Crab Harvest Research Articles

Stock status and spawning potential ratio of orange mud crab (Scylla olivacea, Herbst 1796) in the southwestern coastal waters of Bangladesh

Scylla olivacea (Orange mud crab) is a second commercial invertebrate species exported from Bangladesh. Though a significant portion of exports are supported by aquaculture, their farming ultimately depends on their wild stocks. Unfortunately, unregulated exploitation has led to a significant decline in the natural biomass of this species, raising concerns about the sustainability of crab production in Bangladesh. The study aimed to assess the stock status of S. olivacea (Orange mud crab) from the Southwestern coastal water of Bangladesh. One-year length frequency (width frequency-WF for crustacean fishery) data were collected and analyzed using the LBB (Length-based Bayesian Biomass) and LB-SPR (Length-based spawning potential ratio) methods. The assessed width parameter depicted the exploitation of small-size individuals (Wc=< Wc_opt) of S. olivacea. The estimated B/B0 (0.25) suggests that 75 % of the wild stock had already been harvested, and biomass cannot produce MSY. The mean estimates for SW50 % and SW95 % were 8.29 cm and 12.76 cm respectively, revealing the use of a small mesh-size net for crab harvesting. The assessed Spawning Potential Ratio (SPR) was 12 % which is below the SPR limit reference point (SRP) of 20 %. This research confirmed the overfished (F/M = 1.4) and overexploited (E = 0.58) status of S. olivacea in Bangladesh. To ensure the sustainability of coastal fisheries in Bangladesh, the authorities must take immediate management measures to control the overexploitation of this species.

PSV-29 In vitro digestibility and in situ degradability of lobster and mixed crab shell waste material

Abstract The objective of this research was to determine the in situ and in vitro degradability of lobster shell waste meal (LM) and crab shell waste meal (CM). Lobster and crab harvest are major industries within the New England states and the Maritime provinces. Harvest of the American lobster amounts to 54,643 tons caught and processed in 2020 in the New England states. The Atlantic Red Crab annual quota is around 1,814 tons. The Jonah Crab amounts to 5,725 tons. Due to the significant harvest, there is a resulting increase in byproducts and wastes at processing facilities providing potential feedstuffs for cattle. For both experiments, LM and CM were compared with soybean (SBM) and blood meals (BM). In experiment 1, 0.5 g of each meal were added to an artificial rumen incubator (Daisy, Ankom technologies) and DM degradability over 48 h was measured. In experiment 2, ruminally-cannulated Holstein cows (n = 4) in a 4 × 4 Latin square, had 5 g of sample were placed in Dacron bags in the dorsal rumen. Bags were in duplicate and removed at 2, 4, 8,12, 24, and 48 h time points. Eight bags were removed at 12 h for use in the in vitro intestinal degradability measurement using the modified three-step technique. Contrasts were: SBM vs. BM+LM+CM (SBM vs others), BM vs. LM+CM, and LM vs. CM. In experiment 2, 0 h bags served as a determination of fraction A, while the 48 h bags served as fraction C. Fraction B = 100% - (fraction A + fraction C). Degradation rate (kd) was calculated by converting % CP degraded from 2 to 24 h to Ln and then calculating the slope. In experiment 1, DM degradation was 45.8, 43.8, 76.4 and 100.1 % for SBM, BM, LM, and CM respectively; SBM vs others (P &amp;lt; 0.01), BM vs. LM + CM (P &amp;lt; 0.01), and no difference between LM vs. CM. Fraction A (CP) was 9.9, 8.1, 4.2, and 4.8% respectively; with SBM vs. others (P &amp;lt; 0.03), BM vs. LM+CM (P &amp;lt; 0.01), and no difference between LM vs CM. Fraction B (CP) was 76.2, 62.2, 28.9, and 42.6% respectively; with SBM vs. others (P &amp;lt; 0.01), BM vs. LM + CM (P &amp;lt; 0.01), and LM vs. CM (P &amp;lt; 0.10). Fraction C (CP) was 4.41, 30.8, 46.8, and 37.5% respectively; with SBM vs. others (P &amp;lt; 0.01), BM vs. LM + CM (P &amp;lt; 0.03), and LM vs. CM (P &amp;lt; 0.08). Intestinal CP digestibility was 56.2, 64.7, -5.83, and 10.5% respectively, with SBM vs others (P &amp;lt; 0.01), BM vs LM+CM (P &amp;lt; 0.01), and no difference between LM and CM. Results of these studies indicated that LM and CM may have some benefits in cattle diets, but feeding studies should be conducted.

