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Hagfish

Hagfish are primitive, eel-shaped marine vertebrates belonging to the class Myxini within the superclass Agnatha, distinguished by their lack of jaws, true vertebrae, paired fins, and scales, as well as their cartilaginous endoskeleton supported primarily by a persistent notochord.^[1]^[2] They possess rudimentary eyes reduced to light-sensitive spots, a single nostril, and a circular mouth armed with two rows of horny teeth for rasping flesh from carcasses.^[3] Hagfish are renowned for their defensive ability to secrete vast quantities of slime from specialized glands, which expands rapidly in water to form a gelatinous barrier against predators.^[4] There are approximately 76 recognized species, divided among several genera in the family Myxinidae, making them a relatively diverse yet ancient lineage that has persisted for over 500 million years.^[5]^[4] These bottom-dwelling scavengers inhabit cold, deep marine environments worldwide, from coastal shallows to abyssal depths exceeding 1,700 meters, where they burrow into sediments or hide in crevices during the day and emerge at night to feed.^[6] Hagfish play a vital ecological role as decomposers, consuming dead or dying fish and invertebrates, thereby recycling nutrients on the ocean floor and preventing the accumulation of organic waste that could otherwise lead to hypoxic conditions.^[5] Their diet consists primarily of carrion, supplemented occasionally by live prey such as polychaete worms or small crustaceans, which they access by entering the body cavities of larger animals through orifices.^[6] Reproduction is poorly understood but believed to be oviparous, with females laying gelatinous eggs in clusters; hagfish exhibit low metabolic rates and slow growth, contributing to their vulnerability in exploited fisheries.^[5] Anatomically, hagfish represent a basal vertebrate group, with a decentralized nervous system, no true stomach, and a low-pressure circulatory system lacking many specialized organs found in more derived fishes.^[7] Their flexible, mucus-covered bodies enable unique behaviors, such as tying into overhand knots to gain leverage for tearing food, escape predators, or remove excess slime after a defensive discharge.^[8] Evolutionarily, hagfish diverged early from the vertebrate lineage, sharing some traits with lampreys (the other jawless fish group) but differing in key features like the absence of vertebral elements, positioning them as a critical model for understanding the origins of the cranium and basic vertebrate body plan.^[7] Despite their "living fossil" status, recent genomic studies highlight their distinct evolutionary trajectory, with a genome that informs debates on cyclostome monophyly and gnathostome origins.^[9]

Taxonomy and evolution

Classification

Hagfish are classified within the class Myxini, also known as Hyperotreti in some older systems, under the order Myxiniformes and the single family Myxinidae.^[10] This family encompasses approximately 80 recognized species distributed across six genera, though traditional classifications often emphasize two primary genera: Myxine, associated with northern hemisphere waters, and Eptatretus, prevalent in southern regions.^[10]^[11] Key species include Myxine glutinosa, the Atlantic hagfish, found along the coasts of Europe and North America in the North Atlantic Ocean; Eptatretus stoutii, the Pacific hagfish, inhabiting the eastern Pacific from Alaska to Chile; and Eptatretus deani, the black hagfish, distributed in the northeastern Pacific.^[12] Other notable examples are Myxine circifrons from the southwestern Atlantic and Eptatretus minor from the Indo-Pacific, highlighting the family's global marine distribution. Historically, hagfish taxonomy has involved debates over their grouping with lampreys, traditionally united in the superclass Cyclostomata based on shared jawless morphology.^[13] However, molecular phylogenetic analyses have resolved hagfish and lampreys as distinct classes—Myxini and Petromyzontida, respectively—supporting a monophyletic Cyclostomata (cyclostomes), in which hagfish and lampreys are sister taxa that together form the sister group to gnathostomes (jawed vertebrates).^[14] Species delineation in hagfish relies on morphological traits such as the number of gill pouches, which varies from one to sixteen across taxa, and the arrangement of cusps on the fused dental plate forming tooth-like structures.^[11] Genetic criteria, including mitochondrial 16S rRNA and cytochrome c oxidase subunit I (COI) sequences, have increasingly complemented these features to distinguish cryptic species and resolve phylogenetic relationships within genera like Eptatretus.^[15]^[11]

Phylogenetic position

Hagfish represent basal craniates; hagfish and lampreys together form the monophyletic clade Cyclostomi, which is the sister group to gnathostomes (jawed vertebrates). Within Cyclostomi, hagfish (Myxini) are the sister group to lampreys (Petromyzontida).^[16] This phylogenetic placement is robustly supported by molecular data, such as analyses of ribosomal RNA and whole-genome sequences, which indicate that cyclostomes diverged from gnathostomes approximately 500 million years ago during the Cambrian period.^[17]^[16] Within Cyclostomi, hagfish and lampreys further diverged around 450 million years ago in the Ordovician.^[9] Key synapomorphies shared by hagfish and other vertebrates include the presence of a cranium enclosing the brain and sensory organs, as well as a dorsal nerve cord.^[16] However, hagfish lack true vertebrae, instead retaining a persistent notochord throughout life, which underscores their basal position among craniates.^[9] The monophyly of Cyclostomi has been a subject of debate, with early morphological studies suggesting paraphyly—placing hagfish as more primitive and outside the vertebrate clade, while lampreys aligned closer to gnathostomes based on features like branchial baskets.^[18] In contrast, molecular evidence from the 1990s onward, bolstered by recent phylogenomic analyses incorporating microRNAs and extensive gene datasets, has consistently confirmed cyclostome monophyly, with hagfish and lampreys as sister taxa to gnathostomes.^[19]^[18]^[16] The fossil record provides insights into hagfish origins, with the earliest hagfish-like forms appearing in the Cambrian, such as Myllokunmingia fengjiaoa from ~520 million years ago in the Chengjiang biota, interpreted as a stem craniate with vertebral elements. The oldest known hagfish fossil is Myxinikela siroka from the Late Carboniferous Mazon Creek Lagerstätte (~300 million years ago). Unambiguous hagfish fossils remain scarce; a notable specimen preserving soft tissues like slime glands is Tethymyxine macrospinosus from the early Late Cretaceous (~100 million years ago) in Lebanon.^[20]

