?page_id=33]
7 History of Aquaculture
Large-scale, commercial aquaculture started in the mid-20th century but there are worldwide archeological findings that show aquaculture itself goes back thousands of years. While many cite China as the home of aquaculture, evidence indicates aquaculture started in many areas at various mes.
Australia, 8000 – 6000 BC China, 3500 BC
In China, waters subsiding a er annual river floods le carp The Gunditjmara people engineered channels to bring water and young eels from behind. Shown here is a net enclosure system on Tiam Giang to low lying areas. They created ponds and wetlands linked by channels lagoon (Ariel Lucerna) [h p://2.bp.blogspot.com/-_mrdT5tyxrU/ containing weirs. Woven baskets were placed in the weir to harvest mature eels. VEbPV7nsl0I/AAAAAAAAKJk/J96IDmhBxRw/s1600/ [h p://www.gunditjmirring.com/na onalheritagelis ng] Enclosures_in_Tam_Giang.png] 8 History of Aquaculture
Egypt, 2000 BC Hawaii, 300 – 800
Ancient Egyp ans devised a land-reclama on method s ll in use. During the spring, large ponds are constructed in saline soils and flooded with fresh water for two weeks. The ponds are stocked with fish caught in the sea. Shown is a lapia in an Egyp an frieze. (Nikola Fijan). [h p:// voices.na onalgeographic.com/2013/07/11/sustainable-ancient-aquaculture/] Early Hawaiians farmed fish and crustaceans using various farming techniques including freshwater ponds, brackish water ponds, seawater ponds and shoreline fish traps. [h p:// wesisland.blogspot.com/2010/09/ancient-hawaiian-fish- ponds.html]
9 History of Aquaculture
France, 1750 – 1850 Ohio, 1853
In the mid 1800s, an oyster farm was built in France using collected oyster spawn. As Two Cleveland physicians, Theodatus Garlick and H. A. illustrated above, wild oyster fishing was well Ackley, performed the first successful ar ficial fer liza on established in Europe by the late 1700s. of fish eggs in the United States in 1853. Shown is a New ["L'Encyclpédie" 1771] York hatching house (ca 1879) [h p://www.heartlandscience.org/agrifood/aquac] 10 Oyster Aquaculture Reproduc on and development Oysters are dioecious, with sexes separate; however, they exhibit alternate sexuality.
The sexual cycle begins with spawning which is triggered by water temperature. Spawned eggs are heavier than water and quickly se le to the bo om where they are transported by currents and waves.
A er fer liza on, cell division proceeds rapidly and within hours, the swimming trochophore stage is formed and the oysters are called veliger larvae.
When the veliger develops two eye spots that are on each shell, it is called an eyed- pediveliger. The eye spots aid in selec ng Life cycle of the Eastern oyster, Crassostrea virginica an acceptable loca on for a achment. [h p://aqua.ucdavis.edu/DatabaseRoot/pdf/432FS.pdf]
11 Oyster Aquaculture
Seed Sources The two primary sources of seed oysters are naturally occurring seed and hatchery seed. Collec on of natural spat is accomplished by placing bags of clean oyster shell or other cultch material in the water prior to the forecasted se lement of the planktonic oyster larvae. If the collec on is successful, the spa ed cultch is transferred to a nursery area.
Hatchery produc on includes the condi oning and spawning of adult oysters, se ng the spat and growing the young oysters in nursery tanks. The majority of oyster hatcheries produce either bags of cultched oyster seed or single (cultchless) oyster seed. So-called “eyed” larvae, which are ready to se le onto cultch, can also be acquired from hatcheries. [h ps://wsg.washington.edu/wordpress/wp-content/ An aquaculturist holds a batch of oyster seeds. (Dave Harp) [h p://www.bayjournal.com/images/ uploads/publica ons/Small-Scale-Oyster-Farming.pdf] ar cle_images/large/2014_06_OysterZone.jpg]
12 Oyster Aquaculture
Triploid Diploid Triploid Oysters In 1979, researcher Standish Allen created a new kind of oyster with three sets of chromosomes, making them triploids. Those extra chromosomes helped Allen's oysters grow fat faster. A triploid oyster, with its triple set of chromosomes, was designed to avoid the market drawbacks of tradi onal oysters. h ps://www.washingtonpost.com/lifestyle/food/oyster-vs-oyster/2012/07/31/ gJQA4Us1MX_graphic.html?utm_term=.25f2f99f5471 Nature's oysters are diploids, and they are seldom sold or eaten during the summer months when they're growing gonads to produce sperm and eggs. Triploids are sterile oysters. They usually don't grow gonads and don't bother spawning, le ng them put all their energy year-round into growing meat. [h p://ww2.mdsg.umd.edu/CQ/ V09N2/main2/]
13 Oyster Aquaculture Growing Methods Bo om culture is the most common method of oyster farming because of the low maintenance and simple prepara on requirements. Cultched seed is placed onto beds, then harvested when the oysters reach appropriate size. The best areas for this technique are protected bays or inlets with
firm mud bo oms where currents and waves Bo om oyster cages require only a small buoy on the surface are not excessive. [h p://www.chesapeakebay.net/blog/post/ not_your_grandfathers_oyster_company]
