Fishery Closures Research Articles

Closing the life‐history loop: Density effects on fecundity and egg size of an exploited, amphidromous fish (Galaxias maculatus) in freshwater protected areas

AbstractUnderstanding how fecundity and egg size respond to density‐dependent and density‐independent processes is essential for fisheries assessments because it shows managers how exploited populations respond to fishery closures. Similarly, the extent to which density‐dependent and density‐independent processes influence fecundity and egg size in freshwater protected areas (FPAs) is important for determining their conservation potential and effectiveness as a fisheries enhancement strategy.The fecundity and egg size of 164 sexually matureGalaxias maculatusfemales collected from coastal waterways on the West Coast of New Zealand's South Island were determined from a combination of techniques. Specifically, the additive and interactive effects of density, temperature, and body size on fecundity and egg size were examined in 10G. maculatuspopulations across a density gradient mediated by fishery closures and tested for an egg size/fecundity trade‐off.There was no evidence of an egg size/fecundity trade‐off, or of negative density‐dependent effects on fecundity or egg size within FPAs. Egg size, gonadosomatic index, and water temperature were correlated with latitude.Fecundity increased with body size, but egg size did not. This highlights the importance of available forage (terrestrial‐ and stream‐based prey) forG. maculatusto maintain individual growth to increase egg production and larval export derived from no‐take FPAs.For the current network of no‐take FPAs to be more effective as a management tool, efforts should focus on the remediation of in‐stream and requisite riparian spawning habitats, the degradation of which has caused population bottlenecks for this culturally and economically important amphidromous species. The major subsidy from FPAs for theG. maculatusmetapopulation is sustainable egg production if migration to sea of the greatest possible number of larvae can be ensured.

Shelf break exchange processes influence the availability of the northern shortfin squid, Illex illecebrosus, in the Northwest Atlantic

AbstractThe United States Northern Shortfin squid fishery is known for its large fluctuations in catch at annual scales. In the last 5 years, this fishery has experienced increased availability of Illex illecebrosus along the Northeast US continental shelf (NES), resulting in high catch per unit effort (CPUE) and early fishery closures due to quota exceedance. The fishery occurs within the Northwest Atlantic, whose complex dynamics are set up by the interplay between the large‐scale Gulf Stream, mesoscale eddies, Shelfbreak Jet, and shelf‐slope exchange processes. Our ability to understand and quantify this regional variability is requisite for understanding the availability patterns of Illex, which are largely influenced by oceanographic conditions. In an effort to advance our current understanding of the seasonal and interannual variability in this species' relative abundance on the NES, we used generalized additive models to examine the relationships between the physical environment and hotspots of productivity to changes in CPUE of I. illecebrosus in the Southern stock component, which comprises the US fishery. Specifically, we derived oceanographic indicators by pairing high‐resolution remote sensing data and global ocean reanalysis physical data to high‐resolution fishery catch data. We identified a suite of environmental covariates that were strongly related to instances of higher catch rates. In particular, bottom temperature, warm core rings, subsurface features, and frontal dynamics together serve as indicators of habitat condition and primary productivity hotspots, providing great utility for understanding the distribution of Illex with the potential for forecasting seasonal and interannual availability.

Effects of a fishery closure and prey abundance on seabird diet and breeding success: Implications for strategic fisheries management and seabird conservation

