An artisanal shrimp trawl fishery operating illegally in northern Peru has high levels of bycatch and three main commercial species. Here we provide the first characterisation of the socio-economic contribution of this fishery. Estimates have been generated for the capital values, operational and maintenance costs, as well as net profits at point of landing and across the value chain. This fleet sector in northern Peru is estimated at 105 vessels, generating an annual gross income of U$D 4.8 million with 315 direct jobs. Vessel owners could potentially have a net income of over ∼$12,000 per year, and crew are likely to be earning 45 % above the living wage for similar land-based rural employment, including other fishing activities operating in the same areas. With an appropriate multiplier for the seafood supply chain, the gross economic value of the fishery from landings up to the retail level is estimated at U$D 35 million with 915 jobs. Recommendations for improving the sustainability of the fishery and possible mitigations are discussed to address the gulf between policy and regulatory intent and reality, where enforcement is lacking or absent.

Increasing competition for marine space requires the appropriate development of indicators to best represent the use of marine areas and the value (whether economic, social and/or cultural) derived from such use. Fishers (the largest group of users) are often under-represented in marine spatial planning processes. Highly-resolved vessel tracking data provide opportunities to map the activities of fishing vessels at a level of detail never before available. Most effort mapping methods have focused on active gears such as trawls or dredges in large scale fisheries. For these fisheries, the time spent fishing at sea (hours) is usually a representative indicator of fishing effort, enabling a straightforward mapping of the most important fishing grounds. However, for passive gears generally used in small-scale fisheries, we show that spatial indicators of effort (here, length of vessel track) greatly outperform time-at-sea as an indicator of fishing effort. We further demonstrate and validate a method to estimate gear soak time from vessel tracking data and show how maps of effort that account for soak time can be different from those solely based on time spent fishing at sea. The development of adequate methods to quantify the spatial distribution of passive gear effort is particularly relevant to fisheries management because globally about a fifth of all catches (by weight) are landed by passive gears. Appropriate, fine scale effort maps will provide better tools for spatial planning to support sustainable fishing.

Around 4.2 million tonnes of fish and other species, some of which are of conservation concern, are discarded every year in bottom trawl fisheries. This study focusses on a small-scale shrimp trawl fishery located in northern Peru that operates with high level of discards which causes conflict with other local fishers. Despite trawling being an illegal activity within the 5NM off the coast, this fishery has been operating in these inshore areas for over 40 years because it sustains the well-being of hundreds of fishers. This study aimed to identify the factors that affect the spatio-temporal variation in catches in order to propose recommendations that can be adopted by fishers to minimise their impact on the ecosystem while still providing economic opportunities. The spatial distributions of shrimp, main commercial species and discards were modelled over time using hierarchical generalised additive models. Strong spatio-temporal variation was observed for all catch components and moon phase affected commercial species and discards differently. The results show that, to reduce the environmental impacts of this fishery in the short-term, the fishing area could be divided into north and south and that fishing activities should be limited to the southern area in the autumn. Other recommendations rely on temporal closures during the week of the first quarter of the moon phase. Finally, considering the institutional weaknesses in monitoring, control and surveillance, we suggest that the only realistic approach to reduce the fishery's environmental impacts in the short-term is to foster the willingness of fishers to adopt responsible fishing practices. Yet, long-term solutions will require comprehensive co-management efforts.

About a third of all marine fish in the world are caught in Small-Scale Fisheries (SSF). SSF are increasingly recognised as essential for food security and livelihoods for vulnerable and economically fragile communities globally. Although individual SSF vessels are usually perceived as having little impact on the ecosystem, the cumulative impact of gear type and number of vessels may be substantial. Bottom trawling is a common fishing method that can greatly influence the marine ecosystem by damaging the seafloor and generating high levels of discards. However, appropriate sampling coverage using on-board observer programmes to collect these data from SSF are rare, as they are expensive and pose logistical constraints. A mobile App was used to assess whether self-reporting by fishers could provide reliable fine-scale information on fishing effort and discards over time in an illegal shrimp trawling fishery in northern Peru. Maps depicting the spatial distribution of trawling effort and the proportion of discards from observers and fishers were compared using the Similarity in Means (SIM) Index, which ranges from 0 when spatial patterns differ completely to 1 when spatial patterns are very similar. High levels of agreement between spatio-temporal patterns of effort (SIM Index = 0.81) and discards (0.96) were found between fisher and observer maps. Moreover, far greater spatial coverage was accomplished by fishers, suggesting that self-reporting via an App represents a useful approach to collect reliable fisheries data as an initial step for effective monitoring and management of these fisheries.