Anatomy and physiology

Body plan

Hagfish exhibit a primitive, eel-like body form characterized by an elongated, cylindrical shape that typically measures 50–80 cm in length, though some species, such as the goliath hagfish (Eptatretus goliath), can reach up to 127 cm.^[21] Their skin is scaleless, smooth, and embedded with numerous epidermal mucus glands that contribute to their slippery texture.^[22] Unlike most vertebrates, hagfish lack jaws, paired fins, and a true stomach; instead, their digestive tract features a straight intestine for processing ingested material.^[23] The absence of a bony skeleton is notable, with support provided entirely by cartilaginous elements.^[22] The head region is distinctive, featuring a single median nostril that serves as the primary olfactory opening and leads to the pharynx.^[3] Lateral to the head are 5–16 pairs of gill pouches, each opening externally through a separate aperture for respiration.^[24] Feeding is facilitated by a protrusible, rasping tongue armed with two rows of pointed, keratinous teeth attached to dental plates, which allow the hagfish to bore into prey or carrion.^[3] Body coloration varies among species and individuals, ranging from pinkish or tan to dark brown or gray, often blending with muddy sediments in their benthic habitats for camouflage.^[25] The tail terminates in a low, continuous finfold that encircles the caudal region, extending dorsally and ventrally without distinct separation into median fins; this structure aids in propulsion during undulatory swimming.^[26] Sexual dimorphism is evident, with females generally larger than males and possessing paired oviducts for egg transport, while males are smaller and feature a prominent cloacal papilla through which sperm is released during external fertilization.^[27]^[28]

Slime production

Hagfish are equipped with over 100 slime glands distributed along the flanks of their body, typically numbering between 90 and 200 per individual depending on the species. These glands are specialized structures that house two primary cell types: gland mucous cells, which synthesize and store mucin vesicles, and gland thread cells (also known as club cells due to their shape), which produce compact, coiled bundles called thread skeins. Upon ejection from the glands, typically in response to predator attack or mechanical stress, the contents mix with seawater, initiating rapid transformation into slime.^[29]^[30]^[31] The resulting slime is a hydrogel primarily composed of water (over 99%), with the solid fraction consisting of approximately 30% protein threads derived from the unfolded skeins and the remainder mucin glycoproteins from the vesicles. Each thread skein, a compact coiled bundle ~100 µm in size, unravels into protein filaments up to 15–30 cm long and 12–15 nm in diameter, enabling the production of extensive fibrous networks. This interaction causes the slime to expand up to 10,000-fold in volume within seconds, forming a low-viscosity gel that is pH-neutral (functional across pH 6–9) and exhibits minimal oxygen consumption, allowing persistence in oxygen-poor deep-sea conditions.^[32]^[33]^[34] Slime production represents an evolutionary adaptation for defense, enabling hagfish to deter predators by rapidly deploying a substance that can clog gills upon brief contact. While slime glands are evident in the fossil record of hagfish dating back to the Cretaceous period (approximately 100 million years ago), actual slime preservation is exceedingly rare due to its ephemeral, soft-tissue nature. Recent research as of 2025 highlights the self-assembling properties of hagfish threads, inspiring applications in deployable biomaterials such as strong, lightweight fibers for textiles and medical scaffolds.^[35]

Respiratory system

Hagfish respiration primarily occurs through 5 to 16 pairs of internal gill pouches, the number varying by species, each containing horizontal lamellae that facilitate gas exchange across a thin epithelium.^[36] Unlike most fish, hagfish lack an operculum, with the gills housed internally beneath folds of skin that open externally via gill slits.^[37] This arrangement supports efficient oxygen extraction in low-oxygen environments. Water flow through the respiratory system is unidirectional, entering via the single nostril or mouth and propelled by rhythmic contractions of the velar muscles into the pharynx, before being directed over the gills and exhaled through the gill slits. This continuous pumping mechanism, operating at rates around 125 ml kg⁻¹ min⁻¹ in resting Pacific hagfish at 12°C, aligns with their low metabolic rate of approximately 1.5 µmol O₂ g⁻¹ h⁻¹, conferring remarkable tolerance to hypoxia and even prolonged anoxia.^[38]^[39]^[40] Accessory oxygen uptake supplements branchial respiration via minor cutaneous diffusion across the skin and the branchial basket, though gills account for over 80% of total uptake even under stress.^[41] Hagfish hemoglobin, characterized by high oxygen affinity (P₅₀ around 1–5 mmHg at physiological conditions), is particularly suited to loading oxygen in the cold, hypoxic depths they inhabit.^[42] Branchial chloride cells, located in the gill epithelium, play a key role in ion regulation by facilitating chloride uptake and acid-base balance, which helps maintain internal osmolarity and avert dehydration despite the hagfish's osmoconforming physiology in marine saltwater.^[43]

Circulatory system

Hagfish possess a unique circulatory system characterized by multiple accessory hearts that facilitate low-pressure blood flow. The primary pumps include the branchial heart, which propels deoxygenated blood through the gills for oxygenation, and the portal heart, which drives blood through the hepatic sinusoids before it returns to the branchial circulation. Paired caudal hearts assist in returning venous blood from the posterior body and tail to the central system. These hearts lack a true ventricle and instead rely on simple, rhythmic pulsatile contractions generated by trabeculated myocardial tissue to maintain circulation.^[44]^[23]^[45] The hagfish circulatory system is closed but features extensive venous sinuses that contribute to a partially open-like architecture, allowing blood to pool and mix minimally with interstitial fluids in low-pressure compartments. Mean blood pressure in the dorsal aorta typically ranges from 3 to 8 mmHg, with pulse pressures around 25 mm H₂O, reflecting the system's high compliance and adaptation to a sedentary, deep-sea lifestyle. Blood volume is notably high at approximately 180 mL/kg, and red blood cells contain monomeric hemoglobin with exceptionally high oxygen affinity and a modest Bohr effect, enabling efficient oxygen uptake in hypoxic environments without a Root effect for enhanced unloading.^[46]^[47]^[44]^[48]^[49] Osmoregulation in hagfish relies on near-conformity to seawater osmolarity, achieved primarily through intracellular accumulation of free amino acids rather than urea retention, maintaining plasma osmolarity close to 1000 mOsm/L. The kidneys feature glomeruli with low filtration rates, producing iso-osmotic urine that minimally regulates electrolytes, allowing tolerance to moderate salinity fluctuations via adjustments in amino acid levels. Unlike elasmobranchs, hagfish lack a rectal gland for salt secretion. Unique aspects include the absence of a spleen, with hematopoietic tissue diffusely distributed in the intestine and body wall, and no renal portal system, while the hepatic portal system efficiently processes nutrients from the gut before returning blood centrally.^[50]^[51]^[52]^[47]^[53]

