Status Of Fisheries Research Articles

Management status of mud crab fisheries in selected areas of FMA 713, East Kalimantan, Indonesia using the Indonesian Ecosystem Approach to Fisheries Management (EAFM) Assessment Methodology

The selected study area in Fisheries Management Area (FMA) 713 in Kartanegara District, East Kalimantan Province, Indonesia has extensive mangrove forests with suitable habitat for mud crabs (Scylla sp.), a valuable fisheries resource. Concerns have been raised regarding reported declines in the abundance of mud crabs and in the condition of their mangrove habitat. To evaluate the management status of the mud crab fishery in this area, an assessment was carried out using the Indonesian Ecosystem Approach to Fisheries Management (EAFM) methodology. The 25 indicators assessed represent 6 domains: Fisheries Resources, Habitat and Ecosystems, Fishing Technology, Social, Economic, and Institutional. The flag model technique was applied using multi-criteria analysis through an expansion of the composite index. The results indicate that the overall management status of mud crab fisheries in Kutai Kartanegara District was in the Moderate class (on a scale of Poor, Insufficient, Moderate, Good, Excellent). Indicators in the Habitat and Ecosystems, Fishing Technology, and Institutional Domains highlighted areas of concern where improvements are needed. The Fisheries Resources Domain aggregate status (moderate) indicated that wild mud crab stocks were still reasonably abundant and reliable, supporting the moderate status in the Social and Economic Domains, which relate to the welfare of fishing communities. The Institutional Domain status was in the poor category. Good governance measures to improve the Institutional Domain indicators have the potential to strengthen the other domains, in particular the Habitat and Ecosystem Domain and the Fishing Technology Domain, and to improve the overall EAFM status of the mud crab fishery in the future.

Assessment of Lobster Fisheries and Sustainable Management Strategies: A Case Study of EAFM in Central Lombok – Indonesia

The exploitation of lobster resources in the waters of the Central Lombok Regency, Indonesia is not effectively managed, causing problems in terms of resource availability and sustainability of lobster fishing operations. This study aimed to assess the status of lobster fisheries management and policy strategies for sustainable lobster fisheries management. Data were collected in three lobster fishing centres: Teluk Awang, Teluk Bumbang and Teluk Gerupuk. Methods used were a structured interview technique with questionnaires, focus group discussions (FGDs) and public consultation. The status of the lobster fishery was analysed using the Ecosystem Approach to Fisheries Management (EAFM) indicators with six Domains. The lobster fishery management status was classified as “moderate” (aggregate score 50/100). The Fisheries Resources Domain scored 35, indicating that lobster stocks are in “poor” condition. Four dimensions had a “moderate” status: the Fisheries Technology Dimension (43), the Economic Dimension (48), the Social Dimension (53), and the institutional dimension (55). The Habitat and Ecosystem Dimensions was classified as “good” (67). Sustainable lobster fisheries management strategies include regulating fishing quotas, banning gears which catch lobster seed, and optimizing the use of selective fishing gear; establishing a working group for lobster management; managing water quality and zonation of lobster habitat; transfer of lobster farming techniques; and empowering community coastwatch groups.

Ecosystems Approach to Fisheries Management (EAFM) assessment for grouper and snapper fisheries in Bontang, East Kalimantan, Indonesia

Groupers and snappers are two demersal fish groups that are currently experiencing heavy fishing pressure both for the live reef fish trade and as fresh or processed fisheries commodities across the Coral Triangle. The purpose of this study was to assess the status of grouper and snapper fisheries in the Bontang region, East Kalimantan, Indonesia using Ecosystems Approach to Fisheries Management (EAFM) indicators. The assessment followed the Indonesian EAFM Assessment Guidelines methodology, with 6 Domains (Fisheries Resources, Habitat and Ecosystems, Fishing Technology, Social, Economy, and Governance) and 32 indicators. Data were collected through a desk study and site visits including key informant interviews, direct observation and secondary data collection. With the exception of the Social Domain, at least one indicator in each Domain was in the Very Poor category, and three indicators were in the Poor category. Management policies and actions are needed to maintain the overall Good status and address the issues threatening sustainability.