All aspects of fish supply chains have been severely affected by the COVID-19 pandemic, with jobs, income and food security at risk. In Peru, small scale fisheries are fundamental for food security, contributing to about 2/3 of all fish consumed nationally. One of the most important resources which is more affordable for local and regional consumption is hake (Merluccius gayi peruanus). This study is a first attempt to describe the small-scale hake fishery value chain and to quantify the impact of COVID-19 from March to August 2020 in two fishing communities in northern Peru. The levels of fishing and primary buying were the most affected, and we estimate that 23,000 fishing trips were not conducted, 1680 t of hake was not landed (83% decrease), and 620 jobs were negatively impacted during this period. The gross income of vessel owners and primary buyers decreased by $US 913,000. Marked differences were observed in the way each community responded to the pandemic and in their resilience to cope with COVID-19, despite being located less than 10 km away. In El N similar to uro, which relied more heavily on the international market for hake trade, the value chain was affected for longer, while in Los ' Organos which supplied national markets, the chain was restored after an initial period of adjustment. Our study suggests that government efforts should focus on facilitating a formalisation process in all levels of the chain, develop indicators to monitor the resumption of activities and the inclusion of a value chain approach to smallscale fisheries management.

Bivalve aquaculture production takes place in many coastal ecosystems, providing livelihood to thousands of people. Knowledge on the ecological carrying capacity (ECC) of an ecosystem under the impact of such cultures is crucial for long-term sustainability, since overstocking of culture combined with critical environmental changes may result in bivalve mass mortalities and may ultimately cause severe consequences for the entire ecosystem. As yet, most approaches have focussed on bivalve-food (phytoplankton) interactions, neither considering the interaction with other species, nor the overall impact on the ecosystem. The present study follows a holistic approach to estimate the ECC for a bay system in Northern Peru which has recently developed into a hotspot for scallop ( Argopecten purpuratus ) bottom culture. Using a trophic food web model, the further expansion of culture activities is explored by forcing scallop biomass to increase to 4 different levels (458, 829, 1200, and 1572 t km -2 ) and the impact on other groups and the ecosystem are investigated. The ecological carrying capacity (ECC) is defined as the maximum amount of scallop biomass that would not yet cause any other group’s biomass to fall below 10% of its original biomass. Results suggest that a) the current magnitude of scallop bottom culture (147.4 t km -2 ) does not yet exceed ECC, b) phytoplankton availability does not represent a critical factor for culture expansion, c) a further increase in scallop biomass may cause scallop predator biomasses to increase, representing in turn a top-down control on other groups of the system, and d) exceeding scallop biomass levels of 458 t km -2 may cause other functional groups biomasses to fall below the 10% threshold. The results of this work are expected to aid management of coastal ecosystems exposed to bivalve bottom culture by providing ecosystem-based estimates of ECC, defined as the maximum degree of tolerable change, in order to ensure the long-term sustainable use of these valuable marine resources.