Industrial forage fish fisheries may reduce prey availability affecting diet and breeding success of marine predators. However, evidence for fisheries effects on predator demography remains rare, hindering evaluation of their impact on populations. Using 25 years of data on the commercial lesser sandeel fishery in the north-western North Sea, we evaluated the effectiveness of the closure in safeguarding breeding success of four seabird species - black-legged kittiwake, common guillemot, Atlantic puffin and razorbill. We also tested for effects of a scientific fishery in the closed area on breeding success. We quantified how changes in the diet of chicks for the four seabird species were influenced by the abundance of sandeels and the alternative prey species, European sprat, and the potential prey behavioural disturbance effects of sandeel fishing on the prey. Finally, we examined how changes in chick diet and prey abundance have shaped long-term variation in seabird breeding success. The period of fishery operation was associated with a decline in kittiwake breeding success in colonies with foraging ranges overlapping the closed area, from 52 % of young fledged pre-fishery to 23 % during fishery operation. Breeding success increased by approximately 10 % in the period following fishery closure to 2018. We document wide uncertainty around this increase in breeding success, partly driven by variation in the responses of individual colonies. For guillemot, razorbill and puffin we found no evidence for negative effects of the fishery on breeding success, nor for positive effects arising from its closure. We found no evidence for an impact on breeding success of the scientific fishery. The proportion of sandeel in chick diet was positively associated with breeding success in the four species, albeit with only weak evidence for puffin. Fishing effort was associated with a decreased proportion of sandeel in puffin diet, a lower proportion of the sandeel component of the diet consisting of 0-group in kittiwake, razorbill and puffin, and with decreased kittiwake breeding success. Our findings provide quantitative evidence for how forage fish fisheries may impact seabird demography, highlighting the species-specific nature of responses, and the difficulties in teasing apart drivers amongst ongoing environmental change. Time-area fisheries closures show promise as a tool for positively affecting productivity in some seabird species. However, we identify important caveats around its effectiveness for strategic seabird conservation and aspirations of net gain.

Effects of seasonal spawning closures on pike (Esox lucius L.) and perch (Perca fluviatilis L.) catches and coastal food webs in the western Baltic Sea

Marine protected areas have become one of the main tools in the battle to curb marine biodiversity loss and habitat degradation. Yet, implementation of permanent fishery closures has often generated resource user conflicts that ultimately undermine conservation goals. Here we assessed the influence of an alternative and often more accepted measure – seasonal fish spawning closures – on large predatory fish and coastal food webs in the western Baltic Sea (Sweden). In spring 2017, we conducted a multivariable field survey in 11 seasonal closures and 11 paired references areas open to fishing. In each area, pike was sampled through angling, and perch and mesopredators through gillnet surveys. To assess trophic cascades, we measured zooplankton abundance and loss of tethered gammarids from predation. Catches per unit effort of northern pike (Esox lucius) – the main target species in recreational fisheries – were ca. 2.5 times higher per unit effort in closures than reference areas; an effect that may be caused by higher abundance and/or higher catchability of pike in the absence of fishing. Catch and weight per unit effort of the more common predator European perch (Perca fluviatilus), and the mesopredators roach (Rutilus rutilus) and three-spined stickleback (Gasterosteus aculeatus) in survey nets were, however, unaffected by closures. Moreover, a previously hypothesized trophic cascade from perch to zooplankton via three-spined stickleback was supported by the analyses, but appeared independent of closures. Yet, predation risk for tethered gammarid amphipods (a prey of stickleback and an important grazer on macroalgae) was three times higher in fished areas than in closures; a cascading closure effect that may potentially be caused by small predatory fish being less active in protected areas to avoid pike predation. Overall, our results suggest that spawning closures impact pike abundance and/or behavior and could help limit the effects of fishing, but that more research is needed to disentangle i) what mechanism(s) that underlie the protection effect on pike catches, ii) the apparently weaker closure impacts on other fish species, as well as iii) the potential for cascading effects on lower trophic levels. Therefore, new seasonal spawning closures should be implemented in addition to (and not instead of) much-needed permanent closures, which have well-known effects on the wider ecosystem.