Nervous system and senses

The nervous system of hagfish is characterized by a relatively small brain that constitutes approximately 0.1% of body mass, reflecting their basal position among vertebrates.^[54] This brain lacks a distinct cerebellum and the corpus callosum seen in higher vertebrates, with its organization divided into telencephalic, diencephalic, mesencephalic, and rhombencephalic regions.^[54] The olfactory bulbs are prominently developed and dominant, underscoring the primacy of chemosensation in processing environmental cues.^[55] Hagfish possess 10 pairs of cranial nerves, which facilitate sensory input and motor control in a decentralized manner, allowing for peripheral processing that supplements the modest central integration provided by the brain.^[56] Sensory capabilities emphasize non-visual modalities adapted to their deep-sea habitat. The single median nostril serves as the primary olfactory organ, drawing in water to detect carrion and other chemical signals from considerable distances, enabling efficient scavenging.^[57] Unlike many fish, hagfish lack a lateral line system but compensate with highly touch-sensitive skin embedded with mechanoreceptors and free nerve endings for tactile exploration.^[58] Specialized electroreceptors are present in the head region, aiding in the detection of weak bioelectric fields from prey or conspecifics.^[55] Vision is rudimentary and incapable of image formation due to degenerate eyes that lack a lens, iris, and organized retinal layers, rendering them ineffective in the dark abyssal environment.^[59] Consequently, hagfish exhibit strong behavioral reliance on olfaction and touch for navigation, foraging, and predator avoidance in low-light conditions, with olfactory cues guiding them to food sources over visual alternatives.^[60]

Musculoskeletal system

The musculoskeletal system of hagfish relies on a persistent notochord as the primary axial skeleton, a flexible rod of vacuolated cells encased in tough connective tissue sheaths that provides longitudinal stiffness and resists compression during movement. This structure extends the full length of the body, enabling pronounced bending and twisting without the need for vertebral support. Unlike jawed vertebrates, hagfish possess no vertebrae, ribs, or other bony elements, maintaining an entirely cartilaginous and fibrous skeletal framework throughout life. The axial musculature is dominated by the parietal muscle, a thick sheet-like layer of longitudinal and circular fibers that wraps around the notochord and extends from the head to the tail, reaching maximum thickness ventrally. These muscle bands facilitate undulatory locomotion through alternating contractions that propagate waves along the body, while the non-segmented arrangement of fibers—lacking distinct myomeres seen in other fishes—allows exceptional flexibility for tying the body into knots, providing leverage for tasks like burrowing or manipulation.^[61]^[62] Hagfish lack paired fins and fin rays, but feature a low, continuous dorsal finfold along the trunk and a rounded caudal fin that contribute to stability during slow, sinusoidal swimming. The dorsal finfold is supported by simple cartilaginous elements rather than elaborate rays, reflecting their preference for benthic burrowing over active swimming, where head rasping against substrates aids progression. This knot-tying capability, enabled by the musculoskeletal design, also supports feeding behaviors such as tearing flesh.^[63]^[64] Growth in hagfish is indeterminate and continuous, involving elongation of the notochord through cell addition and expansion, with no formation of bone or replacement of cartilaginous tissues, preserving the primitive skeletal configuration into adulthood.^[65]

Life history

Reproduction

Hagfish are primarily dioecious, though hermaphroditism occurs in some individuals, particularly juveniles in certain species. The reproductive biology of hagfish remains incompletely understood, primarily because mating has never been directly observed in the wild and is exceedingly rare even in captivity.^[66]^[67]^[68] Fertilization in hagfish is believed to be internal and is achieved without a dedicated copulatory organ. Males possess an elongated urogenital papilla, which may be used to transfer sperm to the female, potentially in packets embedded within slime produced by specialized cloacal glands that enlarge prior to breeding seasons; however, the precise mechanism remains unconfirmed due to lack of observations.^[69]^[70] Mature females produce a low number of large, yolky eggs per reproductive cycle, typically 20–30 per clutch, with individual eggs measuring 15–25 mm in length and featuring tough, leathery shells anchored by adhesive filaments or threads that allow deposition either singly or in cohesive clusters.^[71]^[68] In certain species, such as the Atlantic hagfish (Myxine glutinosa), reproduction exhibits seasonality, with gonadal development and hormone levels (including gonadotropin-releasing hormone and steroids like estradiol and progesterone) peaking in response to environmental cues such as temperature fluctuations, though other species show year-round spawning capability.^[72] No parental care is provided after eggs are laid, leaving them to develop independently.^[68]

Development and growth

Hagfish undergo direct development, bypassing any free-living larval stage characteristic of many other vertebrates, including their cyclostome relatives the lampreys. Embryos develop internally within robust, gelatinous eggs that are typically 1.5 to 2.5 cm long and anchored in clusters by thin threads. This embryonic phase lasts 7 to 11 months, depending on species and environmental conditions, after which juveniles hatch as fully formed mini-adults approximately 5 to 8 cm in total length, possessing all major anatomical features of adults such as a functional notochord, rudimentary sensory organs, and the capacity for burrowing and scavenging.^[73]^[74]^[75] Post-hatching growth in hagfish is indeterminate and notably slow, with annual increments of 1 to 2 cm, allowing individuals to reach sexual maturity at lengths of 30 to 50 cm after 7 to 13 years. Unlike many fishes, hagfish lack otoliths for age estimation; instead, longevity is inferred from annual growth rings observed in the notochord or developing vertebral elements, suggesting lifespans of up to 25 to 50 years in some species. Metamorphosis is absent, and early juveniles exhibit behaviors similar to adults, including burrowing into sediments and scavenging detritus shortly after hatching.^[76]^[77]^[78]^[79] Recent research up to 2025 has highlighted genetic aspects of development, including the identification of germline-specific repetitive DNA sequences potentially linked to sex differentiation through chromatin diminution processes, though specific sex-determining markers remain elusive. Hagfish exhibit low fecundity, producing only 20 to 30 eggs per reproductive cycle, which, combined with their protracted development and slow growth, contributes to limited population recovery rates following disturbances.^[80]^[81]^[78]

