Impact of Anthropogenic intervention on Fisheries Biodiversity 502.docx
1. ASSIGNMENT ON:
Impact of Anthropogenic intervention on Fisheries
Biodiversity
Course No- FRM 502 (2+1)
Course Title -Fish Biodiversity and Conservation Biology
Submitted to :
Dr. C.P Singh
Submitted by:
Abhishek Singh
F-10354/18/22
M.F.Sc (Fisheries Resource Management)
College Of Fisheries Science
Acharya Narendra Deva University Of Agriculture And
Technology KumarganJ Ayodhya U.P .224229
2. Impact of Anthropogenic intervention on Fisheries
Biodiversity:-
Introduction:-
Fish and shellfish for human and animal consumption are taken through
harvest of natural stocks, harvest of “ranched” (released) stocks, and a variety
of aquaculture activities. All of these types of fishing activities affect the
environment and, for most, the term “responsible fisheries” implies efforts to
ensure that the environmental interactions and consequences of fishing
activities are brought into or kept within levels deemed acceptable by current
standards of society. Thus, there are both natural science (identification of
environmental effects of fisheries) and social science (quantification of the
acceptable social norms) components to the consideration of “responsible
fisheries.
Responsible fisheries should, then, include “responsible (i.e. socially
acceptable) care or conservation” of the stocks to be fished. Thus, the
influence on fish stocks of anthropogenically induced changes in the state of
the environment is an obvious and important consideration when developing a
strategy for carrying out “responsible fisheries.
Land use changes and their impacts on fisheries:-
The largest and therefore economically most important commercial
fisheries in the world are marine. The oceans also extend over large
regions of the earth and are characterized by large water volumes and
rapid water circulation. This means that the footprint of human activities
on the environment will be relatively easily eroded in marine
environments. Thus, marine regions and the most important world
fisheries will be the last of the aquatic ecosystems to be obviously
affected by human activities. Nevertheless, there is now evidence from
many coastal and semi enclosed sea areas that changes in land use
practices are influencing the state of the marine environment and,
potentially, fisheries . This realization has put the consideration of
anthropogenically-induced changes in the environment on the global
3. agenda. However, examples of the influence of land use change on fish
and fisheries in freshwater systems are plentiful and well documented.
Loss of or changes in fish stocks resulting from human activities have
been documented in thousands of lakes and rivers (Maitland, 1995). In
considering the potential influence of human activities on marine
fisheries, much can be learned from the historical experience in
freshwater systems.
Farming activities lead to the runoff of nutrients and pesticides to
adjacent water bodies. This nutrient enrichment can lead to
eutrophication. In freshwater systems, this phenomenon has been well
studied and it is now realized that eutrophication is also occurring in
many coastal marine areas (see Jorgensen and Richardson, 1996). In its
mildest form, it affects fish and fisheries by changing the availability and
type of food for the fishes. In some cases, mild eutrophication may
increase food availability for food-limited fish stocks and actually
increase the fish available for harvest by the fishery (e.g. Nielsen and
Richardson, 1996).
Introduction of non-indigenous species: impact on
fisheries:-
Non-indigenous species can be introduced intentionally (i.e. with the
intent of developing a new fishery) or non-intentionally (with ballast
water; through bio fouling of ship hulls, etc.; the building of canals; or in
association with organisms migrating or actively transferred between
different regions). Most non-indigenous species do not survive when
introduced to a new environment. However, there are numerous
examples of introductions that have had unexpected and dramatic
consequences on fisheries.
Impact on fisheries of conservation measures:-
Changes in the relative abundance of organisms in the various tropic
levels of the marine food web will, clearly, influence the function of the
web. In recent years, large predators that feed on fish such as marine
mammals and birds have been the objects of considerable conservation
4. interest. Protection measures have been taken in the EU, for example,
with respect to whales, seals and many marine birds. In a number of
cases, these protection measures have been highly successful and the
previously diminished or endangered stocks of top predators are now
thriving. Examples are some seal populations in the Baltic, and
cormorants along the Baltic and Kattegat coasts. As these large
predators often feed exclusively on fish, an increase in population size
will certainly imply a greater predation pressure on fish stocks affected
by these predators. The magnitude of the increased predation pressure
on fish stocks due to increased predator abundance has not been
determined.
However, some – especially coastal fishermen working, for example, in
areas in close proximity to large cormorant colonies – are convinced that
the competition for fish resources between these large predators and
fishers is intense. Thus, for these fishers, at least, the conservation of
species at the higher tropic levels of marine food webs represents an
anthropogenically-induced environmental effect on fisheries.