Fishery Improvement Projects (FIPs): A global analysis of status and performance

Fishery Improvement Projects (FIPs) have been increasing in numbers worldwide over the last decade to improve fishery practices towards sustainability. This paper tries to analyse the current status and performance of fisheries currently involved in FIPs and listed in the website Fishery Progress (www.fisheryprogress.org). Out of the 126 analysed FIPs, 59 FIPs did not show any changes in status, in addition to 6 FIPs with no status information. These fisheries double the total landings of the fisheries that showed improvements. The results reveal that young FIPs (those 2 years old or less) account for 42 out of the 59 that did not show any changes in status. Weak relationship between the improvements in scores and actions completed or cumulative duration (spent time) of the project was observed. FAO areas with highest scores were in the northern hemisphere while the lowest were in the south. The finding of fisheries scoring poorly in the global south may reflect data gaps rather than poor performance, or a mixture of the two that demands care of interpretation.

Historical distribution of Arctic lamprey Lethenteron camtschaticum in Japanese rivers and its change estimated from fishery statistics and fishers’ local ecological knowledge

This study identified the location and geographical characteristics of rivers where Arctic lamprey Lethenteron camtschaticum were captured in the past and present in Japan and evaluated the effectiveness of the local ecological knowledge (LEK) held by inland fishers for estimating species distribution. We collected information about fishery harvests for Arctic lamprey from fishery statistics published in the 1930s and directly from inland fishery cooperatives (FCs). The presence of a historical harvest and its southern limit were largely consistent between the two resources. The fishery harvest was historically distributed in relatively large rivers, with a low downstream gradient, along the Sea of Japan, and the southern limit was estimated to be in the range of 36.45–37.33° N. The number of active FCs decreased from a historical value of 59 to only 14 at present. The southern limit shifted further north to 43.13° N. The LEK from FCs provided sufficient information to estimate the spatial distribution within the local rivers and revealed that a decline in fishery activity had occurred in the upper reaches of rivers. Our data can be used as a baseline for the restoration of Arctic lamprey and to develop a monitoring tool to improve the conservation of inland biodiversity.

Management of scad fisheries (Decapterus spp.) in Sulawesi Sea Waters, North Sulawesi Province, using EAFM

There are a large variety and quite abundant types of small pelagic fish that have high economic value in the Sulawesi Sea. One of which is the blue scad fish or commonly known as malalugis (Decapterus macarellus). This study aims to analyze and determine the status of scad fisheries management and to develop recommendations in the management of scad fisheries in the waters of Sulawesi Sea, North Sulawesi Province. The evaluation of fishery management status is carried out using multi-criteria analysis (MCA) through the development of composite index of each indicator of Ecosystem Approach to Fisheries Management (EAFM). The results showed that, in general, the status of scad fisheries management in North Sulawesi Province, was in ‘good’ category, specifically reviewed from the domain of fish resources fall into the category of “medium”, habitat and ecosystem “good”, fishing techniques “good”, economy “not good”, social “medium” and institutional “good”. Management actions take precedence over domains that have “poor” indicator values. Priority management action is implemented in the economic domain, followed by the domain of fish resources, social, institutional and fishing techniques.Indonesian title: Pengelolaan perikanan ikan layang (Decapterus spp.) di perairan Laut Sulawesi, Provinsi Sulawesi Utara, menggunakan EAFM

Modern specialized fishery of sea fish in the western Bering Sea

The shelf and continental slope of the western Bering Sea, being among the most productive areas of the Far-Eastern Seas of Russia, became exploited by commercial fishery half a century ago, after introduction of 200-mile exclusive economic zones in 1977 and relocation of the Russian fishing fleet from the eastern Bering Sea to its western part. In 2010-2019, about 20 % of the total catch of sea fish in the Far-Eastern basin (excluding pacific salmons) were caught in the West Bering Sea fishery zone. Among the fishery districts of the Russian Far East, this area is currently the 1st one by annual catch of pacific cod, grenadiers, sculpins and sablefish, 2nd— by catch of walleye pollock, halibuts and skates, 3rd— by catch of rockfishes, and 4th— by catch of pacific herring and flounders. Features of specialized fishery in the West Bering Sea fishery zone in 2010-2019 are clarified. Now 48 types of the specialized fishery can be distinguished here, while 96.3 % of the average annual landing is provided by the following 8 most important types: walleye pollock midwater trawl fishery (77.8 % of mean annual catch); pacific herring midwater trawl fishery (6.1 %); pacific cod bottom longline fishery (4.7 %); walleye pollock Danish seine fishery (2.7 %); grenadiers bottom longline fishery (2.4 %), pacific cod Danish seine fishery (0.9 %); squids bottom trawl fishery (0.9 %); and pacific cod bottom trawl fishery (0.8 %). All these types of fishery are highly specialized and portion of the target objects in the catches ranges from 76 to 96 % (according to official statistics), while the by-catch accounted as 4-24 %. The is no specialized fishery on such objects as rockfishes, arrowtooth and kamchatka flounders, and sablefish in the West Bering Sea fishery zone, but they are landed as by-catch. The fishery statistics with the data sorting to specialized fishery and by-catch can be used quite effectively for the stocks assessment and determining acceptable level of their exploitation, with recommendations for fishery regulation, including evaluation the possible level of non-specialized by-catch.

