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Are Fisheries Resources Sustainable? Fishery Policy and
Management in the United States: Past, Present, and Future
Juan C. Levesque
Levesque Fisheries Research
Tampa, Florida 33544
The future of fisheries resources will depend upon the ability of natural resource managers to
implement sustainable development measures. This historical perspective and knowledge gap is
addressed for the country with one of the oldest and largest commercial fishery industries and most
complex fishery management in the world. The best available information are used to highlight
the history of fishery management and identify the main stressors impacting fishery resources in
the United States and globally. The review identifies much-needed solutions and opportunities for
improving fisheries management. Finally, several successful management approaches that are
currently being employed to improve fishery management are discussed. Arguable the greatest
concern to fishery managers is the exploitation of fish stocks by commercial fishing operations
and overfishing issues. However, climate change or climate variability and coastal development
(e.g., habitat loss and deteriorating water quality) are other major stressors that fishery managers
need to consider to conserve, protect, and recover fish communities. Given these global issues, it
is imperative that managers have a clear understanding of the causes and processes associated with
individual stressors, especially since some can cause compounded impacts on fish populations.
Fisheries management has started to evolve toward a more holistic ecological approach that
includes not only evaluating and assessing multiple species, but developing new analytical tools
for predicting and assessing impacts to the marine environment at large scales. Managers are even
starting to consider the impacts associated with climate variability, coastal development, and other
anthropogenic factors (e.g., potential oil spills) affecting populations.
Keywords: Biodiversity, Climate Change, Disturbance, Ecosystem Management, Stressors
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“If in a given community unchecked popular rule means unlimited waste and destruction
of the natural resources—soil, fertility, waterpower, forests, game, wild-life generally—which by
right belong as much to subsequent generations as to the present generation, then it is sure proof
that the present generation is not yet really fit for self-control, that it is not yet really fit to
exercise the high and responsible privilege of a rule which shall be both by the people and for the
people. The term “for the people” must always include the people unborn as well as the people
now alive, or the democratic ideal is not realized.”
— Theodore Roosevelt (1916)
Natural resources are among the most valuable commodities on earth. Some natural
resources (air, land, and water) are essential for human survival and many often constitute a large
percentage of local, regional, and national economies (Costanza et al. 1997; NJDEP, 2007; FAO,
2010). Costanza et al. (1997) stated that “the economies of the earth would grind to a halt
without the services of ecological life-support systems, so in one sense their total value to the
economy is inﬁnite.” Natural resources are not only valuable commodities (Groot et al. 2002),
but they have often influenced, shaped, and directed the development of society since early
civilizations (Hart and Reynolds, 2002). In fact, almost every previous society (e.g., Egyptians,
Romans, and Native Americans) has relied upon natural resources in one way or another (Hart
and Reynolds, 2002; Ross, 2003; Lotze et al. 2011).
Homer-Hixon (1999) revealed in his book that often powerful groups within a society
have used their political, economic, and social powers (socio-economic) to capture a resource by
supporting laws and institutions that managed natural resources or geographical areas (e.g.,
Jordon River Basin [ground water issues of the West Bank]). Natural resources are so important
to societies (past and present) that many nations have either signed international treaties or
implemented their own laws to protect and claim sovereign right over their natural resources
(Sanchirico and Wilen, 2007). For example, the United States established the exclusive
economic zone (EEZ) in the 1970s to claim power over marine resources off its coasts; the
United States’ EEZ is the largest of its kind in the world (TWH, 1983). The United States’ EEZ
extends 200 nautical miles off the coast, encompassing a diversity of marine ecosystems and a
variety of natural resources, including fisheries, energy, and minerals (TWH, 1983).
Internationally, the economic control of several natural resources (e.g., oil and hard-rock
minerals) has even caused, financed, and prolonged various civil wars throughout the world
(Homer-Dixon, 1999; Ross, 2003; Tabb, 2007). The attempt to control economically valuable
natural resources has also caused many international conflicts (Homer-Dixon, 1999; Ofori-
Amoah, 2004). For instance, competition for valuable fisheries resources off Canada’s Grand
Banks has caused international hostility between Canada and Spain on several occasions (Nixon,
1997). Take all you can before the other person or country does has been the general philosophy
of competition for natural resources since the beginning. Environmental scarcity of natural
resources (cropland, freshwater, and forests) is a growing concern for most nations, including the
United States. Some researchers believe that violent conflict will continue to rise over the next
decades throughout the world because of, or at least associated with, environmental scarcity
(Homer-Dixon, 1999). This critical issue is connected with the growth of the human population,
which is around 1.3 percent a year (Homer-Dixon, 1999). The debate and concern of population
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growth, economics, and natural resource shortage has a long history dating back to Confucius
and Plato (Homer-Dixon, 1999); societies have struggled with balancing these inter-related
relationships for centuries. Despite this bleak history, there is some evidence that common-pool
resource (e.g. fisheries) problems can be addressed using innovative approaches, such as
establishing polycentric governing systems (Ostrom, 1998). Complex adaptive governing
systems have been successful for managing salmon in the state of Washington (Ostrom, 1998).
Many of our natural resources (e.g., forests, rivers, and wildlife) have been influential in
shaping society and history, but one of the most prominent and valuable (dietary, monetary, and
socially) natural resources have been, and continues to be, fisheries resources (Huxley, 1883;
Sanchirico and Wilen, 2002). Human consumption of fish in 2007 accounted for 15.7 percent of
the world’s animal protein intake and 6.1 percent of all protein consumed (FAO, 2010). The
FAO (2010) states that as the human population continues to grow, the demand and reliance
upon fisheries resources will also increase to some infinite limit. What are the limits? Can
fisheries resources meet the demands of our growing human population? Homer-Dixon (1999)
reiterates Thomas Malthus’s notion that population growth will continue to the “limit of
subsistence and it is adjusted by famine, disease, and war.” The world-wide competition for
fisheries is currently as different scales. Depending on the species, competition for limited
fisheries is between individuals and among countries. Fisheries resources are so economically
valuable and important sources of protein that they are causing fish wars between nations
(Jennings et al., 2001).
Fisheries products are not only the most internationally traded food in the world (USAID,
2003), but commercial and recreational fisheries are among the most economically valuable
principle sectors of local, regional, and global economies (Gillet 2003; Mwangi, 2008; FAO,
2010). In 2006, jobs associated with fisheries in Kenya supported around 80,000 and 800,000
residents directly and indirectly, respectively (Mwangi, 2008). Fisheries resources also
contributed about one percent of Kenya’s gross domestic product in 2006 (Mwangi, 2008).
Almeida et al. (2001) reported that commercial fisheries in the lower Amazon have significantly
evolved in the last 30 years making this sector among the most important to local municipalities
in terms of jobs and income. In the United States, commercial fisheries are also important sectors
of many local, regional, and national economies. The National Marine Fisheries Service (NMFS)
reported that commercial fishing landings (4.3 million mt) were valued at $5.5 billion in 2014
(NMFS, 2016); however, this estimate did not include the total number of jobs supported or the
total business revenue (e.g., seafood dealers, equipment, restaurants) generated by commercial
The future of fisheries resources will depend upon the ability of natural resource
managers to implement sustainable development measures (Gillet, 2003), which WCED (1987)
defined as “development that meets the needs of the present without compromising the ability of
future generations to meet their own needs.” Important environmental concepts associated with
sustainable development are environmental degradation, traditional development objectives, and
process (Conga and Dabelko, 2004). One of the biggest challenges for natural resource managers
is emphasizing to society that natural resources need to be managed under the sustainability
premise since most natural resources are exhaustible. Historically, this has been a difficult
concept for societies to comprehend given that almost every generation has assumed it was
impossible to deplete their natural resources, especially fisheries resources (Huxley, 1883). Even
today, this false notion that fisheries are an endless resource still prevails throughout the world
(King, 1995). In many ways, this false historical perception has been driven by capitalism, free
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markets, and entrepreneurship philosophies rather than by science (life-history, fishery biology,
or population assessments). Because resource managers have historically used economics as the
basis to manage fisheries recourses, there are now many marine resources (e.g., elasmobranches
[sharks, skates, and rays], sea turtles, and marine mammals) that are dreadful examples of
Hardin’s (1968) well-cited publication “Tragedy of the Commons.”
The topic of sustainable fisheries has a long history that dates back to the days of Darwin.