Floa ng culture uses the sub dal bo oms that are leased from the state. In this method, oyster grow-out trays or polyethylene cages may simply be stacked on the floor of a sink float, or the stack may be suspended from a ra or floa ng longline system in the water column. [h ps://wsg.washington.edu/ wordpress/wp-content/uploads/publica ons/ Marine cs uses oyster floats on the Choptank River Small-Scale-Oyster-Farming.pdf] [h p://choptanksweets.com/aquaculture/] 14 Oyster Aquaculture Some advantages and disadvantages associated with bo om and off-bo om oyster culture techniques Bottom Culture Advantages Disadvantages Less labor to maintain and stage seed for stocking grow- Higher percentage of mortality from predators and pests out areas Lower capital and maintenance expenses as no nursery Higher potential for siltation or grow-out structures are required Less labor in moving shell stock to new areas because Spat usually survive only on one side of the mother shell structures are not involved Generally, fewer permits are required for bottom culture Public resistance to many predator control methods than off-bottom culture Usually less negative visual impact at nursery and grow- out sites Off-Bottom Culture Advantages Disadvantages Less impact from predators and pests More public resistance to visual impact of culture structures Significantly less chance for problems resulting from Potential conflict with recreational boating siltation Use of total water column by three-dimensional culture Fouling organisms severely impact some container techniques systems Spat survival on both sides of the mother shell Labor intensive in initial set-up Less expensive equipment required for harvest Capital cost and maintenance of nursery and grow-out structures Conte, F.S., S.C. Harbell and R.L. RaLonde. 1994. Oyster Culture - fundamentals and technology of the West Coast industry. Western Region Aquaculture Center, Seattle, WA. 15
Oyster Aquaculture
Se ng Larvae Larvae are ready to set when they have a well- developed eye spot and are 290 μm or more in length. The large, eyed larvae can be set on a variety of materials, called cultch. Single oysters are good for off-bo om farming and oyster clusters are good for producing a lot of oysters for restora on projects.
Single oysters can be obtained by se ng larvae on microcultch, very smooth and slippery surfaces, or by chemical induc on. Microcultch is usually made of finely ground oyster shell.
Cluster oysters are the result of se ng larvae on large cultch, usually whole oyster shell. [h p://www.aces.edu/dept/fisheries/ educa on/documents/ A typical arrangement for flow-through larval tank (AR = algal reservoir; P = pump; F = flowmeter; D = drain) Oyster_hatchery_techniques.pdf] [h p://www.fao.org/docrep/007/y5720e/y5720e0a.htm] 16 Oyster Aquaculture
Wellers Single oysters are produced by introducing eyed larvae into containers with fine mesh bo oms and a thin layer of microcultch. The containers, called wellers, are immersed in shallow tanks containing treated seawater. Upwelling and downwelling arrangements for feeding eyed larvae [h p://www.fao.org/docrep/007/y5720e/y5720e0b.htm] Containers are configured so that water can flow up through (upwelling) or down through (downwellng) the mesh bo oms by rou ng water through an opening near the top of the container. [h p://www.aces.edu/dept/ fisheries/educa on/documents/ In Japan, Yanmar cultures oyster seedlings in a floa ng ra -type Oyster_hatchery_techniques.pdf] nursery vessel or FLUPSY (Floa ng UPweller SYstem). [h ps://www.yanmar.com/ltc/global/technology/core_excellence/ marine_farm/img/1716 5d01/img_marine_farm_09.jpg] 17 Chesapeake Bay Oyster Industry
Types of Oysters on the Bay Na ve and imported species of oyster have been considered for aquaculture in the Chesapeake Bay. Crassostrea virginica — The Eastern Oyster is na ve to the U.S. where it has been fished and farmed from the North Atlan c down to the Gulf of Mexico. Each adult oyster filters and cleans up to 50 gallons of water per day— gobbling up algae, and removing dirt and nitrogen pollu on. Disease epidemics of MSX and Dermo began devasta ng oyster stocks in Delaware Bay and the southern Chesapeake Bay in the late 1950s, which raised interest in introducing a non-na ve oyster. Crassostrea gigas — the Pacific oyster and the Chinese Suminoe oyster were evaluated for introduc on into the Chesapeake. The Pacific oyster was rejected for use in Maryland in 1932; the Chinese oyster in 2009, ending a long- me interest in using a foreign oyster to replace or supplement the na ve virginica Crassostrea virginica — The Eastern Oyster oyster. [h p://ww2.mdsg.umd.edu/CQ/ [h p://www.fao.org/fishery/culturedspecies/ Crassostrea_virginica/en] V09N2/main2/] 18 Chesapeake Bay Oyster Industry History of Upper Chesapeake Bay Oystering In some years of the late 1800's, the Chesapeake Bay produced nearly 20 million bushels of eastern oysters, about 60% of North America's oyster produc on. Maryland’s oyster industry then had a value of 17% of the total fisheries products of the United States and employed 20% of the people involved in U.S. fisheries. The Maryland oyster fishery was the most extensive and valuable oyster fishery in the world.
