Jorge Cornejo-Donoso

Bio: Jorge Cornejo-Donoso is an academic researcher from University of California, Santa Barbara. The author has contributed to research in topics: Orange roughy & Seamount. The author has an hindex of 7, co-authored 14 publications receiving 271 citations. Previous affiliations of Jorge Cornejo-Donoso include Austral University of Chile.

Eco-Label Conveys Reliable Information on Fish Stock Health to Seafood Consumers

Abstract: Concerns over fishing impacts on marine populations and ecosystems have intensified the need to improve ocean management. One increasingly popular market-based instrument for ecological stewardship is the use of certification and eco-labeling programs to highlight sustainable fisheries with low environmental impacts. The Marine Stewardship Council (MSC) is the most prominent of these programs. Despite widespread discussions about the rigor of the MSC standards, no comprehensive analysis of the performance of MSC-certified fish stocks has yet been conducted. We compared status and abundance trends of 45 certified stocks with those of 179 uncertified stocks, finding that 74% of certified fisheries were above biomass levels that would produce maximum sustainable yield, compared with only 44% of uncertified fisheries. On average, the biomass of certified stocks increased by 46% over the past 10 years, whereas uncertified fisheries increased by just 9%. As part of the MSC process, fisheries initially go through a confidential pre-assessment process. When certified fisheries are compared with those that decline to pursue full certification after pre-assessment, certified stocks had much lower mean exploitation rates (67% of the rate producing maximum sustainable yield vs. 92% for those declining to pursue certification), allowing for more sustainable harvesting and in many cases biomass rebuilding. From a consumer’s point of view this means that MSC-certified seafood is 3–5 times less likely to be subject to harmful fishing than uncertified seafood. Thus, MSC-certification accurately identifies healthy fish stocks and conveys reliable information on stock status to seafood consumers.

Developing seamount fishery produces localized reductions in abundance and changes in species composition of bycatch.

Abstract: Evidence of localized and cumulative impacts of bottom-trawling upon bycatch abundance and diversity was found during the 8-year period the Chilean orange roughy (Hoplostethus atlanticus) fishery was open. We analyzed acoustic, orange roughy catch and fish bycatch data available from a voluntary monitoring program implemented by the fishing-rights holders. Acoustic data, recorded from the third year of the fishery (2002) until its closure in 2006, permitted us to extract detailed bathymetry and precise information about trawl tows. From these data we reconstructed the yearly and cumulative extent of the bottom trawling footprint and compared biodiversity indices, bycatch abundance and assemblage structure between nominally pristine areas and others that exhibited different levels of previous trawling impacts (as measured by within- and across-years impact indices). Although the footprint area expanded as the cumulated number of tows increased, degrees of overlapping between tows were found in all seamounts. The trawled footprint was 22 km 2 for the 2002‐ 2006 period, equivalent to 2.7% of the study area. An extrapolation to include unassigned tows and years without data (1999‐2001) increased this estimate to 81 km 2 (9.8% of the study area) for the entire duration of the fishery. The relative abundance of bycatch species decreased at more heavily impacted areas, suggesting a local depletion response. Evidence of bycatch species richness decline and significant changes in diversity and species assemblage composition were also found at these areas. Seamount management and conservation efforts must consider the cumulative and localized nature of bottom trawling effects we found to occur upon seamount fish communities.

The impacts of deep-sea fisheries on benthic communities: a review

Abstract: Deep-sea fisheries operate globally throughout the world's oceans, chiefly targeting stocks on the upper and mid-continental slope and offshore seamounts. Major commercial fisheries occur, or have occurred, for species such as orange roughy, oreos, cardinalfish, grenadiers and alfonsino. Few deep fisheries have, however, been sustainable, with most deep-sea stocks having undergone rapid and substantial declines. Fishing in the deep sea not only harvests target species but can also cause unintended environmental harm, mostly from operating heavy bottom trawls and, to a lesser extent, bottom longlines. Bottom trawling over hard seabed (common on seamounts) routinely removes most of the benthic fauna, resulting in declines in faunal biodiversity, cover and abundance. Functionally, these impacts translate into loss of biogenic habitat from potentially large areas. Recent studies on longline fisheries show that their impact is much less than from trawl gear, but can still be significant. Benthic taxa, especially the dominant mega-faunal components of deep-sea systems such as corals and sponges, can be highly vulnerable to fishing impacts. Some taxa have natural resilience due to their size, shape, and structure, and some can survive in natural refuges inaccessible to trawls. However, many deep-sea invertebrates are exceptionally long-lived and grow extremely slowly: these biological attributes mean that the recovery capacity of the benthos is highly limited and prolonged, predicted to take decades to centuries after fishing has ceased. The low tolerance and protracted recovery of many deep-sea benthic communities has implications for managing environmental performance of deep-sea fisheries, including that (i) expectations for recovery and restoration of impacted areas may be unrealistic in acceptable time frames, (ii) the high vulnerability of deep-sea fauna makes spatial management—that includes strong and consistent conservation closures—an important priority, and (iii) biodiversity conservation should be > balanced with options for open areas that support sustainable fisheries.; ;