Actually, one of the first speeches on fisheries and their sustainability was presented in 1883 by
Professor Thomas Henry Huxley, an accomplished, prominent, and respected biologist. In his
historical inaugural address to the International Fisheries Exhibition in London, Huxley (1883)
stated “I believe... all the great sea-fisheries, are inexhaustible; that is to say that nothing we do
seriously affects the number of fish. And any attempt to regulate these fisheries seems
consequently… to be useless”. Huxley’s assessment and believe at the time was that overfishing
or "permanent exhaustion" was scientifically unfeasible. He specifically pointed out that the cod,
herring, pilchard, and mackerel fisheries were inexhaustible. Huxley did however acknowledge
that some fisheries (e.g., salmon and oysters) could disappear with time under certain scenarios.
Despite Huxley’s influential standing in the scientific community, some biologists did not
support his simplistic theory on fisheries resources and their sustainability; Lankester (1884) and
Cleghorn (1885) both suggested that overfishing was indeed possible for many fishes. This
contentious debate about the sustainability of fisheries continues today even though many
fisheries throughout the world are classified by researchers as overfished, approaching collapse,
or reported as extinct (i.e., biologically and/or financially). In the United States, the fisheries
sustainability debate has recently escalated to various time-consuming legal administration
procedures (e.g., Freedom of Information Act and Data Quality Act) and lawsuits. Some of these
environmental lawsuits have been initiated from non-profit organizations believing that the U.S.
government has not done enough to protect fish stocks and prevent overfishing, while other suits
have been filed from commercial fishing organizations arguing that state and federal government
have gone too far in protecting fish stocks and marine resources (Buchsbaum et al. 2005;
Based on several legal settlement agreements and other pressing environmental concerns
(e.g., climate variability and coastal development), sustainability, biodiversity, and community
ecology are now at the forefront of domestic and international fisheries management. In a
attempt to protect, conserve, and recover fragile marine resources, fishery managers are now
beginning to explore new management options (Ostrum, 1998) since traditional methods have
mostly failed (NMFS, 1998; Tissot, 2005). Fishery management is diverging from the traditional
single-species to an ecosystem-based management (EBM) approach in an effort to better
understand, predict, and minimize the potential impacts and implications of anthropogenic
activities on communities and regions as a whole (ecosystems). Despite this ecological holistic
movement in fisheries management to consider various anthropogenic impacts on the whole
ecosystem, little progress has been in made toward using an EBM approach for various reasons.
Norse (1993) argues that marine conservation lags terrestrial conservation because we are
ignorant of the sea’s value and its vulnerability. Unfortunately, the scientific literature describing
regional marine fish communities are limited (NMFS, 1998), and baseline studies are lacking for
most regions around the world.
This historical perspective and knowledge gap is primarily addressed for the United
States, which has one of the oldest and largest commercial fishery industries and most complex
fishery management systems in the world. The best available information are used to highlight
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the history of fishery management and identify the main stressors impacting fishery resources in
the United States and globally. The review identifies much-needed solutions and opportunities
for improving fisheries management. Finally, several successful management approaches that are
currently being employed to improve fishery management are discussed.
2. REVIEW AND DISCUSSION
The Global Context and Challenges
“The sustainable development and management of aquaculture and fisheries systems can
only occur if these activities are well planned and integrated into the natural and social resource,
ecosystems, and farming systems contexts of the larger global context of which they are a part.”
Fisheries and aquaculture sectors, in comparison to other sectors of the world food
economy, are inadequately funded, poorly planned, and neglected by all levels of government
despite fishing being the largest extractive use of wildlife in the world (USAID, 2003). Fisheries
resources are one of the most valuable natural resources on earth, but natural and anthropogenic
stressors are negatively impacting populations around the world. Arguable the greatest concern
to fishery managers is the exploitation of fish stocks by commercial fishing operations and
overfishing issues. However, climate change or climate variability and coastal development (e.g.,
habitat loss and deteriorating water quality) are other major stressors that fishery managers need
to consider to conserve, protect, and recover fish communities. Brander (2013) emphasizes that it
is imperative that managers have a clear understanding of the causes and processes associated
with individual stressors, especially since some can cause compounded impacts on fish
populations. The effects and associated responses with the individual stressor can be classified as
additive, synergetic, or antagonistic (Blake, 2011). Without this information, management
measures could be ineffective. Population dynamics and community ecology of fishes are two
central concepts in fisheries management; however, research and management have been
historically directed at single-species rather than multi-species (an entire ecosystem), which has
hindered progress toward estimating the impacts and responses associated with key stressors.
2.1 Commercial Fisheries
Fisheries resources are essential to present and future societies. The FAO (1995)
indicates that commercial fishing operations are the only remaining global industry that exploits
a wild resource for food production. The capture of fishes has played a significant role in society
since early civilizations and it continues today (Lotze et al. 2011). It has been estimated that
fishing dates back some 90,000, 40,000 and 35,000 years ago with early civilizations using
spears, nets, and fish hooks to harvest fish from lakes, rivers, and oceans, respectively (Lackey,
2005). Historians have reported that artisanal fisheries (small scale commercial fishing
operations) evolved into larger scale operations by the Middle Ages (5−15 century), which was
driven by the development of transportation and fish preservation techniques (Lackey, 2005;
Scearce, 2009; Lotze et al. 2011). Commercial fishing operations have been valuable since the
1500s, but it was not until the 1950s with the development of large ocean-going vessels and
commercial fishing gears that commercial fishing operations rapidly expanded into the
influential, prominent, and profitable industries that they are today (Nixon, 1997; Lotze et al.
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Total world fisheries production (including fresh water and aquaculture) increased an
astonishing 500 percent from 20 to 100 million tons in four decades (FAO, 1995). Depending on
the nation, much of this increase in production was initiated, encouraged, and financed by
governments attempting to create jobs and generate revenue for their nation, including the United
States. Governments promoting and fostering the development of commercial fishing enterprises
and businesses dates back to the 1800s (Huxley, 1883), and it continues today for many
developed and developing countries (Mwangi, 2008). This alarming expansion and increasing
demand for fisheries resources has provoked declining fish stocks throughout the world; some
commercial fisheries have caused some species of fish and elasmobranches to be classified as
threatened or endangered (CITES, 2012). Around the world the sustainability of fisheries
resources is a major problem.
For centuries, fisheries resources have been classified and managed as renewable natural
resources since the “organisms of interest (e.g., fish, shellfish, reptiles, amphibians, and marine
mammals) usually produces an annual biological surplus that, with judicious management, can
be harvested without reducing future productivity (Lackey, 2005).” However, despite all the
attempts to manage fisheries resources it appears that many species in different locations
throughout the world are overfished (e.g., Almeida et al. 2001; Gillet, 2003). Overfishing has
been defined in a variety of ways by various governments and environmental organizations, but
the term can be commonly described as harvesting more fish than can be replaced
(overcapacity); it is the non-sustainable use of fisheries resources. Overfishing can also be
defined through cost/revenue and fishing effort curves, which represents the maximum catch that
can be harvested from a fishery without impacting the stability of the system (King, 1995). In
general, the sustainability of fisheries has been measured and assessed through the classical
maximum sustainable yield (MSY) or optimum yield concepts because these metrics can
demonstrate the “breaking point” of the system (Angelini and Moloney, 2007). The breaking
point of sustainability is the maximum level that fishing effort can increase to produce a positive
reciprocating increase in catch or yield (King, 1995). Schaefer (1954) estimated overfishing
through a population model approach, which basically demonstrated that increasing fishing effort
would eventually lead to a reduced MSY or harvest. For some species (e.g., sharks and whales),
the brink of sustainability has also been defined through life-history biology or economics.
Actually, biology and economics are often negatively correlated when it comes to the
sustainability of fisheries. Based on economic demand, commercial fishing operations usually
concentrate fishing effort on a particular species (target catch) until the catch has diminished to a
level that it is no longer economically profitable. At that point, new commercial fishery markets
are then established for the next “popular” or marketable species (Levesque, 2010), which
sometimes has been stimulated by the media or celebrity chefs (e.g., Chef Paul Prudhomme:
blacken red drum [Sciaenops ocellatus]; New Orleans, Louisiana). Adding to the problem,
overfishing includes the bycatch of many unmarketable fisheries resources that consist of
undersize target species, species with little to no economic value, and protected (threatened and
endangered) species (fish, marine mammals, sea turtles, and birds). Homer-Dixon (1999)
indicated that fisheries resources are often depleted or degraded from non-directed activities,
such as advancements in technology. In the past 50 years commercial fishing technologies have
advanced greatly with the development of radar, sonar, “live” weather, smart phone apps,
communications (texting), and environmental monitoring capabilities. Today, laptop computers
and smart phones allow fishermen to communicate with each other and access the internet,
monitor weather, and fishing forecasts while on the fishing grounds. These types of technologies
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have increased the fishing power and the catch efficiency of many commercial and recreational
fisheries, which has complicated the overfishing issue.