Local Perspectives Matter: The Case of the Seasonal Fishery Closure in the Visayan Sea, Philippines

This study examines the knowledge, perceptions, and compliance of fisheries stakeholders with the seasonal fishery closure implemented in the Visayan Sea, Philippines. We interviewed 235 municipal fisheries stakeholders composed of municipal fishers, fish dryers, fish traders/fish brokers (regulated group) and local government units, Philippine National Police-Maritime Group/Philippine Coast Guard, and fish wardens (regulator group) in 12 coastal towns surrounding the Visayan Sea. Data from interviews were complemented by focus group discussions. Overall, municipal fisheries stakeholders have a fair knowledge about the SFC. The regulated group in the municipalities within Panay Island are more knowledgeable about the SFC compared to their counterparts in other areas. There is a positive correlation between the regulated group’s knowledge and perceptions about, and compliance, with the SFC. The lack of alternative livelihoods, uneven implementation of the SFC and poverty also influence compliance. Given our findings, addressing these factors is crucial to effective fisheries management.

An evidence-based approach for selecting a limit reference point for Pacific herring (Clupea pallasii) stocks in British Columbia, Canada

A limit reference point (LRP) is defined as a level of biomass to be avoided with high probability, which should be selected to protect fish stocks from “serious harm”. We present an evidence-based approach for diagnosing serious harm and apply it to the selection of LRPs for five Pacific herring ( Clupea pallasii) stocks in British Columbia (BC). Natural mortality ( M) is estimated to be time varying and has increased more than it declined over the past three decades, which presents a challenge for estimation of equilibrium reference points based on maximum sustainable yield. We present a semi-empirical approach for developing LRPs, which examines surplus production in relation to spawning biomass to determine whether there is evidence for low productivity, low biomass (LP-LB) states consistent with serious harm. Three stocks showed evidence of persistent LP-LB states that resulted in periods of fishery closures. Based on these results, an LRP of 30% of unfished spawning biomass (0.3 B0) was recommended and adopted for management of all five major stocks of BC Pacific herring.

Pacific Salmon Strategy Initiative will conserve marine birds with fishery closures and gillnet license retirements

Due to their lack of selectivity, entanglement of marine birds, along with a wide range of other species, in gillnets is a conservation issue worldwide. In Pacific Canada, mortality from incidental take in salmon gillnet fisheries has been identified as one of the largest sources of human-induced mortality for marine diving birds, a conservation concern impacting both local breeders and visiting migrants. In 2021, to address historic declines in Pacific salmon populations, Fisheries and Oceans Canada introduced the Pacific Salmon Strategy Initiative (PSSI). The PSSI is transformative and includes long-term commercial closures and a license retirement program. The PSSI will move the fishery away from gillnets towards more selective fishing methods with lower release mortality of non-target salmon species. Gillnet fishery closures and license retirements related to new policies under the PSSI will reduce entanglement mortality of migratory marine birds and species at risk from Canada and elsewhere, as a significant conservation byproduct. Closures and license retirements are the most effective tools to reduce bird entanglement mortality in gillnets because of the lack of technical solutions to reduce bycatch and the challenges to fund and develop robust, long-term, interdepartmental monitoring programs to inform the management of incidental take.

Small-scale octopus fishery operations enable environmentally and socioeconomically sustainable sourcing of nutrients under climate change.

Small-scale octopus fisheries represent an underexplored source of nutrients and socioeconomic benefits for populations in the tropics. Here we analyse data from global seafood databases and published literature, finding that tropical small-scale octopus fisheries produced 88,000 t of catch and processed octopus in 2017, with a landed value of US$ 2.3 billion, contributing towards copper, iron and selenium intakes, with over twice the vitamin B12 content of finfish. Catch methods, primarily consisting of small-scale lines and small-scale pots and traps, produced minimal bycatch, and the fast growth and adaptability of octopus may facilitate environmentally sustainable production under climatic change. Management approaches including periodic fishery closures, size restrictions, licences and knowledge transfer of fishing gears can enable greater blue food supply and economic value to be generated while improving environmental sustainability.