A regional analysis of climate change effects on global snow crab fishery

AbstractThe snow crab fishery faces increasing vulnerability to environmental factors, yet the literature on the relationship between climate change and snow crab harvest remains limited. This study estimates snow crab harvest functions using climate change indicators with unbalanced panel data of snow crab production from the eastern Bering Sea (Alaska), the southern Gulf of St. Lawrence (Canada), the Sea of Japan, and the Barents Sea (Norway‐Russia). The relationship between snow crab biomass, stock, and catch is analyzed and the endogeneity of stock in the harvest function is also addressed using climate change indicators as instrumental variables (IVs). The results show that the extent of Arctic sea ice is effective in addressing the endogeneity, and the random effects IV model with error components two stage least squares estimator performs the best to control heterogeneity. A 1% increase in snow crab fishing effort is associated with a 0.42% increase in snow crab harvest, and a 1% increase in snow crab stock causes a 0.98% increase in snow crab harvest. The reported estimates indicate a large stock‐harvest elasticity and provide supporting evidence to prioritize stock enhancement in snow crab fishery policy designs to maintain stocks at sustainable levels and minimize government expenditures on subsidies.Recommendations This study explores how snow crab harvests are influenced by snow crab populations and fishing efforts in the context of global warming across various global regions, including the Bering Sea, the Gulf of St. Lawrence, the Sea of Japan, and the Barents Sea. A 1% increase in fishing effort is associated with a 0.42% increase in harvest, while a 1% increase in snow crab population leads to a 0.98% increase in harvest, showing a high dependency on snow crab biomass. Arctic sea ice extent is identified as a crucial climate factor affecting snow crab biomass and harvests, making it a valuable variable for understanding and managing snow crab populations. The study supports the prioritization of stock enhancement policies by fishery agencies and suggests standardizing how fishing effort is measured across different regions to improve snow crab fishery management and future research.

Crab Harvesting, Sustainability Issues, and International Trade: Insights from Russia

This article aims to analyze Russia’s efforts, both domestically and internationally, to combat illicit crab harvesting and safeguard its marine resources. A comparison of total crab imports and allowable catch in Russian waters from 1990 to 2022 indicates a peak in shadow activities during the mid-2000s, with a cessation of large-scale illegal fishing observed since 2013. A narrative analysis of institutional shifts reveals that the bolstering of internal oversight, heightened accountability for harvesters, and enhanced global cooperation have been pivotal in fostering these positive dynamics. Concerning trends, however, emerged towards the beginning of the current decade, indicating potential instability within the legal framework of the crab industry. Persistent statistical discrepancies in trade with South Korea, diminishing institutional capacities within Russia to combat shadow activities, and heightened media scrutiny of illicit crab harvesting underscore the need for sustained vigilance in addressing both internal and external dimensions of this multifaceted problem.

Application of a catch multiple survey analysis for Atlantic horseshoe crab Limulus polyphemus in the Delaware Bay

AbstractObjectiveThis paper applies a catch multiple survey analysis (CMSA) to Atlantic horseshoe crabs Limulus polyphemus in the Delaware Bay to generate robust population estimates for harvest management. Currently, horseshoe crabs along the U.S. Atlantic coast are harvested as bait for other fisheries and collected for their blood, which is used in a biomedical industry. The Delaware Bay is home to the largest population of horseshoe crabs and is a significant stopover for shorebirds to rebuild energy by consuming horseshoe crab eggs prior to completing their northward migration. To address this interrelationship, the Adaptive Resource Management (ARM) Framework has been used since 2013 to ensure that horseshoe crab harvest within the region takes into account the forage needs of migratory birds. Since its inception, the ARM Framework has used a single trawl survey's swept area‐based population estimates of horseshoe crab relative abundance and a theoretical population model developed primarily from literature‐derived values. With more data collected in the region in recent years and other sources of mortality that can now be quantified, a catch survey model can provide horseshoe crab population estimates going forward.MethodsA CMSA was used to estimate male and female horseshoe crab population size for 2003–2021 using all quantifiable sources of mortality and three fishery‐independent indices of abundance.ResultThe CMSA results indicated that adult abundance of male and female horseshoe crabs was stable from 2003 to 2013 and then began to increase through 2017, a result that is consistent with stock rebuilding following a period of harvest restrictions as recommended by the ARM Framework. Population estimates were lower in recent years but remained above the levels estimated before implementation of the ARM Framework. In 2021, the CMSA estimated that there were over 6 million mature females and nearly 16 million mature male horseshoe crabs in the region.ConclusionThe CMSA provides the best and most comprehensive population estimates of horseshoe crabs in Delaware Bay and will improve modeling efforts within the ARM Framework going forward.