Paradigms in seamount ecology: fact, fiction and future

Abstract: Despite a relatively short history, the field of seamount ecology is rife with ecological paradigms, many of which have already become cemented in the scientific literature and in the minds of advocates for seamount protection. Together, these paradigms have created a widely held view of seamounts as unique environments, hotspots of biodiversity and endemicity, and fragile ecosystems of exceptional ecological worth. However, closer examination reveals significant gaps in our knowledge, thereby calling the accuracy of some of these paradigms into question. Here, we review the evolution of the major paradigms in seamount ecology, assess their status against the weight of existing evidence to date, identify emerging paradigms, and suggest future research directions. We find the assertions that seamount communities are vulnerable to fishing, and that these communities have high sensitivity and low resilience to bottom trawling disturbance are well supported by existing data. We find plausible evidence that seamounts are stepping stones for dispersal, oases of abundance and biomass, and hotspots of species richness. Nonetheless, the poor sampling coverage of these discrete but globally distributed environments prevents us from accepting these ideas as paradigms. Also plausible, but requiring further investigation, are the emerging paradigms that seamount communities are structurally distinct, that populations of invertebrates on seamounts are the source of propagules for nearby slope sinks, and that seamounts have acted and can act as biological refugia from large-scale catastrophic environmental events. In contrast, the generalizations that seamounts are island habitats with highly endemic faunas that comprise unique communities distinct in species composition from other deep-sea habitats, and that they have high production supported by localized bottom-up forcing, are not supported by the weight of existing evidence.

Environmental performance of blue foods

Abstract: Fish and other aquatic foods (blue foods) present an opportunity for more sustainable diets1,2. Yet comprehensive comparison has been limited due to sparse inclusion of blue foods in environmental impact studies3,4 relative to the vast diversity of production5. Here we provide standardized estimates of greenhouse gas, nitrogen, phosphorus, freshwater and land stressors for species groups covering nearly three quarters of global production. We find that across all blue foods, farmed bivalves and seaweeds generate the lowest stressors. Capture fisheries predominantly generate greenhouse gas emissions, with small pelagic fishes generating lower emissions than all fed aquaculture, but flatfish and crustaceans generating the highest. Among farmed finfish and crustaceans, silver and bighead carps have the lowest greenhouse gas, nitrogen and phosphorus emissions, but highest water use, while farmed salmon and trout use the least land and water. Finally, we model intervention scenarios and find improving feed conversion ratios reduces stressors across all fed groups, increasing fish yield reduces land and water use by up to half, and optimizing gears reduces capture fishery emissions by more than half for some groups. Collectively, our analysis identifies high-performing blue foods, highlights opportunities to improve environmental performance, advances data-poor environmental assessments, and informs sustainable diets. A range of environmental stressors are estimated for farmed and wild capture blue foods, including bivalves, seaweed, crustaceans and finfish, with the potential to inform more sustainable diets.

The trophodynamics of marine top predators: Current knowledge, recent advances and challenges

Abstract: We review present understanding of the spatial and temporal diet variability (trophodynamics) of a range of pelagic marine top predators, at both early and adult life history stages. We begin with a review of methodologies used to advance our understanding of the trophodynamics of marine top predators, particularly in relation to climate change. We then explore how these developments are informing our understanding of the major trophic groups in food webs leading to, and including, marine top predators. We examine through specific examples how the impacts of ocean warming may affect pelagic food web relationships from both top-down and bottom-up perspectives. We examine the potential, in the absence of long-term data sets, of using large-scale spatial studies to examine how potential changes in biological oceanography could impact the biomass and composition of prey species, particularly the role of phytoplankton size spectra. We focus on examples from regions where biotic change with respect to climate change is likely. In particular, we detail the effects of climate change on oceanographic and bathymetric "hotspots" and provide the example involving seabirds in the Benguela Current system. We end by urging the development of international collaborations and databases to facilitate comprehensive ocean-scale understanding of climate impacts on marine top predators.

The Weddell Gyre, Southern Ocean: Present Knowledge and Future Challenges

Abstract: The Weddell Gyre (WG) is one of the main oceanographic features of the Southern Ocean south of the Antarctic Circumpolar Current which plays an influential role in global ocean circulation as well as gas exchange with the atmosphere. We review the state‐of‐the art knowledge concerning the WG from an interdisciplinary perspective, uncovering critical aspects needed to understand this system's role in shaping the future evolution of oceanic heat and carbon uptake over the next decades. The main limitations in our knowledge are related to the conditions in this extreme and remote environment, where the polar night, very low air temperatures and presence of sea ice year‐round hamper field and remotely sensed measurements. We highlight the importance of winter and under‐ice conditions in the southern WG, the role that new technology will play to overcome present‐day sampling limitations, the importance of the WG connectivity to the low‐latitude oceans and atmosphere, and the expected intensification of the WG circulation as the westerly winds intensify. Greater international cooperation is needed to define key sampling locations that can be visited by any research vessel in the region. Existing transects sampled since the 1980s along the Prime Meridian and along an East‐West section at ~62°S should be maintained with regularity to provide answers to the relevant questions. This approach will provide long‐term data to determine trends and will improve representation of processes for regional, Antarctic‐wide and global modeling efforts – thereby enhancing predictions of the WG in global ocean circulation and climate.