Invasive Species In The Oceans

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Invasive Species In The Oceans

• Presented By Bridget Sutton
• April 2005

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Definitions

• Alien Species (non-native, non-indigenous,
  foreign, exotic)
• Refers to a species, subspecies, or lower taxon
  that occurs outside its natural range and
  dispersal potential
• Invasive Species
• An alien species whose establishment and spread
  threatens ecosystems, habitats, or species with
  economic or environmental harm.

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Alien to Invasive

• Fortunately, an alien species do not always
  progress to invasive species
• Very few organisms survive and are able to
  maintain a steady population to the point of
  becoming invasive

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From Alien To Invasive
Many die en route to a new locale
Many die immediately upon arrival by physical and
biotic agents
Naturalization
Lag Phase
Exponential Growth Phase
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The Success of Invaders

• Escape native biotic constraints
• Competitors
• Predators
• Grazers
• Parasites
• There is no control of any kind allows an alien
  species to reach maximum numbers

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Success of Invaders

• Community Vulnerability
• The vacant niche hypothesis suggests that
  communities with small numbers of native species
  cant provide any kind of biological resistance
  to alien species
• Species rich communities are more stable and are
  therefore better suited to fight invasions

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Success of Invaders

• Repeat Offenders
• Some species readily invade many different types
  of environments
• This sparks the question, Do the repeat
  offenders share attributes that significantly
  raise their odds for proliferation in a new
  range?
• Answer still unknown
• Constructing a list of common traits that
  persistent invaders share could aid in attempts
  to predict future invaders

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What is the Origin of Invasive Species?
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Causes of Invasions

• ANTHROPOGENIC
• Invaders spread via human interactions
• Few habitats are free of human influence
• Humans disturb environments where native species
  can not adapt
• This leads to the swift invasion of a
  non-indigenous species.
• Human-modified ecosystems share common traits,
  such as simplified food webs, landscape
  homogenization, and high nutrient and energy
  inputs

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Anthropogenic Causes

• BALLAST WATER
• Ballast water is loaded into un-laden ships to
  ensure stability and balance
• Water is loaded in one port and then released at
  a subsequent port
• The shipping industry is a booming trade
• The vast majority of the worlds commodities are
  transported via ships
• U.S. 79 million tons of foreign ballast water
  are released each year 8 million liters per hour

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BALLAST WATER

• It is estimated that 10,000 or more marine
  organisms may be transported each week
• In Coos Bay, Oregon, 159 cargo ships were sampled
• These vessels contained plankton from 16 animal
  phyla, 3 protist phyla, and 3 plant divisions.
• All major marine trophic groups were represented
  including herbivores, carnivores, omnivores,
  deposit feeders, scavengers, suspension feeders,
  primary producers, and parasites.

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Anthropogenic Causes

• CLIMATE CHANGE
• The Intergovernmental Panel on Climate Control
  has concluded that humans have a profound impact
  on the climate via the burning of fossil fuels
• Burning fossil fuels increasing the amount of
  carbon dioxide in the air and directly
  contributes to the greenhouse effect

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CLIMATE CHANGE

• Climate change ultimately provides new
  opportunities for non-indigenous species
• Produces environmental stress
• Native species may not adapt to the new
  environment of their habitat
• Alien species may find these conditions favorable
  and takeover

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Anthropogenic Causes

• AQUACULTURE
• The business of cultivating marine or freshwater
  fish under controlled conditions
• Globally, aquaculture production has more than
  doubled in the past 10 years and now provides
  about a third of seafood consumption
• Leading to the establishment of many alien
  species
• Often the farmed species is not native to the
  area where they are being farmed.

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AQUACULTURE

• Example The Atlantic Salmon from the eastern USA
  is found in farms from Chile to Norway. If the
  salmon escape, genetic swapping with native
  species will occur.

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AQUACULTURE

• Many species are also bioengineered to provide
  disease resistance and faster growth rates
• If bioengineered species escape, they would
  certainly have an advantage over native species

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Anthropogenic Causes

• TROPICAL FISH TRADE
• There are more than 10 million fish tanks in U.S.
  homes which hold 2 billion ornamental fish of 300
  varieties
• Most of the fish come from breeding farms in
  Florida
• Non-native fish are introduced because they
  escape or are dumped into waterways and sewer
  systems
• Currently, around 100 alien species in Florida
  were released by pet owners or escaped breeding
  farms

Lionfish
Clownfish
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Effects of Invasive Species

• Decreased Biodiversity
• Invasive species wipe out numerous native species
• Invasive species directly eliminate native
  species via predation and grazing effects of
  herbivores
• This leads to an overall loss in biodiversity
• In North America alone, 27 species and 13
  subspecies of native fish became extinct in the
  last century due to the introduction of
  non-indigenous fish

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Effects of Invasive Species

• Economic loss
• Biotic invasions lead to two main categories of
  economic loss
• 1. The loss in potential economic output
• 2. The direct cost of combating invasions
• It took 270 people 1 month and over 2 million
  dollars to eliminate a recent invasion in Darwin,
  Australia of a close relative of the zebra mussel

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Control

• Controlling ballast water exchange is still in
  development
• 1990 U.S. Non-indigenous Aquatic Nuisance
  Prevention and Control Act
• Established a combination of mandatory and
  voluntary programs
• Required or encouraged ships to exchange their
  foreign ballast water far from ports or in water
  where the exchange doesnt pose a threat known
  as open ocean exchange

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Control

• Advantages
• Cost efficient requires no additional equipment
  or training
• Time efficient process is carried out while the
  ship is en route

• Disadvantages
• Difficult to completely remove sediments and
  residual water from the bottom of the tanks
• Organisms stuck to the sides of the tank or
  structural supports will not be readily removed
• During stormy or rough seas it is unsafe

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Control

• Combination of methods effective
• Chemical treatment Using oxidizing and
  non-oxidizing biocides
• Ozone is a promising non-oxidizing agent
• Disinfects water via iodine and hydrobromus acid
  production
• Interaction of ozone and seawater is unstable
• Treatment is non-corrosive
• Kills in excess of 99.9 bacteria in 5 hours
• 90 kill rate of zooplankton ater 10 hours
• 85-90 kill rate of small fish and crabs

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Control

• Biocontrol
• Introduce a predator, competitor, parasite, or
  disease from the invasive species natural
  habitat that will effectively control a pest
  population
• Must be host specific
• Non-target species damage can be high due to
  direct predation and competition for resources

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Control

• Example Chesapeake Bay
• Summer jellyfish reaching high numbers
• Stinging tourist, clog nets, and block water
  pipes
• Introduced amphipods to control the jellyfish
• Summer jellyfish preyed on a comb jelly,
  Mnemiopsis leidyi
• If the comb jelly was released from predation,
  catastrophe could result
• Black Sea in 1982 altered the food chain and
  led to the collapse of fisheries

Mnemiopsis
Summer jellyfish
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Control

• Example Australia
• Daughterless gene is inserted into invasive
  male carp
• Will lack the sex-determination enzyme
• All offspring will be male
• With declining female numbers, the invasive
  species will nose dive
• Zebrafish
• Must not be able to move between species

carp
Zebrafish
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Picture Sources
www.pbs.org/wgbh/nova/ice/greenhouse.html www.erin
.utoronto.ca/.../num/aquaculture.htm www.minokasag
o.org/ www.providence.edu/polisci/students/megapor
t/ballast.htm www.investigacion.izt/uam.mx/ocl/zoo
plankton www.amonline.net www.csiro.au www.slc.ca.
gov