Environmental drivers of variation in southeast Australian Giant Mud Crab (Scylla serrata) harvest rates

Catch rate data is typically used as a proxy for relative abundance in stock assessment model, under the assumption of constant catchability. However, environmental variation and operational aspects of a fishery can decouple catch rates and abundance. As such, there is a need to quantify drivers of variation in catchability to enable robust stock assessment. Here, we present an analysis of Giant Mud Crab (Scylla serrata) catch rate data, obtained from a fishery-wide observer program implemented in southeast Australia (i.e., New South Wales, NSW). Using generalized additive mixed models (GAMM), we examined the influence of ‘soak’ (or immersion) time of commercial traps, water temperature, river flow, wind speed and lunar phase while controlling for gear configurations (e.g., number of entrances/escape gaps) and fisher ‘skill’. Our modelling showed soak time has little effect on catch rates, while warmer temperatures generally enhance catch rates. To a lesser degree, river flow, wind speed and the lunar phase also influenced catch rates. Overall, our results emphasize the importance of quantifying the impact of environmental variation on catch rates to ensure they are a reliable proxy for relative abundance when incorporated into stock assessments.

Snow crab (Chionoecetes opilio) hemocytes and hepatopancreas transcriptomes: identification, validation, and application of immune-relevant biomarkers of exposure to noise

The snow crab (Chionoecetes opilio) fishery off the east coast of Newfoundland and Labrador, Canada, has been impacted by annual seismic oil and gas surveying in recent decades, and commercial crab harvesters are concerned that it could potentially affect this resource. A laboratory study was performed to investigate the effects of chronic noise exposure on the transcriptomes of snow crab hemocytes and hepatopancreas, which are important in immunity, metabolism and response to environmental stress. Snow crab were held in replicate control or experimental tanks; on alternating days, the experimental tanks were exposed to noise from an underwater speaker which played a recording of a seismic airgun firing every 10 sec in a continuous loop for ~ 22 weeks (chronic noise). RNA sequencing was used to identify candidate noise-responsive molecular biomarkers in both hemocytes and hepatopancreas. The quantified transcripts of individuals (i.e. n=10 from each of the four groups) were compared using DESeq2, identifying over 300 noise-responsive transcripts in each cell/tissue type. Real-time quantitative polymerase chain reaction (qPCR) assays were designed and run for 61 of these transcripts with significant BLASTx hits. One transcript (rgs2) was significantly (p &amp;lt; 0.05) higher expressed in both hemocytes and hepatopancreas in response to noise; five and seven other transcripts were either significant or showed a non-significant trend of differential expression (0.05 &amp;lt; p ≤ 0.1) in hemocytes (e.g. cfb upregulated, sacs and myof downregulated) and hepatopancreas (e.g. gpx3 and atf3 upregulated, sult1c4 downregulated), respectively. To further investigate the performance and utility of these candidate biomarkers in the field, expression levels of 25 selected transcripts were then examined in the hepatopancreas of snow crab that had been subjected to 2D and 3D seismic surveying using both qPCR and multivariate statistical analyses. Overall, few of these biomarkers showed consistent results in field-collected snow crab, highlighting the need to combine lab and field-based studies to fully evaluate the utility of biomarkers. Nonetheless, our study still identified noise-responsive biomarkers in both settings (including stress and immune relevant genes), providing valuable information for understanding the impact of ocean noise on snow crab physiology and health.

A fishermen-developed intervention reduced musculoskeletal load associated with commercial Dungeness crab harvesting

This study characterized physical risk factors associated with injuries during a Dungeness crab harvesting task and evaluated the efficacy of a fishermen-developed ergonomic control (banger bar) in mitigating physical risk factors, including biomechanical loads in the low back, shoulders, and upper extremities, and postural instability. In a repeated-measures laboratory study, 25 healthy male participants performed manual crab harvesting tasks in five conditions: without any banger bar (control) and with 4 bars of differing heights or designs. The results showed that the ergonomic control reduced trunk and shoulder angles, L5/S1, and shoulder moments; muscle activities in low back, shoulders, and upper extremities; perceived exertion ratings; and postural sway measures. Moreover, these measures were lowest when the bar height was at 60 cm, indicating that the banger bar can reduce the risk of musculoskeletal injuries and postural instability, and that bar height is an important factor affecting these injury risk measures.

