Overfishing

Author(s):  
Ray Hilborn

This chapter calls into question the veracity of stories, often seen in the scientific literature and popular media, describing the collapse of fish stocks and predicting a soon-to-be-seen dramatic decline in food production from the ocean. In fact, detailed scientific analyses suggest that fish stock abundance is globally stable, and much of the decline in fish catch has been due to more stringent management of fisheries in many countries. This has led to a polarization between those who look at abundance trends, and argue that improving fisheries management is the solution, and those who look at catch and argue that fisheries management does not work and marine protected areas are needed. Data clearly support the effectiveness of fisheries management, whereas remarkably little data demonstrates the impact of marine protected areas outside of the closed areas. This chapter argues the actual impacts of MPAs need to be evaluated much more intensively.

Author(s):  
Ray Hilborn ◽  
Ulrike Hilborn

Over the last 2 decades, the scientific and popular media have been bombarded by gloom-and-doom stories on the future of fisheries, the status of fish stocks, and the impact of fishing on marine ecosystems. Dozens of certification and labeling schemes have emerged to advise consumers on what seafood is sustainable. In recent years, an opposing narrative has emerged emphasizing the success of fisheries management in many places, the increasing abundance of fish stocks in those places, and the prescription for sustainable fisheries. However, there has been no comprehensive survey of what really constitutes sustainability in fisheries, fish stock status, success and failures of management, and consideration of the impacts of fishing on marine ecosystems. This book will explore very different perspectives on sustainability and bring together the data from a large number of studies to show where fish stocks are increasing, where they are declining, the consequences of alternative fisheries management regimes, and what is known about a range of fisheries issues such as the impacts of trawling on marine ecosystems. Aimed principally at a general audience that is already interested in fisheries but seeks both a deeper understanding of what is known about specific issues and an impartial presentation of all of the data rather than selected examples used to justify a particular perspective or agenda. It will also appeal to the scientific community eager to know more about marine fisheries and fishing data, and serve as the basis for graduate seminars on the sustainability of natural resources.


2006 ◽  
Vol 63 (3) ◽  
pp. 642-649 ◽  
Author(s):  
Ray Hilborn ◽  
Fiorenza Micheli ◽  
Giulio A De Leo

Previous models of marine protected areas (MPAs) have generally assumed that there were no existing regulations on catch and have frequently shown that MPAs, by themselves, can be used to maintain both sustainable fish stocks and sustainable harvests. We explore the impact of implementing an MPA in a spatially structured model of a single-species fish stock that is regulated by total allowable catch (TAC). We find that when a stock is managed at maximum sustainable yield, or is overfished, implementation of an MPA will require a reduction in TAC to avoid increased fishing pressure on the stock outside the MPA. In both cases, catches will be lower as a result of overlaying an MPA on existing fisheries management. Only when the stock is so overfished that it is headed towards extinction does an MPA not lead to lower catches. In a TAC-regulated fishery, even if the stock is overfished, MPA implementation may not improve overall stock abundance or increase harvest unless catch is simultaneously reduced in the areas outside the MPA. Models that consider differential adult and larval dispersal need to be explored to see if these results are found with the more complex biology of a two-stage model.


2020 ◽  
Vol 117 (4) ◽  
pp. 2218-2224 ◽  
Author(s):  
Ray Hilborn ◽  
Ricardo Oscar Amoroso ◽  
Christopher M. Anderson ◽  
Julia K. Baum ◽  
Trevor A. Branch ◽  
...  

Marine fish stocks are an important part of the world food system and are particularly important for many of the poorest people of the world. Most existing analyses suggest overfishing is increasing, and there is widespread concern that fish stocks are decreasing throughout most of the world. We assembled trends in abundance and harvest rate of stocks that are scientifically assessed, constituting half of the reported global marine fish catch. For these stocks, on average, abundance is increasing and is at proposed target levels. Compared with regions that are intensively managed, regions with less-developed fisheries management have, on average, 3-fold greater harvest rates and half the abundance as assessed stocks. Available evidence suggests that the regions without assessments of abundance have little fisheries management, and stocks are in poor shape. Increased application of area-appropriate fisheries science recommendations and management tools are still needed for sustaining fisheries in places where they are lacking.


2021 ◽  
Author(s):  
Amanda K. Pettersen ◽  
Ezequiel M. Marzinelli ◽  
Peter Steinberg ◽  
Melinda A. Coleman

2018 ◽  
Author(s):  
Dana Haggarty ◽  
Steve J.D. Martell ◽  
Jonathan B. Shurin

Compliance with spatial fishing regulations (e.g., marine protected areas, fishing closures) is one of the most important, yet rarely measured, determinants of ecological recovery. We used aerial observations of recreational fishing events from creel surveys before, during, and after 77 Rockfish Conservation Areas (RCAs) were established in British Columbia, Canada. There was no evidence of a change in fishing effort in 83% of the RCAs, and effort in five RCAs increased after establishment. Fishing effort in open areas adjacent to the RCAs declined with time and was higher than effort in the RCAs in all 3 years. Next, we used compliance data for 105 RCAs around Vancouver Island to model the drivers of compliance. Compliance was related to the level of fishing effort around the RCA, the size and perimeter-to-area ratio of RCAs, proximity to fishing lodges, and the level of enforcement. Noncompliance in RCAs may be hampering their effectiveness and impeding rockfish recovery. Education and enforcement efforts to reduce fishing effort inside protected areas are critical to the recovery of depleted fish stocks.


2019 ◽  
Vol 179 ◽  
pp. 104831 ◽  
Author(s):  
Richard N. Muallil ◽  
Melchor R. Deocadez ◽  
Renmar Jun S. Martinez ◽  
Wilfredo L. Campos ◽  
Samuel S. Mamauag ◽  
...  

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Antonio Di Franco ◽  
Pierre Thiriet ◽  
Giuseppe Di Carlo ◽  
Charalampos Dimitriadis ◽  
Patrice Francour ◽  
...  

2016 ◽  
Vol 73 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Outi Heikinheimo ◽  
Pekka Rusanen ◽  
Katja Korhonen

Estimates of the mortality rates caused by cormorants are needed to assess the impact on fish stock dynamics and fisheries. In this study, we calculated the annual instantaneous mortality caused by great cormorants (Phalacrocorax carbo sinensis) on young pikeperch (Sander lucioperca), using data from Archipelago Sea, southwestern coast of Finland. The pikeperch are vulnerable to cormorant predation mainly at the ages 2–4. The annual instantaneous mortality caused by cormorants was between 0.04 and 0.13, and the estimated effect on the pikeperch stock size at recruitment to the fishery ranged from 4% to 23%, respectively. The average annual cormorant-induced mortality accounted for 5%–34% of the total mortality in these age groups. The sensitivity analyses proved that the rates of mortality from other sources largely affect the estimated mortality from cormorant predation. In cases with strong fluctuations in the abundance of the prey fish stocks, ignoring the size and density dependence of the natural mortality may lead to overestimation of the importance of cormorants as competitors of fisheries.


2006 ◽  
Vol 69 (sc) ◽  
pp. 66-78 ◽  
Author(s):  
G. Stefansson*† ◽  
A. A. Rosenberg

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