Through time, the economic market for fisheries resources has continued to emerge and
evolve under the law of supply and demand, which has occurred more swiftly than science has
advanced (Almeida et al. 2001; Levesque, 2010). Given this problem in the face of climate
variability and deteriorating water quality, the sustainability of many fisheries resources is
becoming more questionable, and it has even recently begun to impact the way the general public
purchases its seafood products (Parkes et al. 2010). In the United States, there are now various
certification programs and recommended lists that evaluate the sustainability of fisheries for
market purposes (ecolabeling); however, many of these programs have used different assessment
techniques and some of these procedures have been questioned for their lack of transparency and
robustness (Parkes et al. 2010). Moreover, most of these certification programs are not
developed, supported, or endorsed by government agencies; they are generally independent and
non-regulatory in nature. The sustainability of exploited fisheries is one of the biggest problems
Sustainability and conservation are two primary concepts that many marine resource
managers must consider when they develop management rules, regulations, and policy actions.
Recently, some positive progress has been made toward sustaining the commercial exploitation
of fisheries. In the United States, the NMFS reported there were more stocks and stock
complexes classified as stable, recovering, or recovered than there were stocks categorized as
overfished, subject to overfishing, or approaching overfishing status (NMFS, 2011). However,
despite this apparent status improvement for some fish stocks and stock complexes in the United
States, many species have yet to be fully assessed because of the lack of completed stock
assessments or adequate data. In addition, this recent fisheries assessment failed to consider
protected species, such as sea turtles, marine mammals, fish, elasmobranches, or sea birds
(NMFS, 2011). Also, the evaluation process did not consider non-commercial or bycatch species
that didn’t fall under a specific fishery management plan or subject to any biding regulatory or
conservation actions, such as escolar (Lepidocybium flavobrunneum), crocodile shark
(Pseudocarcharias kamoharai), and pelagic stingray (Pteroplatytrygon violacea). Protected and
bycatch species in the United States are usually assessed under a separate regulatory and
population status review processes, but obviously many of these stocks are in trouble for many of
the same reasons, such as commercial fishing operations, climate variability, and coastal
development (e.g., habitat loss and deteriorating water quality).
Global and regional fishery organizations (e.g., International Commission for the
Conservation of Atlantic Tunas) are charged with managing, protecting, and sustaining marine
resources for future generations, but despite the recovery of some fish stocks in U.S. waters,
many marine resources warrant additional and immediate conservation and management actions.
Although these appointed organizations are responsible for managing fisheries, they have yet to
incorporate and consider other stressors (climate variability and coastal development) that can
have dire consequences for fisheries and communities into their management processes.
Overfishing and declining fish stocks have been reported since the 1800s, but the problem
persists even today. The numbers of stocks classified as overfished continues to increase each
year in different locations around of the world. Overfishing has been a challenge for fishery
managers since the beginning. Actually, even the first FAO Fisheries Technical Committee
recognized the problem of overfishing back in 1946 and the group continues to meet and
deliberate about overfishing issues today. The FAO reported in the early 1990s that 69 percent of
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the world’s conventional species were fully exploited, overexploited, depleted, or rebuilding
from a depleted state (FAO, 1995). The FAO also concluded that most of the world’s fisheries
could not be sustained under the current harvest levels (FAO, 1995). Recently, the FAO (2010)
reported that 53 percent of the world’s fish species were fully exploited, 28 percent
overexploited, three percent depleted, and one percent recovering from depletion (FAO, 2010).
The terms overfishing, overfished, collapsed, and overexploited have been previously defined
and used inconsistently by scientists and managers, and some researchers would argue that these
terminology inconsistencies has even led to the exaggeration of the sustainability of commercial
fisheries (Branch et al. 2011). In contrast to previous studies indicating a more dismal status of
our global fisheries resources, only about 28–33 and 7–13 percent of all stocks were
overexploited and collapsed, respectively (Branch et al. 2011). These researchers also concluded
that the proportion of stocks classified as overexploited or collapsed had remained stable in
recent years. However, Branch et al. (2011) did stress that if the catch-based methodology was
robust and accurate, then stocks would “soon contribute little to species richness or ecosystem
function, which would lead to collapse and social and economic impacts on coastal
communities.” Despite this notion, Branch et al. (2011) believed the catch-based approaches
were bias and misleading in comparison to the biomass analytical approaches. Nonetheless, even
with some differences in the analytical approaches, the best available information showed that all
major fisheries resources have been impacted by anthropogenic activities to some degree. The
protection, recovery, and sustainability of fisheries resources is essential for future generations.
The scientific literature clearly demonstrates that overfishing has always been a problem
for marine resource managers charged with governing and sustaining fisheries resources. In fact,
even when Huxley presented his now famous inaugural speech to the International Fisheries
Exhibition back in the 1800s, the Atlantic halibut fishery had already collapsed, and the U.S Fish
Commission was investigating the declining fish stocks off New England (Goode and Collins,
1887). Today, almost every major commercially exploited fish and even those having no
significant economic value (e.g., sharks and rays) have declined to some extent. Commercial
fishing operations and overfishing practices have impacted a variety of fish (lower and upper
trophic level species including apex predators) all over the world. The scientific community
acknowledges that most species of sharks are at critical population levels, and some are
classified as endangered or threatened, and a few are extinct (Luiz and Edwards, 2011). Myers
and Worm (2003) and Baum et al. (2003) published several controversial articles in the early
2000s that demonstrated large predatory sharks (apex predators) in the western North Atlantic
Ocean had declined over 70 percent in less than 50 years because of commercial fishing
operations. In the tropical Pacific Ocean, Ward and Myers (2005) also reported that commercial
fishing operations had significantly reduced large pelagic sharks and tuna stocks. Although these
articles were perceived with some contention, most fishery scientists agreed that many fisheries
resources were being exploited at unsustainable levels and additional management measures
were long overdue.
Without question the loss of fisheries resources throughout the world is affecting
biodiversity at local, regional, and global scales. The loss of biodiversity can impact the earth
and society in a variety of ways (food, medicines, and aesthetic/recreational resources) (Norse,
1993). Biological diversity is threatened by many natural (e.g., disease and storms) and unnatural
factors (e.g., coastal development, invasive species, and habitat loss), including the
overexploitation by commercial fisheries activities (Norse, 1993). Though specific studies
focused on biodiversity are limited, there is some scientific evidence that shows the loss of
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fisheries resources is affecting the marine ecosystem on a global scale. Pauly et al. (1998) were
among the first to document the impacts of commercial fishing on community (ecosystem)
structure. Unfortunately, these researchers were able to prove that commercial fishing operations
throughout the world had fished “down the trophic level” from higher (tuna) to lower level
species (anchovies) in less than 50 years. In fact, Pauly et al. (1998) found that the average
trophic value of fish harvested had dropped in many geographical locations, including oceans
(3.4 to 3.1) and freshwater (3.0 to 2.8) systems. Their research showed the largest decline in
trophic level had occurred in the western North Atlantic Ocean (3.4 to 2.9). In general, when
commercial fisheries shift fishing effort from one species to the next (high to low trophic levels),
catch usually increases for a limited period before it decreases and/or even collapsing.
Regrettably, Pauly et al. (1998) reported the exact opposite trend, which was disturbing because
it suggested that species replacement had already occurred in the system.