Aquaculture has become an important factor to support global fisheries in achieving sustainable levels for overexploited natural stocks. The Peruvian scallop Argopecten purpuratus represents one of the economically most important cultivated molluscs along the South American Pacific coast, with a major cultivation spot in Sechura Bay, Peru. Here, the species is grown in bottom cultures, and the intensity and area extent of the cultivation activities have continuously increased over the last years. About 2500 artisanal fishers and 20000 additional personnel are currently involved in the scallop production chain, and with an annual export value of 158mill.US$ (in 2013) the activity represents an important socioeconomic sector for the region. As overstocking, especially combined with critical environmental changes may lead to scallop mass mortalities and may ultimately cause severe impacts on the entire ecosystem, the understanding of already imposed changes is crucial for the identification of long-term sustainable levels. The introduction of large scallop biomass quantities may change the benthic community structure by providing settling substrate for hard-bottom fauna in an initially soft-bottom habitat. An interdisciplinary study (SASCA) initiated in 2013 aims at the determination of the bay’s carrying capacity – the maximum amount of cultivated organisms that a system can support without causing unacceptable impacts on the system itself – with regard to the physical, production, ecological and social dimension. Several ecological and ecophysiological experiments were conducted to investigate the impact of scallop bottom culture on the benthic and infaunal community, as well as the respiratory demands and optimum growth of scallops. The systemic impact of scallop culture was evaluated using trophic modelling, and different modelling approaches were combined for the estimation of carrying capacity. Data from a socio-economic survey were integrated to explore the response of the system under different environmental conditions and culture scenarios. The here presented project aims at contributing to the on-going research on the estimation of carrying capacity for coastal systems exposed to bivalve aquaculture enterprises through a holistic research approach. The results are expected to help guiding the governance of Sechura bay and may also be relevant for other coastal systems exposed to aquaculture.

To a certain degree, Eastern Boundary Current (EBC) ecosystems are similar: Cold bottom water from moderate depths, rich in nutrients, is transported to the euphotic zone by a combination of trade winds, Coriolis force and Ekman transport. The resultant high primary production fuels a rich secondary production in the upper pelagic and nearshore zones, but where O2 exchange is restricted, it creates oxygen minimum zones (OMZs) at shelf and upper slope (Humboldt and Benguela Current) or slope depths (California Current). These hypoxic zones host a specifically adapted, small macro- and meiofauna together with giant sulphur bacteria that use nitrate to oxydise H2S. In all EBC, small polychaetes, large nematodes and other opportunistic benthic species have adapted to the hypoxic conditions and co-exist with sulphur bacteria, which seem to be particularly dominant off Peru and Chile. However, a massive reduction of macrobenthos occurs in the core of the OMZ. In the Humboldt Current area the OMZ ranges between <100 and about 600 m, with decreasing thickness in a poleward direction. The OMZ merges into better oxygenated zones towards the deep sea, where large cold-water mega- and macrofauna occupy a dominant role as in the nearshore strip. The Benguela Current OMZ has a similar upper limit but remains shallower. It also hosts giant sulphur bacteria but little is known about the benthic fauna. However, sulphur eruptions and intense hypoxia might preclude the coexistence of significant mega- und macrobenthos. Conversely, off North America the upper limit of the OMZ is considerably deeper (e.g., 500–600 m off California and Oregon), and the lower boundary may exceed 1000m. The properties described are valid for very cold and cold (La Niña and "normal") ENSO conditions with effective upwelling of nutrient-rich bottom water. During warm (El Niño) episodes, warm water masses of low oxygen concentration from oceanic and equatorial regions enter the upwelling zones, bringing a variety of (sub)tropical immigrants. The autochthonous benthic fauna emigrates to deeper water or poleward, or suffers mortality. However, some local macrofaunal species experience important population proliferations, presumably due to improved oxygenation (in the southern hemisphere), higher temperature tolerance, reduced competition or the capability to use different food. Both these negative and positive effects of El Niño influence local artisanal fisheries and the livelihood of coastal populations. In the Humboldt Current system the hypoxic seafloor at outer shelf depths receives important flushing from the equatorial zone, causing havoc on the sulphur bacteria mats and immediate recolonisation of the sediments by mega- and macrofauna. Conversely, off California, the intruding equatorial water masses appear to have lower oxygen than ambient waters, and may cause oxygen deficiency at upper slope depths. Effects of this change have not been studied in detail, although shrimp and other taxa appear to alter their distribution on the continental margin. Other properties and reactions of the two Pacific EBC benthic ecosystems to El Niño seem to differ, too, as does the overall impact of major episodes (e.g., 1982/1983(1984) vs. 1997/1998). The relation of the "Benguela Niño" to ENSO seems unclear although many Pacific-Atlantic ocean and atmosphere teleconnections have been described. Warm, low-oxygen equatorial water seems to be transported into the upwelling area by similar mechanisms as in the Pacific, but most major impacts on the eukaryotic biota obviously come from other, independent perturbations such as an extreme eutrophication of the sediments ensuing in sulphidic eruptions and toxic algal blooms. Similarities and differences of the Humboldt and California Current benthic ecosystems are discussed with particular reference to ENSO impacts since 1972/73. Where there are data available, the authors include the Benguela Current ecosystem as another important, non-Pacific EBC, which also suffers from the effects of hypoxia.