Direct Fisheries Effects:-
The extraction of large numbers of wild organisms (e.g., of finfish, sea urchins,
seaweeds, shrimp, and scallops) from marine habitats through commercial
fishing may be the most important impact of any current fishing activity. Cod
and haddock (NOAA, 1992), Atlantic blue fin tuna (Safina, 1993), and many
other fish populations of economic importance to the U.S. (Norse, 1993) have
experienced dramatic declines due to overfishing. Both commercial and sport
fisheries have intensively removed large populations of other edible, bait,
aquarium, and curio trade organisms (such as mussels, abalones, limpets,
clams, tropical seashells and corals, and polychaete worms) from coastal
habitats. Little noticed when first surveyed by the present generation of
scientists, most coral reefs were poised on the edge of profound change from
overfishing of large predaceous and herbivorous fish.
Indirect Fisheries Effects:-
5. Three of the major indirect impacts of fisheries are by-catch—that is, capture
and mortality of non target species (NOAA, 1992)—habitat destruction
(discussed below, under "Alterations in Physical Habitat"), and ancillary
impacts on interacting species or ecosystem effects. In the eastern tropical
Pacific, tuna purse seine fisheries began in the late 1950s and incidentally
encircled dolphins to capture the yellow fin tuna schools typically found
underneath them. High mortality rates ensued for the dolphins, and
populations declined by the mid-1970s to near 20 percent of the 1959
population estimate for eastern spinner dolphin and below 50 percent for the
offshore spotted dolphin (T.D. Smith, 1983). Public concern about this by-catch
was in part responsible for the passage of the Marine Mammal Protection Act.
"Ghost fishing" (lost and abandoned nets that continue to capture fish and
mammals) may have localized impacts.
Exotic Species:-
Introduction:-
Introduction of exotic species has the extinction of native species in aquatic
ecosystems. Major concerns over the introduction of exotic fish are prolific
breeding, predation or competition of introduced species affecting indigenous
biodiversity. While much of the recent attention has been mainly focused on
the adverse impact of exotic species introduction.
Exotic Fishes Transplanted in India:-
1) Game fishes:-
Brown trout- Salmo trutta fario(1863-1900)
Rainbow trout -Salmo gairdner (1907)
Atlantic salmon- Salmo salar (1968)
2) Food fishes:-
Tilapia- Oreochromis mossambicus (1952)
Common carp- Cyprinus carpio (1957)
6. Grass carp - Ctenopahryngodon idella (1957)
3) Ornamentsal fishes:-
Live bearers (27 species)
Egg layers (261 species)
Impact on biodiversity :-
1) Genetic impacts:-
The genetic impact can be classified into two categories.
A. Reduction of effective population size by the ecological, biological &
genetic of introduction.
B. Alteration/extinction of gene pools of the species/crossbreeding or
hybridization & backcrossing.
Extinction due to hybridization:-
Hybridization between exotics & Native species has not only brought in genetic
contamination but even resulted in species extinction in some cases.
Loss of traits:-
It's leading to economic value decline takes place in uncontrolled hybridization
between exotic and native species. Hybridization between bighead carp
(Aristichthys mobiles) and silver carp (Hypophthalmichthys molitrix) should
beneficial properties in terms of growth, food conversion and disease
resistances.
But in further uncontrolled hybridization of these fishes in later generation, the
offspring lost the acquired beneficial traits.
2) Ecological impacts:-
Competition of exotic fishes with the native species for living space with same
niche preference for food with fishes of similar types of feeding habits,
7. predation on native fishes, spreading parasites and pathogens, thereby are
some common ecological concerns.
Predation-Prey Interaction:-
Top carnivorous are often viewed as the most important significant threat as
introduced fishes. Predation directly reduces the size of the prey species in the
ecosystem.
Competition:-
Competition can occur between exotic and native species for food, habitat,
mates and other essential resources. In recent days reported for inland water
bodies, Tilapia Mozambique is considered to be a threat to native diversity.
3) Disease impact:-
The spread of pathogen along with species transported or traded in
aquaculture is a serious concern with several international agencies such as,
FAO, WHO, WTO and OIE.
4) Habitat impact:-
Many species of freshwater animals greatly modify aquatic habitat when
placed into new areas. For eg. Crayfish, common carp, grass carp etc.
5) Socio-economic impact:-
Since the exotic fishes never fetch a higher price than native varieties and also
the decline of the native fish population is observed in the presence of exotic
species in natural waters, the total economic returns declined for the
stakeholders of the capture fisheries. In aquaculture, however, it provided
immediate gain, in most cases without consideration of the long term
ecological consequences.
Construction of shore protection walls::-
Types of Coastal Protection Structures:-
8. 1. Seawalls:-
This large coastal protection structures can be built using different types of
construction materials such as rubble mound, granite masonry, or reinforced
concrete. Seawalls are commonly built and run along shoreline to prevent
coastal structures and areas from the detrimental influence of ocean wave
actions and flooding which are driven by storms. There are various
arrangements or configurations that might be employed includes curved face
seawall, stepped face seawall, rubble mound seawall.
Curved face seawall:-
Curved face seawall is designed to withstand high wave action effects.
Foundation materials loss, which might be caused by scouring waves and/or
leaching from over topping water or storm drainage underneath the wall, is
avoided by employing sheet pile cut off wall. Moreover, the toe of the curved
face seawall is built from large stones to decrease scouring.