Ecology and behavior

Habitat and distribution

Hagfish are distributed globally in temperate to subtropical marine waters across both the Northern and Southern Hemispheres, with a notable absence from polar regions. Their range encompasses all major ocean basins except the Arctic and Antarctic, reflecting an antitropical biogeographic pattern driven by historical vicariance events associated with seafloor spreading. This disjunct distribution results in two primary clades, one predominant in the northern hemisphere and the other in the southern, with significant endemism in isolated basins such as the Galápagos Islands, where multiple independent colonizations have led to unique species assemblages.^[82]^[83]^[84] These ancient craniates primarily inhabit benthic environments on continental slopes, fjords, and seamounts, where soft, muddy or silty sediments predominate to support their burrowing lifestyle. For instance, the Atlantic hagfish (Myxine glutinosa) occurs along the North Atlantic continental margins, including the Gulf of Maine and Laurentian Channel, while Pacific species such as Eptatretus polytrema are found off the coast of Chile in the southeastern Pacific, and various Eptatretus species inhabit waters near Japan in the northwest Pacific. Depths typically range from 50 to 2000 meters, though some populations extend to over 1100 meters in soft mud habitats.^[85]^[86]^[87]^[76]^[88]^[26]^[3] Hagfish thrive in abiotic conditions characterized by cold water temperatures of 4–15°C, perpetual low light, and elevated hydrostatic pressures typical of deep-sea settings. They exhibit exceptional tolerance to hypoxia and anoxia, enabling survival when burrowed in oxygen-poor mud; this adaptation supports their persistence in sediments with low oxygen levels, where they occasionally access buried food resources.^[89]^[76]^[90]

Feeding mechanisms

Hagfish are primarily scavengers, feeding on the carcasses of dead or dying fish, invertebrates, and larger marine mammals such as those found at whale falls.^[91]^[92]^[57] They occasionally prey on live polychaetes, nemerteans, shrimps, crabs, or small fish, but such opportunistic predation is rare compared to their scavenging habits.^[93]^[94]^[29] These fish detect potential food sources from long distances using their highly sensitive olfactory system, which responds to chemical cues from decaying organic matter.^[95] The feeding apparatus of hagfish is adapted for rasping and tearing soft tissues from carcasses, lacking jaws typical of most vertebrates. The mouth is surrounded by two pairs of tentacle-like barbels, and inside, a pair of dental plates lined with sharp, horny cusps serves as the primary grasping tool.^[92] A muscular, tongue-like velar structure protrudes the dental plates forward to rasp flesh, then retracts to pull ingested material into the pharynx.^[96] For larger prey, hagfish anchor their flexible body by tying it into a knot, which generates the pulling force needed to tear off substantial chunks of tissue against resistance.^[92] They often burrow directly into the body of a carcass, feeding from within to access nutrient-rich internal organs.^[57] Digestion in hagfish occurs without a true stomach, as the esophagus transitions directly into a straight intestine divided into fore- and hindgut regions by a muscular band.^[97] Lacking an acidic stomach for initial breakdown, they rely on enzymatic action in the intestine and possibly external digestion via skin absorption of dissolved nutrients from the hypoxic environment inside carcasses.^[98] The intestine, without a spiral valve, facilitates nutrient absorption over its full length through a permeable gut membrane that encloses ingested food.^[64] Hagfish can ingest entire small prey items or large volumes of semi-digested matter, enduring prolonged fasting periods between infrequent meals.^[98] In marine ecosystems, hagfish serve as key detritivores, rapidly processing carrion to recycle organic matter and nutrients in deep-sea and soft-bottom habitats.^[5] Their scavenging behavior helps maintain benthic health by preventing accumulation of organic debris, and their populations can achieve high biomass, making them significant in some commercial fisheries despite limited direct predation roles.^[99]^[100]

Defensive strategies

Hagfish employ a suite of specialized defensive strategies to evade predation in their deep-sea environments, where encounters with threats are infrequent but potentially lethal. These adaptations, evolved in response to their scavenging lifestyle, include rapid slime ejection, body knotting for escape, and behavioral evasion tactics such as burrowing. Such mechanisms allow hagfish to deter or outmaneuver predators despite their lack of scales, spines, or other typical fish defenses. The primary defense of hagfish is the ejection of a defensive slime that rapidly expands upon contact with seawater, forming a viscous gel that clogs the gills and sensory organs of gill-breathing predators, impairing respiration and vision to facilitate escape. This slime production is triggered by stress, such as during an attack, and a single hagfish can generate enough material to fill a five-gallon bucket within seconds, overwhelming the predator's ability to pursue. Observations of interactions with predators like the seal shark (Dalatias licha) demonstrate that the slime causes the attacker to gag, choke, and release the hagfish, often leading to the predator's retreat. The biochemistry of the slime, involving mucin vesicles and coiled protein threads that unravel and entangle structures like gills, enhances its clogging efficacy without requiring large initial volumes.^[101] In addition to slime, hagfish use their highly flexible, muscular bodies to form overhand knots, which serve as a mechanical defense by providing leverage to wrench free from a predator's grip or to amplify pulling force against restraints. This knot-tying behavior allows the hagfish to anchor one end of its body while using the other to escape holds, such as those from biting jaws, and is particularly effective in tight or slippery conditions post-slime release. Studies across species like Eptatretus stoutii and Myxine glutinosa show that these knots are formed through coordinated bends, twists, and tail insertions, enabling rapid escape from confined spaces or predatory grasps. Hagfish further reduce predation risk through evasive behaviors, including burrowing into soft sediments to create protective U-shaped tunnels that conceal them from view, often leaving only a mucus trail as camouflage in the murky deep sea. Their preference for dark, low-visibility habitats at depths of 100–1,000 meters minimizes chance encounters, while their scavenging on sunken carcasses keeps them partially hidden. Known predators are few, primarily consisting of sharks such as the seal shark and occasional marine mammals like harbor seals (Phoca vitulina), exerting selective pressure that favors these low-profile, reactive defenses over aggressive countermeasures.^[102]

Human interactions

Commercial uses

Hagfish are primarily harvested for human consumption, particularly in South Korea where they are regarded as a delicacy and prepared in dishes such as grilled salted hagfish (kkomjangeo) or fermented products like hagfish rice. The fishery supplies live or frozen specimens, with nearly all exports from North American Pacific coasts directed to Asian markets. In 2022, California landings alone reached approximately 694 metric tons, contributing to broader regional harvests that support this demand. Nutritionally, processed hagfish offer high protein content (around 10.8 g per serving) and moderate fat levels (5.4 g), making them a valued seafood option.^[103]^[104]^[105] The skins of hagfish are tanned into durable "eel skin" leather, prized for its strength relative to cowhide—and used in wallets, belts, and accessories. Pacific fisheries, especially off California, Oregon, and Washington, dominate this trade, with historical peaks in the late 1980s and 1990s driven by Korean demand. Although experimental fisheries in Washington ended in 1992 due to handling challenges, the industry persists through targeted trap fisheries elsewhere.^[106]^[107]^[103] Beyond food and leather, hagfish slime has attracted research interest for its potential in developing super-fibers, with protein threads exhibiting high extensibility surpassing Kevlar, though with lower tensile strength. Studies have explored recombinant hagfish intermediate filament proteins to create ultra-stiff, biomimetic materials for textiles or protective gear, with ongoing advancements reported through 2025. Enzymes from the hagfish gut, including those involved in lipid digestion, are under investigation for biotechnological applications, though commercial exploitation remains limited.^[108]^[109]^[110] Historically, hagfish were caught incidentally in groundfish trawls along the Pacific coast since the early 20th century, prior to the development of targeted fisheries in the 1980s spurred by Asian markets. This incidental harvest provided early economic value but lacked the scale of modern operations.^[111]