A clear understanding of how these changes or declines in fisheries resources can impact
pelagic ecosystems is unknown, but recent reported declines of apex and keystone species
concerns most marine fishery scientists (Worm et al. 2003). As management is evolving toward
sustainability, marine scientists are now beginning to consider using large-scale marine protected
areas and various new analytical approaches as methods to protect pelagic biodiversity in the
open-ocean (Worm et al. 2003; Lucifora et al. 2011). New research is beginning to be emerge
that is focused on explaining and predicting potential changes in populations due to overfishing
using a biodiversity perspective. For example, Worm et al. (2003) reported that biodiversity was
highest in mid-latitudes and lowest in low and high latitudes. In terms of longitude, the
researchers found that biodiversity was highest in nearshore waters and lowest in offshore
waters. These findings were recently supported by Ward and Myers (2005), which also showed
that species richness for apex predators (sharks) was highest on continental shelves and mid-
latitudes (30°−40° north and south latitudes). In general, the findings from these studies are
concerning since they were based on fishery observer data and published articles, which
primarily relies upon commercial fisheries data. In particular, the finding are concerning because
the data showed that commercial fishing activities had historically concentrated their fishing
effort in the most biologically productive waters. More importantly, Worm et al. (2003) pointed
out that they did not know whether biodiversity hotspots in the past were more abundant, larger,
or located elsewhere since data were only available from the 1990s, which was about 40 years
after large-scale commercial fishing began to harvest apex species (i.e., swordfish [Xiphias
gladius] and tuna [Thunnus spp.]) in the open-ocean. Maintaining biodiversity is not only
essential for conservation, but it is also important for the sustainability of commercial fishing
operations (Worm et al. 2003), employment stability, and economic activity (NMFS, 1998).
Shifts in fish community structure have also been documented in the tropical Pacific
Ocean. Ward and Myers (2005) found that the overall biomass had declined by a factor of 10 and
the body size of several species (e.g., blue shark [Prionace glauca]) incidentally captured by
commercial fisheries had declined significantly by more than 40 percent. More interesting, they
also found that several small and formerly rare species (e.g., pelagic stingray and skip jack tuna
[Katsuwonus pelamis]) had increased in abundance, but these increases had not balanced the
reduction of large predators. Ward and Myers (2005) explained these increases, in smaller and
formerly rare species, were caused from commercial fishing operations reducing key predators.
These researchers were able to demonstrate that the total amount of energy in the system had
decreased significantly because of commercial fishing, but they could not explain how the
system had changed or compensated for such reductions in overall biomass.
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It is apparent that commercial fishing operations have negatively impacted fish stocks in
ways that are not only unsustainable, but these activities have caused losses in fisheries resources
that are irreversible and the impacts are cascading throughout the ecosystem. In the Adriatic Sea,
Lotze et al. (2011) reported some alarming findings for the Mediterranean Sea. First, they
showed that 98 percent of major marine resources in the Adriatic Sea had declined significantly
(50%) and 11 percent had become locally extinct since early civilizations first began harvesting
fisheries resources in the region. Second, they found that changes in species abundance and
diversity had altered ecosystem structure and function. Lotze et al. (2011) found that large
predators and consumers had declined more significantly than smaller macrofauna, especially in
the 19th and 20th centuries. Moreover, they found that marine invertebrates (oysters) had declined
25 percent, which they said probably explained why water quality had declined over time. Along
with continued declines in fisheries resources, the researchers stated that the number of invasive
species in the Adriatic Sea had also continued to increase each year. In general, Lotze et al.
(2011) showed that as species diversity decreased with time, trophic levels had become more
simplistic and less complicated and connected. In the Adriatic Sea, commercial fishing has
caused lower trophic levels to increase and higher trophic levels to decrease. The researchers
also concluded the greatest food-web change occurred when a species became locally extinct.
Constructing binary networks to evaluate trophic structure, they found that as a species became
locally extinct, the system became less robust and more vulnerable to secondary extinctions and
trophic collapse. The consequences of reducing marine biodiversity on ecology, society, and the
economy remains unclear, but to move forward changes in how fisheries resources are managed
is warranted and long overdue.
2.2 Climate Variability
Fish populations, communities, and entire marine ecosystems have been dramatically
impacted by commercial fishing operations, but they have also been negatively influenced by
changes in their physical environment caused by climate variability. According to Duly et al.
(2011), global surface temperature has increased 0.6°C, sea level has increased 10−20 cm, and
precipitation has increased 1% per decade in the northern hemisphere. It is estimated the mean
global surface temperature will increase between 1.4 and 5.8°C by 2100 (Duly et al. 2011). In
addition, global acidity has decreased by more than 0.1 units since the preindustrial period and it
is anticipated that pH will continue to decrease by 0.10−0.35 units by the end of the century
depending on the region (Doney, 2010; Denman et al. 2011). Researchers have also predicted
that hypoxia conditions will increase with time (Stramma et al. 2008); DO levels have already
decrease significantly in the high latitudes of the North Pacific Ocean (Whitney et al. 2007).
In several ways, climate variability is a natural process (El Niño—Southern Oscillation
(ENSO) and decadal variability in ocean climate on the ecosystem off the west coast of South
America), but some researchers have linked global climate change to the increase in
anthropogenic greenhouse gas emissions associated with fossil fuels (Duly et al. 2011). In
general, the scientific community is in disagreement of the root cause, but regardless of the cause
and reason for the recent global change in climate, there is substantial scientific evidence that
climate variability has already had profound effect on terrestrial and marine environments,
especially marine fish communities. In addition, some scientists have predicted that cumulative
impacts will be even more distressing to marine ecosystems than individual climate change
consequences (Ainsworth et al. 2011). Besides marine communities, climate change has also
negatively impacted freshwater fish (Fricke et al. 2007; Kaufman and Allen, 2008). For instance,
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research by Taylor (2008) showed that pink salmon (Oncorhynchus gorbuscha) fry in Alaska
have continued to migrate increasingly earlier over the past 34 years; Taylor (2008) indicated the
implications were uncertain to the overall health of pink salmon in Alaska. Changes in our
climate is affecting individual species and aquatic ecosystems all over the world.
Numerous researchers have predicted climate change will impact primary production
(Gnanadesikan et al. 2011) and fisheries in a variety of ways (Kennedy et al. 2002); some
predicted changes (e.g., oceanic temperature rise, sea level rise, increased precipitation, glacial
melt, frequency of extreme events (storms), and severity of ENSO) are expected to impact
fisheries more severely than others (Dully et al. 2011). Changes in phytoplankton in the North
Pacific are expected to impacts fisheries resources (Jang et al. 2011; Polovina et al. 2011).
Depending on the region, fish catch will either decline (temperate and equatorial upwelling) or
improve (subtropical) (Polovina et al. 2011). According to Muhling et al. (2011), anticipated
changes in climate suggests that even large pelagic species could be impacted, such as bluefin
tuna (Thunnus thynnus) and blue marlin (Makaira nigricans) (Su et al. 2011).
Brander (2013) broadly categorized the climate variables potentially impacting fisheries
resources as the following: atmospheric-sea surface (wind, cloud cover, waves, and sea level),
chemical and physical (temperature, salinity, pH, and oxygen), and dynamic (currents,
stratification, turbulence, upwelling, and frontal processes). The scale and response by the
species or system will depend on the magnitude of the climate change and sensitivity of the
species (Brander, 2013). Climate change can influence an individual species or an entire system
directly and/or indirectly (predator-prey relationships).
Over the last decade scientific studies focused on evaluating the impacts associated with
climate change on individual fish species and marine communities has steadily increased around
the world; this topic has even been the focus of various workshops (Russell et al. 2011), fisheries
management reports (e.g., Gregg et al. 2016), and non-profit organization documents (Treece,
2016). Climate variability has caused water temperature, mixed depth layer, and currents to vary,
which has led to changes in fish spatial distribution. According to Bell et al. (2009), the basic
changes in fish distribution and geographical range related to climate variability include the
following: (1) expanded distributions of warm water fish and contracted distributions of cold
water fish (i.e., spatial shift and community structure); (2) occurrence of key prey species in
higher latitudes; and (3) dispersal and recruitment of fish larvae. The researchers also point out
that climate variability can impact reproductive success, recruitment processes, survival and
growth of specific fish and their prey. Increases in sea level rise, precipitation, and storms caused
by climate variability can even impact the structural/complexity of marine habitats, such as coral
communities (Bell et al. 2009). In Brander’s (2015) review of the scientific literature, he also
found that climate change (rising water temperature) could cause the mean asymptotic size of the
fish assemblage in an area to decline. The review showed that rising water temperatures could
also alter spawning, maturation, and natural mortality.
Combined, all of these changes can alter commercial fishing operations, economics
(employment, exports, and gross domestic product), and fishing communities around the world.