Assessing Bali sardine stock status using real-time electronic catch landing data recorder and time series catch database

Digitalization of capture fisheries data becomes inevitable in the present and future time. The use of Information and Communication Technology (ICT) in the fisheries sector is widely applied, creating a bigger and better database. Development of the database offers the utilization of Big Data and Decision Support System (DSS) to provide robust analysis, simulate better scenarios, formulate recommendations, and propose management measures to support successful fisheries management in achieving sustainability and profitability objectives. Bali Strait sardine stock estimation has been conducted several times through several approaches and techniques. This study will combine the available times series catch and effort data from published statistic landing data and publications with real-time data from electronic catch monitoring in Muncar and Pengambengan fishing port. The sardine stock and fishery status estimation were analyzed using a stock-production model incorporating covariates (ASPIC), a Nonequilibrium surplus-production model to data on fish catch and relative abundance. Another purpose of this study is to increase stakeholder participation through a smart dashboard system that enables automatic data analysis, faster recommendations socialization, and engagement. Increased stakeholder participation in fisheries management will be a crucial factor in achieving operational and successful fisheries management.

Unveiling the unknown phylogenetic position of the scallop Austrochlamys natans and its implications for marine stewardship in the Magallanes Province

Two species of scallop, Austrochlamys natans (“Ostión del Sur”) and Zygochlamys patagonica (“Ostión patagonico”) are presently exploited in the southern part of the Magallanes Province (MP). The lack of clarity in taxonomic identification and ecological aspects is generating both erroneous extraction statistics and an unperceived harvesting pressure on A. natans and Z. patagonica. We aim to discriminate these Magallanes scallops accurately, improve our understanding of their complex natural history and discuss possible implications for their management and conservation status, given the current fisheries statistics. To achieve these goals, we present a complete review of the historical identification of the Magallanes scallop and a multi-locus molecular phylogeny which allowed us to recover the phylogenetic position of A. natans. We sampled 54 individuals from five localities across the southern Pacific coast of the MP. We calculated the depth of the byssal notch (BND) and shell height (VH) ratio from morphological characters and conducted phylogenetic reconstructions with mitochondrial (12S and 16S) and nuclear markers (28S) using Bayesian and maximum likelihood analyses. Both morphology and molecular phylogeny identified two distinct entities, Z. patagonica and a distinct, highly divergent lineage that corresponds to A. natans. Our study provides integrative evidence to alert the current fishery management and the need for further conservation studies.

Demography of swordfish (Xiphias gladius Linneus) populations from the coasts of Turkey, based on mitochondrial DNA and microsatellites.