Drivers of Atlantic herring decline and evidence basis for fisheries closures and rebuilding plans

Atlantic herring ( Clupea harengus) are economically and ecologically significant but have been in decline in Atlantic Canada due to an uncertain combination of environmental recruitment controls, predation, and fishing (commercial fishery and poorly documented bait removals). Fisheries and Oceans Canada partially closed Atlantic mackerel ( Scomber scombrus) and herring fisheries in March 2022 amid controversy and disagreement. Here, we develop a conceptual model for natural and anthropogenic controls on herring abundance centered on the southern Gulf of St. Lawrence (sGSL) and evaluate the likely importance of each. We provide the first estimates of the magnitude of bait fishery withdrawals in the sGSL. The decline in sGSL herring is likely driven by natural predation exacerbated by fishing. Bait fishery removals were 182 tonnes in 2021, suggesting that previous estimates for removals of spring-spawning herring were ∼30% too low. Fisheries closure is consistent with a precautionary approach given uncertainties and irreversibility of stock collapse. Ecosystemic models are needed but will be difficult to develop given the incomplete understanding of prey substitutability and net effect of interacting environmental processes.

Closed Season Policy Is Only Partly Practiced in Surigao del Sur, Philippines

Small-scale fisheries (SSF) make a critical contribution in terms of employment and food security to coastal communities. Fish serves multiple purposes, mainly as a cheap source of protein and minerals for lower-income families. In order to help sustain this demand and to protect fishing resources, the closed season policy, temporal closure, and spatial closure were adopted to protect fish stocks and avoid fishery collapse. To assess the agreement and compliance of the three municipalities (Cortes, Lanuza, and Lianga) in Surigao del Sur to this policy, we surveyed their responses regarding this policy. We used focus group discussions, two focus groups per municipality (N = 80), followed by member checking to gather and clarify the data from six barangays with small-scale fishers (N = 192). The findings indicate that each community in the three municipalities studied have a different method of implementing the fishery closure or closed fishing season policy which resulted in a limited conservation impact on fish stocks. In the municipality of Cortes, 92% agreed with the policy, provided there would be enough money to comply with the policy. In Lanuza, 60% agreed to implement the policy, provided there would be alternative jobs available. In contrast, the municipality of Lianga, which did not implement this policy, had only 4% that agreed to impose the policy to restore depleted fish stocks. Other reasons for not implementing a closed season policy include lack of community organization, poor fishery management, and lack of strong government support for the policy. Moreover, fishers were only willing to stop fishing if they were given a subsidy of PHP 15,000 per month. In the long term, fishers who provide fish protein needs for the nation also need help and attention from policy and decision makers to realize sustainable fisheries.

Revenue loss due to whale entanglement mitigation and fishery closures

Whale entanglements with fishing gear, exacerbated by changing environmental conditions, pose significant risk to whale populations. Management tools used to reduce entanglement risk, for example temporary area restrictions on fishing, can have negative economic consequences for fishing communities. Balancing whale protection with sustaining productive fisheries is therefore a challenge experienced worldwide. In the California Current Ecosystem, ecosystem indicators have been used to understand the environmental dynamics that lead to increased whale entanglement risk in a lucrative crab fishery. However, an assessment of socio-economic risk for this fishery, as in many other regions, is missing. We estimate retrospectively the losses from ex-vessel revenue experienced by commercial Dungeness crab fishers in California during two seasons subject to whale entanglement mitigation measures using a Linear-Cragg hurdle modeling approach which incorporated estimates of pre-season crab abundance. In the 2020 fishing season, our results suggest total revenues would have been $14.4 million higher in the Central Management Area of California in the absence of closures and other disturbances. In the 2019 fishing season, our results suggest ex-vessel revenues would have been $9.4 million higher in the Central Management Area and $0.3 million higher in the Northern Management Area. Our evaluation should motivate the development of strategies which maximize whale protection whilst promoting productive, sustainable and economically-viable fisheries.

A draft reference genome of the red abalone, Haliotis rufescens, for conservation genomics.