The ICTSD (2010) and Mohammed and Uraguchi (2013) stressed that many fishing fleets
around the world were economically vulnerable to climate change-driven impacts, especially
those from developing countries (West and Central African countries). The researchers indicated
that small-scale and artisanal fisheries were the most vulnerable to climate variability given their
inability to adapt (limited resources and capacities). In many developing countries (e.g., Malawi,
Bangladesh, and Vietnam), fisheries resources provide not only employment, but nutrition and
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health benefits (Williams and Rota, 2014; Karim and EnamulHagque, 2015); alternative options
are limited in developing countries.
Scientists around the world have predicted and demonstrated that climate variation has
had significant impacts on fisheries resources from the North Sea to the tropics. Primarily,
researchers have shown that spatial distribution is the key response associated with climate
variability. They also stated that most species react negative to warm water temperatures and
positive to upwelling depending on the species and geographical location (Sydeman and
Thompson, 2014). Researchers have predicted that changes in species distribution and catch in
the northeast Atlantic may also be associated with changes in oxygen content, acidity, and
phytoplankton community dynamics (Cheung et al. 2011).
In general, scientist have documented that warm-water species with smaller maximum
body sizes have increased in abundance throughout northwest Europe, while cold-water species
with larger body sizes have decreased in abundance (Pinnegar et al. 2016). Using fisheries
survey data collected in the North Sea, various researchers have demonstrated that fish
distribution has shifted between 48 and 403 km, and demersal fish have moved to deeper colder
waters at a rate of around 3.6 m per decade over the past 30 years (Beare et al. 2004; Perry et al.
2005; Duly et al. 2008). This pattern has also been documented in small pelagic fish and species
that prefer relatively shallower depths. Building upon earlier studies, Dully et al. (2011)
highlighted that various southern-distribution (warm-temperate) species (John Dory [Zeus faber],
red mullet [Mullus surmeletus], anchovy [Engraulis encrasicolus], and sardine [Sardina
pilchardus]) have expanded their range northward (Quero, 1998; Beare et al. 2004; MacKenzie
et al. 2007). Likewise, Perry et al. (2005) documented the extended northern movement and
depth range of plaice (Pleuronectes platessa), a southern species, in the Northeast Atlantic
Ocean. Engelhard et al. (2011) examined long-term distribution changes of North Sea sole and
plaice over 90 years, and demonstrated that the distribution shift (direction and depth) in plaice
was caused by climate change, but both climate and fishing influenced the distribution shift of
sole. In the southern North Sea, Hofstede and Rijnsdorp (2011) also found that warm water
species richness and annual mean size had declined during warming periods, which they
indicated was independent of fishing pressure. Spatial distributional changes (i.e., ratio of
southern to northern species) have also been predicted and documented in the Bering Sea for
several species, such as sockeye salmon (Perry et al. 2005; Farley et al. 2011) and Walleye
pollock (Theragra chalcogramma) (Hunt et al. 2011). Climate variability is also anticipated to
impact sprat (Sprattus sprattus) and associated fisheries in the Baltic Sea (Voss et al. 2011).
Scientists are concerned about expected shift changes in species assemblages (positive and
negative) off SE Australia caused by ongoing and predicted climate changes (Fulton, 2011).
Besides particular species and fish communities, researchers have also observed changes in
cephalopod populations caused by ongoing climate change; Hastie et al. (2009) indicated that
squid are becoming more prevalent in the North Sea. Climate variability has impacted a variety
of species all over the world.
Understanding and explaining the reasons why species alter their distribution in response
to changes in the environment is complicated and unclear. According to Pinnegar et al. (2016),
“many processes interact when considering fisheries and climate change, and these are a
manifestation of both biological and human processes.” They stressed that responses to the
environment do not occur in isolation, many are synergistic, and rarely are they linear. Duly et al.
(2011) indicated that changes in spatial distribution caused by rising water temperature can either
improve or diminish year class strength depending on the species and location. Many researchers
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(Brander and Mohn, 2004; Pawson, 1992; Cook and Heath, 2005) have reported changes
(negative and positive) in year-class strength (i.e., recruitment) for a variety species (cod, seabass
[Dicentrarchus labrax], whiting [Merlangius merlangus], and saithe [Pollachius virens]) from
the English Channel to the North Sea. Besides changes in year-class strength, researchers have
also reported that spawning and recruitment has occurred earlier than usual for various species in
the North Sea (Greve et al. 2005; Fincham et al. 2013).
In the North Pacific Ocean, Noakes and Beamish (2009) found both positive and
negative correlations associated with catch (e.g., Pacific halibut [Hippoglossus stenolepis] and
Pacific cod [Gadus macrocephalus]) and regime shifts caused by variations in the Pacific
Decadal Oscillation and other indices of climate. Based on their findings, the researchers stated
there was clear evidence that climate change had altered valuable fish stocks in the North Pacific
Ocean. However, they went on to admit the response depended on the species’ life history
characteristics and state of the ecosystem at the time the climate varied; the response varied by
individual species. Although Noakes and Beamish (2009) found various species were grouped in
their response to changes in the environment, they could only speculate to the reasons why they
responded similarly. For instance, Pacific hake and jack mackerel (predators) adjusted their
distribution in response to the availability of prey, while some predators, such as Pacific chub
mackerel (Scomber japonicas) and Chinook salmon (Oncorhynchus tshawytscha) were clustered
in a different grouped for some unknown reason. Elucidating the details of why some species
migrate and others adapt to climate variability is not a straight forward process (Noakes and
Beamish (2009). In the eastern North Pacific Ocean, climate change is positively affecting chum
(Oncorhynchus keta) and pink salmon (Oncorhynchus gorbuscha) abundance, but it is also
negatively affecting coho (Oncorhynchus kisutch) and Chinook salmon (Oncorhynchus
tshawytscha) (Irvine and Fukuwaka, 2011). Pinsky and Byler (2015) examined 154 marine fish
stocks around the world and found that 25 percent have collapsed; however, they stated the
reasons were complicated and not straightforward. Although they indicated that overfishing was
the primary root cause for the collapse, Pinsky and Byler (2015) found that various explanatory
factors (growth rates and climate change) were also important. Overall, collapse was explained
by a combination of overfishing, life-history characteristics and climate variability. Pinsky and
Byler (2015) examined the variability in SST, but indicated that other indicators (primary
productivity, upwelling, and climate regime shifts) of climate change might be better for
explaining potential impacts to fish. Assessing potential changes in climate and associated
impacts to fish populations is complex.
In 2008, the first report by an international group evaluating climate change impacts on
key fishery species in the North Pacific Ocean was published (Beamish, 2008). The researchers
considered primary fisheries within their respected regions (Canada, China, Japan, Korea, Russia
and the United States) and attempted to link the stock to predicted changes in climate associated
with ENSO on a 3 to 5, and 30 to 60 year scale. The synopsis by Beamish and Noakes (2008)
indicated that environmental changes and associated commercial yields varied by geographical
location and species. Anticipated impacts varied from lowering productivity of chub and jack
mackerel in Korean and Chinese fisheries to improving Pacific salmon stocks and Pacific ocean
perch (Sebastes alutus) year-classes off the west coast of Canada. However, they acknowledged
that the science was unclear, the climate implications were variable, and inconsistent.
Climate change has also impacted fisheries resources in the western North Atlantic
Ocean. In the Northeast region of the United States, various climate metrics have changed over
the past 116 years and caused various changes to fisheries. Horton et al. (2014) highlighted that
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air temperature (2°F), precipitation (5 inches), coastal flooding, and the number of extreme
precipitation events (i.e., storms) had increased between 1895 and 2011. All of these ongoing
changes have and will continue to influence the regional dynamics and community ecology of
fishes. Among the first to examine the relationship between climate variability and the spatial
distribution of fish stocks in the northeast were Nye et al. (2009). To set up their study, they
hypothesized that rising water temperatures would induce at least one of the following responses:
a poleward shift in the center of biomass, an increase in the mean depth of occurrence, a range
expansion/contraction depending on the species, or no distributional shift. They also
hypothesized these responses would be mediated by changes in relative abundance. Using data
obtained from an ongoing NMFS 40 year (1968 to 2007) bottom trawl survey program, they
found that many stocks (67%) spanning several taxonomic groups (e.g., alewife [Alosa
pseudoharengus], American shad [Alosa sapidissima], silver hake [Merluccius bilinearis], red
hake [Urophycis chuss], and yellowtail flounder [Pleuronectes ferruginea]), life-history
strategies, and rates of fishing pressure had moved northward, and to deeper waters. Although
some species expanded their northern range, a few contracted their northern range. The
researchers pointed out that distributional changes were highly dependent on the biogeography of
each species. They found minimal distributional changes for stocks limited to the Gulf of Maine,
but mean depth of these stocks increased and stock size decreased. Nye et al. (2009) attributed
the shifts in the mean center of biomass to the large-scale temperature increase and changes in
circulation, represented by the Atlantic Multidecadal Oscillation.