Most of Maryland's historical oyster grounds have been maintained as public. These include the Potomac, Patuxent , Chester and Choptank Historical Upper Chesapeake Bay oyster grounds Rivers as well as Tangier Sound. [h p://spo.nwr.noaa.gov/mfr584/mfr5841.pdf] Vast natural beds of oysters apparently were present in them in colonial mes. During a 1608 voyage of explora on, Captain John Smith wrote that the oysters “lay as thick as stones” in the Bay. [h p://spo.nwr.noaa.gov/mfr584/mfr5841.pdf] 19 Chesapeake Bay Oyster Industry
A Chesapeake Bay tonging bugeye with deep-water tongs. The Oyster Wars began with oyster pirates and legal watermen in Maryland and [h p://spo.nwr.noaa.gov/mfr584/mfr5841.pdf] Virginia figh ng over harves ng rights in the Chesapeake Bay. The disputes did not end un l the mid-20th century. Shown is an illustra on from Harper’s Weekly in 1884 showing illegal oyster harves ng including dredging at night. [h p://www.virginiaplaces.org/natural/oysters.html]
20 Chesapeake Bay Oyster Industry
In 1912, this huge mountain of oyster shells adjoined one of the large oyster packing plants in Hampton, VA. [h p://www.nnhs65.com/ oysters/oyster_shells_03_1.jpg]
Reported landings of oysters in Maryland from 1840 to 1980, in millions of bushels with cri cal milestones [h p://ww2.mdsg.umd.edu/store/books/mdoysters/] 21 Chesapeake Bay Oyster Aquaculture
True Chesapeake Choptank Oyster Oyster Company Company
Hoopers Island Oyster Shore Thing Aquaculture Company Shellfish
38° North Oysters Tom's Cove Aquafarms
Tarkill Aquaculture Chesapeake Bay Ventures Oyster Company Shoo ng Point Oyster Company Ballard Fish and Ward Oyster Oyster Company Company Cobb Sta on Oyster Company 22 Chesapeake Bay Oyster Aquaculture
38° North Oysters Ballard Fish and Oyster Company
The Ballard Fish and Oyster Company 38° North is a series of farms along has been producing clams and oysters the banks of Maryland’s Western for more than 115 years at both Shore, the southern-most p of bayside and seaside grounds along the Maryland where the Chesapeake Bay Eastern Shore of Virginia. [h p:// and Potomac River meet. [h p:// www.ballardfish.com/] www.38northoysters.com/]
23 Chesapeake Bay Oyster Aquaculture
Chesapeake Bay Oyster Company Choptank Oyster Company
The Chesapeake Bay Oyster Company grows Parrot Island Oysters in the shadow of Parrot Island near the mouth of The Choptank Oyster Company is located on Virginia’s Rappahannock River where the Choptank River, a tributary of the salinity ranges from 12-18 ppt. [h p:// Chesapeake Bay. They have been growing www.bayoyster.com/oysters.html] their Choptank Sweets oyster since 1999. [h p://choptanksweets.com/]
24 Chesapeake Bay Oyster Aquaculture
Cobb Sta on Oyster Company Hoopers Island Oyster Aquaculture Company
Cobb Sta on Oyster Company oysters spend most of their grow-out in the mouth of The Hoopers Island Oyster Aquaculture Company Occohannock Creek. Once they reach market grows Chesapeake Gold and Holy Grail oysters on size, they are moved to Magothy Bay for a mul ple 5 acre leases located in an area of the sal er taste. They offer Ship Shoals and Pe te Chesapeake Bay known as Tar Bay. They also Beaches oysters. [h p:// produce oyster aquaculture equipment. [h p:// www.broadwateroysters.com/home.html] www.hioac.com/]
25 Chesapeake Bay Oyster Aquaculture
Shoo ng Point Oyster Company Shore Thing Shellfish, LLC
Shoo ng Point Oyster Company is a family farm located on the remote Eastern Shore of Virginia that provides oysters from three Shore Thing Shellfish has offered farmed dis nct local watersheds; Church Creek Corks oysters, aquaculture products and & Bullseye Oysters from the Lower Bayside consulta on services from St. Mary's County and Shoo ng Point Salts from the Atlan c in Maryland since 2011. [h p:// barrier islands. [h p:// www.shorethingshellfish.com/] www.shoo ngpointoysters.com/]
26 Chesapeake Bay Oyster Aquaculture
Tarkill Aquaculture Ventures Tom's Cove Aquafarms
