Fisheries Management

Overfishing and the Replacement of Demersal Finfish by Shellfish: An Example from the English Channel

Filed under: Fisheries Management, Projects 

Note: this research, and other similar findings, illustrate the fact that fish stocks do not exist in isolation, thus emphasizing the importance of an ecosystem approach to fisheries management.

July 10th, 2014, by Carlotta Molfeese, Doug Beare, Jason M. Hall-Spencer, Research Article on PLOSone.org

Abstract

The worldwide depletion of major fish stocks through intensive industrial fishing is thought to have profoundly altered the trophic structure of marine ecosystems. Here we assess changes in the trophic structure of the English Channel marine ecosystem using a 90-year time-series (1920–2010) of commercial fishery landings. Our analysis was based on estimates of the mean trophic level (mTL) of annual landings and the Fishing-in-Balance index (FiB). Food webs of the Channel ecosystem have been altered, as shown by a significant decline in the mTL of fishery landings whilst increases in the FiB index suggest increased fishing effort and fishery expansion. Large, high trophic level species (e.g. spurdog, cod, ling) have been increasingly replaced by smaller, low trophic level fish (e.g. small spotted catsharks) and invertebrates (e.g. scallops, crabs and lobster). Declining trophic levels in fisheries catches have occurred worldwide, with fish catches progressively being replaced by invertebrates. We argue that a network of fisheries closures would help rebalance the trophic status of the Channel and allow regeneration of marine ecosystems.

Introduction

Effects of overfishing on marine trophic structure

The field of historical marine ecology has introduced a different perspective to our understanding of marine ecosystems; it has revealed that overfishing has had profound effects on coastal ecosystems worldwide for centuries [1][2]. The historical response to overfishing is an increase in fishing effort, an expansion to new and deeper grounds and a shift to new target species [3]. In the last decade, fisheries have shifted towards smaller, lower-trophic level species as large predatory species with a higher economic value had been depleted [4]. This phenomenon, known as “fishing down marine food webs” was first described by [5] in 1998: they demonstrated a decline in the trophic level of global fisheries landings from 3.3 units in the early 1950s to 3.1 in 1994. Studies performed independently from commercial catch data on smaller, regional scales over the last decades have shown even more rapid declines in trophic level.

Fisheries typically remove top predators first and as a result their direct competitors and prey are able to prosper, affecting the overall productivity and ecological stability of the ecosystem[1]. Severe declines in the populations of major predator species have now been reported around the world [6][7]. Overexploitation of a species can have cascading effects and have the potential to trigger regime shifts altering the ecological function of marine systems [8][9]. In many instances, the decline of finfish species has been followed by an increase in their invertebrate prey [10][11] and although new and economically viable fisheries have developed for these new target species, concerns have been raised about their long-term sustainability as well as shifts towards homogenized, simplified ecosystems [12][13].

In the present study, we used a 90-year dataset of international catch statistics from the English Channel marine ecosystem, a region that has numerous important fishing ports and where finfish landings now make up a far smaller proportion of the catch than they did historically (Figure 1). This dataset spans a period of intensive fishing which we use to assess whether there has been a trend for ‘fishing down’ food webs in a region where it has not been reported before. Finally, we discuss the way forwards to improve fisheries sustainability using area closures to aid recovery of marine ecosystems.

Read more of the research article here

Several mainstream media sources covered this research: The Telegraph, Western Morning News, and The Plymouth Herald

“More fish in the sea” is not a reason to keep overfishing

Filed under: Fisheries Management 

Yum. Bristlemouth. Photo courtesy of NOAA

March 12th, 2014, by Amelia Urry on Grist.org

Bristlemouth à la beurre. Miso-seared mola mola. Lanternfish tartare.

If you’ve never seen these things on a menu, that’s probably because humans don’t generally catch or eat the denizens of the mesopelagic zone, that slice of sea about 656 to 3,280 feet below the ocean surface (also known as 200 to 1000 meters, which is much easier to remember). Lying just below the pelagic, the top layer of the open sea where most of the fish we’re familiar with live, the mesopelagic is apparently much more lively than we thought.

paper published last month in the journal Nature Communications revised the estimate of biomass in this “twilight zone” of the ocean up from 1 billion tons to more than 10 billion — meaning these deep-dwellers actually make up something like 95 percent of the total fish in the sea.

This might sound like good news — lots more fish! — but it’s not nearly as good as some news outlets would have you believe. The right-wing blog Powerline optimistically asserted that “maybe overfishing of tuna won’t turn out to be quite the crisis we thought it was,” while The National Review’s Greg Pollowitz told us to stop worrying about ocean pollution since deep-water “deserts” under trash gyres turn out to be chock-full of fish. Even Popular Science overplayed the positive angle in its subhead: “Good news for fish. And humans who like fish.” (To be fair, a caveat followed in the piece itself: “This study doesn’t have much relevance for the issue of overfishing, which is an enormous and still growing problem.”)

I like fish, but I don’t expect to be picking dragonfish bones out of my teeth anytime soon. Deep-sea biologist Andrew David Thaler points out that media coverage of this study has distinctly neglected context — namely that, while this news teaches us a lot about the mechanics of the open ocean food chain, and may even explain why the sea is so good at absorbing our extra carbon, it really has little to bring to the human dinner table. Yes, there are a lot of (weird) fish out there, but that’s not a good excuse to keep dumping plastic in the Pacific or fishing bluefin tuna to extinction.

Not to mention that mesopelagic fish have been undercounted precisely because they are extraordinarily good at evading the trawl nets sent down to survey them. (So don’t get too excited about plundering this untapped food source, at least not yet.) The new research was done with sonar instead — harder to dodge that sound wave, huh, myctophids?