Wood et al. (2009) examined the warm-water fish community in Narragansett Bay and
Long Island Sound and found, for the first time, that abundance of warm-water species had
increased from 1987 to 2000 even though most had been collected in the later years (1994, 1998,
and 2000). As expected, warm-water species preferred warmer conditions with 80 percent
collected in temperatures between 17 and 21°C, and 100 percent collected at 23°C. Despite their
findings, Wood et al. (2009) did state that not every year when water temperatures were warm
did they observe an increase in warm-water species, which suggested there might be other
contributing factors (transport mechanisms). They reported the Gulf Stream Current played a
major role in transporting larvae and juveniles, and hinted that it could weaken if water
temperatures continued to increase over time.
Similarly, Pinsky and Fogarty (2012) demonstrated that American lobster (Homarus
americanus), yellowtail flounder (Limanda ferruginea), summer flounder (Paralichthys
dentatus) and red hake (Urophycis chuss), and associated commercial fishery landings had
shifted northward along the east coast (Virginia to Maine) over the past 40 years. Overall, they
attributed this shift in distribution to a change in preferred water temperature. Pinsky and Fogarty
(2012) discovered the preferred temperature of species caught off Virginia, Rhode Island,
Massachusetts, and Maine had increased from 1963 to 2010. The trend was significant in
Massachusetts and Maine, but it was not in Virginia or Rhode Island. In a complimentary study,
Pinsky et al. (2013) demonstrated the northward and downward movement of American lobster,
black sea bass [Centropristis striata], and red rake in the northeast from 1968 to 2015. This
phenomenon has also been predicted for gray snapper (Lutjanus griseus) another economically
valuable species found along the east coast (Hare et al.2012).
More recently, Howell and Auster (2012) discovered that the abundance of cold-water
species had decreased and warm-water species had increased in Long Island Sound, a semi-
enclosed estuary, during 1984 through 2008. Specifically, they found that the number of cold-
water species declined and warm-water species increased in spring. They also documented mean
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catch and species richness increased in autumn, but mean catch decreased in spring and species
richness was similar. Howell and Auster (2012) attributed these responses to long-term warming
water temperatures. Their analyses showed that species were sensitive to water temperature, but
also mentioned that commercial fisheries likely impacted abundance for some of the species.
Kleisner et al. (2016) also revealed that fish assemblages that preferred shallower,
warmer waters tended to migrate west-southwest to shallower waters (Gulf of Maine), while
those associated with relatively cooler and deeper waters shifted to deeper waters over time off
the northeast coast of the United States. Fish assemblages associated with warmer and shallower
water along the continental shelf from the Mid-Atlantic Bight to Georges Bank shifted northeast
along latitudinal gradients, but there was little change in their depth distribution. The data
indicated the shift in depth distribution for southern species was inconsistent, but tended to be
toward deeper waters. The authors indicated spatial expansion and contraction of species
assemblages in each region basically corresponded to preferred water temperature and it was
inversely related to assemblage biomass. In summary, Kleisner et al. (2016) suggested that ideal
water temperatures for particular assemblages were decreasing over time, corresponding to
decreases in the spatial extent of some fish assemblages.
Scientists have shown and continue to demonstrate that changes in climate are having
drastic impacts on fish communities world-wide. Despite these documented changes, it is
difficult to predict how these changes (direct and indirect routes and interactions) will ultimately
effect biodiversity, ecosystem structure, function, and overall health in the long-term; “there are
substantial areas of uncertainty (Staudinger et al. 2012).” The interactions and pathways of
multiple human-induced, environmental, and climate stressors can cause a variety or responses
(linear, non-linear, additive, or synergistic) to species assemblages (Staudinger et al. 2012). As
with any natural and anthropogenic impact, the magnitude and intensity of the reaction will
depend on the individual species (intra and inter-relationships) and their ability to cope or evolve
as a function within their ecosystem (i.e., vulnerability). As previously highlighted, researchers
predict that climate change will cause assemblages to evolve, but they also expect many species
will become extinct (Maclean and Wilson, 2011). Climate change will also change the
distribution of fishing effort given the availability of specific species in a region (Tseng et al.
2011). Given these potential profound implications for global fisheries resources, scientists are
attempting to incorporate expected climate change impacts into the fisheries management
process, such as preparing for emerging fisheries, accounting for impacts in stock assessments,
and considering dynamic spatial boundary changes (Pinsky and Mantua, 2014). Pinsky and
Mantua (2014) indicated that it will be important to coordinate with other regions and to consider
socio-economics since many communities rely heavily on fisheries for employment and diet.
Link et al. (2015) emphasized that effective management and strategy will depend on having key
model inputs, such as mechanisms of change. The authors pointed out that the reasons and
mechanisms behind risk, and what actions might help reduce risk and increase resilience was
essential for developing management options. Establishing reference points will be important to
fishery managers so they can detect early changes (i.e., adaptive management) in the system
(Link et al. 2015); it’s essential that managers accurately interpret past and present observational
data (physical and chemical) trends and consider uncertainty in parameter estimates (Planque et
al. 2011). Murawski’s (2011) overview of the Sendai Conference on the fishery impacts
associated with climate change emphasized various positive outcomes, but indicated
improvement in the science included incorporating various impact factors into future
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assessments. Murawski (2011) also recommended that researchers should focus less on
individual species and more on understanding species interactions and integrating trophic
dynamics in future climate change studies.
2.3 Coastal Development
Another major anthropogenic impact that has negatively affected fisheries resources
around the world has been coastal development, especially in the United States. The foundational
and historical issue is the preference for people to settle, reside, and rely on its coastal resources
(Crain et al. 2009); this trend continues today. In the Philippines, over 70 percent of residents
reside within 10 km of the coast, and most (75%) settlements are classified as coastal
communities (Padilla, 1996). This trend is similar all over the world, including the United States.
In fact, the EPA (2006) predicts 75 percent of the global population will live near coastal areas
Many researchers have reported that past and present coastal development (buildings
[industrial, commercial, and residential], armored shoreline [seawall and bulkhead], and
breakwaters/jetties) has transformed the coast and caused a variety of problems for fish
communities (Bulleri and Chapman, 2010). Nellemann et al. (2008) stated that coastal
development would impact 91 percent of all inhabited coast and lead to more than 80 percent of
all marine pollution by 2050. They indicated the major issues associated with coastal
development were deforestation, destruction of mangroves, sewage, and river run-off. They also
predicted the number of hypoxia (DO levels < 2 mg/L) dead zones around the world would
increase given the projected growth in coastal development and associated pollutant run-off.
Hypoxia is growing problem in the United States, especially since the second largest “dead
zone” in the world is located off the Louisiana and Texas coasts; the largest dead zone is in the
Baltic Sea (Committee on Environment and Natural Resources, 2010). Globally, the distribution
of hypoxia zones is near the coast. Rabotyagov et al. (2014) emphasized that hypoxic zones are
usually found downstream of major population centers and/or land impacted by agriculture. In
the United States, hypoxia is a major problem along the coasts of the Gulf of Mexico, South and
Mid-Atlantic regions. The Committee on Environment and Natural Resources (2010) identified
the Mid-Atlantic region as having the largest eutrophication problem.
One of the biggest issues associated with coastal development is urban run-off because it
reduces overall water quality and health, especially since sewage treatment is either limited or
absent in many parts of the world (Nellemann et al. 2008). According to UNEP (2006), around
60 percent of untreated waste water is discharged into the Caspian Sea, and 80-90 percent is
discharged into the ocean from Latin American/Caribbean, African, and Indo-Pacific countries.
In the United States, the EPA (2002) indicated urban run-off was the leading water quality
problem for estuaries. Despite the federal government amending and establishing the basic
structure for regulating pollutant discharge into the waters of the United States (33 USC §1151),
there are still many examples of urban run-off affecting water quality and coastal communities.