Red abalone, Haliotis rufescens, are herbivorous marine gastropods that primarily feed on kelp. They are the largest and longest-lived of abalone species with a range distribution in North America from central Oregon, United States, to Baja California, MEX. Recently, red abalone have been in decline as a consequence of overharvesting, disease, and climate change, resulting in the closure of the commercial fishery in the 1990s and the recreational fishery in 2018. Protecting this ecologically and economically important species requires an understanding of their current population dynamics and connectivity. Here, we present a new red abalone reference genome as part of the California Conservation Genomics Project (CCGP). Following the CCGP genome strategy, we used Pacific Biosciences HiFi long reads and Dovetail Omni-C data to generate a scaffold-level assembly. The assembly comprises 616 scaffolds for a total size of 1.3 Gb, a scaffold N50 of 45.7 Mb, and a BUSCO complete score of 97.3%. This genome represents a significant improvement over a previous assembly and will serve as a powerful tool for investigating seascape genomic diversity, local adaptation to temperature and ocean acidification, and informing management strategies.

Cuttlefish conservation: a global review of methods to ameliorate unwanted fishing mortality and other anthropogenic threats to sustainability

Abstract Cuttlefish are an important global fisheries resource, and their demand is placing increasing pressure on populations in many areas, necessitating conservation measures. We reviewed evidence from case studies spanning Europe, Africa, Asia, and Australia encompassing diverse intervention methods (fisheries closures, protected areas, habitat restoration, fishing-gear modifications, promoting egg survival, and restocking), and we also discuss the effects of pollution on cuttlefish. We conclude: (1) spatio-temporal closures need to encompass substantial portions of a species’ range and protect at least one major part of their life cycle; (2) fishing-gear modifications have the potential to reduce unwanted cuttlefish capture, but more comprehensive trials are needed; (3) egg survival can be improved by diverting and salvaging from traps; (4) existing lab rearing and restocking may not produce financially viable results; and (5) fisheries management policies should be regularly reviewed in light of rapid changes in cuttlefish stock status. Further, citizen science can provide data to reduce uncertainty in empirical assessments. The information synthesized in this review will guide managers and stakeholders to implement regulations and conservation initiatives that increase the productivity and sustainability of fisheries interacting with cuttlefish, and highlights gaps in knowledge that need to be addressed.

Reflecting on 25 years of quota management in a spiny lobster fishery: Lessons learned from a harvest strategy perspective

The Southern Zone rock lobster fishery of South Australia has been managed by individual transferable quotas since 1993, with annual catch limits set using harvest strategy decision rules. This work describes the performance of strategies over 25 years focusing on challenges experienced during periods of poor fishery recruitment. Early strategies identified indicators and performance ranges for the fishery but lacked detail on required management action when reference points were breached. Between 2002 and 2009, the fishery experienced a considerable decline in recruitment resulting in catch rate, the primary indicator, decreasing by 70%. The harvest strategy in place failed to reduce catch levels appropriately and despite consecutive years of decreasing catch rate, was unable to arrest the fishery decline. Explicit harvest control rules for quota setting were developed in 2010 and refined in both 2014 and 2019, with the specific focus of ensuring sustainability and rebuilding lobster biomass. Application of these strategies have been successful at achieving this objective, most notably since 2015. The study highlights that harvest strategies must include control rules that respond rapidly to recruitment declines. Specifically, based on harvest strategy testing and evaluation, required levels of quota reduction should be clearly defined. In combination with limit reference points that mandate the point of fishery closure, metarules and quota caps that promote biomass increase, such strategies serve to meet fishery objectives and ensure sustainability.

Socioeconomic disruptions of harmful algal blooms in indigenous communities: The case of Quinault Indian nation

Harmful algal blooms (HABs) have been a pervasive challenge across coastal communities of the U.S. West Coast in recent years negatively affecting local economies and livelihoods. We focus on the effects of HABs to the Quinault Indian Nation (QIN) triggered by Pseudo-nitzschia that produce the toxin domoic acid (DA). This toxin accumulates in filter feeders and poses threats to human health via shellfish consumption. Consumption of razor clams with high levels of DA and Dungeness crab that prey on them can cause amnesic shellfish poisoning in humans and therefore requires closure of commercial, recreational and subsistence fisheries, postponing or limiting harvesting seasons. These disruptions result in significant losses in revenues along with negative effects to sociocultural dimensions of key importance to coastal communities. Livelihoods and wellbeing of tribal communities are affected disproportionately due to higher vulnerability and reliance on these marine resources for subsistence. We assess these effects at multiple levels for the QIN and discuss and reflect, through a tribal lens, upon advances and opportunities for impact mitigation and adaptation in the face of HABs, along with persisting challenges.

