Open research questions in Ichthyology and Marine Biology

What the literature leaves open

• Despite this, the Pacific eagle ray Aetobatus laticeps is a poorly studied species, which makes it difficult to assess its populations to implement or improve conservation and management measures.

  Habitat use of the Pacific eagle ray Aetobatus laticeps (Myliobatiformes: Aetobatidae) in a marine protected area of touristic importance, Banderas Bay, Mexico · 2026 · DOI

• The functional consequences of shark declines are often poorly understood due to the absence of empirical data describing long-term change.

  Long term declines in the functional diversity of sharks in the coastal oceans of eastern Australia · 2024 · DOI

• There is a lack of understanding of the drivers of non-compliance in Sri Lankan shark fisheries. Social dimensions are often overlooked in shark management and policy design.

  Assessing awareness and perceptions of shark fishing regulations for improved fisheries management · 2026 · DOI

• The deep sea is a challenging environment to study due to its remote and inhospitable nature. The identification of deep-sea species can be difficult due to the lack of knowledge on their morphology and genetics. The conservation and management of deep-sea species is a challenge due to the lack of data on their ecology and population dynamics.

  First record of an ilyophine eel (Anguilliformes, Synaphobranchidae) from the Southern Ocean · 2026 · DOI

• The Southern Ocean is a unique and understudied region for synaphobranchid eels. There is a lack of knowledge on the diversity and distribution of synaphobranchid eels in the Southern Ocean.

  First record of an ilyophine eel (Anguilliformes, Synaphobranchidae) from the Southern Ocean · 2026 · DOI

• Bait attraction in BRUVS may bias detection toward more inquisitive or food-motivated individuals, potentially inflating juvenile abundance estimates rather than reflecting true differences in abundance.

  Spatiotemporal patterns and habitat associations of blacktip reef shark in a shallow tropical bay · 2026 · DOI

• The small body size of neonates and young-of-the-year juveniles (< 90 cm) limited reliable identification from drone footage, representing a detection gap that prevented comprehensive juvenile assessment.

  Spatiotemporal patterns and habitat associations of blacktip reef shark in a shallow tropical bay · 2026 · DOI

• Overfishing of elasmobranchs. Lack of regulation and enforcement of conservation measures. Limited understanding of the ecological and economic impacts of elasmobranch fishing.

  Species Diversity, Conservation Status, and Policy Gaps of Landed Elasmobranchs at Ujungbatu Fish Landing Site, Jepara in Support of SDG 14 (Life Below Water) · 2026 · DOI

• The study is limited to a single fish landing site. The sample size is relatively small, with a total of 112 specimens. The study relies on visual inspection and morphological observation for species identification.

  Species Diversity, Conservation Status, and Policy Gaps of Landed Elasmobranchs at Ujungbatu Fish Landing Site, Jepara in Support of SDG 14 (Life Below Water) · 2026 · DOI

• The fragile skin, soft bodies, and poorly ossified skeletons of Careproctus snailfishes make it difficult to study their morphological characters. The use of genetic methods can be challenging due to the need for high-quality DNA samples.

  Whole-genome sequencing suggests taxonomic inflation in the Careproctus snailfishes (Liparidae) of the northeast Atlantic–Arctic region · 2026 · DOI

• The study does not provide a comprehensive analysis of all Careproctus species. The sample size may be limited, with only 11 specimens from the continental shelf and 2 from the continental slope.

  Whole-genome sequencing suggests taxonomic inflation in the Careproctus snailfishes (Liparidae) of the northeast Atlantic–Arctic region · 2026 · DOI

• The species' elusive nature makes it difficult to study. The lack of supporting data for the species' presence in Albanian waters makes it challenging to confirm its occurrence.

  First documented record of the smalleye squaretail, Tetragonurus cuvieri (Actinopterygii, Scombriformes, Tetragonuridae), in the Adriatic Sea · 2026 · DOI

• The paper identifies the challenge of requiring high-resolution, long-term, or ecologically comprehensive data. The paper notes the challenge of precision or optimization needing to temporarily yield to precaution in high-priority or data-poor contexts. The paper highlights the challenge of increasing anthropogenic and climate-driven disruption of nursery function.

  A decision tree to guide precautionary and adaptive tiering in marine nursery identification and management · 2026 · DOI

• The paper suggests that future research should focus on characterizing local drivers and connectivity processes. The paper emphasizes the need for continued investigation into the ecological drivers of juvenile recruit fitness and supply.

  A decision tree to guide precautionary and adaptive tiering in marine nursery identification and management · 2026 · DOI

• The paper identifies the challenge of limited knowledge of the biology and population dynamics of fishery resources. The paper notes the challenge of climate change and its impacts on fish populations. The paper highlights the challenge of human activities, such as overfishing and pollution, on fish populations.

  Challenges of Fishery Biology and Fish Population Dynamics in Fisheries Management · 2026 · DOI

• Increase biophysical studies that show the influence of environmental factors on resource dynamics - Studies on adaptation and resilience to the imminent climate change - Replication of the methodological approaches outlined in the Special Issue

  Challenges of Fishery Biology and Fish Population Dynamics in Fisheries Management · 2026 · DOI

• The study is based on a single sampling period. The sample size is limited to 17 individuals.

  SNP-based species identification of sympatric Carcharhinus galapagensis and C. obscurus sharks to support conservation monitoring in oceanic habitats · 2026 · DOI

• The study addresses the challenge of species identification in shark conservation. The study fills a knowledge gap in the understanding of shark biodiversity in the SPSPA.