The EPA (2005) reported that much of the problems are linked to waste water treatment plants,
municipal, agricultural, and septic systems. For instance, Tilburg et al. (2015) found that water
quality varied in space and time at three major coastal (Kennebec, Androscoggin, and Saco
rivers) watersheds. In general, concentrations of fecal (E. coli and total) coliform were higher
along the coast than they were in the rivers. The concentrations of fecal coliform varied by
season with the highest occurring in late summer. The authors indicated water quality was
related to river discharge and wind, but the sources of fecal coliform were probably linked to
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wastewater treatment plants in the area, and human activity (beach goers and pets). They
attributed the seasonal variability in fecal coliform to the direct relationship with the local
seasonal population (i.e., tourism); sewage outfall is also varies by season.
Other anthropogenic stressors associated with coastal development include, but are not
limited to habitat (e.g., nursery grounds, recruitment, and spawning) loss, and increased sediment
and nutrient inputs (point and non-point sources) (Blake, 2011); coastal development has altered
the hydrology in many coastal areas. Coastal development has degraded and damaged marine
ecosystems all over the world with many researchers claiming habitat loss is probably the most
detrimental impact since it often completely removes or converts coastal habitat (Crain et al.
2009). In many coastal areas, dredge and fill operations and engineering practices have
accelerated the expansion of coastal development and population growth. Dredge and fill is a
technique used to construct various infrastructures, such as buildings (residential or commercial),
roads, levees, dams, or seawall/breakwaters.
Dredge and fill operations have destroyed valuable nursery habitat (mangroves, salt
marshes, oyster beds, and seagrasses) for a variety of nearshore and coastal fish (e.g., bluefish
[Pomatomus saltatrix] and striped bass [Morone saxatilis]). Coastal development has also
significantly impacted wetlands that support the prey (Atlantic silverside [Menidia menidia] and
sheepshead minnow [Cyprinodon variegatus]) of many valuable (sport and commercial) fish,
such as southern founder (Paralichthys lethostigma). Lotze et al. (2006) indicated that 67 percent
of wetlands, 65 percent of seagrasses, and 48 percent of other submerged aquatic vegetation has
been lost over the past 150 to 300 years. In other regions (e.g., Philippines), coastal development
has consisted of removing valuable mangrove and salt marsh communities and converting them
to aquaculture and agriculture land use areas (Padilla, 1996). Unfortunately, some of these land-
use conversions have been unsuccessful so many have been left idle or abandoned (Padilla,
1996). Officials in the Philippines have attempted to reclaim these areas for residential,
commercial, and industrial (ports and harbors) purposes, but it has been limited (Padilla, 1996).
Reduced water quality associated with coastal development can negatively impact marine
fisheries resources in a variety of ways, including the loss of biomass via direct mortality.
Hypoxia has led to fish kills around the world and throughout the United States (e.g., Paerl et al.
1999). Other consequences associated with hypoxia include habitat loss, behavioral response
(e.g., avoidance and changes in movement patterns) and spatial distributional modifications in
fish (Committee on Environment and Natural Resources, 2010). Low DO levels has even caused
changes in fish community structure. Besides marine systems, poor water quality has also
adversely affected fish diversity in freshwater systems. For instance, Mondal et al. (2009)
discovered several ecological metrics (diversity, evenness, and dominance) that were either
positively or negatively correlated with specific water quality parameters in several lakes in
India. Specifically, they found that declining depth and increased salinity had the most profound
effect on the fish community. They attributed declining depth and increased salinity to siltation
caused from regional development and subsequent population increase. Overall, Mondal et al.
(2009) found the number of dominant species was declining suggesting the community structure
was changing with time.
Direct and indirect consequences associated with coastal development have impacted and
continues to alter marine coastal systems and fish communities. To examine this problem,
Bilkovic and Roggero (2008) assessed possible connections among (1) subtidal habitat, (2)
shoreline condition, (3) upland development, and (4) nearshore nekton communities in the James
River, Virginia; the James River is the largest tributary to Chesapeake Bay. The authors chose
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this location because the James River is presently being transformed and converted from forested
and agricultural land to residential and commercial land at a rapid rate. They indicated urban
development was causing problems for fish communities. Evaluating eight different fish
community metrics, and several land-use parameters, Bilkovic and Roggero (2008) found that
the lowest fish community index (measurement of biotic integrity) was associated with the man-
made bulkhead shoreline. They also found that salinity and DO concentrations were connected to
several ecological metrics. Moreover, the researchers discovered there were different ecological
thresholds that correlated with different land use (urban and suburban) buffer zones (100, 200,
1000 m). Overall, the lowest integrity sites had the highest development and/or bulkhead
shoreline, while the highest integrity sites had the lowest development with natural or riprap
Coastal development has impacted almost every region in the world. The Philippines is a
country that has undergone extensive coastal development and fisheries expansion over that past
few decades. Panay Island, is considered free of pollution, but Monteclaro et al. (2010) reported
fishermen from the communities of Dumangas, Roxas City and Ibajay indicated waste from
aquaculture, animal culture, mining, domestic households, garbage, and navigation operations
was affecting their fishing coastal fishing grounds. They also indicated sedimentation was
causing poor water conditions and subsequent oyster mortalities. Monteclaro et al. (2010)
suggested coastal areas were affected more by anthropogenic wastes than nearshore and offshore
areas. Overall, fishermen perceived pollution had reduced their catch and income, especially
since they had incurred additional operating costs searching for alternative fishing grounds (i.e.,
In the southeast United States, coastal development has impacted the natural resources of
every state, especially Florida. Given the population demand, Tampa Bay, located on Florida’s
west coast, has undergone great urban transformation since the 1970s, particularly in the last
twenty years (urban development tripled) (Xian et al. 2007). To assess the influence of coastal
development (natural, industrial, man-made, and urban) on small tidal tributaries and mangrove
fish communities in Tampa Bay, Krebs (2012) examined, compared, and quantified various
nekton-based metrics (abundance, species richness, community structure, body condition,
reproduction and predation risk). Interestingly, results showed there was no difference in total
nekton density or species richness as a function of land use. However, the findings showed
economically important taxa were 2-4 times more abundant in undeveloped and industrial creeks
than urban sites; there were nearly twice as many taxa. Krebs (2012) found the community
structure was significantly different among tidal tributaries and land-use classes. The greatest
dissimilarity in nekton-community structure was found between urban and non-urban tributaries;
non-urban tributaries had a similar fish community. Examining fish body condition, Krebs
(2012) discovered it differed among land-use classes for six of nine nekton taxa. In addition,
there was a significant difference in fecundity and other reproductive metrics as a function of
land-use for a few fish; there were higher measures in non-urban tributaries than urban
tributaries. Krebs (2012) indicated characteristics of urban lands (high impervious surface,
altered shorelines, low mean salinities and hypoxia frequency) best explained the observed
variation in nekton metrics among tidal tributaries in more natural watersheds. In general, the
results showed urban creeks supported a less diverse nekton fish community and had a lower
density of economically important taxa than observed in natural tributaries. The author indicated
many of the potentially explanatory factors connecting variation in fish communities between
urban and non-urban settings were interrelated and correlative (e.g., area of urban land uses,
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impervious area, extent of shoreline modification), which made it challenging to pinpoint
causative. However, Krebs (2012) stated urban development could be linked to degraded habitat
quality in freshwater and tidal tributaries. Krebs (2012) also suggested there was a direct link
between impervious surface and fish habitat in tidal tributaries given the differences in fish
community structure, species-level densities (including economically important taxa), energetic
condition, and reproductive potential of a few species between urban and non-urban tidal
Similar to other regions, coastal development in Europe has been extensive, and the trend
continues. Airoldi and Beck (2007) estimated that 80 percent of the coast has already been
degraded or lost, which has affected a variety of valuable nearshore species. Although large
construction projects have caused instant direct affects, small incremental construction projects
can also alter community structure over time (Sundblad and Bergstrom, 2014). Coastal
development in Stockholm archipelago has steadily increased since the mid-1900s with the
construction of jetties, marinas, and the rise of dredging (Sundblad and Bergstrom, 2014). In
2014, Sundblad and Bergstrom showed how relatively minor shoreline construction (jetties,
marinas, and other constructions extending into the water) projects (1960−2005) can reduce fish
spawning habitats (northern pike [Esox Lucius], Eurasian perch [Perca luviatilis] and roach
[Rutilus rutilus]). The researchers found the number of coastal construction projects had steadily
increased (jetties: 1.5%/year) since the 1960s (4.9 jetties/km shoreline). They also revealed that
70 percent of available fish spawning habitat had at least one man-made structure per 100 m
shoreline, and 40 percent had more than three man-made structures per 100 m shoreline. As
expected, the greatest annual rate of habitat degradation was associated with larger population
centers. Based on this rate, they projected all available fish spawning habitat (submerged
vegetation) would disappear in 60 years. The authors did not estimate the direct impact to
fisheries resources, but they did point out that managers should consider construction rates and
evaluate cumulative impacts during their approval process.
