Historical overfishing and the recent collapse of coastal ecosystems

Bates College, Льюистон, Maine, United States
Science (Impact Factor: 33.61). 08/2001; 293(5530):629-37. DOI: 10.1126/science.1059199
Source: PubMed

ABSTRACT Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including
pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species
were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show
that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities,
because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished
or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates
of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that
could not even be contemplated based on the limited perspective of recent observations alone.

Download full-text


Available from: J. M. Pandolfi, Sep 26, 2015
1 Follower
192 Reads
  • Source
    • "Crain et al., 2008; Sala et al., 2000). With growing human population comes an increase in the diversity and intensity of anthropogenic stressors (Halpern et al., 2007) including habitat loss, over-exploitation of key species (Jackson et al., 2001) pollution (particularly excess nitrogen), invasive species and more recently climate change (Kappel, 2005; Sala et al., 2000; Venter et al., 2006; Wilcove et al., 1998). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Increasing population pressure, urbanization of the coastal zone and nutrient and sediment run-off from agriculture and forestry has increased the number of large-scale and chronic impacts affecting coastal and estuarine systems. The need to assess cumulative impacts is a major motivation for the current desire of managers and ecologists to define ecosystem “health” and “stress”. A number of univariate metrics have been proposed to monitor health, including indicator species, indicator ratios and diversity or contaminant metrics. Alternatively, multivariate methods can be used to test for changes in community structure due to stress. In this study we developed Multivariate Models using statistical ordination techniques to identify key stressors affecting the ‘health’ of estuarine macrofaunal communities. Macrofaunal and associated environmental samples were collected across 75 sites from within Tauranga Harbour, a large estuary located on New Zealand’s North Island. The harbour receives discharges from urbanized, industrial, agricultural and horticultural catchments. Distance-based linear modelling identified sediments, nutrients and heavy metals as key ‘stressors’ affecting the ecology of the harbour. Therefore, three multivariate models were developed based on the variability in community composition using canonical analysis of principal coordinates (CAP). The multivariate models were found to be more sensitive to changing environmental health than simple univariate measures (abundance, species richness, evenness and Shannon-Wiener diversity) along an anthropogenic stress gradient. This multivariate approach can be used as a management or monitoring tool where sites are repeatedly sampled over time and tracked to determine whether the communities are moving towards a more healthy or unhealthy state. Ultimately, such statistical models provide a tool to forecast the distribution and abundance of species associated with habitat change and should enable long term degradative change from multiple disturbances to be assessed.
    Journal of Experimental Marine Biology and Ecology 12/2015; 473. DOI:10.1016/j.jembe.2015.09.003 · 1.87 Impact Factor
  • Source
    • "mammals and birds) extinctions in several continents , beginning around 15 000 years ago (Turvey, 2009; Prescott et al., 2012). A similar pattern of depletion and extinction is seen in the world's ocean megafauna (Jackson et al., 2001; Lotze et al., 2006) where a variety of taxa, including sharks, rays, large teleost fishes, sea turtles, sea birds and marine mammals, declined to extremely low levels during the last century mainly because of direct exploitation and/or incidental bycatch (Myers & Worm, 2003; Lewison et al., 2004). Similar to the long-lived giant terrestrial beasts of the Pleistocene, the marine megafauna of today are declining largely as a result of human's improved efficiency and expansion of fishing (Heppell et al., 2005). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Increasing exploitation effort and efficiency have been leading to population declines and extinctions among large marine animals. Understanding the magnitude of such losses is challenging because current baselines about species’ abundances and distributions in the sea were mostly established after humans had started affecting marine populations. For artisanal fisheries, from which written historical records are rarely, if ever, available, approaches based on gathering anecdotal information from fishers’ knowledge are a promising method to know past environmental conditions. We interviewed coastal artisanal fishers, with ages varying from 15 to 85 years, to detect temporal changes in the catch abundance of large fish species, particularly the largetooth sawfish, Pristis pristis, and the goliath grouper, Epinephelus itajara, within Abrolhos Bank, Brazil. Most fishers considered that fishing has led to species depletion. However, older fishers reported significantly more species and larger species as depleted than young fishers. Older fishers caught significantly larger smalltooth sawfish and goliath grouper in the past than younger fishers. The largetooth sawfish has not been caught or sought for more than ten years. Probabilistic tests provided no definitive evidence for local extinction, although the past record of sightings indicates a population decline close to the threshold level for extinction probability. We provide evidence that small-scale artisanal fisheries can decimate the abundance of large coastal fishes, one of those almost to local extinction. Finally, our results suggest that the younger generation is not aware of past ecological conditions, indicating the occurrence of a shifting baseline syndrome among the fishing community.
    Animal Conservation 12/2015; 18:348-258. DOI:10.1111/acv.12178 · 2.85 Impact Factor
  • Source
    • "Oceanographic conditions that facilitate the highest abundance of loggerhead turtles on the surface are found during the summer months in this area (Hawkes et al., 2007; Mansfield et al., 2009) which overlaps with the sea scallop fishery. This under-sampled site is important for large immature and adult loggerheads (Mansfield et al., 2009)aswell as a central location for multiple globally valuable commercial fisheries (Jackson et al., 2001). Here, immature loggerhead interactions with commercial fishing activities are known to occur (Murray, 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: This study represents the first documented use of a remotely operated vehicle (ROV) to actively track sea turtles in situ. From 2008 to 2014, an ROV was deployed to track the at-sea behavior of loggerhead turtles in the Northwest Atlantic Ocean. Seventy turtles were tracked, totaling 44.7 h of direct turtle footage. For all attempts, usable video with a turtle retained in view for a minimum of 30 s, was produced at a rate of 43.5% of effort. Turtles were first spotted from the boat, and then when the turtle was within ~ 50 m of the boat, the ROV was deployed to track the turtle for as long as possible. Tracking durations reached up to 426.1 min. Tracked turtles often remained within ~ 10 m of the surface; however loggerheads were tracked to the seafloor on 12 occasions. Turtles were filmed foraging both pelagically and benthically, even though bottom temperatures reached as low as 7.1 °C. A range of inter- and intra-species interactions were also captured. Several varieties of fish remained associated with individual turtles for extended periods of time, even during benthic foraging dives. Additionally, a variety of social interactions between loggerheads were documented. Generally these interactions were filmed occurring near the ocean surface. Overall, using the ROV provided great insight into loggerhead at-sea behavior, otherwise unattainable using previously established techniques.
    Journal of Experimental Marine Biology and Ecology 10/2015; 471. DOI:10.1016/j.jembe.2015.05.016 · 1.87 Impact Factor
Show more