Freshwater biodiversity is under pressure from the detrimental effects of climate change, habitat degradation, biological invasion, and overfishing. Environmental DNA (eDNA) obtained directly from environmental samples can be used to evaluate the distribution of aquatic species. We developed a new set of universal PCR primers (16 S 200) for eDNA metabarcoding from mitochondrial DNA sequences. Using

Accurate stock assessments are the basis of adequate fisheries management. In the Southwest Atlantic, fisheries of the Lane snapper (Lutjanus synagris) have been growing in importance in the last decades, following declines in other snapper fisheries since the late 1970 s, with evidence of overexploitation accumulating since the mid-2000 s. Contrasting environmental conditions along the area are potential

Electrical pulse fishing has been widely adopted by Dutch fishers as an economically viable alternative to tickler-chain trawling for common sole (Solea solea) in the North Sea. Concerns exist, however, that the use of electrical pulses may cause spinal injuries and haemorrhages, as previously shown for Atlantic cod (Gadus morhua). To find out whether other gadoids are similarly affected, we studied

Fish captured and released by recreational anglers are often exposed to air to enable hook removal and for admiration (e.g., photography). It is necessary to identify thresholds for air exposure that minimize sublethal alterations to inform best practice guidelines yet doing so in ecological-relevant field settings is challenging. We developed a novel attachment method for tri-axial accelerometer and

Targeting tunas associated with drifting Fish Aggregating Devices (dFADs) raises questions on the sustainability of tropical tuna fisheries. To limit catches of juvenile tunas, multiple time-area dFADs-fishing moratoria have been implemented by ICCAT since 1998. In this study we assessed the effectiveness of two different dFADs time-area closures implemented for the protection of both bigeye and yellowfin

There is interest in stock enhancement to support fisheries for California halibut Paralichthys californicus, a regionally important yet depleted species in the Southern California Bight (SCB), U.S. A quantitative model was developed to assess the cost of increasing harvestable California halibut in the SCB via releases of cultured juveniles. Reduced post-release survival of cultured juveniles was

A new model for estimation of daily probability for the Pacific saury (Cololabis saira) encounter was proposed. The model performance was tested for the period of 2004–2018 (August–November) using the data from the Russian vessel monitoring system. The following physical oceanographic variables were used for encounter probability prediction: the absolute values and gradients (∇) of speed (V) of passive

Small-scale fisheries in Italy account for around 70% of the total fishing fleet, as well as nearly 30% and 55% of capture-fisheries revenues and employment, respectively. Yet, the sector is experiencing a deep crisis, mostly due to reduced catches and to the consequent decrease in revenues. At the same time, a lack of socio-economic data is hampering an effective resource management and the identification

Phenotypic variation of Scomberomorus brasiliensis otoliths was evaluated by testing the null hypothesis of a single stock across the southwestern Atlantic Ocean. Otolith sampling of S. brasiliensis (n = 396) took place between July and October 2019 at nine locations along the Brazilian coast. The shape of each otolith contour was assessed with elliptic Fourier descriptors (EFDs) and their variation

Ocean acidification can influence the formation, development and functions of calcified structures in marine organisms, such as otoliths, which are mainly composed of calcium carbonate (CaCO3) and function in orientation, balance, sensory perception and locomotion in fish. This study investigated the impacts of seawater acidification (pH 8.10, 7.70 and 7.30, roughly corresponding to the ocean acidification

The brown shrimp Crangon crangon is the target species of one of the largest crustacean fisheries in the North Sea, producing considerable amounts of bycatch every season. Mortality rates of bycaught juveniles have traditionally been considered negligible, but this assumption was based on studies with short haul durations and short observation times. We investigated shrimp mortality due to trawling

Balanced harvest (BH) refers to applying moderate fishing pressure across a broad range of species, trophic levels (TL), stocks, or sizes in an ecosystem in proportion to productivity (gross production per biomass unit) or production (total cumulated biomass over a given period) instead of exerting pressure on particular taxa or sizes. Both modelling and empirical studies have shown that BH can lead

With the rapid growth of grey seal (Halichoerus grypus) population in the Baltic Sea, seal-induced catch losses have increased dramatically in coastal fisheries. There have been various attempts to mitigate these damages, such as modification of fishing gear, but solutions have proven inadequate. Promising research results have recently been obtained by using acoustic deterrent devices (ADDs) to keep

Atlantic herring (Clupea harengus; hereafter herring) is a forage fish that transfers energy from lower to higher trophic levels and sustains high-volume fisheries in the North Atlantic. This study aims to improve our understanding of the ecology of Newfoundland herring and its vulnerability to climate change by identifying key prey items and describing adult herring feeding strategies. We compared