The genetic diversity of the Mediterranean swordfish (Xiphias gladius Linneus) has not been explored extensively at its easternmost range so far. In this study, modern X. gladius samples from the eastern part of the Mediterranean basin, north of the Aegean Sea (Aegean-2013, n=26) and the Mediterranean coast of Turkey (N.Levantine-2013, n=42) were studied genetically, along with ancient samples from Yenikapı excavation (n=6). Partial mitochondrial DNA control region sequences (entire sequences, clade I and clade II) were evaluated spatially and temporally together with previously published sequences (Alvarado Bremer et al., Molecular Phylogenetics and Evolution, 2005, 36, 169-187; Viñas et al., ICES Journal of Marine Science, 2010, 67, 1222-1229; Righi et al., Diversity, 2020, 12, 170) from the rest of the Mediterranean Sea. Pair-wise FST and pair-wise AMOVA tests showed that, in general, groups of eastern populations and western Mediterranean populations have not genetically differed from each other significantly nearly in the past 20 years. Therefore, the results direct reconsideration of previous descriptions of population sub-structure within the Mediterranean and support high gene flow throughout the region. On the contrary, the results of this study confirmed the existence of genetic diversity differences between western and eastern Mediterranean, with eastern being low. One-tailed permutation tests revealed that θ, which is directly proportional to long-term female effective population size (Ne), decreased significantly (P < 0.05) in both regions over the past two decades. On the Turkish coasts, θ is not significantly different from that of the nearly contemporary eastern Mediterranean population. Nonetheless, θ of the ancient sample was consistently and significantly (P < 0.001) higher than those of the eastern and western Mediterranean populations in clade I and clade II. Furthermore, it contains two mitochondrial haplotypes that are not observed in modern samples, suggesting that the Ne of X. gladius in the eastern was high in Byzantium times. Eight microsatellite loci were also genotyped in modern samples. The microsatellite-based present Ne estimate of the pooled Aegean-2013 and N.Levantine-2013 populations was lower than 1000 according to the upper limit of 95% c.i. and possibly even lower than 100 according to the mean of posterior distribution of the present Ne estimate calculated by the software package MSVAR. These alarming genetic signals for the sustainability of X. gladius on the coasts of Turkey are in agreement with the nearly collapsing X. gladius fisheries as depicted also in the fisheries statistics. Overall, congruent with the previous studies, the data presented here show that sustainability of the X. gladius population in Mediterranean is under major threat. Therefore, X. gladius around the Turkish coasts need an immediate stringent action and management plan.

Ecotrophic Effects of Fishing across the Mediterranean Sea

The status of the Mediterranean Sea fisheries was evaluated across the seven subdivisions of the General Fisheries Commission for the Mediterranean (GFCM), using ecotrophic and catch-based indicators for the period 1970–2017. All indicators confirmed that the fishery resources across the Mediterranean Sea are no longer sustainably exploited and that the structure and function of marine ecosystems has been altered as a result of overexploitation. Although declining catches were a common feature across the Mediterranean Sea, the pattern of exploitation and the state of stocks differed among the subdivisions, with the Levantine Sea and Sardinia having a better status. Although they only include the exploited biological resources of marine ecosystems, catch and ecotrophic indicators can provide insight on ecosystem status and fishing pressure. In the case of southern Mediterranean countries, catch and trophic levels are the only information available, which is extremely valuable in data-poor ecosystems.

Male Deep-Sea Shrimps Aristeus antennatus at Fishing Grounds: Growth and First Evaluation of Recruitment by Multilocus Genotyping

The population biology of the deep-sea shrimp Aristeus antennatus, as with other exploited demersal species, is usually studied using data from fishery statistics. Such statistical analyses have shown female-biased sex ratios during the spawning season in this species. Because the abundance of males increases at greater depths that are not exploited by fisheries (virgin grounds), knowledge on their recruitment is limited. Here, the growth and recruitment of A. antennatus males at fishing grounds was evaluated. This was achieved by integrating information on previously identified breeding behaviours and by tracing the young-of-year cohort through genotyping at 10 microsatellite loci. Using a codend and a codend cover with distinct meshed windows, four groups of males were collected in winter and in a subsequent spawning summer season. Summer collections were mostly composed of pre-adult males, reaching sizes that are to be expected from the growth of winter juveniles; however, many specimens also originated from nearby grounds. This result indicates the horizontal dispersal of male juveniles via intermediate and deep oceanographic currents. Such dispersal complements passive larval dispersal in surface waters, and contributes to the weak genetic divergence among regional fishing grounds. These features could be shared by other deep-sea crustacean and fish species, and should be considered for the sustainable exploitation of demersal fisheries.

Current status and potential contributions of fisheries statistics from artisanal fisheries for managing juvenile istiophorid billfishes in Southern Brazil.

Billfishes are considered important fishery resources and the identification of aggregation sites is imperative for proper management. Here we present evidence of a seasonal aggregation site for juvenile istiophorid billfishes in southern Brazil. We discuss the results as they relate with the need for management at a local scale and participatory monitoring with artisanal fishing communities as a way to ensure access to data on the occurrence and population status in the long term.