Read more here

What are We Protecting? Fisher Behavior and the Unintended Consequences of Spatial Closures as a Fishery Management Tool

Economists Alan Haynie (Economics & Social Sciences Research (ESSR) program) and Joshua Abbott (Arizona State University) have a forthcoming publication in the journal Ecological Applications that examines the impacts of the red king crab savings area (RKCSA) on the Bering Sea flatfish fishery.

Specifically, the paper examines the winter rock sole and Pacific cod fishery in the years immediatedly following the creation of the RKCSA in 1995. Spatial closures like marine protected areas (MPAs) are prominent tools for ecosystem-based management in fisheries. However, the adaptive behavior of fishermen (the apex predator in the ecosystem) to MPAs may upset the balance of fishing impacts across species.

While ecosystem-based management (EBM) emphasizes the protection of all species in the environment, the weakest stock often dominates management attention. We use data before and after the implementation of the RKCSA to show how closures designed for red king crab protection spurred dramatic increases in Pacific halibut bycatch due to both direct displacement effects and indirect effects from adaptations in fishermen’s targeting behavior. We identify aspects of the ecological and economic context of the fishery that contributed to these surprising behaviors, noting that many multispecies fisheries are likely to share these features.

Our results highlight the need to either anticipate the behavioral adaptations of fishermen across multiple species in reserve design, a form of implementation error, or to design management systems that are robust to these adaptations. Failure to do so may yield patterns of fishing effort and mortality that undermine the broader objectives of multispecies management and potentially alter ecosystems in profound ways.

By Alan Haynie

Thousands of Coastal Fishermen to Rally in DC on March 21

In another historic show of solidarity, US recreational and commercial fishermen will gather at Upper Senate Park in Washington DC on March 21, 2012 starting at noon in an organized demonstration supporting sensible reform of the Magnuson Stevens Fisheries Conservation and Management Act.

This is a follow-up to a rally in February of 2010 that brought some 5,000 recreational, commercial and party/charter vessel owners, fishermen and people in fisheries dependent businesses from all over the country to Washington. Twenty plus Members of the Senate and House of Representatives spoke regarding efforts to reform Magnuson.

Click here to read more

Pribilof Islands Collaborative

NFCC helped plan and then facilitated the ongoing work of the Pribilof Islands Collaborative (PIC), a cooperative effort that included the representatives from the two islands, major fishing industry sectors (e.g., pollock, crab, longliners), and conservation groups (e.g., The Nature Conservancy, World Wildlife Fund). PIC’s goal was to create opportunities to share scientific and technical information, build relationships both within and across interest groups, and identify collaborative efforts that would improve knowledge and sustain resources. PIC focused separate meetings on fur seals, seabirds, crab and halibut, climate change, and economic development. The January 2005 workshop on fur seal ecology included presentations from all the leading fur seal researchers and resulted in a prioritized list of research needs that influenced NOAA’s funding decisions.

See the presentation materials

Steller Sea Lion Recovery Plan

Filed under: Fisheries Management, Projects 

NFCC facilitated the final two meetings of the Steller Sea Lion Recovery Team, in Homer, AK and Seattle, WA, in 2005. NFCC’s efforts succeeded in helping the Recovery Team complete a consensus draft of an updated recovery plan within the deadline set by NOAA.

Pollock MSC Certification Issues

Filed under: Fisheries Management, Projects 

NFCC completed a shadow evaluation of the Alaska pollock fishery’s performance on the Marine Stewardship Council’s certification criteria to better inform the World Wildlife Fund’s participation in the certification process. The evaluation team included experts in marine ecosystems, stock assessment, and fisheries management. The evaluation summarized the main ecological, scientific, and management issues; scored the fishery on each of the certification criteria; and made specific recommendations about how the fishery could improve its performance

Read the full report here: Pollock Certification Report

Using Decision Analysis in Fisheries

Filed under: Fisheries Management, Projects 

With support from the David and Lucile Packard Foundation, NFCC conducted two two-day hands-on workshops in the application of decision analysis to fisheries stock assessment and management. The workshops, which combined presentations by experts in decision analysis with problem-solving applications, provided fisheries scientists, managers, and advocates an opportunity to better understand the potential value of this tool, particularly in handling the uncertainty inherent in fisheries.

NMFS Performance Audit

Filed under: Fisheries Management, Projects 

NFCC conducted a confidential audit of the utility and management of NMFS’ decision-making process, with a particular focus on the agency’s ability to comply with legal mandates provided by the National Environmental Policy Act (NEPA), the Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA), the Endangered Species Act (ESA), and the Regulatory Flexibility Act (RFA). NFCC conducted a large number of confidential interviews with NOAA/NMFS personnel, both at headquarters an in the regions, as well as with representatives of various industry groups and advocacy organizations. NFCC presented its findings and recommendations in an executive briefing at NMFS headquarters that included presentations from high-level managers at other federal agencies that had successfully resolved problems similar to those NMFS was confronting. NFCC then facilitated a series of workshops with staff from the regional fishery management councils to develop implementation plans for the recommendations resulting from the audit.

Identifying Fisheries Research Needs

Filed under: Fisheries Management, Projects 

NFCC supported the Sloan Foundation’s initial planning efforts for a Census of the Fishes, which evolved into the Census of Marine Life, by reviewing a wide range of fishery council stock assessments and planning documents to extract region- and species-specific research and data needs. This information contributed to the Sloan Foundation’s assessment of the needed scope of the Census.

Read the full report here: Sloan Research Needs in Fisheries Final Report

 

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