Estimating recruitment rate and population dynamics at a migratory stopover site using an integrated population model

AbstractConsideration of the full annual cycle population dynamics can provide useful insight for conservation efforts, but collecting data needed to estimate demographic parameters is often logistically difficult. For species that breed in remote areas, monitoring is often conducted during migratory stopover or at nonbreeding sites, and the recruitment rate of new breeding adults can be difficult to estimate directly. Here, we present an integrated population model that uses mark‐resight and count data to estimate survival probability, population growth rate, and recruitment rate for an Arctic‐breeding shorebird of conservation concern, the red knot (Calidris canutus rufa), from data collected during spring stopover in Delaware Bay, USA, from 2005 to 2018. At this site, red knots feed primarily on the eggs of spawning horseshoe crabs (Limulus polyphemus), a legally harvested species. We used this model to estimate the relationship between horseshoe crab abundance and red knot demographics, which informed a recent revision to the framework used to establish horseshoe crab harvest regulations. Our analysis indicates that the red knot population was most likely stable from 2005 to 2018 (average λ = 1.03, 95% credible interval [CRI]: 0.961, 1.15) despite low recruitment rates (average ρ = 0.088, 95% CRI: 0.012, 0.18). Adult survival probability was positively associated with horseshoe crab abundance in the same year (β = 0.35, 95% CRI: 0.09, 0.63), but we found no effect of horseshoe crab abundance two years previously on recruitment of new adults (β = −0.08, 95% CRI: −0.41, 0.38). Our approach demonstrates the utility of integrated population models for understanding population dynamics, even when data are only available from migratory stopover monitoring.

Horseshoe crab egg availability for shorebirds in Delaware Bay: Dramatic reduction after unregulated horseshoe crab harvest and limited recovery after 20 years of management

Abstract The largest aggregation of spawning American horseshoe crabs in the world occurs in Delaware Bay and supports one of the largest concentrations of shorebirds in the western hemisphere where the birds feed on horseshoe crab eggs during migration. Unregulated harvest in the 1990s is associated with the decline of shorebird populations using the bay, but corresponding baseline information on the horseshoe crab egg food supply that supported peak shorebird populations has been lacking. Past and current measurements of horseshoe crab eggs in the bay indicate that abundance in the 1980s was an order of magnitude greater (x̄ = 156,600/m2) than present‐day estimates (2015–2021 x̄ = 10,243/m2). An additional egg prevalence index, which characterizes the timing and magnitude of horseshoe crab egg output, revealed a similar pattern of higher prevalence in the 1980s (0.89, 95% confidence interval 0.81–0.94) compared with the recent 2015–2021 interval (0.52, 95% confidence interval 0.43–0.60). Declines of egg and shorebird abundance occurred shortly after horseshoe crab harvest reached its peak. Red knot aerial survey counts have stabilized at 30% of the baseline population while ruddy turnstone counts are 40% of baseline estimates. Initially these species were evenly distributed between the New Jersey and Delaware coasts but both species have trended toward predominately occupying New Jersey beaches. A lack of recovery of horseshoe crab egg and shorebird abundance suggests that horseshoe crab harvest management has stabilized populations but progress toward population recovery has been limited. Impacts from bycatch, the pharmaceutical industry and other potential population impacts must be better quantified and mitigated, if necessary, to promote the recovery of horseshoe crab populations. Measurements of horseshoe egg prevalence and abundance are essential metrics for tracking the progress toward management goals for improving shorebird habitat quality.