Seawall with Curved Face Configuration
2. Bulkheads:-
Bulkheads can be constructed by concrete, steel, or timber. There two major
types which are gravity structures and anchored sheet pile walls. The
bulkheads might not have exposed to substantially strong wave actions and its
main purpose is to retain earth but scouring at the base of the structure should
be considered by the designer. Cellular sheet pile bulkheads are employed for
9. situations where rock is close to the surface and enough penetration cannot be
achieved for the anchored bulkhead type. Moreover, sheet pile should be
sufficiently reinforced for bending moment, soil conditions,hydrostatic
pressures, and support points.
3.Breakwaters:-
There are three major types of breakwaters namely: offshore, shore-
connected, and rubble mound. Not only are they used to protect shore area,
anchorage, harbor from wave actions but also to create secure environment
for mooring, operating, and handling ships.
Micro hydral power stations:-
Between 2010 and 2040 energy demand is expected to increase by 56%
worldwide
1. particularly, oil demand which is estimated to increase in countries, such as
Brazil, China and India
2. This is mainly due to the world’s population unprecedented growth rate.
According to the United Nations, by 2050, the world population will reach nine
billion.
3. Fossil fuel combustion is currently the main source of energy production.
[4]. Anthropogenic greenhouse gas emissions are linked to climate change and
human health problems
[5]. Each year, more than 30 billion tons of carbon dioxide (CO2) are released
into the atmosphere
[6], and around 65% of the world’s excess mortality—The number of deaths
caused by a specific condition or exposure to harmful circumstances is directly
associated with fossil fuel-related emissions
[7]. According to The Lancet Commission on Pollution and Health .
[8] , 9 million premature deaths were associated with pollution in 2015,
representing 16% of all deaths worldwide. Environmental problems, such as
10. ozone depletion, forest destruction and acid precipitation are direct
consequences of the use of fossil fuels [8]. As suggested by the 2015 Paris
Agreement, the average global temperature increase should be limited to 1.5–
2 °C above pre-industrial levels.
Oil Rigs:-
5 Different types of oil Rigs
1. Barge Rigs:-
Barge rigs work in shallower waters, usually less than 20 feet deep. After being
floated to the drilling location, the hull is brought to rest on the ocean floor,
creating a stable platform for drilling. Many barge rigs operate in the Gulf of
Mexico and around the world.
2 .Submersible Rigs
In waters too deep for a barge, but less than 50-70 feet deep, a submersible rig
can be used.
Columns or posts are submerged into the water and filled to specific levels that
determine their depth. Drilling equipment on the platform above drives a
floating drill unit below.
3 .Jack-Up Rigs
As we move into deeper waters, a mobile platform called the “jack-up” rig
comes into play. It gets this name because it can be moved directly over the
location to drill or pump oil. The rig can be self-elevated (jacked up) from the
bottom of the ocean floor to secure it in place. Jack-up rigs are well suited for
shallow waters of 400 feet or less.
There are two types of jack-up rigs Cantilevered Jack-up, with a drilling derrick
mounted on an extending arm
Keyway or Slot Jack-up, which has a drilling unit on the platform over an
opening it drills through
4 .Platform Rigs
Many offshore oil rigs are anchored platforms. They use a steel framework
anchored to the ocean floor as a foundation for a surface drilling rig,
equipment, and living quarters. Platforms may drill in many directions from
11. this base, and they are broken down into specific types suited for various
depths.
5. Floating Rigs or Floaters
In very deep water, it is not practical to attach an offshore rig to the bottom of
the ocean. Floating oil rigs are kept in place by anchors or dynamic positioning
systems that keep them over target. There are several types of floaters in use
at various deep water drilling locations worldwide.
Worker Safety on All Oil Rigs
Working on any vessel or platform rig carries with it certain risks. Owners and
operators of rigs need to take steps to help protect their workers and provide
safe working environments. In the event they are negligent and workers are
injured, they can be held accountable under maritime law.
If you are an oil rig worker, seaman, or vessel worker and have been injured
while in the service of a vessel or ship, you could be entitled to monetary
compensation. To find out more about your legal rights and if you have
grounds for a personal injury lawsuit or “maintenance and cure,” contact
the Jones Act attorneys at Schechter, Shaffer & Harris, L.L.P.
Reference:-
Bartley, D.M. and C.V. Casal (1998) Impact of introductions on the
conservation and
sustainable use of aquatic biodiversity. FAO Aquaculture Newsletter 20 : 15-19.
FAO (2010) Fisheries and Aquaculture Information Statistics Services, Rome,
Italy.
Grosholz, E.D. (2005) Recent biological invasion may hasten invasional
meltdown by
accelerating .historical introductions. Proceedings of the National Academy of
Sciences, 102
:1088-1091.
Welcome, R.L. (1988) International introduction of inland aquatic species. FAO
Fish
Tech. Pap., 294, 318 p.