  SNP-based species identification of sympatric Carcharhinus galapagensis and C. obscurus sharks to support conservation monitoring in oceanic habitats · 2026 · DOI

• The study faced challenges in tracking the sharks over long periods of time. The research was limited by the availability of data on the sharks' movement patterns. The study had to consider the complexities of the sharks' migration patterns and the factors that drive them.

  Seasonal residency and large-scale return migration patterns of basking sharks in high-latitude environments of the North Atlantic · 2026 · DOI

• The study only tracked 13 basking sharks. The tracking period was limited to up to 515 d. The study only investigated the movement patterns of basking sharks in high-latitude environments.

  Seasonal residency and large-scale return migration patterns of basking sharks in high-latitude environments of the North Atlantic · 2026 · DOI

• Regional multispecies patterns of elasmobranch occurrence remain poorly characterised. There is a need for comprehensive analyses of environmental and geomorphic drivers of elasmobranch occurrence.

  Temporal and spatial drivers of elasmobranch diversity and relative abundance in Lhaviyani Atoll, Central Maldives · 2026 · DOI

• The limitations of morphological stomach contents identification for shark diet analysis - The need for a more accurate and reliable method for prey identification

  DNA barcoding increases the taxonomic resolution of shark diet analysis compared to morphological stomach contents identification · 2026 · DOI

• These findings extend the known southeastern Mediterranean distribution of the Honeycomb Whipray, highlight the Gaza Strip as an under-reported hotspot for rare elasmobranch records, and emphasize the urgent need for fisheries monitoring, taxonomic verification, bycatch mitigation, and conservation measures for threatened batoids in Palestinian waters.

  Rare Records of the Exotic and Endangered Honeycomb Whipray (Himantura uarnak Forsskål, 1775) in the Mediterranean Waters off the Gaza Strip, Palestine · 2026 · DOI

• Further research on the biodiversity of the southern South China Sea is needed. The study of the ophidiid genus Sirembo can be continued to understand its taxonomy and phylogenetic relationships.

  A new cusk-eel, Sirembo quinquefasciatus (Ophidiiformes: Ophidiidae) from the southern South China Sea · 2026 · DOI

• The species is susceptible to population declines due to targeted and incidental fisheries. The study had to overcome the challenge of limited sampling in the Eastern Tropical Pacific. The analysis of genetic data required specialized software and expertise.

  Phylogeography and population genetics of the white spotted eagle ray, Aetobatus laticeps Gill, 1865, in the Eastern Tropical Pacific · 2026 · DOI

Most-cited papers in Ichthyology and Marine Biology

• Global catches, exploitation rates, and rebuilding options for sharks · Marine Policy · 2013 · 534 citations
• Global patterns in the bycatch of sharks and rays · Marine Policy · 2015 · 276 citations
• Shark interactions in pelagic longline fisheries · Marine Policy · 2007 · 210 citations
• A California Sea Lion (Zalophus Californianus) is Capable of Forming Equivalence Relations · The Psychological Record · 1993 · 195 citations
• Ecological roles and importance of sharks in the Anthropocene Ocean · Science · 2024 · 125 citations
• Diel movement patterns of the scalloped hammerhead shark (Sphyrna lewini) in relation to El Bajo Espiritu Santo: a refuging central-position social system · Behavioral Ecology and Sociobiology · 1984 · 122 citations
• Global shark fishing mortality still rising despite widespread regulatory change · Science · 2024 · 103 citations
• Official catch data underrepresent shark and ray taxa caught in Mediterranean and Black Sea fisheries · Marine Policy · 2019 · 83 citations
• Applying the phylogeographic concept to identify franciscana dolphin stocks: implications to meet management objectives · ˜The œjournal of cetacean research and management. Special issue · 2023 · 82 citations
• Rethinking use and trade of pelagic sharks from Brazil · Marine Policy · 2017 · 81 citations

Most recent work

• Only One Percent of Important Shark and Ray Areas in the Western Indian Ocean Are Fully Protected From Fishing Pressure · Ecology and Evolution · 2026
• Form, Function and Feeding: Changes in Tooth Size and Shape Associated With Ontogenetic Changes in Prey Consumption by Australian White Sharks ( Carcharodon carcharias ) · Ecology and Evolution · 2026
• Revealing the hidden patterns of shark and ray diversity over the past 145 million years · Current Biology · 2026
• Spatiotemporal patterns and habitat associations of blacktip reef shark in a shallow tropical bay · Environmental Biology of Fishes · 2026
• Integrative Taxonomy of Nuchequula longicornis (Teleostei: Leiognathidae) from Chinese Waters: Morphological Analysis, Mitogenomic Characterization, and Phylogenetic Implications · Biology · 2026
• Projected Habitat Contraction and Distributional Shifts of the near Threatened Undulate Ray Raja undulata Under Climate Change · Biology · 2026
• Manta munchies: plankton dynamics and feeding behaviour of reef manta rays (Mobula alfredi) around D’Arros Island in the Seychelles · Frontiers in Marine Science · 2026
• Assessing awareness and perceptions of shark fishing regulations for improved fisheries management · Oryx · 2026
• Partial sympatry of two interspersed Uroteuthis edulis (Loliginidae) clades reveals cryptic stock structure in the southern Taiwan Strait · Fisheries Research · 2026
• The Red Sea's largest coastal lagoon is a reproductive site for endangered whiprays and guitarfish · Endangered Species Research · 2026

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