Evaluation of an Ergonomic Intervention Demonstrates Reduced Low Back Loads Associated With Commercial Dungeness Crab Harvesting

Evaluation of an Ergonomic Intervention Demonstrates Reduced Low Back Loads Associated With Commercial Dungeness Crab Harvesting

Population dynamics of mud crab, Scylla olivacea (Herbst, 1796) from the Sundarbans of Bangladesh

AbstractThe Sundarbans mangrove regions are the home of the mud crab (Scylla olivacea) business, as forest areas are potential places for random crab harvesting, trading, and exporting overseas seafood markets. Since the mud crab was being captured on a large‐scale in the wild for various purposes, estimation of population parameters were immediately done in terms of body weight and length‐frequency data collected from different locations in the forest of southwestern Bangladesh to understand the status of the stock. Recruitment pattern, growth parameters, mortality rates, and exploitation levels (E) were estimated to understand the population dynamics of S. olivacea. Asymptotic carapace widths (CW∝) were 14.70 and 14.18 cm, and growth co‐efficients (K) were 0.47 and 0.50 year–1 for male and female S. olivacea, respectively. The fishing mortalities were 2.32 and 1.13 year–1 and natural mortalities were 1.39 and 1.46 year–1 for males and females, respectively. Year‐round recruitment of this species takes place in the wild with a peak between June and November. The E for S. olivacea was found to be 0.63 for the male and 0.44 for the female. In summery, the stock of S. olivacea is found to be overexploited in the Sundarbans of Bangladesh. Therefore, mud crab resources should be taken into consideration under suitable fisheries management policies to conserve this national treasure in this delta. It is supposed that the findings will draw the attention of the scientists in the fields of aquatic biology, ecology, and management of the Sundarbans in restoring the mud crab population.

Life without ice: Perceptions of environmental impacts on marine resources and subsistence users of St. Lawrence Island

The Bering Strait region is undergoing rapid environmental change linked to reductions in the extent and seasonal availability of sea ice. The goal of the present study was to assess the impacts that environmental change and loss of sea ice has had on marine subsistence resources and resource users in the communities of St. Lawrence Island (SLI), Alaska. The broader research design was multidisciplinary in order to document any shifts in the abundance and health of key marine subsistence species, while recording people's perceptions of changing environmental conditions in their lifetime. The present study focuses on the perceived social and material effects of climate change on SLI residents. To capture human perceptions and experiences, open ended interviews were conducted during three weeks in April and May 2019, during which time 25 SLI residents were interviewed. Four main themes were assessed: 1) key marine resources for SLI communities, 2) perceptions about changes in key resources, 3) community responses to change, and 4) the future of the subsistence way of life in these communities. Interviews were transcribed, coded for themes, and analyzed using MAXQDA software. Results indicate the four most discussed marine resources were Pacific walruses (Odobenus rosmarus divergens), seals, crabs, and fish. The largest changes observed in these resources included: decreased walrus harvests and limited access with increased hunting effort; an increase in the abundance of Hanasaki crab (Paralithodes brevipes) and limited crab harvests due to lack of shorefast ice; and increasing abundances of walleye pollock (Gadus chalcogrammus) and Pacific cod (Gadus macrocephalus). SLI residents utilize a broad range of edible marine flora and fauna, and at times, eat less desirable prey items due to scarcity of preferred species. Lastly, most informants that discussed the future of a subsistence way of life, were concerned future generations will be harvesting and eating less subsistence resources. Due to environmental changes, and most specifically loss of sea ice, SLI communities may have to diversify the species that they harvest to continue maritime subsistence practices, or may turn to consuming more terrestrial and domestic sources of protein if available. To better understand resource availability and to manage for a changing ecosystem, resource managers and policy makers may: 1) anticipate a need for conducting stock assessments for king and Hanasaki crabs at regular intervals, 2) anticipate a need for conflict resolutions, mitigation frameworks, or agreements if commercial fishing vessels encroach on space and resources traditionally used by SLI subsistence users, and 3) take an active approach in obtaining authorizations for the harvest of currently protected marine mammals, which may be needed to ensure food security and consumption of historically traditional foods from the local environment.

Potential impact of harvesting on Tanner crab (&lt;i&gt;Chionoecetes bairdi&lt;/i&gt;) on state of its commercial stock off the coast of Kamchatka

Potential impact of landing on the stock and biological state of Tanner crab is analyzed for two fishery districts at Kamchatka in 2013-2020. In the Kamchatka-Kuril fishery subzone, the number of commercial males without limbs and with old shell increased in catches that may be associated with active operations of alive-crab vessels in 2015-2017. In the Petropavlovsk-Commander fishery subzone, cases of injured Tanner crabs catch became frequent after resumption of the crab harvesting in 2017, as well as the cases of commercial crabs with old shell, that also could be explained by operations of alive-crab vessels. The operations of such vessels are distinguished by strict sorting of caught crabs with removing the individuals of lower quality. As the result, the crabs without limbs and commercial males at late stages before molting were accumulated in the areas of sorting. The problem can be solved by measures for total registration (weighting) of catch before the start of sorting, concerning to all crabs with commercial size landed aboard. To avoid degradation of the Tanner crab population, development of catch processing aboard fishing vessels is recommended, with transportation of frozen products instead of live crabs.