Perceptions of compliance in recreational fisheries: Case study of the Peel-Harvey blue swimmer crab fishery

Effective recreational fisheries management requires a balance between fisher enjoyment and compliance with regulations and fisher perceptions can be useful to understand whether the balance is right. Our study collected fisher insights via an online perceptions survey into compliance within the recreational shore-based Peel-Harvey blue swimmer crab fishery in Western Australia. Overwhelmingly, participants self-reported as complying with regulations; a positive finding for a licence-free fishery. Further, to enable increased quantity and size of available stock and thus overall enjoyment of the fishery, survey participants suggested longer fishery closure periods; harsher noncompliance penalties; more natural and physical surveillance; and greater educational signage in popular fishing areas. These insights challenge existing literature whereby tough regulations are often rejected by fishers and may lead to noncompliance. In a view to achieve a shared goal of a sustainable fishery, we explore survey perceptions against situational crime prevention to optimize compliance, embracing regulator-led ‘cooperative compliance’ outcomes. Our results are useful not only to this fishery but apply more broadly to other fisheries within and beyond Western Australia.

Impacts of Recreational Angling on Fish Population Recovery after a Commercial Fishing Ban

It is often assumed that recreational fishing has negligible influences on fish stocks compared to commercial fishing. However, for inland water bodies in densely populated areas, this assumption may not be supported. In this study, we demonstrate variable stock recovery rates among different fish species with similar life histories in a large productive inland freshwater ecosystem (Kaunas Reservoir, Lithuania), where previously intensive commercial fishing has been banned since 2013. We conducted over 900 surveys of recreational anglers from 2016 to 2021 to document recreational fishing catches and combined these catch estimates with drone and fishfinder device-based assessments of recreational fishing effort. Fish population recovery rates were assessed using a standardized catch-per-unit-effort time series in independent scientific surveys. We show that recreational fishing is slowing the recovery of predatory species, such as pikeperch Sander lucioperca (Linnaeus, 1758) and Eurasian perch Perca fluviatilis Linnaeus, 1758. The estimated annual recreational catches for these species were 19 tons (min-max of 7–55 tons) and 9 tons (4–28), respectively, which was considerably higher than the average commercial catch before the fishery closure (10 and 1 tons, respectively). In contrast, the recovery of roach Rutilus rutilus (Linnaeus, 1758), rarely caught by anglers (annual recreational catch of ca 3 tons compared to ca 100 tons of commercial catch), has been rapid, and the species is now dominating the ecosystem. Our study demonstrates that recreational fishing can have strong and selective impacts on fish species, reduce predator abundance, alter relative species composition and potentially change ecosystem state and dynamics.

Detecting endangered pinto abalone (Haliotis kamtschatkana) using environmental DNA: Comparison of ddPCR, qPCR, and conventional diver surveys