1. This study is the first attempt using Levins's Theory (loop analysis) in order to develop a sustainable management for the scallop. Argopecten purparatus, fishery in Peru during El Nino-Southern Oscillation events (ENSO) and upwelling conditions. Based on this theoretical framework, it was possible to estimate the local stability for each of these model systems and to follow the qualitative changes of the variables in response to external factors:2. Based on our results, we suggest the following management policies to be implemented: (1) during ENSO events the size at the first capture of the scallops should be >70 mm and (2) the increase in the number of fishermen during ENSO events must be prevented. Both measures increase the sustainability of fishery under ENSO and upwelling conditions. The ecological models predict that during ENSO and upwelling events, any management strategy to increase the recruitment of the scallop would not have a positive impact on the adult stock.3. Finally, we suggest that more efforts must be focused on the development of extended ecosocial models, which incorporate further social and economic variables, increasing realism of the abstractions for this fishery activity. Copyright (C) 2002 John Wiley Sons, Ltd.

1. This paper sets out to: (1) review previous ecological studies and analyse recent trends of the Peruvian bay scallop fishery in order to better understand and to model the species’ temporal and spatial (meta) population dynamics along the South Pacific coast; (2) develop a fisheries model to protect the stock from overexploitation and optimize the annual yield of the pulse fishery in Independence Bay, the centre of the scallop diving fishery in Peru. 2. Natural stock fluctuations are very pronounced in this species and are positively correlated with the El Niño–Southern Oscillation (ENSO). During such an event, habitat conditions for the Peruvian bay scallop are improved either regionally or locally, such that populations proliferate and larval production and dispersal are greatly increased. Extinct beds and new habitats are recolonized during these periods (producing a strong pulse of metapopulation biomass), although most become extinct very shortly thereafter. 3. For management purposes, two considerations are fundamental: (1) heavy overfishing or extinction of the main scallop source populations would endanger the metapopulation as a whole; (2) rates of growth and survival greatly increase (and with them the potential yield of the scallop stock) locally over an El Niño cycle in a way that can be roughly estimated from past experience, including the most recent El Niño event (1997–1998). 4. We suggest a fisheries management regime capable of adapting to natural changes and propose a procedure for calculating both the optimal yield and the respective fishing effort under normal upwelling and El Niño scenarios, considering changes in the size at first capture (Lc) and fishery mortality (F). Copyright © 2000 John Wiley & Sons, Ltd.

Von Bertalanffy growth parameters of the Peruvian scallop (Argopecten purpuratus) from Peru were derived from (1) a growth experiment with suspended scallops near Independence Island (September 1987 - September 1988); (2) monthly length frequencies from a natural scallops bank at Tunga, Independence Bay (September 1987 - March 1988); (3) length frequencies data from scallops collected in Atenas (Paracas Bay) during the El Nino event 1982-1983.The growth parameters obtained using a Gulland and Holt plot for the suspended scallops were K = 2.25 year-1 and L(infinity) = 94.3 mm. The analysis of the length frequencies data yielded K and L(infinity) of 0.565 year-1 and 110 mm for the Tunga data and 2.9 year-1 and 112.0 mm for the Atenas data, respectively.The growth performance index phi' (phi' = log K + 21 og L(infinity)) was highest for scallops from Atenas (4.56) followed by those from Independence Island (4.30) and Tunga (3.83). Our results indicate that the suspended scallops from Independence Island (1987-1988) grew to a similar length to those on the bottom in Atenas during the 1982-1983 El Nino phenomenon, whereas the growth of the scallops on the bottom at Tunga was significantly inferior.