Climate Extreme Seeds a New Domoic Acid Hotspot on the US West Coast

A heatwave that blanketed the northeast Pacific Ocean in 2013–2015 had severe impacts on the marine ecosystem through altered species composition and survival. A direct result of this marine heatwave was a sustained, record-setting harmful algal bloom (HAB), caused by the toxigenic diatom, Pseudo-nitzschia, that led to an unprecedented delay in harvest opportunity for commercial Dungeness crab (Metacarcinus magister) and closure of other recreational, commercial and tribal shellfish harvest, including razor clams. Samples collected during a cruise in summer 2015, showed the appearance of a highly toxic “hotspot” between Cape Mendocino, CA and Cape Blanco, OR that was observed again during cruises in the summers of 2016–2018. The transport of toxic cells from this retentive site northward during wind relaxations or reversals associated with storms resulted in economically debilitating delay or closure of Dungeness crab harvest in both northern California and Oregon in 2015–2019. Analyses of historic large-scale Pseudo-nitzschia HABs have shown that these events occur during warm periods such as El Niño, positive phases of the Pacific Decadal Oscillation, or the record-setting marine heatwave. In order to reduce the impacts of large-scale HABs along the west coast of North America, early warning systems have been developed to forewarn coastal managers. These early warning systems include the Pacific Northwest and California HAB Bulletins, both of which have documented elevated domoic acid and increased risk associated with the northern California hotspot. These early warnings enable mitigative actions such as selective opening of safe harvest zones, increased harvest limits during low risk periods, and early harvest in anticipation of impending HAB events. The aims of this study are to show trends in nearshore domoic acid along the US west coast in recent years, including the recent establishment of a new seed bed of highly-toxic Pseudo-nitzschia, and to explore how early warning systems are a useful tool to mitigate the human and environmental health and economic impacts associated with harmful algal blooms.

Harvesting strategies during a forecasted decline in the Newfoundland and Labrador snow crab fishery

A predicted and communicated decline in the Newfoundland and Labrador snow crab (Chionoecetes opilio) resource, the basis of the world’s largest snow crab fishery for two decades, has come to fruition. Given considerable lead time, this scenario creates an interesting dynamic to investigate how crab harvesters may have formed anticipatory behavioural responses to mitigate against the decline. In this analysis, economic, stock status, and vessel activity indicators are examined along with spatiotemporal fishing patterns before, during, and after the decline to assess harvester behaviour and fleet dynamics. We hypothesize that behaviours indicative of increased competition and a race to fish would emerge in response to the forecasted decline. Contrary to our expectations, we find no evidence of earlier or more rapid fishing, nor broader or more intense fishing patterns. Increased gear soak times were the most common adaptive response employed by harvesters, which were marginally successful in mitigating against declining catch rates and reducing discards. The majority of harvesters appeared to prosecute the fishery in a similar fashion as they historically had, and simply accepted reducing catch rates on known fishing grounds. Some historically dominant fishing grounds even became abandoned with little to no apparent adaptive responses by harvesters. Specific reasons for the general lack of behavioural adaptations to the forecasted fishery decline are unknown but are associated with an Individual Quota system, favourable product prices that have more than offset revenue losses from reduced catch, and small-scale management areas that may have rendered little or no capacity to develop adaptive strategies.

Effects of 3D seismic surveying on snow crab fishery

Commercial Snow Crab (Chionoecetes opilio) harvesters believe marine noise from seismic surveys reduces commercial Snow Crab catch rates. Depending on the type of seismic survey used, animals living in a particular area could be exposed to loud noise (e.g. daily Sound Exposure Level (SEL) >165 dB re 1 μPa2·s) for periods ranging from hours (typical 2D survey) to months (detailed 3D survey). This field experiment applied a series of comparisons conducted within a Before-After-Control-Impact study design to investigate the effect of prolonged industrial 3D seismic exposure on the catch rates of Snow Crab over nine weeks in 2017 and five weeks in 2018. Changes in catch rates at 3D seismic surveying sites were inconsistent across years, with reduced catches in 2017 and increased catches in 2018. Catch rates were similar at experimental and control sites within two weeks after exposure, and the potential effect of seismic surveying was not measured at a distance of 30 km. The large variation in catch rates across small temporal and spatial scales coupled with the absence of notable mechanistic responses of Snow Crab in past studies to seismic in associated snow crab movement behavior, gene expression and physiology, we conclude that the observed differences owing to seismic surveying in our study design are likely a result of stochastic processes external to our manipulation.