Giant trevally (Caranx ignobilis, GT) are growing in popularity as a target for tourism-based recreational fisheries throughout their range in the Indo-Pacific. Although predominately catch-and-release (C&R), to date there is no species-specific scientific evidence to support capture and handling guidelines. As such, we examined how GT caught via fly fishing gear while in shallow water responded to

The harvest control rules for many fish and invertebrate stocks, managed using stock assessments based on fitting population dynamics models to monitoring data, rely on biological reference points. These reference points are often related to unfished conditions (‘B0’) and are calculated assuming that biological parameters and their associated functional forms (e.g., unfished recruitment (‘R0’), natural

Squid and cuttlefish are valuable UK commercial fisheries and anecdotal evidence suggests recreational fisheries for these species is rapidly emerging. Though the quantity captured by this sector is uncertain, recent updates to the sea angling diary has identified 36 records from two squid species from England, Scotland, and Wales in 2021. We suggest data are needed from recreational anglers to help

Understanding what causes large year classes and predicting them has been called the holy grail of fisheries science, one of the last great unanswered questions. Recruitment prediction, or forecasting, is an important component for setting fishery catch limits. We propose a new approach, called the “poor-recruitment paradigm”, for predicting recruitment using environmental variables. This approach

Ecosystem Based Fisheries Management aims to broaden the set of factors included in assessments and management decision making but progress with implementation remains limited. We developed a framework that examines the consequences of temporal changes in temperature and ocean pH on yield and profit of multiple interacting stocks including eastern Bering Sea (EBS) snow, southern Tanner, and red king

Yellowfin sole (Limanda aspera) is an abundant, commercially harvested flatfish that ranges across the northern and southeastern Bering Sea continental shelf. In recent years, the summer bottom trawl survey of the southeastern Bering Sea (SEBS) conducted by the National Marine Fisheries Service’s Alaska Fisheries Science Center (AFSC) extended into the northern Bering Sea (NBS) in August. This opportunity

Identifying fish spawning aggregations is crucial to determine effective fisheries management measures and protect key reproduction sites. We found direct evidence (the presence of post-ovulatory follicles) of a spawning aggregation of cubera snapper (Lutjanus cyanopterus) within the largest multiple-use marine protected area in southeastern Brazil, representing the first in-situ validation of a cubera

Rockfishes (Sebastes spp.) and the fisheries they support along the northeastern Pacific Ocean have undergone dynamic changes over the last century. The unique life history traits of rockfishes pose a host of challenges that make them difficult to monitor and susceptible to overfishing. Previous research has demonstrated that fishers’ knowledge and scientific data can help to create a more complete

The European Fish Ageing Network (EFAN) funded by the European Union, is reviewed, and assessed after a 20-year hiatus. The large number of scientists and technicians involved in this independent and informal network, and the time invested (four years), provided a significant advance in fish age estimation and methodologies. The results presented are based on two survey questionnaires sent to EFAN

Fisheries stock assessments increasingly account for size-dependence in natural mortality rates, usually by modeling mortality as a power function of body length. Various empirical studies have indicated a scaling of mortality with length in the range of − 0.84 to − 1.11, but substantially different scaling exponents ranging from − 0.75 to − 1.5 have been proposed on theoretical grounds or derived

The survival and injuries of wild Atlantic salmon released by coastal fishers from pontoon traps was examined in the early summer of 2020 in the Gulf of Bothnia in the northern Baltic Sea. A total of 491 salmon caught with pontoon traps was tagged with dart tags. By the end of December 2020, a total of 62 tag recoveries (13%) were received. Sixty-two per cent of the tag recoveries were obtained from

This paper describes, for the first time, that scallops can be attracted into static fishing gear using LED lights. This novel finding presents an opportunity for the development of a new, low impact fishing method for scallops. Traditionally, wild caught scallops are primarily fished using dredges and trawls. Due to their penetrative nature, the interaction of this towed gear with the seabed can cause

Siargao Island Protected Landscape and Seascape (SIPLAS) has an extensive mangrove area that supports marine biodiversity. This study documented mangrove fishes in three selected sites using a fishery-dependent survey approach, with samples taken by commissioned fishing or landed catch by local fishermen. A total of 129 species belonging to 38 families were documented and identified in the study. Dapa

Fatty acids play important role in several biological processes taking place in crustaceans, such as reproduction and molting. The aim of the current study is to evaluate the seasonal variation in fatty acid concentration and profile in crab species Ucides cordatus exploited in Brazilian mangroves. Eight samplings were performed throughout one year and 30 adult specimens - 15 males and 15 females -

Two hypotheses were tested concerning the consequences to adult sockeye salmon (Oncorhynchus nerka) of escape from commonly used fishing gear (gillnet, seine net and tangle net). First, by experimentally exposing 214 fish to three commonly used fishing gear types (gillnets, tangle nets, or seine nets) and releasing to complete migration after PIT-tagging, we tested the hypothesis that migration success