In the Gulf of Mexico, Lowe and Peterson (2014) used landscape ecological techniques
to investigate how coastal development had affected the fish community along the Mississippi
coast. The researchers found tidal creeks located in natural salt-marsh areas supported a nekton
assemblage that was significantly different from those in partially or completely urbanized
saltmarsh landscapes. They indicated that resident and transient nekton species that had specific
habitat requirements were more likely to be impacted than mobile species that could exploit
multiple habitats. Lowe and Peterson (2014) indicated the patterns were less clear for
macroinfaunal assemblages, but did find they were comparatively less abundant in completely
urbanized salt-marsh landscapes than in either natural or partial urbanized areas suggesting poor
habitat quality for nekton species.
Anthropogenic activities are impacting fish populations around the world, but managers
have primarily managed fish stocks from an exploitation perceptive without considering other
factors that can influence populations. In addition, fish stocks around the world have been
managed using the single-species approach. It is apparent this management style has mostly
failed given the current status of many fish and elasmobranch stocks, and the growing concerns
about climate change and coastal development. Despite managers continuing to use this
conventional approach, it is interesting that early fishery researchers in the United States focused
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on ecological principles. In fact, Spencer Baird, the first appointed Commissioner of the U.S.
Commission of Fish and Fisheries, initiated some of the first ecological-based scientific studies
in the United States during the late 1800s (NMFS, 1998). Even with this fundamental history,
and the requirements of the Sustainable Fisheries Act to manage species according to sustainable
harvest levels, U.S. federal agencies have struggled with applying ecological principles under the
current fishery management process (NMFS, 1996). In many ways, ecological principles have
been “lost in translation” with state and federal agencies primarily focusing research and
management efforts on maximum sustainable yield or other metrics associated with commercial
harvest and economics instead of managing the ecosystem as an interconnected dynamic food-
web considering cumulative direct and indirect impacts. According to King (1995), one of the
key goals in fisheries management includes maximizing yield through weight or revenue, while
maintaining a minimum level of spawning stock. However, using this approach fails to view and
consider the ecosystem as interconnected since managers generally only focus their conservation
and recovery efforts on those species having economic value (commercial and recreational
Government agencies have traditionally funded research and allocated resources for
marine species considered the most economically valuable (Levesque, 2011). State (e.g., Florida,
North Carolina, and Texas) agencies in the United States usually only fund research projects and
programs for species having commercial and recreational (sport fish) value given their funding is
generally associated and driven by taxes on sporting goods (e.g., sport fish restoration) and
fishing license sales. Similar to state agencies, federal agencies usually allocate specific research
funds through programs (e.g., Northeast Consortium, Northeast Cooperative Research Partners
Initiative, Southeast Cooperative Research Program, West Coast Groundfish Cooperative
Research Program, and National Cooperative Research Program) established for commercially
valuable marine species. Although there are many benefits to these types of research programs,
they have limited the development of new fishery management approaches since most of these
funding programs are linked to commercial fisheries, bycatch, life-history biology, or associated
to economics (commercial or recreational fishing) rather than ecological processes (Ruiz and
Roche, 2011) or considering other anthropogenic factors. Research emphasis in the past has been
directed at identifying fisheries resources and best fishing practices through the collection of
relative abundance patterns, catch, effort, size frequency, bycatch, and socioeconomic
information, which has been focused on recreational and commercial fisheries (Ruiz and Roche,
2011). This historical approach to fisheries management practice in the United States and other
regions is beginning to be questioned by the general public and some elected government
officials now that fishing and other anthropogenic activities (climate variability and coastal
development) have been linked to causing cascading effects on the marine ecosystem.
Fisheries management has started to evolve toward a more holistic ecological approach
that includes not only evaluating and assessing multiple species (Lotze et al. (2011), but
developing new analytical tools for predicting and assessing impacts to the marine environment
at large scales (King et al. 2001; Gascuel et al. 2005; Gascuel et al. 2011). Managers are even
starting to consider the impacts associated with climate variability, coastal development, and
other anthropogenic factors (e.g., potential oil spills) affecting populations. However, even with
these recent changes, overall progress has been slow and complicated. There are many reasons
why the ecosystem approach to fisheries (EAF) or EBM has not yet been fully integrated in
fisheries management, but one of the marine reasons has been the lack of scientific studies and
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guidance/policy from fishery organizations on how to apply and integrate this environmental
philosophy and approach into the fishery management process.
In the late 1990s, the Ecosystem Principles Advisory Panel (EPAP) of the United States
was established to report on the status of ecosystem-based fishery management. In their report to
the U.S. Congress, they began their deliberations by asking two simple questions: (1) What are
the effects of fishing on other ecosystem components?” and (2) “What are acceptable standards
for fisheries removals from ecosystems?” According to NMFS (1998), the technical team
indicated the implementation of EBM in the United States was stalled because regional fishery
management councils (FMC) continued to use existing Fishery Management Plans (FMP) for
single species or species complexes, instead of incorporating ecosystem principles that were
consistent with an overall Fisheries Ecosystem Plan. Moreover, the EPAP gave four other
reasons why they believed EBM was missing from the fishery management process in the United
States: (1) having a complete understanding of the ecological system that produced and
supported fishes; (2) the ability to forecast weather or climate and their effects on ecosystems;
(3) being aware that systems evolve over time and understanding how the system works does not
necessarily mean that an ecosystem would respond predictably to future changes in weather,
climate or fisheries; and (4) institutions were not configured to manage at the ecosystem scale.
The EPAP also believed that fish and associated fisheries were not compatible with the current
U.S. political and jurisdictional boundaries, which affected fishery management regulations.
In general, the advisory panel believed that EBM had been lagging in development
because state and federal agencies did not have a clear understanding of what type of ecological
information was necessary and how to use it; there was a lack of direction with specific goals
and objectives (NMFS, 1998). Other reasons the advisory panel indicated why EBM had yet to
be fully implemented in the United States included, but was not limited to a change in fishery
management philosophy (i.e., change the burden of proof; authorizing only those fisheries which
were considered low risk for overfishing), lack of applying risk averse decisions (i.e., error
toward conservation), lack of insurance policies (i.e., mitigation measure for reducing impacts to
the ecosystem from fishing), lack of methods for evaluating management measures on the
ecosystem, lack of incentives that have local and global implications, and lack of fairness and
equity in policy and management (NMFS, 1998).
Among various recommendations from the panel on how to move forward with using an
EBM approach, was for each FMC to develop a fisheries ecosystem plan and with associated
actions. One of the actions the EPAP recommended was for marine resource managers to use
long-term monitoring as a way to evaluate changes in the ecosystem. They indicated that
“changes to the ecosystem cannot be determined without long-term monitoring of biological
indices and climate.” The EPAP stated that long-term monitoring of chemical, physical, and
biological factors would assist with understanding how climate fluctuations could potentially
impact the abundance of commercially important species and their corresponding food webs.
Long-term monitoring programs are among the most important components of the
fisheries management process in the United States. These data can be used to understand how
commercial fisheries, climate fluctuation, and coastal development are shaping the fish
community. Fishery resource managers often rely upon fisheries-dependent (e.g., commercial
landings and sales) and fisheries-independent (e.g., size, age, and weight) data obtained from
long-term monitoring programs for making broad management decisions, but these data are
generally used to evaluate and set commercial fishing limits. Fishery resource managers usually
only have limited data acquired from dependent sources (commercial fishing) to make their
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management decisions since establishing, managing, and funding fisheries-independent
monitoring programs are costly. Although dependent data are important for fisheries
management, data collected from fisheries-independent monitoring programs is invaluable to
fishery researchers and managers charged with protecting, conserving, and recovering marine
resources. Researchers use fisheries-independent monitoring data in a variety of ways, but one of
the key applications is evaluating the population dynamics of local fish communities. Fisheries-
independent monitoring data is also used to identify important fish habitats, which are assessed
by estimating relative abundance and distribution over time (King, 1995; Jennings et al. 2001).
Managers could also use these data to evaluate climate variability and coastal development, but
research progress has been slow.
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