Mass Media Reporting and Illicit Harvesting of Russian Crab: Implications for Sustainable Fishery

Existing methods of combating the shadow economy do not always give reliable results. This is particularly true for the illegal use of renewable natural resources. In some parts of the Northwest Pacific basin, illegal, unreported, and unregulated (IUU) fishing has become an issue of growing concern for the sustainability of resource management, ecology, and the social environment. Many factors combine to produce these harmful phenomena. The complex legal rights for shared natural marine resources, the weak capacity of state institutions, and the lack of international cooperation between exporters and importers are all relevant. These factors can be eliminated by supplementing the “traditional” analysis of the shadow economy with new data mined from the media. For the crab harvesting regions of Russia, long-lasting benefits can be achieved through improvements in governance, accountability, and public awareness, or more specifically, through extensive mass media coverage of relevant topics. We argue that in the Russian Pacific, levels of illegal crab harvesting and smuggling correlates closely to the frequency of media references. The results suggest possible applications of mass media analysis: developing additional metrics for the dynamics of shadow economies; and the formulation of effective policy recommendations for sustainable fishing.

Using a participatory impact assessment framework to evaluate a community‐led mangrove and fisheries conservation approach in West Kalimantan, Indonesia

Abstract Community‐based conservation has been identified as a solution to biodiversity loss, climate change and the reduction of rural poverty. The heterogeneity in social and economic inequalities often acts as a barrier to community engagement in resource management and further inhibits the distributional equity of social and ecological outcomes. This study presents a participatory impact assessment (PIA) framework that evaluated the outcomes of a cross‐sector community‐led conservation initiative. Community members involved in the programme identified activities and outcomes for the conservation cooperative (CC), ranking the influence of the former on the latter as well as their daily life through multiple focus group discussions (FGDs). Participants were asked to rank the impact of activities on outcomes and the scale of the outcome which was totalled to identify the most impactful programme activities and outcomes during the project period. Community members reported improved income, health, education and the creation of a locally led natural resource management system. Members also reported improved crab harvest rates and reduced mangrove deforestation. Environmental outcomes identified by community members through the PIA were verified through a secondary spatial analysis and mud crab independent fisheries monitoring. The results support the hypothesis that environmental non‐governmental organizations (NGOs) need to consider a multi‐dimensional view of human well‐being, and that cross‐sector integrated interventions may be effective at improving multiple outcomes. Future steps should focus on spatial replication of the CC programme which will provide further insights by testing for differences in outcomes between villages, how those are impacted by pre‐existing social and ecological systems and comparing outcomes between control sites that did not receive interventions. A free Plain Language Summary can be found within the Supporting Information of this article.

Effects of 2D Seismic on Snow Crab Movement Behavior

Sound is an environmental feature that is used by a variety of marine taxa for feeding, reproduction, navigation and predator avoidance. Consequently, alterations to the soundscape have the potential to alter an individual’s behaviour, physiology and ultimately fitness. Furthermore, such responses have the potential to negatively influence commercial fishing interests. In Atlantic Canada, snow crab fishing and hydrocarbon extraction are billion dollar industries. Snow crab harvesters contend that seismic noise from hydrocarbon exploration has strong negative effects on catch rates; an issue that is likely to become more acute given that the species is currently in decline. As part of a collaborative, multi-disciplinary study conducted offshore on the continental slope, positioning telemetry was used from 2015-2017 in a Before-After-Control-Impact (BACI) study design to assess the behavioral responses of snow crab to exposure from industry seismic vessels. While effects of seismic exposure on snow crab movement could not be ruled out completely, effects were at most quite small relative to natural variation. In contrast, snow crab exhibited much clearer responses to handling, temperature and time of day. Overall, our results suggest that seismic effects, specific to the behavior of adult male snow crab, are at most subtle and are not likely to be a prominent threat to the fishery.