Conservation status

Most hagfish species are assessed as Least Concern or Data Deficient on the IUCN Red List, although most species are assessed as Least Concern or Data Deficient, nine species (12%) are considered threatened, including one Critically Endangered, based on 2011 assessments using 2009 data, reflecting limited data on many deep-sea populations but elevated risk for some.^[112] For instance, the New Zealand hagfish (Eptatretus cirrhatus) is rated Least Concern, while the Pacific hagfish (Eptatretus stoutii) is Data Deficient due to sparse monitoring.^[113]^[114] The main threats stem from overfishing for bait and leather production, alongside bycatch in bottom trawls and habitat disruption from demersal fishing gear.^[5] In regions like the northeast Pacific and Atlantic Canada, intensified harvests have led to population declines, with survey data indicating reductions beginning around 2000 in some areas.^[115] Conservation management includes harvest quotas, such as Canada's total allowable catch of 1,550 tonnes annually for Atlantic hagfish (Myxine glutinosa) in the Maritimes Region to prevent overexploitation.^[116] Ongoing research employs biomass modeling to estimate sustainable yields and inform policy, emphasizing hagfish's slow growth and low fecundity.^[117] Emerging concerns involve ocean acidification, which could indirectly impact reproduction and defensive slime production, though hagfish exhibit physiological tolerance to elevated CO₂ levels compared to other fishes.^[118] Climate change may drive subtle range shifts, but deep-sea distributions limit immediate vulnerabilities.^[119]