To better understand anthropogenically induced shifts of lake nutrient dynamics and subsequent consequences for fish and their zooplankton food sources, an increased spatial and temporal resolution of zooplankton monitoring data is needed. The Zooscan, an instrument mainly used in marine research, enables digitalization of zooplankton samples, and thereby substantially decreases the effort for zooplankton

In the Baltic Sea, the large predatory fish northern pike (Esox lucius L.) is important for both recreational fisheries and ecosystem functioning. As existing fishery-independent surveys do not adequately monitor pike populations, a general lack of knowledge on population status and trends poses challenges for management. Here we use recreational angling data as an alternative method to describe pike

European plaice (Pleuronectes platessa) is a key species in commercial fisheries in the North Sea, Skagerrak, Kattegat, and Baltic Sea. The reformed European Union Common Fisheries Policy includes the possibility of exemptions from the landing obligation for “species for which scientific evidence demonstrates high survival rates”. Discard survival from set-net fisheries is poorly studied. Trials were

Catch monitoring during demersal trawling is important to help fishers around the globe to cope with high bycatches. Information about catch composition during towing will allow fishers to identify and react to the presence of unwanted catch and undertake actions to avoid them during trawling. In demersal trawl fisheries, catch monitoring by the optical devices is typically challenged by the poor quality

The density and mean size of 0 + pikeperch (Sander lucioperca) were studied in late summer in 2004–2017 in clay-turbid and eutrophic Lake Tuusulanjärvi in southern Finland. Hydroacoustics and simultaneous experimental trawling were used to estimate the density of 0 + pikeperch. In some autumns, 0 + pikeperch was the most abundant species in the pelagic fish assemblage. However, the annual amplitude

Several studies have shown that the school type at release can significantly influence the amplitude of the movements of a tagged fish. In particular, it has been shown that seamounts can have a retention effect on tuna, suggesting that their migration patterns may differ significantly depending on the school type at release. However, many tuna releases near well-recognised mid-Atlantic seamounts have

Sampling designs for collection of shark size composition data are needed to fill one of the primary knowledge gaps hampering management of shark fisheries in Central America. These designs need to be tailored towards multi-species fisheries with highly structured landings, which are driven by buyer demand in port. In addition, due to the difficulty of maintaining catch quality outdoors in a tropical

Sustainable catch-and-release fisheries are based on the assumption that most fish survive an angling event. The adoption of best practices has become important to help mitigate post-release injury, behavioral impairment and mortality. However, in any catch-and-release fishery, a proportion of fish will become inadvertently deeply hooked (e.g., in the gullet) and numerous studies have shown this to

Population dynamics models used to provide management advice for harvested natural resources often estimate population processes that can be mutually confounded. These processes (e.g., natural mortality (M) and catchability (q)) are often assumed to be time-invariant, but this assumption can be violated in real populations. Not allowing for time-variation in these processes can result in retrospective

Patterns of genetic connectivity can be used to define the geographic boundaries of fishes and underpin management decisions. This study used a genetic multi-marker approach to investigate the population structure of scalloped hammerheads (Sphyrna lewini) in the Indo–Pacific. Samples from 541 S. lewini were collected from 12 locations across the Indo–Pacific. Samples were analysed using two regions

The effect of stock enhancement on increasing biomass is not well understood and is highly controversial because released fish might have a competitive impact on wild stocks. Quantitative assessments exploring the possible impacts of stock enhancement on population dynamics are rare, especially in data-limited fisheries. We developed a state-space production model incorporating stock enhancement to

The inclusion of fishery-independent data in stock assessments has been shown to have positive stock and financial outcomes for fisheries. A co-management approach between the government and commercial fishers in this limited-entry fishery led to the successful implementation of industry-funded, fishery-independent surveys of crystal crab, a deep water Geryonid crab, in two areas off Western Australia

The ability of populations to persist and adapt to environmental changes is based on genetic diversity. Substantial empirical data shows that the genetic integrity of natural fish population is being compromised by the effect of anthropogenic interventions and robust environmental conditions. Genetic diversity estimates were obtained for 210 individuals of Cyprinus carpio sampled from six sites of

There is increasing consensus of the need for ecosystem-based fisheries management (EBFM), which accounts for trophic interactions and environmental conditions when managing exploited marine resources. Continued development and testing of analytical tools that are expected to address EBFM needs are essential for guiding the management of fisheries resources in achieving and balancing multiple social