Length-Based fishery status of Yellowfin tuna (Thunnus albacares Bonnaterre, 1788) in the northern waters of the Oman Sea

In the present study, population characteristics of Thunnus albacares were evaluated by sampling at five fish landing sites in the northern Oman Sea including Beris, Ramin, Pozm, Konarak and Jask from March 2017 to March 2018. The biometric analysis was performed on more than twenty-six thousand fish. Population dynamic parameters were calculated including infinite length (L∞=171 cm), growth coefficient (K=0.54 (yr-1)), growth performance index (Ф'=4.19), natural mortality (M= 0.71(yr-1)), fishing mortality (F=1.57 (yr-1)), total mortality (Z=2.28±0.19 (yr-1)), exploitation coefficient (E=0.68 (yr-1)) and initial condition parameter (-0.18 yr-1). Relative production per recruitment, relative biomass per recruitment and exploitation rate of this species were Y'/ Rp = 0.04, B'/ Rp=0.23(yr-1) and U=0.62 (yr-1), respectively. The Pobj value is 0, and F/Fmsy>1. The results indicated that regarding length frequencies of this species in the northern part of the Oman Sea, yellowfin tuna stock has good conditions, but overfishing of this species is happening, now. Therefore, specific measures should be taken to reduce catch and fishing effort.

The status of Macrobrachium fishery and its market in southern Ghana

Ghanaian fisheries is dominated by the marine sector which contributes 60-65% of total fish catch while the inland sector supplies 30-35%. Although finfishes are the main species captured in the inland sector, freshwater prawns of the genus Macrobrachium are exploited on artisanal basis at the Volta River estuary. An exploratory study was conducted in the South Tongu District, Volta Region in Ghana, to ascertain the status of the prawn fishery: identify the species harvested, harvesting methods, catch statistics as well as the marketing chain. Data on the species harvested and catch statistics were based on artisanal fishers’ landings and field observations. Additionally, interviews were conducted with prawn fishers, processors and retailers to elicit information on the marketing chain of harvested prawns. Five species of prawns were identified: Macrobrachium vollenhovenii, Macrobrachium dux, Macrobrachium macrobrachion, Macrobrachium lar and Atya gabonensis with the first three being the most abundant. The prawns were harvested with baited basket traps conveyed in canoes to areas in the river where prawns are known to occur. The total annual catch estimated from the output of the 23 fishers was 6,230.4 kg over 236 fishing days year-1. Mean catch per fisher was 2.4 kg day-1 which was similar in the three fishing communities. Agave-Afedome however, had more fishers and contributed 80% of the total catch. Frying and roasting were the common processing methods used. All actors in the chain (fishers, processors and retailers) complained of low and inadequate supply of prawns and advocated the development of a sustainable fishery in this area.

Size matters: identity of culturally important herrings in northeastern Brazil

Fishery statistics are mainly made by recording the popular fish names, which is later translated into scientific identification. However, these names often either refer to a species group and/or vary along their distribution, increasing identification uncertainty. Species that have cultural value for traditional communities are known as culturally important species (CIS). Herein, we assessed Fishers’ Ecological Knowledge to investigate small-silvery herrings (ginga) used as part of a traditional dish \ginga com tapioca", that is recognized as a cultural heritage in the Brazilian northeastern. Through 103 interviews conducted in six communities in three states, we determined that ginga, although a name known elsewhere, is only traded as such in the metropolitan area of Natal. In this region, ginga is caught with drift net and deemed profitable by fishers. We identified both over- and under-differentiation, with ginga recognized by fishers as five, and sold as three main species, namely Opisthonema oglinum, Harengula sp., and Lile piquitinga. The larger specimens of two of those species (O. oglinum and Harengula sp.) were also traded as sardines. We found that most individuals sold as ginga were juveniles, which might impact the recruitment of some fish species. Due to its unique cultural relevance to the local community of Natal, ginga could be considered a CIS, which could aid future management or conservation measures.

PRELIMINARY STUDY OF IMPACT WARMING EFFECT TO SPRAT QUALITY CHARACTERISTICS IN RUSSIAN WATERS OF THE BLACK SEA (1951-2019)

Preliminary study of impact of temperature factor to sprat quality characteristics in Russian waters of the Black sea in period 1951–2019 was performed. In this research statistical hyphothesis about relationship between indicator sea surface temperature factor near to Chernomorskoe, Yalta, Feodosia and long-term sprat mean weight fishery statistics was done. Linear relationship hyphothesis performed by Pearson correlation test. Preliminary cross-correlation test results shows significant moderate relationship between temperature factor average and mean sprat weights (r = –0,60). After preliminary diagnostics input data was smoothed by polynomial regression to reduce interannual fluctuations and cross-correlation test to smoothed data was repeated. Correlation test by smoothed data indicate strong negative (r = –0,75) relationship between long-term sea surface temperature in all indicator points and mean sprat weights and high powerful relationship between sea surface temperature and oldest sprat classess (r = –0,86). Performed study underline the primary part of temperature factor and warming effect to degradation result in Black sprat fishery quality characteristcs. Global warming effect starting from 1990 made significant negative impact into sprat environment in the Black sea