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Evidence from 18S Ribosomal RNA Sequences that Lampreys and ...
18S ribosomal RNA sequences from two hagfishes, two lampreys, a tunicate, a lancelet, and a number of gnathostomes support the monophyly of the cyclostomes.
[20]
Hagfish from the Cretaceous Tethys Sea and a reconciliation of the ...
Jan 22, 2019 · We report an unequivocal fossil hagfish from the early Late Cretaceous of Lebanon. The soft tissue anatomy includes key attributes of living hagfish.Missing: criteria | Show results with:criteria
[21]
A New Species of Giant Seven-gilled Hagfish (Myxinidae: Eptatretus ...
Eptatretus eos is a five-gilled species possessing a tube-shaped elongated snout and a very high slime pore count of 128–130, including 27 in the caudal series ...
[22]
Myxinidae - an overview | ScienceDirect Topics
... Myxinidae (with 5 genera and about 60 species). These two classes of craniates share many features such as the absence of jaws, scales, or paired fins ...
[23]
Gross anatomy of the Pacific hagfish, Eptatretus burgeri, with special ...
Mar 23, 2023 · The alimentary canal consists of a large simple intestine extending in a straight line (Figure 6a). Unlike most jawed vertebrates, hagfish have ...
[24]
A new species of hagfish, Eptatretus wandoensis sp. nov. (Agnatha ...
Apr 13, 2020 · They are characterized by an eel-like body shape and 1–16 pairs of gill apertures and gill pouches; however, they have no jaws, eyes, or fins ( ...<|control11|><|separator|>
[25]
Eptatretus strickrotti n. sp. (Myxinidae): First Hagfish Captured From ...
It is further unique because of a combination of the following features: slime pore counts; paired dorsal nasal sinus papillae; 12 gill pouches and gill ...Missing: nostril teeth
[26]
Range expansion and redescription of the hagfish Eptatretus walkeri ...
Jun 1, 2020 · Ventral fin-fold very low or vestigial, beginning approximately at middle of body and extending to cloaca. Caudal fin-fold developed except ...
[27]
Morphometics and Gonadal Development of the Hagfish Eptatretus ...
Nov 8, 2013 · Based on the size of the eggs, the number of eggs per female, the proportion of the population that contains large eggs, and the number of ...
[28]
[PDF] 22 Cyclostomes (Lamprey and Hagfish)
to release eggs and sperm so they can be externally fertilized. All ... (e) Urogenital papilla of the mature male elongated from the cloaca. (f) ...
[29]
Hagfish predatory behaviour and slime defence mechanism - Nature
Oct 27, 2011 · Hagfishes have a large battery of slime glands and 90 to 200 associated slime pores running laterally along the full length of each side of ...
[30]
Hagfish slime gland thread cells. II. Isolation and characterization of ...
The slime glands of hagfish have two major cell types, gland thread cells (GTCs) and gland mucous cells (GMCs), both of which upon contact with water ...Missing: club | Show results with:club<|control11|><|separator|>
[31]
Spontaneous unraveling of hagfish slime thread skeins is mediated ...
Apr 15, 2014 · The slime is formed via the interaction between seawater and two components released by the slime glands: mucin vesicles from gland mucous cells ...Missing: club | Show results with:club
[32]
Composition, morphology and mechanics of hagfish slime
Dec 15, 2005 · Hagfish slime consists of mucins and protein threads that are released from slime glands and mix with seawater to produce an ephemeral material with intriguing ...Missing: species delineation
[33]
Composition, morphology and mechanics of hagfish slime - PubMed
Hagfish slime consists of mucins and protein threads that are released from slime glands and mix with seawater to produce an ephemeral material with intriguing ...Missing: unfold length volume expansion pH oxygen
[34]
Hagfish slime exudate stabilization and its effect on slime formation ...
Jul 15, 2017 · However, when fresh exudate was mixed into seawater or phosphate buffer at pH 6-9, slime functionality was not affected, showing pH ...
[35]
Design Principles for Deployable Fibers Inspired by Hagfish Defense
Oct 7, 2025 · The slime consists of two primary components: mucus produced by gland mucous cells and fibrous threads produced by gland thread cells (GTC) ( ...
[36]
Ventilation and Gas Exchange - SpringerLink
The respiratory system of hagfishes consists of 6—14 pairs of lens-shaped or bilobed gill pouches each receiving a ventilatory water flow ...
[37]
Ventilation in Pacific hagfish (Eptatretus stoutii) during exposure to ...
Their respiratory system is composed of 6–14 pairs of lens shaped gill pouches (Bartels, 1998) receiving water flow from a short afferent gill duct connected ...
[38]
[PDF] The ventilation mechanism of the Pacific hagfish Eptatretus stoutii
We made anatomical and physiological observations of the breathing mechanisms in Pacific hag- fish Eptatretus stoutii, with measurements of nostril flow and ...
[39]
Confirmation of the low metabolic rate of hagfish - ScienceDirect.com
Confirmation of the low metabolic rate of hagfish. Author links open ... cirrhatus does not willingly withstand severe hypoxic conditions. Previous ...
[40]
Characterizing the Metabolic Capacity of the Anoxic Hagfish Heart
Pacific hagfish, Eptatretus stoutii, can recover from 36 h of anoxia at 10°C. Such anoxia tolerance demands the mobilization of anaerobic fuels and the ...
[41]
It's all in the gills: evaluation of O2 uptake in Pacific hagfish refutes a ...
Hagfish skin has been reported as an important site for ammonia excretion and as the major site of systemic oxygen acquisition.
[42]
Water regulates oxygen binding in hagfish (Myxine glutinosa ...
Apr 15, 2003 · Oxygen affinity decreases when water activity increases, indicating that water molecules stabilize the low-affinity,oligomeric state of the ...
[43]
Why do hagfish have gill "chloride cells" when they need not ...
The presence of carbonic anhydrase in gill ionocytes of hagfish supports the proposal that these cells function in acid–base regulation.Missing: dehydration saltwater
[44]
CIRCULATION IN THE HAGFISH, MYXINE GLUTINOSA L
It is concluded that the circulation in Myxine differs from circulation in vertebrates generally by a partial shifting of the blood-moving power from the ...
[45]
Cardiac function and circulation in hagfishes
The hagfish circulation contains a high volume of blood (180 mL∙kg−1) and is remarkable for the number of accessory pumps. Cardiac output from the branchial ...
[46]
Evolutionary origins of the blood vascular system and endothelium
Hagfish possess a second cardiomyocyte-containing chambered heart, the portal heart, which beats asynchronously with the systemic heart, as it propels blood ...
[47]
Hagfish - an overview | ScienceDirect Topics
The hagfishes have a vertebrate pattern of organization but have some physiological and morphological characteristics that are distinctly 'invertebrate' in ...Missing: plan | Show results with:plan
[48]
The hemoglobin system of the hagfish Myxine glutinosa - PubMed
May 18, 1995 · Hemoglobin (Hb) from the hagfish Myxine glutinosa is composed of six major monomeric subunits. Some of these subunits aggregate to dimers at ...
[49]
Adenosine Receptor Blockade and Hypoxia-Tolerance in Rainbow ...
These results suggest that adenosine modulates the circulating level of catecholamines in both hypoxic rainbow trout and hypoxic Pacific hagfish. Keywords:.
[50]
Renal Electrolyte and Fluid Excretion in the Atlantic Hagfish Myxine ...
Apr 1, 1981 · Myxinoids keep their extracellular fluids almost in osmotic equilibrium with the environment (Robertson, 1963), not by retention of urea or ...
[51]
Molecular basis of the unique osmoregulatory strategy in the inshore ...
We also revealed that the hagfish does possess the orthologs of the known osmoregulatory genes and that the transepithelial movement of inorganic ions in the ...
[52]
Molecular basis of the unique osmoregulatory strategy in the inshore ...