We evaluated natural mortality (M yr−1) estimation reliability for eastern Aleutian Islands male golden king crab (Lithodes aequispinus), an exploited stock, by comparing an integrated length-based assessment model approach and a likelihood method using tag release-recapture data. We used 1997, 2003, and 2006 tag release-recapture data to estimate the size transition matrix, M, fishing mortality, total

Incorporating multiple samples for estimation is becoming increasingly popular across industries and disciplines. Indeed, various fisheries agencies combine samples when estimating catch totals. In this paper, we examine a probabilistic matching technique to link a non-probability sample of electronic reports of fishing trips with a dockside probability sample. We use 2017 data from a capture-recapture

As part of attempts to improve selection among south-eastern Australian benthic fish trawls, an experiment was done to assess: (1) for confounding effects of a narrower-than-recommended hooped cover over a conventional trawl codend; and then (2) the associated size selection of eastern school whiting, Sillago flindersi; and (3) if this could be improved by inserting a large panel of smaller square-shaped

Understanding satisfaction is an important aspect of the management of recreational fisheries. We investigated fishing trip satisfaction from data collected via a Danish citizen science platform that allows anglers to report information from their fishing trips through a smartphone application and a webpage. Trip satisfaction was related to a set of predictor variables covering classical catch constructs

Shallow-water hake (Merluccius capensis) is a valuable demersal resource distributed throughout the Benguela Current region, from southern Angola to eastern South Africa. Previous molecular work revealed distinct populations confined to the northern and southern Benguela sub-systems, with asymmetrical migratory patterns. Here, we re-evaluated the geographic position of the genetic break in shallow-water

Natural mortality (M) is crucially important for stock assessment since it strongly influences estimates of spawning stock biomass, MSY and fishing mortality. Variation in M can occur between sexes, maturity stages and temporally. Estimates of M are confounded with those of catchability, recruitment, and growth. Previous studies, which focused on age-structured population dynamics models, suggest that

Fishing trials were carried out with a demersal trawl fitted with an inclined grid in the extension. Fibre optic cables were attached to the grid allowing the illumination of the top and bottom halves of the grid independently. Fish that passed through the top half of the grid entered one codend whereas those that passed through the lower half of the grid entered another. Four lighting configurations

Large-scale surveys have been used to estimate the value of recreational fishing over large areas and time periods in the past, but there is a lack of information regarding the value of smaller event based recreational fishing activities. Using the travel-cost method, we estimate the overall value generated by two regional spearfishing competitions in eastern Australia and the adjusted value per competitor

Marine gastropods are key items in small-scale fisheries worldwide, generating employment and high economic value in international markets. In North Patagonian Gulfs (Southwestern Atlantic), gastropods are landed as by-catch in bivalve artisanal fisheries, and thus no official statistics are reported. Recently, the first regulation of marine gastropod catches was established based on size at maturity

Temporal variation in natural mortality (M) has been recognized for having a degrading effect on the performance of stock assessment models when it is not accounted for in the model. However, time-invariant M has remained widely practiced in stock assessments due to the difficulties in estimation. Therefore, in this study we conducted simulation-estimation experiments to (1) evaluate the ability of

The vermilion rockfish complex consists of two distinct species, vermilion rockfish (Sebastes miniatus) and sunset rockfish (S. crocotulus) with clear haplotypic differences. Due to a one-way mitochondrial introgression from vermilion into sunset rockfish a high proportion (20–30%) of fish with a vermilion haplotype are characterized as sunset based on nuclear genotype (introgressed sunset, hereafter

Incidental capture in gillnets is the most pressing threat for small cetaceans worldwide. One reason why small, echolocating cetaceans entangle in gillnets may be their inability to acoustically detect gillnets and classify them as obstacles. To increase the overall acoustic reflectivity as well as alter the perceived image to simulate an impenetrable barrier, small reflective objects – 8 mm wide acrylic

The aim of this study was to compare the catch quality of Northeast Atlantic cod (Gadus morhua) in the Barents Sea bottom trawl fishery caught using the conventional configuration (a sorting grid followed by a diamond mesh (T0) codend) and a T90° turned mesh codend (T90) without a grid. Twenty hauls were conducted, consisting of 10 hauls with the conventional configuration and 10 hauls with the T90-codend

Female reproductive dynamics of the offshore American lobster fishery are not well understood due to the difficulties associated with biological sampling offshore. This lack of knowledge limits our understanding of population dynamics and the impacts of fishery removals on the offshore lobster resource. Addressing needs identified by stock assessment scientists, we determined the size at which female

Overexploitation and consequent depletion of the breeding stock is one of multiple stressors affecting Mediterranean trout Salmo cettii Rafinesque, 1810 in central Italy. The practice of total Catch and Release (C&R), combined with gear restrictions and seasonal closures, reduces catch-related impacts. To test for the effects of C&R management, the goals of the study were to: (i) analyse the status