A brief description of the NMFS/ORSTOM/ICLARMClimate and Eastern Ocean Systems (CEOS) project is given. CEOS will study the four major eastern boundary current regions (Peru/Chile, California, Northwest and Southwest Africa) and attempt to separatelocal short­ term changes of their resources and/or dynamics from long-term, climatic global changes.. Expected products range from a large, widely accessible oceanographic/atmosphericdatabase to various documents that will present key results as well as improved contacts and stronger analytical capabilities in cooPeJ:ating national institutions.

Journal of Fish BiologyVolume 33, Issue 5 p. 815-817 Indirect estimation of oxygen and food consumption in bonito, Sarda chiliensis (Scombridae) J. Mendo, J. Mendo Instituto del Mar del Peru (IMARPE), Apartado 22, Callao-Peru.Search for more papers by this authorD. Pauly, D. Pauly International Center for Living Aquatic Resources Management, MCC P.O. Box 1501, Makati, Metro Manila, Philippines. International Center for Living Aquatic Resources Management, MCC P.O. Box 1501, Makati, Metro Manila, Philippines.Search for more papers by this author J. Mendo, J. Mendo Instituto del Mar del Peru (IMARPE), Apartado 22, Callao-Peru.Search for more papers by this authorD. Pauly, D. Pauly International Center for Living Aquatic Resources Management, MCC P.O. Box 1501, Makati, Metro Manila, Philippines. International Center for Living Aquatic Resources Management, MCC P.O. Box 1501, Makati, Metro Manila, Philippines.Search for more papers by this author First published: November 1988 https://doi.org/10.1111/j.1095-8649.1988.tb05525.xCitations: 5 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References Brett, J. R. (1985). Correction in use of oxycalorific equivalents. Can. J. Fish. Aquat. Sci. 42, 1326–1327. Web of Science®Google Scholar Johansen, K. (1982). Respiratory gas exchange of vertebrate gills. In Gills ( D. F. Houlihan, J. C. Rankin and T. J. Shuttleworth eds), pp. 99–109. Cambridge : Cambridge University Press. Google Scholar Magnusson, J. J. & Prescott, J. H. (1966). Courtship, locomotion, feeding and miscellaneous behaviour of Pacific bonito (Sarda chiliensis). Anim. Behav. 14, 54–67. 10.1016/S0003-3472(66)80011-8 PubMedWeb of Science®Google Scholar Pauly, D., de Vildoso, A. C., Mejia, J., Samamé, M., & Palomares, M. L. (1987). Population dynamics and estimated anchoveta consumption of bonito (Sarda chiliensis) off Peru, 1953 to 1982, In The Peruvian Anchoveta and its Upwelling Ecosystem. There Decades of Change. ( D. Pauly and I. Tsukayama eds), pp. 248–267. ICLARM Studies and Reviews 15. Google Scholar Stevens, E. D. (1972). Some aspects of gas exchange in tuna. J. exp. Biol. 56, 809–823. Web of Science®Google Scholar UNESCO (1973). International Oceanographic Tables, Vol. 2. Godalming and Paris : Ntn. Inst. Oceanogr. Great Britain and UNESCO. Google Scholar Winberg, G. G. (1956). Rate of metabolism and food requirements of fishes. Nauch, Tr. Belorussovo Gos. Univ. imeni. V.I. Lenina, Minsk. (Fish. Res. Bd Can. Tansl. Ser. 194). Web of Science®Google Scholar Citing Literature Volume33, Issue5November 1988Pages 815-817 ReferencesRelatedInformation