Tom's Cove Aquafarms offers shellfish Tarkill Aquaculture Ventures LLC was harvested from the cool, clear waters found founded in 2008 and is located between around the historic seafood town of East and West Point, by the cut-thru Chincoteague Island, Virginia. [h p:// where Tarkill Creek meets the www.tomscove.net/] Chesapeake Bay. They offer McKinney’s Island and Ropewalk Liberty Oysters. [h p:// www.tarkillaquacultureventures.com/] 27 Chesapeake Bay Oyster Aquaculture
True Chesapeake Oyster Company Ward Oyster Company
Ward Oyster Company has about 10 to 12 million oysters placed in cages near the mouth of the Ware River, The True Chesapeake Oyster Company is located in the town of Ware Neck in located on St. Jerome Creek, just north Gloucester County, Virginia. [h p:// of the mouth of the Potomac River. They www.wardoyster.com/] offer the Skinny Dipper and Huckleberry Oysters [h p://trueoyster.com/] 28 Chesapeake Bay Fish Aquaculture
The Bay’s wild fisheries have been the focus of local economies and cultures for genera ons. However, some entrepreneurs have tried fish aquaculture at various points to supply a growing popula on with food and protect wild stocks.
While finfish aquaculture is not a major industry on the Bay today, growing fish like striped bass in a pond or in cages does have advantages. Farm-raised fish grow faster than wild fish and are easier to harvest. But there are disadvantages, too. An aquaculture business requires large ini al investments and diligent upkeep. Fish grown in In the 1980s, fish aquaculture was tried on the cap vity catch and spread bacterial infec ons Bay because of the decline of the Chesapeake Bay seafood industry, and the growing na onwide quickly, and they can easily deplete the oxygen consump on of seafood. [h p://www.mdsg.umd.edu/sites/default/files/ supplies in a pond or cage. files/FishCultureinMaryland.pdf] [h p://www.mdsg.umd.edu/topics/finfish- aquaculture/finfish-aquaculture]
29 Chesapeake Bay Fish Aquaculture
Hybrid net-pen culture on the scale that is prac ced with salmon sea-pen culture in Maine, Washington and foreign countries, is not legal in the Chesapeake Bay.
With respect to water temperature, striped bass and hybrids require water in the range of 72° to 78° F for op mal growth.
Although an estuarine (salt water) fish, the striped bass and its hybrids do quite well in freshwater ponds. In fact, during preliminary studies conducted in Maryland, fish cultured in cages in freshwater grew and survived only slightly less well than those cultured in brackish water (10-15 parts per thousand salinity). [h p://www.mdsg.umd.edu/sites/default/files/files/Cultureofstripedbass.pdf]
30 Chesapeake Bay Fish Aquaculture
Based on the seaside of Virginia’s Eastern Shore, Bradford Bay Farms is the only recircula ng aquaculture farm in the na on growing sea bass for market.
Jim Williams (foreground) and Yannig Tanguy count 9- month-old black sea bass at Bradford Bay Fish Farm as they move the fish from one tank to the other. (Dave Harp) [h p://www.bayjournal.com/ ar cle/ could_fish_farms_help_take_ pressure_off_wild_stocks]
31 Aquaculture Questions
• What types of marine species can be farmed using aquaculture? • How much of the world’s seafood supply is provided by aquaculture? • What con nent has the world’s largest aquaculture industry? • List a few types of marine aquaculture systems. • What are some of the earliest examples of aquaculture? • What are some problems with farm-raised finfish? • Which oysters grow faster, diploids or triploids? • What is an advantage of raising oysters on the bo om? • What is an advantage of raising oysters on the surface?
32 Bay Challenges
• What types of oysters can be raised on the Chesapeake Bay? • When were oysters first discovered on the Bay? When did peak harvests occur? • Do oysters add impuri es to the Bay or filter them out? • What are some reasons why harvests of na ve oysters are now 1% or less of historical levels? • Do you think the regula on of wild oyster harves ng is necessary to help the industry recover? • Why is it difficult to economically farm raise fish on the Bay?
33