The Lost Coin: Redefining the economic and financial value of small-scale fisheries, the case of Lake Victoria, Kenya

Abstract Whereas small-scale fisheries account for the largest proportion of fish catches and employment in most developing countries, their value remain underestimated due to inadequate data collection systems, open access challenges and unreported landings. This study provided a methodological option to compare, contrast and validate official fisheries statistics in small-scale fisheries of Lake Victoria, Kenya. A standardized Fishing Business Model (FBM) was applied to reconstruct estimates of economic returns from Lake Victoria fisheries; taking into account fish auto-consumption, post-harvest losses and landings from illegal gears which are often missing in the official estimates. Primary data was collected using electronic questionnaires in various fish landing sites in July 2020 while secondary data was sourced from latest surveys on fish stocks, catches and fishing effort in the lake. Results indicate that fish catches amounted to 151,002 mt (Sd = 1767.0), which implies 1.6 times the official estimates, and that Total annual Fishing Revenue (TFR) was USD 297, 172, 579.39 (Sd = 2,674,359.0) which was 1.9 times higher than published statistics. Further, a small-scale fisher was found to earn a daily wage of USD 17.6, inclusive of the value of auto-consumption, under-sized fish and other unsold catch which are usually unreported. We recommend a review of official fisheries statistics in order to correct under-valuation in small-scale fisheries and to re-adjust the management cost recovery and revenue allocation frame-work in the fisheries sub-sector. This study thus makes a valuable contribution to literature on income and cost analysis for different fishing enterprises in small-scale fisheries.

Optimizing the Utilization of Genetic Resources of Indonesian Native Freshwater Fish

Indonesia has a long story in the documentation of the richness of fish genetic resources. Identifying and documenting the diversity of fish species showing the country has around 1700 species. However, Fishbase records only 1258 species (10% contribution to the world) indicating around unrecorded 442 species (26%) in the site. Significant pressures on fish genetic resources and its habitat, small new species documentation/loss of existing species, a decreasing percentage of species at the global level, and un-optimal utilization seems to be essential issues. To deal with these issues, the re-inventory of Indonesia's freshwater fish genetic resources needs to be conducted with concern on unrecorded data in FishBase and threatened species. The government needs to increase awareness on establishing fisheries status through the implementation of the Ecosystem Approach to Fisheries Management (EAFM) for better fisheries management programs. Improvement of preservation and utilization programs for potential native fish species is also essential to provide alternatives species for aquaculture development and its conservation and the last is habitat rehabilitation through nature reserves empowers rules and strengthens regulation. To achieve action plan targets, cross-sectoral coordination is needed in which institutions involved in policy authority, scientific authority, and management authority must synchronize their programs and actions.

Almost forgotten: Historical abundance of eel-tail catfish populations in south-western Australian estuaries and their decline due to habitat loss and historical overfishing

The decline of Estuary Cobbler (Cnidoglanis macrocephalus) stocks in south-western Australia since European settlement of the region in 1829 is described, based on evidence from historical documents, fishery statistics and scientific surveys. Estuary cobbler is a relatively large, long-lived, benthic carnivore that was once abundant in the three largest west coast estuaries, where it was a major component of fishery catches for decades. The breeding stock in each estuary declined dramatically between 1960 and 2000, after which time exploitation effectively ceased. Two stocks appear to have largely disappeared, while the third still persists at a relatively low level. In each estuary historical overfishing coincided with a period of severe habitat degradation including flow modification, eutrophication, benthic habitat loss and hypoxia. Hence there is no obvious, primary driver of decline for these stocks. Exploitation probably acted synergistically with environmental impacts to cause each stock decline. In degraded environments, fisheries management should be highly precautionary to reflect the elevated risk to exploited species posed by multiple simultaneous stressors. A risk-based ‘weight-of-evidence’ approach that can accommodate both quantitative and qualitative lines of evidence, including fishing and non-fishing impacts, is recommended to assess the status of exploited species in such environments.