Aug 1, 2024 · Our data indicate that the hagfish possesses an ability to conduct free amino acid (FAA)-based osmoregulation at a cellular level.Missing: urea | Show results with:urea
[53]
The sui generis gut of the hagfish: a focal point of hagfish physiology
Jul 16, 2025 · The cardiovascular system of hagfish is very unusual. ... Hagfishes do not have a true spleen, and instead the tissue responsible for blood ...Missing: gonads | Show results with:gonads
[54]
The Central Nervous System of Jawless Vertebrates
Feb 18, 2017 · Firstly, a foraging hagfish uses its sensory barbels and olfactory organs to locate the burrows of their prey, and then it utilizes its dental ...
[55]
Nervous and Sensory Systems - ScienceDirect.com
The hagfish brain comprises telencephalic, diencephalic, mesencephalic, and rhombencephalic divisions, although the presence of a. Functional Classification ...
[56]
Central Nervous System – Comparative Vertebrate and Human ...
However, beyond that, there is little to distinguish the hagfish brain from other vertebrates. ... The corpus callosum is the largest commissure, allowing ...<|separator|>
[57]
Behavioural responses of the hagfish Eptatretus stoutii to nutrient ...
Sep 16, 2019 · Regardless of feeding mode, the detection and localisation of sea-floor carrion and/or prey items by hagfish must require well-adapted ...
[58]
Cutaneous Exteroreceptors and their Innervation in Hagfishes
Two sensory systems are examined in detail: the lateral line system and a chemoreceptive system which is unique to hagfishes.
[59]
Vertebrate features revealed in the rudimentary eye of the Pacific ...
Jan 13, 2021 · Hagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens and a retinal architecture ...
[60]
Consciousness in Jawless Fishes - PMC - PubMed Central
The most prominent sensory modality in the hagfish is olfaction. Its main brain center is the pallium, the forebrain region homologous to the mammalian cortex ...Missing: sources | Show results with:sources
[61]
(PDF) Material Properties of Hagfish Skin, with Insights into Knotting ...
Aug 5, 2025 · ... hagﬁsh species, the skins of all hagﬁsh are. Received 16 June ... parietal muscle is not divided into dorsal and. ventral portions like ...
[62]
[PDF] The Body Design of Hagfishes (Eptatretus stoutii and Myxine ...
Hagfish musculature The parietal muscle of the hagfish extends downward from the mid-dorsal line, reaching its greatest thickness at the ventral surface of the ...
[63]
Jawless Fishes: Superclass Agnatha - OpenEd CUNY
Hagfishes have a cartilaginous skull, as well as a fibrous and cartilaginous skeleton, but the major supportive structure is the notochord that runs the length ...
[64]
Hagfish: Structure, Affinities, System and Other Details
The alimentary canal is a straight tube with a comparatively wide intenstine. The 'tongue' is well-developed and is operated by elaborate tongue musculature.
[65]
Hagfish and lancelet fibrillar collagens reveal that type II ... - NIH
It has been suggested that the notochord may represent a primitive form of cartilage, based on their many shared structural, cellular, and molecular properties, ...
[66]
Morphometics and Gonadal Development of the Hagfish Eptatretus ...
Nov 8, 2013 · Cloacal depth is measured at the anterior portion of the cloaca, excluding the dorsal fin fold, whereas tail depth is the perpendicular depth ...
[67]
Hagfish Species Profile, Alaska Department of Fish and Game
Very little is known about hagfish mating. Reproduction and spawning have never been witnessed or documented, and they've never successfully reproduced or ...Hagfish (eptatretus Deani) · General Description · Life HistoryMissing: behavior seasonality
[68]
Sex Difference in the Cloacal Gland in the Hagfish, Eptatretus ...
Aug 7, 2025 · The cloacal gland consists of mucus and thread cells, as do the lateral slime glands. The sperm may be entangled within slime in the cloacal ...
[69]
Gonads and Reproduction in Hagfishes - SpringerLink
There is no copulatory organ in any species of hagfish and the mode of fertilization is still not clear. Investigation on the adenohypophysial region in M ...
[70]
Identification of a functional corpus luteum in the Atlantic hagfish ...
There is new evidence from our recent studies that Atlantic hagfish may have a seasonal reproductive cycle.
[71]
Reproductive biology and ecology of Pacific hagfish (Eptatretus ...
Apr 5, 2021 · Our results found that the reproductive characteristics of both hagfish species reflect those of K-selected species, which tend to live long and exhibit slow ...
[72]
https://academic.oup.com/icb/article/45/1/158/604629
[73]
Pacific Hagfish | Online Learning Center
Apr 1, 2013 · A mature female produces between 20-30 eggs per reproductive cycle that average 5mm (0.2 in) in length. There is no larval stage. Hatchlings are ...Missing: clutch | Show results with:clutch
[74]
(PDF) Developmental Biology of Hagfishes, with a Report on Newly ...
Aug 6, 2025 · In this review, we summarize recent developmental data from these hagfish embryos and discuss a plausible evolutionary scenario for vertebrate ...<|control11|><|separator|>
[75]
Hagfish Development - BioOne Complete
Hagfish development is a largely unexploited research area. The reason for this is simply the unavailability of hagfish embryos.Missing: bone | Show results with:bone
[76]
[PDF] A review of the biology of Atlantic hagfish (Myxine glutinosa), its ...
The biology of hagfishes has received considerable interest and attention in aspects related to their evolution, morphology, physiology and genetics, owing ...
[77]
[PDF] Inference on energetics of deep-sea fish that cannot be aged - Bio
The maximum clutch size was 38 eggs. We assumed that Atlantic hagfishes produce only one clutch per year at a temperature of 6 °C, fol- lowing the ...
[78]
Growth, Feeding, and Age of the Inshore Hagfish, Eptatretus burgeri
May 21, 2025 · The generated growth curve predicted that the gonads start to develop only 4 years after hatching at the earliest. Eptatretus burgeri can live ...
[79]
Pacific Hagfish Enhanced Status Report - CA Marine Species Portal
Life Span. Hagfish are slow growing. Their maximum age is unknown, but evidence suggests that hagfish can live to be 25 to 50 years old.
[80]
Bioinformatic and fine-scale chromosomal mapping reveal the ...
We have identified 16 eliminated repetitive DNA families from eight hagfish species, with 11 of these repeats being selectively amplified in the germline ...
[81]
Current Knowledge of Hagfish Reproduction
It has been documented that at least two species of hagfish spawn throughout the year, for Myxine gluti- nosa females and those nearing ripeness, have been ...
[82]
Hyperotreti - Tolweb.org
Hagfishes have an antitropical distribution, most species living in relatively cold waters of the northern and southern hemispheres. They have practically ...Hagfishes · Introduction · Characteristics
[83]
[PDF] Panbiogeographical analysis of distribution patterns in hagfishes ...
Overall, vicariance is a major feature of hagfish distribution, suggesting vicariant differentiation of widespread ancestors as a result of sea-floor spreading ...Missing: clades hemispheres
[84]
[PDF] Review of the hagfishes (Myxinidae) from the Galapagos Islands ...
Feb 1, 2021 · Hagfishes are an ancient group of benthic marine craniates that are found in deep or cold waters around the world.
[85]
Jawless Vertebrates Colonize Ocean Floor Across 3 Mass Extinctions
Jun 13, 2024 · Hagfishes are jawless vertebrates that are either the living sister to all vertebrates or form a clade with lampreys, the only other surviving ...
[86]
HAGFISH IN THE NEW ZEALAND FJORDS ARE SUPPORTED BY ...
Apr 1, 2007 · Large volumes of forest litter are deposited in the New Zealand fjords, and likely recycled into available energy by microbial activity. In this ...
[87]
Pacific Hagfish at Home in a Deep Sea Sponge | Nautilus Live