AbstractAbalone populations along the Pacific Coast of North America are threatened. In the Salish Sea (Washington, USA), pinto abalone (Haliotis kamtschatkana) have failed to recover from intensive harvest after over 25 years of fishery closure, prompting a growing restoration effort. As these efforts expand, a persistent challenge is simply locating this rare and highly cryptic species in the field, limiting the ability to identify critical habitat and locate wild adults to serve as restoration broodstock. Here, we tested the use of environmental DNA (eDNA) to detect pinto abalone. Using a quantitative PCR (qPCR) assay previously developed for larval pinto abalone, we first evaluated its sensitivity to abalone eDNA in aquaria settings, finding a positive relationship between abalone biomass and the concentration of abalone DNA. We then tested abalone eDNA detection in the field by collecting replicate water samples from abalone restoration sites, using an occupancy model to estimate detection probability in relation to abalone biomass estimated via diver surveys. Both eDNA concentration and detection probability were positively associated with diver‐estimated abalone biomass. By modifying the assay for droplet digital PCR (ddPCR), detection probability increased by 32%–89% over qPCR. eDNA surveys using ddPCR had higher error (CV = 96.9%) than diver surveys (CV = 29.4%) but were more efficient, taking approximately 1/10th of the person‐hours per site of a diver survey. For the final phase of the study, we collected water samples at 80 sites throughout the region, obtaining positive abalone eDNA detections at 11 sites with qPCR and 19 additional sites with ddPCR. Our results provide novel survey data on abalone populations within the Salish Sea and show that eDNA is a viable tool for cost‐effective, efficient, and non‐invasive abalone detection.

Advances in the use of nighttime light data to monitor and assess coastal fisheries under the impacts of human activities and climate and environmental changes: A case study in the Beibu Gulf

Nighttime light remote sensing has attracted increasing attention in fishery management due to its unique advantages in observing light fisheries. NASA's Black Marble product suite (VNP46A1) and Luojia 1–01 images are the latest nighttime light data with improved spatial and temporal resolutions. This paper developed an effective night-light fishing boat (NLFB) dataset to monitor and assess the coastal light fisheries in the Beibu Gulf. Daily NLFB data from 2018 to 2020 were used to map the spatiotemporal variations in fishing intensity, number of fishing boats and locations of core fishing areas. The influencing mechanisms of climate and environmental changes, fishery closures, COVID-19 and typhoons on the temporal and spatial variations in light fisheries were evaluated and discussed. Combined with the fishery boundaries defined by the China-Vietnam bilateral agreements, nighttime light remote sensing revealed the effective management of and restrictions on (such as fishery closures and lockdowns) fishing activities in the Chinese fishery area. The Vietnamese fishery area was under higher fishing pressure, especially in densely populated estuaries where the fish spawn and feed. Therefore, a cross-regional marine protected area (MPA) is recommended as a realistic strategy for the sustainable management of light fisheries in the Beibu Gulf. Nighttime light remote sensing provides a useful opportunity to combat illegal, unreported and unregulated (IUU) fishing in the future.

Biliary Polycyclic Aromatic Hydrocarbon Metabolite Equivalents Measured in Fish and Subtidal Invertebrates Following the Refugio Beach Oil Spill.

Monterey formation crude oil spilled from an onshore pipeline and entered the surf zone near Refugio State Beach, Santa Barbara County, CA, USA on 19 May 2015. Exposure to nearshore fish was evaluated by measuring biliary polycyclic aromatic hydrocarbon (PAH) metabolite concentrations in surfperch (Embiotocidae), collected near the release point, at a lesser oiled area, Gaviota State Beach, and near the Coal Oil Point oil seep, Campus Point, at both four days and approximately one year after the oil spill. Three to four weeks after the spill, fish, invertebrates, and kelp were collected near the same three sites for PAH analysis of edible tissues to support the fishery closure assessment. Additionally, thirteen days after the spill, vegetation, and invertebrate tissue samples from the seafloor near Refugio State Beach were analyzed for PAHs. In surfperch bile, mean naphthalene, phenanthrene and benzo(a)pyrene metabolite equivalents were significantly higher at Refugio State Beach, compared to Gaviota State Beach or Campus Point in 2015. One year later, there was no significant difference between the three sites. Spatial and depth zone patterns of PAH tissue concentrations from composited invertebrate, vegetation and fish showed highest concentrations were measured in invertebrates collected near Refugio State Beach. Overall, results show elevated PAH levels in nearshore organisms and provide a useful reference for potential PAH exposures in fish and subtidal invertebrates following a large nearshore oil spill.