Oct 29, 2019 · Pacific Hagfish at Home in a Deep Sea Sponge ... habitat southeast of the seamount that could harbor additional communities of corals and sponges.<|control11|><|separator|>
[88]
Fourteen-gilled Hagfish (Eptatretus polytrema) - iNaturalist
It is found in muddy and rocky bottoms of the southeastern area of the Pacific Ocean near the coast of Chile between Coquimbo and Puerto Montt, at depths ...
[89]
The curious case of the chemical composition of hagfish tissues—50 ...
There are approximately 60 known species of hagfish that can be divided into 2 groups: the myxinids (e.g. the Atlantic hagfish, Myxine glutinosa) and the ...
[90]
Surviving anoxia: the maintenance of energy production and tissue ...
Jul 10, 2020 · It is thought that hagfish are exposed to hypoxia when buried in the mud, and to anoxia while feeding inside a whale fall (Bucking et al., 2011 ...
[91]
[PDF] Feeding in Jawless Fishes - Valdosta State University – The Bonfire
Hagfishes are strictly marine and generally known to be opportunistic scavengers that feed on dead or dying vertebrates and inverte- brates (Martini 1998; ...
[92]
Morphology and kinematics of feeding in hagfish: possible functional ...
Nov 15, 2007 · There are approximately 60 identified species, which are primarily recognized as demersal scavengers feeding on dead or dying marine ...
[93]
[PDF] Hagfish predatory behaviour and slime defence mechanism
Oct 27, 2011 · Hagfishes are commonly considered to feed exclusively by opportunistic scavenging, having been observed primarily feeding on carrion falls7,8 or ...<|control11|><|separator|>
[94]
[PDF] Food Preferences of Atlantic Hagfish, Myxine glutinosa, Assessed by ...
Aug 10, 2016 · Atlantic Hagfish prey on invertebrates such as polychaetes, nemerteans, shrimps, and crabs, and scavenge larger vertebrate prey including fishes ...
[95]
The use of Atlantic hagfish (Myxine glutinosa) as a bioindicator ...
It is an eel-like scavenger, completely blind, with a specialised olfactory sense able to detect chemical cues of fallen carrion or fish by-catch over long ...
[96]
motor patterns of the feeding musculature in Atlantic hagfish, Myxine ...
When feeding, bilaterally folding dental plates protrude from the mouth, then forcefully retract. This cyclic protraction and retraction occurs in the anterior ...
[97]
THE HAGFISH - jstor
hag's digestive system also has its striking features. From the throat to the anus a long, rather unspecialized intestine runs straight through the animal.
[98]
experimental studies of hagfish digestive and nutritional physiology
Jul 15, 2019 · This Commentary provides critical insight into the key aspects of hagfish feeding and digestive processes, and highlights the pitfalls of this group as ...
[99]
[PDF] Review of the fisheries and biology of the Pacific Hagfish (Eptatretus ...
Hagfish are commonly known as slime eels because of the copious amounts of slime they secrete from mucous pores along their sides when agitated. E. stoutii ...<|control11|><|separator|>
[100]
Conservation status of the world's hagfish species and the loss of ...
Aug 10, 2025 · ... They are eel-like fishes living in demersal , temperate marine waters in both hemispheres. There are about eighty species of hagfish ( Knapp ...
[101]
Hagfish are not Slime “Eels”, Alaska Department of Fish and Game
“That sets up a gradient in the hagfish's body, it is absorbing nutrients from the whale and absorbing oxygen from the seawater through its tail, and it just ...Missing: demand | Show results with:demand<|control11|><|separator|>
[102]
Eptatretus stoutii - Pacific hagfish - Animal Diversity Web
Breeding intervals are unknown, but there is some evidence that individuals breed once yearly. Breeding season: There is no evidence of a breeding season.
[103]
Commercial coastal hagfish fishery | Washington Department of Fish ...
Worldwide, there are over 60 known species; however, just two, the Pacific (Eptatretus stoutii) and black hagfish (E. deani) are commonly found in Washington's ...
[104]
Pacific hagfish Enhanced Status Report - Marine Species Portal
The California hagfish fishery began as a result of foreign fishery depletion. In 1983, Korean “eel skin” leather products gained popularity.Missing: industry | Show results with:industry
[105]
Effect of steaming and hot smoking treatment combination on the ...
Jul 9, 2020 · Additionally, the processed hagfish exhibited good nutritional value with high contents of protein (10.8 g), fat (5.4 g), carbohydrate (12.1 g) ...
[106]
[PDF] 3 Pacific Hagfish, Eptatretus stoutii - CA.gov
hagfish increased in Korea. By 1985, 400 vessels were landing up to 3000 short tons. (2722 metric tons) annually. From 1986 to 1987 there were approximately ...Missing: tonnage | Show results with:tonnage
[107]
Hagfish slime turned into ultra-stiff fibre | Research - Chemistry World
Sep 15, 2017 · Scientists have demonstrated that they can use mild conditions to convert artificial hagfish slime into one of the stiffest protein-based fibres ever reported.Missing: super | Show results with:super
[108]
Engineered Recombinant Hagfish Intermediate Filament Proteins
Hagfish slime consists of mucins and protein threads that are released from slime glands and mix with seawater to produce an ephemeral material with intriguing ...
[109]
Design Principles for Deployable Fibers Inspired by Hagfish Defense
Oct 7, 2025 · Hagfish produce extraordinary slime as a defense mechanism, releasing exudate from glands that rapidly form a fibrous, soft, ultra-dilute, water ...Missing: research super- patents
[110]
Activity and post-prandial regulation of digestive enzyme ... - NIH
Apr 5, 2019 · Recent evidence has suggested that hagfish have a regulated and specific mechanism by which lipids can be acquired in the hindgut [47] and ...
[111]
[PDF] Fisheries Report Department of Fish and Game Marine ... - CA.gov
Pacific hagfish are now the target of a robust, statewide re-emerging fishery. However, prior to 1982, hagfish were not landed or targeted by California.
[112]
IUCN Red List of Threatened Species
Three Arctic seal species moved closer to extinction in the latest update of the IUCN Red List. The 2025-2 update also reveals more than half of bird species ...About · 3.1 · Searching The IUCN Red List · Citing The IUCN Red List
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Eptatretus cirrhatus, Broadgilled hagfish : fisheries - FishBase
IUCN Red List Status (Ref. 130435: Version 2025-1). Least Concern (LC) ; Date assessed: 09 November 2009. CITES. Not Evaluated. CMS (Ref. 116361). Not Evaluated ...
[114]
Pacific hagfish - Wikipedia
... low dissolved oxygen levels. Additionally, hagfish may also experience low oxygen levels when burrowing into sediments on the sea floor. Movement. edit.
[115]
[PDF] Status of the Hagfish (Myxine glutinosa) Fishery in the Maritimes ...
Oct 31, 2018 · On the western side, they are found from Davis Strait and Greenland, off Labrador and Newfoundland, in the Gulf of. St. Lawrence and the Gulf of ...
[116]
2024 -2026 Atlantic hagfish (Maritimes Region)
Total allowable catches (TACs). The overall quota for the fishery is 1,550 tonnes. The quota is competitive. Management measures. The input controls and ...
[117]
[PDF] Resource and Market Analysis of Oregon's Hagfish Fishery - ODFW
Jan 4, 2019 · attacker to instantly release the hagfish when slime is secreted and make spasmodic attempts to ... 100 m, while large females prefer ...
[118]
Fish On Acid: Hagfish Cope With High Levels Of Carbon Dioxide
Increased acidity in the atmosphere is disrupting the ecological balance of the oceans, according to new research. The study ...Missing: acidification | Show results with:acidification
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Arctic seals threatened by climate change, birds decline globally
Oct 10, 2025 · The IUCN Red List now includes 172,620 species of which 48,646 are threatened with extinction. “Today's Red List update, launched at the IUCN ...<|control11|><|separator|>